CHANGES IN SPECTRAL AND PHOTOCHEMICAL PROPERTIES OF COLORED DISSOLVED ORGANIC MATTER IN A COASTAL ESTUARY

EPA Science Inventory

Colored dissolved organic matter (CDOM) is the primary determinant of UV penetration and exposure in freshwater and coastal environments. CDOM is photochemically reactive and its photoreactions can lead to reductions in UV absorbance and increased UV exposure in aquatic ecosystem...

Lessons learned on lead poisoning in children: one-hundred years on from Turner's declaration.

PubMed

Taylor, Mark P; Schniering, Carolyn A; Lanphear, Bruce P; Jones, Alison L

2011-12-01

There is significant emerging evidence showing life-long negative health, intellectual and socio-behavioural impacts as a result of childhood blood lead concentrations well below the widely used intervention level of 10 µg/dL. This issue raises serious health concerns for children in several Australian smelting and mining towns. Routine educational and home cleanliness advice to wet mop floors rather than to use a brush and pan to reduce lead exposure risks have been shown to have limited efficacy. This paper argues, as advocated 100 years ago by Queensland doctor Alfred Jefferis Turner, that childhood lead poisoning can only be mitigated via primary prevention and reduction of contaminants at source. Given that the effects of lead exposure are irreversible, there is a strong argument for the application of the precautionary principle to dealing with childhood lead exposure. There is a clear need to improve regulatory controls and emissions management to reduce environmental lead exposure risks. © 2010 The Authors. Journal of Paediatrics and Child Health © 2010 Paediatrics and Child Health Division (Royal Australasian College of Physicians).

Reducing lead in air and preventing childhood exposure near lead smelters: learning from the U.S. experience.

PubMed

Sullivan, Marianne

2015-05-01

Childhood lead exposure and poisoning near primary lead smelters continues in developed and developing countries. In the United States, the problem of lead poisoning in children caused by smelter emissions was first documented in the early 1970s. In 1978, Environmental Protection Agency set National Ambient Air Quality Standards for lead. Attainment of this lead standard in areas near operating lead smelters took twenty to thirty years. Childhood lead exposure and poisoning continued to occur after the lead National Ambient Air Quality Standards were set and before compliance was achieved. This article analyzes and discusses the factors that led to the eventual achievement of the 1978 lead National Ambient Air Quality Standards near primary smelters and the reduction of children's blood lead levels in surrounding communities. Factors such as federal and state regulation, monitoring of emissions, public health activities such as blood lead surveillance and health education, relocation of children, environmental group and community advocacy, and litigation all played a role. © The Author(s) 2015 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Evaluation of protective gloves and working techniques for reducing hand-arm vibration exposure in the workplace.

PubMed

Milosevic, Matija; McConville, Kristiina M Valter

2012-01-01

Operation of handheld power tools results in exposure to hand-arm vibrations, which over time lead to numerous health complications. The objective of this study was to evaluate protective equipment and working techniques for the reduction of vibration exposure. Vibration transmissions were recorded during different work techniques: with one- and two-handed grip, while wearing protective gloves (standard, air and anti-vibration gloves) and while holding a foam-covered tool handle. The effect was examined by analyzing the reduction of transmitted vibrations at the wrist. The vibration transmission was recorded with a portable device using a triaxial accelerometer. The results suggest large and significant reductions of vibration with appropriate safety equipment. Reductions of 85.6% were achieved when anti-vibration gloves were used. Our results indicated that transmitted vibrations were affected by several factors and could be measured and significantly reduced.

Cumulative Lead Exposure and Age-related Hearing Loss: The VA Normative Aging Study

PubMed Central

Park, Sung Kyun; Elmarsafawy, Sahar; Mukherjee, Bhramar; Spiro, Avron; Vokonas, Pantel S.; Nie, Huiling; Weisskopf, Marc G.; Schwartz, Joel; Hu, Howard

2010-01-01

Although lead has been associated with hearing loss in occupational settings and in children, little epidemiologic research has been conducted on the impact of cumulative lead exposure on age-related hearing loss in the general population. We determined whether bone lead levels, a marker of cumulative lead exposure, are associated with decreased hearing ability in 448 men from the Normative Aging Study, seen between 1962 and 1996 (2,264 total observations). Air conduction hearing thresholds were measured at 0.25 to 8 kHz and pure tone averages (PTA) (mean of 0.5, 1, 2 and 4 kHz) were computed. Tibia and patella lead levels were measured using K x-ray fluorescence between 1991 and 1996. In cross-sectional analyses, after adjusting for potential confounders including occupational noise, patella lead levels were significantly associated with poorer hearing thresholds at 2, 3, 4, 6 and 8 kHz and PTA. The odds of hearing loss significantly increased with patella lead levels. We also found significant positive associations between tibia lead and the rate change in hearing thresholds at 1, 2, and 8 kHz and PTA in longitudinal analyses. Our results suggest that chronic low-level lead exposure may be an important risk factor for age-related hearing loss and reduction of lead exposure could help prevent or delay development of age-related hearing loss. PMID:20638461

Oral Chromium Exposure and Toxicity

PubMed Central

Sun, Hong; Brocato, Jason

2015-01-01

Hexavalent chromium [Cr(VI)] is a known carcinogen when inhaled. However, inhalational exposure to Cr(VI) affects only a small portion of the population, mainly by occupational exposures. In contrast, oral exposure to Cr(VI) is widespread and affects many people throughout the globe. In 2008, the National Toxicology Program (NTP) released a 2-year study demonstrating that ingested Cr(VI) was carcinogenic in rats and mice. The effects of Cr(VI) oral exposure is mitigated by reduction in the gut, however a portion evades the reductive detoxification and reaches target tissues. Once Cr(VI) enters the cell, it ultimately gets reduced to Cr(III), which mediates its toxicity via induction of oxidative stress during the reduction while Cr intermediates react with protein and DNA. Cr(III) can form adducts with DNA that may lead to mutations. This review will discuss the potential adverse effects of oral exposure to Cr(VI) by presenting up-to-date human and animal studies, examining the underlying mechanisms that mediate Cr(VI) toxicity, as well as highlighting opportunities for future research. PMID:26231506

Analysis and reduction of the uncertainty of the assessment of children's lead exposure around an old mine.

PubMed

Glorennec, Philippe

2006-02-01

Exposure to lead is a special problem in children, because they are more highly exposed than adults and because this pollutant, which accumulates in the body, induces neurobehavioral and cognitive effects. The objective of this study was to determine the probability density of the lead exposure dose of a 2-year-old child around an old mine site and to analyze its uncertainties, especially those associated with the bioavailability of lead in soil. Children's exposure was estimated indirectly from environmental samples (soils, domestic dust, water, air) and parameters (volume inhaled, body weight, soil intake rate, water intake, dietary intake) from the literature. Uncertainty and variability were analyzed separately in a two-dimensional Monte Carlo simulation with Crystal Ball software. Exposure doses were simulated with different methods for accessing the bioavailability of lead in soil. The exposure dose per kilogram of body weight varied from 2 microg/kgday at the 5th percentile to 5.5 microg/kgday at the 95th percentile (and from 2 to 10 microg/kgday, respectively, when ignoring bioavailability). The principal factors of variation were dietary intake, soil concentrations, and soil ingestion. The principal uncertainties were associated with the level of soil ingestion and the bioavailability of lead. Reducing uncertainty about the bioavailability of lead in soil by taking into account information about the type of mineral made it possible to increase our degree of confidence (from 25% to more than 95%) that the median exposure dose does not exceed the Tolerable Daily Intake. Knowledge of the mineral very substantially increases the degree of confidence in estimates of children's lead exposure around an old mining site by reducing the uncertainty associated with lead's bioavailability.

Potential health risks to adults and children in the UK from exposure to dietary lead in gamebirds shot with lead ammunition.

PubMed

Green, R E; Pain, D J

2012-11-01

We estimate potential risks to human health in the UK from dietary exposure to lead from wild gamebirds killed by shooting. The main source of exposure to lead in Europe is now dietary. We used data on lead concentrations in UK gamebirds, from which gunshot had been removed following cooking to simulate human exposure to lead. We used UK food consumption and lead concentration data to evaluate the number of gamebird meals consumed weekly that would be expected, based upon published studies, to result in changes, over and above those resulting from exposure to lead in the base diet, in intelligence quotient (IQ), Systolic Blood Pressure and chronic kidney disease (CKD) considered in a recent opinion of the European Food Safety Authority (EFSA) to be significant at a population level and also in SAT test scores and in rates of spontaneous abortion. We found the consumption of <1 meal of game a week may be associated with a one point reduction in IQ in children and 1.2-6.5 gamebird meals per week may be associated with the other effects. These results should help to inform the development of appropriate responses to the risks from ingesting lead from ammunition in game in the UK and European Union (EU). Copyright © 2012 Elsevier Ltd. All rights reserved.

Lead in hawks, falcons and owls downstream from a mining site on the Coeur D'Alene river, Idaho

USGS Publications Warehouse

Henny, C.J.; Blus, L.J.; Hoffman, D.J.; Grove, R.A.

1994-01-01

Mining and smelting at Kellogg-Smelterville, Idaho, resulted in high concentrations of lead in Coeur d'Alene (CDA) River sediments and the floodplain downstream, where American Kestrels (Falco sparverius), Northern Harriers (Circus cyaneus), Red-tailed Hawks (Buteo jamaicensis), Great Horned Owls (Bubo virginianus), and Western Screech-owls (Otus kennicotti) nested. Nestling American Kestrels contained significantly higher (P=0.0012) blood lead concentrations along the CDA River (0.24 ?g/g, wet wt) than the nearby reference area (0.087 ?g/g). A 35% inhibition of blood *-aminolevulinic acid dehydratase (ALAD) in nestling Northern Harriers (P=0.0001), 55% in nestling American Kestrels (P=0.0001) and 81% in adult American Kestrels (P=0.0004) provided additional evidence of lead exposure in the CDA River population. In nestling American Kestrels and Northern Harriers, ALAD activity was negatively correlated with lead in blood. An earlier report on Ospreys (Pandion haliaetus) showed slightly less inhibition of ALAD than in American Kestrels, but no significant reduction in hemoglobin or hematocrit and no negative influence on production rates. The adult and nestling American Kestrels along the CDA River contained about twice as much blood lead as Ospreys during the same years (adult 0.46 vs. 0.20 ?g/g, and nestling 0.24 vs. 0.09 ?g/g), but adults showed a 7.5% reduction in hemoglobin (P=0.0356) and nestlings an 8.2% reduction in hemoglobin (P=0.0353) and a 5.8% reduction in hematocrit (P=0.0482). We did not observe raptor deaths related to lead, and although the production rate for American Kestrels was slightly lower along the CDA River, we found no significant negative relation between productivity and lead. Limited data on the other raptors provide evidence of exposure to lead along the CDA River. Several traits of raptors apparently reduce their potential for accumulating critical levels of lead which is primarily stored in bones of prey species.

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

Barr, J.H.; Silha, R.E.; Richards, A.G.

A report of the Radiation Protection Committee of the American Academy of Oral Roentgenology on recommendation for reducing exposure to patient and dentist during oral radiographic procedures is reviewed. The following aspects of the problem of exposure reduction are considered: max permissible exposures to operators and patients, sources of radiation in dental offices, recommended building materials to be used for wall construction (with their lead equivalents), and detailed statements of procedures for protecting operators and patients. (TCO)

Virtual reality in the treatment of persecutory delusions: randomised controlled experimental study testing how to reduce delusional conviction.

PubMed

Freeman, Daniel; Bradley, Jonathan; Antley, Angus; Bourke, Emilie; DeWeever, Natalie; Evans, Nicole; Černis, Emma; Sheaves, Bryony; Waite, Felicity; Dunn, Graham; Slater, Mel; Clark, David M

2016-07-01

Persecutory delusions may be unfounded threat beliefs maintained by safety-seeking behaviours that prevent disconfirmatory evidence being successfully processed. Use of virtual reality could facilitate new learning. To test the hypothesis that enabling patients to test the threat predictions of persecutory delusions in virtual reality social environments with the dropping of safety-seeking behaviours (virtual reality cognitive therapy) would lead to greater delusion reduction than exposure alone (virtual reality exposure). Conviction in delusions and distress in a real-world situation were assessed in 30 patients with persecutory delusions. Patients were then randomised to virtual reality cognitive therapy or virtual reality exposure, both with 30 min in graded virtual reality social environments. Delusion conviction and real-world distress were then reassessed. In comparison with exposure, virtual reality cognitive therapy led to large reductions in delusional conviction (reduction 22.0%, P = 0.024, Cohen's d = 1.3) and real-world distress (reduction 19.6%, P = 0.020, Cohen's d = 0.8). Cognitive therapy using virtual reality could prove highly effective in treating delusions. © The Royal College of Psychiatrists 2016.

Virtual reality in the treatment of persecutory delusions: randomised controlled experimental study testing how to reduce delusional conviction

PubMed Central

Freeman, Daniel; Bradley, Jonathan; Antley, Angus; Bourke, Emilie; DeWeever, Natalie; Evans, Nicole; Černis, Emma; Sheaves, Bryony; Waite, Felicity; Dunn, Graham; Slater, Mel; Clark, David M.

2016-01-01

Background Persecutory delusions may be unfounded threat beliefs maintained by safety-seeking behaviours that prevent disconfirmatory evidence being successfully processed. Use of virtual reality could facilitate new learning. Aims To test the hypothesis that enabling patients to test the threat predictions of persecutory delusions in virtual reality social environments with the dropping of safety-seeking behaviours (virtual reality cognitive therapy) would lead to greater delusion reduction than exposure alone (virtual reality exposure). Method Conviction in delusions and distress in a real-world situation were assessed in 30 patients with persecutory delusions. Patients were then randomised to virtual reality cognitive therapy or virtual reality exposure, both with 30 min in graded virtual reality social environments. Delusion conviction and real-world distress were then reassessed. Results In comparison with exposure, virtual reality cognitive therapy led to large reductions in delusional conviction (reduction 22.0%, P = 0.024, Cohen's d = 1.3) and real-world distress (reduction 19.6%, P = 0.020, Cohen's d = 0.8). Conclusion Cognitive therapy using virtual reality could prove highly effective in treating delusions. PMID:27151071

Recent Developments in Low-Level Lead Exposure and Intellectual Impairment in Children

PubMed Central

Koller, Karin; Brown, Terry; Spurgeon, Anne; Levy, Len

2004-01-01

In the last decade children’s blood lead levels have fallen significantly in a number of countries, and current mean levels in developed countries are in the region of 3 μg/dL. Despite this reduction, childhood lead poisoning continues to be a major public health problem for certain at-risk groups of children, and concerns remain over the effects of lead on intellectual development in infants and children. The evidence for lowered cognitive ability in children exposed to lead has come largely from prospective epidemiologic studies. The current World Health Organization/Centers for Disease Control and Prevention blood level of concern reflects this and stands at 10 μg/dL. However, a recent study on a cohort of children whose lifetime peak blood levels were consistently < 10 μg/dL has extended the association of blood lead and intellectual impairment to lower levels of lead exposure and suggests there is no safety margin at existing exposures. Because of the importance of this finding, we reviewed this study in detail along with other recent developments in the field of low-level lead exposure and children’s cognitive development. We conclude that these findings are important scientifically, and efforts should continue to reduce childhood exposure. However, from a public health perspective, exposure to lead should be seen within the many other risk factors impacting on normal childhood development, in particular the influence of the learning environment itself. Current lead exposure accounts for a very small amount of variance in cognitive ability (1–4%), whereas social and parenting factors account for 40% or more. PMID:15198918

Electron-beam-induced topographical, chemical, and structural patterning of amorphous titanium oxide films.

PubMed

Kern, P; Müller, Y; Patscheider, J; Michler, J

2006-11-30

Electrolytically deposited amorphous TiO2 films on steel are remarkably sensitive to electron beam (e-beam) irradiation at moderate energies at 20 keV, resulting in controlled local oxide reduction and crystallization, opening the possibility for local topographical, chemical, and structural modifications within a biocompatible, amorphous, and semiconducting matrix. The sensitivity is shown to vary significantly with the annealing temperature of as-deposited films. Well-defined irradiation conditions in terms of probe current IP (5 microA) and beam size were achieved with an electron probe microanalyzer. As shown by atomic force and optical microscopy, micro-Raman spectroscopy, wavelength-dispersive X-ray (WDX), and Auger analyses, e-beam exposure below 1 Acm-2 immediately leads to electron-stimulated oxygen desorption, resulting in a well-defined volume loss primarily limited to the irradiated zone under the electron probe and in a blue color shift in this zone because of the presence of Ti2O3. Irradiation at 5 Acm(-2) (IP = 5 microA) results in local crystallization into anatase phase within 1 s of exposure and in reduction to TiO after an extended exposure of 60 s. Further reduction to the metallic state could be observed after 60 s of exposure at approximately 160 Acm(-2). The local reduction could be qualitatively sensed with WDX analysis and Auger line scans. An estimation of the film temperature in the beam center indicates that crystallization occurs at less than 150 degrees C, well below the atmospheric crystallization temperature of the present films. The high e-beam sensitivity in combination with the well-defined volume loss from oxygen desorption allows for precise electron lithographic topographical patterning of the present oxides. Irradiation effects leading to the observed reduction and crystallization phenomena under moderate electron energies are discussed.

Updating about reductions of air and blood lead concentrations in Turin, Italy, following reductions in the lead content of gasoline.

PubMed

Bono, R; Pignata, C; Scursatone, E; Rovere, R; Natale, P; Gilli, G

1995-07-01

Considering its well-know toxicity and the chronic human exposure to lead, international law-makers enforced some directives or laws calling for the reduction of lead content of gasoline. All of these legislative acts aimed to reduce health risks for the general population. The aim of this study was to consider the effectiveness of these laws on air lead levels and consequently on blood lead levels in a randomly selected urban Italian population. In particular, these markers were analyzed over the course of several years, corresponding to the periods just before and after enforcements of the reductions of lead in petrol. Data presented point out some considerations: (1) enforcement of legislative measures concerning the reduction of lead in petrol has reduced atmospheric levels of lead. This result demonstrates a major environmental success in primary prevention efforts. (2) This success is clear especially considering that the actual Pb-B levels can be extended to the urbanized populations. Pb-B levels were consistently higher for drinkers, for older adults, and for males. The mean of Pb-B level for the present urbanized population is higher than the U.S. overall population (6.4 vs 3 microgram/dl). This difference can be also explained considering the different historical period of enforcement of the restriction laws.

CT Fluoroscopy Shielding: Decreases in Scattered Radiation for the Patient and Operator

PubMed Central

Neeman, Ziv; Dromi, Sergio A.; Sarin, Shawn; Wood, Bradford J.

2008-01-01

PURPOSE High-radiation exposure occurs during computed tomographic (CT) fluoroscopy. Patient and operator doses during thoracic and abdominal interventional procedures were studied in the present experiment, and a novel shielding device to reduce exposure to the patient and operator was evaluated. MATERIALS AND METHODS With a 16-slice CT scanner in CT fluoroscopy mode (120 kVp, 30 mA), surface dosimetry was performed on adult and pediatric phantoms. The shielding was composed of tungsten antimony in the form of a lightweight polymer sheet. Doses to the patient were measured with and without shielding for thoracic and abdominal procedures. Doses to the operator were recorded with and without phantom, gantry, and table shielding in place. Double-layer lead-free gloves were used by the operator during the procedures. RESULTS Tungsten antimony shielding adjacent to the scan plane resulted in a maximum dose reduction of 92.3% to the patient. Maximum 85.6%, 93.3%, and 85.1% dose reductions were observed for the operator’s torso, gonads, and hands, respectively. The use of double-layer lead-free gloves resulted in a maximum radiation dose reduction of 97%. CONCLUSIONS Methods to reduce exposure during CT fluoroscopy are effective and should be searched for. Significant reduction in radiation doses to the patient and operator can be accomplished with tungsten antimony shielding. PMID:17185699

Caregivers’ interest in using smokeless tobacco products: Novel methods that may reduce children’s exposure to secondhand smoke

PubMed Central

Wagener, Theodore L; Tackett, Alayna P; Borrelli, Belinda

2017-01-01

The study examined caregivers’ interest in using potentially reduced exposure tobacco products for smoking cessation, reduction, and to help them not smoke in places such as around their child, as all three methods would potentially lead to reduced secondhand smoke exposure for their children. A sample of 136 caregivers completed carbon monoxide testing to assess smoking status and a brief survey. Few caregivers had ever used potentially reduced exposure tobacco products (<1%), but a majority were interested in trying them as means of smoking reduction (54%), to quit/stay quit from smoking (51%), and to help them not smoke around their child or in the home (55%). Caregivers less motivated to quit smoking and with no home smoking ban were more interested in using potentially reduced exposure tobacco products to help them quit/stay quit from smoking (p < .05). PMID:25845835

Caregivers' interest in using smokeless tobacco products: Novel methods that may reduce children's exposure to secondhand smoke.

PubMed

Wagener, Theodore L; Tackett, Alayna P; Borrelli, Belinda

2016-10-01

The study examined caregivers' interest in using potentially reduced exposure tobacco products for smoking cessation, reduction, and to help them not smoke in places such as around their child, as all three methods would potentially lead to reduced secondhand smoke exposure for their children. A sample of 136 caregivers completed carbon monoxide testing to assess smoking status and a brief survey. Few caregivers had ever used potentially reduced exposure tobacco products (<1%), but a majority were interested in trying them as means of smoking reduction (54%), to quit/stay quit from smoking (51%), and to help them not smoke around their child or in the home (55%). Caregivers less motivated to quit smoking and with no home smoking ban were more interested in using potentially reduced exposure tobacco products to help them quit/stay quit from smoking (p < .05). © The Author(s) 2015.

The transition to non-lead rifle ammunition in Denmark: National obligations and policy considerations.

PubMed

Kanstrup, Niels; Thomas, Vernon G; Krone, Oliver; Gremse, Carl

2016-09-01

The issue of Denmark regulating use of lead-free rifle ammunition because of potential risks of lead exposure in wildlife and humans was examined from a scientific and objective policy perspective. The consequences of adopting or rejecting such regulation were identified. Denmark is obliged to examine this topic because of its national policy on lead reduction, its being a Party to the UN Bonn Convention on Migratory Species, and its role in protecting White-tailed Sea Eagles (Haliaeetus albicilla), a species prone to lead poisoning from lead ingestion. Lead-free bullets suited for deer hunting are available at comparable cost to lead bullets, and have been demonstrated to be as effective. National adoption of lead-free bullets would complete the Danish transition to lead-free ammunition use. It would reduce the risk of lead exposure to scavenging wildlife, and humans who might eat lead-contaminated wild game meat. Opposition from hunting organizations would be expected.

Test plan 241-C-103 natural breathing characteristics evaluation using the ultra sensitive flowmeter

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

Hertelendy, N.A.

1995-02-13

To facilitate the reduction of worker exposure to hazardous fumes and vapors, it is imperative to characterize and measure flows out of waste tanks that breathe due to atmospheric pressure changes. These measurements will lead to a better understanding of how these tanks breathe and thus will aid in better worker exposure control at lower cost.

Glycogen metabolism in brain and neurons - astrocytes metabolic cooperation can be altered by pre- and neonatal lead (Pb) exposure.

PubMed

Baranowska-Bosiacka, Irena; Falkowska, Anna; Gutowska, Izabela; Gąssowska, Magdalena; Kolasa-Wołosiuk, Agnieszka; Tarnowski, Maciej; Chibowska, Karina; Goschorska, Marta; Lubkowska, Anna; Chlubek, Dariusz

2017-09-01

Lead (Pb) is an environmental neurotoxin which particularly affects the developing brain but the molecular mechanism of its neurotoxicity still needs clarification. The aim of this paper was to examine whether pre- and neonatal exposure to Pb (concentration of Pb in rat offspring blood below the "threshold level") may affect the brain's energy metabolism in neurons and astrocytes via the amount of available glycogen. We investigated the glycogen concentration in the brain, as well as the expression of the key enzymes involved in glycogen metabolism in brain: glycogen synthase 1 (Gys1), glycogen phosphorylase (PYGM, an isoform active in astrocytes; and PYGB, an isoform active in neurons) and phosphorylase kinase β (PHKB). Moreover, the expression of connexin 43 (Cx43) was evaluated to analyze whether Pb poisoning during the early phase of life may affect the neuron-astrocytes' metabolic cooperation. This work shows for the first time that exposure to Pb in early life can impair brain energy metabolism by reducing the amount of glycogen and decreasing the rate of its metabolism. This reduction in brain glycogen level was accompanied by a decrease in Gys1 expression. We noted a reduction in the immunoreactivity and the gene expression of both PYGB and PYGM isoform, as well as an increase in the expression of PHKB in Pb-treated rats. Moreover, exposure to Pb induced decrease in connexin 43 immunoexpression in all the brain structures analyzed, both in astrocytes as well as in neurons. Our data suggests that exposure to Pb in the pre- and neonatal periods results in a decrease in the level of brain glycogen and a reduction in the rate of its metabolism, thereby reducing glucose availability, which as a further consequence may lead to the impairment of brain energy metabolism and the metabolic cooperation between neurons and astrocytes. Copyright © 2017 Elsevier B.V. All rights reserved.

Evaluation of radiation exposure with Tru-Align intraoral rectangular collimation system using OSL dosimeters.

PubMed

Goren, Arthur D; Bonvento, Michael J; Fernandez, Thomas J; Abramovitch, Kenneth; Zhang, Wenjian; Roe, Nadine; Seltzer, Jared; Steinberg, Mitchell; Colosi, Dan C

2011-03-01

A pilot study to compare radiation exposure with the Tru-Align rectangular collimation system to round collimation exposures was undertaken. Radiation exposure at various points within the cross sections of the collimators and entrance, intraoral and exit dose measurements were measured using InLight OSL dosimeters. Overall dose reduction with the use of the rectangular collimation system was estimated by taking into account the ratios of collimator openings and the average radiation exposure at the measurement points. Use of the Tru-Align system resulted in an average radiation exposure within the perimeter of the projected outline of the rectangular collimator of 36.1 mR, compared to 148.5 mR with the round collimator. Our calculations indicate a dose reduction by a factor of approximately 3.2 in the case of the Tru-Align system compared to round collimation. The Tru-Align system was easy to use, but in some situations failed to allow Xray coverage of the entire surface of the image receptor, leading to cone cuts.

Secrets of the lac operon. Glucose hysteresis as a mechanism in dietary restriction, aging and disease.

PubMed

Mobbs, Charles V; Mastaitis, Jason W; Zhang, Minhua; Isoda, Fumiko; Cheng, Hui; Yen, Kelvin

2007-01-01

Elevated blood glucose associated with diabetes produces progressive and apparently irreversible damage to many cell types. Conversely, reduction of glucose extends life span in yeast, and dietary restriction reduces blood glucose. Therefore it has been hypothesized that cumulative toxic effects of glucose drive at least some aspects of the aging process and, conversely, that protective effects of dietary restriction are mediated by a reduction in exposure to glucose. The mechanisms mediating cumulative toxic effects of glucose are suggested by two general principles of metabolic processes, illustrated by the lac operon but also observed with glucose-induced gene expression. First, metabolites induce the machinery of their own metabolism. Second, induction of gene expression by metabolites can entail a form of molecular memory called hysteresis. When applied to glucose-regulated gene expression, these two principles suggest a mechanism whereby repetitive exposure to postprandial excursions of glucose leads to an age-related increase in glycolytic capacity (and reduction in beta-oxidation of free fatty acids), which in turn leads to an increased generation of oxidative damage and a decreased capacity to respond to oxidative damage, independent of metabolic rate. According to this mechanism, dietary restriction increases life span and reduces pathology by reducing exposure to glucose and therefore delaying the development of glucose-induced glycolytic capacity.

Reducing radiation exposure during CRT implant procedures: early experience with a sensor-based navigation system.

PubMed

Thibault, Bernard; Andrade, Jason G; Dubuc, Marc; Talajic, Mario; Guerra, Peter G; Dyrda, Katia; Macle, Laurent; Rivard, Léna; Roy, Denis; Mondésert, Blandine; Khairy, Paul

2015-01-01

Cardiac resynchronization therapy (CRT) implant procedures are often complex and prolonged, resulting in significant ionizing radiation (IR) exposure to the patient and operator. We report our early experience working with a novel sensor-based electromagnetic tracking system (MediGuide™, MDG, St. Jude Medical Inc., St. Paul, MN, USA), in terms of procedural IR exposure reduction. Information regarding patient demographics, procedural details, procedural duration, and IR exposure were prospectively collected on 130 consecutive CRT procedures performed between January 2013 and January 2014. Sixty procedures were performed with MDG guidance, and 70 were performed without MDG guidance. Despite a nonsignificant trend toward shorter procedure duration with the use of MDG (120 minutes vs 138 minutes with non-MDG, P = 0.088), a 66% reduction in total IR exposure (median 769 μGray · m(2) vs 2,608 μGray · m(2), P < 0.001) was found. This reduction was primarily driven by a >90% reduction in IR dose required to cannulate the coronary sinus (median 80 μGray · m(2) vs 922 μGray · m(2), P < 0.001), and to a lesser extent from a reduction in IR dose required for LV lead placement (median 330 μGray·m(2) vs 737 μGray · m(2), P = 0.059). In addition, a significant learning curve effect was observed with a significantly shorter procedural duration for the last 15 cases compared to the first 15 cases (median 98 minutes vs 175 minutes, P < 0.001). The nonfluoroscopic MDG positioning system is associated with a dramatic reduction in exposure to IR during CRT implant procedures, with a 90% decrease in the IR dose required to cannulate the coronary sinus. A steep learning curve was quantified. ©2014 Wiley Periodicals, Inc.

Use what you can: storage, abstraction processes, and perceptual adjustments help listeners recognize reduced forms

PubMed Central

Poellmann, Katja; Mitterer, Holger; McQueen, James M.

2014-01-01

Three eye-tracking experiments tested whether native listeners recognized reduced Dutch words better after having heard the same reduced words, or different reduced words of the same reduction type and whether familiarization with one reduction type helps listeners to deal with another reduction type. In the exposure phase, a segmental reduction group was exposed to /b/-reductions (e.g., minderij instead of binderij, “book binder”) and a syllabic reduction group was exposed to full-vowel deletions (e.g., p'raat instead of paraat, “ready”), while a control group did not hear any reductions. In the test phase, all three groups heard the same speaker producing reduced-/b/ and deleted-vowel words that were either repeated (Experiments 1 and 2) or new (Experiment 3), but that now appeared as targets in semantically neutral sentences. Word-specific learning effects were found for vowel-deletions but not for /b/-reductions. Generalization of learning to new words of the same reduction type occurred only if the exposure words showed a phonologically consistent reduction pattern (/b/-reductions). In contrast, generalization of learning to words of another reduction type occurred only if the exposure words showed a phonologically inconsistent reduction pattern (the vowel deletions; learning about them generalized to recognition of the /b/-reductions). In order to deal with reductions, listeners thus use various means. They store reduced variants (e.g., for the inconsistent vowel-deleted words) and they abstract over incoming information to build up and apply mapping rules (e.g., for the consistent /b/-reductions). Experience with inconsistent pronunciations leads to greater perceptual flexibility in dealing with other forms of reduction uttered by the same speaker than experience with consistent pronunciations. PMID:24910622

Blood lead in the 21st Century: The sub-microgram challenge

PubMed Central

Amaya, Maria A; Jolly, Kevin W; Pingitore, Nicholas E

2010-01-01

In the US the dominant sources of lead through much of the 20th Century (eg, vehicular emissions, plumbing, household paint) have been significantly diminished. The reductions in adult and pediatric average blood lead levels in the US have been extraordinary. Progress continues: the US Environmental Protection Agency recently developed a new air standard for lead. In the 21st Century, the average blood lead level in a society may be seen as a marker of the status of their public’s health. However, the threat of lead exposure remains a significant public health problem among subpopulation groups in the US and in many less developed countries. This paper examines some of the specific issues involved in the reduction of blood lead in a post-industrial era. These involve the control of the remaining exogenous primary sources, both general (eg, industrial emissions) and specific (eg, at-risk occupations), exogenous secondary sources (eg, contaminated urban soils, legacy lead-based paints), an endogenous source (ie, cumulative body lead burden) and emergent sources. PMID:22282686

Childhood lead exposure in France: benefit estimation and partial cost-benefit analysis of lead hazard control

PubMed Central

2011-01-01

Background Lead exposure remains a public health concern due to its serious adverse effects, such as cognitive and behavioral impairment: children younger than six years of age being the most vulnerable population. In Europe, the lead-related economic impacts have not been examined in detail. We estimate the annual costs in France due to childhood exposure and, through a cost benefit analysis (CBA), aim to assess the expected social and economic benefits of exposure abatement. Methods Monetary benefits were assessed in terms of avoided national costs. We used results from a 2008 survey on blood-lead (B-Pb) concentrations in French children aged one to six years old. Given the absence of a threshold concentration being established, we performed a sensitivity analysis assuming different hypothetical threshold values for toxicity above 15 μg/L, 24 μg/L and 100 μg/L. Adverse health outcomes of lead exposure were translated into social burden and economic costs based on literature data from literature. Direct health benefits, social benefits and intangible avoided costs were included. Costs of pollutant exposure control were partially estimated in regard to homes lead-based paint decontamination, investments aiming at reducing industrial lead emissions and removal of all lead drinking water pipes. Results The following overall annual benefits for the three hypothetical thresholds values in 2008 are: €22.72 billion, €10.72 billion and €0.44 billion, respectively. Costs from abatement ranged from €0.9 billion to 2.95 billion/year. Finally, from a partial CBA of lead control in soils and dust the estimates of total net benefits were € 3.78 billion, € 1.88 billion and €0.25 billion respectively for the three hypothesized B-Pb effect values. Conclusions Prevention of childhood lead exposure has a high social benefit, due to reduction of B-Pb concentrations to levels below 15 μg/L or 24 μg/L, respectively. Reducing only exposures above 100 μg/L B-Pb has little economic impact due to the small number of children who now exhibit such high exposure levels. Prudent public policies would help avoiding future medical interventions, limit the need for special education and increase future productivity, and hence lifetime income for children exposed to lead. PMID:21599937

A leaded apron for use in panoramic dental radiography.

PubMed

Whitcher, B L; Gratt, B M; Sickles, E A

1980-05-01

The leaded aprons currently available for use during dental radiography do not protect the thyroid gland from radiation. Conventional aprons may produce artifacts when used with panoramic dental x-ray units. This study measures the dose reduction obtained with an experimental leaded apron designed for use with panoramic dental x-ray units. Skin exposures measured at the thyroid and at the sternum were reduced with the use of the apron. Films produced during the study were free from apron artifacts.

Approach for Estimating Exposures and Incremental Health ...

EPA Pesticide Factsheets

Approach for Estimating Exposures and Incremental Health Effects from Lead During Renovation, Repair, and Painting Activities in Public and Commercial Buildings” (Technical Approach Document). Also available for public review and comment are two supplementary documents: the detailed appendices for the Technical Approach Document and a supplementary report entitled “Developing a Concentration-Response Function for Pb Exposure and Cardiovascular Disease-Related Mortality.” Together, these documents describes an analysis for estimating exposures and incremental health effects created by renovations of public and commercial buildings (P&CBs). This analysis could be used to identify and evaluate hazards from renovation, repair, and painting activities in P&CBs. A general overview of how this analysis can be used to inform EPA’s hazard finding is described in the Framework document that was previously made available for public comment (79 FR 31072; FRL9910-44). The analysis can be used in any proposed rulemaking to estimate the reduction in deleterious health effects that would result from any proposed regulatory requirements to mitigate exposure from P&CB renovation activities. The Technical Approach Document describes in detail how the analyses under this approach have been performed and presents the results – expected changes in blood lead levels and health effects due to lead exposure from renovation activities.

Widespread exposure to lead affects the body condition of free-living whooper swans Cygnus cygnus wintering in Britain.

PubMed

Newth, J L; Rees, E C; Cromie, R L; McDonald, R A; Bearhop, S; Pain, D J; Norton, G J; Deacon, C; Hilton, G M

2016-02-01

Lead poisoning, through the ingestion of spent lead gunshot, is an established cause of morbidity and mortality in waterbirds globally, but the thresholds at which blood levels begin to affect the physiology of birds in the wild are less well known. Here we determine the prevalence of lead exposure in whooper swans and, for the first time, identify the level of blood lead associated with initial reductions in body condition. Blood lead elevated above background levels (i.e. >20 μg dL(-1)) was found in 41.7% (125/300) of swans tested. Blood lead was significantly negatively associated with winter body condition when levels were ≥44 μg dL(-1) (27/260 = 10%). Our findings indicating that sub-lethal impacts of lead on body condition occur at the lower end of previously established clinical thresholds and that a relatively high proportion of individuals in this population may be affected, reaffirm the importance of reducing contamination of the environment with lead shot. Copyright © 2015 Elsevier Ltd. All rights reserved.

Childhood Lead Exposure in the Palestinian Authority, Israel, and Jordan: Results from the Middle Eastern Regional Cooperation Project, 1996–2000

PubMed Central

Safi, Jamal; Fischbein, Alf; Haj, Sameer El; Sansour, Ramzi; Jaghabir, Madi; Hashish, Mohammed Abu; Suleiman, Hassan; Safi, Nimer; Abu-Hamda, Abed; Witt, Joyce K.; Platkov, Efim; Reingold, Steven; Alayyan, Amber; Berman, Tamar; Bercovitch, Matti; Choudhri, Yogesh; Richter, Elihu D.

2006-01-01

In the Middle East, the major sources of lead exposure have been leaded gasoline, lead-contaminated flour from traditional stone mills, focal exposures from small battery plants and smelters, and kohl (blue color) in cosmetics. In 1998–2000, we measured blood lead (PbB) levels in children 2–6 years of age in Israel, Jordan, and the Palestinian Authority (n = 1478), using a fingerstick method. Mean (peak; percentage > 10 μg/dL) PbB levels in Israel (n = 317), the West Bank (n = 344), Jordan (n = 382), and Gaza (n = 435) were 3.2 μg/dL (18.2; 2.2%), 4.2 μg/dL (25.7; 5.2%), 3.2 μg/dL (39.3; < 1%), and 8.6 μg/dL (> 80.0; 17.2%), respectively. High levels in Gaza were all among children living near a battery factory. The findings, taken together with data on time trends in lead emissions and in PbB in children in previous years, indicate the benefits from phasing out of leaded gasoline but state the case for further reductions and investigation of hot spots. The project demonstrated the benefits of regional cooperation in planning and carrying out a jointly designed project. PMID:16759995

Assessment of lead exposure in schoolchildren from Jakarta.

PubMed Central

Heinze, I; Gross, R; Stehle, P; Dillon, D

1998-01-01

Children attending schools in urban areas with high traffic density are a high risk group for lead poisoning. We assessed the magnitude of lead exposure in schoolchildren from Jakarta by analyzing blood lead concentrations and biomarkers of heme biosynthesis. A total of 131 children from four public elementary schools in Jakarta (two in the southern district and two in the central district) were enrolled in the study. To evaluate lead pollution in each area, soil samples and tap water were collected. The mean blood lead concentration was higher in the central district than in the southern district (8.3 +/- 2.8 vs. 6.9 +/- 3.5 microg/100 ml; p<0.05); 26.7% of the children had lead levels greater than 10 microg/100 ml. In 24% of the children, zinc protoporphyrin concentrations were over 70 micromol/mol hemoglobin; in 17% of the samples, hemoglobin was less than 11 g/100 ml. All other values were within the physiological range. Blood lead concentration and hematological biomarkers were not correlated. Analyses of tap water revealed lead values under 0. 01 mg/l; lead contamination of soil ranged from 77 to 223 ppm. Our data indicate that Indonesian children living in urban areas are at increased risk for blood lead levels above the actual acceptable limit. Activities to reduce pollution (e.g., reduction of lead in gasoline) and continuous monitoring of lead exposure are strongly recommended. Images Figure 1 PMID:9681978

Influence of grid control and object detection on radiation exposure and image quality using mobile C-arms - first results.

PubMed

Gosch, D; Ratzmer, A; Berauer, P; Kahn, T

2007-09-01

The objective of this study was to examine the extent to which the image quality on mobile C-arms can be improved by an innovative exposure rate control system (grid control). In addition, the possible dose reduction in the pulsed fluoroscopy mode using 25 pulses/sec produced by automatic adjustment of the pulse rate through motion detection was to be determined. As opposed to conventional exposure rate control systems, which use a measuring circle in the center of the field of view, grid control is based on a fine mesh of square cells which are overlaid on the entire fluoroscopic image. The system uses only those cells for exposure control that are covered by the object to be visualized. This is intended to ensure optimally exposed images, regardless of the size, shape and position of the object to be visualized. The system also automatically detects any motion of the object. If a pulse rate of 25 pulses/sec is selected and no changes in the image are observed, the pulse rate used for pulsed fluoroscopy is gradually reduced. This may decrease the radiation exposure. The influence of grid control on image quality was examined using an anthropomorphic phantom. The dose reduction achieved with the help of object detection was determined by evaluating the examination data of 146 patients from 5 different countries. The image of the static phantom made with grid control was always optimally exposed, regardless of the position of the object to be visualized. The average dose reduction when using 25 pulses/sec resulting from object detection and automatic down-pulsing was 21 %, and the maximum dose reduction was 60 %. Grid control facilitates C-arm operation, since optimum image exposure can be obtained independently of object positioning. Object detection may lead to a reduction in radiation exposure for the patient and operating staff.

Effectiveness of action to reduce exposure of free-ranging California condors in Arizona and Utah to lead from spent ammunition.

PubMed

Green, Rhys E; Hunt, W Grainger; Parish, Christopher N; Newton, Ian

2008-01-01

California condors (Gymnogyps californianus) released into the wild in Arizona ranged widely in Arizona and Utah. Previous studies have shown that the blood lead concentrations of many of the birds rise because of ingestion of spent lead ammunition. Condors were routinely recaptured and treated to reduce their lead levels as necessary but, even so, several died from lead poisoning. We used tracking data from VHF and satellite tags, together with the results of routine testing of blood lead concentrations, to estimate daily changes in blood lead level in relation to the location of each bird. The mean daily increment in blood lead concentration depended upon both the location of the bird and the time of year. Birds that spent time during the deer hunting season in two areas in which deer were shot with lead ammunition (Kaibab Plateau (Arizona) and Zion (Utah)) were especially likely to have high blood lead levels. The influence upon blood lead level of presence in a particular area declined with time elapsed since the bird was last there. We estimated the daily blood lead level for each bird and its influence upon daily mortality rate from lead poisoning. Condors with high blood lead over a protracted period were much more likely to die than birds with low blood lead or short-term elevation. We simulated the effect of ending the existing lead exposure reduction measures at Kaibab Plateau, which encourage the voluntary use of non-lead ammunition and removal of gut piles of deer and elk killed using lead ammunition. The estimated mortality rate due to lead in the absence of this program was sufficiently high that the condor population would be expected to decline rapidly. The extension of the existing lead reduction program to cover Zion (Utah), as well as the Kaibab plateau, would be expected to reduce mortality caused by lead substantially and allow the condor population to increase.

Effectiveness of Action to Reduce Exposure of Free-Ranging California Condors in Arizona and Utah to Lead from Spent Ammunition

PubMed Central

Green, Rhys E.; Hunt, W. Grainger; Parish, Christopher N.; Newton, Ian

2008-01-01

California condors (Gymnogyps californianus) released into the wild in Arizona ranged widely in Arizona and Utah. Previous studies have shown that the blood lead concentrations of many of the birds rise because of ingestion of spent lead ammunition. Condors were routinely recaptured and treated to reduce their lead levels as necessary but, even so, several died from lead poisoning. We used tracking data from VHF and satellite tags, together with the results of routine testing of blood lead concentrations, to estimate daily changes in blood lead level in relation to the location of each bird. The mean daily increment in blood lead concentration depended upon both the location of the bird and the time of year. Birds that spent time during the deer hunting season in two areas in which deer were shot with lead ammunition (Kaibab Plateau (Arizona) and Zion (Utah)) were especially likely to have high blood lead levels. The influence upon blood lead level of presence in a particular area declined with time elapsed since the bird was last there. We estimated the daily blood lead level for each bird and its influence upon daily mortality rate from lead poisoning. Condors with high blood lead over a protracted period were much more likely to die than birds with low blood lead or short-term elevation. We simulated the effect of ending the existing lead exposure reduction measures at Kaibab Plateau, which encourage the voluntary use of non-lead ammunition and removal of gut piles of deer and elk killed using lead ammunition. The estimated mortality rate due to lead in the absence of this program was sufficiently high that the condor population would be expected to decline rapidly. The extension of the existing lead reduction program to cover Zion (Utah), as well as the Kaibab plateau, would be expected to reduce mortality caused by lead substantially and allow the condor population to increase. PMID:19107211

PROPYLTHIOURACIL (PTU)-INDUCED HYPOTHYROIDISM REDUCES FIELD POTENTIAL AMPLITUDE BUT DOES NOT IMPAIR DENTATE GYRUS LTP IN VIVO.

EPA Science Inventory

Developmental exposure to hypothyroid-inducing agents leads to reductions in body weight, alterations in hippocampal structure, and impaired performance on a variety of behavioral learning tasks. Electrophysiological properties of the hippocampus in hypothyroid animals, however...

Exposure to arsenic and lead of children living near a copper-smelter in San Luis Potosi, Mexico: Importance of soil contamination for exposure of children.

PubMed

Carrizales, Leticia; Razo, Israel; Téllez-Hernández, Jesús I; Torres-Nerio, Rocío; Torres, Arturo; Batres, Lilia E; Cubillas, Ana-Cristina; Díaz-Barriga, Fernando

2006-05-01

The objective of this study was to assess the levels of soil contamination and child exposure in areas next to a primary smelter (arsenic-copper metallurgical) located in the community of Morales in San Luis Potosi, Mexico. In Morales, 90% of the soil samples studied in this work were above 400 mg/kg of lead, and above 100 mg/kg of arsenic, which are guidelines recommended by the United States Environmental Protection Agency (EPA). Bioaccessibility of these metals was studied in vitro in 10 soil samples; the median values of bioaccessibility obtained in these samples were 46.5% and 32.5% for arsenic and lead. Since the concentrations of arsenic and lead in soil were above normal values, and taking into account the bioaccessibility results, exposure to these metals was evaluated in children. Regarding lead, children aged 3-6 years had the highest mean blood lead levels; furthermore, 90% of them had concentrations above 10 microg/dl (CDC's action level). Total urinary arsenic was higher in children aged 8-9 yr; however, the percentage of children with concentrations above 50 microg/g creatinine (CDC's action level) or 100 microg/g creatinine (World Health Organization [WHO] action level) was similar among different age groups. Using the EPAs integrated exposure uptake biokinetic model for lead in children (IEUBK), we estimated that 87% of the total lead in blood is obtained from the soil/dust pathway. The exposure dose to arsenic, estimated for the children living in Morales using Monte Carlo analysis and the arsenic concentrations found in soil, was above the EPA's reference dose. With all these results, it is evident that studies are needed in order to identify adverse health effects in children living in Morales; nevertheless, it is more important to develop a risk reduction program as soon as possible.

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

PubMed

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

2017-06-01

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

Reduced risk estimations after remediation of lead (Pb) in drinking water at two US school districts.

PubMed

Triantafyllidou, Simoni; Le, Trung; Gallagher, Daniel; Edwards, Marc

2014-01-01

The risk of students to develop elevated blood lead from drinking water consumption at schools was assessed, which is a different approach from predictions of geometric mean blood lead levels. Measured water lead levels (WLLs) from 63 elementary schools in Seattle and 601 elementary schools in Los Angeles were acquired before and after voluntary remediation of water lead contamination problems. Combined exposures to measured school WLLs (first-draw and flushed, 50% of water consumption) and home WLLs (50% of water consumption) were used as inputs to the Integrated Exposure Uptake Biokinetic (IEUBK) model for each school. In Seattle an average 11.2% of students were predicted to exceed a blood lead threshold of 5 μg/dL across 63 schools pre-remediation, but predicted risks at individual schools varied (7% risk of exceedance at a "low exposure school", 11% risk at a "typical exposure school", and 31% risk at a "high exposure school"). Addition of water filters and removal of lead plumbing lowered school WLL inputs to the model, and reduced the predicted risk output to 4.8% on average for Seattle elementary students across all 63 schools. The remnant post-remediation risk was attributable to other assumed background lead sources in the model (air, soil, dust, diet and home WLLs), with school WLLs practically eliminated as a health threat. Los Angeles schools instead instituted a flushing program which was assumed to eliminate first-draw WLLs as inputs to the model. With assumed benefits of remedial flushing, the predicted average risk of students to exceed a BLL threshold of 5 μg/dL dropped from 8.6% to 6.0% across 601 schools. In an era with increasingly stringent public health goals (e.g., reduction of blood lead safety threshold from 10 to 5 μg/dL), quantifiable health benefits to students were predicted after water lead remediation at two large US school systems. © 2013.

Toxicants in folk remedies: Implications of elevated blood lead in an American-born infant due to imported diaper powder

USGS Publications Warehouse

Karwowski, Mateusz P.; Morman, Suzette A.; Plumlee, Geoffrey S.; Law, Terence; Kellogg, Mark; Woolf, Alan D.

2016-01-01

Though most childhood lead exposure in the USA results from ingestion of lead-based paint dust, non-paint sources are increasingly implicated. We present interdisciplinary findings from and policy implications of a case of elevated blood lead (13–18 mcg/dL, reference level <5 mcg/dL) in a 9-month-old infant, linked to a non-commercial Malaysian folk diaper powder. Analyses showed the powder contains 62 % lead by weight (primarily lead oxide) and elevated antimony [1000 parts per million (ppm)], arsenic (55 ppm), bismuth (110 ppm), and thallium (31 ppm). These metals are highly bioaccessible in simulated gastric fluids, but only slightly bioaccessible in simulated lung fluids and simulated urine, suggesting that the primary lead exposure routes were ingestion via hand-mouth transmission and ingestion of inhaled dusts cleared from the respiratory tract. Four weeks after discontinuing use of the powder, the infant’s venous blood lead level was 8 mcg/dL. Unregulated, imported folk remedies can be a source of toxicant exposure. Additional research on import policy, product regulation, public health surveillance, and culturally sensitive risk communication is needed to develop efficacious risk reduction strategies in the USA. The more widespread use of contaminated folk remedies in the countries from which they originate is a substantial concern.

Toxicants in folk remedies: implications of elevated blood lead in an American-born infant due to imported diaper powder.

PubMed

Karwowski, Mateusz P; Morman, Suzette A; Plumlee, Geoffrey S; Law, Terence; Kellogg, Mark; Woolf, Alan D

2017-10-01

Though most childhood lead exposure in the USA results from ingestion of lead-based paint dust, non-paint sources are increasingly implicated. We present interdisciplinary findings from and policy implications of a case of elevated blood lead (13-18 mcg/dL, reference level <5 mcg/dL) in a 9-month-old infant, linked to a non-commercial Malaysian folk diaper powder. Analyses showed the powder contains 62 % lead by weight (primarily lead oxide) and elevated antimony [1000 parts per million (ppm)], arsenic (55 ppm), bismuth (110 ppm), and thallium (31 ppm). These metals are highly bioaccessible in simulated gastric fluids, but only slightly bioaccessible in simulated lung fluids and simulated urine, suggesting that the primary lead exposure routes were ingestion via hand-mouth transmission and ingestion of inhaled dusts cleared from the respiratory tract. Four weeks after discontinuing use of the powder, the infant's venous blood lead level was 8 mcg/dL. Unregulated, imported folk remedies can be a source of toxicant exposure. Additional research on import policy, product regulation, public health surveillance, and culturally sensitive risk communication is needed to develop efficacious risk reduction strategies in the USA. The more widespread use of contaminated folk remedies in the countries from which they originate is a substantial concern.

Noise Exposure of Teachers in Nursery Schools—Evaluation of Measures for Noise Reduction When Dropping DUPLO Toy Bricks into Storage Cases by Sound Analyses

PubMed Central

Gebauer, Konstanze; Scharf, Thomas; Baumann, Uwe; Groneberg, David A.; Bundschuh, Matthias

2016-01-01

Background: Although noise is one of the leading work-related health risk factors for teachers, many nursery schools lack sufficient noise reduction measures. Methods: This intervention study evaluated the noise exposure of nursery school teachers when dropping DUPLO toy bricks into storage cases. Sound analyses of the impact included assessment of the maximum sound pressure level (LAFmax) as well as frequency analyses with 1/3 octave band filter. For the purpose of standardization, a customized gadget was developed. Recordings were performed in 11 cases of different materials and designs to assess the impact on sound level reduction. Thereby, the acoustic effects of three damping materials (foam rubber, carpet, and PU-foam) were investigated. Results: The lowest LAFmax was measured in cases consisting of “metal grid” (90.71 dB) or of a woven willow “basket” (91.61 dB), whereas a case of “aluminium” (103.34 dB) generated the highest impact LAFmax. The frequency analyses determined especially low LAFmax in the frequency bands between 80 and 2500 Hz in cases designs “metal grid” and “basket”. The insertion of PU-foam achieved the most significant attenuation of LAFmax (−13.88 dB) and, in the frequency analyses, the best sound damping. Conclusion: The dropping of DUPLO bricks in cases contributes to the high noise level in nursery schools, but measured LAFmax show no evidence for the danger of acute hearing loss. However, continuous exposure may lead to functional impairment of the hair cells and trigger stress reactions. We recommend noise reduction by utilizing cases of woven “basket” with an insert of PU-foam. PMID:27384575

Noise Exposure of Teachers in Nursery Schools-Evaluation of Measures for Noise Reduction When Dropping DUPLO Toy Bricks into Storage Cases by Sound Analyses.

PubMed

Gebauer, Konstanze; Scharf, Thomas; Baumann, Uwe; Groneberg, David A; Bundschuh, Matthias

2016-07-04

Although noise is one of the leading work-related health risk factors for teachers, many nursery schools lack sufficient noise reduction measures. This intervention study evaluated the noise exposure of nursery school teachers when dropping DUPLO toy bricks into storage cases. Sound analyses of the impact included assessment of the maximum sound pressure level (LAFmax) as well as frequency analyses with 1/3 octave band filter. For the purpose of standardization, a customized gadget was developed. Recordings were performed in 11 cases of different materials and designs to assess the impact on sound level reduction. Thereby, the acoustic effects of three damping materials (foam rubber, carpet, and PU-foam) were investigated. The lowest LAFmax was measured in cases consisting of "metal grid" (90.71 dB) or of a woven willow "basket" (91.61 dB), whereas a case of "aluminium" (103.34 dB) generated the highest impact LAFmax. The frequency analyses determined especially low LAFmax in the frequency bands between 80 and 2500 Hz in cases designs "metal grid" and "basket". The insertion of PU-foam achieved the most significant attenuation of LAFmax (-13.88 dB) and, in the frequency analyses, the best sound damping. The dropping of DUPLO bricks in cases contributes to the high noise level in nursery schools, but measured LAFmax show no evidence for the danger of acute hearing loss. However, continuous exposure may lead to functional impairment of the hair cells and trigger stress reactions. We recommend noise reduction by utilizing cases of woven "basket" with an insert of PU-foam.

Rapid determination of lead for industrial hygiene surveys

NASA Astrophysics Data System (ADS)

Schneider, E. W.; Hill, R. F.

1982-02-01

Emphasis on the continued reduction of personnel exposure to airborne lead has led to the development and evaluation of portable instrumentation for the rapid determination of microgram quantities of lead collected on air filter samples. The instrumentation is based on radioisotope-induced X-ray fluorescence; a cadmium-109 radioisotope source is used for sample excitation, and the characteristic lead X-rays emitted are measured by a proportional detector. The effects of excitation source geometry, particle size, and interferences from other elements were investigated. This type of portable instrumentation appears ideally suited for in-plant measurements intended to monitor lead and evaluate new control measures.

Future premature mortality due to O3, secondary inorganic aerosols and primary PM in Europe--sensitivity to changes in climate, anthropogenic emissions, population and building stock.

PubMed

Geels, Camilla; Andersson, Camilla; Hänninen, Otto; Lansø, Anne Sofie; Schwarze, Per E; Skjøth, Carsten Ambelas; Brandt, Jørgen

2015-03-04

Air pollution is an important environmental factor associated with health impacts in Europe and considerable resources are used to reduce exposure to air pollution through emission reductions. These reductions will have non-linear effects on exposure due, e.g., to interactions between climate and atmospheric chemistry. By using an integrated assessment model, we quantify the effect of changes in climate, emissions and population demography on exposure and health impacts in Europe. The sensitivity to the changes is assessed by investigating the differences between the decades 2000-2009, 2050-2059 and 2080-2089. We focus on the number of premature deaths related to atmospheric ozone, Secondary Inorganic Aerosols and primary PM. For the Nordic region we furthermore include a projection on how population exposure might develop due to changes in building stock with increased energy efficiency. Reductions in emissions cause a large significant decrease in mortality, while climate effects on chemistry and emissions only affects premature mortality by a few percent. Changes in population demography lead to a larger relative increase in chronic mortality than the relative increase in population. Finally, the projected changes in building stock and infiltration rates in the Nordic indicate that this factor may be very important for assessments of population exposure in the future.

Future Premature Mortality Due to O3, Secondary Inorganic Aerosols and Primary PM in Europe — Sensitivity to Changes in Climate, Anthropogenic Emissions, Population and Building Stock

PubMed Central

Geels, Camilla; Andersson, Camilla; Hänninen, Otto; Lansø, Anne Sofie; Schwarze, Per E.; Ambelas Skjøth, Carsten; Brandt, Jørgen

2015-01-01

Air pollution is an important environmental factor associated with health impacts in Europe and considerable resources are used to reduce exposure to air pollution through emission reductions. These reductions will have non-linear effects on exposure due, e.g., to interactions between climate and atmospheric chemistry. By using an integrated assessment model, we quantify the effect of changes in climate, emissions and population demography on exposure and health impacts in Europe. The sensitivity to the changes is assessed by investigating the differences between the decades 2000–2009, 2050–2059 and 2080–2089. We focus on the number of premature deaths related to atmospheric ozone, Secondary Inorganic Aerosols and primary PM. For the Nordic region we furthermore include a projection on how population exposure might develop due to changes in building stock with increased energy efficiency. Reductions in emissions cause a large significant decrease in mortality, while climate effects on chemistry and emissions only affects premature mortality by a few percent. Changes in population demography lead to a larger relative increase in chronic mortality than the relative increase in population. Finally, the projected changes in building stock and infiltration rates in the Nordic indicate that this factor may be very important for assessments of population exposure in the future. PMID:25749320

Reduction of metal exposure of Daubenton's bats (Myotis daubentonii) following remediation of pond sediment as evidenced by metal concentrations in hair.

PubMed

Flache, Lucie; Ekschmitt, Klemens; Kierdorf, Uwe; Czarnecki, Sezin; Düring, Rolf-Alexander; Encarnação, Jorge A

2016-03-15

Transfer of contaminants from freshwater sediments via aquatic insects to terrestrial predators is well documented in spiders and birds. Here, we analyzed the metal exposure of Myotis daubentonii using an urban pond as their preferred foraging area before and after a remediation measure (sediment dredging) at this pond. Six metal elements (Zn, Cu, Cr, Cd, Pb and Ni) were measured in the sediment of the pond, in EDTA extracts of the sediment and in hair samples of M. daubentonii foraging at the pond. Samples were taken before remediation in 2011 and after remediation in 2013. Metal concentrations were quantified by ICP-OES after miniaturized microwave assisted extraction. In 2011, the pond sediment exhibited a high contamination with nickel, a moderate contamination with copper and chromium and low contents of zinc, cadmium and lead. While sediment metal contents declined only weakly after remediation, a much more pronounced reduction in the concentrations of zinc, copper, chromium and lead concentrations was observed in bat hair. Our results suggest a marked decline in metal exposure of the bats foraging at the pond as a consequence of the remediation measure. It is concluded that Daubenton's bats are suitable bioindicators of metal contamination in aquatic environments, integrating metal exposure via prey insects over their entire foraging area. We further suggest that bat hair is a useful monitoring unit, allowing a non-destructive and non-invasive assessment of metal exposure in bats. Copyright © 2015 Elsevier B.V. All rights reserved.

Microglial disruption in young mice with early chronic lead exposure☆

PubMed Central

Sobin, Christina; Montoya, Mayra Gisel Flores; Parisi, Natali; Schaub, Tanner; Cervantes, Miguel; Armijos, Rodrigo X.

2013-01-01

The mechanisms by which early chronic lead (Pb) exposure alter brain development have not been identified. We examined neuroimmune system effects in C57BL/6J mice with Pb exposure, including levels that may be common among children in lower socioeconomic income environments. Pups were exposed via dams’ drinking water from birth to post-natal day 28 to low, high or no Pb conditions. We compared gene expression of neuroinflammatory markers (study 1); and microglial mean cell body volume and mean cell body number in dentate gyrus, and dentate gyrus volume (study 2). Blood Pb levels in exposed animals at sacrifice (post-natal day 28) ranged from 2.66 to 20.31 μg/dL. Only interleukin-6 (IL6) differed between groups and reductions were dose-dependent. Microglia cell body number also differed between groups and reductions were dose-dependent. As compared with controls, microglia cell body volume was greater but highly variable in only low-dose animals; dentate gyri volumes in low- and high-dose animals were reduced. The results did not support a model of increased neuroinflammation. Instead, early chronic exposure to Pb disrupted microglia via damage to, loss of, or lack of proliferation of microglia in the developing brains of Pb-exposed animals. PMID:23598043

Lead in the environment

USGS Publications Warehouse

Pattee, Oliver H.; Pain, Deborah J.; Hoffman, David J.; Rattner, Barnett A.; Burton, G. Allen; Cairns, John

2003-01-01

Anthropogenic uses of lead have probably altered its availability and environmental distribution more than any other toxic element. Consequently, lead concentrations in many living organisms may be approaching thresholds of toxicity for the adverse effects of lead. Such thresholds are difficult to define, as they vary with the chemical and physical form of lead, exposure regime, other elements present and also vary both within and between species. The technological capability to accurately quantify low lead concentrations has increased over the last decade, and physiological and behavioral effects have been measured in wildlife with tissue lead concentrations below those previously considered safe for humans.s.236 Consequently. lead criteria for the protection of wildlife and human health are frequently under review, and 'thresholds' of lead toxicity are being reconsidered. Proposed lead criteria for the protection of natural resources have been reviewed by Eisler. Uptake of lead by plants is limited by its generally low availability in soils and sediments, and toxicity may be limited by storage mechanisms and its apparently limited translocation within most plants. Lead does not generally accumulate within the foliar parts of plants, which limits its transfer to higher trophic levels. Although lead may concentrate in plant and animal tissues, no evidence of biomagnification exists. Acid deposition onto surface waters and soils with low buffering capacity may influence the availability of lead for uptake by plants and animals, and this may merit investigation at susceptible sites. The biological significance of chronic low-level lead exposure to wildlife is sometimes difficult to quantify. Animals living in urban environments or near point sources of lead emission are inevitably subject to greater exposure to lead and enhanced risk of lead poisoning. Increasingly strict controls on lead emissions in many countries have reduced exposure to lead from some sources. and the .reduction of lead in gasoline has resulted in lower tissue lead concentrations in humans and wildlife from many, particularly urban, locations. However, it has been suggested that increasing use of organic lead compounds as catalysts for the production of plastics and as wood preservatives and biocides could adversely affect wildlife. The most significant source of direct wildlife mortality from lead is spent gunshot and fishing sinkers. Elevated mortality from shot ingestion in avian species resulted in the introduction of nontoxic (steel) shot zones along certain flyways in the United States in the mid-1970s and a total ban on the use of lead for waterfowl and coot hunting nationwide by 1992. Several other countries are now following suit and have either banned or are in the process of restricting the use of lead shot for waterfowl hunting. In the United States it has been estimated that since the 1986 hunting season. when the use of nontoxic shot became widespread. over 6 million ducks have not been lost to lead poisoning. Raptors, especially eagles, have also apparently benefited. although lead poisoning from ingestion of bullet fragments remains a problem for the critically threatened California condor. Quantifying reductions in lead mortality rates would be difficult since eagle populations throughout North America are rapidly recovering from other anthropogenic perturbations, especially organochlorine pesticides.

[Lead exposure in the ceramic tile industry: time trends and current exposure levels].

PubMed

Candela, S; Ferri, F; Olmi, M

1998-01-01

There is a high density of industries for the production of ceramic tiles in the District of Scandiano (province of Reggio Emilia, Emilia Romagna region). In this area, since the beginning of 1970s, the time trend of Pb exposure in ceramic tile plants has been evaluated by means of biological monitoring (BM) data collected at the Service of Prevention and Safety in the Work Environment and its associated Toxicology Laboratory. From these data, a clear decreasing time trend of exposure levels is documented, the reduction being more evident during the seventies and in 1985-88. During the seventies BM was introduced systematically in all ceramic tile plants with the determination of delta-aminolevulinic acid in urine (ALA-U). As a consequence of the BM programme, hygienic measures for the abatement of pollution inside the plants were implemented, and a reduction, from 20.6% to 2%, of ALA-U values exceeding 10 mg/l, was observed. In 1985, the determination of lead in blood (PbB) replaced that of ALA-U in the BM programmes and highlighted the persistence of high level of exposure to Pb, which could not be outlined by means of ALA-U because of its lower sensitivity. PbB levels were 36.1 micrograms/100 ml and 25.7 micrograms/100 ml in male and female workers, respectively. These results required the implementation, within the plants, of additional hygienic measures and a significant reduction of PbB was obtained in the following three years. In 1988 PbB levels were 26.0 +/- 10.7 and 21.6 +/- 10.3 micrograms/100 ml in male and female workers, respectively. In 1993-95 Pb levels were obtained from 1328 male and 771 female workers of 56 plants, accounting for about 40% of the total number of workers in the ceramic industry, in the zones of Sassuolo and Scandiano. Exposure levels are not different from those observed in the preceding years, with PbB levels of 25.3 +/- 11.1 and 19.1 +/- 9.2 micrograms/100 ml in male and female workers, respectively.

Exposure to Mn/Zn Ethylene-bis-Dithiocarbamate and Glyphosate Pesticides Leads to Neurodegeneration in Caenorhabditis elegans

PubMed Central

Negga, Rekek; Rudd, David A.; Davis, Nathan S.; Justice, Amanda N.; Hatfield, Holly E.; Valente, Ana L.; Fields, Anthony S.; Fitsanakis, Vanessa A.

2011-01-01

Epidemiological evidence suggests positive correlations between pesticide usage and the incidence of Parkinson's disease (PD). To further explore this relationship, we used wild type (N2) Caenorhabditis elegans (C. elegans) to test the following hypothesis: Exposure to a glyphosate-containing herbicide (TD) and/or a manganese/zinc ethylene-bis-dithiocarbamate-containing fungicide (MZ) may lead to neurotoxicity. We exposed N2 worms to varying concentrations of TD or MZ for 30 min (acute) or 24 hours (chronic). To replicate agricultural usage, a third population was exposed to TD (acute) followed by MZ (acute). For acute TD exposure, the LC50 = 8.0% (r2: = 0.6890), while the chronic LC50 = 5.7% (r2 = 0.9433). Acute MZ exposure led to an LC50 = 0.22% (r2 = 0.5093), and chronic LC50 = 0.50% (r2 = 0.9733). The combined treatment for TD + MZ yielded an LC50 = 12.5% (r2 = 0.6367). Further studies in NW1229 worms, a pan-neuronally green fluorescent protein (GFP) tagged strain, indicated a statistically significant (p < 0.05) and dose-dependent reduction in green pixel number in neurons of treated worms following each paradigm. This reduction of pixel number was accompanied by visual neurodegeneration in photomicrographs. For the dual treatment, Bliss analysis suggested synergistic interactions. Taken together, these data suggest neuronal degeneration occurs in C. elegans following treatment with environmentally-relevant concentrations of TD or MZ. PMID:21376751

Escherichia coli α-Hemolysin Triggers Shrinkage of Erythrocytes via KCa3.1 and TMEM16A Channels with Subsequent Phosphatidylserine Exposure*

PubMed Central

Skals, Marianne; Jensen, Uffe B.; Ousingsawat, Jiraporn; Kunzelmann, Karl; Leipziger, Jens; Praetorius, Helle A.

2010-01-01

α-Hemolysin from Escherichia coli (HlyA) readily lyse erythrocytes from various species. We have recently demonstrated that this pore-forming toxin provokes distinct shrinkage and crenation before it finally leads to swelling and lysis of erythrocytes. The present study documents the underlying mechanism for this severe volume reduction. We show that HlyA-induced shrinkage and crenation of human erythrocytes occur subsequent to a significant rise in [Ca2+]i. The Ca2+-activated K+ channel KCa3.1 (or Gardos channel) is essential for the initial shrinkage, because both clotrimazole and TRAM-34 prevent the shrinkage and potentiate hemolysis produced by HlyA. Notably, the recently described Ca2+-activated Cl− channel TMEM16A contributes substantially to HlyA-induced cell volume reduction. Erythrocytes isolated from TMEM16A−/− mice showed significantly attenuated crenation and increased lysis compared with controls. Additionally, we found that HlyA leads to acute exposure of phosphatidylserine in the outer leaflet of the plasma membrane. This exposure was considerably reduced by KCa3.1 antagonists. In conclusion, this study shows that HlyA triggers acute erythrocyte shrinkage, which depends on Ca2+-activated efflux of K+ via KCa3.1 and Cl− via TMEM16A, with subsequent phosphatidylserine exposure. This mechanism might potentially allow HlyA-damaged erythrocytes to be removed from the bloodstream by macrophages and thereby reduce the risk of intravascular hemolysis. PMID:20231275

Escherichia coli alpha-hemolysin triggers shrinkage of erythrocytes via K(Ca)3.1 and TMEM16A channels with subsequent phosphatidylserine exposure.

PubMed

Skals, Marianne; Jensen, Uffe B; Ousingsawat, Jiraporn; Kunzelmann, Karl; Leipziger, Jens; Praetorius, Helle A

2010-05-14

alpha-Hemolysin from Escherichia coli (HlyA) readily lyse erythrocytes from various species. We have recently demonstrated that this pore-forming toxin provokes distinct shrinkage and crenation before it finally leads to swelling and lysis of erythrocytes. The present study documents the underlying mechanism for this severe volume reduction. We show that HlyA-induced shrinkage and crenation of human erythrocytes occur subsequent to a significant rise in [Ca(2+)](i). The Ca(2+)-activated K(+) channel K(Ca)3.1 (or Gardos channel) is essential for the initial shrinkage, because both clotrimazole and TRAM-34 prevent the shrinkage and potentiate hemolysis produced by HlyA. Notably, the recently described Ca(2+)-activated Cl(-) channel TMEM16A contributes substantially to HlyA-induced cell volume reduction. Erythrocytes isolated from TMEM16A(-/-) mice showed significantly attenuated crenation and increased lysis compared with controls. Additionally, we found that HlyA leads to acute exposure of phosphatidylserine in the outer leaflet of the plasma membrane. This exposure was considerably reduced by K(Ca)3.1 antagonists. In conclusion, this study shows that HlyA triggers acute erythrocyte shrinkage, which depends on Ca(2+)-activated efflux of K(+) via K(Ca)3.1 and Cl(-) via TMEM16A, with subsequent phosphatidylserine exposure. This mechanism might potentially allow HlyA-damaged erythrocytes to be removed from the bloodstream by macrophages and thereby reduce the risk of intravascular hemolysis.

Inverse association of intellectual function with very low blood lead but not with manganese exposure in Italian adolescents

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

Lucchini, Roberto G., E-mail: lucchini@med.unibs.it; Section of Occupational Medicine, University of Brescia, P.le Spedali Civili 1, 25123 Brescia; Zoni, Silvia

Background: Pediatric lead (Pb) exposure impacts cognitive function and behavior and co-exposure to manganese (Mn) may enhance neurotoxicity. Objectives: To assess cognitive and behavioral function in adolescents with environmental exposure to Pb and Mn. Methods: In this cross sectional study, cognitive function and behavior were examined in healthy adolescents with environmental exposure to metals. The Wechsler Intelligence Scale for Children (WISC) and the Conners-Wells' Adolescent Self-Report Scale Long Form (CASS:L) were used to assess cognitive and behavioral function, respectively. ALAD polymorphisms rs1800435 and rs1139488 were measured as potential modifiers. Results: We examined 299 adolescents (49.2% females) aged 11-14 years. Bloodmore » lead (BPb) averaged 1.71 {mu}g/dL (median 1.5, range 0.44-10.2), mean Blood Manganese (BMn) was 11.1 {mu}g/dL (median 10.9, range 4.00-24.1). Average total IQ was 106.3 (verbal IQ=102, performance IQ=109.3). According to a multiple regression model considering the effect of other covariates, a reduction of about 2.4 IQ points resulted from a two-fold increase of BPb. The Benchmark Level of BPb associated with a loss of 1 IQ-point (BML01) was 0.19 {mu}g/dL, with a lower 95% confidence limit (BMLL01) of 0.11 {mu}g/dL. A very weak correlation resulted between BPb and the ADHD-like behavior (Kendall's tau rank correlation=0.074, p=0.07). No influence of ALAD genotype was observed on any outcome. Manganese was not associated with cognitive and behavioral outcomes, nor was there any interaction with lead. Conclusions: These findings demonstrate that very low level of lead exposure has a significant negative impact on cognitive function in adolescent children. Being an essential micro-nutrient, manganese may not cause cognitive effects at these low exposure levels.« less

[The umbilical blood levels of lead and some other toxic metals as a biomarker of environment-induced exposure].

PubMed

Privalova, L I; Malykh, O L; Matiukhina, G V; Gnezdilova, S V

2007-01-01

Groups of pregnant women, which made up in Revda, Pervouralsk, Krasnouralsk, and Verkh-Isetsky District of Yekaterinburg, were studied. Tests of umbilical blood samples (UB) for the levels of calcium, iron, chromium, manganese, zinc, nickel, cadmium, lead, arsenic, copper, and mercury have established that the mean concentration of lead and the proportion of samples with elevated UB lead concentrations depend on how close the residential area is located to the major industrial source of emission of this toxic metal into ambient air. This correlation is less marked for other metals or it is not found. The particular position of lead is likely to be explained by the fact that it is entirely foreign to an organism and by the comparative unimportance of a contribution of the sources of exposure to this metal, which are unassociated with man-caused environmental and food pollution. As far as other metals are concerned, the situation is complicated by the fact that they are not only toxic, but when upon minor exposures, also essential biotrace elements with controlled and interdependent toxic kinetics. It is also shown that when a pregnant woman takes a complex of biological protectors promoting a reduction in her body's levels of lead, its concentrations in her body, its UB concentration is much lower than such a bioprophylactic effect is absent.

Tobacco Smoking Status and the Contribution to Burden of Diseases in Iran, 1990-2010: findings from the Global Burden of Disease Study 2010.

PubMed

Ghasemian, Anoosheh; Rezaei, Nazila; Saeedi Moghaddam, Sahar; Mansouri, Anita; Parsaeian, Mahboubeh; Delavari, Alireza; Jamshidi, Hamid Reza; Sharifi, Farshad; Naderimagham, Shohreh

2015-08-01

Tobacco smoking and exposure to second-hand smoke in the indoor environment are major public health risks worldwide. The aim of this paper is to report and critique a global assessment of smoking prevalence, smoking-attributable deaths, and disability adjusted life years (DALYs) extracted from GBD study 2010, by sex and age in Iran from 1990 to 2010. The Global Burden of Disease (GBD) Study 2010 estimated the distributions of exposure and relative risks per unit of exposure by systematically reviewing and analyzing published and unpublished data. These assessments were used, together with estimates of death and DALYs due to specific risk factors, to calculate the attributed burden for each risk factor exposure compared with the theoretical-minimum-risk exposure. Uncertainties in the distribution of exposure, relative risks, and relevant outcomes were incorporated into estimates of attributable mortality and burden. In this study, our aim was to reformulate the GBD data, produce new graphs, and explain the results for Iran in greater detail. Between 1990 and 2010, the prevalence of tobacco smoking at all ages increased by 1% in men and declined by 2% in women in Iran, but the overall prevalence in the general population was unchanged (12%). A reduction was observed in the age-standardized death and DALY rates (per 100,000 population) attributed to tobacco smoking, including second-hand smoke. The attributed DALY rate was greater for Iranian men than for Iranian women. The highest rates of DALYs because of tobacco smoking were found in smoker men and women aged 70+, but exposure to second-hand smoke had the most significant burden in children under 5 years old. In 1990, the three leading disease burdens attributed to tobacco smoking, including second-hand smoke, were ischemic heart disease; communicable, maternal, neonatal, and nutritional disorders; and chronic respiratory diseases. In 2010, three leading burden of diseases attributed to tobacco smoking belonged to ischemic heart disease, chronic respiratory disease, and, and cerebrovascular disease, respectively. Despite a reduction in the rate of tobacco smoking, including second-hand smoke, since 1990, smoking exposure remained the fifth leading risk factor for deaths and DALYs in Iran in 2010. Overall, our data clearly show the need for new efforts in Iran to reduce the mortality and burden attributed to tobacco smoking.

The association between elevated blood lead levels and violent behavior during late adolescence: The South African Birth to Twenty Plus cohort.

PubMed

Nkomo, Palesa; Mathee, Angela; Naicker, Nisha; Galpin, Jacky; Richter, Linda M; Norris, Shane A

2017-12-01

Epidemiological studies have shown the adverse neuro-behavioral health effects of lead exposure among children, in particular. However, there is lack evidence in this regard from developing countries. The main aim of this study was to assess the association between blood lead levels (BLLs) during early adolescence and violent behavior in late adolescence. Our study sample from the Birth to Twenty Plus cohort in Soweto-Johannesburg, South Africa included 1332 study participants (684 females). BLLs were measured using blood samples collected at age 13years. Violent behavior was evaluated using data collected at ages 15 to 16years using the Youth Self Report questionnaire. First, bivariate analysis was used to examine data for an association between lead exposure in early adolescence and violent behavior items during late adolescence. Principal Component Analysis (PCA) was used for dimensionality reduction and six violent behavior components were derived. Data were further analyzed for an association between BLLs at age 13years and violent behavior using PCA derived components; to determine the specific type(s) of violent behavior associated with lead exposure. Median whole BLLs were 5.6μg/dL (p<0.001). Seventy five percent of males and 50% of females had BLLs≥5μg/dL. BLLs ranging from 5 to 9.99μg/dL were associated with physical violence (p=0.03) and BLLs≥10μg/dL were associated physical violence and fighting (p=0.02 and p=0.01, respectively). When data were analyzed using continuous BLLs physical violence was associated with lead exposure (p<0.0001). Furthermore, males were more likely to be involved in violence using a weapon (p=0.01), physical violence (p<0.0001), and robbing others (p<0.05) compared to females. The results from this study show the severe nature of violent behavior in late adolescence associated with childhood lead exposure. They highlight the urgent need for preventive measures against lead exposure among children in low or middle income countries such as South Africa. Copyright © 2017 Elsevier Ltd. All rights reserved.

Tadpole swimming performance and activity affected by acute exposure to sublethal levels of carbaryl

USGS Publications Warehouse

Bridges, C.M.

1997-01-01

General activity and swimming performance (i.e., sprint speed and distance) of plains leopard frog tadpoles (Rana blairi) were examined after acute exposure to three sublethal concentrations of carbaryl (3.5, 5.0, and 7.2 mg/L). Both swimming performance and spontaneous swimming activity are important for carrying out life history functions (e.g., growth and development) and for escaping from predators. Measured tadpole activity diminished by nearly 90% at 3.5 mg/L carbaryl and completely ceased at 7.2 mg/L. Sprint speed and sprint distance also decreased significantly following exposure. Carbaryl affected both swimming performance and activity after just 24 h, suggesting that 24 h may be an adequate length of exposure to determine behavioral effects on tadpoles. Slight recovery of activity levels was noted at 24 and 48 h post-exposure; no recovery of swimming performance was observed. Reduction in activity and swimming performance may result in increased predation rates and, because activity is closely associated with feeding, may result in slowed growth leading to a failure to emerge before pond drying or an indirect reduction in adult fitness. Acute exposure to sublethal toxicants such as carbaryl may not only affect immediate survival of tadpoles but also impact critical life history functions and generate changes at the local population level.

Exposure to environmentally persistent free radicals during gestation lowers energy expenditure and impairs skeletal muscle mitochondrial function in adult mice

PubMed Central

Stephenson, Erin J.; Ragauskas, Alyse; Jaligama, Sridhar; Redd, JeAnna R.; Parvathareddy, Jyothi; Peloquin, Matthew J.; Saravia, Jordy; Han, Joan C.; Cormier, Stephania A.

2016-01-01

We have investigated the effects of in utero exposure to environmentally persistent free radicals (EPFRs) on growth, metabolism, energy utilization, and skeletal muscle mitochondria in a mouse model of diet-induced obesity. Pregnant mice were treated with laboratory-generated, combustion-derived particular matter (MCP230). The adult offspring were placed on a high-fat diet for 12 wk, after which we observed a 9.8% increase in their body weight. The increase in body size observed in the MCP230-exposed mice was not associated with increases in food intake but was associated with a reduction in physical activity and lower energy expenditure. The reduced energy expenditure in mice indirectly exposed to MCP230 was associated with reductions in skeletal muscle mitochondrial DNA copy number, lower mRNA levels of electron transport genes, and reduced citrate synthase activity. Upregulation of key genes involved in ameliorating oxidative stress was also observed in the muscle of MCP230-exposed mice. These findings suggest that gestational exposure to MCP230 leads to a reduction in energy expenditure at least in part through alterations to mitochondrial metabolism in the skeletal muscle. PMID:27117006

Exposure to environmentally persistent free radicals during gestation lowers energy expenditure and impairs skeletal muscle mitochondrial function in adult mice.

PubMed

Stephenson, Erin J; Ragauskas, Alyse; Jaligama, Sridhar; Redd, JeAnna R; Parvathareddy, Jyothi; Peloquin, Matthew J; Saravia, Jordy; Han, Joan C; Cormier, Stephania A; Bridges, Dave

2016-06-01

We have investigated the effects of in utero exposure to environmentally persistent free radicals (EPFRs) on growth, metabolism, energy utilization, and skeletal muscle mitochondria in a mouse model of diet-induced obesity. Pregnant mice were treated with laboratory-generated, combustion-derived particular matter (MCP230). The adult offspring were placed on a high-fat diet for 12 wk, after which we observed a 9.8% increase in their body weight. The increase in body size observed in the MCP230-exposed mice was not associated with increases in food intake but was associated with a reduction in physical activity and lower energy expenditure. The reduced energy expenditure in mice indirectly exposed to MCP230 was associated with reductions in skeletal muscle mitochondrial DNA copy number, lower mRNA levels of electron transport genes, and reduced citrate synthase activity. Upregulation of key genes involved in ameliorating oxidative stress was also observed in the muscle of MCP230-exposed mice. These findings suggest that gestational exposure to MCP230 leads to a reduction in energy expenditure at least in part through alterations to mitochondrial metabolism in the skeletal muscle. Copyright © 2016 the American Physiological Society.

Lead exposure in an urban community: investigation of risk factors and assessment of the impact of lead abatement measures.

PubMed

de Freitas, Clarice Umbelino; De Capitani, Eduardo Mello; Gouveia, Nelson; Simonetti, Marcia Helena; de Paula E Silva, Mario Ramos; Kira, Carmen Silvia; Sakuma, Alice Momoyo; de Fátima Henriques Carvalho, Maria; Duran, Maria Cristina; Tiglea, Paulo; de Abreu, Maria Helena

2007-03-01

A battery recycling plant located in an urbanized area contaminated the environment with lead oxides. The Secretary of Environment of the State of São Paulo demanded an evaluation of lead exposure among the population in the vicinity of the plant. To assess the lead exposure of children, to propose control measures and evaluate the impact of these measures. Cross-sectional study of all children<13 years old in a radius of 1km from the plant responsible for the contamination. Blood lead levels (BLL) were determined for each child and questionnaires were applied to their parents. Mean BLL were compared before and after control measures were implemented. Logistic regression identified risk factors of lead exposure. Of the 850 investigated children, 311 presented BLL above the action limit established by the World Health Organization. Overall, the median BLL was 7.3 micro g/dL and it varied according to age of children (higher among 1-5 years old) and distance of the residence from the plant. Risk factors identified for BLL>10 micro g/dL were: to live in unpaved areas, parent working in the plant, distance from the plant, to play on the ground, pica, and to drink locally produced milk. After control measures were implemented (closing the plant, soil removal, dust vacuum-cleaning in the households, etc.), a reduction of 46% in BLL was observed considering the 241 re-evaluated children with levels >10 micro g/dL. This study showed that combined abatement measures were effective in reducing BLL in children living close to a contaminating source. These results informed the decision-making process regarding management of contaminated areas in Brazil.

From awareness to action: Sudbury, mining and occupational disease in a time of change

PubMed Central

Kramer, Desre M.; Holness, D. Linn; Haynes, Emily; McMillan, Keith; Berriault, Colin; Kalenge, Sheila; Lightfoot, Nancy

2017-01-01

BACKGROUND: Miners work in highly hazardous environments, but surprisingly, there are more fatalities from occupational diseases, including cancers, than from fatalities from injuries. Over the last few decades, the mining environment has become safer with fewer injuries and less exposure to the toxins that lead to occupational disease. There have been improvements in working conditions, and a reduction in the number of workers exposed, together with an overall improvement in the health of miners. OBJECTIVES: This study attempted to gain a deeper understanding of the impetus for change to reduce occupational exposures or toxins at the industry level. It focuses on one mining community in Sudbury, Ontario, with a high cancer rate, and its reduction in occupational exposures. It explored the level of awareness of occupational exposures from the perspective of industry and worker representatives in some of the deepest mines in the world. Although awareness may be necessary, it is often not a sufficient impetus for change, and it is this gap between awareness and change that this study explored. It examined the awareness of occupational disease as an impetus to reducing toxic exposures in the mining sector, and explores other forces of change at the industrial and global levels that have led to an impact on occupational exposures in mining. METHODS: From 2014 and 2016, 60 interviews were conducted with individuals who were part of, or witness to the changes in mining in Sudbury. From these, 12 labour and 10 industry interviews and four focus groups were chosen for further analysis to gain a deeper understanding of industry and labour’s views on the changes in mining and the impact on miners’ health from occupational exposures. The results from this subsection of the data is the focus for this paper. RESULTS: The themes that emerged told a story about Sudbury. There is awareness of occupational exposures, but this awareness is dwarfed in comparison to the attention that is given to the tragic fatal injuries from injuries and accidents. The mines are now owned by foreign multinationals with a change from an engaged, albeit paternalistic sense of responsibility for the health of the miners, to a less responsive or sympathetic workplace culture. Modernization has led to the elimination, substitution, or reduction of some of the worst toxins, and hence present-day miners are less exposed to hazards that lead to occupational disease than they were in the past. However, modernization and the drop in the price of nickel has also led to a precipitous reduction in the number of unionized miners, a decline in union power, a decline in the monitoring of present-day exposures, and an increase in non-unionized contract workers. The impact has been that miners have lost their solidarity and power to investigate, monitor or object to present-day exposures. CONCLUSIONS: Although an increase in the awareness of occupational hazards has made a contribution to the reduction in occupational exposures, the improvement in health of miners may be considered more as a “collateral benefit” of the changes in the mining sector. Multiple forces at the industrial and global level have differentially led to an improvement in the working and living environment. However, with the loss of union power, the miners have lost their major advocate for miner health. PMID:29036859

From awareness to action: Sudbury, mining and occupational disease in a time of change.

PubMed

Kramer, Desre M; Holness, D Linn; Haynes, Emily; McMillan, Keith; Berriault, Colin; Kalenge, Sheila; Lightfoot, Nancy

2017-01-01

Miners work in highly hazardous environments, but surprisingly, there are more fatalities from occupational diseases, including cancers, than from fatalities from injuries. Over the last few decades, the mining environment has become safer with fewer injuries and less exposure to the toxins that lead to occupational disease. There have been improvements in working conditions, and a reduction in the number of workers exposed, together with an overall improvement in the health of miners. This study attempted to gain a deeper understanding of the impetus for change to reduce occupational exposures or toxins at the industry level. It focuses on one mining community in Sudbury, Ontario, with a high cancer rate, and its reduction in occupational exposures. It explored the level of awareness of occupational exposures from the perspective of industry and worker representatives in some of the deepest mines in the world. Although awareness may be necessary, it is often not a sufficient impetus for change, and it is this gap between awareness and change that this study explored. It examined the awareness of occupational disease as an impetus to reducing toxic exposures in the mining sector, and explores other forces of change at the industrial and global levels that have led to an impact on occupational exposures in mining. From 2014 and 2016, 60 interviews were conducted with individuals who were part of, or witness to the changes in mining in Sudbury. From these, 12 labour and 10 industry interviews and four focus groups were chosen for further analysis to gain a deeper understanding of industry and labour's views on the changes in mining and the impact on miners' health from occupational exposures. The results from this subsection of the data is the focus for this paper. The themes that emerged told a story about Sudbury. There is awareness of occupational exposures, but this awareness is dwarfed in comparison to the attention that is given to the tragic fatal injuries from injuries and accidents. The mines are now owned by foreign multinationals with a change from an engaged, albeit paternalistic sense of responsibility for the health of the miners, to a less responsive or sympathetic workplace culture. Modernization has led to the elimination, substitution, or reduction of some of the worst toxins, and hence present-day miners are less exposed to hazards that lead to occupational disease than they were in the past. However, modernization and the drop in the price of nickel has also led to a precipitous reduction in the number of unionized miners, a decline in union power, a decline in the monitoring of present-day exposures, and an increase in non-unionized contract workers. The impact has been that miners have lost their solidarity and power to investigate, monitor or object to present-day exposures. Although an increase in the awareness of occupational hazards has made a contribution to the reduction in occupational exposures, the improvement in health of miners may be considered more as a "collateral benefit" of the changes in the mining sector. Multiple forces at the industrial and global level have differentially led to an improvement in the working and living environment. However, with the loss of union power, the miners have lost their major advocate for miner health.

Effects of exposure estimation errors on estimated exposure-response relations for PM2.5.

PubMed

Cox, Louis Anthony Tony

2018-07-01

Associations between fine particulate matter (PM2.5) exposure concentrations and a wide variety of undesirable outcomes, from autism and auto theft to elderly mortality, suicide, and violent crime, have been widely reported. Influential articles have argued that reducing National Ambient Air Quality Standards for PM2.5 is desirable to reduce these outcomes. Yet, other studies have found that reducing black smoke and other particulate matter by as much as 70% and dozens of micrograms per cubic meter has not detectably affected all-cause mortality rates even after decades, despite strong, statistically significant positive exposure concentration-response (C-R) associations between them. This paper examines whether this disconnect between association and causation might be explained in part by ignored estimation errors in estimated exposure concentrations. We use EPA air quality monitor data from the Los Angeles area of California to examine the shapes of estimated C-R functions for PM2.5 when the true C-R functions are assumed to be step functions with well-defined response thresholds. The estimated C-R functions mistakenly show risk as smoothly increasing with concentrations even well below the response thresholds, thus incorrectly predicting substantial risk reductions from reductions in concentrations that do not affect health risks. We conclude that ignored estimation errors obscure the shapes of true C-R functions, including possible thresholds, possibly leading to unrealistic predictions of the changes in risk caused by changing exposures. Instead of estimating improvements in public health per unit reduction (e.g., per 10 µg/m 3 decrease) in average PM2.5 concentrations, it may be essential to consider how interventions change the distributions of exposure concentrations. Copyright © 2018 Elsevier Inc. All rights reserved.

Public health assessment for petitioned Phelps Dodge Corp Douglas Reduction Works, Douglas, Cochise County, Arizona, Region 9. Cerclis No. AZD008397143. Final report

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

NONE

The Phelps-Dodge site, a former copper-smelting operation just outside Douglas and possibly Agua Prieta, Sonora, Mexico. This site contributed to lead-contaminated surface soils in residential areas in Douglas. Exposure to the lead-contaminated soils may have contributed and/or caused elevated blood levels in children living in both Douglas, AZ and Agua Prieta, Sonora, Mexico. Past emissions from the smelter included arsenic, lead, sulfur dioxide, inhalable particulate matter, and other heavy metals. The levels detected by air monitoring were elevated above health guidelines.

[Inhibition rate of gamma-aminolevulinic acid dehydratase activity in erythrocytes as a reliable index for individual workers of low lead exposure].

PubMed

Hirano, H; Omichi, M; Ohishi, H; Ishikawa, K; Hirashima, N

1983-09-01

As the delta-aminolevulinic acid dehydratase (ALAD) activity in erythrocytes is decreased by lead exposure, we considered that a net reduction of ALAD activity by lead in blood should be the difference between the activity fully activated with zinc (Zn2+) and dithiothreitol (DTT) and that without activation. The optimal condition of activation of ALAD was found by addition of 0.25 mM of Zn2+ and 10 mM of DTT in the reaction mixture. Judging from our previous results that the amount of inhibition of ALAD activity can be represented as the rate of inhibition and is closely correlated with the dose of lead administered to rabbits, the inhibition rate of ALAD activity and lead content in blood (Pb-B) of lead workers were measured. The scatter diagram obtained from the inhibition rate and lead content in blood has two groups being divided at 50 micrograms/ml of Pb-B. In one group less than 50 micrograms/100 ml of Pb-B, the inhibition rate has been closely related to Pb-B., the regression equation being Y = 1.82 X + 11.7, and the correlation coefficient + 0.926. In another group more than 50 micrograms/100 ml of Pb-B the inhibition rate remained constant at the 90% level. Measurement of the inhibition rate suggests to have practical validity for monitoring lead exposure in workers, and by means of a nomograph lead content in blood can be estimated from the inhibition rate.

Personal Exposure, Behavior, and Work Site Conditions as Determinants of Blood Lead Among Bridge Painters

PubMed Central

Rodrigues, Ema G.; Virji, M. Abbas; McClean, Michael D.; Weinberg, Janice; Woskie, Susan; Pepper, Lewis D.

2009-01-01

Bridge painters are exposed to lead during several job tasks performed during the workday, such as sanding, scraping, and blasting. After the Occupational Safety and Health Administration standard was passed in 1993 to control lead exposures among construction workers including bridge painters, this study was conducted among 84 bridge painters in the New England area to determine the significant predictors of blood lead levels. Lead was measured in personal air and hand wipe samples that were collected during the 2-week study period and in blood samples that were collected at the beginning and at the end of the study period. The personal air and hand wipe data as well as personal behaviors (i.e., smoking, washing, wearing a respirator) and work site conditions were analyzed as potential determinants of blood lead levels using linear mixed effects models. Our results show that the mean air lead levels over the 2-week period were the most predictive exposure measure of blood lead levels. Other individual-level significant predictors of blood lead levels included months worked on bridge painting crews, education, and personal hygiene index. Of the site-level variables investigated, having a containment facility on site was a significant predictor of blood lead levels. Our results also indicate that hand wipe lead levels were significantly associated with higher blood lead levels at the end of the study period compared with the beginning of the study period. Similarly, smoking on site and respirator fit testing were significantly associated with higher blood lead levels at the end of the study period. This study shows that several individual-level and site-level factors are associated with blood lead levels among bridge painters, including lead exposure through inhalation and possible hand-to-mouth contact, personal behaviors such as smoking on site, respirator fit testing, and work site conditions such as the use of better containment facilities. Accordingly, reduction in blood lead levels among bridge painters can be achieved by improving these workplace practices. PMID:19953411

Influence of a Commercial Lead Apron on Patient Skin Dose Delivered During Oral and Maxillofacial Examinations under Cone Beam Computed Tomography (CBCT).

PubMed

Schulze, Ralf Kurt Willy; Sazgar, Mahssa; Karle, Heiko; de Las Heras Gala, Hugo

2017-08-01

The purpose of this paper is to investigate the impact of a commercial lead apron on patient skin dose delivered during maxillofacial CBCT in five critical regions by means of solid-state-dosimetry. Five anatomical regions (thyroid gland, left and right breast, gonads, back of the phantom torso) in an adult female anthropomorphic phantom were selected for dose measurement by means of the highly sensitive solid-state dosimeter QUART didoSVM. Ten repeated single exposures were assessed for each patient body region for a total of five commercial CBCT devices with and without a lead apron present. Shielded and non-shielded exposures were compared under the paired Wilcoxon test, with absolute and relative differences computed. Reproducibility was expressed as the coefficient of variation (CV) between the 10 repeated assessments. The highest doses observed at skin level were found at the thyroid (mean shielded ± SD: 450.5 ± 346.7 μGy; non-shielded: 339.2 ± 348.8 μGy, p = 0.4922). Shielding resulted in a highly significant (p < 0.001) 93% dose reduction in skin dose in the female breast region with a mean non-shielded dose of approximately 35 μGy. Dose reduction was also significantly lower for the back-region (mean: -65%, p < 0.0001) as well as for the gonad-region (mean: -98%, p < 0.0001) in the shielded situation. Reproducibility was inversely correlated to skin dose (Rspearman = -0.748, p < 0.0001) with a mean CV of 10.45% (SD: 24.53 %). Skin dose in the thyroid region of the simulated patient was relatively high and not influenced by the lead apron, which did not shield this region. Dose reduction by means of a commercial lead apron was significant in all other regions, particularly in the region of the female breast.

Relative efficacy for radiation reducing methods in scoliotic patients

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

Aikenhead, J.; Triano, J.; Baker, J.

Radiation dosages to sensitive organs in full spine radiography have in recent years been a concern of physicians as well as the general public. The spine is the prime target for exposure in scoliosis radiography, though the exposure usually necessitates irradiation of several radio-sensitive organs. In recent studies, various protection techniques have been used including various lead and aluminum filtration systems, altered patient positioning and varied tube-film distances. The purpose of this study was to evaluate the efficiency for radiation dosage reduction of three filtration systems used frequently in the chiropractic profession. The systems tested were the Nolan Multiple X-raymore » Filters, the Clear-Pb system and the Sportelli Wedge system. These systems were tested in seven configurations varying breast shielding, distance and patient positioning. All systems tested demonstrated significant radiation reductions to organs, especially breast tissue. The Clear-Pb system appeared to be the most effective for all organs except the breast, and the Sportelli Wedge system demonstrated the greatest reduction to breast tissue.« less

Exposure Knowledge and Risk Perception of RF EMF

PubMed Central

Freudenstein, Frederik; Wiedemann, Peter M.; Varsier, Nadège

2015-01-01

The presented study is part of the EU-Project Low EMF Exposure Future Networks (LEXNET), which deals among other things with the issue of whether a reduction of the radiofrequency (RF) electro-magnetic fields (EMF) exposure will result in more acceptance of wireless communication networks in the public sphere. We assume that the effects of any reduction of EMF exposure will depend on the subjective link between exposure perception and risk perception (RP). Therefore we evaluated respondents’ RP of different RF EMF sources and their subjective knowledge about various exposure characteristics with regard to their impact on potential health risks. The results show that participants are more concerned about base stations than about all other RF EMF sources. Concerning the subjective exposure knowledge the results suggest that people have a quite appropriate impact model. The question how RF EMF RP is actually affected by the knowledge about the various exposure characteristics was tested in a linear regression analysis. The regression indicates that these features – except distance – do influence people’s general RF EMF RP. In addition, we analyzed the effect of the quality of exposure knowledge on RF EMF RP of various sources. The results show a tendency that better exposure knowledge leads to higher RP, especially for mobile phones. The study provides empirical support for models of the relationships between exposure perception and RP. It is not the aim to extrapolate these findings to the whole population because the samples are not exactly representative for the general public in the participating countries. PMID:25629026

Economic gains resulting from the reduction in children's exposure to lead in the United States.

PubMed Central

Grosse, Scott D; Matte, Thomas D; Schwartz, Joel; Jackson, Richard J

2002-01-01

In this study we quantify economic benefits from projected improvements in worker productivity resulting from the reduction in children's exposure to lead in the United States since 1976. We calculated the decline in blood lead levels (BLLs) from 1976 to 1999 on the basis of nationally representative National Health and Nutrition Examination Survey (NHANES) data collected during 1976 through 1980, 1991 through 1994, and 1999. The decline in mean BLL in 1- to 5-year-old U.S. children from 1976-1980 to 1991-1994 was 12.3 microg/dL, and the estimated decline from 1976 to 1999 was 15.1 microg/dL. We assumed the change in cognitive ability resulting from declines in BLLs, on the basis of published meta-analyses, to be between 0.185 and 0.323 IQ points for each 1 g/dL blood lead concentration. These calculations imply that, because of falling BLLs, U.S. preschool-aged children in the late 1990s had IQs that were, on average, 2.2-4.7 points higher than they would have been if they had the blood lead distribution observed among U.S. preschool-aged children in the late 1970s. We estimated that each IQ point raises worker productivity 1.76-2.38%. With discounted lifetime earnings of $723,300 for each 2-year-old in 2000 dollars, the estimated economic benefit for each year's cohort of 3.8 million 2-year-old children ranges from $110 billion to $319 billion. PMID:12055046

The development of an intervention programme to reduce whole-body vibration exposure at work induced by a change in behaviour: a study protocol

PubMed Central

Tiemessen, Ivo JH; Hulshof, Carel TJ; Frings-Dresen, Monique HW

2007-01-01

Background Whole body vibration (WBV) exposure at work is common and studies found evidence that this exposure might cause low back pain (LBP). A recent review concluded there is a lack of evidence of effective strategies to reduce WBV exposure. Most research in this field is focussed on the technical implications, although changing behaviour towards WBV exposure might be promising as well. Therefore, we developed an intervention programme to reduce WBV exposure in a population of drivers with the emphasis on a change in behaviour of driver and employer. The hypothesis is that an effective reduction in WBV exposure, in time, will lead to a reduction in LBP as WBV exposure is a proxy for an increased risk of LBP. Methods/Design The intervention programme was developed specifically for the drivers of vibrating vehicles and their employers. The intervention programme will be based on the most important determinants of WBV exposure as track conditions, driving speed, quality of the seat, etc. By increasing knowledge and skills towards changing these determinants, the attitude, social influence and self-efficacy (ASE) of both drivers and employers will be affected having an effect on the level of exposure. We used the well-known ASE model to develop an intervention programme aiming at a change or the intention to change behaviour towards WBV exposure. The developed programme consists of: individual health surveillance, an information brochure, an informative presentation and a report of the performed field measurements. Discussion The study protocol described is advantageous as the intervention program actively tries to change behaviour towards WBV exposure. The near future will show if this intervention program is effective by showing a decrease in WBV exposure. PMID:18005400

Environmental exposure to lead and children's intelligence at the age of seven years. The Port Pirie Cohort Study

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

Baghurst, P.A.; McMichael, A.J.; Wigg, N.R.

1992-10-29

Exposure to lead in early childhood is thought to result in delayed neuropsychological development. As yet there is little longitudinal evidence to establish whether these effects persist into later childhood. The authors measured IQ scores in 494 seven-year-old children from the lead-smelting community of Port Pirie, Australia, in whom developmental deficits associated with elevated blood lead concentrations had already been reported at the ages of two and four years. Exposure to lead was estimated from the lead concentrations in maternal blood samples drawn antenatally and at delivery and from blood samples drawn from the children at birth (umbilical-cord blood), atmore » the ages of 6 and 15 months and 2 years, and annually thereafter. Data relating to known covariates of child development were collected systematically for each child throughout the first seven years of life. The authors found inverse relations between IQ at the age of seven years and both antenatal and postnatal blood lead concentrations. After adjustment by multiple regression for sex, parents' level of education, maternal age at delivery, parents' smoking status, socioeconomic status, quality of the home environment, maternal IQ, birth weight, birth order, feeding method (breast, bottle, or both), duration of breast-feeding, and whether the child's natural parents were living together, the relation with lead exposure was still evident for postnatal blood samples, particularly within the age range of 15 months to 4 years. For an increase in blood lead concentration from 10 micrograms per deciliter (0.48 mumol per liter) to 30 micrograms per deciliter (1.45 mumol per liter), expressed as the average of the concentrations at 15 months and 2, 3, and 4 years, the estimated reduction in the IQ of the children was in the range of 4.4 points (95 percent confidence interval, 2.2 to 6.6) to 5.3 points (95 percent confidence interval, 2.8 to 7.8).« less

Metal exposures from aluminum cookware: An unrecognized public health risk in developing countries.

PubMed

Weidenhamer, Jeffrey D; Fitzpatrick, Meghann P; Biro, Alison M; Kobunski, Peter A; Hudson, Michael R; Corbin, Rebecca W; Gottesfeld, Perry

2017-02-01

Removing lead from gasoline has resulted in decreases in blood lead levels in most of the world, but blood lead levels remain elevated in low and middle-income countries compared to more developed countries. Several reasons for this difference have been investigated, but few studies have examined the potential contribution from locally-made aluminum cookware. In a previous study of cookware from a single African country, Cameroon, artisanal aluminum cookware that is made from scrap metal released significant quantities of lead. In this study, 42 intact aluminum cookware items from ten developing countries were tested for their potential to release lead and other metals during cooking. Fifteen items released ≥1 microgram of lead per serving (250mL) when tested by boiling with dilute acetic acid for 2h. One pot, from Viet Nam, released 33, 1126 and 1426 micrograms per serving in successive tests. Ten samples released >1 microgram of cadmium per serving, and fifteen items released >1 microgram of arsenic per serving. The mean exposure estimate for aluminum was 125mg per serving, more than six times the World Health Organization's Provisional Tolerable Weekly Intake of 20mg/day for a 70kg adult, and 40 of 42 items tested exceeded this level. We conducted preliminary assessments of three potential methods to reduce metal leaching from this cookware. Coating the cookware reduced aluminum exposure per serving by >98%, and similar reductions were seen for other metals as well. Potential exposure to metals by corrosion during cooking may pose a significant and largely unrecognized public health risk which deserves urgent attention. Copyright © 2016 Elsevier B.V. All rights reserved.

Lead (Pb) and other metals in New York City community garden soils: factors influencing contaminant distributions

PubMed Central

Mitchell, Rebecca G.; Spliethoff, Henry M.; Ribaudo, Lisa N.; Lopp, Donna M.; Shayler, Hannah A.; Marquez-Bravo, Lydia G.; Lambert, Veronique T.; Ferenz, Gretchen S.; Russell-Anelli, Jonathan M.; Stone, Edie B.; McBride, Murray B.

2014-01-01

Urban gardens provide affordable fresh produce to communities with limited access to healthy food but may also increase exposure to lead (Pb) and other soil contaminants. Metals analysis of 564 soil samples from 54 New York City (NYC) community gardens found at least one sample exceeding health-based guidance values in 70% of gardens. However, most samples (78%) did not exceed guidance values, and medians were generally below those reported in NYC soil and other urban gardening studies. Barium (Ba) and Pb most frequently exceeded guidance values and along with cadmium (Cd) were strongly correlated with zinc (Zn), a commonly measured nutrient. Principal component analysis suggested that contaminants varied independently from organic matter and geogenic metals. Contaminants were associated with visible debris and a lack of raised beds; management practices (e.g., importing uncontaminated soil) have likely reduced metals concentrations. Continued exposure reduction efforts would benefit communities already burdened by environmental exposures. PMID:24502997

Lead (Pb) and other metals in New York City community garden soils: factors influencing contaminant distributions.

PubMed

Mitchell, Rebecca G; Spliethoff, Henry M; Ribaudo, Lisa N; Lopp, Donna M; Shayler, Hannah A; Marquez-Bravo, Lydia G; Lambert, Veronique T; Ferenz, Gretchen S; Russell-Anelli, Jonathan M; Stone, Edie B; McBride, Murray B

2014-04-01

Urban gardens provide affordable fresh produce to communities with limited access to healthy food but may also increase exposure to lead (Pb) and other soil contaminants. Metals analysis of 564 soil samples from 54 New York City (NYC) community gardens found at least one sample exceeding health-based guidance values in 70% of gardens. However, most samples (78%) did not exceed guidance values, and medians were generally below those reported in NYC soil and other urban gardening studies. Barium (Ba) and Pb most frequently exceeded guidance values and along with cadmium (Cd) were strongly correlated with zinc (Zn), a commonly measured nutrient. Principal component analysis suggested that contaminants varied independently from organic matter and geogenic metals. Contaminants were associated with visible debris and a lack of raised beds; management practices (e.g., importing uncontaminated soil) have likely reduced metals concentrations. Continued exposure reduction efforts would benefit communities already burdened by environmental exposures. Copyright © 2014 Elsevier Ltd. All rights reserved.

Lead and cadmium in public health in Nigeria: physicians neglect and pitfall in patient management.

PubMed

Orisakwe, Orish Ebere

2014-02-01

Low-level heavy metals exposure may contribute much more toward the causation of chronic disease and impaired functioning than previously thought. Among the suggested preventive and intervention measures for the control of renal diseases are the reduction in the exposure to heavy metals. Although these indicate knowledge and awareness of possible role of some heavy metals in the etiogenesis of some chronic diseases by Nigerian Physicians, heavy metal assay as diagnostic guide in patient management is often omitted in most healthcare settings. This is a synoptic capture of the increased incidence and prevalence of some metabolic disorders where heavy metals may be implicated. A search of the terms heavy metal exposure, source, toxicity, metabolic disorders, poisoning in Nigeria, in bibliographical databases (in English language) such as PubMed, Scopus, Google Scholar, and Africa Journal Online (AJOL) digital library was conducted. Leaded gasoline, refuse dumping, absence of poison information centers, and poor record keeping characterize environmental health in Nigeria. Lead and cadmium are of most significant public health importance in Nigeria. The recognition and inclusion of heavy metals assays in the diagnosis of metabolic disorders may ensure early diagnosis and improve management.

Lead and Cadmium in Public Health in Nigeria: Physicians Neglect and Pitfall in Patient Management

PubMed Central

Orisakwe, Orish Ebere

2014-01-01

Low-level heavy metals exposure may contribute much more toward the causation of chronic disease and impaired functioning than previously thought. Among the suggested preventive and intervention measures for the control of renal diseases are the reduction in the exposure to heavy metals. Although these indicate knowledge and awareness of possible role of some heavy metals in the etiogenesis of some chronic diseases by Nigerian Physicians, heavy metal assay as diagnostic guide in patient management is often omitted in most healthcare settings. This is a synoptic capture of the increased incidence and prevalence of some metabolic disorders where heavy metals may be implicated. A search of the terms heavy metal exposure, source, toxicity, metabolic disorders, poisoning in Nigeria, in bibliographical databases (in English language) such as PubMed, Scopus, Google Scholar, and Africa Journal Online (AJOL) digital library was conducted. Leaded gasoline, refuse dumping, absence of poison information centers, and poor record keeping characterize environmental health in Nigeria. Lead and cadmium are of most significant public health importance in Nigeria. The recognition and inclusion of heavy metals assays in the diagnosis of metabolic disorders may ensure early diagnosis and improve management. PMID:24696827

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.

[Blood lead levels in children from a ceramic center with respect to residence and parental occupation].

PubMed

Ferri, F; Candela, S; Bedeschi, E; Picciati, A M; Davoli, V; Rinaldi, L; Riccò, D

1998-01-01

In a survey carried out in 1981, Pb exposure of children living in two geographical areas of the district of Scandiano and attending the first year of primary school was studied. The two areas were different concerning both traffic and the presence of ceramic tile industries, thus suggesting a different exposure of children. The survey demonstrated blood lead levels (PbB) markedly higher than 10 micrograms/100 ml, a value recently identified by the Centers for Disease Control (CDC, Atlanta, USA) as the limit beyond which children's learning capacity may be damaged. It was evident that both the occupational exposure of parents and, to a lower extent, the residence in zones with higher levels of pollution influenced PbB levels. During the last ten years significant improvements have led to the reduction of atmospheric emissions and of occupational exposure of ceramic workers. A new survey has been carried out in 1995. We examined 147 children attending the first year of primary school, and living in two zones for which a different level of Pb exposure could be assumed. In both zones, a clear reduction of PbB was observed in comparison with data obtained in 1981. Mean and standard deviation for PbB in the two groups were 4.1 +/- 1.71 and 4.5 +/- 2.04 micrograms/100 ml, with median values of 3.7 and 4.0 micrograms/100 ml, respectively. Only two cases (1.4%) exceeded the limit values proposed by CDC. Although the mean PbB were much lower than those observed in 1981, higher PbB were found in children whose parents were occupationally exposed to Pb. Maternal exposure seems to be particularly important in determining PbB in children. In comparison with data from the international literature, our results are very close to those obtained for children living in Scandinavian countries, in Germany or in France and rather different from those obtained by other authors in Italy.

Water body and riparian buffer strip characteristics in a vineyard area to support aquatic pesticide exposure assessment.

PubMed

Ohliger, Renja; Schulz, Ralf

2010-10-15

The implementation of a geodata-based probabilistic pesticide exposure assessment for surface waters in Germany offers the opportunity to base the exposure estimation on more differentiated assumptions including detailed landscape characteristics. Since these characteristics can only be estimated using field surveys, water body width and depth, hydrology, riparian buffer strip width, ground vegetation cover, existence of concentrated flow paths, and riparian vegetation were characterised at 104 water body segments in the vineyard region Palatinate (south-west Germany). Water body segments classified as permanent (n=43) had median values of water body width and depth of 0.9m and 0.06m, respectively, and the determined median width:depth ratio was 15. Thus, the deterministic water body model (width=1m; depth=0.3m) assumed in regulatory exposure assessment seems unsuitable for small water bodies in the study area. Only 25% of investigated buffer strips had a dense vegetation cover (>70%) and allow a laminar sheet flow as required to include them as an effective pesticide runoff reduction landscape characteristic. At 77 buffer strips, bordering field paths and erosion rills leading into the water body were present, concentrating pesticide runoff and consequently decreasing buffer strip efficiency. The vegetation type shrubbery (height>1.5m) was present at 57 (29%) investigated riparian buffer strips. According to their median optical vegetation density of 75%, shrubberies may provide a spray drift reduction of 72±29%. Implementing detailed knowledge in an overall assessment revealed that exposure via drift might be 2.4 and via runoff up to 1.6 fold higher than assumed by the deterministic approach. Furthermore, considering vegetated buffer strips only by their width leads to an underestimation of exposure by a factor of as much as four. Our data highlight that the deterministic model assumptions neither represent worst-case nor median values and therefore cannot simply be adopted in a probabilistic approach. Copyright © 2010 Elsevier B.V. All rights reserved.

Early generation selection for rice fissure resistance proves effective and indicates a fissure resistance gene on chromsome 1

USDA-ARS?s Scientific Manuscript database

Whole rice kernels have two to three times more market value than brokens, which means that any reduction in milling yield results in financial losses for both rice producers and millers. One of the leading causes of reduced milling yield is exposure of the rice kernels to severe moisture changes b...

Effects of combined exposure to formaldehyde and benzene on immune cells in the blood and spleen in Balb/c mice.

PubMed

Wen, Huaxiao; Yuan, Langyue; Wei, Chenxi; Zhao, Yun; Qian, Yan; Ma, Ping; Ding, Shumao; Yang, Xu; Wang, Xianliang

2016-07-01

Formaldehyde and benzene are the two major indoor air pollutants due to their prevalence and toxicity. This study aimed to explore the toxic effect on the spleen and relevant immune responses of Balb/c mice caused by exposure to a combination of formaldehyde and benzene. Balb/c mice were divided randomly into five groups (n=9/group): blank control group (Ctrl); solvent ([corn] Oil) control; formaldehyde only (FA, 3mg/m(3)); benzene only (BZ, 150mg/kg BW); and, formaldehyde+benzene group (FA+BZ). Exposures were performed for 8h/day, 5 day/week, for 2 weeks. Tail blood was collected after the final exposure; 24-h later, the mice were euthanized to permit assessment of a variety of immune endpoints. The endpoints' three areas were: (1) in living mice, body weight and delayed-type hypersensitivity (DTH) responses; (2) in blood, immune cell counts and serum antibody levels (serum hemagglutination); and, (3) in spleen samples, reactive oxygen species (ROS), malondialdehyde (MDA), glutathione (GSH), caspase-3 (cell apoptosis) levels and lymphocyte proliferation. In this study we fund (1) BZ and FA+BZ exposure can lead to the reduction in the number of some immune cells in peripheral blood; (2) Formaldehyde has certain synergistic effects on benzene-induced cytotoxicity in peripheral blood, (3) FA, BZ and FA+BZ exposure can lead to ROS and GSH depletion in spleen cells, and spleen cell apoptosis (caspase-3 increased) may be one of the downstream events, decreased splenic lymphocyte proliferation; and (4) the FA+BZ combined exposure can lead to the decreased body weight, serum antibody level (by serum hemagglutination assay). Copyright © 2016 Elsevier B.V. All rights reserved.

Determining a threshold sub-acute dose leading to minimal physiological alterations following prolonged exposure to the nerve agent VX in rats.

PubMed

Bloch-Shilderman, E; Rabinovitz, I; Egoz, I; Yacov, G; Allon, N; Nili, U

2018-02-01

VX, a potent inhibitor of cholinesterase (ChE), is considered as one of the most toxic, persistent and least volatile nerve agents. VX is absorbed in various environmental surfaces and is gradually released long after its initial dispersal. Its toxicity is mainly caused by disrupting central and peripheral cholinergic nervous system activity, leading to potential long-term detrimental effects on health. The primary objective of the present study was to assess the threshold VX dose leading to minimal physiological alterations following prolonged VX exposure. Characterization of such a threshold is crucial for dealing with unresolved operative dilemmas such as when it is safe enough to resettle a population that has been evacuated from a VX-contaminated area. Rats, continuously exposed to various doses of VX (0.225-45 µg/kg/day) for 4 weeks via implanted mini-osmotic pumps, showed a dose-dependent and continuous decrease in ChE activity in whole blood, brain and muscles, ranging between 20 and 100%. Exposure to 13.5 µg/kg/day led to a stable low ChE activity level (~ 20%), accompanied by transient and negligible electrocorticogram spectral power transformations, especially in the theta and alpha brain wave frequencies, and a significant decrease in total brain M2 receptor density. These changes were neither accompanied by observable signs of intoxication nor by changes in motor function, circadian rhythm or TSPO level (a reliable marker of brain damage). Following exposure to lower doses of 2.25 and 0.225 µg/kg/day, the only change measured was a reduction in ChE activity of 60 and 20%, respectively. Based on these results, we delineate ChE inhibition as the physiological measure most susceptible to alterations following prolonged VX exposure, and determine for the first time the threshold sub-acute VX dose for minimal physiological effects (up to 20% reduction in ChE activity) in the rat as 0.225 µg/kg/day.

The Importance of Moisture in Hybrid Lead Halide Perovskite Thin Film Fabrication.

PubMed

Eperon, Giles E; Habisreutinger, Severin N; Leijtens, Tomas; Bruijnaers, Bardo J; van Franeker, Jacobus J; deQuilettes, Dane W; Pathak, Sandeep; Sutton, Rebecca J; Grancini, Giulia; Ginger, David S; Janssen, Rene A J; Petrozza, Annamaria; Snaith, Henry J

2015-09-22

Moisture, in the form of ambient humidity, has a significant impact on methylammonium lead halide perovskite films. In particular, due to the hygroscopic nature of the methylammonium component, moisture plays a significant role during film formation. This issue has so far not been well understood and neither has the impact of moisture on the physical properties of resultant films. Herein, we carry out a comprehensive and well-controlled study of the effect of moisture exposure on methylammonium lead halide perovskite film formation and properties. We find that films formed in higher humidity atmospheres have a less continuous morphology but significantly improved photoluminescence, and that film formation is faster. In photovoltaic devices, we find that exposure to moisture, either in the precursor solution or in the atmosphere during formation, results in significantly improved open-circuit voltages and hence overall device performance. We then find that by post-treating dry films with moisture exposure, we can enhance photovoltaic performance and photoluminescence in a similar way. The enhanced photoluminescence and open-circuit voltage imply that the material quality is improved in films that have been exposed to moisture. We determine that this improvement stems from a reduction in trap density in the films, which we postulate to be due to the partial solvation of the methylammonium component and "self-healing" of the perovskite lattice. This work highlights the importance of controlled moisture exposure when fabricating high-performance perovskite devices and provides guidelines for the optimum environment for fabrication. Moreover, we note that often an unintentional water exposure is likely responsible for the high performance of solar cells produced in some laboratories, whereas careful synthesis and fabrication in a dry environment will lead to lower-performing devices.

Second hand tobacco smoke adversely affects the bone of immature rats.

PubMed

Rosa, Rodrigo César; Pereira, Sângela Cunha; Cardoso, Fabrizio Antônio Gomide; Caetano, Abadio Gonçalves; Santiago, Hildemberg Agostinho Rocha de; Volpon, José Batista

2017-12-01

To evaluate the influence of secondhand cigarette smoke exposure on longitudinal growth of the tibia of growing rats and some parameters of bone quality. Forty female rats were randomly divided into four groups: control: rats were sham exposed; 30 days: rats were exposed to tobacco smoke for 30 days; 45 days: rats were exposed to tobacco smoke for 45 days; and 60 days: rats were exposed to tobacco smoke for 60 days. Blood samples were collected to evaluate the levels of cotinine and alkaline phosphatase. Both tibias were dissected and weighed; the lengths were measured, and the bones were then stored in a freezer for analysis of bone mineral content and mechanical resistance (maximal load and stiffness). Exposure of rats to tobacco smoke significantly compromised bone health, suggesting that the harmful effects may be time dependent. Harmful effects on bone growth were detected and were more pronounced at 60-day follow-ups with a 41.8% reduction in alkaline phosphatase levels (p<0.01) and a decrease of 11.25% in tibia length (p<0.001). Furthermore, a 41.5% decrease in bone mineral density was observed (p<0.001), leading to a 42.8% reduction in maximum strength (p<0.001) and a 56.7% reduction in stiffness (p<0.001). Second hand cigarette smoke exposure in rats affected bones that were weaker, deforming them and making them osteopenic. Additionally, the long bone was shorter, suggesting interference with growth. Such events seem to be related to time of exposure.

Can environmental or occupational hazards alter the sex ratio at birth? A systematic review

PubMed Central

Terrell, Metrecia L.; Hartnett, Kathleen P.; Marcus, Michele

2011-01-01

More than 100 studies have examined whether environmental or occupational exposures of parents affect the sex ratio of their offspring at birth. For this review, we searched Medline and Web of Science using the terms ‘sex ratio at birth’ and ‘sex ratio and exposure’ for all dates, and reviewed bibliographies of relevant studies to find additional articles. This review focuses on exposures that have been the subject of at least four studies including polychlorinated biphenyls (PCBs), dioxins, pesticides, lead and other metals, radiation, boron, and g-forces. For paternal exposures, only dioxins and PCBs were consistently associated with sex ratios higher or lower than the expected 1.06. Dioxins were associated with a decreased proportion of male births, whereas PCBs were associated with an increased proportion of male births. There was limited evidence for a decrease in the proportion of male births after paternal exposure to DBCP, lead, methylmercury, non-ionizing radiation, ionizing radiation treatment for childhood cancer, boron, or g-forces. Few studies have found higher or lower sex ratios associated with maternal exposures. Studies in humans and animals have found a reduction in the number of male births associated with lower male fertility, but the mechanism by which environmental hazards might change the sex ratio has not yet been established. PMID:24149027

Chinese Pediatrician Attitudes and Practices Regarding Child Exposure to Secondhand Smoke (SHS) and Clinical Efforts against SHS Exposure

PubMed Central

Huang, Kaiyong; Abdullah, Abu S.; Huo, Haiying; Liao, Jing; Yang, Li; Zhang, Zhiyong; Chen, Hailian; Nong, Guangmin; Winickoff, Jonathan P.

2015-01-01

Background: Secondhand Smoke (SHS) exposure is a leading cause of childhood illness and premature death. Pediatricians play an important role in helping parents to quit smoking and reducing children’s SHS exposure. This study examined Chinese pediatricians’ attitudes and practices regarding children’s exposure to SHS and clinical efforts against SHS exposure. Methods: A cross-sectional survey of pediatricians was conducted in thirteen conveniently selected hospitals in southern China, during September to December 2013. Five hundred and four pediatricians completed self-administered questionnaires with a response rate of 92%. χ2 tests were used to compare categorical variables differences between smokers and non-smokers and other categorical variables. Results: Pediatricians thought that the key barriers to encouraging parents to quit smoking were: lack of professional training (94%), lack of time (84%), resistance to discussions about smoking (77%). 94% of the pediatricians agreed that smoking in enclosed public places should be prohibited and more than 70% agreed that smoking should not be allowed in any indoor places and in cars. Most of the pediatricians thought that their current knowledge on helping people to quit smoking and SHS exposure reduction counseling was insufficient. Conclusions: Many Chinese pediatricians did not have adequate knowledge about smoking and SHS, and many lacked confidence about giving cessation or SHS exposure reduction counseling to smoking parents. Lack of professional training and time were the most important barriers to help parents quit smoking among the Chinese pediatricians. Intensified efforts are called for to provide the necessary professional training and increase pediatricians’ participation in the training. PMID:26006117

Mental Health Nurse's Exposure to Workplace Violence Leads to Job Stress, Which Leads to Reduced Professional Quality of Life.

PubMed

Itzhaki, Michal; Bluvstein, Irit; Peles Bortz, Anat; Kostistky, Hava; Bar Noy, Dor; Filshtinsky, Vivian; Theilla, Miriam

2018-01-01

Professional quality of life (ProQOL) reflects how individuals feel about their work as helpers. Psychiatric ward nurses cope with significant psychological and physical challenges, including exposure to verbal and physical violence. This study was based on two aspects of ProQOL, the positive compassion satisfaction, and the negative compassion fatigue, with the aim of investigating the relation of ProQOL to job stress and violence exposure at a large mental health center. Data were collected from 114 mental health nurses (49/63 M/F) who completed a self-administered questionnaire examining violence exposure, ProQOL, and job stress. The results showed that during the last year, almost all nurses (88.6%) experienced verbal violence, and more than half (56.1%) experienced physical violence. Only 2.6% experienced no violence. ProQOL was not associated with violence exposure but was reduced by work stress and by previous exposure to violence; nurses who perceived their work as more stressful had lower satisfaction from their work. In conclusion, although most mental health nurses are exposed to physical and verbal violence, their ProQOL is more related to job stress than to workplace violence (WPV). Hospital managements should conduct work stress reduction intervention programs and promote strategizes to reduce WPV. Further exploration of (a) factors affecting ProQOL and (b) the effect of violence coping workshops on ProQOL is warranted.

Cigarette Smoke Exposure during Pregnancy Alters Fetomaternal Cell Trafficking Leading to Retention of Microchimeric Cells in the Maternal Lung

PubMed Central

Vogelgesang, Anja; Scapin, Cristina; Barone, Caroline; Tam, Elaine

2014-01-01

Cigarette smoke exposure causes chronic oxidative lung damage. During pregnancy, fetal microchimeric cells traffic to the mother. Their numbers are increased at the site of acute injury. We hypothesized that milder chronic diffuse smoke injury would attract fetal cells to maternal lungs. We used a green-fluorescent-protein (GFP) mouse model to study the effects of cigarette smoke exposure on fetomaternal cell trafficking. Wild-type female mice were exposed to cigarette smoke for about 4 weeks and bred with homozygote GFP males. Cigarette smoke exposure continued until lungs were harvested and analyzed. Exposure to cigarette smoke led to macrophage accumulation in the maternal lung and significantly lower fetal weights. Cigarette smoke exposure influenced fetomaternal cell trafficking. It was associated with retention of GFP-positive fetal cells in the maternal lung and a significant reduction of fetal cells in maternal livers at gestational day 18, when fetomaternal cell trafficking peaks in the mouse model. Cells quickly clear postpartum, leaving only a few, difficult to detect, persisting microchimeric cells behind. In our study, we confirmed the postpartum clearance of cells in the maternal lungs, with no significant difference in both groups. We conclude that in the mouse model, cigarette smoke exposure during pregnancy leads to a retention of fetal microchimeric cells in the maternal lung, the site of injury. Further studies will be needed to elucidate the effect of cigarette smoke exposure on the phenotypic characteristics and function of these fetal microchimeric cells, and confirm its course in cigarette smoke exposure in humans. PMID:24832066

Household air pollution following replacement of traditional open fire with an improved rocket type cookstove.

PubMed

Ochieng, Caroline; Vardoulakis, Sotiris; Tonne, Cathryn

2017-02-15

Cooking with biomass fuel is an important source of household air pollution (HAP) in developing countries, and a leading risk factor for ill-health. Although various designs of "improved cookstoves" (ICS) have been promoted as HAP interventions in these settings, few of them have undergone in-field evaluation, partly due to the challenge of conducting field measurements in remote settings. In this study we assessed the change in carbon monoxide (CO) exposure following the replacement of the traditional three-stone stove with a popular ICS in 49 homes in Western Kenya. We also assessed the suitability of using kitchen CO as a proxy for kitchen PM 2.5 . Reduction in 48h mean kitchen CO was 3.1ppm (95% CI: -8.1, 1.8) and in personal CO was 0.9ppm (95% CI: -4.3, 2.6) following stove replacements. Overall, 48-h kitchen and personal CO exposures were lower after stove replacement (28% and 12%, respectively) but with wide confidence intervals that also suggested possible increases in exposure. There were statistically significant reductions in peak kitchen and personal CO concentrations represented by the 8-h 95th percentile: reductions of 26.1ppm (95% CI: -44.6, -7.6) and 8.0ppm (95% CI: -12.2, -3.8), respectively. This is equivalent to 53% reduction in kitchen CO and 39% reduction in personal CO. We found good correlation between kitchen CO and PM 2.5 concentrations overall (r=0.73, n=33 over averaging periods approximating 1day), which varied by time of day and exposure setting. These variations limit the applicability of CO as a proxy measure for PM 2.5 concentrations. A combination of interventions, including better designed stoves, improved ventilation and cleaner fuels, may be needed to reduce HAP to levels that are likely to improve health. Copyright © 2016. Published by Elsevier B.V.

Maternal choline supplementation in a sheep model of first trimester binge alcohol fails to protect against brain volume reductions in peripubertal lambs

PubMed Central

Birch, Sharla M.; Lenox, Mark W.; Kornegay, Joe N.; Paniagua, Beatriz; Styner, Martin A.; Goodlett, Charles R.; Cudd, Tim A.; Washburn, Shannon E.

2016-01-01

Fetal alcohol spectrum disorder (FASD) is a leading potentially preventable birth defect. Poor nutrition may contribute to adverse developmental outcomes of prenatal alcohol exposure, and supplementation of essential micronutrients such as choline has shown benefit in rodent models. The sheep model of first-trimester binge alcohol exposure was used in this study to model the dose of maternal choline supplementation used in an ongoing prospective clinical trial involving pregnancies at risk for FASD. Primary outcome measures included volumetrics of the whole brain, cerebellum, and pituitary derived from magnetic resonance imaging (MRI) in 6-month-old lambs, testing the hypothesis that alcohol-exposed lambs would have brain volume reductions that would be ameliorated by maternal choline supplementation. Pregnant sheep were randomly assigned to one of five groups – heavy binge alcohol (HBA; 2.5 g/kg/treatment ethanol), heavy binge alcohol plus choline supplementation (HBC; 2.5 g/kg/treatment ethanol and 10 mg/kg/day choline), saline control (SC), saline control plus choline supplementation (SCC; 10 mg/kg/day choline), and normal control (NC). Ewes were given intravenous alcohol (HBA, HBC; mean peak BACs of ~280 mg/dL) or saline (SC, SCC) on three consecutive days per week from gestation day (GD) 4–41; choline was administered on GD 4–148. MRI scans of lamb brains were performed postnatally on day 182. Lambs from both alcohol groups (with or without choline) showed significant reductions in total brain volume; cerebellar and pituitary volumes were not significantly affected. This is the first report of MRI-derived volumetric brain reductions in a sheep model of FASD following binge-like alcohol exposure during the first trimester. These results also indicate that maternal choline supplementation comparable to doses in human studies fails to prevent brain volume reductions typically induced by first-trimester binge alcohol exposure. Future analyses will assess behavioral outcomes along with regional brain and neurohistological measures. PMID:27788773

Adolescent, but Not Adult, Binge Ethanol Exposure Leads to Persistent Global Reductions of Choline Acetyltransferase Expressing Neurons in Brain

PubMed Central

Vetreno, Ryan P.; Broadwater, Margaret; Liu, Wen; Spear, Linda P.; Crews, Fulton T.

2014-01-01

During the adolescent transition from childhood to adulthood, notable maturational changes occur in brain neurotransmitter systems. The cholinergic system is composed of several distinct nuclei that exert neuromodulatory control over cognition, arousal, and reward. Binge drinking and alcohol abuse are common during this stage, which might alter the developmental trajectory of this system leading to long-term changes in adult neurobiology. In Experiment 1, adolescent intermittent ethanol (AIE; 5.0 g/kg, i.g., 2-day on/2-day off from postnatal day [P] 25 to P55) treatment led to persistent, global reductions of choline acetyltransferase (ChAT) expression. Administration of the Toll-like receptor 4 agonist lipopolysaccharide to young adult rats (P70) produced a reduction in ChAT+IR that mimicked AIE. To determine if the binge ethanol-induced ChAT decline was unique to the adolescent, Experiment 2 examined ChAT+IR in the basal forebrain following adolescent (P28–P48) and adult (P70–P90) binge ethanol exposure. Twenty-five days later, ChAT expression was reduced in adolescent, but not adult, binge ethanol-exposed animals. In Experiment 3, expression of ChAT and vesicular acetylcholine transporter expression was found to be significantly reduced in the alcoholic basal forebrain relative to moderate drinking controls. Together, these data suggest that adolescent binge ethanol decreases adult ChAT expression, possibly through neuroimmune mechanisms, which might impact adult cognition, arousal, or reward sensitivity. PMID:25405505

Adolescent, but not adult, binge ethanol exposure leads to persistent global reductions of choline acetyltransferase expressing neurons in brain.

PubMed

Vetreno, Ryan P; Broadwater, Margaret; Liu, Wen; Spear, Linda P; Crews, Fulton T

2014-01-01

During the adolescent transition from childhood to adulthood, notable maturational changes occur in brain neurotransmitter systems. The cholinergic system is composed of several distinct nuclei that exert neuromodulatory control over cognition, arousal, and reward. Binge drinking and alcohol abuse are common during this stage, which might alter the developmental trajectory of this system leading to long-term changes in adult neurobiology. In Experiment 1, adolescent intermittent ethanol (AIE; 5.0 g/kg, i.g., 2-day on/2-day off from postnatal day [P] 25 to P55) treatment led to persistent, global reductions of choline acetyltransferase (ChAT) expression. Administration of the Toll-like receptor 4 agonist lipopolysaccharide to young adult rats (P70) produced a reduction in ChAT+IR that mimicked AIE. To determine if the binge ethanol-induced ChAT decline was unique to the adolescent, Experiment 2 examined ChAT+IR in the basal forebrain following adolescent (P28-P48) and adult (P70-P90) binge ethanol exposure. Twenty-five days later, ChAT expression was reduced in adolescent, but not adult, binge ethanol-exposed animals. In Experiment 3, expression of ChAT and vesicular acetylcholine transporter expression was found to be significantly reduced in the alcoholic basal forebrain relative to moderate drinking controls. Together, these data suggest that adolescent binge ethanol decreases adult ChAT expression, possibly through neuroimmune mechanisms, which might impact adult cognition, arousal, or reward sensitivity.

Prenatal chemical exposures and child language development.

PubMed

Dzwilewski, Kelsey L C; Schantz, Susan L

2015-01-01

The goal of this review is to summarize the evidence that prenatal and/or early postnatal exposure to certain chemicals, both manmade (insulating materials, flame retardants, pesticides) and naturally occurring (e.g., lead, mercury), may be associated with delays or impairments in language development. We focus primarily on a subset of more extensively studied chemicals-polychlorinated biphenyls (PCBs), lead, and methyl mercury-for which a reasonable body of literature on neurodevelopmental outcomes is available. We also briefly summarize the smaller body of evidence for other chemicals including polybrominated diphenyl ether flame retardants (PBDEs) and organophosphate pesticides. Very few studies have used specific assessments of language development and function. Therefore, we included discussion of aspects of cognitive development such as overall intellectual functioning and verbal abilities that rely on language, as well as aspects of cognition such as verbal and auditory working memory that are critical underpinnings of language development. A high percentage of prospective birth cohort studies of PCBs, lead, and mercury have reported exposure-related reductions in overall IQ and/or verbal IQ that persist into middle or late childhood. Given these findings, it is important that clinicians and researchers in communication sciences and disorders are aware of the potential for environmental chemicals to impact language development. The goal of this review is to summarize the evidence that prenatal and/or early postnatal exposure to certain chemicals may be associated with delays or impairments in language development. Readers will gain an understanding of the literature suggesting that early exposure to polychlorinated biphenyls (PCBs), lead, and mercury may be associated with decrements in cognitive domains that depend on language or are critical for language development. We also briefly summarize the smaller body of evidence regarding polybrominated diphenyl ether flame retardants (PBDEs) and organophosphate pesticides. Very few studies of exposure to these chemicals have used specific assessments of language development; thus, further investigation is needed before changes in clinical practice can be suggested. Copyright © 2015 Elsevier Inc. All rights reserved.

Reduction of scatter radiation during transradial percutaneous coronary angiography: a randomized trial using a lead-free radiation shield.

PubMed

Politi, Luigi; Biondi-Zoccai, Giuseppe; Nocetti, Luca; Costi, Tiziana; Monopoli, Daniel; Rossi, Rosario; Sgura, Fabio; Modena, Maria Grazia; Sangiorgi, Giuseppe M

2012-01-01

Occupational radiation exposure is a growing problem due to the increasing number and complexity of interventional procedures performed. Radial artery access has reduced the number of complications at the price of longer procedure duration. Radpad® scatter protection is a sterile, disposable bismuth-barium radiation shield drape that should be able to decrease the dose of operator radiation during diagnostic and interventional procedures. Such radiation shield has never been tested in a randomized study in humans. Sixty consecutive patients undergoing coronary angiography by radial approach were randomized 1:1 to Radpad use versus no radiation shield protection. The sterile shield was placed around the area of right radial artery sheath insertion and extended medially to the patient trunk. All diagnostic procedures were performed by the same operator to reduce variability in radiation absorption. Radiation exposure was measured blindly using thermoluminescence dosimeters positioned at the operator's chest, left eye, left wrist, and thyroid. Despite similar fluoroscopy time (3.52 ± 2.71 min vs. 3.46 ± 2.77 min, P = 0.898) and total examination dose (50.5 ± 30.7 vs. 45.8 ± 18.0 Gycm(2), P = 0.231), the mean total radiation exposure to the operator was significantly lower when Radpad was utilized (282.8 ± 32.55 μSv vs. 367.8 ± 105.4 μSv, P < 0.0001) corresponding to a 23% total reduction. Moreover, mean radiation exposure was lower with Radpad utilization at all body locations ranging from 13 to 34% reduction. This first-in-men randomized trial demonstrates that Radpad significantly reduces occupational radiation exposure during coronary angiography performed through right radial artery access. Copyright © 2011 Wiley Periodicals, Inc.

Telomere Length in Aged Mayak PA Nuclear Workers Chronically Exposed to Internal Alpha and External Gamma Radiation.

PubMed

Scherthan, Harry; Sotnik, Natalia; Peper, Michel; Schrock, Gerrit; Azizova, Tamara; Abend, Michael

2016-06-01

Telomeres consist of GC-rich DNA repeats and the "shelterin" protein complex that together protect chromosome ends from fusion and degradation. Telomeres shorten with age due to incomplete end replication and upon exposure to environmental and intrinsic stressors. Exposure to ionizing radiation is known to modulate telomere length. However, the response of telomere length in humans chronically exposed to radiation is poorly understood. Here, we studied relative telomere length (RTL) by IQ-FISH to leukocyte nuclei in a group of 100 workers from the plutonium production facility at the Mayak Production Association (PA) who were chronically exposed to alpha-emitting ((239)Pu) radiation and/or gamma (photon) radiation, and 51 local residents serving as controls, with a similar mean age of about 80 years. We applied generalized linear statistical models adjusted for age at biosampling and the second exposure type on a linear scale and observed an age-dependent telomere length reduction. In those individuals with the lowest exposure, a significant reduction of about 20% RTL was observed, both for external gamma radiation (≤1 Gy) and internal alpha radiation (≤0.05-0.1 Gy to the red bone marrow). In highly exposed individuals (>0.1 Gy alpha, 1-1.5 Gy gamma), the RTL was similar to control. Stratification by gender revealed a significant (∼30%) telomere reduction in low-dose-exposed males, which was absent in females. While the gender differences in RTL may reflect different working conditions, lifestyle and/or telomere biology, absence of a dose response in the highly exposed individuals may reflect selection against cells with short telomeres or induction of telomere-protective effects. Our observations suggest that chronic systemic exposure to radiation leads to variable dose-dependent effects on telomere length.

Effect of hydroxylamine on photon-like events during dark adaptation in toad rod photoreceptors.

PubMed Central

Leibrock, C S; Lamb, T D

1997-01-01

1. The suction pipette technique was used to investigate the recovery of toad rod photoreceptors following small bleaches of 0.2-3% of the rhodopsin. 2. The reduction in sensitivity and the increase in noise elicited by bleaches were measured, and from these measurements the underlying rate of occurrence of photon-like events was calculated as a function of time after the bleach. 3. Exposure to hydroxylamine solution was used to hasten the decomposition of the metarhodopsin photoproducts. The outer segment was exposed to 110 mM hydroxylamine in a low-Ca2+ Ringer solution for a period of 10-50 s beginning 10-17 min after the bleaching exposure. 4. By the time of the hydroxylamine exposure, the flash sensitivity and response kinetics had returned almost to normal, and were not significantly altered by the exposure. 5. Following hydroxylamine exposure, the rate of spontaneous photon-like events in the rods declined rapidly to near pre-bleach levels. 6. We conclude that hydroxylamine reduces the rate of occurrence of photon-like events induced by a bleach, and we postulate that this reduction results from the removal of metarhodopsin (most likely metarhodopsin II) from the outer segment. 7. Our results are consistent with a model in which photon-like events result from reversal of the reactions (phosphorylation and capping by arrestin) that lead to inactivation of the activated form of rhodopsin, Rh*. PMID:9174997

Metalloproteinase Inhibition Protects against Reductions in Circulating Adrenomedullin during Lead-induced Acute Hypertension.

PubMed

Nascimento, Regina A; Mendes, Gabryella; Possomato-Vieira, Jose S; Gonçalves-Rizzi, Victor Hugo; Kushima, Hélio; Delella, Flavia K; Dias-Junior, Carlos A

2015-06-01

Intoxication with lead (Pb) results in increased blood pressure by mechanisms involving matrix metalloproteinases (MMPs). Recent findings have revealed that MMP type two (MMP-2) seems to cleave vasoactive peptides. This study examined whether MMP-2 and MMP-9 levels/activities increase after acute intoxication with low lead concentrations and whether these changes were associated with increases in blood pressure and circulating endothelin-1 or with reductions in circulating adrenomedullin and calcitonin gene-related peptide (CGRP). Here, we expand previous findings and examine whether doxycycline (a MMPs inhibitor) affects these alterations. Wistar rats received intraperitoneally (i.p.) 1st dose 8 μg/100 g of lead (or sodium) acetate, a subsequent dose of 0.1 μg/100 g to cover daily loss and treatment with doxycycline (30 mg/kg/day) or water by gavage for 7 days. Similar whole-blood lead levels (9 μg/dL) were found in lead-exposed rats treated with either doxycycline or water. Lead-induced increases in systolic blood pressure (from 143 ± 2 to 167 ± 3 mmHg) and gelatin zymography of plasma samples showed that lead increased MMP-9 (but not MMP-2) levels. Both lead-induced increased MMP-9 activity and hypertension were blunted by doxycycline. Doxycycline also prevented lead-induced reductions in circulating adrenomedullin. No significant changes in plasma levels of endothelin-1 or CGRP were found. Lead-induced decreases in nitric oxide markers and antioxidant status were not prevented by doxycycline. In conclusion, acute lead exposure increases blood pressure and MMP-9 activity, which were blunted by doxycycline. These findings suggest that MMP-9 may contribute with lead-induced hypertension by cleaving the vasodilatory peptide adrenomedullin, thereby inhibiting adrenomedullin-dependent lowering of blood pressure. © 2014 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

Effective method of measuring the radioactivity of [ 131I]‐capsule prior to radioiodine therapy with significant reduction of the radiation exposure to the medical staff

PubMed Central

Lützen, Ulf; Zhao, Yi; Marx, Marlies; Imme, Thea; Assam, Isong; Siebert, Frank‐Andre; Culman, Juraj

2016-01-01

Radiation Protection in Radiology, Nuclear Medicine and Radio Oncology is of the utmost importance. Radioiodine therapy is a frequently used and effective method for the treatment of thyroid disease. Prior to each therapy the radioactivity of the [ 131I]‐capsule must be determined to prevent misadministration. This leads to a significant radiation exposure to the staff. We describe an alternative method, allowing a considerable reduction of the radiation exposure. Two [ 131I]‐capsules (A01=2818.5; A02=73.55.0 MBq) were measured multiple times in their own delivery lead containers — that is to say, [ 131I]‐capsules remain inside the containers during the measurements (shielded measurement) using a dose calibrator and a well‐type and a thyroid uptake probe. The results of the shielded measurements were correlated linearly with the [ 131I]‐capsules radioactivity to create calibration curves for the used devices. Additional radioactivity measurements of 50 [ 131I]‐capsules of different radioactivities were done to validate the shielded measuring method. The personal skin dose rate (HP(0.07)) was determined using calibrated thermo luminescent dosimeters. The determination coefficients for the calibration curves were R2>0.9980 for all devices. The relative uncertainty of the shielded measurement was <6.8%. At a distance of 10 cm from the unshielded capsule the HP(0.07) was 46.18 μSv/(GBq⋅s), and on the surface of the lead container containing the [ 131I]‐capsule the HP(0.07) was 2.99 and 0.27 μSv/(GBq⋅s) for the two used container sizes. The calculated reduction of the effective dose by using the shielded measuring method was, depending on the used container size, 74.0% and 97.4%, compared to the measurement of the unshielded [ 131I]‐capsule using a dose calibrator. The measured reduction of the effective radiation dose in the practice was 56.6% and 94.9 for size I and size II containers. The shielded [ 131I]‐capsule measurement reduces the radiation exposure to the staff significantly and offers the same accuracy of the unshielded measurement in the same amount of time. In order to maintain the consistency of the measuring method, monthly tests have to be done by measuring a [ 131I]‐capsule with known radioactivity. PACS number(s): 93.85.Np, 92.20.Td, 87.50.yk, 87.53.Bn PMID:27455475

Sub-chronic lead exposure produces β1-adrenoceptor downregulation decreasing arterial pressure reactivity in rats.

PubMed

Toscano, Cindy Medici; Simões, Maylla Ronacher; Alonso, Maria Jesus; Salaices, Mercedes; Vassallo, Dalton Valentim; Fioresi, Mirian

2017-07-01

Lead is considered a causative factor for hypertension and other cardiovascular diseases. To investigate the effects of sub-chronic lead exposure on blood pressure reactivity and cardiac β 1 -adrenoceptor activity and to evaluate whether the effects found in vitro are similar to those found in vivo. Male Wistar rats were randomly distributed into two groups: control rats (Ct) and rats administered drinking water containing 100ppm lead (Pb) for 30days. Blood pressure in the Pb rats increased starting from the first week of treatment until the end of the study [systolic blood pressure, Ct: 122±4 vs. Pb: 143±3mmHg; diastolic blood pressure, Ct: 63±4 vs. Pb: 84±4mmHg]. The heart rate was also increased (Ct: 299±11 vs. Pb: 365±11bpm), but the pressure reactivity to phenylephrine was decreased. Losartan and hexamethonium exhibited a greater reduction in blood pressure of Pb rats than in the Ct rats. Isoproterenol increased the left ventricular systolic and end-diastolic pressure, and heart rate only in Ct rats, suggesting that lead induced β 1 -adrenoceptor downregulation. Indomethacin reduced the blood pressure and heart rate in the Pb rats, suggesting the involvement of cyclooxygenase-derived products (which are associated with reduced nitric oxide bioavailability) in this process. These findings offer further evidence that the effects of sub-chronic lead exposure in vitro can be reproduced in vivo-even at low concentrations-thus triggering mechanisms for the development of hypertension. Therefore, lead should be considered an environmental risk factor for cardiovascular disease. Copyright © 2017 Elsevier Inc. All rights reserved.

Simultaneously reducing CO2 and particulate exposures via fractional recirculation of vehicle cabin air.

PubMed

Jung, Heejung S; Grady, Michael L; Victoroff, Tristan; Miller, Arthur L

2017-07-01

Prior studies demonstrate that air recirculation can reduce exposure to nanoparticles in vehicle cabins. However when people occupy confined spaces, air recirculation can lead to carbon dioxide (CO 2 ) accumulation which can potentially lead to deleterious effects on cognitive function. This study proposes a fractional air recirculation system for reducing nanoparticle concentration while simultaneously suppressing CO 2 levels in the cabin. Several recirculation scenarios were tested using a custom-programmed HVAC (heat, ventilation, air conditioning) unit that varied the recirculation door angle in the test vehicle. Operating the recirculation system with a standard cabin filter reduced particle concentrations to 1000 particles/cm 3 , although CO 2 levels rose to 3000 ppm. When as little as 25% fresh air was introduced (75% recirculation), CO 2 levels dropped to 1000 ppm, while particle concentrations remained below 5000 particles/cm 3 . We found that nanoparticles were removed selectively during recirculation and demonstrated the trade-off between cabin CO 2 concentration and cabin particle concentration using fractional air recirculation. Data showed significant increases in CO 2 levels during 100% recirculation. For various fan speeds, recirculation fractions of 50-75% maintained lower CO 2 levels in the cabin, while still reducing particulate levels. We recommend fractional recirculation as a simple method to reduce occupants' exposures to particulate matter and CO 2 in vehicles. A design with several fractional recirculation settings could allow air exchange adequate for reducing both particulate and CO 2 exposures. Developing this technology could lead to reductions in airborne nanoparticle exposure, while also mitigating safety risks from CO 2 accumulation.

Simultaneously reducing CO2 and particulate exposures via fractional recirculation of vehicle cabin air

PubMed Central

Jung, Heejung S.; Grady, Michael L.; Victoroff, Tristan; Miller, Arthur L.

2017-01-01

Prior studies demonstrate that air recirculation can reduce exposure to nanoparticles in vehicle cabins. However when people occupy confined spaces, air recirculation can lead to carbon dioxide (CO2) accumulation which can potentially lead to deleterious effects on cognitive function. This study proposes a fractional air recirculation system for reducing nanoparticle concentration while simultaneously suppressing CO2 levels in the cabin. Several recirculation scenarios were tested using a custom-programmed HVAC (heat, ventilation, air conditioning) unit that varied the recirculation door angle in the test vehicle. Operating the recirculation system with a standard cabin filter reduced particle concentrations to 1000 particles/cm3, although CO2 levels rose to 3000 ppm. When as little as 25% fresh air was introduced (75% recirculation), CO2 levels dropped to 1000 ppm, while particle concentrations remained below 5000 particles/cm3. We found that nanoparticles were removed selectively during recirculation and demonstrated the trade-off between cabin CO2 concentration and cabin particle concentration using fractional air recirculation. Data showed significant increases in CO2 levels during 100% recirculation. For various fan speeds, recirculation fractions of 50–75% maintained lower CO2 levels in the cabin, while still reducing particulate levels. We recommend fractional recirculation as a simple method to reduce occupants’ exposures to particulate matter and CO2 in vehicles. A design with several fractional recirculation settings could allow air exchange adequate for reducing both particulate and CO2 exposures. Developing this technology could lead to reductions in airborne nanoparticle exposure, while also mitigating safety risks from CO2 accumulation. PMID:28781568

Simultaneously reducing CO2 and particulate exposures via fractional recirculation of vehicle cabin air

NASA Astrophysics Data System (ADS)

Jung, Heejung S.; Grady, Michael L.; Victoroff, Tristan; Miller, Arthur L.

2017-07-01

Prior studies demonstrate that air recirculation can reduce exposure to nanoparticles in vehicle cabins. However when people occupy confined spaces, air recirculation can lead to carbon dioxide (CO2) accumulation which can potentially lead to deleterious effects on cognitive function. This study proposes a fractional air recirculation system for reducing nanoparticle concentration while simultaneously suppressing CO2 levels in the cabin. Several recirculation scenarios were tested using a custom-programmed HVAC (heat, ventilation, air conditioning) unit that varied the recirculation door angle in the test vehicle. Operating the recirculation system with a standard cabin filter reduced particle concentrations to 1000 particles/cm3, although CO2 levels rose to 3000 ppm. When as little as 25% fresh air was introduced (75% recirculation), CO2 levels dropped to 1000 ppm, while particle concentrations remained below 5000 particles/cm3. We found that nanoparticles were removed selectively during recirculation and demonstrated the trade-off between cabin CO2 concentration and cabin particle concentration using fractional air recirculation. Data showed significant increases in CO2 levels during 100% recirculation. For various fan speeds, recirculation fractions of 50-75% maintained lower CO2 levels in the cabin, while still reducing particulate levels. We recommend fractional recirculation as a simple method to reduce occupants' exposures to particulate matter and CO2 in vehicles. A design with several fractional recirculation settings could allow air exchange adequate for reducing both particulate and CO2 exposures. Developing this technology could lead to reductions in airborne nanoparticle exposure, while also mitigating safety risks from CO2 accumulation.

Efficacy of radiation safety glasses in interventional radiology.

PubMed

van Rooijen, Bart D; de Haan, Michiel W; Das, Marco; Arnoldussen, Carsten W K P; de Graaf, R; van Zwam, Wim H; Backes, Walter H; Jeukens, Cécile R L P N

2014-10-01

This study was designed to evaluate the reduction of the eye lens dose when wearing protective eyewear in interventional radiology and to identify conditions that optimize the efficacy of radiation safety glasses. The dose reduction provided by different models of radiation safety glasses was measured on an anthropomorphic phantom head. The influence of the orientation of the phantom head on the dose reduction was studied in detail. The dose reduction in interventional radiological practice was assessed by dose measurements on radiologists wearing either leaded or no glasses or using a ceiling suspended screen. The different models of radiation safety glasses provided a dose reduction in the range of a factor of 7.9-10.0 for frontal exposure of the phantom. The dose reduction was strongly reduced when the head is turned to the side relative to the irradiated volume. The eye closest to the tube was better protected due to side shielding and eyewear curvature. In clinical practice, the mean dose reduction was a factor of 2.1. Using a ceiling suspended lead glass shield resulted in a mean dose reduction of a factor of 5.7. The efficacy of radiation protection glasses depends on the orientation of the operator's head relative to the irradiated volume. Glasses can offer good protection to the eye under clinically relevant conditions. However, the performance in clinical practice in our study was lower than expected. This is likely related to nonoptimized room geometry and training of the staff as well as measurement methodology.

Perinatal Bisphenol A Exposure Induces Chronic Inflammation in Rabbit Offspring via Modulation of Gut Bacteria and Their Metabolites

PubMed Central

Veeramachaneni, D. N. Rao; Walters, William A.; Lozupone, Catherine; Palmer, Jennifer; Hewage, M. K. Kurundu; Bhatnagar, Rohil; Amir, Amnon; Kennett, Mary J.; Knight, Rob

2017-01-01

ABSTRACT Bisphenol A (BPA) accumulates in the maturing gut and liver in utero and is known to alter gut bacterial profiles in offspring. Gut bacterial dysbiosis may contribute to chronic colonic and systemic inflammation. We hypothesized that perinatal BPA exposure-induced intestinal (and liver) inflammation in offspring is due to alterations in the microbiome and colonic metabolome. The 16S rRNA amplicon sequencing analysis revealed differences in beta diversity with a significant reduction in the relative abundances of short-chain fatty acid (SCFA) producers such as Oscillospira and Ruminococcaceae due to BPA exposure. Furthermore, BPA exposure reduced fecal SCFA levels and increased systemic lipopolysaccharide (LPS) levels. BPA exposure-increased intestinal permeability was ameliorated by the addition of SCFA in vitro. Metabolic fingerprints revealed alterations in global metabolism and amino acid metabolism. Thus, our findings indicate that perinatal BPA exposure may cause gut bacterial dysbiosis and altered metabolite profiles, particularly SCFA profiles, leading to chronic colon and liver inflammation. IMPORTANCE Emerging evidence suggests that environmental toxicants may influence inflammation-promoted chronic disease susceptibility during early life. BPA, an environmental endocrine disruptor, can transfer across the placenta and accumulate in fetal gut and liver. However, underlying mechanisms for BPA-induced colonic and liver inflammation are not fully elucidated. In this report, we show how perinatal BPA exposure in rabbits alters gut microbiota and their metabolite profiles, which leads to colonic and liver inflammation as well as to increased gut permeability as measured by elevated serum lipopolysaccharide (LPS) levels in the offspring. Also, perinatal BPA exposure leads to reduced levels of gut bacterial diversity and bacterial metabolites (short-chain fatty acids [SCFA]) and elevated gut permeability—three common early biomarkers of inflammation-promoted chronic diseases. In addition, we showed that SCFA ameliorated BPA-induced intestinal permeability in vitro. Thus, our study results suggest that correcting environmental toxicant-induced bacterial dysbiosis early in life may reduce the risk of chronic diseases later in life. PMID:29034330

Emissions from residential energy use dominate exposure to ambient fine particulate matter in India

NASA Astrophysics Data System (ADS)

Conibear, L.; Butt, E. W.; Knote, C. J.; Arnold, S.; Spracklen, D. V.

2017-12-01

Exposure to ambient particulate matter of less than 2.5 µm in diameter (PM2.5) is a leading cause of disease burden in India. Information on the source contributions to the burden of disease attributable to ambient PM2.5 exposure is critical to support the national and sub-national control of air pollution. Previous studies analysing the contributions of different emission sectors to disease burden in India have been limited by coarse model resolutions and a lack of extensive PM2.5 observations before 2016. We use a regional numerical weather prediction model online-coupled with chemistry, evaluated against extensive surface observations, to make the first high resolution study of the contributions of seven emission sectors to the disease burden associated with ambient PM2.5 exposure in India. We find that residential energy use is the dominant contributing emission sector. Removing air pollution emissions from residential energy use would reduce population-weighted annual mean ambient PM2.5 concentrations by 52%, reducing the number of premature mortalities caused by exposure to ambient PM2.5 by 26%, equivalent to 268,000 (95% uncertainty interval (95UI): 167,000-360,000) lives every year. The smaller fractional reduction in mortality burden is due to the non-linear exposure-response relationship at the high PM2.5 concentrations observed across India and consequently large reductions in emissions are required to reduce the health burden from ambient PM2.5 exposure in India. Keywords: ambient air quality, India, residential energy use, health impact, particulate matter, WRF-Chem

Occupational Animal Allergy.

PubMed

Stave, Gregg M

2018-02-16

This review explores animal allergen exposure in research laboratories and other work settings, focusing on causes and prevention. (1) Consistent with the hygiene hypothesis, there is new evidence that early childhood exposure to pets produces changes in the gut microbiome that likely lead to a lower risk of allergy. (2) Anaphylaxis from laboratory animal bites occurs more frequently than suggested by prior literature. (3) Animal allergens represent an occupational hazard in a wide variety of work settings ranging from fields that work with animals to public settings like schools and public transportation where allergens are brought into or are present in the workplace. Exposure to animal allergens can result in allergy, asthma, and anaphylaxis. Animal allergy has been most studied in the research laboratory setting, where exposure reduction can prevent the development of allergy. Similar prevention approaches need to be considered for other animal work environments and in all settings where animal allergens are present.

Importance of Pipe Deposits to Lead and Copper Rule Compliance

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

Schock, Michael R.; Cantor, Abigail F.; Triantafyllidou, Simoni

When Madison, Wis., exceeded the lead action level in 1992, residential and off-line tests suggested that lead release into the water was more complex than a lead solubility mechanism. Scale analyses (color and texture as well as mineralogical and elemental composition) of five excavated lead service lines (LSLs) revealed that accumulation of manganese (and iron) onto pipe walls had implications for lead corrosion by providing a high-capacity sink for lead. Manganese that accumulated from source well water onto pipe scales (up to 10% by weight of scale composition) served to capture and eventually transport lead to consumer taps. In addition,more » manganese sometimes obstructed the predominance of an insoluble (and thus potentially protective) plattnerite [Pb(IV) solid] scale layer. Full LSL replacement in Madison achieved Lead and Copper Rule compliance and a major reduction in lead contamination and exposure, supplemented by unidirectional flushing of water mains and manganese control in the source well water.« less

[Hypersensitivity pneumonitis. A series of nine cases with surgical lung biopsy].

PubMed

Gómez Tejada, Ricardo A; Legarreta, Cora G; Enghelmayer, Juan Ignacio; Dianti, Milagros; Acuña, Silvana; Olmedo, Gloria

2017-01-01

In a series of nine patients with histopathological diagnosis of hypersensitivity pneumonitis, we retrospectively evaluated clinical data, exposure related factors, pulmonary function tests and chest computed tomography scans. A restrictive abnormality with reduction of diffusion capacity for carbon monoxide was mainly found. Chest scans showed fibrotic patterns in most cases; ground glass attenuation areas with mosaic pattern and consolidation in the rest. Exposure to avian antigens, cereal grains and air conditioners contaminated with fungi yeasts and bacteria, were suspected from clinical data in two-thirds of the cases. Since there are no unique features that allow differentiation from other interstitial lung diseases, a high clinical suspicion is required and a careful search of environmental exposure to possible antigens is needed that, together with clinical, radiological and pathological data, may lead to diagnosis.

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

PubMed

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

2017-04-01

Several cluster-randomized trials are underway to investigate the implementation and effectiveness of a universal test-and-treat strategy on the HIV epidemic in sub-Saharan Africa. We consider nesting studies of pre-exposure prophylaxis within these trials. Pre-exposure prophylaxis is a general strategy where high-risk HIV- persons take antiretrovirals daily to reduce their risk of infection from exposure to HIV. We address how to target pre-exposure prophylaxis to high-risk groups and how to maximize power to detect the individual and combined effects of universal test-and-treat and pre-exposure prophylaxis strategies. We simulated 1000 trials, each consisting of 32 villages with 200 individuals per village. At baseline, we randomized the universal test-and-treat strategy. Then, after 3 years of follow-up, we considered four strategies for targeting pre-exposure prophylaxis: (1) all HIV- individuals who self-identify as high risk, (2) all HIV- individuals who are identified by their HIV+ partner (serodiscordant couples), (3) highly connected HIV- individuals, and (4) the HIV- contacts of a newly diagnosed HIV+ individual (a ring-based strategy). We explored two possible trial designs, and all villages were followed for a total of 7 years. For each village in a trial, we used a stochastic block model to generate bipartite (male-female) networks and simulated an agent-based epidemic process on these networks. We estimated the individual and combined intervention effects with a novel targeted maximum likelihood estimator, which used cross-validation to data-adaptively select from a pre-specified library the candidate estimator that maximized the efficiency of the analysis. The universal test-and-treat strategy reduced the 3-year cumulative HIV incidence by 4.0% on average. The impact of each pre-exposure prophylaxis strategy on the 4-year cumulative HIV incidence varied by the coverage of the universal test-and-treat strategy with lower coverage resulting in a larger impact of pre-exposure prophylaxis. Offering pre-exposure prophylaxis to serodiscordant couples resulted in the largest reductions in HIV incidence (2% reduction), and the ring-based strategy had little impact (0% reduction). The joint effect was larger than either individual effect with reductions in the 7-year incidence ranging from 4.5% to 8.8%. Targeted maximum likelihood estimation, data-adaptively adjusting for baseline covariates, substantially improved power over the unadjusted analysis, while maintaining nominal confidence interval coverage. Our simulation study suggests that nesting a pre-exposure prophylaxis study within an ongoing trial can lead to combined intervention effects greater than those of universal test-and-treat alone and can provide information about the efficacy of pre-exposure prophylaxis in the presence of high coverage of treatment for HIV+ persons.

Will changes in phenology track climate change? A study of growth initiation timing in coast Douglas-fir

Treesearch

Kevin Ford; Connie Harrington; Sheel Bansal; Peter J. Gould; Brad St. Clair

2016-01-01

Under climate change, the reduction of frost risk, onset of warm temperatures and depletion of soil moisture are all likely to occur earlier in the year in many temperate regions. The resilience of tree species will depend on their ability to track these changes in climate with shifts in phenology that lead to earlier growth initiation in the spring. Exposure to warm...

Heterogeneity in Smokers' Responses to Tobacco Control Policies.

PubMed

Nesson, Erik

2017-02-01

This paper uses unconditional quantile regression to estimate whether smokers' responses to tobacco control policies change across the distribution of smoking levels. I measure smoking behavior with the number of cigarettes smoked per day and also with serum cotinine levels, a continuous biomarker of nicotine exposure, using individual-level repeated cross-section data from the National Health and Nutrition Examination Surveys. I find that the cigarette taxes lead to reductions in both the number of cigarettes smoked per day and in smokers' cotinine levels. These reductions are most pronounced in the middle quantiles of both distributions in terms of marginal effects, but most pronounced in the lower quantiles in terms of tax elasticities. I do not find that higher cigarette taxes lead to statistically significant changes in the amount of nicotine smokers ingest from each cigarette. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

The moving-window Bayesian maximum entropy framework: estimation of PM(2.5) yearly average concentration across the contiguous United States.

PubMed

Akita, Yasuyuki; Chen, Jiu-Chiuan; Serre, Marc L

2012-09-01

Geostatistical methods are widely used in estimating long-term exposures for epidemiological studies on air pollution, despite their limited capabilities to handle spatial non-stationarity over large geographic domains and the uncertainty associated with missing monitoring data. We developed a moving-window (MW) Bayesian maximum entropy (BME) method and applied this framework to estimate fine particulate matter (PM(2.5)) yearly average concentrations over the contiguous US. The MW approach accounts for the spatial non-stationarity, while the BME method rigorously processes the uncertainty associated with data missingness in the air-monitoring system. In the cross-validation analyses conducted on a set of randomly selected complete PM(2.5) data in 2003 and on simulated data with different degrees of missing data, we demonstrate that the MW approach alone leads to at least 17.8% reduction in mean square error (MSE) in estimating the yearly PM(2.5). Moreover, the MWBME method further reduces the MSE by 8.4-43.7%, with the proportion of incomplete data increased from 18.3% to 82.0%. The MWBME approach leads to significant reductions in estimation error and thus is recommended for epidemiological studies investigating the effect of long-term exposure to PM(2.5) across large geographical domains with expected spatial non-stationarity.

10 CFR 850.25 - Exposure reduction and minimization.

Code of Federal Regulations, 2010 CFR

2010-01-01

... § 850.25 Exposure reduction and minimization. (a) The responsible employer must ensure that no worker is exposed above the exposure limit prescribed in § 850.22. (b) The responsible employer must, in addition... described in the responsible employer's CBDPP and must include: (i) Annual goals for exposure reduction and...

IMPACT OF EMISSION REDUCTIONS ON EXPOSURES AND EXPOSURE DISTRIBUTIONS: APPLICATION OF A GEOGRAPHIC EXPOSURE MODEL

EPA Science Inventory

Anticipated results include the following. (1) We will estimate intake fraction (i.e., the fraction of emissions that are inhaled) for major source categories, over time, and by spatial location. Higher intake fraction indicates a greater exposure reduction per emission reduct...

Second hand tobacco smoke adversely affects the bone of immature rats

PubMed Central

Rosa, Rodrigo César; Pereira, Sângela Cunha; Cardoso, Fabrizio Antônio Gomide; Caetano, Abadio Gonçalves; de Santiago, Hildemberg Agostinho Rocha; Volpon, José Batista

2017-01-01

OBJECTIVES: To evaluate the influence of secondhand cigarette smoke exposure on longitudinal growth of the tibia of growing rats and some parameters of bone quality. METHODS: Forty female rats were randomly divided into four groups: control: rats were sham exposed; 30 days: rats were exposed to tobacco smoke for 30 days; 45 days: rats were exposed to tobacco smoke for 45 days; and 60 days: rats were exposed to tobacco smoke for 60 days. Blood samples were collected to evaluate the levels of cotinine and alkaline phosphatase. Both tibias were dissected and weighed; the lengths were measured, and the bones were then stored in a freezer for analysis of bone mineral content and mechanical resistance (maximal load and stiffness). RESULTS: Exposure of rats to tobacco smoke significantly compromised bone health, suggesting that the harmful effects may be time dependent. Harmful effects on bone growth were detected and were more pronounced at 60-day follow-ups with a 41.8% reduction in alkaline phosphatase levels (p<0.01) and a decrease of 11.25% in tibia length (p<0.001). Furthermore, a 41.5% decrease in bone mineral density was observed (p<0.001), leading to a 42.8% reduction in maximum strength (p<0.001) and a 56.7% reduction in stiffness (p<0.001). CONCLUSION: Second hand cigarette smoke exposure in rats affected bones that were weaker, deforming them and making them osteopenic. Additionally, the long bone was shorter, suggesting interference with growth. Such events seem to be related to time of exposure. PMID:29319726

Behavioral and Immunohistochemical Study of the Effects of Subchronic and Chronic Exposure to Glyphosate in Mice

PubMed Central

Ait Bali, Yassine; Ba-Mhamed, Saadia; Bennis, Mohamed

2017-01-01

Many epidemiological studies have described an adolescent-related psychiatric illness and sensorimotor deficits after Glyphosate based herbicide (GBH) exposure. GBH exposure in animal models of various ages suggests that it may be neurotoxic and could impact brain development and subsequently, behavior in adulthood. However, its neurotoxic effects on adolescent brain remain unclear and the results are limited. The present study was conducted to evaluate the neurobehavioral effects of GBH following acute, subchronic (6 weeks) and chronic (12 weeks) exposure (250 or 500 mg/kg/day) in mice treated from juvenile age until adulthood. Mice were subjected to behavioral testing with the open field (OF), the elevated plus maze, the tail suspension and Splash tests (STs). Their behaviors related to exploratory activity, anxiety and depression-like were recorded. After completion of the behavioral testing, adult mice were sacrificed and the expression of tyrosine hydroxylase (TH) in the substantia nigra pars compacta (SNc) and serotonin (5-HT) in the dorsal raphe nucleus (DRN), the basolateral amygdala (BLA) and the ventral medial prefrontal cortex (mPFC) was evaluated using immunohistochemical procedure. Our results indicate that unlike acute exposure, both subchronic and chronic exposure to GBH induced a decrease in body weight gain and locomotor activity, and an increase of anxiety and depression-like behavior levels. In addition, the immunohistochemical findings showed that only the chronic treatment induced a reduction of TH-immunoreactivity. However, both subchronic and chronic exposure produced a reduction of 5-HT-immunoreactivity in the DRN, BLA and ventral mPFC. Taken together, our data suggest that exposure to GBH from juvenile age through adulthood in mice leads to neurobehavioral changes that stem from the impairment of neuronal developmental processes. PMID:28848410

Efficacy of the RADPAD Protection Drape in Reducing Operators' Radiation Exposure in the Catheterization Laboratory: A Sham-Controlled Randomized Trial.

PubMed

Vlastra, Wieneke; Delewi, Ronak; Sjauw, Krischan D; Beijk, Marcel A; Claessen, Bimmer E; Streekstra, Geert J; Bekker, Robbert J; van Hattum, Juliette C; Wykrzykowska, Joanna J; Vis, Marije M; Koch, Karel T; de Winter, Robbert J; Piek, Jan J; Henriques, José P S

2017-11-01

Interventional cardiologists are increasingly exposed to radiation-induced diseases like cataract and the stochastic risk of left-sided brain tumors. The RADPAD is a sterile, disposable, lead-free shield placed on the patient with the aim to minimize operator-received scatter radiation. The objective of the trial was to examine the RADPAD's efficacy in a real-world situation. In the current, double-blind, sham-controlled, all-comer trial, patients undergoing diagnostic catheterization or percutaneous coronary interventions were randomized in a 1:1:1 ratio to a radiation absorbing shield (RADPAD), standard treatment (NOPAD), or a sham shield (SHAMPAD). The sham shield allowed testing for shield-induced radiation behavior. The primary outcome was the difference in relative exposure of the primary operator between the RADPAD and NOPAD arms and was defined as the ratio between operator's exposure (E in µSv) and patient exposure (dose area product in mGy·cm 2 ), measured per procedure. A total of 766 consecutive coronary procedures were randomized to the use of RADPAD (N=255), NOPAD (N=255), or SHAMPAD (N=256). The use of RADPAD was associated with a 20% reduction in relative operator exposure compared with that of NOPAD ( P =0.01) and a 44% relative exposure reduction compared with the use of a SHAMPAD ( P <0.001). Use of the SHAMPAD was associated with a 43% higher relative radiation exposure than procedures with NOPAD ( P =0.009). In clinical daily practice, the standard use of the RADPAD radiation shield reduced operator radiation exposure compared with procedures with NOPAD or SHAMPAD. This study supports the routine use of RADPAD in the catheterization laboratory. URL: https://www.clinicaltrials.gov. Unique identifier: NCT03139968. © 2017 American Heart Association, Inc.

The reduction of retinal autofluorescence caused by light exposure.

PubMed

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

2009-12-01

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

The Reduction of Retinal Autofluorescence Caused by Light Exposure

PubMed Central

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

2009-01-01

Purpose We have previously shown that long exposure to 568 nm light at levels below the maximum permissible exposure safety limit produces retinal damage preceded by a transient reduction in the autofluorescence of retinal pigment epithelial (RPE) cells in vivo. Here, we determine how the effects of exposure power and duration combine to produce this autofluorescence reduction and find the minimum exposure causing a detectable autofluorescence reduction. Methods Macaque retinas were imaged using a fluorescence adaptive optics scanning laser ophthalmoscope to resolve individual RPE cells in vivo. The retina was exposed to 568 nm light over a square subtending 0.5° with energies ranging from 1 J/cm2 to 788 J/cm2, where power and duration were independently varied. Results In vivo exposures of 5 J/cm2 and higher caused an immediate decrease in autofluorescence followed by either full autofluorescence recovery (exposures ≤ 210 J/cm2) or permanent RPE cell damage (exposures ≥ 247 J/cm2). No significant autofluorescence reduction was observed for exposures of 2 J/cm2 and lower. Reciprocity of exposure power and duration held for the exposures tested, implying that the total energy delivered to the retina, rather than its distribution in time, determines the amount of autofluorescence reduction. Conclusions That reciprocity holds is consistent with a photochemical origin, which may or may not cause retinal degeneration. The implementation of safe methods for delivering light to the retina requires a better understanding of the mechanism causing autofluorescence reduction. Finally, RPE imaging was demonstrated using light levels that do not cause a detectable reduction in autofluorescence. PMID:19628734

Impact of stressor exposure on the interplay between commensal microbiota and host inflammation.

PubMed

Galley, Jeffrey D; Bailey, Michael T

2014-01-01

Exposure to stressful stimuli results in the activation of multiple physiological processes aimed at maintaining homeostasis within the body. These physiological processes also have the capacity to influence the composition of microbial communities, and research now indicates that exposure to stressful stimuli leads to gut microbiota dysbiosis. While the relative abundance of many different bacterial types can be altered during stressor exposure, findings in nonhuman primates and laboratory rodents, as well as humans, indicate that bacteria in the genus Lactobacillus are consistently reduced in the gut during stress. The gut microbiota, including the lactobacilli, have many functions that enhance the health of the host. This review presents studies involving germfree and antibiotic treated mice, as well as mice given Lactobacillus spp. to prevent stressor-induced reductions in lactobacilli, to provide evidence that the microbiota contribute to stressor-induced immunomodulation, both in gut mucosa as well as in systemic compartments. This review will also discuss the evidence that commensal gut microbes have bidirectional effects on gastrointestinal physiology during stressor exposure.

Solar radiation and human health

NASA Astrophysics Data System (ADS)

Juzeniene, Asta; Brekke, Pål; Dahlback, Arne; Andersson-Engels, Stefan; Reichrath, Jörg; Moan, Kristin; Holick, Michael F.; Grant, William B.; Moan, Johan

2011-06-01

The Sun has played a major role in the development of life on Earth. In Western culture, people are warned against Sun exposure because of its adverse effects: erythema, photoimmunosuppression, photoageing, photocarcinogenesis, cataracts and photokeratitis. However, Sun exposure is also beneficial, since moderate doses give beneficial physiological effects: vitamin D synthesis, reduction of blood pressure and mental health. Shortage of Sun exposure may be even more dangerous to human health than excessive exposure. Avoiding Sun exposure leads to vitamin D deficiency which is associated not only with rickets and osteomalacia, but also with increased risk of cardiovascular disease, multiple sclerosis, rheumatoid arthritis, diabetes, influenza, many types of cancer and adverse pregnancy outcomes. Solar radiation induces nitric oxide release in tissue and immediate pigment darkening which certainly play important roles, although these are still unknown. Action spectra relevant for health are described. We will also review what is known about spectral and intensity variations of terrestrial solar radiation as well as its penetration through the atmosphere and into human skin and tissue.

Lead poisoning and the deceptive recovery of the critically endangered California condor

PubMed Central

Finkelstein, Myra E.; Doak, Daniel F.; George, Daniel; Burnett, Joe; Brandt, Joseph; Church, Molly; Grantham, Jesse; Smith, Donald R.

2012-01-01

Endangered species recovery programs seek to restore populations to self-sustaining levels. Nonetheless, many recovering species require continuing management to compensate for persistent threats in their environment. Judging true recovery in the face of this management is often difficult, impeding thorough analysis of the success of conservation programs. We illustrate these challenges with a multidisciplinary study of one of the world’s rarest birds—the California condor (Gymnogyps californianus). California condors were brought to the brink of extinction, in part, because of lead poisoning, and lead poisoning remains a significant threat today. We evaluated individual lead-related health effects, the efficacy of current efforts to prevent lead-caused deaths, and the consequences of any reduction in currently intensive management actions. Our results show that condors in California remain chronically exposed to harmful levels of lead; 30% of the annual blood samples collected from condors indicate lead exposure (blood lead ≥ 200 ng/mL) that causes significant subclinical health effects, measured as >60% inhibition of the heme biosynthetic enzyme δ-aminolevulinic acid dehydratase. Furthermore, each year, ∼20% of free-flying birds have blood lead levels (≥450 ng/mL) that indicate the need for clinical intervention to avert morbidity and mortality. Lead isotopic analysis shows that lead-based ammunition is the principle source of lead poisoning in condors. Finally, population models based on condor demographic data show that the condor’s apparent recovery is solely because of intensive ongoing management, with the only hope of achieving true recovery dependent on the elimination or substantial reduction of lead poisoning rates. PMID:22733770

Lead poisoning and the deceptive recovery of the critically endangered California condor.

PubMed

Finkelstein, Myra E; Doak, Daniel F; George, Daniel; Burnett, Joe; Brandt, Joseph; Church, Molly; Grantham, Jesse; Smith, Donald R

2012-07-10

Endangered species recovery programs seek to restore populations to self-sustaining levels. Nonetheless, many recovering species require continuing management to compensate for persistent threats in their environment. Judging true recovery in the face of this management is often difficult, impeding thorough analysis of the success of conservation programs. We illustrate these challenges with a multidisciplinary study of one of the world's rarest birds-the California condor (Gymnogyps californianus). California condors were brought to the brink of extinction, in part, because of lead poisoning, and lead poisoning remains a significant threat today. We evaluated individual lead-related health effects, the efficacy of current efforts to prevent lead-caused deaths, and the consequences of any reduction in currently intensive management actions. Our results show that condors in California remain chronically exposed to harmful levels of lead; 30% of the annual blood samples collected from condors indicate lead exposure (blood lead ≥ 200 ng/mL) that causes significant subclinical health effects, measured as >60% inhibition of the heme biosynthetic enzyme δ-aminolevulinic acid dehydratase. Furthermore, each year, ∼20% of free-flying birds have blood lead levels (≥450 ng/mL) that indicate the need for clinical intervention to avert morbidity and mortality. Lead isotopic analysis shows that lead-based ammunition is the principle source of lead poisoning in condors. Finally, population models based on condor demographic data show that the condor's apparent recovery is solely because of intensive ongoing management, with the only hope of achieving true recovery dependent on the elimination or substantial reduction of lead poisoning rates.

Mental Health Nurse’s Exposure to Workplace Violence Leads to Job Stress, Which Leads to Reduced Professional Quality of Life

PubMed Central

Itzhaki, Michal; Bluvstein, Irit; Peles Bortz, Anat; Kostistky, Hava; Bar Noy, Dor; Filshtinsky, Vivian; Theilla, Miriam

2018-01-01

Professional quality of life (ProQOL) reflects how individuals feel about their work as helpers. Psychiatric ward nurses cope with significant psychological and physical challenges, including exposure to verbal and physical violence. This study was based on two aspects of ProQOL, the positive compassion satisfaction, and the negative compassion fatigue, with the aim of investigating the relation of ProQOL to job stress and violence exposure at a large mental health center. Data were collected from 114 mental health nurses (49/63 M/F) who completed a self-administered questionnaire examining violence exposure, ProQOL, and job stress. The results showed that during the last year, almost all nurses (88.6%) experienced verbal violence, and more than half (56.1%) experienced physical violence. Only 2.6% experienced no violence. ProQOL was not associated with violence exposure but was reduced by work stress and by previous exposure to violence; nurses who perceived their work as more stressful had lower satisfaction from their work. In conclusion, although most mental health nurses are exposed to physical and verbal violence, their ProQOL is more related to job stress than to workplace violence (WPV). Hospital managements should conduct work stress reduction intervention programs and promote strategizes to reduce WPV. Further exploration of (a) factors affecting ProQOL and (b) the effect of violence coping workshops on ProQOL is warranted. PMID:29535652

Reduction of Phosphorylated Synapsin I (Ser-553) Leads to Spatial Memory Impairment by Attenuating GABA Release after Microwave Exposure in Wistar Rats

PubMed Central

Qiao, Simo; Peng, Ruiyun; Yan, Haitao; Gao, Yabing; Wang, Changzhen; Wang, Shuiming; Zou, Yong; Xu, Xinping; Zhao, Li; Dong, Ji; Su, Zhentao; Feng, Xinxin; Wang, Lifeng; Hu, Xiangjun

2014-01-01

Background Abnormal release of neurotransmitters after microwave exposure can cause learning and memory deficits. This study investigated the mechanism of this effect by exploring the potential role of phosphorylated synapsin I (p-Syn I). Methods Wistar rats, rat hippocampal synaptosomes, and differentiated (neuronal) PC12 cells were exposed to microwave radiation for 5 min at a mean power density of 30 mW/cm2. Sham group rats, synaptosomes, and cells were otherwise identically treated and acted as controls for all of the following post-exposure analyses. Spatial learning and memory in rats was assessed using the Morris Water Maze (MWM) navigation task. The protein expression and presynaptic distribution of p-Syn I and neurotransmitter transporters were examined via western blotting and immunoelectron microscopy, respectively. Levels amino acid neurotransmitter release from rat hippocampal synaptosomes and PC12 cells were measured using high performance liquid chromatograph (HPLC) at 6 hours after exposure, with or without synapsin I silencing via shRNA transfection. Results In the rat experiments, there was a decrease in spatial memory performance after microwave exposure. The expression of p-Syn I (ser-553) was decreased at 3 days post-exposure and elevated at later time points. Vesicular GABA transporter (VGAT) was significantly elevated after exposure. The GABA release from synaptosomes was attenuated and p-Syn I (ser-553) and VGAT were both enriched in small clear synaptic vesicles, which abnormally assembled in the presynaptic terminal after exposure. In the PC12 cell experiments, the expression of p-Syn I (ser-553) and GABA release were both attenuated at 6 hours after exposure. Both microwave exposure and p-Syn I silencing reduced GABA release and maximal reduction was found for the combination of the two, indicating a synergetic effect. Conclusion p-Syn I (ser-553) was found to play a key role in the impaired GABA release and cognitive dysfunction that was induced by microwave exposure. PMID:24743689

Reduction of phosphorylated synapsin I (ser-553) leads to spatial memory impairment by attenuating GABA release after microwave exposure in Wistar rats.

PubMed

Qiao, Simo; Peng, Ruiyun; Yan, Haitao; Gao, Yabing; Wang, Changzhen; Wang, Shuiming; Zou, Yong; Xu, Xinping; Zhao, Li; Dong, Ji; Su, Zhentao; Feng, Xinxin; Wang, Lifeng; Hu, Xiangjun

2014-01-01

Abnormal release of neurotransmitters after microwave exposure can cause learning and memory deficits. This study investigated the mechanism of this effect by exploring the potential role of phosphorylated synapsin I (p-Syn I). Wistar rats, rat hippocampal synaptosomes, and differentiated (neuronal) PC12 cells were exposed to microwave radiation for 5 min at a mean power density of 30 mW/cm2. Sham group rats, synaptosomes, and cells were otherwise identically treated and acted as controls for all of the following post-exposure analyses. Spatial learning and memory in rats was assessed using the Morris Water Maze (MWM) navigation task. The protein expression and presynaptic distribution of p-Syn I and neurotransmitter transporters were examined via western blotting and immunoelectron microscopy, respectively. Levels amino acid neurotransmitter release from rat hippocampal synaptosomes and PC12 cells were measured using high performance liquid chromatograph (HPLC) at 6 hours after exposure, with or without synapsin I silencing via shRNA transfection. In the rat experiments, there was a decrease in spatial memory performance after microwave exposure. The expression of p-Syn I (ser-553) was decreased at 3 days post-exposure and elevated at later time points. Vesicular GABA transporter (VGAT) was significantly elevated after exposure. The GABA release from synaptosomes was attenuated and p-Syn I (ser-553) and VGAT were both enriched in small clear synaptic vesicles, which abnormally assembled in the presynaptic terminal after exposure. In the PC12 cell experiments, the expression of p-Syn I (ser-553) and GABA release were both attenuated at 6 hours after exposure. Both microwave exposure and p-Syn I silencing reduced GABA release and maximal reduction was found for the combination of the two, indicating a synergetic effect. p-Syn I (ser-553) was found to play a key role in the impaired GABA release and cognitive dysfunction that was induced by microwave exposure.

Evaluation and assessment of the efficacy of an abatement strategy in a former lead smelter community, Boolaroo, Australia.

PubMed

Harvey, P J; Taylor, M P; Kristensen, L J; Grant-Vest, S; Rouillon, M; Wu, L; Handley, H K

2016-08-01

This study examines the recent soil Lead Abatement Strategy (LAS) in Boolaroo, New South Wales, Australia, that was designed to "achieve a reduction in human exposure to lead dust contamination in surface soils". The abatement programme addressed legacy contamination of residential areas following closure of lead smelting operations in 2003 at the Pasminco Cockle Creek Smelter (PCCS). The principal objective of the LAS was to "cap and cover" lead-contaminated soils within the urban environment surrounding the PCCS. Soil lead concentrations of 2500-5000 mg/kg were scheduled for removal and replacement, while concentrations between 1500 and 2500 mg/kg were replaced only under limited circumstances. To date, there has been no industry, government or independent assessment of the clean-up programme that involved >2000 homes in the township of Boolaroo. Thus, by measuring post-abatement soil lead concentrations in Boolaroo, this study addresses this knowledge gap and evaluates the effectiveness of the LAS for reducing the potential for lead exposure. Soil lead concentrations above the Australian residential soil health investigation level value for residential soils (300 mg/kg) were identified at all but one of the residential properties examined (n = 19). Vacuum dust samples (n = 17) from the same homes had a mean lead concentration of 495 mg/kg (median 380 mg/kg). Bio-accessibility testing revealed that lead in household vacuum dust was readily accessible (% bio-accessible) (mean = 92 %, median = 90 %), demonstrating that the risk of exposure via this pathway remains. Assessment of a limited number of properties (n = 8) where pre-abatement soil lead levels were available for comparison showed they were not statistically different to post-abatement. Although the LAS did not include treatment of non-residential properties, sampling of community areas including public sports fields, playgrounds and schools (n = 32) was undertaken to determine the contamination legacy in these areas. Elevated mean soil lead concentrations were found across public lands: sports fields = 5130 mg/kg (median = 1275 mg/kg), playgrounds and schools = 812 mg/kg (median = 920 mg/kg) and open space = 778 mg/kg (median = 620 mg/kg). Overall, the study results show that the LAS programme that was dominated by a "cap and cover" approach to address widespread lead contamination was inadequate for mitigating current and future risk of lead exposures.

Prevalence and determinants of lead intoxication in Mexican children of low socioeconomic status.

PubMed Central

López-Carrillo, L; Torres-Sánchez, L; Garrido, F; Papaqui-Hernández, J; Palazuelos-Rendón, E; López-Cervantes, M

1996-01-01

This paper reports on the prevalence of lead poisoning in children between 1 and 5 years of age living in a marginal area to the north of Mexico City and also includes an evaluation of sources of exposure to this metal in the same area. The results show that 67.5% of the children studied have blood lead (PbB) levels > or = 10 micrograms/100 ml. Twenty-one percent of these children (1987) had PbB levels that required medical evaluation (> or = 20 micrograms/100 ml- < or = 40 micrograms/100 ml), and 112 children needed medical treatment (PbB > or = 40 micrograms/100 ml). In addition, the study found that the probability of higher blood lead levels (> or = 20 micrograms/dl) corresponds to children whose mothers use lead-glazed pottery dishes (OR = 2.80; CI 95%, 1.55-5.07) and to children who habitually bite colored pencils (OR = 2.05; CI 95%, 1.13-3.71) compared, respectively, with children whose mothers do not use that type of dishes and children who do not bite pencils. Our results provide baseline information for estimating the impact and costs of population-based interventions aimed at these populations and also confirm the need to strengthen health education programs to promote the reduction of lead exposure in the general population. PMID:8959410

Combined pesticide exposure severely affects individual- and colony-level traits in bees

PubMed Central

Gill, Richard J.; Ramos-Rodriguez, Oscar; Raine, Nigel E.

2012-01-01

Reported widespread declines of wild and managed insect pollinators have serious consequences for global ecosystem services and agricultural production1-3. Bees contribute around 80% of insect pollination, so it is imperative we understand and mitigate the causes of current declines4-6. Recent studies have implicated the role of pesticides as exposure to these chemicals has been associated with changes in bee behaviour7-11 and reductions in colony queen production12. However the key link between changes in individual behaviour and consequent impact at the colony level has not been shown. Social bee colonies depend on the collective performance of numerous individual workers. So whilst field-level pesticide concentrations can have a subtle/sublethal effect at the individual level8, it is not known whether bee societies can buffer such effects or if it results in a severe cumulative effect at the colony level. Furthermore, widespread agricultural intensification means bees are exposed to numerous pesticides when foraging13-15, yet the possible combinatorial effects of pesticide exposure have rarely been investigated16,17. Here we show that chronic exposure of bumblebees to two pesticides (neonicotinoid and pyrethroid) at concentrations that could approximate field-level exposure impairs natural foraging behaviour and increases worker mortality leading to significant reductions in brood development and colony success. We found worker foraging performance, particularly pollen collecting efficiency, was significantly reduced with observed knock-on effects for forager recruitment, worker losses and overall worker productivity. Moreover, we provide evidence that combinatorial exposure to pesticides increases the propensity of colonies to fail. PMID:23086150

Effectiveness of interventions to reduce exposure to lead through consumer products and drinking water: A systematic review.

PubMed

Pfadenhauer, Lisa Maria; Burns, Jacob; Rohwer, Anke; Rehfuess, Eva Annette

2016-05-01

The objective of this systematic review is to assess the effectiveness of regulatory, environmental and educational interventions for reducing blood lead levels (BLLs) and associated health outcomes in children, pregnant women and the general population. Searches were run in MEDLINE, EMBASE and the Global Health Library up until August 2015. Studies were eligible for inclusion if they assessed the impact of regulatory, environmental or educational interventions, stand-alone or in combination, on BLLs among children, pregnant women or the general population through randomized controlled trials (RCT), controlled before-after (CBA), interrupted time series (ITS), uncontrolled before-after (UBA) or repeated cross-sectional studies. Studies assessing the impact of interventions to reduce exposure to lead in paint or household dust as well as studies concerned exclusively with environmental concentrations of lead were not included. As documented in a detailed protocol, screening, data extraction and quality appraisal were largely undertaken according to Cochrane standards. Harvest plots were used to graphically summarize evidence of effectiveness. The searches yielded 6466 unique records, of which five met our eligibility criteria; two additional eligible studies were identified by experts. We did not find any studies regarding the effectiveness of regulatory, educational or environmental interventions targeting exposure to lead in consumer products. Evidence regarding the effectiveness of interventions in reducing BLLs from exposures through drinking water is limited in both quantity and quality. Stand-alone targeted educational interventions showed no statistically significant reductions in children's BLL (two RCT) when compared to general educational interventions. Likewise, instructing women to reduce or eliminate lead-contaminated drinking water showed no effect on BLL (one RCT). Stand-alone environmental interventions appeared more promising in reducing BLL (three UBA). Combining educational and environmental interventions and targeting multiple settings may be effective in reducing BLL, as suggested by one uncontrolled before-after study. No studies examining the effectiveness of regulatory interventions were found. The limited quantity and quality of the evidence measuring BLL and associated health outcomes points to an urgent need for more robust research into the effectiveness of interventions to reduce lead exposure from consumer products and drinking water, especially for regulatory interventions. Copyright © 2016 Elsevier Inc. All rights reserved.

Elevated blood lead levels in refugee children--New Hampshire, 2003-2004.

PubMed

2005-01-21

As a result of reductions in lead hazards and improved screening practices, blood lead levels (BLLs) in children aged 1-5 years are decreasing in the United States. However, the risk for elevated BLLs (> or =10 microg/dL) remains high for certain populations, including refugees. After the death of a Sudanese refugee child from lead poisoning in New Hampshire in 2000, the New Hampshire Department of Health and Human Services (NHDHHS) developed lead testing guidelines to screen and monitor refugee children. These guidelines recommend 1) capillary blood lead testing for refugee children aged 6 months-15 years within 3 months after arrival in New Hampshire, 2) follow-up venous testing of children aged <6 years within 3-6 months after initial screening, and 3) notation of refugee status on laboratory slips for first tests. In 2004, routine laboratory telephone reports of elevated BLLs to the New Hampshire Childhood Lead Poisoning Prevention Program (NHCLPPP) called attention to a pattern of elevated BLLs among refugee children. To develop prevention strategies, NHDHHS analyzed NHCLPPP and Manchester Health Department (MHD) data, focusing on the 37 African refugee children with elevated BLLs on follow-up for whom complete data were available. This report describes the results of that analysis, which indicated that 1) follow-up blood lead testing is useful to identify lead exposure that occurs after resettlement and 2) refugee children in New Hampshire older than those routinely tested might have elevated BLLs. Refugee children in all states should be tested for lead poisoning on arrival and several months after initial screening to assess exposure after resettlement.

Assessment of Child Lead Exposure in a Philadelphia Community, 2014.

PubMed

Dignam, Timothy; Pomales, Ana; Werner, Lora; Newbern, E Claire; Hodge, James; Nielsen, Jay; Grober, Aaron; Scruton, Karen; Young, Rand; Kelly, Jack; Brown, Mary Jean

2018-01-10

Several urban neighborhoods in Philadelphia, Pennsylvania, have a history of soil, household lead paint, and potential lead-emitting industry contamination. To (1) describe blood lead levels (BLLs) in target neighborhoods, (2) identify risk factors and sources of lead exposure, (3) describe household environmental lead levels, and (4) compare results with existing data. A simple, random, cross-sectional sampling strategy was used to enroll children 8 years or younger living in selected Philadelphia neighborhoods with a history of lead-emitting industry during July 2014. Geometric mean of child BLLs and prevalence of BLLs of 5 μg/dL or more were calculated. Linear and logistic regression analyses were used to ascertain risk factors for elevated BLLs. Among 104 children tested for blood lead, 13 (12.4%; 95% confidence interval [CI], 7.5-20.2) had BLLs of 5 μg/dL or more. The geometric mean BLL was 2.0 μg/dL (95% CI, 1.7-2.3 μg/dL). Higher geometric mean BLLs were significantly associated with front door entryway dust lead content, residence built prior to 1900, and a child currently or ever receiving Medicaid. Seventy-one percent of households exceeded the screening level for soil, 25% had an elevated front door floor dust lead level, 28% had an elevated child play area floor dust lead level, and 14% had an elevated interior window dust lead level. Children in households with 2 to 3 elevated environmental lead samples were more likely to have BLLs of 5 μg/dL or more. A spatial relationship between household proximity to historic lead-emitting facilities and child BLL was not identified. Entryway floor dust lead levels were strongly associated with blood lead levels in participants. Results underscore the importance to make housing lead safe by addressing all lead hazards in and around the home. Reduction of child lead exposure is crucial, and continued blood lead surveillance, testing, and inspection of homes of children with BLLs of 5 μg/dL or more to identify and control lead sources are recommended. Pediatric health care providers can be especially vigilant screening Medicaid-eligible/enrolled children and children living in very old housing.

Exposure Perception as a Key Indicator of Risk Perception and Acceptance of Sources of Radio Frequency Electromagnetic Fields.

PubMed

Freudenstein, Frederik; Wiedemann, Peter M; Brown, Tim W C

2015-01-01

The presented survey was conducted in six European countries as an online study. A total of 2454 subjects participated. Two main research questions were investigated: firstly, how does the cognitive, moral, and affective framing of radio frequency electromagnetic field (RF EMF) exposure perception influence RF EMF risk perception? Secondly, can the deployment of mobile phone base stations have greater acceptance with RF EMF exposure reduction? The findings with respect to the first question clearly indicated that the cognitive framed exposure perception is the main determinant of RF EMF risk perception. The concomitant sensitivity to exposure strength offers an opportunity to improve the acceptance of base stations by exposure reduction. A linear regression analysis supported this assumption: in a fictional test situation, exposure reduction improved the acceptance of base stations, operationalized as the requested distance of the base station from one's own home. Furthermore, subjects with high RF EMF risk perception were most sensitive to exposure reduction. On average, a 70% exposure reduction reduced the requested distance from about 2000 meters to 1000 meters. The consequences for risk communication are discussed.

Long-term food-exposure of zebrafish to PCB mixtures mimicking some environmental situations induces ovary pathology and impairs reproduction ability.

PubMed

Daouk, Tarek; Larcher, Thibaut; Roupsard, François; Lyphout, Laura; Rigaud, Cyril; Ledevin, Mireille; Loizeau, Véronique; Cousin, Xavier

2011-10-01

Although the use of polychlorinated biphenyls (PCBs) has been banned for several decades, they are still present in the environment and are occasionally mechanically released from sediment or transferred through the trophic chain. Field analyses have established correlations between exposure to PCBs and alterations in fish physiology including reproductive function. Experimental exposures have been mainly performed using dioxin-like PCBs or other congeners at very high concentrations. However, these studies are often difficult to relate to real-life conditions. In the present study, we performed a life-cycle exposure using zebrafish model and mixtures representative of some environmental situations in terms of doses, composition and containing mainly non dioxin-like congeners. Exposure was performed through diet which is the main contamination route in the field. We demonstrated a bioaccumulation of PCBs in males and females as well as a maternal transfer to the eggs. Survival, growth and organ size were similar for all conditions. Several reproductive traits were altered after exposure to a PCB-contaminated diet, including a reduction in the number of fertilized eggs per spawn as well as an increase of the number of poorly fertilized spawns. This latter observation was found irrespective of the sex of contaminated fish. This is related to modifications of ovary histology revealing a decrease of maturing follicles and an increase of atretic follicles in the ovaries of females exposed to PCBs. These results indicate that exposure to PCBs mixtures mimicking some environmental situations, including mainly non dioxin-like congeners, can lead to a dramatic reduction in the number of offspring produced by a female over a lifetime. This is of great concern for wild species living under natural conditions. Copyright © 2011 Elsevier B.V. All rights reserved.

Protective hybrid coating containing silver, copper and zinc cations effective against human immunodeficiency virus and other enveloped viruses.

PubMed

Hodek, Jan; Zajícová, Veronika; Lovětinská-Šlamborová, Irena; Stibor, Ivan; Müllerová, Jana; Weber, Jan

2016-04-01

Healthcare-acquired infections by pathogenic microorganisms including viruses represent significant health concern worldwide. Next to direct transmission from person-to-person also indirect transmission from contaminated surfaces is well documented and important route of infections. Here, we tested antiviral properties of hybrid coating containing silver, copper and zinc cations that was previously shown to be effective against pathogenic bacteria including methicillin-resistant Staphylococcus aureus. Hybrid coatings containing silver, copper and zinc cations were prepared through radical polymerization via sol-gel method and applied on glass slides or into the wells of polymethylmethacrylate plates. A 10 μl droplet of several viruses such as human immunodeficiency virus type 1 (HIV-1), influenza, dengue virus, herpes simplex virus, and coxsackievirus was added to coated and uncoated slides or plates, incubated usually from 5 to 240 min and followed by titer determination of recovered virus. Scanning electron microscopy analysis showed better adhesion of coatings on glass surfaces, which resulted in 99.5-100 % HIV-1 titer reduction (3.1 ± 0.8 log10TCID50, n = 3) already after 20 min of exposure to coatings, than on coated polymethylmethacrylate plates with 75-100 % (1.7 ± 1.1 log10TCID50, n = 3) and 98-100 % (2.3 ± 0.5 log10TCID50, n = 3) HIV-1 titer reduction after 20 and 120 min of exposure, respectively. Slower virucidal kinetics was observed with other enveloped viruses, where 240 min exposure to coated slides lead to 97 % (dengue), 100 % (herpes simplex) and 77 % (influenza) reduction in virus titers. Interestingly, only marginal reduction in viral titer after 240 min of exposure was noticed for non-enveloped coxsackie B3 virus. Our hybrid coatings showed virucidal activity against HIV and other enveloped viruses thus providing further findings towards development of broad-spectrum antimicrobial coating suitable for surfaces in healthcare settings.

Effects of lead on the male mouse as investigated by in vitro fertilization and blastocyst culture

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

Johansson, L.; Sjoeblom, P.; Wide, M.

1987-02-01

Long-term exposure of male mice to inorganic lead (lead chloride, 1 g/liter) in the drinking water reduces their fertility. The cause of this reduction, expressed as a decrease in the number of mated females showing inplantations, was investigated, using an in vivo fertilization method. It was found that spermatozoa from lead-exposed males had a significantly lower ability to fertilize mouse eggs than those from unexposed males. Preimplantation embryos, isolated from uterine horns of mice mated with lead-exposed males. Preimplantation embryos, isolated from uterine horns of mice mated with lead-exposed males, were examined. No morphologically abnormal embryos were found. However, whenmore » cultured in vitro over the implantation period, blastocysts of the group mated with lead-exposed males showed an increased frequency of delayed hatching from the zona pellucida or an inability to hatch. Among blastocysts from this group a decreased frequency of inner cell mass development was also found.« less

Modulation of population density and size of silver nanoparticles embedded in bacterial cellulose via ammonia exposure: visual detection of volatile compounds in a piece of plasmonic nanopaper

NASA Astrophysics Data System (ADS)

Heli, B.; Morales-Narváez, E.; Golmohammadi, H.; Ajji, A.; Merkoçi, A.

2016-04-01

The localized surface plasmon resonance exhibited by noble metal nanoparticles can be sensitively tuned by varying their size and interparticle distances. We report that corrosive vapour (ammonia) exposure dramatically reduces the population density of silver nanoparticles (AgNPs) embedded within bacterial cellulose, leading to a larger distance between the remaining nanoparticles and a decrease in the UV-Vis absorbance associated with the AgNP plasmonic properties. We also found that the size distribution of AgNPs embedded in bacterial cellulose undergoes a reduction in the presence of volatile compounds released during food spoilage, modulating the studied nanoplasmonic properties. In fact, such a plasmonic nanopaper exhibits a change in colour from amber to light amber upon the explored corrosive vapour exposure and from amber to a grey or taupe colour upon fish or meat spoilage exposure. These phenomena are proposed as a simple visual detection of volatile compounds in a flexible, transparent, permeable and stable single-use nanoplasmonic membrane, which opens the way to innovative approaches and capabilities in gas sensing and smart packaging.The localized surface plasmon resonance exhibited by noble metal nanoparticles can be sensitively tuned by varying their size and interparticle distances. We report that corrosive vapour (ammonia) exposure dramatically reduces the population density of silver nanoparticles (AgNPs) embedded within bacterial cellulose, leading to a larger distance between the remaining nanoparticles and a decrease in the UV-Vis absorbance associated with the AgNP plasmonic properties. We also found that the size distribution of AgNPs embedded in bacterial cellulose undergoes a reduction in the presence of volatile compounds released during food spoilage, modulating the studied nanoplasmonic properties. In fact, such a plasmonic nanopaper exhibits a change in colour from amber to light amber upon the explored corrosive vapour exposure and from amber to a grey or taupe colour upon fish or meat spoilage exposure. These phenomena are proposed as a simple visual detection of volatile compounds in a flexible, transparent, permeable and stable single-use nanoplasmonic membrane, which opens the way to innovative approaches and capabilities in gas sensing and smart packaging. Electronic supplementary information (ESI) available: Details on the estimations of evaporation rates and limits of detection, ESI figures and author contributions. See DOI: 10.1039/c6nr00537c

Maternal choline supplementation in a sheep model of first trimester binge alcohol fails to protect against brain volume reductions in peripubertal lambs.

PubMed

Birch, Sharla M; Lenox, Mark W; Kornegay, Joe N; Paniagua, Beatriz; Styner, Martin A; Goodlett, Charles R; Cudd, Tim A; Washburn, Shannon E

2016-09-01

Fetal alcohol spectrum disorder (FASD) is a leading potentially preventable birth defect. Poor nutrition may contribute to adverse developmental outcomes of prenatal alcohol exposure, and supplementation of essential micronutrients such as choline has shown benefit in rodent models. The sheep model of first-trimester binge alcohol exposure was used in this study to model the dose of maternal choline supplementation used in an ongoing prospective clinical trial involving pregnancies at risk for FASD. Primary outcome measures including volumetrics of the whole brain, cerebellum, and pituitary derived from magnetic resonance imaging (MRI) in 6-month-old lambs, testing the hypothesis that alcohol-exposed lambs would have brain volume reductions that would be ameliorated by maternal choline supplementation. Pregnant sheep were randomly assigned to one of five groups - heavy binge alcohol (HBA; 2.5 g/kg/treatment ethanol), heavy binge alcohol plus choline supplementation (HBC; 2.5 g/kg/treatment ethanol and 10 mg/kg/day choline), saline control (SC), saline control plus choline supplementation (SCC; 10 mg/kg/day choline), and normal control (NC). Ewes were given intravenous alcohol (HBA, HBC; mean peak BACs of ∼280 mg/dL) or saline (SC, SCC) on three consecutive days per week from gestation day (GD) 4-41; choline was administered on GD 4-148. MRI scans of lamb brains were performed postnatally on day 182. Lambs from both alcohol groups (with or without choline) showed significant reductions in total brain volume; cerebellar and pituitary volumes were not significantly affected. This is the first report of MRI-derived volumetric brain reductions in a sheep model of FASD following binge-like alcohol exposure during the first trimester. These results also indicate that maternal choline supplementation comparable to doses in human studies fails to prevent brain volume reductions typically induced by first-trimester binge alcohol exposure. Future analyses will assess behavioral outcomes along with regional brain and neurohistological measures. Copyright © 2016 Elsevier Inc. All rights reserved.

Dose-Response Relationship between Cumulative Occupational Lead Exposure and the Associated Health Damages: A 20-Year Cohort Study of a Smelter in China

PubMed Central

Wu, Yue; Gu, Jun-Ming; Huang, Yun; Duan, Yan-Ying; Huang, Rui-Xue; Hu, Jian-An

2016-01-01

Long-term airborne lead exposure, even below official occupational limits, has been found to cause lead poisoning at higher frequencies than expected, which suggests that China’s existing occupational exposure limits should be reexamined. A retrospective cohort study was conducted on 1832 smelting workers from 1988 to 2008 in China. These were individuals who entered the plant and came into continuous contact with lead at work for longer than 3 months. The dose-response relationship between occupational cumulative lead exposure and lead poisoning, abnormal blood lead, urinary lead and erythrocyte zinc protoporphyrin (ZPP) were analyzed and the benchmark dose lower bound confidence limits (BMDLs) were calculated. Statistically significant positive correlations were found between cumulative lead dust and lead fumes exposures and workplace seniority, blood lead, urinary lead and ZPP values. A dose-response relationship was observed between cumulative lead dust or lead fumes exposure and lead poisoning (p < 0.01). The BMDLs of the cumulative occupational lead dust and fumes doses were 0.68 mg-year/m3 and 0.30 mg-year/m3 for lead poisoning, respectively. The BMDLs of workplace airborne lead concentrations associated with lead poisoning were 0.02 mg/m3 and 0.01 mg/m3 for occupational exposure lead dust and lead fume, respectively. In conclusion, BMDLs for airborne lead were lower than occupational exposure limits, suggesting that the occupational lead exposure limits need re-examination and adjustment. Occupational cumulative exposure limits (OCELs) should be established to better prevent occupational lead poisoning. PMID:26999177

Health Impact Assessment for Second-Hand Smoke Exposure in Germany--Quantifying Estimates for Ischaemic Heart Diseases, COPD, and Stroke.

PubMed

Fischer, Florian; Kraemer, Alexander

2016-02-05

Evidence of the adverse health effects attributable to second-hand smoke (SHS) exposure is available. This study aims to quantify the impact of SHS exposure on ischaemic heart diseases (IHD), chronic obstructive pulmonary diseases (COPD), and stroke in Germany. Therefore, this study estimated and forecasted the morbidity for the three outcomes in the German population. Furthermore, a health impact assessment was performed using DYNAMO-HIA, which is a generic software tool applying a Markov model. Overall 687,254 IHD cases, 231,973 COPD cases, and 288,015 stroke cases were estimated to be attributable to SHS exposure in Germany for 2014. Under the assumption that the population prevalence of these diseases and the prevalence of SHS exposure remain constant, the total number of cases will increase due to demographic aging. Assuming a total eradication of SHS exposure beginning in 2014 leads to an estimated reduction of 50% in cases, compared to the reference scenario in 2040 for all three diseases. The results highlight the relevance of SHS exposure because it affects several chronic disease conditions and has a major impact on the population's health. Therefore, public health campaigns to protect non-smokers are urgently needed.

Lead exposure in US worksites: A literature review and development of an occupational lead exposure database from the published literature

PubMed Central

Koh, Dong-Hee; Locke, Sarah J.; Chen, Yu-Cheng; Purdue, Mark P.; Friesen, Melissa C.

2016-01-01

Background Retrospective exposure assessment of occupational lead exposure in population-based studies requires historical exposure information from many occupations and industries. Methods We reviewed published US exposure monitoring studies to identify lead exposure measurement data. We developed an occupational lead exposure database from the 175 identified papers containing 1,111 sets of lead concentration summary statistics (21% area air, 47% personal air, 32% blood). We also extracted ancillary exposure-related information, including job, industry, task/location, year collected, sampling strategy, control measures in place, and sampling and analytical methods. Results Measurements were published between 1940 and 2010 and represented 27 2-digit standardized industry classification codes. The majority of the measurements were related to lead-based paint work, joining or cutting metal using heat, primary and secondary metal manufacturing, and lead acid battery manufacturing. Conclusions This database can be used in future statistical analyses to characterize differences in lead exposure across time, jobs, and industries. PMID:25968240

Exposure Perception as a Key Indicator of Risk Perception and Acceptance of Sources of Radio Frequency Electromagnetic Fields

PubMed Central

Wiedemann, Peter M.; Brown, Tim W. C.

2015-01-01

The presented survey was conducted in six European countries as an online study. A total of 2454 subjects participated. Two main research questions were investigated: firstly, how does the cognitive, moral, and affective framing of radio frequency electromagnetic field (RF EMF) exposure perception influence RF EMF risk perception? Secondly, can the deployment of mobile phone base stations have greater acceptance with RF EMF exposure reduction? The findings with respect to the first question clearly indicated that the cognitive framed exposure perception is the main determinant of RF EMF risk perception. The concomitant sensitivity to exposure strength offers an opportunity to improve the acceptance of base stations by exposure reduction. A linear regression analysis supported this assumption: in a fictional test situation, exposure reduction improved the acceptance of base stations, operationalized as the requested distance of the base station from one's own home. Furthermore, subjects with high RF EMF risk perception were most sensitive to exposure reduction. On average, a 70% exposure reduction reduced the requested distance from about 2000 meters to 1000 meters. The consequences for risk communication are discussed. PMID:26229540

The influence of operator position, height and body orientation on eye lens dose in interventional radiology and cardiology: Monte Carlo simulations versus realistic clinical measurements.

PubMed

Principi, S; Farah, J; Ferrari, P; Carinou, E; Clairand, I; Ginjaume, M

2016-09-01

This paper aims to provide some practical recommendations to reduce eye lens dose for workers exposed to X-rays in interventional cardiology and radiology and also to propose an eye lens correction factor when lead glasses are used. Monte Carlo simulations are used to study the variation of eye lens exposure with operator position, height and body orientation with respect to the patient and the X-ray tube. The paper also looks into the efficiency of wraparound lead glasses using simulations. Computation results are compared with experimental measurements performed in Spanish hospitals using eye lens dosemeters as well as with data from available literature. Simulations showed that left eye exposure is generally higher than the right eye, when the operator stands on the right side of the patient. Operator height can induce a strong dose decrease by up to a factor of 2 for the left eye for 10-cm-taller operators. Body rotation of the operator away from the tube by 45°-60° reduces eye exposure by a factor of 2. The calculation-based correction factor of 0.3 for wraparound type lead glasses was found to agree reasonably well with experimental data. Simple precautions, such as the positioning of the image screen away from the X-ray source, lead to a significant reduction of the eye lens dose. Measurements and simulations performed in this work also show that a general eye lens correction factor of 0.5 can be used when lead glasses are worn regardless of operator position, height and body orientation. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

The moving-window Bayesian Maximum Entropy framework: Estimation of PM2.5 yearly average concentration across the contiguous United States

PubMed Central

Akita, Yasuyuki; Chen, Jiu-Chiuan; Serre, Marc L.

2013-01-01

Geostatistical methods are widely used in estimating long-term exposures for air pollution epidemiological studies, despite their limited capabilities to handle spatial non-stationarity over large geographic domains and uncertainty associated with missing monitoring data. We developed a moving-window (MW) Bayesian Maximum Entropy (BME) method and applied this framework to estimate fine particulate matter (PM2.5) yearly average concentrations over the contiguous U.S. The MW approach accounts for the spatial non-stationarity, while the BME method rigorously processes the uncertainty associated with data missingnees in the air monitoring system. In the cross-validation analyses conducted on a set of randomly selected complete PM2.5 data in 2003 and on simulated data with different degrees of missing data, we demonstrate that the MW approach alone leads to at least 17.8% reduction in mean square error (MSE) in estimating the yearly PM2.5. Moreover, the MWBME method further reduces the MSE by 8.4% to 43.7% with the proportion of incomplete data increased from 18.3% to 82.0%. The MWBME approach leads to significant reductions in estimation error and thus is recommended for epidemiological studies investigating the effect of long-term exposure to PM2.5 across large geographical domains with expected spatial non-stationarity. PMID:22739679

In utero exposure to dioxin causes neocortical dysgenesis through the actions of p27Kip1

PubMed Central

Mitsuhashi, Takayuki; Yonemoto, Junzo; Sone, Hideko; Kosuge, Yasuhiro; Kosaki, Kenjiro; Takahashi, Takao

2010-01-01

Dioxins have been reported to exert various adverse effects, including cell-cycle dysregulation in vitro and impairment of spatial learning and memory after in utero exposure in rodents. Furthermore, children born to mothers who are exposed to dioxin analogs polychlorinated dibenzofurans or polychlorinated biphenyls have developmental impairments in cognitive functions. Here, we show that in utero exposure to dioxins in mice alters differentiation patterns of neural progenitors and leads to decreased numbers of non-GABAergic neurons and thinner deep neocortical layers. This reduction in number of non-GABAergic neurons is assumed to be caused by accumulation of cyclin-dependent kinase inhibitor p27Kip1 in nuclei of neural progenitors. Lending support to this presumption, mice lacking p27Kip1 are not susceptible to in utero dioxin exposure. These results show that environmental pollutants may affect neocortical histogenesis through alterations of functions of specific gene(s)/protein(s) (in our case, dioxins), exerting adverse effects by altering functions of p27Kip1. PMID:20805476

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

PubMed

Zimmer, Alex M; Wood, Chris M

2014-01-01

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

Car free cities: Pathway to healthy urban living.

PubMed

Nieuwenhuijsen, Mark J; Khreis, Haneen

2016-09-01

Many cities across the world are beginning to shift their mobility solution away from the private cars and towards more environmentally friendly and citizen-focused means. Hamburg, Oslo, Helsinki, and Madrid have recently announced their plans to become (partly) private car free cities. Other cities like Paris, Milan, Chengdu, Masdar, Dublin, Brussels, Copenhagen, Bogota, and Hyderabad have measures that aim at reducing motorized traffic including implementing car free days, investing in cycling infrastructure and pedestrianization, restricting parking spaces and considerable increases in public transport provision. Such plans and measures are particularly implemented with the declared aim of reducing greenhouse gas emissions. These reductions are also likely to benefit public health. We aimed to describe the plans for private car free cities and its likely effects on public health. We reviewed the grey and scientific literature on plans for private car free cities, restricted car use, related exposures and health. An increasing number of cities are planning to become (partly) private car free. They mainly focus on the reduction of private car use in city centers. The likely effects of such policies are significant reductions in traffic-related air pollution, noise, and temperature in city centers. For example, up to a 40% reduction in NO2 levels has been reported on car free days. These reductions are likely to lead to a reduction in premature mortality and morbidity. Furthermore the reduction in the number of cars, and therefore a reduction in the need for parking places and road space, provides opportunities to increase green space and green networks in cities, which in turn can lead to many beneficial health effects. All these measures are likely to lead to higher levels of active mobility and physical activity which may improve public health the most and also provide more opportunities for people to interact with each other in public space. Furthermore, such initiatives, if undertaken at a sufficiently large scale can result in positive distal effects and climate change mitigation through CO2 reductions. The potential negative effects which may arise due to motorized traffic detouring around car free zone into their destinations also need further evaluation and the areas in which car free zones are introduced need to be given sufficient attention so as not to become an additional way to exacerbate socioeconomic divides. The extent and magnitude of all the above effects is still unclear and needs further research, including full chain health impact assessment modeling to quantify the potential health benefits of such schemes, and exposure and epidemiological studies to measure any changes when such interventions take place. The introduction of private car free cities is likely to have direct and indirect health benefits, but the exact magnitude and potential conflicting effects are as yet unclear. This paper has overviewed the expected health impacts, which can be useful to underpin policies to reduce car use in cities. Copyright © 2016 Elsevier Ltd. All rights reserved.

Transient induced tungsten melting at the Joint European Torus (JET)

NASA Astrophysics Data System (ADS)

Coenen, J. W.; Matthews, G. F.; Krieger, K.; Iglesias, D.; Bunting, P.; Corre, Y.; Silburn, S.; Balboa, I.; Bazylev, B.; Conway, N.; Coffey, I.; Dejarnac, R.; Gauthier, E.; Gaspar, J.; Jachmich, S.; Jepu, I.; Makepeace, C.; Scannell, R.; Stamp, M.; Petersson, P.; Pitts, R. A.; Wiesen, S.; Widdowson, A.; Heinola, K.; Baron-Wiechec, A.; Contributors, JET

2017-12-01

Melting is one of the major risks associated with tungsten (W) plasma-facing components (PFCs) in tokamaks like JET or ITER. These components are designed such that leading edges and hence excessive plasma heat loads deposited at near normal incidence are avoided. Due to the high stored energies in ITER discharges, shallow surface melting can occur under insufficiently mitigated plasma disruption and so-called edge localised modes—power load transients. A dedicated program was carried out at the JET to study the physics and consequences of W transient melting. Following initial exposures in 2013 (ILW-1) of a W-lamella with leading edge, new experiments have been performed on a sloped surface (15{}\\circ slope) during the 2015/2016 (ILW-3) campaign. This new experiment allows significantly improved infrared thermography measurements and thus resolved important issue of power loading in the context of the previous leading edge exposures. The new lamella was monitored by local diagnostics: spectroscopy, thermography and high-resolution photography in between discharges. No impact on the main plasma was observed despite a strong increase of the local W source consistent with evaporation. In contrast to the earlier exposure, no droplet emission was observed from the sloped surface. Topological modifications resulting from the melting are clearly visible between discharges on the photographic images. Melt damage can be clearly linked to the infrared measurements: the emissivity drops in zones where melting occurs. In comparison with the previous leading edge experiment, no runaway melt motion is observed, consistent with the hypothesis that the escape of thermionic electrons emitted from the melt zone is largely suppressed in this geometry, where the magnetic field intersects the surface at lower angles than in the case of perpendicular impact on a leading edge. Utilising both exposures allows us to further test the model of the forces driving melt motion that successfully reproduced the findings from the original leading edge exposure. Since the ILW-1 experiments, the exposed misaligned lamella has now been retrieved from the JET machine and post mortem analysis has been performed. No obvious mass loss is observed. Profilometry of the ILW-1 lamella shows the structure of the melt damage which is in line with the modell predictions thus allowing further model validation. Nuclear reaction analysis shows a tenfold reduction in surface deuterium concentration in the molten surface in comparison to the non-molten part of the lamella.

Residential energy use emissions dominate health impacts from exposure to ambient particulate matter in India.

PubMed

Conibear, Luke; Butt, Edward W; Knote, Christoph; Arnold, Stephen R; Spracklen, Dominick V

2018-02-12

Exposure to ambient fine particulate matter (PM 2.5 ) is a leading contributor to diseases in India. Previous studies analysing emission source attributions were restricted by coarse model resolution and limited PM 2.5 observations. We use a regional model informed by new observations to make the first high-resolution study of the sector-specific disease burden from ambient PM 2.5 exposure in India. Observed annual mean PM 2.5 concentrations exceed 100 μg m -3 and are well simulated by the model. We calculate that the emissions from residential energy use dominate (52%) population-weighted annual mean PM 2.5 concentrations, and are attributed to 511,000 (95UI: 340,000-697,000) premature mortalities annually. However, removing residential energy use emissions would avert only 256,000 (95UI: 162,000-340,000), due to the non-linear exposure-response relationship causing health effects to saturate at high PM 2.5 concentrations. Consequently, large reductions in emissions will be required to reduce the health burden from ambient PM 2.5 exposure in India.

Nursing research in community-based approaches to reduce exposure to secondhand smoke.

PubMed

Hahn, Ellen J; Ashford, Kristin B; Okoli, Chizimuzo T C; Rayens, Mary Kay; Ridner, S Lee; York, Nancy L

2009-01-01

Secondhand smoke (SHS) is the third leading cause of preventable death in the United States and a major source of indoor air pollution, accounting for an estimated 53,000 deaths per year among nonsmokers. Secondhand smoke exposure varies by gender, race/ethnicity, and socioeconomic status. The most effective public health intervention to reduce SHS exposure is to implement and enforce smoke-free workplace policies that protect entire populations including all workers regardless of occupation, race/ethnicity, gender, age, and socioeconomic status. This chapter summarizes community and population-based nursing research to reduce SHS exposure. Most of the nursing research in this area has been policy outcome studies, documenting improvement in indoor air quality, worker's health, public opinion, and reduction in Emergency Department visits for asthma, acute myocardial infarction among women, and adult smoking prevalence. These findings suggest a differential health effect by strength of law. Further, smoke-free laws do not harm business or employee turnover, nor are revenues from charitable gaming affected. Additionally, smoke-free laws may eventually have a positive effect on cessation among adults. There is emerging nursing science exploring the link between SHS exposure to nicotine and tobacco dependence, suggesting one reason that SHS reduction is a quit smoking strategy. Other nursing research studies address community readiness for smoke-free policy, and examine factors that build capacity for smoke-free policy. Emerging trends in the field include tobacco free health care and college campuses. A growing body of nursing research provides an excellent opportunity to conduct and participate in community and population-based research to reduce SHS exposure for both vulnerable populations and society at large.

Ground-based research with heavy ions for space radiation protection

NASA Astrophysics Data System (ADS)

Durante, M.; Kronenberg, A.

Human exposure to ionizing radiation is one of the acknowledged potential showstoppers for long duration manned interplanetary missions. Human exploratory missions cannot be safely performed without a substantial reduction of the uncertainties associated with different space radiation health risks, and the development of effective countermeasures. Most of our knowledge of the biological effects of heavy charged particles comes from accelerator-based experiments. During the 35th COSPAR meeting, recent ground-based experiments with high-energy iron ions were discussed, and these results are briefly summarised in this paper. High-quality accelerator-based research with heavy ions will continue to be the main source of knowledge of space radiation health effects and will lead to reductions of the uncertainties in predictions of human health risks. Efforts in materials science, nutrition and pharmaceutical sciences and their rigorous evaluation with biological model systems in ground-based accelerator experiments will lead to the development of safe and effective countermeasures to permit human exploration of the Solar System.

Fatigue responses of lead zirconate titanate stacks under semibipolar electric cycling with mechanical preload

NASA Astrophysics Data System (ADS)

Wang, Hong; Cooper, Thomas A.; Lin, Hua-Tay; Wereszczak, Andrew A.

2010-10-01

Lead zirconate titanate (PZT) stacks that had an interdigital internal electrode configuration were tested to more than 108 cycles. A 100 Hz semibipolar sine wave with a field range of +4.5/-0.9 kV/mm was used in cycling with a concurrently-applied 20 MPa preload. Significant reductions in piezoelectric and dielectric responses were observed during the cycling depending on the measuring condition. Extensive partial discharges were also observed. These surface events resulted in the erosion of external electrode and the exposure of internal electrodes. Sections prepared by sequential polishing technique revealed a variety of damage mechanisms including delaminations, pores, and etch grooves. The scale of damage was correlated with the degree of fatigue-induced reduction in piezoelectric and dielectric responses. The results from this study demonstrate the feasibility of using a semibipolar mode to drive a PZT stack under a mechanical preload and illustrate the potential fatigue and damages of the stack in service.

Primary prevention of lead poisoning in children: a cross-sectional study to evaluate state specific lead-based paint risk reduction laws in preventing lead poisoning in children.

PubMed

Kennedy, Chinaro; Lordo, Robert; Sucosky, Marissa Scalia; Boehm, Rona; Brown, Mary Jean

2014-11-07

Children younger than 72 months are most at risk of environmental exposure to lead from ingestion through normal mouthing behavior. Young children are more vulnerable to lead poisoning than adults because lead is absorbed more readily in a child's gastrointestinal tract. Our focus in this study was to determine the extent to which state mandated lead laws have helped decrease the number of new cases of elevated blood-lead levels (EBLL) in homes where an index case had been identified. A cross-sectional study was conducted to compare 682 residential addresses, identified between 2000 and 2009, in two states with and one state without laws to prevent childhood lead poisoning among children younger than 72 months, to determine whether the laws were effective in preventing subsequent cases of lead poisoning detected in residential addresses after the identification of an index case. In this study, childhood lead poisoning was defined as the blood lead level (BLL) that would have triggered an environmental investigation in the residence. The two states with lead laws, Massachusetts (MA) and Ohio (OH), had trigger levels of ≥25 μg/dL and ≥15 μg/dL respectively. In Mississippi (MS), the state without legislation, the trigger level was ≥15 μg/dL. The two states with lead laws, MA and OH, were 79% less likely than the one without legislation, MS, to have residential addresses with subsequent lead poisoning cases among children younger than 72 months, adjusted OR = 0.21, 95% CI (0.08-0.54). For the three states studied, the evidence suggests that lead laws such as those studied herein effectively reduced primary exposure to lead among young children living in residential addresses that may have had lead contaminants.

Regional Myelin and Axon Damage and Neuroinflammation in the Adult Mouse Brain After Long-Term Postnatal Vanadium Exposure.

PubMed

Azeez, Idris A; Olopade, Funmilayo; Laperchia, Claudia; Andrioli, Anna; Scambi, Ilaria; Onwuka, Silas K; Bentivoglio, Marina; Olopade, James O

2016-09-01

Environmental exposure to vanadium occurs in areas of persistent burning of fossil fuels; this metal is known to induce oxidative stress and oligodendrocyte damage. Here, we determined whether vanadium exposure (3 mg/kg) in mice during the first 3 postnatal months leads to a sustained neuroinflammatory response. Body weight monitoring, and muscle strength and open field tests showed reduction of body weight gain and locomotor impairment in vanadium-exposed mice. Myelin histochemistry and immunohistochemistry for astrocytes, microglia, and nonphosphorylated neurofilaments revealed striking regional heterogeneity. Myelin damage involved the midline corpus callosum and fibers in cortical gray matter, hippocampus, and diencephalon that were associated with axonal damage. Astrocyte and microglial activation was identified in the same regions and in the internal capsule; however, no overt myelin and axon damage was observed in the latter. Double immunofluorescence revealed induction of high tumor necrosis factor (TNF) immunoreactivity in reactive astrocytes. Western blotting analysis showed significant induction of TNF and interleukin-1β expression. Together these findings show that chronic postnatal vanadium exposure leads to functional deficit and region-dependent myelin damage that does not spare axons. This injury is associated with glial cell activation and proinflammatory cytokine induction, which may reflect both neurotoxic and neuroprotective responses. © 2016 American Association of Neuropathologists, Inc. All rights reserved.

Coupling contaminants with demography: Effects of lead and selenium in Pacific common eiders

USGS Publications Warehouse

Wilson, H.M.; Flint, Paul L.; Powell, A.N.

2007-01-01

We coupled intensive population monitoring with collection of blood samples from 383 nesting Pacific common eiders (Somateria mollisima v-nigrum) at two locations in Alaska (USA) from 2002 to 2004. We investigated annual, geographic, and within-season variation in blood concentrations of lead and selenium; compared exposure patterns with sympatrically nesting spectacled eiders (Somateria fischeri); and examined relationships with clutch size, egg viability, probability of hatching, and apparent survival of adult females. Lead concentrations were elevated in 3.6% of females, and all individuals exhibited elevated selenium, most (81%) at concentrations associated with death in captive waterfowl. Blood lead and selenium concentrations varied both within and among site-years and were lower than those of spectacled eiders. During incubation, blood lead concentrations in females increased significantly (possibly via re-release of stored lead from bone), whereas selenium concentrations decreased (likely because of natural excretion). Probability of a nest containing at least one nonviable egg was positively related to blood selenium in hens, but adverse effects in other life-history variables were not supported. Although reproduction appeared to be sensitive to selenium toxicity, our data suggest that high rates of nonviability are unlikely in this population and that selenium-related reductions to clutch size would be inconsequential at the scale of overall population dynamics. We conclude that Pacific common eiders and other wild marine birds likely have higher selenium tolerances than freshwater species and that interspecific differences in exposure levels may reflect differences in reproductive strategies.

Isocyanate exposure and asthma in the UK vehicle repair industry.

PubMed

Stocks, S J; Jones, K; Piney, M; Agius, R M

2015-12-01

Organic diisocyanates are a common cause of occupational asthma, particularly in motor vehicle repair (MVR) workers. The UK Health & Safety Laboratory provides screening for urinary hexamethylenediamine (UHDA), a biomarker of exposure to 1,6-hexamethylene diisocyanate (HDI). The UK Surveillance of Work-related and Occupational Respiratory Disease scheme (SWORD) has collected reports of occupational asthma since 1996. To compare trends in HDI exposure with trends in the incidence of work-related asthma attributed to isocyanates or paint spraying in MVR workers reported to SWORD. Two-level regression models were used to estimate trends in UHDA levels and work-related asthma in MVR workers reported to SWORD. The direction and magnitude of the trends were compared descriptively. From 2006 to 2014, there was a significant decline in the number of urine samples with detectable levels of UHDA (odds ratio = 0.96; 95% confidence intervals 0.94-0.98) and minimal change in those over the guidance value (1.03; 1.00-1.06). Over the same period, there was a significant decline in all asthma cases attributed to isocyanates or paint spraying reported to SWORD (0.90; 0.86-0.94) and a non-significant decline among MVR workers (0.94; 0.86-1.02). The simultaneous decrease in HDI exposure and incident cases of asthma reported to SWORD is temporally consistent with a reduction in exposure to airborne isocyanate leading to a reduction in asthma. Although this is not direct evidence of a causal relationship between the two trends, it is suggestive. © The Author 2015. Published by Oxford University Press on behalf of the Society of Occupational Medicine.

Isocyanate exposure and asthma in the UK vehicle repair industry

PubMed Central

Jones, K.; Piney, M.; Agius, R. M.

2015-01-01

Background Organic diisocyanates are a common cause of occupational asthma, particularly in motor vehicle repair (MVR) workers. The UK Health & Safety Laboratory provides screening for urinary hexamethylenediamine (UHDA), a biomarker of exposure to 1,6-hexamethylene diisocyanate (HDI). The UK Surveillance of Work-related and Occupational Respiratory Disease scheme (SWORD) has collected reports of occupational asthma since 1996. Aims To compare trends in HDI exposure with trends in the incidence of work-related asthma attributed to isocyanates or paint spraying in MVR workers reported to SWORD. Methods Two-level regression models were used to estimate trends in UHDA levels and work-related asthma in MVR workers reported to SWORD. The direction and magnitude of the trends were compared descriptively. Results From 2006 to 2014, there was a significant decline in the number of urine samples with detectable levels of UHDA (odds ratio = 0.96; 95% confidence intervals 0.94–0.98) and minimal change in those over the guidance value (1.03; 1.00–1.06). Over the same period, there was a significant decline in all asthma cases attributed to isocyanates or paint spraying reported to SWORD (0.90; 0.86–0.94) and a non-significant decline among MVR workers (0.94; 0.86–1.02). Conclusions The simultaneous decrease in HDI exposure and incident cases of asthma reported to SWORD is temporally consistent with a reduction in exposure to airborne isocyanate leading to a reduction in asthma. Although this is not direct evidence of a causal relationship between the two trends, it is suggestive. PMID:26209793

ALARA radiation considerations for the AP600 reactor

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

Lau, F.L.

1995-03-01

The radiation design of the AP600 reactor plant is based on an average annual occupational radiation exposure (ORE) of 100 man-rem. As a design goal we have established a lower value of 70 man-rem per year. And, with our current design process, we expect to achieve annual exposures which are well below this goal. To accomplish our goal we have established a process that provides criteria, guidelines and customer involvement to achieve the desired result. The criteria and guidelines provide the shield designer, as well as the systems and plant layout designers with information that will lead to an integratedmore » plant design that minimizes personnel exposure and yet is not burdened with complicated shielding or unnecessary component access limitations. Customer involvement is provided in the form of utility input, design reviews and information exchange. Cooperative programs with utilities in the development of specific systems or processes also provides for an ALARA design. The results are features which include ALARA radiation considerations as an integral part of the plant design and a lower plant ORE. It is anticipated that a further reduction in plant personnel exposures will result through good radiological practices by the plant operators. The information in place to support and direct the plant designers includes the Utility Requirements Document (URD), Federal Regulations, ALARA guidelines, radiation design information and radiation and shielding design criteria. This information, along with the utility input, design reviews and information feedback, will contribute to the reduction of plant radiation exposure levels such that they will be less than the stated goals.« less

Dietary exposure to the endocrine disruptor tolylfluanid promotes global metabolic dysfunction in male mice.

PubMed

Regnier, Shane M; Kirkley, Andrew G; Ye, Honggang; El-Hashani, Essam; Zhang, Xiaojie; Neel, Brian A; Kamau, Wakanene; Thomas, Celeste C; Williams, Ayanna K; Hayes, Emily T; Massad, Nicole L; Johnson, Daniel N; Huang, Lei; Zhang, Chunling; Sargis, Robert M

2015-03-01

Environmental endocrine disruptors are implicated as putative contributors to the burgeoning metabolic disease epidemic. Tolylfluanid (TF) is a commonly detected fungicide in Europe, and previous in vitro and ex vivo work has identified it as a potent endocrine disruptor with the capacity to promote adipocyte differentiation and induce adipocytic insulin resistance, effects likely resulting from activation of glucocorticoid receptor signaling. The present study extends these findings to an in vivo mouse model of dietary TF exposure. After 12 weeks of consumption of a normal chow diet supplemented with 100 parts per million TF, mice exhibited increased body weight gain and an increase in total fat mass, with a specific augmentation in visceral adipose depots. This increased adipose accumulation is proposed to occur through a reduction in lipolytic and fatty acid oxidation gene expression. Dietary TF exposure induced glucose intolerance, insulin resistance, and metabolic inflexibility, while also disrupting diurnal rhythms of energy expenditure and food consumption. Adipose tissue endocrine function was also impaired with a reduction in serum adiponectin levels. Moreover, adipocytes from TF-exposed mice exhibited reduced insulin sensitivity, an effect likely mediated through a specific down-regulation of insulin receptor substrate-1 expression, mirroring effects of ex vivo TF exposure. Finally, gene set enrichment analysis revealed an increase in adipose glucocorticoid receptor signaling with TF treatment. Taken together, these findings identify TF as a novel in vivo endocrine disruptor and obesogen in mice, with dietary exposure leading to alterations in energy homeostasis that recapitulate many features of the metabolic syndrome.

Virtual Embodiment of White People in a Black Virtual Body Leads to a Sustained Reduction in Their Implicit Racial Bias.

PubMed

Banakou, Domna; Hanumanthu, Parasuram D; Slater, Mel

2016-01-01

Virtual reality can be used to visually substitute a person's body by a life-sized virtual one. Such embodiment results in a perceptual illusion of body ownership over the virtual body (VB). Previous research has shown that the form of the VB can influence implicit attitudes. In particular, embodying White people in a Black virtual body is associated with an immediate decrease in their implicit racial bias against Black people. We tested whether the reduction in implicit bias lasts for at least 1 week and whether it is enhanced by multiple exposures. Two experiments were carried out with a total of 90 female participants where the virtual body was either Black or White. Participants were required to follow a virtual Tai Chi teacher who was either Asian or European Caucasian. Each participant had 1, 2, or 3 exposures separated by days. Implicit racial bias was measured 1 week before their first exposure and 1 week after their last. The results show that implicit bias decreased more for those with the Black virtual body than the White. There was also some evidence of a general decrease in bias independently of body type for which possible explanations are put forward.

Silver nanoparticles disrupt germline stem cell maintenance in the Drosophila testis

NASA Astrophysics Data System (ADS)

Ong, Cynthia; Lee, Qian Ying; Cai, Yu; Liu, Xiaoli; Ding, Jun; Yung, Lin-Yue Lanry; Bay, Boon-Huat; Baeg, Gyeong-Hun

2016-02-01

Silver nanoparticles (AgNPs), one of the most popular nanomaterials, are commonly used in consumer products and biomedical devices, despite their potential toxicity. Recently, AgNP exposure was reported to be associated with male reproductive toxicity in mammalian models. However, there is still a limited understanding of the effects of AgNPs on spermatogenesis. The fruit fly Drosophila testis is an excellent in vivo model to elucidate the mechanisms underlying AgNP-induced defects in spermatogenesis, as germ lineages can be easily identified and imaged. In this study, we evaluated AgNP-mediated toxicity on spermatogenesis by feeding Drosophila with AgNPs at various concentrations. We first observed a dose-dependent uptake of AgNPs in vivo. Concomitantly, AgNP exposure caused a significant decrease in the viability and delay in the development of Drosophila in a dose-dependent manner. Furthermore, AgNP-treated male flies showed a reduction in fecundity, and the resulting testes contained a decreased number of germline stem cells (GSCs) compared to controls. Interestingly, testes exposed to AgNPs exhibited a dramatic increase in reactive oxygen species levels and showed precocious GSC differentiation. Taken together, our study suggests that AgNP exposure may increase ROS levels in the Drosophila testis, leading to a reduction of GSC number by promoting premature GSC differentiation.

Virtual Embodiment of White People in a Black Virtual Body Leads to a Sustained Reduction in Their Implicit Racial Bias

PubMed Central

Banakou, Domna; Hanumanthu, Parasuram D.; Slater, Mel

2016-01-01

Virtual reality can be used to visually substitute a person's body by a life-sized virtual one. Such embodiment results in a perceptual illusion of body ownership over the virtual body (VB). Previous research has shown that the form of the VB can influence implicit attitudes. In particular, embodying White people in a Black virtual body is associated with an immediate decrease in their implicit racial bias against Black people. We tested whether the reduction in implicit bias lasts for at least 1 week and whether it is enhanced by multiple exposures. Two experiments were carried out with a total of 90 female participants where the virtual body was either Black or White. Participants were required to follow a virtual Tai Chi teacher who was either Asian or European Caucasian. Each participant had 1, 2, or 3 exposures separated by days. Implicit racial bias was measured 1 week before their first exposure and 1 week after their last. The results show that implicit bias decreased more for those with the Black virtual body than the White. There was also some evidence of a general decrease in bias independently of body type for which possible explanations are put forward. PMID:27965555

Silver nanoparticle-induced cytotoxicity in rat brain endothelial cell culture.

PubMed

Grosse, Susann; Evje, Lars; Syversen, Tore

2013-02-01

Silver nanoparticles (AgNPs) are among the most widely commercialised engineered nanomaterials, because of their antimicrobial properties. They are already commonly used in medical devices, household products and industry. Concerns have been raised about potential adverse health effects due to increasing dispersion of AgNPs in the environment. The present study examined the cytotoxic effects of spherical, citrate-coated AgNPs (10, 50 and 100 nm) in rat brain endothelial (RBE4) cells and investigated whether the observed effects can be explained by the intrinsic toxicity of the particles or the silver ions released from the particles. The results indicated that exposure of RBE4 cells to AgNPs lead to significant reduction in dye uptake as measured with the Neutral red (NR) assay. The effect was found to be related to particle size, surface area, dose and exposure time. In contrast, silver ions increased NR uptake (ca. 10%) in RBE4 cells after 1h, while a reduction in NR uptake was observed after 24h exposure at high concentrations (20-30 μM). Colony formation, as an indicator of proliferation ability, was completely inhibited by AgNPs at concentrations higher than 1 μg/ml. Silver ions had less effect on the colony formation of RBE4 cells than AgNPs. Copyright © 2012 Elsevier Ltd. All rights reserved.

Gut Dysbiosis and Neurobehavioral Alterations in Rats Exposed to Silver Nanoparticles.

PubMed

Javurek, Angela B; Suresh, Dhananjay; Spollen, William G; Hart, Marcia L; Hansen, Sarah A; Ellersieck, Mark R; Bivens, Nathan J; Givan, Scott A; Upendran, Anandhi; Kannan, Raghuraman; Rosenfeld, Cheryl S

2017-06-06

Due to their antimicrobial properties, silver nanoparticles (AgNPs) are being used in non-edible and edible consumer products. It is not clear though if exposure to these chemicals can exert toxic effects on the host and gut microbiome. Conflicting studies have been reported on whether AgNPs result in gut dysbiosis and other changes within the host. We sought to examine whether exposure of Sprague-Dawley male rats for two weeks to different shapes of AgNPs, cube (AgNC) and sphere (AgNS) affects gut microbiota, select behaviors, and induces histopathological changes in the gastrointestinal system and brain. In the elevated plus maze (EPM), AgNS-exposed rats showed greater number of entries into closed arms and center compared to controls and those exposed to AgNC. AgNS and AgNC treated groups had select reductions in gut microbiota relative to controls. Clostridium spp., Bacteroides uniformis, Christensenellaceae, and Coprococcus eutactus were decreased in AgNC exposed group, whereas, Oscillospira spp., Dehalobacterium spp., Peptococcaeceae, Corynebacterium spp., Aggregatibacter pneumotropica were reduced in AgNS exposed group. Bacterial reductions correlated with select behavioral changes measured in the EPM. No significant histopathological changes were evident in the gastrointestinal system or brain. Findings suggest short-term exposure to AgNS or AgNC can lead to behavioral and gut microbiome changes.

The Impact of Iodide-Mediated Ozone Deposition and ...

EPA Pesticide Factsheets

The air quality of many large coastal areas in the United States is affected by the confluence of polluted urban and relatively clean marine airmasses, each with distinct atmospheric chemistry. In this context, the role of iodide-mediated ozone (O3) deposition over seawater and marine halogen chemistry accounted for in both the lateral boundary conditions and coastal waters surrounding the continental U.S. is examined using the Community Multiscale Air Quality (CMAQ) model. Several nested simulations are conducted in which these halogen processes are implemented separately in the continental U.S. and hemispheric CMAQ domains, the latter providing lateral boundary conditions for the former. Overall, it is the combination of these processes within both the continental U.S. domain and from lateral boundary conditions that lead to the largest reductions in modeled surface O3 concentrations. Predicted reductions in surface O3 concentrations occur mainly along the coast where CMAQ typically has large overpredictions. These results suggest that a realistic representation of halogen processes in marine regions can improve model prediction of O3 concentrations near the coast. The National Exposure Research Laboratory (NERL) Computational Exposure Division (CED) develops and evaluates data, decision-support tools, and models to be applied to media-specific or receptor-specific problem areas. CED uses modeling-based approaches to characterize exposures, evaluate fate and

Feather lead concentrations and (207)Pb/(206)Pb ratios reveal lead exposure history of California Condors (Gymnogyps californianus).

PubMed

Finkelstein, M E; George, D; Scherbinski, S; Gwiazda, R; Johnson, M; Burnett, J; Brandt, J; Lawrey, S; Pessier, A P; Clark, M; Wynne, J; Grantham, J; Smith, D R

2010-04-01

Lead poisoning is a primary factor impeding the survival and recovery of the critically endangered California Condor (Gymnogyps californianus). However, the frequency and magnitude of lead exposure in condors is not well-known in part because most blood lead monitoring occurs biannually, and biannual blood samples capture only approximately 10% of a bird's annual exposure history. We investigated the use of growing feathers from free-flying condors in California to establish a bird's lead exposure history. We show that lead concentration and stable lead isotopic composition analyses of sequential feather sections and concurrently collected blood samples provided a comprehensive history of lead exposure over the 2-4 month period of feather growth. Feather analyses identified exposure events not evident from blood monitoring efforts, and by fitting an empirically derived timeline to actively growing feathers, we were able to estimate the time frame for specific lead exposure events. Our results demonstrate the utility of using sequentially sampled feathers to reconstruct lead exposure history. Since exposure risk in individuals is one determinant of population health, our findings should increase the understanding of population-level effects from lead poisoning in condors; this information may also be helpful for other avian species potentially impacted by lead poisoning.

Feather lead concentrations and 207Pb/206Pb ratios reveal lead exposure history of California Condors (Gymnogyps californianus)

USGS Publications Warehouse

Finkelstein, M.E.; George, D.; Scherbinski, S.; Gwiazda, R.; Johnson, M.; Burnett, J.; Brandt, J.; Lawrey, S.; Pessier, Allan P.; Clark, M.R.; Wynne, J.; Grantham, And J.; Smith, D.R.

2010-01-01

Lead poisoning is a primary factor impeding the survival and recovery of the critically endangered California Condor (Gymnogyps californianus). However, the frequency and magnitude of lead exposure in condors is not well-known in part because most blood lead monitoring occurs biannually, and biannual blood samples capture only ∼10% of a bird’s annual exposure history. We investigated the use of growing feathers from free-flying condors in California to establish a bird’s lead exposure history. We show that lead concentration and stable lead isotopic composition analyses of sequential feather sections and concurrently collected blood samples provided a comprehensive history of lead exposure over the 2−4 month period of feather growth. Feather analyses identified exposure events not evident from blood monitoring efforts, and by fitting an empirically derived timeline to actively growing feathers, we were able to estimate the time frame for specific lead exposure events. Our results demonstrate the utility of using sequentially sampled feathers to reconstruct lead exposure history. Since exposure risk in individuals is one determinant of population health, our findings should increase the understanding of population-level effects from lead poisoning in condors; this information may also be helpful for other avian species potentially impacted by lead poisoning.

Personnel dose reduction in 90Y microspheres liver-directed radioembolization: from interventional radiology suite to patient ward

PubMed Central

Wong, K K; Tso, W K; Lee, Victor; Luk, M Y; Tong, C C; Chu, Ferdinand

2017-01-01

Objective: To describe a method to reduce the external radiation exposure emitted from the patient after liver-directed radioembolization using 90Y glass microspheres, to quantitatively estimate the occupational dose of medical personnel providing patient care to the patient radioembolized with the use of the method and to discuss radiation exposure to patients who are adjacent if the patient radioembolized needs hospitalization. Methods: A lead-lined blanket of lead equivalence of 0.5 mm was used to cover the patient abdomen immediately after the 90Y radioembolization procedure, in order to reduce the radiation emitted from the patient. The interventional radiologist used a rod-type puncture site compressor for haemostasis to avoid direct contact with possible residual radioactivity at the puncture site. Dose rates were measured at the interventional radiologist chest and hand positions during puncture site pressing for haemostasis with and without the use of the blanket. The measurement results were applied to estimate the occupational dose of colleagues performing patient care to the patient radioembolized. The exposure to patients adjacent in the ward was estimated if the patient radioembolized was hospitalized. Results: The radiation exposures measured at the radiologist chest and hand positions have been significantly reduced with the lead-lined blanket in place. The radiologist, performing puncture site pressing at the end of radioembolization procedure, would receive an average hand dose of 1.95 μSv and body dose under his own lead apron of 0.30 μSv for an average 90Y microsphere radioactivity of 2.54 GBq. Other medical personnel, nurses and porters, would receive occupational doses corresponding to an hour of background radiation. If the patient radioembolized using 90Y needs hospitalization in a common ward, using the lead-lined blanket to cover the abdomen of the patient and keeping a distance of 2 m from the patient who is adjacent would reduce the exposure by 0.42% of dose limit for the general public. Conclusion: By placing a lead-lined blanket on the patient abdominal region after 90Y radioembolization, hospital staff receive minimal radiation exposure in order to comply with the radiation protection “as low as reasonably achievable” principle. There will be no increase in radiation level in ward if the patient radioembolized using 90Y needs to be hospitalized. Therefore, the patient radioembolized can be accommodated alternatively at a corner bed of a common ward if an isolation room with private toilet facility is not available. Advances in knowledge: To reduce exposure to personnel providing patient care to patients radioembolized using 90Y. PMID:27993095

Open reduction and internal fixation of intra-articular fractures of the mandibular condyle: our first experiences.

PubMed

Vesnaver, Ales

2008-10-01

Treatment of intra-articular fractures of the mandibular condyle head is conservative at most institutions dealing with facial fractures. Recently, reports had been published about benefits of surgical treatment in these fractures. From July 2004 until the end of June 2006, 13 patients with 16 displaced intra-articular fractures of the mandibular condyle were treated with open reduction and internal fixation at the Department of Oral and Maxillofacial Surgery in Ljubljana, Slovenia, using the preauricular approach and the lag screw technique. Twelve of the 13 patients could open their mouths for 40 mm or more, and 10 had a deflection of the chin of less than 2 mm upon maximal opening. None of the patients experienced pain upon rest, palpation, or chewing. Occlusion was not noted as altered in any of the cases, neither subjectively, nor on examination. There were no cases of postoperative weakness of the temporal branch of the facial nerve. Surgical treatment of intra-articular condyle fractures using the preauricular approach achieves a good exposure and enables proper reduction. Stable fixation of fractured bony fragments can be achieved using the lag screw technique. Another benefit of open exposure is revision and repair of TMJ soft tissues. With the appropriate surgical technique, the surgical procedure is safe and leads to good results.

Protective effects of ascorbic acid and garlic extract against lead-induced apoptosis in developing rat hippocampus.

PubMed

Ebrahimzadeh-Bideskan, Ali-Reza; Hami, Javad; Alipour, Fatemeh; Haghir, Hossein; Fazel, Ali-Reza; Sadeghi, Akram

2016-10-01

Lead exposure has negative effects on developing nervous system and induces apoptosis in newly generated neurons. Natural antioxidants (i.e. Ascorbic acid and Garlic) might protect against lead-induced neuronal cell damage. The aim of the present study was to investigate the protective effects of Ascorbic acid and Garlic administration during pregnancy and lactation on lead-induced apoptosis in rat developing hippocampus. Timed pregnant Wistar rats were administrated with Lead (1500 ppm) via drinking water (Pb group) or lead plus Ascorbic acid (Pb + AA Group, 500 mg/kg, IP), or lead plus Garlic Extract (Pb + G Group, 1 ml garlic juice/100 g BW, via Gavage) from early gestation (GD 0) until postnatal day 50 (PN 50). At the end of experiments, the pups' brains were carefully dissected. To identify neuronal death, the brain sections were stained with TUNEL assay. Mean of blood and brain lead levels increased significantly in Pb group comparing to other studied groups (P < 0.01). There was significant reduction in blood and brain lead level in Pb + AA and Pb + G groups when compared to those of Pb group (P < 0.01). The mean number of TUNEL positive cells in the CA1, CA3, and DG was significantly lower in the groups treated by either Ascorbic acid or Garlic (P < 0.05). Administration of Ascorbic acid and Garlic during pregnancy and lactation protect against lead-induced neuronal cell apoptosis in the hippocampus of rat pups partially via the reduction of Pb concentration in the blood and in the brain.

Standard pentostatin dose reductions in renal insufficiency are not adequate: selected patients with steroid-refractory acute graft-versus-host disease.

PubMed

Poi, Ming J; Hofmeister, Craig C; Johnston, Jeffrey S; Edwards, Ryan B; Jansak, Buffy S; Lucas, David M; Farag, Sherif S; Dalton, James T; Devine, Steven M; Grever, Michael R; Phelps, Mitch A

2013-08-01

Pentostatin is an irreversible inhibitor of adenosine deaminase and has been used to prevent graft-versus-host disease (GVHD) and to treat both acute and chronic GVHD. Dose reduction equations for patients with renal insufficiency are based on few patients with limited pharmacokinetic and clinical results. This phase II study (NCT00201786) was conducted to assess pentostatin efficacy and infectious complications seen from our previous phase I study in steroid-refractory acute GVHD (aGVHD). Hospitalized patients with steroid-refractory aGVHD were given pentostatin 1.5 mg/m(2)/day intravenously on days 1-3 of each 14-day cycle. Prior to each dose, dose modifications were based on Cockcroft-Gault estimated creatinine clearance (eCrCL) with 30-50 mL/min/1.73 m(2) leading to a 50 % dose reduction and eCrCL less than 30 mL/min/1.73 m(2) leading to study removal. Plasma pentostatin area under the concentration-time curve (AUC) and incidence of infectious complications were evaluated. Two of the eight patients treated demonstrated excessive pentostatin exposure as determined by measurement of AUC. One of these patients had renal impairment, whereas the other patient demonstrated borderline renal function. Despite dose reduction to 0.75 mg/m(2), AUCs were significantly increased compared to the other patients in this study. Seven of eight patients treated with pentostatin had cytomegalovirus (CMV) viremia after pentostatin treatment; however none developed proven CMV disease. A 50 % dose reduction in patients with eCrCL 30-50 mL/min/1.73 m(2) seems reasonable. However, the eCrCL should be interpreted with extreme caution in patients who are critically ill and/or with poor performance status. Renal function assessment based on the Cockcroft-Gault method could be significantly overestimated thus risking pentostatin overdosing. These results imply a need to closely monitor pentostatin exposure in patients with renal insufficiency.

Standard Pentostatin Dose Reductions in Renal Insufficiency are not Adequate: Selected Patients with Steroid-Refractory Acute Graft-versus-Host Disease

PubMed Central

Poi, Ming J.; Hofmeister, Craig C.; Johnston, Jeffrey S.; Edwards, Ryan B.; Jansak, Buffy S.; Lucas, David M.; Farag, Sherif S.; Dalton, James T.; Devine, Steven M.; Grever, Michael R.; Phelps, Mitch A.

2013-01-01

Background and Objective Pentostatin is an irreversible inhibitor of adenosine deaminase and has been used to prevent graft-versus-host disease (GVHD) and to treat both acute and chronic GVHD. Dose reduction equations for patients with renal insufficiency are based on few patients with limited pharmacokinetic and clinical results. This phase II study (NCT00201786) was conducted to assess pentostatin efficacy and infectious complications seen from our previous phase I study in steroid-refractory acute GVHD (aGVHD). Patients and Methods Hospitalized patients with steroid-refractory aGVHD were given pentostatin 1.5 mg/m2/day intravenously on days 1–3 of each 14 day cycle. Prior to each dose, dose modifications were based on Cockcroft-Gault estimated creatinine clearance (eCrCL) with 30–50 ml/min/1.73m2 leading to a 50% dose reduction and eCrCL< 30 ml/min/1.73m2 leading to study removal. Plasma pentostatin area under the concentration-time curve (AUC) and incidence of infectious complications were evaluated. Results Two of the eight patients treated demonstrated excessive pentostatin exposure as determined by measurement of AUC. One of these patients had renal impairment while the other patient demonstrated borderline renal function. Despite dose reduction to 0.75 mg/m2, AUCs were significantly increased compared to the other patients in this study. Seven of eight patients treated with pentostatin had cytomegalovirus (CMV) viremia after pentostatin treatment; however none developed proven CMV disease. Conclusion A 50% dose reduction in patients with eCrCL 30–50 ml/min/1.73m2 seems reasonable. However, the eCrCL should be interpreted with extreme cautions in patients who are critically ill and/or with poor performance status. Renal function assessment based on the Cockcroft-Gault method could be significantly overestimated thus risking pentostatin over-dosing. These results imply a need to closely monitor pentostatin exposure in patients with renal insufficiency. PMID:23588536

Soil Lead and Children’s Blood Lead Disparities in Pre- and Post-Hurricane Katrina New Orleans (USA)

PubMed Central

Mielke, Howard W.; Gonzales, Christopher R.; Powell, Eric T.

2017-01-01

This study appraises New Orleans soil lead and children’s lead exposure before and ten years after Hurricane Katrina flooded the city. Introduction: Early childhood exposure to lead is associated with lifelong and multiple health, learning, and behavioral disorders. Lead exposure is an important factor hindering the long-term resilience and sustainability of communities. Lead exposure disproportionately affects low socioeconomic status of communities. No safe lead exposure is known and the common intervention is not effective. An essential responsibility of health practitioners is to develop an effective primary intervention. Methods: Pre- and post-Hurricane soil lead and children’s blood lead data were matched by census tract communities. Soil lead and blood lead data were described, mapped, blood lead graphed as a function of soil lead, and Multi-Response Permutation Procedures statistics established disparities. Results: Simultaneous decreases occurred in soil lead accompanied by an especially large decline in children’s blood lead 10 years after Hurricane Katrina. Exposure disparities still exist between children living in the interior and outer areas of the city. Conclusions: At the scale of a city, this study demonstrates that decreasing soil lead effectively reduces children’s blood lead. Primary prevention of lead exposure can be accomplished by reducing soil lead in the urban environment. PMID:28417939

Soil Lead and Children's Blood Lead Disparities in Pre- and Post-Hurricane Katrina New Orleans (USA).

PubMed

Mielke, Howard W; Gonzales, Christopher R; Powell, Eric T

2017-04-12

This study appraises New Orleans soil lead and children's lead exposure before and ten years after Hurricane Katrina flooded the city. Introduction : Early childhood exposure to lead is associated with lifelong and multiple health, learning, and behavioral disorders. Lead exposure is an important factor hindering the long-term resilience and sustainability of communities. Lead exposure disproportionately affects low socioeconomic status of communities. No safe lead exposure is known and the common intervention is not effective. An essential responsibility of health practitioners is to develop an effective primary intervention. Methods : Pre- and post-Hurricane soil lead and children's blood lead data were matched by census tract communities. Soil lead and blood lead data were described, mapped, blood lead graphed as a function of soil lead, and Multi-Response Permutation Procedures statistics established disparities. Results : Simultaneous decreases occurred in soil lead accompanied by an especially large decline in children's blood lead 10 years after Hurricane Katrina. Exposure disparities still exist between children living in the interior and outer areas of the city. Conclusions : At the scale of a city, this study demonstrates that decreasing soil lead effectively reduces children's blood lead. Primary prevention of lead exposure can be accomplished by reducing soil lead in the urban environment.

Reasons for testing and exposure sources among women of childbearing age with moderate blood lead levels.

PubMed

Fletcher, A M; Gelberg, K H; Marshall, E G

1999-06-01

The purpose of this study was to examine the circumstances under which women receive blood lead tests in New York State and to characterize the sources of lead exposure among women of childbearing age with moderate blood lead levels. Telephone interviews were conducted with 135 women between the ages of 18 and 45, with blood lead levels from 10 through 25 micrograms/dl, were used to collect information on the reason for their blood lead test and possible sources of lead exposure. It was found that the two most common reasons to be tested for blood lead were workplace screening (47%) and pregnancy (27%). Occupational exposure was the primary source of lead exposure in this population (46%). Another common source of lead exposure was home renovation (24%). A significant proportion (31%) of women with blood lead levels from 10 through 25 micrograms/dl had no known current source of lead exposure. Based on New York's sample, there are a significant number of women of reproductive age with potentially fetotoxic blood lead levels.

Determinants of blood-lead levels in children in Callao and Lima metropolitan area.

PubMed

Espinoza, Rocío; Hernández-Avila, Mauricio; Narciso, Juan; Castañaga, Carmen; Moscoso, Shirley; Ortiz, Georgina; Carbajal, Luz; Wegner, Steve; Noonan, Gary

2003-01-01

To determine blood lead levels in urban populations of children (n = 2,510) and women (n = 874) in the early postpartum in certain districts of Lima and Callao, and to correlate those levels with particular exposures. Between July 1998 and January 1999 cross sectional study was conducted. The study population was selected using three sampling strategies in the government operated school system and from public pediatric and maternity hospitals at Lima and Callao, Peru. Study personnel were trained to collect finger stick blood samples with a protocol that minimizes external lead contamination. Lead determinations in blood and environmental samples were performed at the study site using portable anodic striping voltamenters. To determine the simultaneous effects of different predictors on blood lead levels, multivariate regression models were used to estimate adjusted mean differences. The mean blood lead level in the children studied was 9.9 micrograms/dl ranging from 1 microgram/dl to 64 micrograms/dl with 29% of the children displaying values greater than 10 micrograms/dl and 9.4% at levels greater than 20 micrograms/dl. Among the women, the mean was 3.5 micrograms/dl (SD = 2.4 micrograms/dl), and 2.4% (n = 21) displayed levels greater than 10 micrograms/dl. Important differences were observed between the sample locations, and the highest levels were documented in the port region near Callao. The mean level of blood lead in this group was 25.6 micrograms/dl (SD = 4.6 micrograms/dl), while among the rest of the sample it was 7.1 micrograms/dl (SD = 5.1 micrograms/dl). The presence of a mineral storage area signified a difference in exposure in excess of 13 micrograms/dl for children living near the port area in contrast to the other children who were not as close to such fixed sources of lead exposure. For the participants in Lima, the risk of showing levels above 10 micrograms/dl was associated with exposure to high vehicular traffic. In metropolitan Lima, we conclude that the mean blood lead levels of the populations studied were not alarming and that a positive health impact can be made by a reduction of lead in gasoline. With regard to the port area, the study demonstrates that the presence of mineral storage areas pose a detrimental risk factor for the health of the children living in this area. The English version of this paper is available too at: http://www.insp.mx/salud/index.html.

Unraveling the Reactivity of Minium toward Bicarbonate and the Role of Lead Oxides Therein.

PubMed

Ayalew, Eyasu; Janssens, Koen; De Wael, Karolien

2016-02-02

Understanding the reactivity of (semiconductor) pigments provides vital information on how to improve conservation strategies for works of art to avoid rapid degradation of the pigments. This study focuses on the photoactivity of minium (Pb3O4), a semiconductor pigment that gives rise to strong discoloration phenomena upon exposure to various environmental conditions. For demonstrating its photoactivity, an electrochemical setup with a minium-modified graphite electrode (C|Pb3O4) was used. It is confirmed that minium is a p-type semiconductor that is photoactive during illumination and becomes inactive in the dark. Raman measurements confirm the formation of degradation products. The photoactivity of a semiconductor pigment is partly defined by the presence of lead oxide (PbO) impurities; these introduce new states in the original band gap. It will be experimentally evidenced that the presence of PbO particles in minium leads to an upward shift of the valence band that reduces the band gap. Thus, upon photoexcitation, the electron/hole separation is more easily initialized. The PbO/Pb3O4 composite electrodes demonstrate a higher reductive photocurrent compared to the photocurrent registered at pure PbO or Pb3O4-modified electrodes. Upon exposure to light with energy close to and above the band gap, electrons are excited from the valence band to the conduction band to initialize the reduction of Pb(IV) to Pb(II), resulting in the initial formation of PbO. However, in the presence of bicarbonate ions, a significantly higher photoreduction current is recorded because the PbO reacts further to form hydrocerussite. Therefore, the presence of bicarbonates in the environment stimulates the photodecomposition process of minium and plays an important role in the degradation process.

Acyl guanidine inhibitors of β-secretase (BACE-1): optimization of a micromolar hit to a nanomolar lead via iterative solid- and solution-phase library synthesis.

PubMed

Gerritz, Samuel W; Zhai, Weixu; Shi, Shuhao; Zhu, Shirong; Toyn, Jeremy H; Meredith, Jere E; Iben, Lawrence G; Burton, Catherine R; Albright, Charles F; Good, Andrew C; Tebben, Andrew J; Muckelbauer, Jodi K; Camac, Daniel M; Metzler, William; Cook, Lynda S; Padmanabha, Ramesh; Lentz, Kimberley A; Sofia, Michael J; Poss, Michael A; Macor, John E; Thompson, Lorin A

2012-11-08

This report describes the discovery and optimization of a BACE-1 inhibitor series containing an unusual acyl guanidine chemotype that was originally synthesized as part of a 6041-membered solid-phase library. The synthesis of multiple follow-up solid- and solution-phase libraries facilitated the optimization of the original micromolar hit into a single-digit nanomolar BACE-1 inhibitor in both radioligand binding and cell-based functional assay formats. The X-ray structure of representative inhibitors bound to BACE-1 revealed a number of key ligand:protein interactions, including a hydrogen bond between the side chain amide of flap residue Gln73 and the acyl guanidine carbonyl group, and a cation-π interaction between Arg235 and the isothiazole 4-methoxyphenyl substituent. Following subcutaneous administration in rats, an acyl guanidine inhibitor with single-digit nanomolar activity in cells afforded good plasma exposures and a dose-dependent reduction in plasma Aβ levels, but poor brain exposure was observed (likely due to Pgp-mediated efflux), and significant reductions in brain Aβ levels were not obtained.

Lead exposures in the human environment. Final report

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

Elias, R.W.

Humans consume lead by inhaling air, drinking beverages, eating food and ingesting dust. The natural source of this lead is primarily soil. Anthropogenic sources are lead in gasoline, fossil fuels and industrial products and processes. Lead is ubiquitous in the human environment, and pinpointing the primary sources of lead in any particular environmental component is difficult. Nevertheless, our purpose is to describe the total exposure of humans to environmental lead and to determine the sources of lead contributing to this exposure. The total exposure is the total amount of lead consumed by ingestion and inhalation. Excluding lead exposure from choicemore » or circumstance, a baseline level of potential human exposure can be defined for a normal individual eating a typical diet and living in a non-urban community remote from industrial sources of lead in a house without lead-based paints. Beyond this level, additive exposure factors can be determined for other environments (e.g. urban, occupational and smelter communities) and for certain habits and activities (e.g. pica, smoking, drinking and hobbies), with variation for age, sex or socioeconomic status.« less

Historical View on Lead: Guidelines and Regulations.

PubMed

Pohl, Hana R; Ingber, Susan Z; Abadin, Henry G

2017-04-10

Lead has been used in many commodities for centuries. As a result, human exposure has occurred through the production and use of these lead-containing products. For example, leaded gasoline, lead-based paint, and lead solder/pipes in water distribution systems have been important in terms of exposure potential to the general population. Worker exposures occur in various industrial activities such as lead smelting and refining, battery manufacturing, steel welding or cutting operations, printing, and construction. Some industrial locations have also been a source of exposure to the surrounding communities. While the toxicity of relatively high lead exposures has been recognized for centuries, modern scientific studies have shown adverse health effects at very low doses, particularly in the developing nervous system of fetuses and children. This chapter reflects on historical and current views on lead toxicity. It also addresses the development and evolution of exposure prevention policies. As discussed here, these lead policies target a variety of potential exposure routes and sources. The changes reflect our better understanding of lead toxicity. The chapter provides lead-related guidelines and regulations currently valid in the U. S. and in many countries around the world. The reader will learn about the significant progress that has been made through regulations and guidelines to reduce exposure and prevent lead toxicity.

Anaerobiosis Induced State Transition: A Non Photochemical Reduction of PQ Pool Mediated by NDH in Arabidopsis thaliana

PubMed Central

Tirupathi, Malavath; Subramanyam, Rajagopal

2012-01-01

Background Non photochemical reduction of PQ pool and mobilization of LHCII between PSII and PSI are found to be linked under abiotic stress conditions. The interaction of non photochemical reduction of PQ pool and state transitions associated physiological changes are critically important under anaerobic condition in higher plants. Methodology/Findings The present study focused on the effect of anaerobiosis on non-photochemical reduction of PQ pool which trigger state II transition in Arabidopsis thaliana. Upon exposure to dark-anaerobic condition the shape of the OJIP transient rise is completely altered where as in aerobic treated leaves the rise is unaltered. Rise in F o and F J was due to the loss of oxidized PQ pool as the PQ pool becomes more reduced. The increase in Fo′ was due to the non photochemical reduction of PQ pool which activated STN7 kinase and induced LHCII phosphorylation under anaerobic condition. Further, it was observed that the phosphorylated LHCII is migrated and associated with PSI supercomplex increasing its absorption cross-section. Furthermore, evidences from crr2-2 (NDH mutant) and pgr5 mutants (deficient in non NDH pathway of cyclic electron transport) have indicated that NDH is responsible for non photochemical reduction of the PQ pool. We propose that dark anaerobic condition accelerates production of reducing equivalents (such as NADPH by various metabolic pathways) which reduce PQ pool and is mediated by NDH leading to state II transition. Conclusions/Significance Anaerobic condition triggers non photochemical reduction of PQ pool mediated by NDH complex. The reduced PQ pool activates STN7 kinase leading to state II transition in A. thaliana. PMID:23185453

Retrospective evaluation of lead contamination in honey from 2005 to present in northeastern Italy and future perspectives in the light of updated legislation.

PubMed

Martinello, Marianna; Dainese, Nicoletta; Manzinello, Chiara; Borin, Alice; Gallina, Albino; Mutinelli, Franco

2016-09-01

Lead is a naturally occurring element but largely originating from human activities. Food is the major source of exposure to lead for humans and the publication of a scientific opinion from the European Food Safety Authority on the risks to human health related to the presence of lead in foodstuffs, led European Union to establish more restrictive limits for this contaminant in food from 1 January 2016. In particular, a maximum level of 0.10 mg kg(-1) was established for honey. The retrospective evaluation of 995 honey samples analysed since 2005, revealed a progressive reduction in the concentration of lead, with a mean value of 0.045 mg kg(-1) in 2015. Total 1.5% of honeys analysed in 2015 exceeded the maximum lead level and therefore will no longer be marketable. Interested beekeepers should clarify the causes of honey contamination and adopt corrective actions to keep their honey production within the legal levels of lead.

Lead exposure is a risk for worsening bone mineral density in middle-aged male workers.

PubMed

Akbal, Ayla; Tutkun, Engin; Yılmaz, Hınç

2014-09-01

Lead exposure linked to osteoporosis in women. However, there is no direct evidence whether lead exposure has effects on bone metabolism in middle-aged male subjects. Therefore, the present study investigated the relationship between bone mineral densitometry measurements, bone markers, endocrine hormones and blood lead levels. The present study included lead exposure patients (n: 30) and control subjects (n: 32). We recorded information on patient demographics and risk factors of osteoporosis. Blood lead levels were evaluated using Varian AA 240Z atomic absorption spectrophotometry. Bone mineral density measurements were measured using dual-energy X-ray absorptiometry. Each lumbar T and Z scores in the lead exposure group were lower than the control group. There were no significant differences in femur neck and femur total T and Z scores between two groups. Blood lead levels were also negatively correlated with lumbar 2-4 T score, total lumbar T score, lumbar 2-4 Z score and total lumbar Z score. Urinary hydroxyproline and urinary deoxypyridinoline levels in the lead exposure group were significantly higher compared to controls. Blood lead levels were strong, positively correlated with urinary deoxypyridinoline. Endocrine hormone levels and 1,25-dihydroxy-vitamin D3 levels were comparable between lead exposure and control group. Lead exposure in male workers is an important factor for deterioration in bone mineral density. We should be screening blood lead levels and history of lead exposure in male osteoporosis.

Chemical exposures in the workplace: effect on breast cancer risk among women.

PubMed

Snedeker, Suzanne M

2006-06-01

Occupational health nurses need to be aware of the current science on breast cancer risks in the workplace because they are risk communicators for employees and their families. Occupational health nurses can serve as advocates for necessary research ultimately leading to risk reduction and prevention strategies in the workplace. Current research suggests exposure to organic solvents, metals, acid mists, sterilizing agents (ethylene oxide), some pesticides, light at night (shift work), and tobacco smoke increases breast cancer risk among women in occupational settings. Animal cancer bioassays conducted by the National Toxicology Program indicate more than 40 chemicals can induce mammary tumors, and most of these are still in production. A variety of occupations worldwide, including health care providers and metal, textile, dye, rubber, and plastic manufacturing workers, have been identified as having some evidence of higher breast cancer risk. Although some chemical exposures are suspected to affect breast cancer risk, estimates of or actual exposures to these chemicals in the workplace often have not been determined. Research needed to better identify breast cancer risks in occupational settings includes monitoring breast cancer incidence in occupations with exposures to suspected carcinogens, characterizing chemical exposures by job type and task, determining whether potential gender differences affect chemical exposures, and using molecular approaches to identify gene-environment interactions.

CaNa2EDTA chelation attenuates cell damage in workers exposed to lead--a pilot study.

PubMed

Čabarkapa, A; Borozan, S; Živković, L; Stojanović, S; Milanović-Čabarkapa, M; Bajić, V; Spremo-Potparević, B

2015-12-05

Lead induced oxidative cellular damage and long-term persistence of associated adverse effects increases risk of late-onset diseases. CaNa2EDTA chelation is known to remove contaminating metals and to reduce free radical production. The objective was to investigate the impact of chelation therapy on modulation of lead induced cellular damage, restoration of altered enzyme activities and lipid homeostasis in peripheral blood of workers exposed to lead, by comparing the selected biomarkers obtained prior and after five-day CaNa2EDTA chelation intervention. The group of smelting factory workers diagnosed with lead intoxication and current lead exposure 5.8 ± 1.2 years were administered five-day CaNa2EDTA chelation. Elevated baseline activity of antioxidant enzymes Cu, Zn-SOD and CAT as well as depleted thiols and increased protein degradation products-carbonyl groups and nitrites, pointing to Pb induced oxidative damage, were restored toward normal values following the treatment. Lead showed inhibitor potency on both RBC AChE and BChE in exposed workers, and chelation re-established the activity of BChE, while RBC AChE remained unaffected. Also, genotoxic effect of lead detected in peripheral blood lymphocytes was significantly decreased after therapy, exhibiting 18.9% DNA damage reduction. Administration of chelation reversed the depressed activity of serum PON 1 and significantly decreased lipid peroxidation detected by the post-chelation reduction of MDA levels. Lactate dehydrogenase LDH1-5 isoenzymes levels showed evident but no significant trend of restoring toward normal control values following chelation. CaNa2EDTA chelation ameliorates the alterations linked with Pb mediated oxidative stress, indicating possible benefits in reducing health risks associated with increased oxidative damage in lead exposed populations. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Cross-sectional analysis of the possible relationship between lead exposure in the storage-battery industry and changes in biochemical markers of renal, hematopoietic, and hepatic functioning and the reporting of recent abdominal pain

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

Zelenak, J.P.

There is extensive literature documenting the physical effects, such as renal impairment and disruption of hematopoiesis, of lead exposure in occupational cohorts. In addition, a small number of case studies have suggested that lead exposure might result in hepatocellular effects. This study was undertaken to determine if these effects still existed for a population of lead storage battery workers exposed to occupational lead exposures which were lower than those experienced by most lead workers prior to 1978. The relationship between the lead exposure indices,zinc protoporphyrin (ZPP) and a time weighted average blood lead measure (TWA), with twelve biochemical parameters indicativemore » of renal, hematopoietic and hepatic functioning and the reporting of recent abdominal pain was investigated. In addition, the possible modifying effects of alcohol consumption and duration of exposure on the relationship between lead exposure and the biochemical parameters were examined. The subjects for this analysis consisted of 288 lead workers form three lead storage battery plants and a group of 181 workers employed in an industry which did not involve lead exposure. The study was conducted from 1982-83. Comparisons of the lead exposure indices with the dependent variables were made through univariate correlational and hierarchical regression analyses. The lead exposure index, ZPP, was significantly associated wit BUN levels, though less than three percent of the lead and control workers had BUN levels above the normal range, In addition, NPP, was negatively associated with hemoglobin levels at probability levels between 0.052 and 0.055. Furthermore, there were no hemoglobin levels outside of the normal range for any of the sites studied. The other lead exposure index, TWA, was significantly associated with alkaline phosphatase and triglycerides. However, these analyses were not age-adjusted.« less

Early light reduction for preventing retinopathy of prematurity in very low birth weight infants.

PubMed

Jorge, Eliane C; Jorge, Edson N; El Dib, Regina P

2013-08-06

Retinopathy of prematurity (ROP) is a complex condition of the developing retinal blood vessels and is one of the leading causes of preventable childhood blindness. Several risk factors for ROP have been studied over the past 50 years. Among them, general immaturity (low birth weight and low gestational age) and prolonged oxygen therapy have been consistently related to disease onset. However, it is understood that the progression of the disease is multifactorial and may be associated with others risk factors, such as multiple gestation, apnoea, intracranial haemorrhage, anaemia, sepsis, prolonged mechanical ventilation, multiple transfusions and light exposure. Furthermore, the precise role of these individual factors in the development of the disease has not yet been well established. To determine whether the reduction of early environmental light exposure reduces the incidence of retinopathy of prematurity (ROP) or poor ROP outcomes among very low birth weight infants. We searched the following databases: the Cochrane Neonatal Group Specialised Register, CENTRAL (The Cochrane Library), MEDLINE, EMBASE, CINAHL, HealthSTAR, Science Citation Index Database, CANCERLIT, the Oxford Database of Perinatal Trials and www.clinicaltrials.gov. We also searched previous reviews including cross-references, abstracts, conference and symposia proceedings, and contacted expert informants. This search was updated in October 2012. Randomised or quasi-randomised controlled trials that reduced light exposure to premature infants within the first seven days following birth were considered for this review. We also considered cluster-randomised controlled trials. Data on clinical outcomes including any acute ROP and poor ROP outcome were extracted by both review authors independently and consensus reached. We conducted data analysis according to the standards of the Cochrane Neonatal Review Group. Data from four randomised trials with a total of 897 participants failed to show any reduction in acute ROP or poor ROP outcome with the reduction of ambient light to premature infants' retinas. The overall methodological quality of the included studies was about evenly split between those in which the classification was unclear and those in which the studies were categorised as low risk of bias. There was no report on the secondary outcomes considered in this review: quality of life measures; and time of exposure to oxygen. The evidence shows that bright light is not the cause of retinopathy of prematurity and that the reduction of exposure of the retinas of premature infants to light has no effect on the incidence of the disease.

Radiation exposure of the radiologist's eye lens during CT-guided interventions.

PubMed

Heusch, Philipp; Kröpil, Patric; Buchbender, Christian; Aissa, Joel; Lanzman, Rotem S; Heusner, Till A; Ewen, Klaus; Antoch, Gerald; Fürst, Günther

2014-02-01

In the past decade the number of computed tomography (CT)-guided procedures performed by interventional radiologists have increased, leading to a significantly higher radiation exposure of the interventionalist's eye lens. Because of growing concern that there is a stochastic effect for the development of lens opacification, eye lens dose reduction for operators and patients should be of maximal interest. To determine the interventionalist's equivalent eye lens dose during CT-guided interventions and to relate the results to the maximum of the recommended equivalent dose limit. During 89 CT-guided interventions (e.g. biopsies, drainage procedures, etc.) measurements of eye lens' radiation doses were obtained from a dedicated dosimeter system for scattered radiation. The sensor of the personal dosimeter system was clipped onto the side of the lead glasses which was located nearest to the CT gantry. After the procedure, radiation dose (µSv), dose rate (µSv/min) and the total exposure time (s) were recorded. For all 89 interventions, the median total exposure lens dose was 3.3 µSv (range, 0.03-218.9 µSv) for a median exposure time of 26.2 s (range, 1.1-94.0 s). The median dose rate was 13.9 µSv/min (range, 1.1-335.5 µSv/min). Estimating 50-200 CT-guided interventions per year performed by one interventionalist, the median dose of the eye lens of the interventional radiologist does not exceed the maximum of the ICRP-recommended equivalent eye lens dose limit of 20 mSv per year.

Lead intoxication due to ayurvedic medications as a cause of abdominal pain in adults.

PubMed

Mehta, Varun; Midha, Vandana; Mahajan, Ramit; Narang, Vikram; Wander, Praneet; Sood, Ridhi; Sood, Ajit

2017-02-01

Though a majority of cases of lead intoxication come from occupational exposures, traditional and folk remedies have also been reported to contain toxic amounts of lead. We present a large series of patients with lead poisoning due to intake of Ayurvedic medicines, all of whom presented with unexplained abdominal pain. This was a retrospective, observational case series from a tertiary care center in India. The charts of patients who underwent blood lead level (BLL) testing as a part of workup for unexplained abdominal pain between 2005 and 2013 were reviewed. The patients with lead intoxication (BLLs >25 μg/dl) were identified and demographics, history, possible risk factors, clinical presentation and investigations were reviewed. Treatment details, duration, time to symptomatic recovery, laboratory follow-up and adverse events during therapy were recorded. BLLs were tested in 786 patients with unexplained abdominal pain and high levels were identified in 75 (9.5%) patients, of which a majority (73 patients, 9.3%) had history of Ayurvedic medication intake and only two had occupational exposure. Five randomly chosen Ayurvedic medications were analyzed and lead levels were impermissibly high (14-34,950 ppm) in all of them. Besides pain in abdomen, other presenting complaints were constipation, hypertension, neurological symptoms and acute kidney injury. Anemia and abnormal liver biochemical tests were observed in all the 73 patients. Discontinuing the Ayurvedic medicines and chelation with d-penicillamine led to improvement in symptoms and reduction in BLLs in all patients within 3-4 months. The patients presenting with severe recurrent abdominal pain, anemia and history of use of Ayurvedic medicines should be evaluated for lead toxicity. Early diagnosis in such cases can prevent unnecessary investigations and interventions, and permits early commencement of the treatment.

Monitoring and reducing exposure of infants to pollutants in house dust.

PubMed

Roberts, John W; Wallace, Lance A; Camann, David E; Dickey, Philip; Gilbert, Steven G; Lewis, Robert G; Takaro, Tim K

2009-01-01

The health risks to babies from pollutants in house dust may be 100 times greater than for adults. The young ingest more dust and are up to ten times more vulnerable to such exposures. House dust is the main exposure source for infants to allergens, lead, and PBDEs, as well as a major source of exposure to pesticides, PAHs, Gram-negative bacteria, arsenic, cadmium, chromium, phthalates, phenols, and other EDCs, mutagens, and carcinogens. Median or upper percentile concentrations in house dust of lead and several pesticides and PAHs may exceed health-based standards in North America. Early contact with pollutants among the very young is associated with higher rates of chronic illness such as asthma, loss of intelligence, ADHD, and cancer in children and adults. The potential of infants, who live in areas with soil contaminated by automotive and industrial emissions, can be given more protection by improved home cleaning and hand washing. Babies who live in houses built before 1978 have a prospective need for protection against lead exposures; homes built before 1940 have even higher lead exposure risks. The concentration of pollutants in house dust may be 2-32 times higher than that found in the soil near a house. Reducing infant exposures, at this critical time in their development, may reduce lifetime health costs, improve early learning, and increase adult productivity. Some interventions show a very rapid payback. Two large studies provide evidence that home visits to reduce the exposure of children with poorly controlled asthma triggers may return more than 100% on investment in 1 yr in reduced health costs. The tools provided to families during home visits, designed to reduce dust exposures, included vacuum cleaners with dirt finders and HEPA filtration, allergy control bedding covers, high-quality door mats, and HEPA air filters. Infants receive their highest exposure to pollutants in dust at home, where they spend the most time, and where the family has the most mitigation control. Normal vacuum cleaning allows deep dust to build up in carpets where it can be brought to the surface and become airborne as a result of activity on the carpet. Vacuums with dirt finders allow families to use the three-spot test to monitor deep dust, which can reinforce good cleaning habits. Motivated families that receive home visits from trained outreach workers can monitor and reduce dust exposures by 90% or more in 1 wk. The cost of such visits is low considering the reduction of risks achieved. Improved home cleaning is one of the first results observed among families who receive home visits from MHEs and CHWs. We believe that proven intervention methods can reduce the exposure of infants to pollutants in house dust, while recognizing that much remains to be learned about improving the effectiveness of such methods.

Trends in tobacco smoke exposure and blood lead levels among youths and adults in the United States: the National Health and Nutrition Examination Survey, 1999-2008.

PubMed

Richter, Patricia A; Bishop, Ellen E; Wang, Jiantong; Kaufmann, Rachel

2013-12-19

Tobacco smoke is a source of exposure to thousands of toxic chemicals including lead, a chemical of longstanding public health concern. We assessed trends in blood lead levels in youths and adults with cotinine-verified tobacco smoke exposure by using 10 years of data from the National Health and Nutrition Examination Survey. Geometric mean levels of blood lead are presented for increasing levels of tobacco smoke exposure. Regression models for lead included age, race/ethnicity, poverty, survey year, sex, age of home, birth country, and, for adults, alcohol consumption. Lead levels were evaluated for smokers and nonsmokers on the basis of age of residence and occupation. Positive trend tests indicate that a linear relationship exists between smoke exposure and blood lead levels in youths and adults and that secondhand smoke exposure contributes to blood lead levels above the level caused by smoking. Youths with secondhand smoke exposure had blood lead levels suggestive of the potential for adverse cognitive outcomes. Despite remediation efforts in housing and the environment and declining smoking rates and secondhand smoke exposure in the United States, tobacco smoke continues to be a substantial source of exposure to lead in vulnerable populations and the population in general.

[Application of the data from China Total Diet Study to assess the distribution of lead exposure in different age-gender population groups].

PubMed

Li, Xiaowei; Liu, Qing; Liu, Liping; Wu, Yongning

2012-05-01

To assess the distribution of dietary lead exposure in different age-gender groups of Chinese residents by using the data from China Total Diet Study, and combining the new risk assessment and the PTWI withdrawn by JECFA. Methods Combining the lead concentrations of dietary samples with the food consumption data from China Total Diet Study in 2007 to obtain the distribution of dietary intake and dietary source of lead in different age-gender population groups. Dietary lead exposure of different age-gender population groups in China was in the range of 48.7 -116.7 microg/d. The status of higher lead exposure in younger age groups was not optimistic, as the mean and median margins of exposure (MOE) have been less than 1.0 (0.1 - 0.3). The main sources of dietary lead were cereals and vegetables, which covering 57% of total lead exposure. Lowering the dietary lead exposure of Chinese residents is necessary, especially of infants and children.

Long-term human exposure to lead from different media and intake pathways.

PubMed

Pizzol, Massimo; Thomsen, Marianne; Andersen, Mikael Skou

2010-10-15

Lead (Pb) is well known as an environmental pollutant: it can accumulate in various media, so actual lead exposure reflects both historical and present contaminations. Two main challenges then emerge: obtaining updated information to gain an overall picture of the sources of exposure, and predicting the resulting internal body exposure levels and effects that occur under long-term exposure conditions. In this paper, a modeling approach is used to meet these challenges with reference to Danish exposure conditions. Levels of lead content in various media have been coupled with data for lead intake and absorption in the human body, for both children and adults. An age-dependent biokinetic model allows then for determination of the blood lead levels resulting from chronic exposure. The study shows that the actual intake of lead is up to 27% of the Provisional Tolerable Daily Intake (PTDI) for children and around 8% for adults. It is confirmed that the critical route of exposure is via ingestion, accounting for 99% of total lead intake, while inhalation contributes only to 1% of total lead intake. The resulting lead levels in the blood after 2 years of exposure to actual contamination conditions have been estimated as up to 2.2μg/dl in children and almost 1μg/dl in adults. Impacts from lead can occur even at such levels. The role of historical and present sources to lead in the environment is discussed, and, for specific child and adult exposure scenarios, external-internal concentration relationships for the direct linkage between lead in environmental media and resulting concentrations of lead in blood are then presented. Copyright © 2010 Elsevier B.V. All rights reserved.

Lead exposure potentiates predatory attack behavior in the cat.

PubMed

Li, Wenjie; Han, Shenggao; Gregg, Thomas R; Kemp, Francis W; Davidow, Amy L; Louria, Donald B; Siegel, Allan; Bogden, John D

2003-07-01

Epidemiologic studies have demonstrated that environmental lead exposure is associated with aggressive behavior in children; however, numerous confounding variables limit the ability of these studies to establish a causal relationship. The study of aggressive behavior using a validated animal model was used to test the hypothesis that there is a causal relationship between lead exposure and aggression in the absence of confounding variables. We studied the effects of lead exposure on a feline model of aggression: predatory (quiet biting) attack of an anesthetized rat. Five cats were stimulated with a precisely controlled electrical current via electrodes inserted into the lateral hypothalamus. The response measure was the predatory attack threshold current (i.e., the current required to elicit an attack response on 50% of the trials). Blocks of trials were administered in which predatory attack threshold currents were measured three times a week for a total of 6-10 weeks, including before, during, and after lead exposure. Lead was incorporated into cat food "treats" at doses of 50-150 mg/kg/day. Two of the five cats received a second period of lead exposure. Blood lead concentrations were measured twice a week and were <1, 21-77, and <20 micro g/dL prior to, during, and after lead exposure, respectively. The predatory attack threshold decreased significantly during initial lead exposure in three of five cats and increased after the cessation of lead exposure in four of the five cats (P<0.01). The predatory attack thresholds and blood lead concentrations for each cat were inversely correlated (r=-0.35 to -0.74). A random-effects mixed model demonstrated a significant (P=0.0019) negative association between threshold current and blood lead concentration. The data of this study demonstrate that lead exposure enhances predatory aggression in the cat and provide experimental support for a causal relationship between lead exposure and aggressive behavior in humans.

Chronic lead exposure reduces doublecortin-expressing immature neurons in young adult guinea pig cerebral cortex.

PubMed

Huang, JuFang; Huang, Kai; Shang, Lei; Wang, Hui; Zhang, Mengqi; Fan, Chun-Ling; Chen, Dan; Yan, Xiaoxin; Xiong, Kun

2012-07-19

Chronic lead (Pb) poisoning remains an environmental risk especially for the pediatric population, and it may affect brain development. Immature neurons expressing doublecortin (DCX+) exist around cortical layer II in various mammals, including adult guinea pigs and humans. Using young adult guinea pigs as an experimental model, the present study explored if chronic Pb exposure affects cortical DCX + immature neurons and those around the subventricular and subgranular zones (SVZ, SGZ). Two month-old guinea pigs were treated with 0.2% lead acetate in drinking water for 2, 4 and 6 months. Blood Pb levels in these animals reached 10.27 ± 0.62, 16.25 ± 0.78 and 19.03 ± 0.86 μg/dL at the above time points, respectively, relative to ~3 μg/dL in vehicle controls. The density of DCX + neurons was significantly reduced around cortical layer II, SVZ and SGZ in Pb-treated animals surviving 4 and 6 months relative to controls. Bromodeoxyuridine (BrdU) pulse-chasing studies failed to find cellular colocalization of this DNA synthesis indicator in DCX + cells around layer II in Pb-treated and control animals. These cortical immature neurons were not found to coexist with active caspase-3 or Fluoro-Jade C labeling. Chronic Pb exposure can lead to significant reduction in the number of the immature neurons around cortical layer II and in the conventional neurogenic sites in young adult guinea pigs. No direct evidence could be identified to link the reduced cortical DCX expression with alteration in local neurogenesis or neuronal death.

Prenatal lead exposure and bone growth. Doctoral thesis

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

Hamilton, J.D.; O'Flaherty, E.J.

1990-07-24

An experimental system of lead (7439921) related prenatal and postnatal growth retardation in rats was developed. Sprague-Dawley-rats and Long-Evans-rats were used in these studies. Rats were exposed to lead in their drinking water at up to 1000 parts per million. A significant effect on fetal bone mineralization could not be excluded and there was a definite effect on fetal body weight following maternal lead exposure. Reduced food intake during the first week of lead exposure was the primary determinant of reduced body and skeletal growth in the lead exposed weanling female rats. When maternal lead exposure was continued during lactationmore » a greater degree of lead related growth retardation in rat offspring occurred than when maternal lead exposure was terminated at parturition. Combined prenatal and postnatal lead exposure impaired bone resorption and increased growth plate widths. In studies using matrix induced endochondral bone plaques, locally applied lead enhanced plaque mineralization through comineralization of lead with calcium. When lead was administered in drinking water, plaque mineralization was also enhanced through the comineralization of lead with calcium.« less

Lead contamination in Uruguay: the "La Teja" neighborhood case.

PubMed

Mañay, Nelly; Cousillas, Adriana Z; Alvarez, Cristina; Heller, Teresa

2008-01-01

Lead, ubiquitous in the environment as a result of mining and industrialization, is found as a contaminant in humans although it has no known physiological function there. Lead-exposed children are known to be the population with the highest potential health risks. The recommended biomarker to assess environmental lead exposure in animals is lead level in blood. Before 2001, the Department of Toxicology and Environmental Hygiene was the only team to produce human monitoring data on Uruguayan populations (Manay 2001a,b; Mañay et al. 1999). Lead pollution in Uruguay first received official attention during the 2001 La Teja poisoning episode. It was in the La Teja neighbourhood of Montevideo that high BLL were found in children (as high as 20 microg/dL), prompting corrective responses from Health and Environmental authorities. Growing awareness of environmental lead pollution and consequential human health effects from that event, resulted in public debate and demands for solutions from Health and Environmental authorities. Citizens demanded public disclosure of information concerning lead pollution and wanted action to address contaminated Uruguayan sites. In response, the Ministry of Health assembled an interinstitutional multidisciplinary committee, with delegates from health, environmental, labor, educational, and social security authorities, as well as community nongovernmental organizations (NGOs), among others. The University of the Republic was designated to serve as the main responsible entity for technical advice and support. After 2001, new research on lead pollution was undertaken and included multidisciplinary studies with communities in response to health risk alerts. The main emphasis was placed on children exposed to environmental lead. Major sources of Uruguayan lead contamination, similar to those in other developing countries, result from metallurgical industries, lead-acid battery processing, lead wire and pipe factories, metal foundries, metal recyclers, leaded gasoline (before December 2003), lead water pipes in old houses, and scrap and smelter solid wastes, among others. Nonoccupational lead exposure usually results from living in or near current or former manufacturing areas or improper handling of lead-containing materials or solid wastes (a particularly important health risk for children). In this chapter, we reviewed available studies published or reported after the pollution events first announced in 2001. These studies include data on exposure, health, and actions taken to mitigate or prevent lead exposure from pollution events in Uruguay. Uruguay adopted CDC's 10 microg/dL as the reference BLL for children (CDC 1991) and a BLL of 30 microg/dL for workers (from the ACGIH standard). Environmental authorities adopted the Canadian reference concentrations for soil: residential and playgrounds (> 140 mg/kg) or industrial areas (> 600 mg/kg) (CCME 2006). Most studies reviewed addressed soil pollution as the main source of lead exposure. Results of thousands of analyses indicated that most children had BLL above reference intervention limits. A significant decrease in BLL was also found over time in the study results, demonstrating the importance of medical intervention, nutrition, and environmental education. The severity of lead pollution discovered required official governmental actions, both to reduce sources of lead contamination and to address the health implications for children who had been exposed to environmental or industrial lead pollution. Dogs were discovered to be useful sentinels for environmental lead pollution; they had higher BLL than children when exposed to the same polluted environment and developed symptoms of lead intoxication earlier and at lower BLL than did children. This same pattern was also observed in families with children and pet dogs living in the La Teja neighborhood. This discovery renders dogs prospectively useful in lead pollution monitoring and diagnosis, particularly in developing countries. BLL results from similar human lead exposure studies conducted 10 yr apart showed significant BLL reductions, after 10 yr, for nonoccupationally exposed Uruguayans. The phase-out of leaded gasoline is thought to have contributed to this improvement. New laws to address occupational and environmental exposures were passed to prevent new cases of lead contamination, and new research studies are underway to monitor lead pollution. Moreover, a systematic surveillance screening program for lead workers and children is planned, although it is not yet underway. The sensitization of the public to the lead pollution problem has been a key driver of governmental action to mitigate and prevent further lead pollution in Uruguay. The changes made since 2001 appear to have yielded positive results. BLL from different populations studied more recently show decreased lead levels, suggesting a lower contribution of environmental lead to exposure of children and nonoccupationally exposed adults. The diverse analytical data collected on lead pollution in Uruguay between 2001 and 2004 were the main ingredient that allowed effective identification of lead pollution in Uruguay and paved the way for official intervention to prevent new pollution events. Nevertheless, full research studies must still be done, including both spot analysis of environmental soil, air, and water samples, and extensive screening of BLL. Future health and environmental actions are needed, not only to remediate known areas of lead pollution, but also to investigate other sources of potential health risks.

Mapping the spatio-temporal risk of lead exposure in apex species for more effective mitigation

PubMed Central

Mateo-Tomás, Patricia; Olea, Pedro P.; Jiménez-Moreno, María; Camarero, Pablo R.; Sánchez-Barbudo, Inés S.; Rodríguez Martín-Doimeadios, Rosa C.; Mateo, Rafael

2016-01-01

Effective mitigation of the risks posed by environmental contaminants for ecosystem integrity and human health requires knowing their sources and spatio-temporal distribution. We analysed the exposure to lead (Pb) in griffon vulture Gyps fulvus—an apex species valuable as biomonitoring sentinel. We determined vultures' lead exposure and its main sources by combining isotope signatures and modelling analyses of 691 bird blood samples collected over 5 years. We made yearlong spatially explicit predictions of the species risk of lead exposure. Our results highlight elevated lead exposure of griffon vultures (i.e. 44.9% of the studied population, approximately 15% of the European, showed lead blood levels more than 200 ng ml−1) partly owing to environmental lead (e.g. geological sources). These exposures to environmental lead of geological sources increased in those vultures exposed to point sources (e.g. lead-based ammunition). These spatial models and pollutant risk maps are powerful tools that identify areas of wildlife exposure to potentially harmful sources of lead that could affect ecosystem and human health. PMID:27466455

Recommendations for Medical Management of Adult Lead Exposure

PubMed Central

Kosnett, Michael J.; Wedeen, Richard P.; Rothenberg, Stephen J.; Hipkins, Karen L.; Materna, Barbara L.; Schwartz, Brian S.; Hu, Howard; Woolf, Alan

2007-01-01

Research conducted in recent years has increased public health concern about the toxicity of lead at low dose and has supported a reappraisal of the levels of lead exposure that may be safely tolerated in the workplace. In this article, which appears as part of a mini-monograph on adult lead exposure, we summarize a body of published literature that establishes the potential for hypertension, effects on renal function, cognitive dysfunction, and adverse female reproductive outcome in adults with whole-blood lead concentrations < 40 μg/dL. Based on this literature, and our collective experience in evaluating lead-exposed adults, we recommend that individuals be removed from occupational lead exposure if a single blood lead concentration exceeds 30 μg/dL or if two successive blood lead concentrations measured over a 4-week interval are ≥ 20 μg/dL. Removal of individuals from lead exposure should be considered to avoid long-term risk to health if exposure control measures over an extended period do not decrease blood lead concentrations to < 10 μg/dL or if selected medical conditions exist that would increase the risk of continued exposure. Recommended medical surveillance for all lead-exposed workers should include quarterly blood lead measurements for individuals with blood lead concentrations between 10 and 19 μg/dL, and semiannual blood lead measurements when sustained blood lead concentrations are < 10 μg/dL. It is advisable for pregnant women to avoid occupational or avocational lead exposure that would result in blood lead concentrations > 5 μg/dL. Chelation may have an adjunctive role in the medical management of highly exposed adults with symptomatic lead intoxication but is not recommended for asymptomatic individuals with low blood lead concentrations. PMID:17431500

Children's exposure to passive smoking in England since the 1980s: cotinine evidence from population surveys

PubMed Central

Jarvis, Martin J; Goddard, Eileen; Higgins, Vanessa; Feyerabend, Colin; Bryant, Andrew; Cook, Derek G

2000-01-01

Objective To determine whether children's exposure to passive smoking has changed since the late 1980s. Design Cross sectional surveys of nationally representative samples of secondary school children carried out between 1988 and 1998 by Office for National Statistics. Setting England. Subjects Secondary school children aged 11-15. Main outcome measures Salivary cotinine concentrations in non-smoking children. Results Cotinine concentrations in all non-smoking children almost halved between 1988 and 1998, from a geometric mean of 0.96 (95% confidence interval 0.83 to 1.11) ng/ml in 1988 to 0.52 (0.43 to 0.62) ng/ml in 1998. This reduction was largely due to reductions in exposure in children from non-smoking households and to decreases in the percentage of parents who smoked. Children living with mothers or fathers who smoked experienced little reduction in exposure. Conclusions Exposure to passive smoking among children in England has approximately halved since the late 1980s. This reduction is partly explained by the fall in the percentage of both mothers and fathers who smoke and is also likely to reflect reductions of smoking in public places. However, there is only limited evidence that children from smoking households have experienced a reduction in exposure through parents' avoidance of smoking in their presence. PMID:10926591

Spirulina exhibits hepatoprotective effects against lead induced oxidative injury in newborn rats.

PubMed

Gargouri, M; Ben Saad, H; Ben Amara, I; Magné, C; El Feki, A

2016-08-31

Lead is a toxic metal that induces a wide range of biochemical and physiological effects. The present investigation was designed at evaluating the toxic effects of a prenatal exposure to lead of mothers on hepatic tissue of newborn rats, and potent protective effects of spirulina. Female rats were randomly divided into 4 groups which were given a normal diet (control),a diet enriched with spirulina (S), lead acetate administered through drinking water (Pb), or a diet enriched with spirulina and lead contaminated water (S Pb), respectively. The duration of treatments was from the 5th day of gestation to 14 days postpartum. Lead toxicity was assessed by measuring body and liver weights, blood and stomach lead levels, hepatic DNA, RNA and protein amounts, blood enzyme activities (AST and ALT), as well as lipid peroxidation level and activities of antioxidant enzymes in hepatic tissues of neonates. Lead intoxication of mothers caused reduction of liver weight as well as of hepatic DNA, mRNA and protein levels in newborns. Moreover, oxidative stress and changes in antioxidant enzyme activities were recorded. Conversely, supplementation of mothers with spirulina mitigated these effects induced by lead. These results substantiated the potential hepatoprotective and antioxidant activity of spirulina.

Impact of robotics and a suspended lead suit on physician radiation exposure during percutaneous coronary intervention.

PubMed

Madder, Ryan D; VanOosterhout, Stacie; Mulder, Abbey; Elmore, Matthew; Campbell, Jessica; Borgman, Andrew; Parker, Jessica; Wohns, David

Reports of left-sided brain malignancies among interventional cardiologists have heightened concerns regarding physician radiation exposure. This study evaluated the impact of a suspended lead suit and robotic system on physician radiation exposure during percutaneous coronary intervention (PCI). Real-time radiation exposure data were prospectively collected from dosimeters worn by operating physicians at the head- and chest-level during consecutive PCI cases. Exposures were compared in three study groups: 1) manual PCI performed with traditional lead apparel; 2) manual PCI performed using suspended lead; and 3) robotic PCI performed in combination with suspended lead. Among 336 cases (86.6% manual, 13.4% robotic) performed over 30weeks, use of suspended lead during manual PCI was associated with significantly less radiation exposure to the chest and head of operating physicians than traditional lead apparel (chest: 0.0 [0.1] μSv vs 0.4 [4.0] μSv, p<0.001; head: 0.5 [1.9] μSv vs 14.9 [51.5] μSv, p<0.001). Chest-level radiation exposure during robotic PCI performed in combination with suspended lead was 0.0 [0.0] μSv, which was significantly less chest exposure than manual PCI performed with traditional lead (p<0.001) or suspended lead (p=0.046). In robotic PCI the median head-level exposure was 0.1 [0.2] μSv, which was 99.3% less than manual PCI performed with traditional lead (p<0.001) and 80.0% less than manual PCI performed with suspended lead (p<0.001). Utilization of suspended lead and robotics were observed to result in significantly less radiation exposure to the chest and head of operating physicians during PCI. Copyright © 2016 Elsevier Inc. All rights reserved.

High altitude induced anorexia: effect of changes in leptin and oxidative stress levels.

PubMed

Vats, Praveen; Singh, Vijay Kumar; Singh, Som Nath; Singh, Shashi Bala

2007-01-01

High altitude (HA) exposure usually leads to a significant weight loss in non-acclimatized humans. Anorexia is believed to be the main cause of this body weight loss. Appetite regulatory peptides, i.e. leptin and neuropeptide Y play a key role in food intake and energy homeostasis. Recent studies suggests increased oxidative stress during HA exposure. In present study effect of HA exposure on levels of leptin and NPY was evaluated along with N-acetyl cysteine (NAC) and vitamin E supplementation in relation to food intake and body weight changes. The study was conducted on 30 healthy male volunteers (age 19-29 years). Subjects were divided randomly into three groups of 10 each. Group 1 (placebo) supplemented with 400 mg of calcium gluconate, group 2 and 3 were supplemented with 400 mg of NAC and 400 mg vitamin E, respectively per day. The study was conducted at low altitude (320 m, Phase I), at HA 3600 m (Phase II) and at an altitude of 4580 m (Phase III). On HA exposure significant reduction in plasma leptin levels was observed in all the groups on day 2 (Phase II) along with decrease in food intake and reduction in body weight. Statistically significant increase in blood malondialdehyde (MDA) levels was seen in all the groups on HA exposure (Phase II, Day 2), but the maximum increase was in case of placebo group (65.1%) on day 2 (Phase II) in comparison to low altitude values. The decrease in energy intake was almost same in all the groups indicating that antioxidant supplementation did not provide any protection against HA anorexia. From the study, it may be concluded that leptin and oxidative stress possibly are not the key players for HA anorexia.

The Influence of Lead Exposure and Toxicity to Children's Neurological Development and School Performance.

ERIC Educational Resources Information Center

Kimball, Sarah L.

This report discusses the effects of lead exposure and toxicity on children's cognitive development and school performance and addresses the role of schools in prevention of lead poisoning. Sources of lead exposure include mining, smelting and refining activities, lead paint, leaded gasoline, and industrial emissions. The results of lead poisoning…

Maternal blood lead level during pregnancy in South Central Los Angeles.

PubMed

Rothenberg, S J; Manalo, M; Jiang, J; Khan, F; Cuellar, R; Reyes, S; Sanchez, M; Reynoso, B; Aguilar, A; Diaz, M; Acosta, S; Jauregui, M; Johnson, C

1999-01-01

Twenty-five years of public health efforts produced a striking reduction in lead exposure; the blood lead average in the United States has decreased to less than 20% of levels measured in the 1970s. However, poor minority groups that live in large urban centers are still at high risk for elevated lead levels. In this study, our data showed that pregnant immigrants (n = 1,428) who live in South Central Los Angeles--one of the most economically depressed regions of California--have significantly higher (p < .0001) blood lead levels (geometric mean = 2.3 microg/dl [0.11 micromol/l]) than 504 pregnant nonimmigrants (geometric mean = 1.9 microg/dl [0.09 micromol/l]). The most important factors associated with lower blood lead levels in both groups were younger age; more-recent date of blood sampling (i.e., decreasing secular trend); and blood sampling in mid-autumn, instead of mid-spring (i.e., seasonal trend). Blood lead levels of immigrants were strongly dependent on time elapsed since immigration to the United States; each natural log increase in years of residence was associated with an approximately 19% decrease in blood lead levels. Although blood lead means for both groups were almost the same as the estimated national average, 25 of the 30 cases of elevated blood lead (i.e., > or = 10 microg/dl [0.48 micromol/l) occurred in the immigrant group. The odds ratio (95% confidence intervals within parentheses) for having elevated blood lead levels (a) was 9.3 (1.9, 45.8) if the immigrant engaged in pica; (b) was 3.8 (1.4, 10.5) if the immigrant had low dietary calcium intake during pregnancy; and (c) was .65 (.43, .98) for every natural log unit increase of years of residence in the United States. The control of pica and dietary calcium intake may offer a means of reducing lead exposure in immigrants.

Ambient PM2.5 exposure and expected premature mortality to 2100 in India under climate change scenarios.

PubMed

Chowdhury, Sourangsu; Dey, Sagnik; Smith, Kirk R

2018-01-22

Premature mortality from current ambient fine particulate (PM 2.5 ) exposure in India is large, but the trend under climate change is unclear. Here we estimate ambient PM 2.5 exposure up to 2100 by applying the relative changes in PM 2.5 from baseline period (2001-2005) derived from Coupled Model Inter-comparison Project 5 (CMIP5) models to the satellite-derived baseline PM 2.5 . We then project the mortality burden using socioeconomic and demographic projections in the Shared Socioeconomic Pathway (SSP) scenarios. Ambient PM 2.5 exposure is expected to peak in 2030 under the RCP4.5 and in 2040 under the RCP8.5 scenario. Premature mortality burden is expected to be 2.4-4 and 28.5-38.8% higher under RCP8.5 scenario relative to the RCP4.5 scenario in 2031-2040 and 2091-2100, respectively. Improved health conditions due to economic growth are expected to compensate for the impact of changes in population and age distribution, leading to a reduction in per capita health burden from PM 2.5 for all scenarios except the combination of RCP8.5 exposure and SSP3.

Application of lead-acrylic compensating filters in chiropractic full spine radiography: a technical report

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

Buehler, M.T.; Hrejsa, A.F.

X-raying the entire spinal column in the standing position in a single exposure (mainly the AP projection) is an often-used chiropractic radiography procedure which has also found some application in medical scoliosis screening program. Aside from any controversy of clinical objectives or medical necessity, the primary agreed-upon requisite for such procedure is twofold; achieving the best possible film image quality with the least amount of radiation exposure to the patient. A popular method of accomplishing this objective is by the use of collimator-attached devices designed to selectively filter the primary x-ray beam in accordance with regional variations of body thicknessmore » and/or density. This study was conducted to evaluate the use of a new lead-acrylic filter system under specialized chiropractic conditions. In comparison to other available systems, it was concluded that this new system; a) is generally equivalent in its radiation dose reduction capabilities; b) is capable of producing full spine radiographs with good to above average image quality; and c) is appreciably easier to use.« less

Determination of shielding requirements for mammography.

PubMed

Okunade, Akintunde Akangbe; Ademoroti, Olalekan Albert

2004-05-01

Shielding requirements for mammography when considerations are to be given to attenuation by compression paddle, breast tissue, grid and image receptor (intervening materials) has been investigated. By matching of the attenuation and hardening properties, comparisons are made between shielding afforded by breast tissue materials (water, Lucite and 50%-50% adipose-glandular tissue) and some materials considered for shielding diagnostic x-ray beams, namely lead, steel and gypsum wallboard. Results show that significant differences exist between the thickness required to produce equal attenuation and that required to produce equal hardening of a given incident beam. While attenuation equivalent thickness produces equal exposure, it does not produce equal hardening. For shielding purposes, equivalence in exposure reduction without equivalence in penetrating power of an emerging beam does not amount to equivalence in shielding affordable by two different materials. Presented are models and results of sample calculations of additional shielding requirements apart from that provided by intervening materials. The shielding requirements for the integrated beam emerging from intervening materials are different from those for the integrated beam emerging from materials (lead/steel/gypsum wallboard) with attenuation equivalent thicknesses of these intervening materials.

Personal exposures to VOC in the upper end of the distribution—relationships to indoor, outdoor and workplace concentrations

NASA Astrophysics Data System (ADS)

Edwards, Rufus D.; Schweizer, Christian; Jantunen, Matti; Lai, Hak Kan; Bayer-Oglesby, Lucy; Katsouyanni, Klea; Nieuwenhuijsen, Mark; Saarela, Kristiina; Sram, Radim; Künzli, Nino

Evaluation of relationships between median residential indoor, indoor workplace and population exposures may obscure potential strategies for exposure reduction. Evaluation of participants with personal exposures above median levels in the EXPOLIS study in Athens, Helsinki, Oxford and Prague illustrated that these participants frequently showed a different relationship to indoor and workplace levels than that shown by the population median. Thus, prioritization of environments for control measures based on median exposures may exclude important areas where effectively focused control measures are possible, and may therefore have little impact on the highest and most harmful exposures. Further, personal exposures at the upper end of the distribution may exceed the US EPA inhalation reference concentration (Rfc), illustrated here using hexane, naphthalene and benzene. For example upper 90th percentile personal exposures to benzene in Athens and Prague were 64 and 27 μg m -3 with peak exposures of 217 and 38 μg m -3, respectively for non-ETS exposed participants relative to an Rfc of 30 μg m -3. Strategies to reduce exposures to individual compounds, therefore, may benefit from focus on the high end of the distribution to identify activities and behaviors that result in elevated exposures. Control strategies targeting activities that lead to exposures in the upper end of the distribution would reduce the variability associated with population median values by bringing the upper end of the exposure distribution closer to median values. Thus, compliance with health-based standards would be more protective of the higher exposed fraction of the population, in whom health effects would be more expected.

DETERMINANTS OF RESIDENTIAL LEAD EXPOSURE

EPA Science Inventory

The phase-out of leaded gasoline, and the accompanying decrease in lead emissions, resulted in a dramatic decline in mean blood lead levels from the late 1970s through the early 1990s. Nonetheless, lead exposures remain a public health concern. Long-term exposures to even low...

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

PubMed

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

2013-03-01

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

Lead exposure in Laysan albatross adults and chicks in Hawaii: Prevalence, risk factors, and biochemical effects

USGS Publications Warehouse

Work, Thierry M.; Smith, M.R.

1996-01-01

Prevalence of lead exposure and elevated tissue lead was determined in Laysan albatross (Diomedea immutabilis) in Hawaii. The relationship between lead exposure and proximity to buildings, between elevated blood lead and droopwing status, and elevated liver lead and presence of lead-containing paint chips in the proventriculus in albatross chicks was also examined. Finally, the effects of lead on the enzyme δ-amino-levulinic acid dehydratase (ALAD) was determined. There was a significant association between lead exposure or elevated tissue lead and proximity to buildings in albatross chicks and presence of lead paint chips in the proventriculus and elevated liver lead in carcasses. Although there was a significant association between elevated blood lead and droopwing chicks, there were notable exceptions. Prevalence of elevated tissue lead in albatross chicks was highest on Sand Island Midway and much less so on Kauai and virtually nonexistent in other areas. Prevalence of lead exposure decreased as numbers of buildings to which chicks were exposed on a given island decreased. Laysan albatross adults had minimal to no lead exposure. There was a significant negative correlation between blood lead concentration and ALAD activity in chicks. Based on ALAD activity, 0.03-0.05 μg/ml was the no effect range for blood lead in albatross chicks.

Effects of lead-spiked sediments on freshwater bivalve, Hyridella australis: linking organism metal exposure-dose-response.

PubMed

Marasinghe Wadige, Chamani P M; Taylor, Anne M; Maher, William A; Ubrihien, Rodney P; Krikowa, Frank

2014-04-01

Lead entering aquatic ecosystems adsorbs to sediments and has the potential to cause adverse effects on the health of benthic organisms. To evaluate the freshwater bivalve Hyridella australis as a bioindicator for sediment toxicity, their exposure-dose and response to lead contaminated sediments (< 0.01, 205 ± 9 and 419 ± 16 μg/g dry mass) was investigated in laboratory microcosms using 28 day exposures. Despite high concentrations of lead in the sediments, organisms accumulated low concentrations of lead in their tissues after 28 days of exposure (low treatment: 2.2 ± 0.2 μg/g dry mass, high treatment: 4.2 ± 0.1 μg/g dry mass), however, accumulated lead concentrations in lead exposed organisms were two fold (low treatment) and four fold (high treatment) higher than that of unexposed organisms (1.2 ± 0.3 μg/g dry mass). Accumulation of lead by H. australis may have occurred as analogues of calcium and magnesium. Labial palps accumulated significantly more lead than other tissues. Of the lead accumulated in the hepatopancreas, 83%-91% was detoxified and stored in metal rich granules. The proportions and concentrations of lead in this fraction increased with lead exposure, which suggests that lead detoxification pathway plays an important role in metal tolerance of H. australis. The biologically active lead was mainly present in the mitochondrial fraction which increased with lead exposure. Total antioxidant capacity of H. australis significantly decreased while lipid peroxidation and lysosomal membrane destabilation increased with lead exposure. This study showed a clear lead exposure-dose-response relationship and indicates that H. australis would be a good biomonitor for lead in freshwater ecosystems. Copyright © 2014 Elsevier B.V. All rights reserved.

A Framework for Widespread Replication of a Highly Spatially Resolved Childhood Lead Exposure Risk Model

PubMed Central

Kim, Dohyeong; Galeano, M. Alicia Overstreet; Hull, Andrew; Miranda, Marie Lynn

2008-01-01

Background Preventive approaches to childhood lead poisoning are critical for addressing this longstanding environmental health concern. Moreover, increasing evidence of cognitive effects of blood lead levels < 10 μg/dL highlights the need for improved exposure prevention interventions. Objectives Geographic information system–based childhood lead exposure risk models, especially if executed at highly resolved spatial scales, can help identify children most at risk of lead exposure, as well as prioritize and direct housing and health-protective intervention programs. However, developing highly resolved spatial data requires labor-and time-intensive geocoding and analytical processes. In this study we evaluated the benefit of increased effort spent geocoding in terms of improved performance of lead exposure risk models. Methods We constructed three childhood lead exposure risk models based on established methods but using different levels of geocoded data from blood lead surveillance, county tax assessors, and the 2000 U.S. Census for 18 counties in North Carolina. We used the results to predict lead exposure risk levels mapped at the individual tax parcel unit. Results The models performed well enough to identify high-risk areas for targeted intervention, even with a relatively low level of effort on geocoding. Conclusions This study demonstrates the feasibility of widespread replication of highly spatially resolved childhood lead exposure risk models. The models guide resource-constrained local health and housing departments and community-based organizations on how best to expend their efforts in preventing and mitigating lead exposure risk in their communities. PMID:19079729

Windows of lead exposure sensitivity, attained height, and body mass index at 48 months.

PubMed

Afeiche, Myriam; Peterson, Karen E; Sánchez, Brisa N; Schnaas, Lourdes; Cantonwine, David; Ettinger, Adrienne S; Solano-González, Maritsa; Hernández-Avila, Mauricio; Hu, Howard; Téllez-Rojo, Martha M

2012-06-01

To examine longitudinal associations of prenatal, infancy, and early childhood lead exposure during sensitive periods with height and body mass index (BMI). A total of 773 participants were recruited between 1994 and 2005 in Mexico City. Lead exposure history categories were constructed for the prenatal period (maternal patellar lead concentration) and for infancy and childhood (mean child blood lead concentration at birth to 24 months and 30-48 months, respectively). Linear regression models were used to study lead exposure history with height and BMI at 48 months. Mean height at age 48 months was significantly lower in children with a blood lead level exceeding the median during infancy (-0.84 cm; 95% CI, -1.42 to -0.25) than in children with a level below the median. Prenatal lead exposure was not associated with height at 48 months. Results for attained BMI generally trended in the same direction as for height. Our findings suggest an effect of lead exposure early in life on height attainment at 48 months, with the exposure window of greatest sensitivity in infancy. Copyright © 2012 Mosby, Inc. All rights reserved.

Radiation dosage during pediatric diagnostic or interventional cardiac catheterizations using the “air gap technique” and an aggressive “as low as reasonably achievable” radiation reduction protocol in patients weighing <20 kg

PubMed Central

Osei, Frank A; Hayman, Joshua; Sutton, Nicole J; Pass, Robert H

2016-01-01

Background: Cardiac catheterizations expose both the patient and staff to the risks of ionizing radiation. Studies using the “air gap” technique (AGT) in various radiological procedures indicate that its use leads to reduction in radiation exposure but there are no data on its use for pediatric cardiac catheterization. The aim of this study was to retrospectively review the radiation exposure data for children weighing <20 kg during cardiac catheterizations using AGT and an “as low as reasonably achievable (ALARA)” radiation reduction protocol. Patients and Methods: All patients weighing <20 kg who underwent cardiac catheterization at the Children's Hospital at Montefiore (CHAM), New York, the United States from 05/2011 to 10/2013 were included. Transplant patients who underwent routine endomyocardial biopsy and those who had surgical procedures at the time of the catheterizations were excluded. The ALARA protocol was used in concert with AGT with the flat panel detector positioned 110 cm from the patient. Demographics, procedural data, and patient radiation exposure levels were collected and analyzed. Results: One-hundred and twenty-seven patients underwent 151 procedures within the study period. The median age was 1.2 years (range: 1 day to 7.9 years) and median weight was 8.8 kg (range: 1.9-19.7). Eighty-nine (59%) of the procedures were interventional. The median total fluoro time was 13 min [interquartile range (IQR) 7.3-21.8]. The median total air Kerma (K) product was 55.6 mGy (IQR 17.6-94.2) and dose area product (DAP) was 189 Gym2 (IQR 62.6-425.5). Conclusion: Use of a novel ALARA and AGT protocol for cardiac catheterizations in children markedly reduced radiation exposure to levels far below recently reported values. Abbreviations: AGT: Air gap technique, ALARA: As low as reasonably achievable. PMID:27011686

Lead exposure in Canada geese of the Eastern Prairie Population

USGS Publications Warehouse

DeStefano, S.; Brand, C.J.; Rusch, D.H.; Finley, Daniel L.; Gillespie, M.M.

1991-01-01

We monitored lead exposure in Eastern Prairie Population Canada geese during summer-winter, 1986-1987 and 1987-1988 at 5 areas. Blood lead concentrations in geese trapped during summer at Cape Churchill Manitoba were below levels indicative of recent lead exposure (0.18 ppm). Geese exposed to lead (≥0.18 ppm blood lead) increased to 7.6% at Oak Hammock Wildlife Management Area (WMA), southern Manitoba, where lead shot was still in use, and to 10.0% at Roseau River WMA, northern Minnesota, when fall-staging geese were close to a source of lead shot in Manitoba. Proportion of birds exposed to lead dropped to <2% at Lac Qui Parle WMA, Minnesota, a steel shot zone since 1980. On the wintering grounds at Swan Lake National Wildlife Refuge in Missouri, 4.9% of all geese showed exposure to lead before the hunting season. Lead exposure rose to 10.0% after hunting ended and then decreased to 5.2% in late winter. Incidence of lead shot in gizzards and concentrations of lead in livers supported blood assay data. Soil samples indicated that lead shot continues to be available to geese at Swan Lake, even though the area was established as a non-toxic shot zone in 1978. Steel shot zones have reduced lead exposure in the Eastern Prairie Population, but lead shot persists in the environment and continues to account for lead exposure and mortality in Eastern Prairie Population Canada geese.

Chemical form of selenium differentially influences DNA repair pathways following exposure to lead nitrate.

PubMed

McKelvey, Shauna M; Horgan, Karina A; Murphy, Richard A

2015-01-01

Lead, an environmental toxin is known to induce a broad range of physiological and biochemical dysfunctions in humans through a number of mechanisms including the deactivation of antioxidants thus leading to generation of reactive oxygen species (ROS) and subsequent DNA damage. Selenium on the other hand has been proven to play an important role in the protection of cells from free radical damage and oxidative stress, though its effects are thought to be form and dose dependent. As the liver is the primary organ required for metabolite detoxification, HepG2 cells were chosen to assess the protective effects of various selenium compounds following exposure to the genotoxic agent lead nitrate. Initially DNA damage was quantified using a comet assay, gene expression patterns associated with DNA damage and signalling were also examined using PCR arrays and the biological pathways which were most significantly affected by selenium were identified. Interestingly, the organic type selenium compounds (selenium yeast and selenomethionine) conferred protection against lead induced DNA damage in HepG2 cells; this is evident by reduction in the quantity of DNA present in the comet tail of cells cultured in their presence with lead. This trend also followed through the gene expression changes noted in DNA damage pathways analysed. These results were in contrast with those of inorganic sodium selenite which promoted lead induced DNA damage evident in both the comet assay results and the gene expression analysis. Over all this study provided valuable insights into the effects which various selenium compounds had on the DNA damage and signalling pathway indicating the potential for using organic forms of selenium such as selenium enriched yeast to protect against DNA damaging agents. Copyright © 2014 Elsevier GmbH. All rights reserved.

Household interventions for preventing domestic lead exposure in children.

PubMed

Yeoh, Berlinda; Woolfenden, Susan; Lanphear, Bruce; Ridley, Greta F; Livingstone, Nuala; Jorgensen, Emile

2014-12-15

Lead poisoning is associated with physical, cognitive and neurobehavioural impairment in children and trials have tested many household interventions to prevent lead exposure. This is an update of the original review by the same authors first published in 2008. To determine the effectiveness of household interventions in preventing or reducing lead exposure in children as measured by reductions in blood lead levels and/or improvements in cognitive development. We identified trials through electronic searches of CENTRAL (2012, Issue 1), MEDLINE (1948 to January Week 1 2012), EMBASE (1980 to Week 2 2012), CINAHL (1937 to January 2012), PsycINFO (1887 to January Week 2 2012), ERIC (1966 to January 2012), Sociological Abstracts (1952 to January 2012), Science Citation Index (1970 to 20 January 2012), ZETOC (20 January 2012), LILACS (20 January 2012), Dissertation Abstracts (late 1960s to January 2012), ClinicalTrials.gov (19 January 2012), Current Controlled Trials (19 January 2012), Australian New Zealand Clinical Trials Registry (19 January 2012) and the National Research Register Archive. We also contacted experts to find unpublished studies. Randomised and quasi-randomised controlled trials of household educational or environmental interventions to prevent lead exposure in children where at least one standardised outcome measure was reported. Two authors independently reviewed all eligible studies for inclusion, assessed risk of bias and extracted data. We contacted trialists to obtain missing information. We included 14 studies (involving 2656 children). All studies reported blood lead level outcomes and none reported on cognitive or neurobehavioural outcomes. We put studies into subgroups according to their intervention type. We performed meta-analysis of both continuous and dichotomous data for subgroups where appropriate. Educational interventions were not effective in reducing blood lead levels (continuous: mean difference (MD) 0.02, 95% confidence interval (CI) -0.09 to 0.12, I(2) = 0 (log transformed); dichotomous ≥ 10µg/dL (≥ 0.48 µmol/L): relative risk (RR) 1.02, 95% CI 0.79 to 1.30, I(2)=0; dichotomous ≥ 15µg/dL (≥ 0.72 µmol/L): RR 0.60, 95% CI 0.33 to 1.09, I(2) = 0). Meta-analysis for the dust control subgroup also found no evidence of effectiveness (continuous: MD -0.15, 95% CI -0.42 to 0.11, I(2) = 0.9 (log transformed); dichotomous ≥ 10µg/dL (≥ 0.48 µmol/L): RR 0.93, 95% CI 0.73 to 1.18, I(2) =0; dichotomous ≥ 15µg/dL (≥ 0.72 µmol/L): RR 0.86, 95% CI 0.35 to 2.07, I(2) = 0.56). When meta-analysis for the dust control subgroup was adjusted for clustering, no statistical significant benefit was incurred. The studies using soil abatement (removal and replacement) and combination intervention groups were not able to be meta-analysed due to substantial differences between studies. Based on current knowledge, household educational or dust control interventions are ineffective in reducing blood lead levels in children as a population health measure. There is currently insufficient evidence to draw conclusions about the effectiveness of soil abatement or combination interventions.Further trials are required to establish the most effective intervention for prevention of lead exposure. Key elements of these trials should include strategies to reduce multiple sources of lead exposure simultaneously using empirical dust clearance levels. It is also necessary for trials to be carried out in developing countries and in differing socioeconomic groups in developed countries.

Household interventions for preventing domestic lead exposure in children.

PubMed

Yeoh, Berlinda; Woolfenden, Susan; Lanphear, Bruce; Ridley, Greta F; Livingstone, Nuala

2012-04-18

Lead poisoning is associated with physical, cognitive and neurobehavioural impairment in children and trials have tested many household interventions to prevent lead exposure. This is an update of the original review by the same authors first published in 2008. To determine the effectiveness of household interventions in preventing or reducing lead exposure in children as measured by reductions in blood lead levels and/or improvements in cognitive development. We identified trials through electronic searches of CENTRAL (The Cochrane Library, 2010, Issue 2), MEDLINE (1948 to April Week 1 2012), EMBASE (1980 to 2012 Week 2), CINAHL (1937 to 20 Jan 2012), PsycINFO (1887 to Dec week 2 2011), ERIC (1966 to 17 Jan 2012), Sociological Abstracts (1952 to 20 January 2012), Science Citation Index (1970 to 20 Jan 2012), ZETOC (20 Jan 2012), LILACS (20 Jan 2012), Dissertation Abstracts (late 1960s to Jan 2012), ClinicalTrials.gov (20 Jan 2012), Current Controlled Trials (Jan 2012), Australian New Zealand Clinical Trials Registry (Jan 2012) and the National Research Register Archive. We also contacted experts to find unpublished studies. Randomised and quasi-randomised controlled trials of household educational or environmental interventions to prevent lead exposure in children where at least one standardised outcome measure was reported. Two authors independently reviewed all eligible studies for inclusion, assessed risk of bias and extracted data. We contacted trialists to obtain missing information. We included 14 studies (involving 2656 children). All studies reported blood lead level outcomes and none reported on cognitive or neurobehavioural outcomes. We put studies into subgroups according to their intervention type. We performed meta-analysis of both continuous and dichotomous data for subgroups where appropriate. Educational interventions were not effective in reducing blood lead levels (continuous: mean difference (MD) 0.02, 95% confidence interval (CI) -0.09 to 0.12, I(2) = 0 (log transformed); dichotomous ≥ 10µg/dL (≥ 0.48 µmol/L): relative risk (RR) 1.02, 95% CI 0.79 to 1.30, I(2)=0; dichotomous ≥ 15µg/dL (≥ 0.72 µmol/L): RR 0.60, 95% CI 0.33 to 1.09, I(2) = 0). Meta-analysis for the dust control subgroup also found no evidence of effectiveness (continuous: MD -0.15, 95% CI -0.42 to 0.11, I(2) = 0.9 (log transformed); dichotomous ≥ 10µg/dL (≥ 0.48 µmol/L): RR 0.93, 95% CI 0.73 to 1.18, I(2) =0; dichotomous ≥ 15µg/dL (≥ 0.72 µmol/L): RR 0.86, 95% CI 0.35 to 2.07, I(2) = 0.56). When meta-analysis for the dust control subgroup was adjusted for clustering, no statistical significant benefit was incurred. The studies using soil abatement (removal and replacement) and combination intervention groups were not able to be meta-analysed due to substantial differences between studies. Based on current knowledge, household educational or dust control interventions are ineffective in reducing blood lead levels in children as a population health measure. There is currently insufficient evidence to draw conclusions about the effectiveness of soil abatement or combination interventions.Further trials are required to establish the most effective intervention for prevention of lead exposure. Key elements of these trials should include strategies to reduce multiple sources of lead exposure simultaneously using empirical dust clearance levels. It is also necessary for trials to be carried out in developing countries and in differing socioeconomic groups in developed countries.

Effect of flow rate and lead/copper pipe sequence on lead release from service lines.

PubMed

Cartier, Clément; Arnold, Roger B; Triantafyllidou, Simoni; Prévost, Michèle; Edwards, Marc

2012-09-01

A pilot experiment examined lead leaching from four representative configurations of service lines including: (1) 100% lead (Pb), (2) 100% copper (Cu), (3) 50% Pb upstream of 50% Cu, and (4) 50% Pb-downstream of 50% Cu using a range of flow rates. The cumulative mass of lead release indicated that a typical partial replacement configuration (50% lead downstream of copper) did not provide a net reduction in lead when compared to 100% lead pipe (85 mg for 50% Pb-downstream versus 83 mg for 100%-Pb) due to galvanic and deposition corrosion. The partially replaced service line configuration also had a much greater likelihood of producing water with "spikes" of lead particulates at higher flow rates, while tending to produce lower levels of lead at very low flow rates. After the first 214 days the galvanic current between copper and lead was only reduced by 34%, proving that galvanic impacts can be highly persistent even in water with optimized corrosion control by dosing of zinc orthophosphate. Finally, this experiment raises concern about the low flow rates used during some prior home sampling events, which may underestimate exposure to lead during normal water use, especially when galvanic Pb:Cu connections are present. Copyright © 2012 Elsevier Ltd. All rights reserved.

SHORT-TERM EXPOSURE TO ALCOHOL IN RATS AFFECTS BRAIN LEVELS OF ANANDAMIDE, OTHER N-ACYLETHANOLAMINES AND 2-ARACHIDONOYL-GLYCEROL

PubMed Central

Rubio, Marina; McHugh, Douglas; Fernández-Ruiz, Javier; Bradshaw, Heather; Walker, J. Michael

2010-01-01

Chronic alcohol exposure leads to significant changes in the levels of endocannabinoids and their receptors in the brains of humans and laboratory animals, as well as in cultured neuronal cells. However, little is known about the effects of short-term periods of alcohol exposure. In the present study, we examined the changes in endocannabinoid levels (anandamide and 2-arachidonoylglycerol), as well as four additional N-acylethanolamines, in four brain regions of rats exposed to alcohol through the liquid diet for a period of 24 hours. The levels of N-acylethanolamines were diminished 24 hours after the onset of alcohol exposure. This was particularly evident for anandamide in the hypothalamus, amygdala and caudate-putamen, for N-palmitoylethanolamine in the caudate-putamen, for N-oleoylethanolamine in the hypothalamus, caudate-putamen and prefrontal cortex, and for N-stearoylethanolamine in the amygdala. The only exception was N-linoleoylethanolamine for which the levels increased in the amygdala after the exposure to alcohol. The levels of the other major endocannabinoid, 2-arachidonoylglycerol, were also reduced with marked effects in the prefrontal cortex. These results support the notion that short-term alcohol exposure reduces endocannabinoid levels in the brain accompanied by a reduction in several related N-acylethanolamines. PMID:17574742

Long-term Reductions in the Population of GABAergic Interneurons in the Mouse Hippocampus following Developmental Ethanol Exposure.

PubMed

Bird, Clark W; Taylor, Devin H; Pinkowski, Natalie J; Chavez, G Jill; Valenzuela, C Fernando

2018-07-15

Developmental exposure to ethanol leads to a constellation of cognitive and behavioral abnormalities known as Fetal Alcohol Spectrum Disorders (FASDs). Many cell types throughout the central nervous system are negatively impacted by gestational alcohol exposure, including inhibitory, GABAergic interneurons. Little evidence exists, however, describing the long-term impact of fetal alcohol exposure on survival of interneurons within the hippocampal formation, which is critical for learning and memory processes that are impaired in individuals with FASDs. Mice expressing Venus yellow fluorescent protein in inhibitory interneurons were exposed to vaporized ethanol during the third trimester equivalent of human gestation (postnatal days 2-9), and the long-term effects on interneuron numbers were measured using unbiased stereology at P90. In adulthood, interneuron populations were reduced in every hippocampal region examined. Moreover, we found that a single exposure to ethanol at P7 caused robust activation of apoptotic neurodegeneration of interneurons in the hilus, granule cell layer, CA1 and CA3 regions of the hippocampus. These studies demonstrate that developmental ethanol exposure has a long-term impact on hippocampal interneuron survivability, and may provide a mechanism partially explaining deficits in hippocampal function and hippocampus-dependent behaviors in those afflicted with FASDs. Copyright © 2018 IBRO. Published by Elsevier Ltd. All rights reserved.

Occupational exposure to solar radiation in Australia: who is exposed and what protection do they use?

PubMed

Carey, Renee N; Glass, Deborah C; Peters, Susan; Reid, Alison; Benke, Geza; Driscoll, Timothy R; Fritschi, Lin

2014-02-01

Solar ultraviolet radiation (UVR) exposure is widely recognised as a leading cause of skin cancer, with outdoor workers being particularly at risk. Little is known on a national level about how many workers are exposed to solar radiation, the circumstances in which they are exposed, or their use of protective measures. The Australian Work Exposures Study (AWES) was a cross-sectional telephone survey of 5,023 Australian workers aged 18 to 65. A subset of 1,113 respondents who indicated they worked outdoors was asked about their exposure to solar radiation in terms of the amount of time they spent working outdoors, their working location and their use of sun protective measures. A total of 1,100 respondents (22% overall) were assessed as being exposed to solar radiation at work. Exposure was more likely among males and those residing in lower socioeconomic and regional areas. Sun protection was used by 95% of the respondents, although the level of protection varied among workers, with only 8.7% classified as fully protected. This study provides valuable information regarding solar exposure that has not previously been available. The results of this study will inform strategies for risk reduction. © 2014 The Authors. ANZJPH © 2014 Public Health Association of Australia.

Household concentrations and personal exposure of PM2.5 among urban residents using different cooking fuels.

PubMed

Li, Tianxin; Cao, Suzhen; Fan, Delong; Zhang, Yaqun; Wang, Beibei; Zhao, Xiuge; Leaderer, Brian P; Shen, Guofeng; Zhang, Yawei; Duan, Xiaoli

2016-04-01

Exposure to PM2.5 is a leading environmental risk factor for many diseases and premature deaths, arousing growing public concerns. In this study, indoor and outdoor PM2.5 concentrations were investigated during the heating and non-heating seasons in an urban area in northwest China. Personal inhalation exposure levels among different age groups were evaluated, and the difference attributable to different cooking fuels including coal, gas and electricity, was discussed. The average concentrations of PM2.5 in the kitchen and the bedroom were 125±51 and 119±64μg/m(3) during the heating season, and 80±67 and 80±50μg/m(3) during the non-heating season, respectively. Indoor PM2.5, from indoor combustion sources but also outdoor penetration, contributed to about 75% of the total PM2.5 exposure. Much higher indoor concentrations and inhalation exposure levels were found in households using coal for cooking compared to those using gas and electricity. Changing from coal to gas or electricity for cooking could result in a reduction of PM2.5 in the kitchen by 40-70% and consequently lower inhalation exposure levels, especially for children and women. Copyright © 2016 Elsevier B.V. All rights reserved.

Control of occupational exposure to hexavalent chromium and ozone in tubular wire arc-welding processes by replacement of potassium by lithium or by addition of zinc.

PubMed

Dennis, John H; French, Michael J; Hewitt, Peter J; Mortazavi, Seyed B; Redding, Christopher A J

2002-01-01

Hexavalent chromium [Cr(VI)] and ozone are produced in many arc-welding processes. Cr(VI) is formed when welding with chromium-containing alloys and is a suspected carcinogen. Ozone is formed by the action of ultraviolet light from the arc on oxygen and can cause severe irritation to the eyes and mucous membranes. Previous work has demonstrated that reduction of sodium and potassium in manual metal arc-welding electrodes leads to substantial reductions in Cr(VI) concentrations in the fume as well as a reduction in the fume formation rate. In this paper replacement of potassium by lithium in a tubular wire welding electrode (self-shielding flux-cored) is shown to give reductions in Cr(VI) concentrations and fume formation rates. Previous work has also demonstrated that use of a tubular wire (metal cored) containing 1% zinc can, under certain conditions, result in a reduction in Cr(VI) formation rate and in ozone concentration near the arc but with a rise in the total fume formation rate. The effects of different shield gases and different levels of zinc are examined. An experimental chromium-containing tubular wire with 1% zinc was used with the following shield gases: argon, Argoshield 5, Argoshield 20, Helishield 101, Ar + 2% CO2, Ar + 5% CO2, Ar + 1% O2 and Ar + 2% O2. The wire gave > 98% reduction in Cr(VI) formation rate compared to the control wire provided the shield gas contained no oxygen. When the shield gas did contain oxygen, 1% zinc enhanced Cr(VI) formation rate, resulting in more than double the rates measured when welding with the control wire. Experiments with zinc concentrations, from 0.018 to 0.9% using Helishield 101, gave results indicating that there is an optimum zinc concentration from the point of view of Cr(VI) reduction. Implications of the use of lithium or zinc on the overall exposure risk are discussed.

Childhood Lead Poisoning: Conservative Estimates of the Social and Economic Benefits of Lead Hazard Control

PubMed Central

Gould, Elise

2009-01-01

Background This study is a cost–benefit analysis that quantifies the social and economic benefits to household lead paint hazard control compared with the investments needed to minimize exposure to these hazards. Objectives This research updates estimates of elevated blood lead levels among a cohort of children ≤ 6 years of age and compiles recent research to determine a range of the costs of lead paint hazard control ($1–$11 billion) and the benefits of reduction attributed to each cohort for health care ($11–$53 billion), lifetime earnings ($165–$233 billion), tax revenue ($25–$35 billion), special education ($30–$146 million), attention deficit–hyperactivity disorder ($267 million), and the direct costs of crime ($1.7 billion). Results Each dollar invested in lead paint hazard control results in a return of $17–$221 or a net savings of $181–269 billion. Conclusions There are substantial returns to investing in lead hazard control, particularly targeted at early intervention in communities most likely at risk. Given the high societal costs of inaction, lead hazard control appears to be well worth the price. PMID:19654928

Environmental Lead Pollution and Elevated Blood Lead Levels Among Children in a Rural Area of China

PubMed Central

Lin, Sihao; Yu, Ignatius Tak Sun; Tang, Wenjuan; Miao, Jianying; Li, Jin; Wu, Siying; Lin, Xing

2011-01-01

Objectives. We investigated environmental lead pollution and its impact on children's blood lead levels (BLLs) in a rural area of China. Methods. In 2007, we studied 379 children younger than 15 years living in 7 villages near lead mines and processing plants, along with a control group of 61 children from another village. We determined their BLLs and collected environmental samples, personal data, and information on other potential exposures. We followed approximately 86% of the children who had high BLLs (> 15 μg/dL) for 1 year. We determined factors influencing BLLs by multivariate linear regression. Results. Lead concentrations in soil and household dust were much higher in polluted villages than in the control village, and more children in the polluted area than in the control village had elevated BLLs (87%, 16.4 μg/dL vs 20%, 7.1 μg/dL). Increased BLL was independently associated with environmental lead levels. We found a significant reduction of 5 micrograms per deciliter when we retested children after 1 year. Conclusions. Our data show that the lead industry caused serious environmental pollution that led to high BLLs in children living nearby. PMID:21421950

Environmental lead pollution and elevated blood lead levels among children in a rural area of China.

PubMed

Lin, Sihao; Wang, Xiaorong; Yu, Ignatius Tak Sun; Tang, Wenjuan; Miao, Jianying; Li, Jin; Wu, Siying; Lin, Xing

2011-05-01

We investigated environmental lead pollution and its impact on children's blood lead levels (BLLs) in a rural area of China. In 2007, we studied 379 children younger than 15 years living in 7 villages near lead mines and processing plants, along with a control group of 61 children from another village. We determined their BLLs and collected environmental samples, personal data, and information on other potential exposures. We followed approximately 86% of the children who had high BLLs (> 15 μg/dL) for 1 year. We determined factors influencing BLLs by multivariate linear regression. Lead concentrations in soil and household dust were much higher in polluted villages than in the control village, and more children in the polluted area than in the control village had elevated BLLs (87%, 16.4 μg/dL vs 20%, 7.1 μg/dL). Increased BLL was independently associated with environmental lead levels. We found a significant reduction of 5 micrograms per deciliter when we retested children after 1 year. Our data show that the lead industry caused serious environmental pollution that led to high BLLs in children living nearby.

Amplitude Reduction and Phase Shifts of Melatonin, Cortisol and Other Circadian Rhythms after a Gradual Advance of Sleep and Light Exposure in Humans

PubMed Central

Dijk, Derk-Jan; Duffy, Jeanne F.; Silva, Edward J.; Shanahan, Theresa L.; Boivin, Diane B.; Czeisler, Charles A.

2012-01-01

Background The phase and amplitude of rhythms in physiology and behavior are generated by circadian oscillators and entrained to the 24-h day by exposure to the light-dark cycle and feedback from the sleep-wake cycle. The extent to which the phase and amplitude of multiple rhythms are similarly affected during altered timing of light exposure and the sleep-wake cycle has not been fully characterized. Methodology/Principal Findings We assessed the phase and amplitude of the rhythms of melatonin, core body temperature, cortisol, alertness, performance and sleep after a perturbation of entrainment by a gradual advance of the sleep-wake schedule (10 h in 5 days) and associated light-dark cycle in 14 healthy men. The light-dark cycle consisted either of moderate intensity ‘room’ light (∼90–150 lux) or moderate light supplemented with bright light (∼10,000 lux) for 5 to 8 hours following sleep. After the advance of the sleep-wake schedule in moderate light, no significant advance of the melatonin rhythm was observed whereas, after bright light supplementation the phase advance was 8.1 h (SEM 0.7 h). Individual differences in phase shifts correlated across variables. The amplitude of the melatonin rhythm assessed under constant conditions was reduced after moderate light by 54% (17–94%) and after bright light by 52% (range 12–84%), as compared to the amplitude at baseline in the presence of a sleep-wake cycle. Individual differences in amplitude reduction of the melatonin rhythm correlated with the amplitude of body temperature, cortisol and alertness. Conclusions/Significance Alterations in the timing of the sleep-wake cycle and associated bright or moderate light exposure can lead to changes in phase and reduction of circadian amplitude which are consistent across multiple variables but differ between individuals. These data have implications for our understanding of circadian organization and the negative health outcomes associated with shift-work, jet-lag and exposure to artificial light. PMID:22363414

Breakfast Skipping, Extreme Commutes, and the Sex Composition at Birth.

PubMed

Mazumder, Bhashkar; Seeskin, Zachary

2015-01-01

A growing body of literature has shown that environmental exposures in the period around conception can affect the sex ratio at birth through selective attrition that favors the survival of female conceptuses. Glucose availability is considered a key indicator of the fetal environment, and its absence as a result of meal skipping may inhibit male survival. We hypothesize that breakfast skipping during pregnancy may lead to a reduction in the fraction of male births. Using time use data from the United States we show that women with commute times of 90 minutes or longer are 20 percentage points more likely to skip breakfast. Using U.S. census data we show that women with commute times of 90 minutes or longer are 1.2 percentage points less likely to have a male child under the age of 2. Under some assumptions, this implies that routinely skipping breakfast around the time of conception leads to a 6 percentage point reduction in the probability of a male child. Skipping breakfast during pregnancy may therefore constitute a poor environment for fetal health more generally.

Dietary exposure to lead of adults in Shenzhen city, China.

PubMed

Pan, Liubo; Wang, Zhou; Peng, Zhaoqiong; Liu, Guihua; Zhang, Huimin; Zhang, Jinzhou; Jiang, Jie; Pathiraja, Nimal; Xiao, Ying; Jiao, Rui; Huang, Wei

2016-07-01

Lead, a ubiquitous heavy metal, can be found in the environment and food. The present study is the first to estimate the lead dietary exposure of Shenzhen adults (≥ 20 years old) in various age-gender subgroups, and to assess the associated health risk. Food samples that represented the Shenzhen people's dietary pattern were collected and prepared for analysis. Lead was determined in 13 food groups using 276 individual cooked samples by inductively coupled plasma-mass spectrometry (ICP-MS). Dietary exposures were estimated by combining the analytical results with the local food consumption data of Shenzhen adults. The mean and 95th percentile lead exposure of Shenzhen adults were 0.59-0.73 and 0.75-0.94 μg kg(-1) bw day(-1), respectively. In all food groups, the highest lead exposure was from 'Eggs and their products' (42.4-51.6% of the total exposure); preserved eggs being the main contributor. The other major contributors to lead exposure of Shenzhen adults were 'Fish and seafood, and their products' (14.3-16.7% of the total exposure) and 'Vegetables and their products' (15.5-16.2% of the total exposure). The margin of exposure (MOE) approach was used for the risk assessment of lead, and the results showed that the risk was considered to be low in all age-gender groups for Shenzhen adults. However, having considered a number of toxic effects of lead, it is suggested that more efforts should be made to reduce the lead levels in foodstuff for Shenzhen adults.

Short-term cadmium exposure induces gas exchanges, morphological and ultrastructural disturbances in mangrove Avicennia schaueriana young plants.

PubMed

Garcia, Janaina S; Dalmolin, Ândrea C; Cortez, Priscila A; Barbeira, Paulo S; Mangabeira, Pedro A O; França, Marcel G C

2018-06-01

Mangroves have been subject to more metal contamination, including cadmium (Cd). This study evaluated if a relatively short Cd exposure may induce metabolic, morphological and ultrastructural cell disturbance in Avicennia schaueriana. Cd induced evident constraints to seedlings since there was reduction in leaf gas exchanges and the plants did not survive for more than 10 days at a higher Cd exposure in controlled conditions. The highest Cd accumulation was observed in roots and gradually less in stem and leaves. Cadmium induced lignin deposition was observed in xylem cells of all vegetative organs. Intense sclerification in xylem cells, endoderm and change in the hypoderm organization were also detected. Cadmium clearly induced chloroplast deformities with ruptures of its membranes, thylakoids and core and provoked cytoplasm disorganization. These metal constraints under natural conditions for long term can lead to the accumulation of cellular and metabolic damages and jeopardize seedlings establishment and local biodiversity. Copyright © 2018 Elsevier Ltd. All rights reserved.

Exposure assessment of environmental organic chemicals at contaminated sites: a multicompartment modelling approach.

PubMed

Matthies, M

2003-04-11

For the prevention of future damages from chemicals at large contaminated sites, all transfer pathways leading to the exposure of man and vulnerable ecosystems have to be taken into account. For organic contaminants, the uptake into vegetation is the major entry route for the transfer into the food chains. Lipophilic substances are taken up by roots but are not translocated with the transpiration stream. Atmospheric background concentrations have a significant impact on foliage contamination due to the effective gaseous and particle deposition. Vegetables can also be contaminated after irrigation with contaminated water supplied by groundwater wells. By means of a multicompartment model, the various uptake processes into roots and foliage as well as the transformation and translocation processes are described and the concentration pattern resulting from daily irrigation with methyl-t-butyl ether in the edible parts is simulated. The results demonstrate the advantage of a dynamic multicompartment model over the static environmental quality standard approach in terms of derivation of possible exposure reduction measures for organic chemicals.

Exposure therapy leads to enhanced late frontal positivity in 8- to 13-year-old spider phobic girls

PubMed Central

Leutgeb, Verena; Schäfer, Axel; Köchel, Angelika; Schienle, Anne

2012-01-01

Neurobiological studies have demonstrated that psychotherapy is able to alter brain function in adults, however little exists on this topic with respect to children. This waiting-list controlled investigation focused on therapy-related changes of the P300 and the late positive potential (LPP) in 8- to 13-year-old spider phobic girls. Thirty-two patients were presented with phobia-relevant, generally disgust-inducing, fear-inducing, and affectively neutral pictures while an electroencephalogram was recorded. Participants received one session of up to 4 h of cognitive-behavioral exposure therapy. Treated children showed enhanced amplitudes of the LPP at frontal sites in response to spider pictures. This result is interpreted to reflect an improvement in controlled attentional engagement and is in line with already existing data for adult females. Moreover, the girls showed a therapy-specific reduction in overall disgust proneness, as well as in experienced arousal and disgust when viewing disgust pictures. Thus, exposure therapy seems to have broad effects in children. PMID:22388043

Radiation exposure reduction by use of Kevlar cassettes in the neonatal nursery

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

Herman, M.W.; Mak, H.K.; Lachman, R.S.

1987-05-01

A study was performed to determine whether the use of Kevlar cassettes in the neonatal intensive care nursery would reduce radiation exposure to patients. The radiation dose to the neonates was measured by using thermoluminescent dosimeters. In addition, the attenuation of the Kevlar cassettes and the sensitivity of the film-screen combination were compared with the previously used system. The greatest radiation reduction using a mobile X-ray unit was 27%; based on sensitivity measurements, the theoretical reduction averaged 38%. The reduction in radiation exposure resulted from reduced attenuation by the Kevlar cassette.

Radiation exposure reduction by use of Kevlar cassettes in the neonatal nursery.

PubMed

Herman, M W; Mak, H K; Lachman, R S

1987-05-01

A study was performed to determine whether the use of Kevlar cassettes in the neonatal intensive care nursery would reduce radiation exposure to patients. The radiation dose to the neonates was measured by using thermoluminescent dosimeters. In addition, the attenuation of the Kevlar cassettes and the sensitivity of the film-screen combination were compared with the previously used system. The greatest radiation reduction using a mobile X-ray unit was 27%; based on sensitivity measurements, the theoretical reduction averaged 38%. The reduction in radiation exposure resulted from reduced attenuation by the Kevlar cassette.

Determinants of bone and blood lead concentrations in the early postpartum period

PubMed Central

Brown, M. J.; Hu, H.; Gonzales-Cossio, T.; Peterson, K.; Sanin, L.; Kageyama, M. d.; Palazuelos, E.; Aro, A.; Schnaas, L.; Hernandez-Avila, M.

2000-01-01

OBJECTIVE—This study investigated determinants of bone and blood lead concentrations in 430 lactating Mexican women during the early postpartum period and the contribution of bone lead to blood lead.
METHODS—Maternal venous lead was measured at delivery and postpartum, and bone lead concentrations, measured with in vivo K-x ray fluorescence, were measured post partum. Data on environmental exposure, demographic characteristics, and maternal factors related to exposure to lead were collected by questionnaire. Linear regression was used to examine the relations between bone and blood lead, demographics, and environmental exposure variables.
RESULTS—Mean (SD) blood, tibial, and patellar lead concentrations were 9.5 (4.5) µg/dl, 10.2 (10.1) µg Pb/g bone mineral, and 15.2 (15.1) µg Pb/g bone mineral respectively. These values are considerably higher than values for women in the United States. Older age, the cumulative use of lead glazed pottery, and higher proportion of life spent in Mexico City were powerful predictors of higher bone lead concentrations. Use of lead glazed ceramics to cook food in the past week and increased patellar lead concentrations were significant predictors of increased blood lead. Patellar lead concentrations explained one third of the variance accounted for by the final blood lead model. Women in the 90th percentile for patella lead had an untransformed predicted mean blood lead concentration 3.6 µg/dl higher than those in the 10th percentile.
CONCLUSIONS—This study identified the use of lead glazed ceramics as a major source of cumulative exposure to lead, as reflected by bone lead concentrations, as well as current exposure, reflected by blood lead, in Mexico. A higher proportion of life spent in Mexico City, a proxy for exposure to leaded gasoline emissions, was identified as the other major source of cumulative lead exposure. The influence of bone lead on blood lead coupled with the long half life of lead in bone has implications for other populations and suggests that bone stores may pose a threat to women of reproductive age long after exposure has declined.


Keywords: postpartum; blood lead; bone lead PMID:10896960

Neurodevelopment in Early Childhood Affected by Prenatal Lead Exposure and Iron Intake.

PubMed

Shah-Kulkarni, Surabhi; Ha, Mina; Kim, Byung-Mi; Kim, Eunjeong; Hong, Yun-Chul; Park, Hyesook; Kim, Yangho; Kim, Bung-Nyun; Chang, Namsoo; Oh, Se-Young; Kim, Young Ju; Kimʼs, Young Ju; Lee, Boeun; Ha, Eun-Hee

2016-01-01

No safe threshold level of lead exposure in children has been recognized. Also, the information on shielding effect of maternal dietary iron intake during pregnancy on the adverse effects of prenatal lead exposure on children's postnatal neurocognitive development is very limited. We examined the association of prenatal lead exposure and neurodevelopment in children at 6, 12, 24, and 36 months and the protective action of maternal dietary iron intake against the impact of lead exposure. The study participants comprise 965 pregnant women and their subsequent offspring of the total participants enrolled in the Mothers and Children's environmental health study: a prospective birth cohort study. Generalized linear model and linear mixed model analysis were performed to analyze the effect of prenatal lead exposure and mother's dietary iron intake on children's cognitive development at 6, 12, 24, and 36 months. Maternal late pregnancy lead was marginally associated with deficits in mental development index (MDI) of children at 6 months. Mothers having less than 75th percentile of dietary iron intake during pregnancy showed significant increase in the harmful effect of late pregnancy lead exposure on MDI at 6 months. Linear mixed model analyses showed the significant detrimental effect of prenatal lead exposure in late pregnancy on cognitive development up to 36 months in children of mothers having less dietary iron intake during pregnancy. Thus, our findings imply importance to reduce prenatal lead exposure and have adequate iron intake for better neurodevelopment in children.

Neurodevelopment in Early Childhood Affected by Prenatal Lead Exposure and Iron Intake

PubMed Central

Shah-Kulkarni, Surabhi; Ha, Mina; Kim, Byung-Mi; Kim, Eunjeong; Hong, Yun-Chul; Park, Hyesook; Kim, Yangho; Kim, Bung-Nyun; Chang, Namsoo; Oh, Se-Young; Kim, Young Ju; Lee, Boeun; Ha, Eun-Hee

2016-01-01

Abstract No safe threshold level of lead exposure in children has been recognized. Also, the information on shielding effect of maternal dietary iron intake during pregnancy on the adverse effects of prenatal lead exposure on children's postnatal neurocognitive development is very limited. We examined the association of prenatal lead exposure and neurodevelopment in children at 6, 12, 24, and 36 months and the protective action of maternal dietary iron intake against the impact of lead exposure. The study participants comprise 965 pregnant women and their subsequent offspring of the total participants enrolled in the Mothers and Children's environmental health study: a prospective birth cohort study. Generalized linear model and linear mixed model analysis were performed to analyze the effect of prenatal lead exposure and mother's dietary iron intake on children's cognitive development at 6, 12, 24, and 36 months. Maternal late pregnancy lead was marginally associated with deficits in mental development index (MDI) of children at 6 months. Mothers having less than 75th percentile of dietary iron intake during pregnancy showed significant increase in the harmful effect of late pregnancy lead exposure on MDI at 6 months. Linear mixed model analyses showed the significant detrimental effect of prenatal lead exposure in late pregnancy on cognitive development up to 36 months in children of mothers having less dietary iron intake during pregnancy. Thus, our findings imply importance to reduce prenatal lead exposure and have adequate iron intake for better neurodevelopment in children. PMID:26825887

Health impacts due to personal exposure to fine particles caused by insulation of residential buildings in Europe

NASA Astrophysics Data System (ADS)

Gens, Alexandra; Hurley, J. Fintan; Tuomisto, Jouni T.; Friedrich, Rainer

2014-02-01

The insulation of residential buildings affects human exposure to fine particles. According to current EU guidelines, insulation is regulated for energy saving reasons. As buildings become tighter, the air exchange rate is reduced and, thus, the indoor concentration of pollutants is increased if there are significant indoor sources. While usually the effects of heat insulation and increase of the air-tightness of buildings on greenhouse gas emissions are highlighted, the negative impacts on human health due to higher indoor concentrations are not addressed. Thus, we investigated these impacts using scenarios in three European countries, i. e. Czech Republic, Switzerland and Greece. The assessment was based on modelling the human exposure to fine particles originating from sources of particles within outdoor and indoor air, including environmental tobacco smoke. Exposure response relationships were derived to link (adverse) health effects to the exposure. Furthermore, probable values for the parameters influencing the infiltration of fine particles into residential buildings were modelled. Results show that the insulation and increase of the air-tightness of residential buildings leads to an overall increase of the mean population exposure - and consequently adverse health effects - in all considered countries (ranging for health effects from 0.4% in Czech Republic to 11.8% in Greece for 100% insulated buildings) due to an accumulation of particles indoors, especially from environmental tobacco smoke. Considering only the emission reductions in outdoor air (omitting changes in infiltration parameters) leads to a decrease of adverse health effects. This study highlights the importance of ensuring a sufficient air exchange rate when insulating buildings, e. g. by prescribing heat ventilation and air conditioning systems in new buildings and information campaigns on good airing practice in renovated buildings. It also shows that assessing policy measures based on the exposure may provide different recommendations compared to an assessment based on only the outdoor air concentration.

A Public Health Approach to Addressing Lead

EPA Pesticide Factsheets

Describes EPA’s achievements in reducing childhood lead exposures and emphasizes the need to continue actions to further reduce lead exposures, especially in those communities where exposures remain high.

EEG electrode caps can reduce SAR induced in the head by GSM900 mobile phones.

PubMed

Hamblin, Denise L; Anderson, Vitas; McIntosh, Robert L; McKenzie, Ray J; Wood, Andrew W; Iskra, Steve; Croft, Rodney J

2007-05-01

This paper investigates the influence of EEG electrode caps on specific absorption rate (SAR) in the head from a GSM900 mobile phone (217-Hz modulation, peak power output 2 W). SAR measurements were recorded in an anthropomorphic phantom using a precision robotic system. Peak 10 g average SAR in the whole head and in just the temporal region was compared for three phantom arrangements; no cap, 64-electrode "Electro-Cap," and 64-electrode "Quick-Cap". Relative to the "no cap" arrangement, the Electro-Cap and Quick-Cap caused a peak SAR (10 g) reduction of 14% and 18% respectively in both the whole head and in the temporal region. Additional computational modeling confirmed that SAR (10 g) is reduced by the presence of electrode leads and that the extent of the effect varies according to the orientation of the leads with respect to the radiofrequency (RF) source. The modeling also indicated that the nonconductive shell between the electrodes and simulated head material does not significantly alter the electrode lead shielding effect. The observed SAR reductions are not likely to be sufficiently large to have accounted for null EEG findings in the past but should nonetheless be noted in studies aiming to measure and report human brain activity under similar exposure conditions.

Quantitative assessment of human and pet exposure to Salmonella associated with dry pet foods.

PubMed

Lambertini, Elisabetta; Buchanan, Robert L; Narrod, Clare; Ford, Randall M; Baker, Robert C; Pradhan, Abani K

2016-01-04

Recent Salmonella outbreaks associated with dry pet foods and treats highlight the importance of these foods as previously overlooked exposure vehicles for both pets and humans. In the last decade efforts have been made to raise the safety of this class of products, for instance by upgrading production equipment, cleaning protocols, and finished product testing. However, no comprehensive or quantitative risk profile is available for pet foods, thus limiting the ability to establish safety standards and assess the effectiveness of current and proposed Salmonella control measures. This study sought to develop an ingredients-to-consumer quantitative microbial exposure assessment model to: 1) estimate pet and human exposure to Salmonella via dry pet food, and 2) assess the impact of industry and household-level mitigation strategies on exposure. Data on prevalence and concentration of Salmonella in pet food ingredients, production process parameters, bacterial ecology, and contact transfer in the household were obtained through literature review, industry data, and targeted research. A probabilistic Monte Carlo modeling framework was developed to simulate the production process and basic household exposure routes. Under the range of assumptions adopted in this model, human exposure due to handling pet food is null to minimal if contamination occurs exclusively before extrusion. Exposure increases considerably if recontamination occurs post-extrusion during coating with fat, although mean ingested doses remain modest even at high fat contamination levels, due to the low percent of fat in the finished product. Exposure is highly variable, with the distribution of doses ingested by adult pet owners spanning 3Log CFU per exposure event. Child exposure due to ingestion of 1g of pet food leads to significantly higher doses than adult doses associated with handling the food. Recontamination after extrusion and coating, e.g., via dust or equipment surfaces, may also lead to exposure due to the absence of pathogen reduction steps after extrusion or at consumer households. Exposure is potentially highest when Salmonella is transferred to human food that is left at growth-promoting conditions. This model can be applied to evaluate the impact of alternative Salmonella control measures during production, risk communication to consumers, and regulatory standards. Copyright © 2015 Elsevier B.V. All rights reserved.

Testing for lead in toys at day care centers.

PubMed

Sanders, Martha; Stolz, Julie; Chacon-Baker, Ashley

2013-01-01

Exposure to lead-based paint or material has been found to impact children's cognitive and behavioral development at blood lead levels far below current standards. The purpose of the project was to screen for lead in toy items in daycare centers in order to raise awareness of inside environmental lead exposures and minimize lead-based exposures for children. Occupational therapy students in a service learning class tested for lead in ten daycare or public centers using the XRF Thermo Scientific Niton XL3t, a method accepted by the Consumer Product Safety Commission (CPSC). A total of 460 items were tested over a two-month period for an average of 66 toys per setting. Fifty six (56) items tested > 100 ppm, which represented 12% of the entire sample. Items with high lead levels included selected toys constructed with lead-based paint, lead metals, plastics using lead as a color enhancer, and decorative objects. While the actual number of lead-based products is small, the cumulative exposure or habitual use may pose an unnecessary risk to children. Indoor exposures occurred for all day care centers regardless of socio-economic levels. Recommendations to minimize exposures are provided.

Childhood lead poisoning from commercially manufactured French ceramic dinnerware--New York City, 2003.

PubMed

2004-07-09

Lead poisoning adversely affects children worldwide. During 1999-2000, an estimated 434,000 children aged 1-5 years in the United States had elevated blood lead levels (BLLs) >/=10 microg/dL. Glazes found on ceramics, earthenware, bone china, and porcelain often contain lead and are a potential source of lead exposure. Children are especially vulnerable to the neurotoxic effects of lead. Exposures to lead in early childhood can have adverse effects on the developing nervous system, resulting in decreased intelligence and changes in behavior. In addition, certain behaviors (e.g., thumb sucking) place children at greater risk for exposure to lead. In 2003, the New York City Department of Health and Mental Hygiene's Lead Poisoning Prevention Program (LPPP), and the Mount Sinai Pediatric Environmental Health Specialty Unit (PEHSU) investigated a case of lead poisoning in a boy aged 20 months. This report summarizes that case investigation, which identified ceramic dinnerware imported from France as the source of lead exposure. This case underscores the susceptibility of children to a toxic exposure associated with 1) the high proportion of time spent in the home and 2) dietary habits that promote exposure to lead leached from ceramic ware.

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

PubMed

Akkus, Cem; Ozdenerol, Esra

2014-06-18

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

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

PubMed Central

Akkus, Cem; Ozdenerol, Esra

2014-01-01

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

Chronic lead exposure enhances the sympathoexcitatory response associated with P2X4 receptor in rat stellate ganglia.

PubMed

Zhu, Gaochun; Chen, Zhenying; Dai, Bo; Zheng, Chaoran; Jiang, Huaide; Xu, Yurong; Sheng, Xuan; Guo, Jingjing; Dan, Yu; Liang, Shangdong; Li, Guilin

2018-06-01

Chronic lead exposure causes peripheral sympathetic nerve stimulation, including increased blood pressure and heart rate. Purinergic receptors are involved in the sympathoexcitatory response induced by myocardial ischemia injury. However, whether P2X4 receptor participates in sympathoexcitatory response induced by chronic lead exposure and the possible mechanisms are still unknown. The aim of this study was to explore the change of the sympathoexcitatory response induced by chronic lead exposure via the P2X4 receptor in the stellate ganglion (SG). Rats were given lead acetate through drinking water freely at doses of 0 g/L (control group), 0.5 g/L (low lead group), and 2 g/L (high lead group) for 1 year. Our results demonstrated that lead exposure caused autonomic nervous dysfunction, including blood pressure and heart rate increased and heart rate variability (HRV) decreased. Western blotting results indicated that after lead exposure, the protein expression levels in the SG of P2X4 receptor, IL-1β and Cx43 were up-regulated, the phosphorylation of p38 mitogen-activated protein kinase (MAPK) was activated. Real-time PCR results showed that the mRNA expression of P2X4 receptor in the SG was higher in lead exposure group than that in the control group. Double-labeled immunofluorescence results showed that P2X4 receptor was co-expressed with glutamine synthetase (GS), the marker of satellite glial cells (SGCs). These changes were positively correlated with the dose of lead exposure. The up-regulated expression of P2X4 receptor in SGCs of the SG maybe enhance the sympathoexcitatory response induced by chronic lead exposure. © 2018 Wiley Periodicals, Inc.

Secondhand Smoke Exposure and Low Blood Lead Levels in Association With Attention-Deficit Hyperactivity Disorder and Its Symptom Domain in Children: A Community-Based Case–Control Study

PubMed Central

Joo, Hyunjoo; Lim, Myung-Ho; Kwon, Ho-Jang; Yoo, Seung Jin; Choi, Kyung-Hwa; Paik, Ki-Chung

2017-01-01

Aim: Secondhand smoke (SHS) is a major indoor pollutant. We examined the possible association between exposure to both SHS and low levels of lead and attention-deficit–hyperactivity disorder (ADHD) and its symptom domain in children. Methods: This case–control study was based on the results of a community survey using the ADHD rating scale conducted in 49 elementary schools. Both cases and control subjects were confirmed by a child psychiatrist. Each case was matched with one control subject according to gender, school, and grade in school. Using a multivariate conditional logistic regression model, we analyzed 214 case–control pairs of children who ranged in age from 6 to 10 years. Urine and blood levels of cotinine and of lead were determined, and information pertaining to SHS exposure was obtained by means of a questionnaire. Results: Exposure to low levels of lead (geometric mean = 1.65 µg/dL) was related to ADHD, particularly inattention (odds ratio [OR] = 1.67, 95% confidence interval [CI] = 1.07–2.59), whereas SHS exposure was associated mainly with hyperactivity/impulsivity (OR = 3.85, 95% CI = 1.55–9.56). In the pathway from blood lead to hyperactivity/impulsivity, children’s SHS exposure mediated and indirectly accounted for about 73% of this relationship. The combined exposure to lead and SHS synergistically increased the risk of ADHD, evident as both inattention and hyperactivity/impulsivity. Conclusion: SHS, which is associated with hyperactivity/impulsivity in particular, combined with exposure to low blood levels of lead synergistically increased the risk of ADHD. Therefore, the exposure of children to both SHS and lead needs to be reduced. Implications: Although exposure to low levels of lead has been shown to be associated with ADHD, there is little evidence of symptom domain specificity. In our study, low blood lead levels were related to inattention. In addition, prenatal or postnatal exposure to SHS increased the risk of ADHD, particularly hyperactivity/impulsivity. Combined exposure to lead and SHS synergistically increased the risk for both these ADHD symptom domains. To protect children from environmental risk factors related to ADHD, it is necessary to further reduce children’s exposure to SHS and lead, even in those with low blood lead levels. PMID:27613950

Secondhand Smoke Exposure and Low Blood Lead Levels in Association With Attention-Deficit Hyperactivity Disorder and Its Symptom Domain in Children: A Community-Based Case-Control Study.

PubMed

Joo, Hyunjoo; Lim, Myung-Ho; Ha, Mina; Kwon, Ho-Jang; Yoo, Seung Jin; Choi, Kyung-Hwa; Paik, Ki-Chung

2017-01-01

Secondhand smoke (SHS) is a major indoor pollutant. We examined the possible association between exposure to both SHS and low levels of lead and attention-deficit-hyperactivity disorder (ADHD) and its symptom domain in children. This case-control study was based on the results of a community survey using the ADHD rating scale conducted in 49 elementary schools. Both cases and control subjects were confirmed by a child psychiatrist. Each case was matched with one control subject according to gender, school, and grade in school. Using a multivariate conditional logistic regression model, we analyzed 214 case-control pairs of children who ranged in age from 6 to 10 years. Urine and blood levels of cotinine and of lead were determined, and information pertaining to SHS exposure was obtained by means of a questionnaire. Exposure to low levels of lead (geometric mean = 1.65 µg/dL) was related to ADHD, particularly inattention (odds ratio [OR] = 1.67, 95% confidence interval [CI] = 1.07-2.59), whereas SHS exposure was associated mainly with hyperactivity/impulsivity (OR = 3.85, 95% CI = 1.55-9.56). In the pathway from blood lead to hyperactivity/impulsivity, children's SHS exposure mediated and indirectly accounted for about 73% of this relationship. The combined exposure to lead and SHS synergistically increased the risk of ADHD, evident as both inattention and hyperactivity/impulsivity. SHS, which is associated with hyperactivity/impulsivity in particular, combined with exposure to low blood levels of lead synergistically increased the risk of ADHD. Therefore, the exposure of children to both SHS and lead needs to be reduced. Although exposure to low levels of lead has been shown to be associated with ADHD, there is little evidence of symptom domain specificity. In our study, low blood lead levels were related to inattention. In addition, prenatal or postnatal exposure to SHS increased the risk of ADHD, particularly hyperactivity/impulsivity. Combined exposure to lead and SHS synergistically increased the risk for both these ADHD symptom domains. To protect children from environmental risk factors related to ADHD, it is necessary to further reduce children's exposure to SHS and lead, even in those with low blood lead levels. © The Author 2016. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco.

[Lead exposure of people living in a lead high exposure area from local diet].

PubMed

Zhou, Yong; He, Liping; Huang, Xiao; He, Junshan

2011-11-01

To study the lead exposure of people living in a lead high exposure area from local diet, and to assess its health risks. Thirty five subjects were selected by random from a mining area and another 30 subjects were selected from a non-polluted area. The exposure of lead was estimated by the content of lead in drinking water and vegetables, and health risks was estimated by the levels of lead in blood and urine. The content of lead in drinking water and vegetables in the mining area was 20.6 microg/L and 1.61mg/kg (geometric mean) respectively, which were higher than that in the unpolluted area (6.0 microg/L and 0.56 mg/kg, geometric mean) (P < 0.01). The daily lead exposure of male and female inhabitants in the mining area from diet was 16.88 microg/kg and 16.09 microg/kg respectively, which was higher than that in the unpolluted area (P < 0.01), but the sex difference was not significant statistically (P > 0.05). Blood lead and urine lead of inhabitants in the mining-area were higher than those in the unpolluted area. The health risks for male and female inhabitants in the mining area were 4.73 and 4.51. The health risks of lead exposure caused by diet (drinking water and food) were relatively high in the mining area.

An experimental heat wave changes immune defense and life history traits in a freshwater snail.

PubMed

Leicht, Katja; Jokela, Jukka; Seppälä, Otto

2013-12-01

The predicted increase in frequency and severity of heat waves due to climate change is expected to alter disease dynamics by reducing hosts' ability to resist infections. This could take place via two different mechanisms: (1) through general reduction in hosts' performance under harsh environmental conditions and/or (2) through altered resource allocation that reduces expression of defense traits in order to maintain other traits. We tested these alternative hypotheses by measuring the effect of an experimental heat wave (25 vs. 15°C) on the constitutive level of immune defense (hemocyte concentration, phenoloxidase [PO]-like activity, antibacterial activity of hemolymph), and life history traits (growth and number of oviposited eggs) of the great pond snail Lymnaea stagnalis. We also manipulated the exposure time to high temperature (1, 3, 5, 7, 9, or 11 days). We found that if the exposure to high temperature lasted <1 week, immune function was not affected. However, when the exposure lasted longer than that, the level of snails' immune function (hemocyte concentration and PO-like activity) was reduced. Snails' growth and reproduction increased within the first week of exposure to high temperature. However, longer exposures did not lead to a further increase in cumulative reproductive output. Our results show that short experimental heat waves do not alter immune function but lead to plastic responses that increase snails' growth and reproduction. Thus, although the relative expression of traits changes, short experimental heat waves do not impair snails' defenses. Negative effects on performance get pronounced when the heat waves are prolonged suggesting that high performance cannot be maintained over long time periods. This ultimately reduces the levels of defense traits.

[Influence of extremely low frequency magnetic field on total protein and -sh groups concentrations in liver homogenates].

PubMed

Ciejka, Elżbieta; Kowalczyk, Agata; Gorąca, Anna

2014-01-01

Free radicals are atoms, molecules or their fragments, whose excess leads to the development of oxidative stress, the cause of many neoplastic, neurodegenerative and inflammatory diseases, as well as aging of organisms. Industrial pollution, tobacco smoke, ionizing radiation, ultrasound and magnetic fields are the major exogenous sources of free radicals. The low frequency mag- netic field is commonly applied in physiotherapy. The aim of the present study was to evaluate the effect of extremely low frequency magnetic field (1L.F-MF) on the concentration ofsullhydryl groups (-SH) and proteins in liver tissues of experimental animals de- pending on the time of exposure to the field. Twenty one Sprague-D)awley male rats, aged 3-4 months were randomly divided into 3 experimental groups (each containing 7 animals): controls (group I), the rats exposed to IEI.F-MF of 40 Hz, 7 mT (this kind of the ELF-MF is mostly used in magnetotherapy), 30 min/day for 2 weeks (group II) and the rats exposed to 40 Hz, 7 mT for 60 min/day for 2 weeks (group III). The concentrations of proteins and sulfhydryl groups in the liver tissues were determined after exposure to magnetic fields. Exposure to low magnetic field: 40 Hz, 7 mT for 30 min/day and 60 min/day for 2 weeks caused a significant increase in the concentration of-SH groups and total protein levels in the liver tissues. The study results suggest that exposure to magnetic fields leads to the development of adaptive mechanisms to maintain the balance in the body oxidation-reduction and in the case of the studied parameters does not depend on the time of exposure.

Health and household air pollution from solid fuel use: the need for improved exposure assessment.

PubMed

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

2013-10-01

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

Short-term exposure to 17alpha-ethynylestradiol decreases the fertility of sexually maturing male rainbow trout (Oncorhynchus mykiss)

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

Schultz, Irv R.; Skillman, Ann D.; Nicolas, Jean-Marc

The synthetic estrogen 17alpha-ethynylestradiol (EE2) is a commonly used oral contraceptive that has been increasingly detected in sewage effluents. This study determined whether EE2 exposure adversely affected reproduction in sexually maturing male rainbow trout (Oncorhynchus mykiss). We exposed male trout to graded water concentrations of EE2 (10, 100, and 1,000 ng/ L) for 62 d leading up to the time of spawning. Semen and blood plasma samples were removed from each fish. Semen was used to fertilize groups of eggs from one nonexposed female. As a measure of fertility, eggs were incubated for 28 d after fertilization to determine themore » proportion that attained the eyed stage of embryonic development. Additional endpoints also measured included sperm motility, spermatocrit, gonadosomatic and hepatosomatic indices, testis histology, and circulating plasma levels of the sex steroids 17alpha, 20beta-dihydroxyprogesterone (17,20-DHP) and 11-ketotestosterone (11-KT). Exposure to 1,000 ng/L of EE2 caused complete mortality of the treatment group by day 57. Exposure to lower EE2 water concentrations (10 and 100 ng/L) caused an increase in sperm density, while a significant reduction in testis mass was observed only in the 100-ng/L exposure group. Most significantly, semen harvested from fish exposed to 10 and 100 ng/L EE2 caused an approximately 50% reduction in the number of eggs attaining the eyed stage of embryonic development. Plasma levels of 17,20-DHP in exposed fish were roughly twice the level of the controls, while levels of 11-KT were significantly reduced in fish exposed to 100 ng/L EE2. These results suggest that sexually maturing male rainbow trout are susceptible to detrimental reproductive effects of short-term exposures to environmentally relevant levels of EE2.« less

Short-term exposure to 17 alpha-ethynylestradiol decreases the fertility of sexually maturing male rainbow trout (Oncorhynchus mykiss).

PubMed

Schultz, Irvin R; Skillman, Ann; Nicolas, Jean-Marc; Cyr, Daniel G; Nagler, James J

2003-06-01

The synthetic estrogen 17 alpha-ethynylestradiol (EE2) is a commonly used oral contraceptive that has been increasingly detected in sewage effluents. This study determined whether EE2 exposure adversely affected reproduction in sexually maturing male rainbow trout (Oncorhynchus mykiss). We exposed male trout to graded water concentrations of EE2 (10, 100, and 1,000 ng/ L) for 62 d leading up to the time of spawning. Semen and blood plasma samples were removed from each fish. Semen was used to fertilize groups of eggs from one nonexposed female. As a measure of fertility, eggs were incubated for 28 d after fertilization to determine the proportion that attained the eyed stage of embryonic development. Additional endpoints also measured included sperm motility, spermatocrit, gonadosomatic and hepatosomatic indices, testis histology, and circulating plasma levels of the sex steroids 17 alpha, 20 beta-dihydroxyprogesterone (17,20-DHP) and 11-ketotestosterone (11-KT). Exposure to 1,000 ng/L of EE2 caused complete mortality of the treatment group by day 57. Exposure to lower EE2 water concentrations (10 and 100 ng/L) caused an increase in sperm density, while a significant reduction in testis mass was observed only in the 100-ng/L exposure group. Most significantly, semen harvested from fish exposed to 10 and 100 ng/L EE2 caused an approximately 50% reduction in the number of eggs attaining the eyed stage of embryonic development. Plasma levels of 17,20-DHP in exposed fish were roughly twice the level of the controls, while levels of 11-KT were significantly reduced in fish exposed to 100 ng/L EE2. These results suggest that sexually maturing male rainbow trout are susceptible to detrimental reproductive effects of short-term exposures to environmentally relevant levels of EE2.

Pb Neurotoxicity: Neuropsychological Effects of Lead Toxicity

PubMed Central

Mason, Lisa H.; Harp, Jordan P.; Han, Dong Y.

2014-01-01

Neurotoxicity is a term used to describe neurophysiological changes caused by exposure to toxic agents. Such exposure can result in neurocognitive symptoms and/or psychiatric disturbances. Common toxic agents include heavy metals, drugs, organophosphates, bacterial, and animal neurotoxins. Among heavy metal exposures, lead exposure is one of the most common exposures that can lead to significant neuropsychological and functional decline in humans. In this review, neurotoxic lead exposure's pathophysiology, etiology, and epidemiology are explored. In addition, commonly associated neuropsychological difficulties in intelligence, memory, executive functioning, attention, processing speed, language, visuospatial skills, motor skills, and affect/mood are explored. PMID:24516855

Human health risk assessment of lead from mining activities at semi-arid locations in the context of total lead exposure.

PubMed

Zheng, Jiajia; Huynh, Trang; Gasparon, Massimo; Ng, Jack; Noller, Barry

2013-12-01

Lead from historical mining and mineral processing activities may pose potential human health risks if materials with high concentrations of bioavailable lead minerals are released to the environment. Since the Joint Expert Committee on Food Additives of Food and Agriculture Organization/World Health Organization withdrew the Provisional Tolerable Weekly Intake of lead in 2011, an alternative method was required for lead exposure assessment. This study evaluated the potential lead hazard to young children (0-7 years) from a historical mining location at a semi-arid area using the U.S. EPA Integrated Exposure Uptake Biokinetic (IEUBK) Model, with selected site-specific input data. This study assessed lead exposure via the inhalation pathway for children living in a location affected by lead mining activities and with specific reference to semi-arid conditions and made comparison with the ingestion pathway by using the physiologically based extraction test for gastro-intestinal simulation. Sensitivity analysis for major IEUBK input parameters was conducted. Three groups of input parameters were classified according to the results of predicted blood concentrations. The modelled lead absorption attributed to the inhalation route was lower than 2 % (mean ± SE, 0.9 % ± 0.1 %) of all lead intake routes and was demonstrated as a less significant exposure pathway to children's blood, compared with ingestion. Whilst dermal exposure was negligible, diet and ingestion of soil and dust were the dominant parameters in terms of children's blood lead prediction. The exposure assessment identified the changing role of dietary intake when house lead loadings varied. Recommendations were also made to conduct comprehensive site-specific human health risk assessment in future studies of lead exposure under a semi-arid climate.

Combined exposure to cyanobacterial biomass, lead and the Newcastle virus enhances avian toxicity.

PubMed

Pikula, Jiri; Bandouchova, Hana; Hilscherova, Klara; Paskova, Veronika; Sedlackova, Jana; Adamovsky, Ondrej; Knotkova, Zora; Lany, Petr; Machat, Jiri; Marsalek, Blahoslav; Novotny, Ladislav; Pohanka, Miroslav; Vitula, Frantisek

2010-10-01

Under environmental conditions, wild birds can be exposed to multiple stressors including natural toxins, anthropogenic pollutants and infectious agents at the same time. This experimental study was successful in testing the hypothesis that adverse effects of cyanotoxins, heavy metals and a non-pathogenic immunological challenge combine to enhance avian toxicity. Mortality occurred in combined exposures to naturally occurring cyanobacterial biomass and lead shots, lead shots and Newcastle vaccination as well as in single lead shot exposure. Mostly acute effects around day 10 were observed. On day 30 of exposure, there were no differences in the liver accumulation of lead in single and combined exposure groups. Interestingly, liver microcystin levels were elevated in birds co-exposed to cyanobacterial biomass together with lead or lead and the Newcastle virus. Significant differences in body weights between all Pb-exposed and Pb-non-exposed birds were found on days 10 and 20. Single exposure to cyanobacterial biomass resulted in hepatic vacuolar dystrophy, whereas co-exposure with lead led to more severe granular dystrophy. Haematological changes were associated with lead exposure, in particular. Biochemical analysis revealed a decrease in glucose and an increase in lactate dehydrogenase in single and combined cyanobacterial and lead exposures, which also showed a decreased antibody response to vaccination. The combined exposure of experimental birds to sub-lethal doses of individual stressors is ecologically realistic. It brings together new pieces of knowledge on avian health. In light of this study, investigators of wild bird die-offs should be circumspect when evaluating findings of low concentrations of contaminants that would not result in mortality on a separate basis. As such it has implications for wildlife biologists, veterinarians and conservationists of avian biodiversity. Copyright 2010 Elsevier B.V. All rights reserved.

Evidence that ship noise increases stress in right whales

PubMed Central

Rolland, Rosalind M.; Parks, Susan E.; Hunt, Kathleen E.; Castellote, Manuel; Corkeron, Peter J.; Nowacek, Douglas P.; Wasser, Samuel K.; Kraus, Scott D.

2012-01-01

Baleen whales (Mysticeti) communicate using low-frequency acoustic signals. These long-wavelength sounds can be detected over hundreds of kilometres, potentially allowing contact over large distances. Low-frequency noise from large ships (20–200 Hz) overlaps acoustic signals used by baleen whales, and increased levels of underwater noise have been documented in areas with high shipping traffic. Reported responses of whales to increased noise include: habitat displacement, behavioural changes and alterations in the intensity, frequency and intervals of calls. However, it has been unclear whether exposure to noise results in physiological responses that may lead to significant consequences for individuals or populations. Here, we show that reduced ship traffic in the Bay of Fundy, Canada, following the events of 11 September 2001, resulted in a 6 dB decrease in underwater noise with a significant reduction below 150 Hz. This noise reduction was associated with decreased baseline levels of stress-related faecal hormone metabolites (glucocorticoids) in North Atlantic right whales (Eubalaena glacialis). This is the first evidence that exposure to low-frequency ship noise may be associated with chronic stress in whales, and has implications for all baleen whales in heavy ship traffic areas, and for recovery of this endangered right whale population. PMID:22319129

Evidence that ship noise increases stress in right whales.

PubMed

Rolland, Rosalind M; Parks, Susan E; Hunt, Kathleen E; Castellote, Manuel; Corkeron, Peter J; Nowacek, Douglas P; Wasser, Samuel K; Kraus, Scott D

2012-06-22

Baleen whales (Mysticeti) communicate using low-frequency acoustic signals. These long-wavelength sounds can be detected over hundreds of kilometres, potentially allowing contact over large distances. Low-frequency noise from large ships (20-200 Hz) overlaps acoustic signals used by baleen whales, and increased levels of underwater noise have been documented in areas with high shipping traffic. Reported responses of whales to increased noise include: habitat displacement, behavioural changes and alterations in the intensity, frequency and intervals of calls. However, it has been unclear whether exposure to noise results in physiological responses that may lead to significant consequences for individuals or populations. Here, we show that reduced ship traffic in the Bay of Fundy, Canada, following the events of 11 September 2001, resulted in a 6 dB decrease in underwater noise with a significant reduction below 150 Hz. This noise reduction was associated with decreased baseline levels of stress-related faecal hormone metabolites (glucocorticoids) in North Atlantic right whales (Eubalaena glacialis). This is the first evidence that exposure to low-frequency ship noise may be associated with chronic stress in whales, and has implications for all baleen whales in heavy ship traffic areas, and for recovery of this endangered right whale population.

Behavior of deuterium retention and surface morphology for VPS–W/F82H

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

Yasuhisa Oya; Masashi Shimada; Tomonori Tokunaga

The deuterium (D) retention for Vacuum Plasma Spray (VPS)–tungsten (W)/F82H was studied using two different implantation methods, namely D plasma exposure and View the MathML source implantation. The D retention for polished VPS–W/F82H after plasma exposure was found to be reduced compared to that for polycrystalline tungsten. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations indicated that porous structures around grain boundaries and the interface between VPS–W layers would be potential D diffusion paths, leading to low D retention. In the case of View the MathML source implantation, the shape of D2 TDS spectrum was almost the samemore » as that for D plasma-exposed VPS–W/F82H; however, the D retention was quite high for unpolished VPS–W/F82H, indicating that most of D was trapped by the oxide layer, which was produced by the VPS process. The reduction of surface area due to the polishing process also reduces D retention for VPS–W/F82H. These results indicate that controlling the surface chemical states is important for the reduction of tritium retention for future fusion reactors.« less

Occupational and environmental lead exposure in Port Harcourt, Nigeria: analysis of its association with renal function indices.

PubMed

Alasia, D D; Emem-Chioma, P C; Wokoma, F S

2010-01-01

In spite of the high risk of lead exposure in Nigeria, there is a paucity of data on the occupational and environmental burden of lead exposure and its impact on human health especially its nephrotoxic effects. This study aims to assess the degree of occupational and environmental lead exposure in Port Harcourt Nigeria and the relationship between lead exposure and indices of renal function. A cross sectional comparative study of 190 aduIt subjects with occupational lead exposure and 80 matched controls. Blood lead was used as the biomarker of lead exposure. Serum urea, creatinine, uric acid, urine albumin and glomerular filtration rate were the renal function indices measured. Occupationally lead exposed subjects had higher mean blood lead 50.37 +/- 24.58 ug/dI, than controls 41.40 +/- 26.85 ug/dl (p = 0.008). The mean values of serum urea, creatinine and uric acid were significantly higher in study subjects compared to controls 3.06 +/- 0.81 mmol/L vs. 2.7 +/- 0.84 mmol/L (p = 0.002), 87.2 +/- 14.30 umol/L vs. 80.68 +/- 14.70 umol/L (p = 0.001) and 271.93 +/- 71.18 umol/L vs. 231.1 +/- 62.70 umol/L (p = 0.000) respectively. Creatinine clearance was significantly lower in subjects compared to controls 98.86 +/- 21.26 mI/min/1.72m2 vs. 108.18 +/- 25.16 mI/min/1.72m2 (p = 0.002). Blood lead correlated positively only with blood urea [r = .031, r2 = .017, p = .031] and negatively [r = -.144, r2 = .02 1, p = .018] with serum phosphate. The level of environmental and occupational lead exposure in Port Harcourt, Nigeria is high, with occupational lead exposure increasing the risk of lead toxicity and renal function impairment.

Stressed to death: implication of lymphocyte apoptosis for psychoneuroimmunology

NASA Technical Reports Server (NTRS)

Shi, Yufang; Devadas, Satish; Greeneltch, Kristy M.; Yin, Deling; Allan Mufson, R.; Zhou, Jian-nian

2003-01-01

Psychological and physical stressors best exemplify the intercommunication of the immune and the nervous systems. It has been shown that stress significantly impacts leukocyte cellularity and immune responses and alters susceptibility to various diseases. While acute stress has been shown to enhance immune responses, chronic stress often leads to immunosuppression. Among many criteria examined upon exposure to chronic stress, the reduction in lymphocyte mitogenic response and lymphocyte cellularity are commonly assessed. We have reported that chronic restraint stress could induce lymphocyte reduction, an effect dependent on endogenous opioids. Interestingly, the effect of endogenous opioids was found to be exerted through increasing the expression of a cell death receptor, Fas, and an increased sensitivity of lymphocytes to apoptosis. Stress-induced lymphocyte reduction was not affected by adrenalectomy. In this review, based on available literature and our recent data, we will discuss the role of the hypothalamic-pituitary-adrenal axis and endogenous opioids and examine the mechanisms by which chronic stress modulates lymphocyte apoptosis.

A comparison of the diminution rates of lead in blood and lead mobilized by CaEDTA after termination of occupational exposure: a long-term observation in two lead workers.

PubMed

Araki, S; Murata, K; Aono, H; Yanagihara, S; Ushio, K

1983-07-01

CaEDTA 20 mg/kg was administered weekly for 3.5 years after termination of occupational exposure to two lead workers. The diminution half-lives for lead in blood and urine lead mobilized by CaEDTA were 4.8 and 3.3 years respectively for subject 1 following 28 years exposure and 3.3 and 2.0 years respectively for subject 2 following 26 years exposure. The difference in the diminution rate between lead in blood and lead mobilized by CaEDTA was significant in subject 2 (p less than 0.05).

Multi-Omics Reveals that Lead Exposure Disturbs Gut Microbiome Development, Key Metabolites, and Metabolic Pathways.

PubMed

Gao, Bei; Chi, Liang; Mahbub, Ridwan; Bian, Xiaoming; Tu, Pengcheng; Ru, Hongyu; Lu, Kun

2017-04-17

Lead exposure remains a global public health issue, and the recent Flint water crisis has renewed public concern about lead toxicity. The toxicity of lead has been well established in a variety of systems and organs. The gut microbiome has been shown to be highly involved in many critical physiological processes, including food digestion, immune system development, and metabolic homeostasis. However, despite the key role of the gut microbiome in human health, the functional impact of lead exposure on the gut microbiome has not been studied. The aim of this study is to define gut microbiome toxicity induced by lead exposure in C57BL/6 mice using multiomics approaches, including 16S rRNA sequencing, whole genome metagenomics sequencing, and gas chromatography-mass spectrometry (GC-MS) metabolomics. 16S rRNA sequencing revealed that lead exposure altered the gut microbiome trajectory and phylogenetic diversity. Metagenomics sequencing and metabolomics profiling showed that numerous metabolic pathways, including vitamin E, bile acids, nitrogen metabolism, energy metabolism, oxidative stress, and the defense/detoxification mechanism, were significantly disturbed by lead exposure. These perturbed molecules and pathways may have important implications for lead toxicity in the host. Taken together, these results demonstrated that lead exposure not only altered the gut microbiome community structures/diversity but also greatly affected metabolic functions, leading to gut microbiome toxicity.

MAPK pathway activation by chronic lead-exposure increases vascular reactivity through oxidative stress/cyclooxygenase-2-dependent pathways

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

Simões, Maylla Ronacher, E-mail: yllars@hotmail.com; Department of Pharmacology, Universidad Autonoma de Madrid, Instituto de Investigación Hospital Universitario La Paz; Aguado, Andrea

Chronic exposure to low lead concentration produces hypertension; however, the underlying mechanisms remain unclear. We analyzed the role of oxidative stress, cyclooxygenase-2-dependent pathways and MAPK in the vascular alterations induced by chronic lead exposure. Aortas from lead-treated Wistar rats (1st dose: 10 μg/100 g; subsequent doses: 0.125 μg/100 g, intramuscular, 30 days) and cultured aortic vascular smooth muscle cells (VSMCs) from Sprague Dawley rats stimulated with lead (20 μg/dL) were used. Lead blood levels of treated rats attained 21.7 ± 2.38 μg/dL. Lead exposure increased systolic blood pressure and aortic ring contractile response to phenylephrine, reduced acetylcholine-induced relaxation and didmore » not affect sodium nitroprusside relaxation. Endothelium removal and L-NAME left-shifted the response to phenylephrine more in untreated than in lead-treated rats. Apocynin and indomethacin decreased more the response to phenylephrine in treated than in untreated rats. Aortic protein expression of gp91(phox), Cu/Zn-SOD, Mn-SOD and COX-2 increased after lead exposure. In cultured VSMCs lead 1) increased superoxide anion production, NADPH oxidase activity and gene and/or protein levels of NOX-1, NOX-4, Mn-SOD, EC-SOD and COX-2 and 2) activated ERK1/2 and p38 MAPK. Both antioxidants and COX-2 inhibitors normalized superoxide anion production, NADPH oxidase activity and mRNA levels of NOX-1, NOX-4 and COX-2. Blockade of the ERK1/2 and p38 signaling pathways abolished lead-induced NOX-1, NOX-4 and COX-2 expression. Results show that lead activation of the MAPK signaling pathways activates inflammatory proteins such as NADPH oxidase and COX-2, suggesting a reciprocal interplay and contribution to vascular dysfunction as an underlying mechanisms for lead-induced hypertension. - Highlights: • Lead-exposure increases oxidative stress, COX-2 expression and vascular reactivity. • Lead exposure activates MAPK signaling pathway. • ROS and COX-2 activation by MAPK in lead exposure • Relationship between vascular ROS and COX-2 products in lead exposure.« less

Fixed, low radiant exposure vs. incremental radiant exposure approach for diode laser hair reduction: a randomized, split axilla, comparative single-blinded trial.

PubMed

Pavlović, M D; Adamič, M; Nenadić, D

2015-12-01

Diode lasers are the most commonly used treatment modalities for unwanted hair reduction. Only a few controlled clinical trials but not a single randomized controlled trial (RCT) compared the impact of various laser parameters, especially radiant exposure, onto efficacy, tolerability and safety of laser hair reduction. To compare the safety, tolerability and mid-term efficacy of fixed, low and incremental radiant exposures of diode lasers (800 nm) for axillary hair removal, we conducted an intrapatient, left-to-right, patient- and assessor-blinded and controlled trial. Diode laser (800 nm) treatments were evaluated in 39 study participants (skin type II-III) with unwanted axillary hairs. Randomization and allocation to split axilla treatments were carried out by a web-based randomization tool. Six treatments were performed at 4- to 6-week intervals with study subjects blinded to the type of treatment. Final assessment of hair reduction was conducted 6 months after the last treatment by means of blinded 4-point clinical scale using photographs. The primary endpoint was reduction in hair growth, and secondary endpoints were patient-rated tolerability and satisfaction with the treatment, treatment-related pain and adverse effects. Excellent reduction in axillary hairs (≥ 76%) at 6-month follow-up visit after receiving fixed, low and incremental radiant exposure diode laser treatments was obtained in 59% and 67% of study participants respectively (Z value: 1.342, P = 0.180). Patients reported lower visual analogue scale (VAS) pain score on the fixed (4.26) than on the incremental radiant exposure side (5.64) (P < 0.0003). The only side-effect was mild and transient erythema. Subjects better tolerated the fixed, low radiant exposure protocol (P = 0.03). The majority of the study participants were satisfied with both treatments. Both low and incremental radiant exposures produced similar hair reduction and high and comparable patient satisfaction. However, low radiant exposure diode laser treatments were less painful and better tolerated. © 2015 European Academy of Dermatology and Venereology.

Cholinergic aspects of cyanide intoxication

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

Von Bredow, J.D.; Vick, J.A.

1993-05-13

The acute exposure of pentobarbital anesthetized dogs to cyanide leads to a rapid increase and sudden halt in respiration accompanied by cardiovascular irregularities and extreme bradycardia which ultimately lead to cardiac arrest and death. Cardiac irregularities and cardiac arrest in the presence of cyanide induced respiratory arrest are assumed to be due to anoxia and therefore unresponsive to cardiotonic agents. Pretreatment or treatment with atropine sulfate or methyl atropine nitrate provides a marked reduction in the cardiovascular irregularities, bradycardia and hypotension. The cyanide induced cardiovascular effect can also be prevented by bilateral vagotomy. An intramuscularly injected combination of 20 mg/kgmore » sodium nitrite and 1 mg/kg of atropine sulfate ensured recovery of pentobarbital anesthetized dogs exposed to lethal concentrations (2.5 mg/kg i.v.) of sodium cyanide.« less

Dual role of the six-coordinated molybdenum and lead ions in novel of photochromic properties of the molybdenum-lead-borate glasses.

PubMed

Rada, M; Maties, V; Culea, M; Rada, S; Culea, E

2010-02-01

Transparent glasses were prepared by conventional melting-quenching method in the xMoO(3).(100-x)[3B(2)O(3).PbO] system where 0

Lead exposure in adult males in urban Transvaal Province, South Africa during the apartheid era.

PubMed

Hess, Catherine A; Cooper, Matthew J; Smith, Martin J; Trueman, Clive N; Schutkowski, Holger

2013-01-01

Human exposure to lead is a substantial public health hazard worldwide and is particularly problematic in the Republic of South Africa given the country's late cessation of leaded petrol. Lead exposure is associated with a number of serious health issues and diseases including developmental and cognitive deficiency, hypertension and heart disease. Understanding the distribution of lifetime lead burden within a given population is critical for reducing exposure rates. Femoral bone from 101 deceased adult males living in urban Transvaal Province (now Gauteng Province), South Africa between 1960 and 1998 were analyzed for lead concentration by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Of the 72 black and 29 white individuals sampled, chronic lead exposure was apparent in nearly all individuals. White males showed significantly higher median bone lead concentration (ME = 10.04 µg·g(-1)), than black males (ME = 3.80 µg·g(-1)) despite higher socioeconomic status. Bone lead concentration covaries significantly, though weakly, with individual age. There was no significant temporal trend in bone lead concentration. These results indicate that long-term low to moderate lead exposure is the historical norm among South African males. Unexpectedly, this research indicates that white males in the sample population were more highly exposed to lead.

Implications of new data on lead toxicity for managing and preventing exposure.

PubMed Central

Silbergeld, E K

1990-01-01

Recent advances in research on low-level lead poisoning point to the need to increase efforts to prevent exposure. Current biomedical consensus accepts that blood lead levels as low as 5 to 15 mcg/dL are risky to fetuses, young children, and adults. Lead at low dose is associated with increased blood pressure in adults, and chronic exposure has been associated in cohort studies with kidney disease and cancer. Data on lead toxicokinetics also points to the hazards of low-level, chronic exposure, since the lead that is accumulated over time in bone can be released at a relatively rapid rate during pregnancy and menopause. Sources that contribute to current lead exposure of the general population include unabated lead-based paint and contaminated soils, as well as lower level but pervasive sources in drinking water, food, and consumer products. PMID:2088754

Implications of new data on lead toxicity for managing and preventing exposure

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

Silbergeld, E.K.

1990-11-01

Recent advances in research on low-level lead poisoning point to the need to increase efforts to prevent exposure. Current biomedical consensus accepts that blood lead levels as low as 5 to 15 mcg/dL are risky to fetuses, young children, and adults. Lead at low dose is associated with increased blood pressure in adults, and chronic exposure has been associated in cohort studies with kidney disease and cancer. Data on lead toxicokinetics also points to the hazards of low-level, chronic exposure, since the lead that is accumulated over time in bone can be released at a relatively rapid rate during pregnancymore » and menopause. Sources that contribute to current lead exposure of the general population include unabated lead-based paint and contaminated soils, as well as lower level but pervasive sources in drinking water, food, and consumer products.« less

Lead Exposure in Free-Flying Turkey Vultures Is Associated with Big Game Hunting in California

PubMed Central

Kelly, Terra R.; Johnson, Christine K.

2011-01-01

Predatory and scavenging birds are at risk of lead exposure when they feed on animals injured or killed by lead ammunition. While lead ammunition has been banned from waterfowl hunting in North America for almost two decades, lead ammunition is still widely used for hunting big game and small game animals. In this study, we evaluated the association between big game hunting and blood lead concentration in an avian scavenger species that feeds regularly on large mammals in California. We compared blood lead concentration in turkey vultures within and outside of the deer hunting season, and in areas with varying wild pig hunting intensity. Lead exposure in turkey vultures was significantly higher during the deer hunting season compared to the off-season, and blood lead concentration was positively correlated with increasing wild pig hunting intensity. Our results link lead exposure in turkey vultures to deer and wild pig hunting activity at these study sites, and we provide evidence that spent lead ammunition in carrion poses a significant risk of lead exposure to scavengers. PMID:21494326

Lead exposure in free-flying turkey vultures is associated with big game hunting in California.

PubMed

Kelly, Terra R; Johnson, Christine K

2011-04-06

Predatory and scavenging birds are at risk of lead exposure when they feed on animals injured or killed by lead ammunition. While lead ammunition has been banned from waterfowl hunting in North America for almost two decades, lead ammunition is still widely used for hunting big game and small game animals. In this study, we evaluated the association between big game hunting and blood lead concentration in an avian scavenger species that feeds regularly on large mammals in California. We compared blood lead concentration in turkey vultures within and outside of the deer hunting season, and in areas with varying wild pig hunting intensity. Lead exposure in turkey vultures was significantly higher during the deer hunting season compared to the off-season, and blood lead concentration was positively correlated with increasing wild pig hunting intensity. Our results link lead exposure in turkey vultures to deer and wild pig hunting activity at these study sites, and we provide evidence that spent lead ammunition in carrion poses a significant risk of lead exposure to scavengers.

Latent variable models for gene-environment interactions in longitudinal studies with multiple correlated exposures.

PubMed

Tao, Yebin; Sánchez, Brisa N; Mukherjee, Bhramar

2015-03-30

Many existing cohort studies designed to investigate health effects of environmental exposures also collect data on genetic markers. The Early Life Exposures in Mexico to Environmental Toxicants project, for instance, has been genotyping single nucleotide polymorphisms on candidate genes involved in mental and nutrient metabolism and also in potentially shared metabolic pathways with the environmental exposures. Given the longitudinal nature of these cohort studies, rich exposure and outcome data are available to address novel questions regarding gene-environment interaction (G × E). Latent variable (LV) models have been effectively used for dimension reduction, helping with multiple testing and multicollinearity issues in the presence of correlated multivariate exposures and outcomes. In this paper, we first propose a modeling strategy, based on LV models, to examine the association between repeated outcome measures (e.g., child weight) and a set of correlated exposure biomarkers (e.g., prenatal lead exposure). We then construct novel tests for G × E effects within the LV framework to examine effect modification of outcome-exposure association by genetic factors (e.g., the hemochromatosis gene). We consider two scenarios: one allowing dependence of the LV models on genes and the other assuming independence between the LV models and genes. We combine the two sets of estimates by shrinkage estimation to trade off bias and efficiency in a data-adaptive way. Using simulations, we evaluate the properties of the shrinkage estimates, and in particular, we demonstrate the need for this data-adaptive shrinkage given repeated outcome measures, exposure measures possibly repeated and time-varying gene-environment association. Copyright © 2014 John Wiley & Sons, Ltd.

Research Review: Environmental exposures, neurodevelopment and child mental health – new paradigms for the study of brain and behavioral effects

PubMed Central

Rauh, Virginia A.; Margolis, Amy

2016-01-01

Background Environmental exposures play a critical role in the genesis of some child mental health problems. Methods We open with a discussion of children’s vulnerability to neurotoxic substances, changes in the distribution of toxic exposures, and co-occurrence of social and physical exposures. We address trends in prevalence of mental health disorders, and approaches to the definition of disorders that are sensitive to the subtle effects of toxic exposures. We suggest broadening outcomes to include dimensional measures of autism spectrum disorders, attention deficit hyperactivity disorder, and child learning capacity, as well as direct assessment of brain function. Findings We consider the impact of two important exposures on children’s mental health: lead and pesticides. We argue that longitudinal research designs may capture the cascading effects of exposures across biological systems and the full-range of neuropsychological endpoints. Neuroimaging is a valuable tool for observing brain maturation under varying environmental conditions. A dimensional approach to measurement may be sensitive to subtle sub-clinical toxic effects, permitting the development of exposure-related profiles and testing of complex functional relationships between brain and behavior. Questions about the neurotoxic effects of chemicals become more pressing when viewed through the lens of environmental justice. Conclusions Reduction in the burden of child mental health disorders will require longitudinal study of neurotoxic exposures, incorporating dimensional approaches to outcome assessment and measures of brain function. Research that seeks to identify links between toxic exposures and mental health outcomes has enormous public health and societal value. PMID:26987761

Research Review: Environmental exposures, neurodevelopment, and child mental health - new paradigms for the study of brain and behavioral effects.

PubMed

Rauh, Virginia A; Margolis, Amy E

2016-07-01

Environmental exposures play a critical role in the genesis of some child mental health problems. We open with a discussion of children's vulnerability to neurotoxic substances, changes in the distribution of toxic exposures, and cooccurrence of social and physical exposures. We address trends in prevalence of mental health disorders, and approaches to the definition of disorders that are sensitive to the subtle effects of toxic exposures. We suggest broadening outcomes to include dimensional measures of autism spectrum disorders, attention-deficit hyperactivity disorder, and child learning capacity, as well as direct assessment of brain function. We consider the impact of two important exposures on children's mental health: lead and pesticides. We argue that longitudinal research designs may capture the cascading effects of exposures across biological systems and the full-range of neuropsychological endpoints. Neuroimaging is a valuable tool for observing brain maturation under varying environmental conditions. A dimensional approach to measurement may be sensitive to subtle subclinical toxic effects, permitting the development of exposure-related profiles and testing of complex functional relationships between brain and behavior. Questions about the neurotoxic effects of chemicals become more pressing when viewed through the lens of environmental justice. Reduction in the burden of child mental health disorders will require longitudinal study of neurotoxic exposures, incorporating dimensional approaches to outcome assessment, and measures of brain function. Research that seeks to identify links between toxic exposures and mental health outcomes has enormous public health and societal value. © 2016 Association for Child and Adolescent Mental Health.

Lead Exposures in U.S. Children, 2008: Implications for Prevention

PubMed Central

Levin, Ronnie; Brown, Mary Jean; Kashtock, Michael E.; Jacobs, David E.; Whelan, Elizabeth A.; Rodman, Joanne; Schock, Michael R.; Padilla, Alma; Sinks, Thomas

2008-01-01

Objective We reviewed the sources of lead in the environments of U.S. children, contributions to children’s blood lead levels, source elimination and control efforts, and existing federal authorities. Our context is the U.S. public health goal to eliminate pediatric elevated blood lead levels (EBLs) by 2010. Data sources National, state, and local exposure assessments over the past half century have identified risk factors for EBLs among U.S. children, including age, race, income, age and location of housing, parental occupation, and season. Data extraction and synthesis Recent national policies have greatly reduced lead exposure among U.S. children, but even very low exposure levels compromise children’s later intellectual development and lifetime achievement. No threshold for these effects has been demonstrated. Although lead paint and dust may still account for up to 70% of EBLs in U.S. children, the U.S. Centers for Disease Control and Prevention estimates that ≥30% of current EBLs do not have an immediate lead paint source, and numerous studies indicate that lead exposures result from multiple sources. EBLs and even deaths have been associated with inadequately controlled sources including ethnic remedies and goods, consumer products, and food-related items such as ceramics. Lead in public drinking water and in older urban centers remain exposure sources in many areas. Conclusions Achieving the 2010 goal requires maintaining current efforts, especially programs addressing lead paint, while developing interventions that prevent exposure before children are poisoned. It also requires active collaboration across all levels of government to identify and control all potential sources of lead exposure, as well as primary prevention. PMID:18941567

Lead exposures in U.S. Children, 2008: implications for prevention.

PubMed

Levin, Ronnie; Brown, Mary Jean; Kashtock, Michael E; Jacobs, David E; Whelan, Elizabeth A; Rodman, Joanne; Schock, Michael R; Padilla, Alma; Sinks, Thomas

2008-10-01

We reviewed the sources of lead in the environments of U.S. children, contributions to children's blood lead levels, source elimination and control efforts, and existing federal authorities. Our context is the U.S. public health goal to eliminate pediatric elevated blood lead levels (EBLs) by 2010. National, state, and local exposure assessments over the past half century have identified risk factors for EBLs among U.S. children, including age, race, income, age and location of housing, parental occupation, and season. Recent national policies have greatly reduced lead exposure among U.S. children, but even very low exposure levels compromise children's later intellectual development and lifetime achievement. No threshold for these effects has been demonstrated. Although lead paint and dust may still account for up to 70% of EBLs in U.S. children, the U.S. Centers for Disease Control and Prevention estimates that >or=30% of current EBLs do not have an immediate lead paint source, and numerous studies indicate that lead exposures result from multiple sources. EBLs and even deaths have been associated with inadequately controlled sources including ethnic remedies and goods, consumer products, and food-related items such as ceramics. Lead in public drinking water and in older urban centers remain exposure sources in many areas. Achieving the 2010 goal requires maintaining current efforts, especially programs addressing lead paint, while developing interventions that prevent exposure before children are poisoned. It also requires active collaboration across all levels of government to identify and control all potential sources of lead exposure, as well as primary prevention.

Lead remediation and changes in human lead exposure: some physiological and biokinetic dimensions.

PubMed

Mushak, Paul

2003-02-15

This paper presents a qualitative and quantitative analysis of the various aspects of lead remediation effectiveness with particular reference to human health risk assessment. One of the key elements of lead remediation efforts at such sites as those under the Superfund program deals with populations at elevated exposure and toxicity risk in the proximity of, or at, the site of remediation, especially remediation workers, workers at other tasks on sites that were remediated down to some action level of lead concentration in soils, and groups at risk in nearby communities. A second element has to do with how one measures or models lead exposure changes with special reference to baseline and post-remediation conditions. Various biomarkers of lead exposure can be employed, but their use requires detailed knowledge of what results using each means. The most commonly used approach is measurement of blood lead (Pb-B). Recognized limitations in the use of Pb-B has led to the use of predictive Pb exposure models, which are less vulnerable to the many behavioral, physiological, and environmental parameters that can distort isolated or 'single shot' Pb-B testings. A third aspect covered in this paper presents various physiological factors that affect the methods by which one evaluates Pb remediation effectiveness. Finally, this article offers an integrated look at how lead remediation actions directed at one lead source or pathway affect the total lead exposure picture for human populations at elevated lead exposure and toxicity risk.

Lead exposure in radiator repair workers: a survey of Washington State radiator repair shops and review of occupational lead exposure registry data.

PubMed

Whittaker, Stephen G

2003-07-01

Radiator repair workers in Washington State have the greatest number of very elevated (> or =60 microg/dL) blood lead levels of any other worker population. The goals of this study were to determine the number of radiator repair workers potentially exposed to lead; estimate the extent of blood lead data underreporting to the Occupational Lead Exposure Registry; describe current safety and health practices in radiator repair shops; and determine appropriate intervention strategies to reduce exposure and increase employer and worker awareness. Lead exposure in Washington State's radiator repair workers was assessed by reviewing Registry data and conducting a statewide survey of radiator repair businesses. This study revealed that a total of 226 workers in Washington State (including owner-operators and all employees) conduct repair activities that could potentially result in excessive exposures to lead. Approximately 26% of radiator repair workers with elevated blood lead levels (> or =25 microg/dL) were determined to report to Washington State's Registry. This study also revealed a lack of awareness of lead's health effects, appropriate industrial hygiene controls, and the requirements of the Lead Standard. Survey respondents requested information on a variety of workplace health and safety issues and waste management; 80% requested a confidential, free-of-charge consultation. Combining data derived from an occupational health surveillance system and a statewide mail survey proved effective at characterizing lead exposures and directing public health intervention in Washington State.

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

PubMed

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

1997-03-01

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

Lepidium meyenii (Maca) reversed the lead acetate induced -- damage on reproductive function in male rats.

PubMed

Rubio, Julio; Riqueros, Marissa I; Gasco, Manuel; Yucra, Sandra; Miranda, Sara; Gonzales, Gustavo F

2006-07-01

Rats were treated with 0, 8, 16 and 24 mg/kg of lead acetate (LA) (i.p.) for 35 days with or without Maca. Maca was co-administrated orally from day 18 to day 35. The lengths of stages of the seminiferous epithelium were assessed by transillumination. Also, sex organ weights, testicular and epididymal sperm count, sperm motility, daily sperm production, sperm transit rate and serum testosterone levels were measured. Lead acetate treatment resulted in a dose-response reduction of lengths of stages VIII and IX-XI, and serum testosterone levels. However, rats treated with 8 and 16 mg/kg but not 24 mg/kg of lead acetate showed a low number of testicular spermatids, low daily sperm production (DSP) and low epididymal sperm count. Administration of Maca to rats treated with lead acetate resulted in higher lengths of stages VIII and IX-XI with respect to lead acetate-treated rats. Moreover, treatment with Maca to lead acetate-treated rats resulted in lengths of stages VIII and IX-XI similar to the control group. Maca administration also reduced the deleterious effect on DSP caused by lead acetate treatment. Maca prevented LA-induced spermatogenic disruption in rats and it may become in a potential treatment of male infertility associated with lead exposure.

The effect of D-cycloserine on subliminal cue exposure in spider fearful individuals.

PubMed

Gutner, Cassidy A; Weinberger, Joel; Hofmann, Stefan G

2012-01-01

Research on D-cycloserine (DCS) has demonstrated a significant effect on symptom reduction in human studies that utilized conventional exposure-based approaches. Recent studies have offered promising results for targeting fears through subliminal paradigms. In this double-blind, randomized placebo-controlled study, 45 spider fearful individuals received DCS or placebo pills prior to completing a subliminal cue exposure task to images of spiders. Participants completed self-report questionnaires and a behavioral approach task to a live caged tarantula. After repeated exposure to subliminal spider cues, participants in the DCS group reported a greater reduction in disgust than individuals in the placebo group. No difference was observed in fear ratings. These findings suggest that DCS augments the reduction in disgust in spider fearful subjects after subliminal exposure to spider cues.

A meta-analysis of observational studies of the association between chronic occupational exposure to lead and amyotrophic lateral sclerosis.

PubMed

Wang, Ming-Dong; Gomes, James; Cashman, Neil R; Little, Julian; Krewski, Daniel

2014-12-01

The association between occupational exposure to lead and amyotrophic lateral sclerosis (ALS) was examined through systematic review and meta-analyses of relevant epidemiological studies and reported according to PRISMA guidelines. Relevant studies were searched in multiple bibliographic databases through September 2013; additional articles were tracked through PubMed until submission. All records were screened in DistillerSR, and the data extracted from included articles were synthesized with meta-analysis. The risk of developing ALS among individuals with a history of exposure to lead was almost doubled (odds ratio, 1.81; 95% confidence interval, 1.39 to 2.36) on the basis of nine included case-control studies with specific lead exposure information, with no apparent heterogeneity across included studies (I = 14%). The attributable risk of ALS because of exposure to lead was estimated to be 5%. Previous exposure to lead may be a risk factor for ALS.

Exposure to Low Levels of Lead in Utero and Umbilical Cord Blood DNA Methylation in Project Viva: An Epigenome-Wide Association Study

PubMed Central

Hivert, Marie-France; Cardenas, Andres; Zhong, Jia; Rifas-Shiman, Sheryl L.; Agha, Golareh; Colicino, Elena; Just, Allan C.; Amarasiriwardena, Chitra; Lin, Xihong; Litonjua, Augusto A.; DeMeo, Dawn L.; Gillman, Matthew W.; Wright, Robert O.; Oken, Emily

2017-01-01

Background: Early-life exposure to lead is associated with deficits in neurodevelopment and with hematopoietic system toxicity. DNA methylation may be one of the underlying mechanisms for the adverse effects of prenatal lead on the offspring, but epigenome-wide methylation data for low levels of prenatal lead exposure are lacking. Objectives: We investigated the association between prenatal maternal lead exposure and epigenome-wide DNA methylation in umbilical cord blood nucleated cells in Project Viva, a prospective U.S.-based prebirth cohort with relatively low levels of lead exposure. Methods: Among 268 mother–infant pairs, we measured lead concentrations in red blood cells (RBC) from prenatal maternal blood samples, and using HumanMethylation450 Bead Chips, we measured genome-wide methylation levels at 482,397 CpG loci in umbilical cord blood and retained 394,460 loci after quality control. After adjustment for batch effects, cell types, and covariates, we used robust linear regression models to examine associations of prenatal lead exposure with DNA methylation in cord blood at epigenome-wide significance level [false discovery rate (FDR)<0.05]. Results: The mean [standard deviation (SD)] maternal RBC lead level was 1.22 (0.63) μg/dL. CpG cg10773601 showed an epigenome-wide significant negative association with prenatal lead exposure (−1.4% per doubling increase in lead exposure; p=2.3×10−7) and was annotated to C-Type Lectin Domain Family 11, Member A (CLEC11A), which functions as a growth factor for primitive hematopoietic progenitor cells. In sex-specific analyses, we identified more CpGs with FDR<0.05 among female infants (n=38) than among male infants (n=2). One CpG (cg24637308), which showed a strong negative association with prenatal lead exposure among female infants (−4.3% per doubling increase in lead exposure; p=1.1×10−06), was annotated to Dynein Heavy Chain Domain 1 gene (DNHD1) which is highly expressed in human brain. Interestingly, there were strong correlations between blood and brain methylation for CpG (cg24637308) based on another independent set of samples with a high proportion of female participants. Conclusion: Prenatal low-level lead exposure was associated with newborn DNA methylation, particularly in female infants. https://doi.org/10.1289/EHP1246 PMID:28858830

Exposure to Low Levels of Lead in Utero and Umbilical Cord Blood DNA Methylation in Project Viva: An Epigenome-Wide Association Study.

PubMed

Wu, Shaowei; Hivert, Marie-France; Cardenas, Andres; Zhong, Jia; Rifas-Shiman, Sheryl L; Agha, Golareh; Colicino, Elena; Just, Allan C; Amarasiriwardena, Chitra; Lin, Xihong; Litonjua, Augusto A; DeMeo, Dawn L; Gillman, Matthew W; Wright, Robert O; Oken, Emily; Baccarelli, Andrea A

2017-08-25

Early-life exposure to lead is associated with deficits in neurodevelopment and with hematopoietic system toxicity. DNA methylation may be one of the underlying mechanisms for the adverse effects of prenatal lead on the offspring, but epigenome-wide methylation data for low levels of prenatal lead exposure are lacking. We investigated the association between prenatal maternal lead exposure and epigenome-wide DNA methylation in umbilical cord blood nucleated cells in Project Viva, a prospective U.S.-based prebirth cohort with relatively low levels of lead exposure. Among 268 mother-infant pairs, we measured lead concentrations in red blood cells (RBC) from prenatal maternal blood samples, and using HumanMethylation450 Bead Chips, we measured genome-wide methylation levels at 482,397 CpG loci in umbilical cord blood and retained 394,460 loci after quality control. After adjustment for batch effects, cell types, and covariates, we used robust linear regression models to examine associations of prenatal lead exposure with DNA methylation in cord blood at epigenome-wide significance level [false discovery rate (FDR)<0.05]. The mean [standard deviation (SD)] maternal RBC lead level was 1.22 (0.63) μg/dL. CpG cg10773601 showed an epigenome-wide significant negative association with prenatal lead exposure (-1.4% per doubling increase in lead exposure; p=2.3×10-7) and was annotated to C-Type Lectin Domain Family 11, Member A ( CLEC11A ), which functions as a growth factor for primitive hematopoietic progenitor cells. In sex-specific analyses, we identified more CpGs with FDR<0.05 among female infants (n=38) than among male infants (n=2). One CpG (cg24637308), which showed a strong negative association with prenatal lead exposure among female infants (-4.3% per doubling increase in lead exposure; p=1.1×10-06), was annotated to Dynein Heavy Chain Domain 1 gene ( DNHD1 ) which is highly expressed in human brain. Interestingly, there were strong correlations between blood and brain methylation for CpG (cg24637308) based on another independent set of samples with a high proportion of female participants. Prenatal low-level lead exposure was associated with newborn DNA methylation, particularly in female infants. https://doi.org/10.1289/EHP1246.

Climate Change and Our Environment: The Effect on Respiratory and Allergic Disease

PubMed Central

Barnes, Charles S.; Alexis, Neil E.; Bernstein, Jonathan A.; Cohn, John R.; Demain, Jeffrey G.; Horner, Elliott; Levetin, Estelle; Nel, Andre; Phipatanakul, Wanda

2013-01-01

Climate change is a constant and ongoing process. It is postulated that human activities have reached a point at which we are producing global climate change. This article provides suggestions to help the allergist/environmental physician integrate recommendations about improvements in outdoor and indoor air quality and the likely response to predicted alterations in the earth’s environment into their patient’s treatment plan. Many changes that affect respiratory disease are anticipated. Examples of responses to climate change include energy reduction retrofits in homes that could potentially affect exposure to allergens and irritants, more hot sunny days that increase ozone-related difficulties, and rises in sea level or altered rainfall patterns that increase exposure to damp indoor environments. Climate changes can also affect ecosystems, manifested as the appearance of stinging and biting arthropods in new areas. Higher ambient carbon dioxide concentrations, warmer temperatures, and changes in floristic zones could potentially increase exposure to ragweed and other outdoor allergens, whereas green practices such as composting can increase allergen and irritant exposure. Finally, increased energy costs may result in urban crowding and human source pollution, leading to changes in patterns of infectious respiratory illnesses. Improved governmental controls on airborne pollutants could lead to cleaner air and reduced respiratory diseases but will meet strong opposition because of their effect on business productivity. The allergy community must therefore adapt, as physician and research scientists always have, by anticipating the needs of patients and by adopting practices and research methods to meet changing environmental conditions. PMID:23687635

Animal Models of Human Disease: Severe and Mild Lead Encephalopathy in the Neonatal Rat*

PubMed Central

Michaelson, I. Arthur; Sauerhoff, Mitchell W.

1974-01-01

Inorganic lead produces cerebral dysfunction and clinically definable encephalopathies in man. To date there have been few studies on the biochemical changes in brain following exposure to inorganic lead. Studies correlating toxicity with behavioral and brain neurochemical changes following lead exposure have been hindered because adult laboratory animals are resistant to the central nervous system effects of lead poisoning. Such studies have been impeded by lack of suitable experimental models until Pentschew and Garro showed that brain lesions develop in neonatal rats when a pregnant rat newly delivered of her litter is placed on a 4% lead carbonate containing diet. Lead passes into the developing sucklings via maternal milk. Lead-poisoned new-borns have pronounced retardation of growth and during the fourth week of ilfe develop the severe signs of lead encephalopathy, namely, extensive histological lesions of the cerebellum, brain edema, and paraplegia. There is an approximate 85-fold increase in the lead concentration of both the cerebellum and cerebral cortex relative to controls, but edema and gross vascular changes are confined to the cerebellum. Ingested lead had little effect on RNA, DNA, and protein concentrations of developing rat cerebellum and cerebral cortex. However, there was a reduction of between 10 and 20% in the DNA content of the cerebellum around 3 weeks of age in the lead-exposed sucklings. This suggests a failure of cell multiplication in this part of the brain. A critical evaluation of this experimental approach indicated that under similar dietary conditions experimental lactating rats eat 30% less food than controls resulting in: (a) sustained loss in body weight of nursing mothers and that (b) offsprings who develop paraplegia and cerebellar damage do so after gaining access to lead containing diet. We have studied mothers' food consumption and body weight changes and blood, milk, and brain lead content; and newborns' body and brain weight changes, blood and brain lead content, and brain serotonin (5HT), norepinephrine (NE), dopamine (DA), and γ-aminobutyric acid (GABA). We have found that a lactating mother rat eating 5% lead acetate (2.73% Pb) produced milk containing 25 ppm lead. When the mothers' diet is changed at day 16 from 5% PbAc to one containing 25 ppm Pb, and neonates allowed free access to the solid diet, the sucklings still have retarded body growth but do not develop paraplegia or grossly apparent vascular damage of the cerebellum. However, during the fourth week these animals exhibit a less severe form of “encephalopathy” consisting of hyperactivity, tremors, and stereotype behavior. Pair-fed controls coetaneous to experimental groups do not display such activities. There was no change in brain 5HT, GABA, or NE, but a 15–20% decrease in brain DA. Change in DA relative to other monoamines suggests a relationship between CNS dysfunction due to lead and DA metabolism in the brain. The experimental design as discribed provides a model of CNS dysfunction due to lead exposure without debilitating histopathologies. It is possible that our findings on increased motor activity and changes in brain dopamine may correspond to early responses to lead exposure before recognized overt signs of toxicity. ImagesFIGURE 1.FIGURE 2. PMID:4831141

EVIDENCE FOR EFFECTS OF CHRONIC LEAD EXPOSURE ON BLOOD PRESSURE IN EXPERIMENTAL ANIMALS: AN OVERVIEW

EPA Science Inventory

Information obtained in a number of experimental studies conducted over the last forty years on the effects of lead on blood pressure is reviewed. Differences in animal species, age at beginning of exposure, level of lead exposure, indices of lead burden, and blood pressure effec...

Competitive short-term and long-term memory processes in spatial habituation.

PubMed

Sanderson, David J; Bannerman, David M

2011-04-01

Exposure to a spatial location leads to habituation of exploration such that, in a novelty preference test, rodents subsequently prefer exploring a novel location to the familiar location. According to Wagner's (1981) theory of memory, short-term and long-term habituation are caused by separate and sometimes opponent processes. In the present study, this dual-process account of memory was tested. Mice received a series of exposure training trials to a location before receiving a novelty preference test. The novelty preference was greater when tested after a short, rather than a long, interval. In contrast, the novelty preference was weaker when exposure training trials were separated by a short, rather than a long interval. Furthermore, it was found that long-term habituation was determined by the independent effects of the amount of exposure training and the number of exposure training trials when factors such as the intertrial interval and the cumulative intertrial interval were controlled. A final experiment demonstrated that a long-term reduction of exploration could be caused by a negative priming effect due to associations formed during exploration. These results provide evidence against a single-process account of habituation and suggest that spatial habituation is determined by both short-term, recency-based memory and long-term, incrementally strengthened memory.

Exposure to Community Violence and the Trajectory of Internalizing and Externalizing Symptoms in a Sample of Low-Income Urban Youth.

PubMed

Taylor, Jeremy J; Grant, Kathryn E; Zulauf, Courtney A; Fowler, Patrick J; Meyerson, David A; Irsheid, Sireen

2018-01-01

This study examined trajectories of psychopathology in a sample of low-income urban youth and tested exposure to community violence as a predictor of these trajectories. Self-report and parent-report survey measures of psychological problems and exposure to community violence were collected annually over 3 years from a sample of 364 fifth- to ninth-grade low-income urban youth (64% female; 95% youth of color). Linear growth models showed that youth experienced declines in both internalizing and externalizing symptoms across adolescence. Exposure to community violence was more strongly associated with externalizing symptoms than with internalizing symptoms but predicted declines in both types of symptoms. Results also indicated that youth reported more internalizing and externalizing symptoms than their parents reported for them. Exposure to community violence may explain unique trajectories of mental health problems among low-income urban youth. In addition, youth efforts to adopt a tough façade in the face of community violence could lead to higher rates of externalizing problems relative to internalizing problems, whereas desensitization processes may better explain reductions in both types of symptoms over time. Finally, youth report may be more valid than parent report in the context of urban poverty.

Motor neuron disease mortality and lifetime petrol lead exposure: Evidence from national age-specific and state-level age-standardized death rates in Australia.

PubMed

Zahran, Sammy; Laidlaw, Mark A S; Rowe, Dominic B; Ball, Andrew S; Mielke, Howard W

2017-02-01

The age standardized death rate from motor neuron disease (MND) for persons 40-84 years of age in the Australian States of New South Wales, Victoria, and Queensland increased dramatically from 1958 to 2013. Nationally, age-specific MND death rates also increased over this time period, but the rate of the rise varied considerably by age-group. The historic use of lead (Pb) additives in Australian petrol is a candidate explanation for these trends in MND mortality (International Classification of Disease (ICD)-10 G12.2). Leveraging temporal and spatial variation in petrol lead exposure risk resulting from the slow rise and rapid phase-out of lead as a constituent in gasoline in Australia, we analyze relationships between (1) national age-specific MND death rates in Australia and age-specific lifetime petrol lead exposure, (2) annual between-age dispersions in age-specific MND death rates and age-specific lifetime petrol lead exposure; and (3) state-level age-standardized MND death rates as a function of age-weighted lifetime petrol lead exposure. Other things held equal, we find that a one percent increase in lifetime petrol lead exposure increases the MND death rate by about one-third of one percent in both national age-specific and state-level age-standardized models of MND mortality. Lending support to the supposition that lead exposure is a driver of MND mortality risk, we find that the annual between-age group standard deviation in age-specific MND death rates is strongly correlated with the between-age standard deviation in age-specific lifetime petrol lead exposure. Legacy petrol lead emissions are associated with age-specific MND death rates as well as state-level age-standardized MND death rates in Australia. Results indicate that we are approaching peak lead exposure-attributable MND mortality. Copyright © 2016 Elsevier Inc. All rights reserved.

National demonstration of full reactor coolant system (RCS) chemical decontamination at Indian Point 2

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

Trovato, S.A.; Parry, J.O.

1995-03-01

Key to the safe and efficient operation of the nation`s civilian nuclear power plants is the performance of maintenance activities within regulations and guidelines for personnel radiation exposure. However, maintenance activities, often performed in areas of relatively high radiation fields, will increase as the nation`s plant age. With the Nuclear Regulatory Commission (NRC) lowering the allowable radiation exposure to plant workers in 1994 and considering further reductions and regulations in the future, it is imperative that new techniques be developed and applied to reduce personnel exposure. Full primary system chemical decontamination technology offers the potential to be single most effectivemore » method of maintaining workers exposure {open_quotes}as low as reasonably achievable{close_quotes} (ALARA) while greatly reducing plant operation and maintenance (O&M) costs. A three-phase program underway since 1987, has as its goal to demonstrate that full RCS decontamination is a visible technology to reduce general plant radiation levels without threatening the long term reliability and operability of a plant. This paper discusses research leading to and plans for a National Demonstration of Full RCS Chemical Decontamination at Indian Point 2 nuclear generating station in 1995.« less

Human Physiological Responses to Acute and Chronic Cold Exposure

NASA Technical Reports Server (NTRS)

Stocks, Jodie M.; Taylor, Nigel A. S.; Tipton, Michael J.; Greenleaf, John E.

2001-01-01

When inadequately protected humans are exposed to acute cold, excessive body heat is lost to the environment and unless heat production is increased and heat loss attenuated, body temperature will decrease. The primary physiological responses to counter the reduction in body temperature include marked cutaneous vasoconstriction and increased metabolism. These responses, and the hazards associated with such exposure, are mediated by a number of factors which contribute to heat production and loss. These include the severity and duration of the cold stimulus; exercise intensity; the magnitude of the metabolic response; and individual characteristics such as body composition, age, and gender. Chronic exposure to a cold environment, both natural and artificial, results in physiological alterations leading to adaptation. Three quite different, but not necessarily exclusive, patterns of human cold adaptation have been reported: metabolic, hypothermic, and insulative. Cold adaptation has also been associated with an habituation response, in which there is a desensitization, or damping, of the normal response to a cold stress. This review provides a comprehensive analysis of the human physiological and pathological responses to cold exposure. Particular attention is directed to the factors contributing to heat production and heat loss during acute cold stress, and the ability of humans to adapt to cold environments.

Studies on battery repair and recycling workers occupationally exposed to lead in Karachi.

PubMed

Haider, Muhammad Jamal; Qureshi, Naeemullah

2013-01-01

OBJECTIVE. The present study was carried out to investigate the effects of occupational lead exposure on the hematological and biochemical parameters in occupationally exposed and non exposed inhabitants of Karachi. MATERIAL AND METHODS. In 100 lead exposed subjects recruited from automobile workshops, lead battery repair and recycling units located in Karachi and in 100 control subjects the general health status, hematological parameters and exposure markers for lead were measured. RESULTS. Results indicated that the mean values of blood lead level and delta-aminolevulinic acid were significantly higher (P<0.05) while the activity of delta-aminolevulinic acid dehydratase were significantly decreased (P<0.05) among battery repair and recycling workers as compared to controls. The abnormalities in the blood lead level, delta-aminolevulinic acid and delta-aminolevulinic acid dehydratase were more frequent in lead exposed battery repair workers when compared with control subjects. The blood lead levels and deltaaminolevulinic acid were positively correlated while delta-aminolevulinic acid dehydratase was found to be negatively correlated with age, years of exposure and years of employment. Blood lead level was positively correlated with hemoglobin and RBC count while delta-aminolevulinic acid dehydratase was negatively correlated with hemoglobin concentration. The work related symptoms, droopiness, nasal symptoms and muscular pain were more frequent among battery repair workers as compared to control group. The findings of present study confirmed that occupational exposure to lead is associated with deviation in important hematological parameters and biological markers of exposure to lead among lead exposed workers, and also confirms the impact of lead exposure in the development of adverse effects among lead exposed workers. The study provides the data for risk assessment in lead battery repair workers of Karachi and suggests the need for preventive measures for battery repair workers and improvements to reduce occupational lead exposures to protect them from lead toxicity. It is suggested that hematological and physical examinations of lead exposed workers should be carried out periodically to prevent future health hazards.

Lead exposure and rate of change in cognitive function in older women

PubMed Central

Power, Melinda C; Korrick, Susan; Tchetgen Tchetgen, Eric J; Nie, Linda H; Grodstein, Francine; Hu, Howard; Weuve, Jennifer; Schwartz, Joel; Weisskopf, Marc G

2014-01-01

Background Higher long-term cumulative lead exposure predicts faster cognitive decline in older men, but evidence of an association in women is lacking. Objective To determine if there is an association between lead exposure and cognitive decline in women. Methods This study considers a sample of 584 women from the Nurses’ Health Study who live in or near Boston, Massachusetts. We quantified lead exposure using biomarkers of lead exposure assessed in 1993–2004 and evaluated cognitive decline by repeated performance on a telephone battery of cognitive tests primarily assessing learning, memory, executive function, and attention completed in 1995–2008. All cognitive test scores were z-transformed for use in analyses. We used linear mixed models with random effects to quantify the association between each lead biomarker and change in cognition overall and on each individual test. Results Consideration of individual tests showed greater cognitive decline with increased tibia lead concentrations, a measure of long-term cumulative exposure, for story memory and category fluency. The estimated excess annual decline in overall cognitive test z-score per SD increase in tibia bone lead concentration was suggestive, although the confidence intervals included the null (0.024 standard units, 95% confidence interval: −0.053 , 0.004 – an additional decline in function equivalent to being 0.33 years older). We found little support for associations between cognitive decline and patella or blood lead, which provide integrated measures of exposure over shorter timeframes. Conclusions Long-term cumulative lead exposure may be weakly associated with faster cognitive decline in community-dwelling women, at least in some cognitive domains. PMID:24529005

Recycling Perovskite Solar Cells To Avoid Lead Waste.

PubMed

Binek, Andreas; Petrus, Michiel L; Huber, Niklas; Bristow, Helen; Hu, Yinghong; Bein, Thomas; Docampo, Pablo

2016-05-25

Methylammonium lead iodide (MAPbI3) perovskite based solar cells have recently emerged as a serious competitor for large scale and low-cost photovoltaic technologies. However, since these solar cells contain toxic lead, a sustainable procedure for handling the cells after their operational lifetime is required to prevent exposure of the environment to lead and to comply with international electronic waste disposal regulations. Herein, we report a procedure to remove every layer of the solar cells separately, which gives the possibility to selectively isolate the different materials. Besides isolating the toxic lead iodide in high yield, we show that the PbI2 can be reused for the preparation of new solar cells with comparable performance and in this way avoid lead waste. Furthermore, we show that the most expensive part of the solar cell, the conductive glass (FTO), can be reused several times without any reduction in the performance of the devices. With our simple recycling procedure, we address both the risk of contamination and the waste disposal of perovskite based solar cells while further reducing the cost of the system. This brings perovskite solar cells one step closer to their introduction into commercial systems.

Modeling the population-level effects of hypoxia on a coastal fish: implications of a spatially-explicit individual-based model

NASA Astrophysics Data System (ADS)

Rose, K.; Creekmore, S.; Thomas, P.; Craig, K.; Neilan, R.; Rahman, S.; Wang, L.; Justic, D.

2016-02-01

The northwestern Gulf of Mexico (USA) currently experiences a large hypoxic area ("dead zone") during the summer. The population-level effects of hypoxia on coastal fish are largely unknown. We developed a spatially-explicit, individual-based model to analyze how hypoxia effects on reproduction, growth, and mortality of individual Atlantic croaker could lead to population-level responses. The model follows the hourly growth, mortality, reproduction, and movement of individuals on a 300 x 800 spatial grid of 1 km2 cells for 140 years. Chlorophyll-a concentration and water temperature were specified daily for each grid cell. Dissolved oxygen (DO) was obtained from a 3-D water quality model for four years that differed in their severity of hypoxia. A bioenergetics model was used to represent growth, mortality was assumed stage- and age-dependent, and movement behavior was based on temperature preferences and avoidance of low DO. Hypoxia effects were imposed using exposure-effects sub-models that converted time-varying exposure to DO to reductions in growth and fecundity, and increases in mortality. Using sequences of mild, intermediate, and severe hypoxia years, the model predicted a 20% decrease in population abundance. Additional simulations were performed under the assumption that river-based nutrients loadings that lead to more hypoxia also lead to higher primary production and more food for croaker. Twenty-five percent and 50% nutrient reduction scenarios were simulated by adjusting the cholorphyll-a concentrations used as food proxy for the croaker. We then incrementally increased the DO concentrations to determine how much hypoxia would need to be reduced to offset the lower food production resulting from reduced nutrients. We discuss the generality of our results, the hidden effects of hypoxia on fish, and our overall strategy of combining laboratory and field studies with modeling to produce robust predictions of population responses to stressors under dynamic and multi-stressor conditions.

Psychiatric epidemiologic study of occupational lead exposure

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

Parkinson, D.K.; Ryan, C.; Bromet, E.J.

1986-02-01

The association of occupational lead exposure with neuropsychiatric functioning was evaluated using data collected in 1982 in eastern Pennsylvania from 288 lead-exposed workers and 181 nonexposed subjects. Both current and cumulative exposure indices were used. After controlling for age, education, and income, few meaningful differences between exposed and control workers were found on either neuropsychologic or psychosocial variables. Dose-response analyses indicated that among lead-exposed workers, cumulative and current exposure were unrelated to neuropsychologic performance. The only meaningful associations occurred between exposure and level of conflict in interpersonal relationships. The results thus give evidence against hypotheses suggesting adverse neuropsychologic effects.

A Comparison between Temperature-Controlled Laminar Airflow Device and a Room Air-Cleaner in Reducing Exposure to Particles While Asleep

PubMed Central

Spilak, Michal P.; Sigsgaard, Torben; Takai, Hisamitsu; Zhang, Guoqiang

2016-01-01

People spend approximately one third of their life sleeping. Exposure to pollutants in the sleep environment often leads to a variety of adverse health effects, such as development and exacerbation of asthma. Avoiding exposure to these pollutants by providing a sufficient air quality in the sleep environment might be a feasible method to alleviate these health symptoms. We performed full-scale laboratory measurements using a thermal manikin positioned on an experimental bed. Three ventilation settings were tested: with no filtration system operated, use of portable air cleaner and use of a temperature-controlled laminar airflow (TLA) device. The first part of the experiment investigated the air-flow characteristics in the breathing zone. In the second part, particle removal efficiency was estimated. Measured in the breathing zone, the room air cleaner demonstrated high turbulence intensity, high velocity and turbulence diffusivity level, with a particle reduction rate of 52% compared to baseline after 30 minutes. The TLA device delivered a laminar airflow to the breathing zone with a reduction rate of 99.5%. During a periodical duvet lifting mimicking a subject’s movement in bed, the particle concentration was significantly lower with the TLA device compared to the room air cleaner. The TLA device provided a barrier which significantly reduced the introduction of airborne particles into the breathing zone. Further studies should be conducted for the understanding of the transport of resuspended particles between the duvet and the laying body. PMID:27898693

A Comparison between Temperature-Controlled Laminar Airflow Device and a Room Air-Cleaner in Reducing Exposure to Particles While Asleep.

PubMed

Spilak, Michal P; Sigsgaard, Torben; Takai, Hisamitsu; Zhang, Guoqiang

2016-01-01

People spend approximately one third of their life sleeping. Exposure to pollutants in the sleep environment often leads to a variety of adverse health effects, such as development and exacerbation of asthma. Avoiding exposure to these pollutants by providing a sufficient air quality in the sleep environment might be a feasible method to alleviate these health symptoms. We performed full-scale laboratory measurements using a thermal manikin positioned on an experimental bed. Three ventilation settings were tested: with no filtration system operated, use of portable air cleaner and use of a temperature-controlled laminar airflow (TLA) device. The first part of the experiment investigated the air-flow characteristics in the breathing zone. In the second part, particle removal efficiency was estimated. Measured in the breathing zone, the room air cleaner demonstrated high turbulence intensity, high velocity and turbulence diffusivity level, with a particle reduction rate of 52% compared to baseline after 30 minutes. The TLA device delivered a laminar airflow to the breathing zone with a reduction rate of 99.5%. During a periodical duvet lifting mimicking a subject's movement in bed, the particle concentration was significantly lower with the TLA device compared to the room air cleaner. The TLA device provided a barrier which significantly reduced the introduction of airborne particles into the breathing zone. Further studies should be conducted for the understanding of the transport of resuspended particles between the duvet and the laying body.

Octyl gallate reduces ATP levels and Ki67 expression leading HepG2 cells to cell cycle arrest and mitochondria-mediated apoptosis.

PubMed

Lima, Kelly Goulart; Krause, Gabriele Catyana; da Silva, Elisa Feller Gonçalves; Xavier, Léder Leal; Martins, Léo Anderson Meira; Alice, Laura Manzoli; da Luz, Luiza Bueno; Gassen, Rodrigo Benedetti; Filippi-Chiela, Eduardo Cremonese; Haute, Gabriela Viegas; Garcia, Maria Claudia Rosa; Funchal, Giselle Afonso; Pedrazza, Leonardo; Reghelin, Camille Kirinus; de Oliveira, Jarbas Rodrigues

2018-04-01

Octyl gallate (OG) is an antioxidant that has shown anti-tumor, anti-diabetic and anti-amyloidogenic activities. Mitochondria play an important role in hepatocellular carcinoma, mainly by maintaining accelerated cellular proliferation through the production of ATP. Thus, the mitochondria may be a target for antitumor therapies. Here, we investigated the effects of OG in the hepatocarcinoma cell line (HepG2) and the mechanisms involved. We report, for the first time, that treatment with OG for 24h inhibited HepG2 cell growth by decreasing mitochondrial activity and mass, which led to the reduction of ATP levels. This reduction in the energy supply triggered a decrease in Ki67 protein expression, leading cells to cycle arrest. In addition, treatment with two doses of OG for 48h induced loss of mitochondrial functionality, mitochondrial swelling and apoptosis. Finally, we report that HepG2 cells had no resistance to treatment after multiple doses. Collectively, our findings indicate that metabolic dysregulation and Ki67 protein reduction are key events in the initial anti-proliferative action of OG, whereas mitochondrial swelling and apoptosis induction are involved in the action mechanism of OG after prolonged exposure. This suggests that OG targets mitochondria, thus representing a candidate for further research on therapies for hepatocarcinoma. Copyright © 2017 Elsevier Ltd. All rights reserved.

Cognitive disparities, lead plumbing, and water chemistry: prior exposure to water-borne lead and intelligence test scores among World War Two U.S. Army enlistees.

PubMed

Ferrie, Joseph P; Rolf, Karen; Troesken, Werner

2012-01-01

Higher prior exposure to water-borne lead among male World War Two U.S. Army enlistees was associated with lower intelligence test scores. Exposure was proxied by urban residence and the water pH levels of the cities where enlistees lived in 1930. Army General Classification Test scores were six points lower (nearly 1/3 standard deviation) where pH was 6 (so the water lead concentration for a given amount of lead piping was higher) than where pH was 7 (so the concentration was lower). This difference rose with time exposed. At this time, the dangers of exposure to lead in water were not widely known and lead was ubiquitous in water systems, so these results are not likely the effect of individuals selecting into locations with different levels of exposure. Copyright © 2011 Elsevier B.V. All rights reserved.

[Blood cerebrospinal fluid barrier damage of rats induced by lead acetate or nano-lead exposure].

PubMed

Feng, P P; Zhai, F J; Jiang, S F; Wu, J Z; Xue, L; Zheng, M M; Zhou, L L; Meng, C Y; Cao, M Y; Zhang, Y S

2016-05-20

To investigate the damage of blood-cerebrospinal fluid barrier (BCB) of rats induced by lead and nano-lead exposure in order to provide the basis for mechanism study of lead neurotoxicity. 39 male rats were randomly divided into control group, lead acetate exposed group and nano-lead exposed group. Rats in lead acetate exposed group and nano-lead exposed group were given 20 mg/kg lead acetate or nano-lead by oral gavage and rats in control groups were given the same amount saline for 9 weeks.Morris maze was used to test the learning function, serum albumin and CSF albumin were determined by ELISA. Confocal laser scanning microscope was applied to detect ZO-1 and Occludin protein expression in choroid plexus, real time-PCR was used to test the expression of ZO-1 and Occludin mRNA expression. Pathological changes of choroid plexus cells were observed by the electron microscopy. Compared with the control group, the escape latency of rats in lead acetate or nano-lead exposure group were longer and times of across platform were less. The levels of CSF albumin and the CSF albumin index in lead acetate or nano-lead exposed rats were obviously higher, and the fluorescence intensity of ZO-1, Occludin as well as mRNA expressions were lower than those in control group(P<0.05). Compared with lead acetate exposed group, the levels of CSF albumin and the CSF albumin index in nano-lead exposure group were higher. The fluorescence intensity and mRNA expressions of ZO-1, Occludin in nano-lead exposure group were than those in lead acetate group(P<0.05). Electron microscopy revealed that lead acetate or nano-lead exposure could induce shorter microvillus of choroid plexus epithelial cells, mitochondrion destruction and partial disconnection in intracellular junctions between two adjacent epithelial cells. Lead acetate and nano-lead exposed can result in the blood-cerebrospinal fluid barrier damage, which may involve in the process of lead induced neurotoxicity. Meanwhile, nano-lead exposure can induced in more worse damage in terms of blood-results in blood-cerebrospinal fluid barrier function.

Effects of lead on Na+, K+-ATPase and hemolymph ion concentrations in the freshwater mussel Elliptio complanata

USGS Publications Warehouse

Mosher, Shad; Cope, W. Gregory; Weber, Frank X.; Shea, Damian; Kwak, Thomas J.

2012-01-01

Freshwater mussels are an imperiled fauna exposed to a variety of environmental toxicants such as lead (Pb) and studies are urgently needed to assess their health and condition to guide conservation efforts. A 28-day laboratory toxicity test with Pb and adult Eastern elliptio mussels (Elliptio complanata) was conducted to determine uptake kinetics and to assess the toxicological effects of Pb exposure. Test mussels were collected from a relatively uncontaminated reference site and exposed to a water-only control and five concentrations of Pb (as lead nitrate) ranging from 1 to 245 mu g/L in a static renewal test with a water hardness of 42 mg/L. Endpoints included tissue Pb concentrations, hemolymph Pb and ion (Na+, K+, Cl-, Ca2+) concentrations, and Na+, K+-ATPase enzyme activity in gill tissue. Mussels accumulated Pb rapidly, with tissue concentrations increasing at an exposure-dependent rate for the first 2 weeks, but with no significant increase from 2 to 4 weeks. Mussel tissue Pb concentrations ranged from 0.34 to 898 mu g/g dry weight, were strongly related to Pb in test water at every time interval (7, 14, 21, and 28 days), and did not significantly increase after day 14. Hemolymph Pb concentration was variable, dependent on exposure concentration, and showed no appreciable change with time beyond day 7, except for mussels in the greatest exposure concentration (245 mu g/L), which showed a significant reduction in Pb by 28 days, suggesting a threshold for Pb binding or elimination in hemolymph at concentrations near 1000 mu g/g. The Na+, K+-ATPase activity in the gill tissue of mussels was significantly reduced by Pb on day 28 and was highly correlated with tissue Pb concentration (R2 = 0.92; P = 0.013). The Na+, K+-ATPase activity was correlated with reduced hemolymph Na+ concentration at the greatest Pb exposure when enzyme activity was at 30% of controls. Hemolymph Ca2+ concentration increased significantly in mussels from the greatest Pb exposure and may be due to remobilization from the shell in an attempt to buffer the hemolymph against Pb uptake and toxicity. We conclude that Na+, K+-ATPase activity in mussels was adversely affected by Pb exposure, however, because the effects on activity were variable at the lower test concentrations, additional research is warranted over this range of exposures. (C) 2010 Wiley Periodicals, Inc. Environ Toxicol, 2012.

What is the potential for interventions designed to prevent violence against women to reduce children's exposure to violence? Findings from the SASA! study, Kampala, Uganda.

PubMed

Kyegombe, Nambusi; Abramsky, Tanya; Devries, Karen M; Michau, Lori; Nakuti, Janet; Starmann, Elizabeth; Musuya, Tina; Heise, Lori; Watts, Charlotte

2015-12-01

Intimate partner violence (IPV) and child maltreatment often co-occur in households and lead to negative outcomes for children. This article explores the extent to which SASA!, an intervention to prevent violence against women, impacted children's exposure to violence. Between 2007 and 2012 a cluster randomized controlled trial was conducted in Kampala, Uganda. An adjusted cluster-level intention to treat analysis, compares secondary outcomes in intervention and control communities at follow-up. Under the qualitative evaluation, 82 in-depth interviews were audio recorded at follow-up, transcribed verbatim, and analyzed using thematic analysis complemented by constant comparative methods. This mixed-methods article draws mainly on the qualitative data. The findings suggest that SASA! impacted on children's experience of violence in three main ways. First, quantitative data suggest that children's exposure to IPV was reduced. We estimate that reductions in IPV combined with reduced witnessing by children when IPV did occur, led to a 64% reduction in prevalence of children witnessing IPV in their home (aRR 0.36, 95% CI 0.06-2.20). Second, among couples who experienced reduced IPV, qualitative data suggests parenting and discipline practices sometimes also changed-improving parent-child relationships and for a few parents, resulting in the complete rejection of corporal punishment as a disciplinary method. Third, some participants reported intervening to prevent violence against children. The findings suggest that interventions to prevent IPV may also impact on children's exposure to violence, and improve parent-child relationships. They also point to potential synergies for violence prevention, an area meriting further exploration. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Hypoxia-Related Hormonal Appetite Modulation in Humans during Rest and Exercise: Mini Review

PubMed Central

Debevec, Tadej

2017-01-01

Obesity is associated with numerous chronic ailments and represents one of the major health and economic issues in the modernized societies. Accordingly, there is an obvious need for novel treatment approaches. Recently, based on the reports of reduced appetite and subsequent weight loss following high-altitude sojourns, exposure to hypoxia has been proposed as a viable weight-reduction strategy. While altitude-related appetite modulation is complex and not entirely clear, hypoxia-induced alterations in hormonal appetite modulation might be among the key underlying mechanisms. The present paper summarizes the up-to-date research on hypoxia/altitude-induced changes in the gut and adipose tissue derived peptides related to appetite regulation. Orexigenic hormone ghrelin and anorexigenic peptides leptin, glucagon-like peptide-1, peptide YY, and cholecystokinin have to-date been investigated as potential modulators of hypoxia-driven appetite alterations. Current evidence suggests that hypoxia can, especially acutely, lead to decreased appetite, most probably via reduction of acylated ghrelin concentration. Hypoxia-related short and long-term changes in other hormonal markers are more unclear although hypoxia seems to importantly modulate leptin levels, especially following prolonged hypoxic exposures. Limited evidence also suggests that different activity levels during exposures to hypoxia do not additively affect hormonal appetite markers. Although very few studies have been performed in obese/overweight individuals, the available data indicate that hypoxia/altitude exposures do not seem to differentially affect appetite regulation via hormonal pathways in this cohort. Given the lack of experimental data, future well-controlled acute and prolonged studies are warranted to expand our understanding of hypoxia-induced hormonal appetite modulation and its kinetics in health and disease. PMID:28611686

Impact of the California lead ammunition ban on reducing lead exposure in golden eagles and turkey vultures.

PubMed

Kelly, Terra R; Bloom, Peter H; Torres, Steve G; Hernandez, Yvette Z; Poppenga, Robert H; Boyce, Walter M; Johnson, Christine K

2011-04-06

Predatory and scavenging birds may be exposed to high levels of lead when they ingest shot or bullet fragments embedded in the tissues of animals injured or killed with lead ammunition. Lead poisoning was a contributing factor in the decline of the endangered California condor population in the 1980s, and remains one of the primary factors threatening species recovery. In response to this threat, a ban on the use of lead ammunition for most hunting activities in the range of the condor in California was implemented in 2008. Monitoring of lead exposure in predatory and scavenging birds is essential for assessing the effectiveness of the lead ammunition ban in reducing lead exposure in these species. In this study, we assessed the effectiveness of the regulation in decreasing blood lead concentration in two avian sentinels, golden eagles and turkey vultures, within the condor range in California. We compared blood lead concentration in golden eagles and turkey vultures prior to the lead ammunition ban and one year following implementation of the ban. Lead exposure in both golden eagles and turkey vultures declined significantly post-ban. Our findings provide evidence that hunter compliance with lead ammunition regulations was sufficient to reduce lead exposure in predatory and scavenging birds at our study sites.

Impact of the California Lead Ammunition Ban on Reducing Lead Exposure in Golden Eagles and Turkey Vultures

PubMed Central

Kelly, Terra R.; Bloom, Peter H.; Torres, Steve G.; Hernandez, Yvette Z.; Poppenga, Robert H.; Boyce, Walter M.; Johnson, Christine K.

2011-01-01

Predatory and scavenging birds may be exposed to high levels of lead when they ingest shot or bullet fragments embedded in the tissues of animals injured or killed with lead ammunition. Lead poisoning was a contributing factor in the decline of the endangered California condor population in the 1980s, and remains one of the primary factors threatening species recovery. In response to this threat, a ban on the use of lead ammunition for most hunting activities in the range of the condor in California was implemented in 2008. Monitoring of lead exposure in predatory and scavenging birds is essential for assessing the effectiveness of the lead ammunition ban in reducing lead exposure in these species. In this study, we assessed the effectiveness of the regulation in decreasing blood lead concentration in two avian sentinels, golden eagles and turkey vultures, within the condor range in California. We compared blood lead concentration in golden eagles and turkey vultures prior to the lead ammunition ban and one year following implementation of the ban. Lead exposure in both golden eagles and turkey vultures declined significantly post-ban. Our findings provide evidence that hunter compliance with lead ammunition regulations was sufficient to reduce lead exposure in predatory and scavenging birds at our study sites. PMID:21494329

Development of Anxiety-Like Behavior via Hippocampal IGF-2 Signaling in the Offspring of Parental Morphine Exposure: Effect of Enriched Environment

PubMed Central

Li, Chang-Qi; Luo, Yan-Wei; Bi, Fang-Fang; Cui, Tao-Tao; Song, Ling; Cao, Wen-Yu; Zhang, Jian-Yi; Li, Fang; Xu, Jun-Mei; Hao, Wei; Xing, Xiao-Wei; Zhou, Fiona H; Zhou, Xin-Fu; Dai, Ru-Ping

2014-01-01

Opioid addiction is a major social, economic, and medical problem worldwide. Long-term adverse consequences of chronic opiate exposure not only involve the individuals themselves but also their offspring. Adolescent maternal morphine exposure results in behavior and morphologic changes in the brain of their adult offspring. However, few studies investigate the effect of adult opiate exposure on their offspring. Furthermore, the underlying molecular signals regulating the intergenerational effects of morphine exposure are still elusive. We report here that morphine exposure of adult male and female rats resulted in anxiety-like behavior and dendritic retraction in the dentate gyrus (DG) region of the hippocampus in their adult offspring. The behavior and morphologic changes were concomitant with the downregulation of insulin-like growth factor (IGF)-2 signaling in the granular zone of DG. Overexpression of hippocampal IGF-2 by bilateral intra-DG injection of lentivirus encoding the IGF-2 gene prevented anxiety-like behaviors in the offspring. Furthermore, exposure to an enriched environment during adolescence corrected the reduction of hippocampal IGF-2 expression, normalized anxiety-like behavior and reversed dendritic retraction in the adult offspring. Thus, parental morphine exposure can lead to the downregulation of hippocampal IGF-2, which contributed to the anxiety and hippocampal dendritic retraction in their offspring. An adolescent-enriched environment experience prevented the behavior and morphologic changes in their offspring through hippocampal IGF-2 signaling. IGF-2 and an enriched environment may be a potential intervention to prevention of anxiety and brain atrophy in the offspring of parental opioid exposure. PMID:24889368

Development and application of a long dynamic range nitrous oxide monitoring system.

PubMed

Ward, B G

1985-12-01

The laboratory and field evaluation of a nitrous oxide monitor for an extremely wide range of cumulative exposures are reviewed. The passive sampling behavior and high analyte capacity show it to be useful for short-term and full workweek exposure monitoring. The monitor has application for both area and personnel surveillance. The principal criterion is for an accurate report of exposure time of the monitor. Application of the monitor to real workplace environments--with and without a reference method--demonstrated the ability of workweek monitoring as a valuable and potentially superior way of documenting exposure stress of employees. Environmental factors such as humidity and temperature variation are shown to have acceptably small effects on both short- and long-term exposure data; barometric pressure affects the data in a predictable manner. Paired dosimeters show good agreement in the workplace environment throughout the range of 6-40 cumulative hours of exposure. In both hospital and dental operating suites, work logistics and work group relationships were readily traceable on a week-by-week basis during a continuous weekly monitoring program. Source emissions and appropriate worker and work area exposure relationships were clearly evident, with appropriate reduction of all exposures as a result of an abbreviated work schedule. The ability to effectively track employee and area exposure excursions in an integrated weekly manner leads to a whole series of new applications and concepts of industrial hygiene surveillance. Such approaches could effectively replace the speculative statistical approaches currently in use with actual data on a cost effective basis.

Lead exposures and biological responses in military weapons systems: Aerosol characteristics and acute lead effects among US Army artillerymen: Final report

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

Bhattacharyya, M.H.; Stebbings, J.H.; Peterson, D.P.

1993-03-01

This study was to determine the concentration and chemical nature of lead (Pb) aerosols produced during the firing of artillery and to determine the exposures and biological responses of crew members exposed to lead aerosols during such firing. The concentrations of lead-containing aerosols at crew positions depended on wind conditions, with higher concentrations when firing into a head wind. Aerosol concentrations were highest in the muzzle blast zone. Concentrations of lead in the blood of crew members rose during the first 12 days of exposure to elevated airborne lead concentrations and then leveled off. There was no rapid decrease inmore » blood lead concentrations after completion of firing. Small decreases in hematocrit and small increases in free erythrocyte porphyrin were correlated with increasing exposure to airborne lead. These changes were reversed by seven weeks after firing. Changes in nerve conduction velocity had borderline statistical significance to airborne lead exposure. In measuring nerve conduction velocity, differences in skin temperature must be taken into account.« less

Environmental exposures to lead and cadmium measured in human placenta.

PubMed

Falcón, María; Viñas, Pilar; Osuna, Eduardo; Luna, Aurelio

2002-01-01

Pregnant women exposed to even low levels of environmental lead and cadmium may experience adverse perinatal effects. To evaluate the usefulness of the placenta for monitoring environmental lead and cadmium exposure, concentrations of both metals were measured in placentas (n = 86) with atomic absorption spectrometry. Environmental exposure was assessed in accordance with the degree of industrial activity and transport pollution near the places of residence. The authors found significantly higher lead and cadmium levels in placentas of women living in urban-industrial areas than in placentas of women living in rural areas. Lead concentrations in placenta reflect environmental exposures; smoking during gestation explained a large portion of placental cadmium. This finding suggests that when a pregnant woman is a heavy smoker, tobacco exposure masks environmental cadmium exposure, especially in areas with low levels of cadmium pollution.

Tissue lead concentration during chronic exposure of Pimephales promelas (fathead minnow) to lead nitrate in aquarium water.

PubMed

Spokas, Eric G; Spur, Bernd W; Smith, Holly; Kemp, Francis W; Bogden, John D

2006-11-01

The fathead minnow is a useful species for evaluating the toxicity of wastewater effluents. While this fish is widely used for "survival" studies of metal toxicity, little or no work has been done on the tissue distribution of metals in fathead minnows. To determine the distribution of tissue lead, aquarium studies were conducted for several weeks with fish maintained in soft synthetic freshwater. Lead- (II) nitrate was added to three aquaria attaining concentrations of 20-30 ppb (aquarium B), 100-140 ppb (aquarium C), and roughly 200 ppb (aquarium D). Results were compared to controls (aquarium A). During the initial week, the majority of aquarium D fish died, whereas few deaths occurred in the other groups. Lead accumulation was dose- and tissue-dependent, with highest uptake by the gills. Gill concentrations of aquarium D fish averaged about 4-fold higherthan in skeleton or skin and muscle. In vitro, lead (2.5-25 ppm) caused dose-dependent reductions in the ratio of reduced glutathione/oxidized glutathione (GSH/GSSG) in gills incubated in physiological buffer. These findings demonstrate that fathead minnow gills bind and accumulate waterborne lead rapidly and preferentially and raise the possibility that gill lipid peroxidation contributes to lead toxicity at low water hardness.

78 FR 38730 - Announcement of Funding Awards for Lead-Based Paint Hazard Control, and Lead Hazard Reduction...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-27

... Awards for Lead-Based Paint Hazard Control, and Lead Hazard Reduction Demonstration Grant Programs for... (OHHLHC) Lead-Based Paint Hazard Control, and Lead Hazard Reduction Demonstration Grant Program Notices of... Grants.gov on December 3, 2012, and amended on January 18, 2013, for the Lead Based Paint Hazard Control...

Childhood Lead Exposure from Battery Recycling in Vietnam

PubMed Central

Van Tung, Lo; Wallace, Ryan M.; Havens, Deborah J.; Karr, Catherine J.; Bich Diep, Nguyen; Croteau, Gerry A.; Beaudet, Nancy J.; Duy Bao, Nguyen

2015-01-01

Background. Battery recycling facilities in developing countries can cause community lead exposure. Objective. To evaluate child lead exposure in a Vietnam battery recycling craft village after efforts to shift home-based recycling outside the village. Methods. This cross-sectional study evaluated 109 children in Dong Mai village, using blood lead level (BLL) measurement, parent interview, and household observation. Blood samples were analyzed with a LeadCare II field instrument; highest BLLs (≥45 μg/dL) were retested by laboratory analysis. Surface and soil lead were measured at 11 households and a school with X-ray fluorescence analyzer. Results. All children had high BLLs; 28% had BLL ≥45 μg/dL. Younger age, family recycling, and outside brick surfaces were associated with higher BLL. Surface and soil lead levels were high at all tested homes, even with no recycling history. Laboratory BLLs were lower than LeadCare BLLs, in 24 retested children. Discussion. In spite of improvements, lead exposure was still substantial and probably associated with continued home-based recycling, legacy contamination, and workplace take-home exposure pathways. There is a need for effective strategies to manage lead exposure from battery recycling in craft villages. These reported BLL values should be interpreted cautiously, although the observed field-laboratory discordance may reflect bias in laboratory results. PMID:26587532

Childhood Lead Exposure from Battery Recycling in Vietnam.

PubMed

Daniell, William E; Van Tung, Lo; Wallace, Ryan M; Havens, Deborah J; Karr, Catherine J; Bich Diep, Nguyen; Croteau, Gerry A; Beaudet, Nancy J; Duy Bao, Nguyen

2015-01-01

Battery recycling facilities in developing countries can cause community lead exposure. To evaluate child lead exposure in a Vietnam battery recycling craft village after efforts to shift home-based recycling outside the village. This cross-sectional study evaluated 109 children in Dong Mai village, using blood lead level (BLL) measurement, parent interview, and household observation. Blood samples were analyzed with a LeadCare II field instrument; highest BLLs (≥45 μg/dL) were retested by laboratory analysis. Surface and soil lead were measured at 11 households and a school with X-ray fluorescence analyzer. All children had high BLLs; 28% had BLL ≥45 μg/dL. Younger age, family recycling, and outside brick surfaces were associated with higher BLL. Surface and soil lead levels were high at all tested homes, even with no recycling history. Laboratory BLLs were lower than LeadCare BLLs, in 24 retested children. In spite of improvements, lead exposure was still substantial and probably associated with continued home-based recycling, legacy contamination, and workplace take-home exposure pathways. There is a need for effective strategies to manage lead exposure from battery recycling in craft villages. These reported BLL values should be interpreted cautiously, although the observed field-laboratory discordance may reflect bias in laboratory results.

Relative tolerance of a range of Australian native plant species and lettuce to copper, zinc, cadmium, and lead.

PubMed

Lamb, Dane T; Ming, Hui; Megharaj, Mallavarapu; Naidu, Ravi

2010-10-01

The tolerance of wild flora to heavy-metal exposure has received very little research. In this study, the tolerance of four native tree species, four native grass species, and lettuce to copper (Cu), zinc (Zn), cadmium (Cd), and lead (Pb) was investigated in a root-elongation study using Petri dishes. The results of these studies show a diverse range of responses to Cu, Zn, Cd, and Pb amongst the tested plant species. Toxicity among metals decreased in the following order: Cd ~ Cu > Pb > Zn. Metal concentrations resulting in a 50% reduction in growth (EC(50)) varied considerably, ranging from (microM) 30 (Dichanthium sericeum) to >2000 (Acacia spp.) for Cu; from 260 (Lactuca sativa) to 2000 (Acacia spp.) for Zn; from 27 (L. sativa) to 940 (Acacia holosericea) for Cd; and from 180 (L. sativa) to >1000 (Acacia spp.) for Pb. Sensitive native plant species identified included D. sericeum, Casuarina cunninghamiana, and Austrodanthonia caespitosa. However, L. sativa (lettuce) was also among the most sensitive to all four metals. Acacia species showed a high tolerance to metal exposure, suggesting that the Acacia genus shows potential for use in contaminated-site revegetation.

The Effect of D-cycloserine on Subliminal Cue Exposure in Spider Fearful Individuals

PubMed Central

Gutner, Cassidy A.; Weinberger, Joel; Hofmann, Stefan G.

2012-01-01

Research on d-cycloserine (DCS) has demonstrated a significant effect on symptom reduction in human studies that utilized conventional exposure-based approaches. Recent studies have offered promising results for targeting fears through subliminal paradigms. In this double-blind, randomized placebo controlled study, 45 spider fearful individuals received DCS or placebo pills prior to completing a subliminal cue exposure task to images of spiders. Participants completed self-report questionnaires and a behavioral approach task to a live caged tarantula. After repeated exposure to subliminal spider cues, participants in the DCS group reported a greater reduction in disgust than individuals in the placebo group. No difference was observed in fear ratings. These findings suggest that DCS augments the reduction in disgust in spider fearful subjects after subliminal exposure to spider cues. PMID:22992160

Reduction in radiation exposure to nursing personnel with the use of remote afterloading brachytherapy devices

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

Grigsby, P.W.; Perez, C.A.; Eichling, J.

The radiation exposure to nursing personnel from patients with brachytherapy implants on a large brachytherapy service were reviewed. Exposure to nurses, as determined by TLD monitors, indicates a 7-fold reduction in exposure after the implementation of the use of remote afterloading devices. Quarterly TLD monitor data for six quarters prior to the use of remote afterloading devices demonstrate an average projected annual dose equivalent to the nurses of 152 and 154 mrem (1.5 mSv). After the implementation of the remote afterloading devices, the quarterly TLD monitor data indicate an average dose equivalent per nurse of 23 and 19 mrem (0.2more » mSv). This is an 87% reduction in exposure to nurses with the use of these devices (p less than 0.01).« less

Childhood Lead Poisoning in the '90s.

ERIC Educational Resources Information Center

Piomelli, Sergio

1994-01-01

Notes that, despite gains in eliminating lead sources, there are still detectable effects from low-level exposure. Discusses at what level of exposure the adverse effects of lead become trivial and what measures, if any, should be taken to reduce low-level exposure. (HTH)

Exogenous retinoic acid induces digit reduction in opossums (Monodelphis domestica) by disrupting cell death and proliferation, and apical ectodermal ridge and zone of polarizing activity function.

PubMed

Molineaux, Anna C; Maier, Jennifer A; Schecker, Teresa; Sears, Karen E

2015-03-01

Retinoic acid (RA) is a vitamin A derivative. Exposure to exogenous RA generates congenital limb malformations (CLMs) in species from frogs to humans. These CLMs include but are not limited to oligodactyly and long-bone hypoplasia. The processes by which exogenous RA induces CLMs in mammals have been best studied in mouse, but as of yet remain unresolved. We investigated the impact of exogenous RA on the cellular and molecular development of the limbs of a nonrodent model mammal, the opossum Monodelphis domestica. Opossums exposed to exogenous retinoic acid display CLMs including oligodactly, and results are consistent with opossum development being more susceptible to RA-induced disruptions than mouse development. Exposure of developing opossums to exogenous RA leads to an increase in cell death in the limb mesenchyme that is most pronounced in the zone of polarizing activity, and a reduction in cell proliferation throughout the limb mesenchyme. Exogenous RA also disrupts the expression of Shh in the zone of polarizing activity, and Fgf8 in the apical ectodermal ridge, and other genes with roles in the regulation of limb development and cell death. Results are consistent with RA inducing CLMs in opossum limbs by disrupting the functions of the apical ectodermal ridge and zone of polarizing activity, and driving an increase in cell death and reduction of cell proliferation in the mesenchyme of the developing limb. © 2015 Wiley Periodicals, Inc.

The intersection of aggregate-level lead exposure and crime.

PubMed

Boutwell, Brian B; Nelson, Erik J; Emo, Brett; Vaughn, Michael G; Schootman, Mario; Rosenfeld, Richard; Lewis, Roger

2016-07-01

Childhood lead exposure has been associated with criminal behavior later in life. The current study aimed to analyze the association between elevated blood lead levels (n=59,645) and crime occurrence (n=90,433) across census tracts within St. Louis, Missouri. Longitudinal ecological study. Saint Louis, Missouri. Blood lead levels. Violent, Non-violent, and total crime at the census tract level. Spatial statistical models were used to account for the spatial autocorrelation of the data. Greater lead exposure at the census-tract level was associated with increased violent, non-violent, and total crime. In addition, we examined whether non-additive effects existed in the data by testing for an interaction between lead exposure and concentrated disadvantage. Some evidence of a negative interaction emerged, however, it failed to reach traditional levels of statistical significance (supplementary models, however, revealed a similar negative interaction that was significant). More precise measurements of lead exposure in the aggregate, produced additional evidence that lead is a potent predictor of criminal outcomes. Copyright © 2016 Elsevier Inc. All rights reserved.

Chronic lead exposure induces cochlear oxidative stress and potentiates noise-induced hearing loss.

PubMed

Jamesdaniel, Samson; Rosati, Rita; Westrick, Judy; Ruden, Douglas M

2018-08-01

Acquired hearing loss is caused by complex interactions of multiple environmental risk factors, such as elevated levels of lead and noise, which are prevalent in urban communities. This study delineates the mechanism underlying lead-induced auditory dysfunction and its potential interaction with noise exposure. Young-adult C57BL/6 mice were exposed to: 1) control conditions; 2) 2 mM lead acetate in drinking water for 28 days; 3) 90 dB broadband noise 2 h/day for two weeks; and 4) both lead and noise. Blood lead levels were measured by inductively coupled plasma mass spectrometry analysis (ICP-MS) lead-induced cochlear oxidative stress signaling was assessed using targeted gene arrays, and the hearing thresholds were assessed by recording auditory brainstem responses. Chronic lead exposure downregulated cochlear Sod1, Gpx1, and Gstk1, which encode critical antioxidant enzymes, and upregulated ApoE, Hspa1a, Ercc2, Prnp, Ccl5, and Sqstm1, which are indicative of cellular apoptosis. Isolated exposure to lead or noise induced 8-12 dB and 11-25 dB shifts in hearing thresholds, respectively. Combined exposure induced 18-30 dB shifts, which was significantly higher than that observed with isolated exposures. This study suggests that chronic exposure to lead induces cochlear oxidative stress and potentiates noise-induced hearing impairment, possibly through parallel pathways. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Calibrating a population-based job-exposure matrix using inspection measurements to estimate historical occupational exposure to lead for a population-based cohort in Shanghai, China

PubMed Central

Koh, Dong-Hee; Bhatti, Parveen; Coble, Joseph B.; Stewart, Patricia A; Lu, Wei; Shu, Xiao-Ou; Ji, Bu-Tian; Xue, Shouzheng; Locke, Sarah J.; Portengen, Lutzen; Yang, Gong; Chow, Wong-Ho; Gao, Yu-Tang; Rothman, Nathaniel; Vermeulen, Roel; Friesen, Melissa C.

2012-01-01

The epidemiologic evidence for the carcinogenicity of lead is inconsistent and requires improved exposure assessment to estimate risk. We evaluated historical occupational lead exposure for a population-based cohort of women (n=74,942) by calibrating a job-exposure matrix (JEM) with lead fume (n=20,084) and lead dust (n=5,383) measurements collected over four decades in Shanghai, China. Using mixed-effect models, we calibrated intensity JEM ratings to the measurements using fixed-effects terms for year and JEM rating. We developed job/industry-specific estimates from the random-effects terms for job and industry. The model estimates were applied to subjects’ jobs when the JEM probability rating was high for either job or industry; remaining jobs were considered unexposed. The models predicted that exposure increased monotonically with JEM intensity rating and decreased 20–50-fold over time. The cumulative calibrated JEM estimates and job/industry-specific estimates were highly correlated (Pearson correlation=0.79–0.84). Overall, 5% of the person-years and 8% of the women were exposed to lead fume; 2% of the person-years and 4% of the women were exposed to lead dust. The most common lead-exposed jobs were manufacturing electronic equipment. These historical lead estimates should enhance our ability to detect associations between lead exposure and cancer risk in future epidemiologic analyses. PMID:22910004

Recovery of lead from lead paste in spent lead acid battery by hydrometallurgical desulfurization and vacuum thermal reduction.

PubMed

Ma, Yunjian; Qiu, Keqiang

2015-06-01

Lead sulfate, lead oxides and lead metal are the main component of lead paste in spent lead acid battery. When lead sulfate was desulfurized and transformed into lead carbonate by sodium carbonate, lead metal and lead oxides remained unchanged. Lead carbonate is easily decomposed to lead oxide and carbon dioxide under high temperature. Namely, vacuum thermal process is the reduction reaction of lead oxides. A compatible environmental process consisted of hydrometallurgical desulfurization and vacuum thermal reduction to recycle lead was investigated in this research. Lead paste was firstly desulfurized with sodium carbonate, by which, the content of sulfur declined from 7.87% to 0.26%. Then, the desulfurized lead paste was reduced by charcoal under vacuum. Under the optimized reaction conditions, i.e., vacuum thermal reduction at temperature 850°C under 20 Pa for 45 min, a 22.11×10(-2) g cm(-2) min(-1) reduction rate, and a 98.13% direct recovery ratio of fine lead (99.77%) had been achieved, respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

Reducing health risks from indoor exposures in rapidly developing urban China.

PubMed

Zhang, Yinping; Mo, Jinhan; Weschler, Charles J

2013-07-01

Over the past two decades there has been a large migration of China's population from rural to urban regions. At the same time, residences in cities have changed in character from single-story or low-rise buildings to high-rise structures constructed and furnished with many synthetic materials. As a consequence, indoor exposures (to pollutants with outdoor and indoor sources) have changed significantly. We briefly discuss the inferred impact that urbanization and modernization have had on indoor exposures and public health in China. We argue that growing adverse health costs associated with these changes are not inevitable, and we present steps that could be taken to reduce indoor exposures to harmful pollutants. As documented by China's Ministry of Health, there have been significant increases in morbidity and mortality among urban residents over the past 20 years. Evidence suggests that the population's exposure to air pollutants has contributed to increases in lung cancer, cardiovascular disease, pulmonary disease, and birth defects. Whether a pollutant has an outdoor or an indoor source, most exposure to the pollutant occurs indoors. Going forward, indoor exposures can be reduced by limiting the ingress of outdoor pollutants (while providing adequate ventilation with clean air), minimizing indoor sources of pollutants, updating government policies related to indoor pollution, and addressing indoor air quality during a building's initial design. Taking the suggested steps could lead to significant reductions in morbidity and mortality, greatly reducing the societal costs associated with pollutant derived ill health.

A Meta-Analysis of Observational Studies of the Association Between Chronic Occupational Exposure to Lead and Amyotrophic Lateral Sclerosis

PubMed Central

Gomes, James; Cashman, Neil R.; Little, Julian; Krewski, Daniel

2014-01-01

Objective: The association between occupational exposure to lead and amyotrophic lateral sclerosis (ALS) was examined through systematic review and meta-analyses of relevant epidemiological studies and reported according to PRISMA guidelines. Methods: Relevant studies were searched in multiple bibliographic databases through September 2013; additional articles were tracked through PubMed until submission. All records were screened in DistillerSR, and the data extracted from included articles were synthesized with meta-analysis. Results: The risk of developing ALS among individuals with a history of exposure to lead was almost doubled (odds ratio, 1.81; 95% confidence interval, 1.39 to 2.36) on the basis of nine included case-control studies with specific lead exposure information, with no apparent heterogeneity across included studies (I2 = 14%). The attributable risk of ALS because of exposure to lead was estimated to be 5%. Conclusions: Previous exposure to lead may be a risk factor for ALS. PMID:25479292

Acute effects on pulmonary function in young healthy adults exposed to traffic-related air pollution in semi-closed transport hub in Beijing.

PubMed

Huang, Jing; Deng, Furong; Wu, Shaowei; Zhao, Yan; Shima, Masayuki; Guo, Bin; Liu, Qichen; Guo, Xinbiao

2016-09-01

Transport hub is an important part of urban comprehensive transportation system. Traffic-related air pollution can reach high level because of difficulty of diffusion and increase of emission in transport hub. However, whether exposure in this semi-closed traffic micro-environment causes acute changes in pulmonary function of commuters still needs to be explored. Forty young healthy adults participated in this randomized, crossover study. Each participant underwent 2 h exposure in a designated transport hub and, on a separate occasion, in an appointed park. Personal exposures to fine particulate matter (PM 2.5 ), black carbon (BC) and carbon monoxide (CO) were measured. Forced expiratory volume in 1 s (FEV 1 ) and peak expiratory flow (PEF) were assessed pre-, during and post-exposure. Mixed linear models were used to analyze the pulmonary effects of traffic-related air pollutants. Participants had significantly higher exposures to PM 2.5 , BC and CO in the transport hub than in the park. Exposure in transport hub induced significant reductions in FEV 1 and PEF compared with the park during exposure 1 and 2 h. The reductions were significant associated with traffic-related air pollutants. For instance, per 10 μg/m 3 increment in PM 2.5 was associated with -0.15 % (95 % CI -0.28, -0.02 %) reduction in FEV 1 during exposure 2 h. However, effects became attenuate after 2 h exposure. Short-term exposure in transport hub had acute reduction effects on pulmonary function. More attention should be paid to the health effects of exposure in the semi-closed traffic micro-environment.

Lead hazards for pregnant women and children: part 1: immigrants and the poor shoulder most of the burden of lead exposure in this country. Part 1 of a two-part article details how exposure happens, whom it affects, and the harm it can do.

PubMed

Cleveland, Lisa M; Minter, Monica L; Cobb, Kathleen A; Scott, Anthony A; German, Victor F

2008-10-01

Poor, urban, and immigrant populations are at far greater risk for lead exposure than are other groups in the United States. Children with even slightly elevated blood lead levels are at increased risk for significant neurobehavioral problems that can extend through adolescence. Research has shown that elevated blood lead levels in pregnant women, even those well below 10 micrograms per deciliter-the Centers for Disease Control and Prevention's "level of concern"-can cause miscarriage, premature birth, low birth weight, and subsequent developmental delays in their children. Despite these well-established dangers, routine prenatal lead screening and lead education is not a standard of care. Part 1 of this two-part article presents a short case example of a pregnant mother with lead poisoning and describes the epidemiology of lead exposure in the United States, the main sources of lead exposure, and the effects of lead on the pregnant mother and the developing fetus and child. Prevention is crucial. Treatment options such as chelation must be used selectively and will not reverse damage once it's occurred. Part 2 will describe recommendations for screening, education, nutrition, reducing environmental exposures, and treatment.

Assessment of blood lead level declines in an area of historical mining with a holistic remediation and abatement program.

PubMed

Schoof, Rosalind A; Johnson, Dina L; Handziuk, Emma R; Landingham, Cynthia Van; Feldpausch, Alma M; Gallagher, Alexa E; Dell, Linda D; Kephart, Amy

2016-10-01

Lead exposure and blood lead levels (BLLs) in the United States have declined dramatically since the 1970s as many widespread lead uses have been discontinued. Large scale mining and mineral processing represents an additional localized source of potential lead exposure in many historical mining communities, such as Butte, Montana. After 25 years of ongoing remediation efforts and a residential metals abatement program that includes blood lead monitoring of Butte children, examination of blood lead trends offers a unique opportunity to assess the effectiveness of Butte's lead source and exposure reduction measures. This study examined BLL trends in Butte children ages 1-5 (n= 2796) from 2003-2010 as compared to a reference dataset matched for similar demographic characteristics over the same period. Blood lead differences across Butte during the same period are also examined. Findings are interpreted with respect to effectiveness of remediation and other factors potentially contributing to ongoing exposure concerns. BLLs from Butte were compared with a reference dataset (n=2937) derived from the National Health and Nutrition Examination Survey. The reference dataset was initially matched for child age and sample dates. Additional demographic factors associated with higher BLLs were then evaluated. Weights were applied to make the reference dataset more consistent with the Butte dataset for the three factors that were most disparate (poverty-to-income ratio, house age, and race/ethnicity). A weighted linear mixed regression model showed Butte geometric mean BLLs were higher than reference BLLs for 2003-2004 (3.48vs. 2.05µg/dL), 2005-2006 (2.65vs. 1.80µg/dL), and 2007-2008 (2.2vs. 1.72µg/dL), but comparable for 2009-2010 (1.53vs. 1.51µg/dL). This trend suggests that, over time, the impact of other factors that may be associated with Butte BLLs has been reduced. Neighborhood differences were examined by dividing the Butte dataset into the older area called "Uptown", located at higher elevation atop historical mine workings, and "the Flats", at lower elevation and more recently developed. Significant declines in BLLs were observed over time in both areas, though Uptown had slightly higher BLLs than the Flats (2003-2004: 3.57vs. 3.45µg/dL, p=0.7; 2005-2006: 2.84vs. 2.52µg/dL, p=0.1; 2007-2008: 2.58vs. 1.99µg/dL, p=0.001; 2009-2010: 1.71vs. 1.44µg/dL, p=0.02). BLLs were higher when tested in summer/fall than in winter/spring for both neighborhoods, and statistically higher BLLs were found for children in Uptown living in properties built before 1940. Neighborhood differences and the persistence of a greater percentage of high BLLs (>5µg/dL) in Butte vs. the reference dataset support continuation of the home lead abatement program. Butte BLL declines likely reflect the cumulative effectiveness of screening efforts, community-wide remediation, and the ongoing metals abatement program in Butte in addition to other factors not accounted for by this study. As evidenced in Butte, abatement programs that include home evaluations and assistance in addressing multiple sources of lead exposure can be an important complement to community-wide soil remediation activities. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Feedback on Measured Dust Concentrations Reduces Exposure Levels Among Farmers.

PubMed

Basinas, Ioannis; Sigsgaard, Torben; Bønløkke, Jakob Hjort; Andersen, Nils Testrup; Omland, Øyvind; Kromhout, Hans; Schlünssen, Vivi

2016-08-01

The high burden of exposure to organic dust among livestock farmers warrants the establishment of effective preventive and exposure control strategies for these workers. The number of intervention studies exploring the effectiveness of exposure reduction strategies through the use of objective measurements has been limited. To examine whether dust exposure can be reduced by providing feedback to the farmers concerning measurements of the exposure to dust in their farm. The personal dust levels of farmers in 54 pig and 26 dairy cattle farms were evaluated in two measurement series performed approximately 6 months apart. Detailed information on work tasks and farm characteristics during the measurements were registered. Participating farms were randomized a priori to a control (n = 40) and an intervention group (n = 40). Shortly after the first visit, owners of intervention farms only received a letter with information on the measured dust concentrations in the farm together with some general advises on exposure reduction strategies (e.g. use of respirators during certain tasks). Relationships between measured dust concentrations and intervention status were quantified by means of linear mixed effect analysis with farm and worker id as random effects. Season, type of farming, and work tasks were treated as fixed effects. Changes in exposure over time were explored primarily at a farm level in models combined, as well as separate for pig and cattle farmers. After adjustment for fixed effects, an overall reduction of 23% in personal dust exposures was estimated as a result of the intervention (P = 0.02). Exposure reductions attributable to the intervention were similar across pig and cattle farmers, but statistically significant only for pig farmers. Intervention effects among pig farmers did not depend on the individuals' information status; but among cattle farmers a significant 48% reduction in exposure was found only among individuals that reported to have been informed. No systematic differences in changes over time considering the use of respiratory protection between the intervention and control groups were observed. The results of the present study suggest reductions between 20 and 30% in personal exposure to inhalable dust to be feasible through simple information provided to the farm owners regarding actual levels of exposure together with instructions on basic measures of prevention. The exact reasons for these effects are unclear, but likely they involve changes in behavior and working practices among intervention farmers. © The Author 2016. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

[Urban individual exposure to cadmium and baroreceptor response to posture].

PubMed

Sancini, A; Sinibaldi, F; Loreti, B; De Sio, S; Casale, T; Sacco, C; Scala, B; Monti, C; Chighine, A; Bonomi, S; Cirelli, P; Massimi, R; Giubilati, R; Tomei, F; Rosati, M V

2014-01-01

Outdoor workers are daily exposed to urban pollutants. The aim of the study is to evaluate the relationship between the values of environmental monitoring collected by personal dosimetries and changes in blood pressure due to posture in outdoor workers. 32 subjects of both sexes were enrolled in the study, we evaluated the values of environmental monitoring of breathable dust, nickel, arsenic, cadmium, lead, benzene, toluene, xylene and 16 PAHs. Blood pressure in supine and standing positions was measured in all subjects. The multiple linear regression analysis showed a significant reduction of orthostatic response of diastolic blood pressure in non-smoking outdoor workers occupationally exposed to cadmium. The results of our study let us to believe that exposure to low doses of urban polluted cadmium may affect the response of diastolic blood pressure to orthostatism, as per a paraphysiological condition of sympathetic down-regulation.

Lead Levels in Landfill Areas and Childhood Exposure: An Integrative Review.

PubMed

Kim, M Angela; Williams, Kimberly A

2017-01-01

Landfills are high-risk areas for environmental lead exposure for children living in poverty stricken areas in many countries. This review examines landfills and lead toxicity in children. The review discusses the effects of lead toxicity, provides evidenced based recommendations to reduce lead exposure, and identify gaps in the evidence. A database search was conducted of articles in English from 1985 to 2014. Ten articles met the inclusion criteria. The Whittemore and Knafl framework and the John Hopkins Research Evidence Appraisal Tool © were used for reviewing the data. Elevated blood lead levels (BLLs) of children living near landfills were related to increased soil lead levels. Toxic effects of lead included adverse outcomes such as encephalopathy or death for children. Different approaches to decrease lead level include environmental surveillance, BLL screening, and soil abatement which are costly. Increased BLL through environmental exposure is connected with poor health outcomes and death among children. Evidence-based prevention included monitoring and screening and costly soil abatement. It is recommended that future studies focus on community education for exposure avoidance for children living near landfill areas. © 2016 Wiley Periodicals, Inc.

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.

Risk-Reduction Strategies to Expand Radon Care Planning with Vulnerable Groups

PubMed Central

Larsson, Laura S.

2016-01-01

Objectives Radon is the second leading cause of lung cancer in the United States and the leading cause of lung cancer among nonsmokers. Residential radon is the cause of approximately 21,000 U.S. lung cancer deaths each year. Dangerous levels of radon are just as likely to be found in low-rise apartments and townhomes as single-family homes in the same area. The preferred radon mitigation strategy can be expensive and requires structural modifications to the home. The public health nurse (PHN) needs a collection of low-cost alternatives when working with low-income families or families who rent their homes. Method A review of the literature was performed to identify evidence-based methods to reduce radon risk with vulnerable populations. Results Fourteen recommendations for radon risk reduction were categorized into four strategies. Nine additional activities for raising awareness and increasing testing were also included. Discussion The results pair the PHN with practical interventions and the underlying rationale to develop radon careplans with vulnerable families across housing types. The PHN has both the competence and the access to help families reduce their exposure to this potent carcinogen. PMID:24547763

Risk-reduction strategies to expand radon care planning with vulnerable groups.

PubMed

Larsson, Laura S

2014-01-01

Radon is the second leading cause of lung cancer in the United States and the leading cause of lung cancer among nonsmokers. Residential radon is the cause of approximately 21,000 U.S. lung cancer deaths each year. Dangerous levels of radon are just as likely to be found in low-rise apartments and townhomes as single-family homes in the same area. The preferred radon mitigation strategy can be expensive and requires structural modifications to the home. The public health nurse (PHN) needs a collection of low-cost alternatives when working with low-income families or families who rent their homes. A review of the literature was performed to identify evidence-based methods to reduce radon risk with vulnerable populations. Fourteen recommendations for radon risk reduction were categorized into four strategies. Nine additional activities for raising awareness and increasing testing were also included. The results pair the PHN with practical interventions and the underlying rationale to develop radon careplans with vulnerable families across housing types. The PHN has both the competence and the access to help families reduce their exposure to this potent carcinogen. © 2014 Wiley Periodicals, Inc.

The effect of MRET polymer compound on SAR values of RF phones.

PubMed

Smirnov, Igor

2008-01-01

This article is related to the proposed hypothesis and experimental data regarding the ability of defined polar polymer compound (MRET polymer) applied to RF phones to increase the dielectric permittivity of water based solutions and to reduce the SAR (Specific Absorption Rate) values inside the "phantom head" filled with the jelly simulating muscle and brain tissues. Due to the high organizational state of fractal structures of MRET polymer compounds and the phenomenon of piezoelectricity, this polymer generates specific subtle, low frequency, non-coherent electromagnetic oscillations (optimal random field) that can affect the hydrogen lattice of the molecular structure of water and subsequently modify the electrodynamic properties of water. The increase of dielectric permittivity of water finally leads to the reduction of the absorption rate of the electromagnetic field by living tissue. The reduction of SAR values is confirmed by the research conducted in June - July of 2006 at RF Exposure Laboratory in Escondido, California. This test also confirmed that the application of MRET polymer to RF phones does not significantly affect the air measurements of RF phone signals, and subsequently does not lead to any significant distortion of transmitted RF signals.

[Parental education to reduce blood lead levels in children with mild and moderate lead poisoning: a randomized controlled study].

PubMed

Shen, Xiao-ming; Yan, Chong-huai; Wu, Sheng-hu; Shi, Rong

2004-12-01

To evaluate the effectiveness of parental education on reducing lead exposure of children by examining the changes in blood lead levels of children whose parents receiving or not receiving educational intervention. Two hundred children with confirmed blood lead levels beyond 100 microg/L were selected. They were randomized into two groups, 107 children in study group and 93 in control. At the beginning of the study, parents of both study and control groups were called for interview to complete KABP questionnaire and lead study questionnaire. The study group was provided with interventional measures while control group was not contacted until the end of study. Intervention of parental education was undertaken by means of a TV program, a set of slides and a brochure, and focused on the questions regarding harmful effects of lead poisoning, the sources of environmental lead and prevention of this preventable disease. Tests for blood lead level were repeated for both study and control groups 3 months after the determination of the initial blood lead level. All the relevant knowledge of health effect, lead sources and prevention of childhood lead poisoning of participating parents of study group were improved significantly (chi(2) = 14.06, 13.07, 10.08, 28.26, P < 0.01) after educational intervention while parents control group also were significantly improved in the sub-catalogs of concept and prevention (chi(2) = 7.69, 8.64, P < 0.01), but not the health effect and sources of childhood lead poisoning. Children and parents' behavior in study group was improved accordingly and significantly. Less children ate popcorn (chi(2) = 4.08, P < 0.05), less children drank tap-water in the morning (chi(2) = 23.04, P < 0.01), more kids washed their hands before eating (chi(2) = 5.82, P < 0.05), less kids played on road side (chi(2) = 9.60, P < 0.01), and more parents changed their coat or took shower or washed hands before going home after work (chi(2) = 4.00, P < 0.05). But in the control group only the number of kids playing on road side was decreased significantly (chi(2) = 9.60, P < 0.01). A general decline in blood lead levels was detected in both groups with statistical significance at P < 0.01. However, the decrease in blood lead levels was more remarkable in the study group. There was average reduction of 55 microg/L (35%) in blood lead levels for study group (t = 4.979, P < 0.01) and an almost 33 microg/L (20%) for control (t = 3.398, P < 0.01). The reduction in blood lead level was 22 microg/L greater in study group (t = 3.531, P < 0.01). The study also showed that the effectiveness of the educational interventions depended upon various aspects. Fourteen variables were included in the stepwise multiple regression equation of blood lead level changes. Such as parents' occupational exposure to lead, the improvement of knowledge about prevention of childhood lead poisoning, the chang of habit of snacks intake, parents' education levels, the change of attitude of parents for the childhood lead poisoning, etc. Educating parents is proved to be an effective approach for children with mild and moderate lead poisoning.

Lack of observed movement response to lead exposure of California condors

USGS Publications Warehouse

Poessel, Sharon; Brandt, Joseph; Uyeda, Linda; Astell, Molly; Katzner, Todd E.

2018-01-01

Lead poisoning is an important conservation concern for wildlife, and scavenging birds are especially at risk from consumption of carcasses of animals killed with lead ammunition. Because current methods to identify lead exposure require animal capture and blood collection, management would benefit from the development of a less costly and noninvasive behavioral test for illness in wild animals. We attempted to design such a test to identify lead exposure in California condors (Gymnogyps californianus) that we tracked with global positioning system (GPS) telemetry in southern California, USA, 2013–2016. We measured blood-lead concentrations in tracked birds and expected that flight behavior would be influenced by lead exposure; thus, we measured the effect of blood-lead concentrations on 2 different types of movement rates and on the proportion of time condors spent in flight. We found no effect of lead exposure on any of these 3 behavioral metrics. Our work suggests that the measurements we took of flight behaviors were not a useful tool in predicting lead exposure in the mildly to moderately exposed birds we studied. Wild birds are effective at hiding illness, especially condors who have a strong social hierarchy in which showing weakness is a disadvantage. However, focusing on behaviors other than flight, expanding the sample studied to include birds with a wider range of lead concentration values, or analyzing tissues such as feathers (rather than, or in addition to, blood) may be more useful for identification of lead exposure and other diseases that may limit wildlife populations. © 2017 This article is a U.S. Government work and is in the public domain in the USA.

Malondialdehyde-Deoxyguanosine Adduct Formation in Workers of Pathology Wards. The Role of Air Formaldehyde Exposure

PubMed Central

Romanazzi, Valeria; Munnia, Armelle; Piro, Sara; Allione, Alessandra; Ricceri, Fulvio; Guarrera, Simonetta; Pignata, Cristina; Matullo, Giuseppe; Wang, Poguang; Giese, Roger W.; Peluso, Marco

2010-01-01

Background Formaldehyde is a ubiquitous pollutant to which humans are exposed. Pathologists can experience high formaldehyde exposure levels. Formaldehyde – among other properties – induce oxidative stress and free radicals, which react with DNA and lipids, leading to oxidative damage and lipid peroxidation, respectively. We measured the levels of air-formaldehyde exposure in a group of Italian pathologists and controls. We analyzed the effect of formaldehyde exposure on leukocyte malondialdehyde-deoxyguanosine adducts (M1-dG), a biomarker of oxidative stress and lipid peroxidation. We studied the relationship between air-formaldehyde and M1-dG adducts. Methods Air-formaldehyde levels were measured by personal air samplers. M1-dG adducts were analyzed by 32P-postlabelling assay. Results Reduction rooms pathologists were significantly exposed to air-formaldehyde in respect to controls and to the pathologists working in other laboratory areas (p<0.001). A significant difference for M1-dG adducts between exposed pathologists and controls was found (p=0.045). The effect becomes stronger when the evaluation of air-formaldehyde exposure was based on personal samplers (p=0.018). Increased M1dG adduct levels were only found in individuals exposed to air-formaldehyde concentrations higher than 66 μg/m3. When the exposed workers and controls were subgrouped according to smoking, M1-dG tended to increase in all the subjects but a significant association between M1-dG and air-formaldehyde was only found in not smokers (p= 0.009). Air formaldehyde played a role positive but not significant (r = 0.355, p = 0.075, Pearson correlation) in the formation of M1-dG, only in not smokers. Conclusions Working in the reduction rooms and to be exposed to air-formaldehyde concentrations higher than 66 μg/m3 is associated with increased levels of M1-dG adducts. PMID:20707408

Lead Poisoning Prevention Tips

MedlinePlus

... be done to prevent exposure to lead? Lead-Safe Work Coloring book Reduce a child’s exposure from non- ... here to print a coloring storybook on lead-safe work [PDF - 1.94 MB] . Top of Page To ...

Household interventions for preventing domestic lead exposure in children.

PubMed

Nussbaumer-Streit, Barbara; Yeoh, Berlinda; Griebler, Ursula; Pfadenhauer, Lisa M; Busert, Laura K; Lhachimi, Stefan K; Lohner, Szimonetta; Gartlehner, Gerald

2016-10-16

Lead poisoning is associated with physical, cognitive and neurobehavioural impairment in children, and trials have tested many household interventions to prevent lead exposure. This is an update of the original review, first published in 2008. To assess the effects of household interventions for preventing or reducing lead exposure in children, as measured by improvements in cognitive and neurobehavioural development, reductions in blood lead levels and reductions in household dust lead levels. In May 2016 we searched CENTRAL, Ovid MEDLINE, Embase, nine other databases and two trials registers: the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) and ClinicalTrials.gov. We also checked the reference lists of relevant studies and contacted experts to find unpublished studies. Randomised controlled trials (RCTs) and quasi-RCTs of household educational or environmental interventions, or combinations of interventions to prevent lead exposure in children (from birth to 18 years of age), where investigators reported at least one standardised outcome measure. Two authors independently reviewed all eligible studies for inclusion, assessed risk of bias and extracted data. We contacted trialists to obtain missing information. We assessed the quality of the evidence using the GRADE approach. We included 14 studies involving 2643 children: 13 RCTs (involving 2565 children) and one quasi-RCT (involving 78 children). Children in all studies were under six years of age. Thirteen studies took place in urban areas of North America, and one was in Australia. Most studies were in areas with low socioeconomic status. Girls and boys were equally represented in all studies. The duration of the intervention ranged from 3 months to 24 months in 12 studies, while 2 studies performed interventions on a single occasion. Follow-up periods ranged from 6 months to 48 months. Three RCTs were at low risk of bias in all assessed domains. We rated two RCTs and one quasi-RCT as being at high risk of selection bias and six RCTs as being at high risk of attrition bias. For educational interventions, we rated the quality of evidence to be high for continuous blood lead levels and moderate for all other outcomes. For environmental interventions, we assessed the quality of evidence as moderate to low. National or international research grants or governments funded 12 studies, while the other 2 did not report their funding sources.No studies reported on cognitive or neurobehavioural outcomes. No studies reported on adverse events in children. All studies reported blood lead level outcomes.We put studies into subgroups according to their intervention type. We performed meta-analyses of both continuous and dichotomous data for subgroups where appropriate. Educational interventions were not effective in reducing blood lead levels (continuous: mean difference (MD) 0.02, 95% confidence interval (CI) -0.09 to 0.12, I² = 0%; 5 studies; N = 815; high quality evidence (log transformed); dichotomous ≥ 10.0 µg/dL (≥ 0.48 µmol/L): risk ratio (RR) 1.02, 95% CI 0.79 to 1.30; I² = 0%; 4 studies; N = 520; moderate quality evidence; dichotomous ≥ 15.0 µg/dL (≥ 0.72 µmol/L): RR 0.60, 95% CI 0.33 to 1.09; I² = 0%; 4 studies; N = 520; moderate quality evidence). Meta-analysis for the dust control subgroup also found no evidence of effectiveness on blood lead levels (continuous: MD -0.15, 95% CI -0.42 to 0.11; I² = 90%; 3 studies; N = 298; low quality evidence (log transformed); dichotomous ≥ 10.0 µg/dL (≥ 0.48 µmol/L): RR 0.93, 95% CI 0.73 to 1.18; I² = 0; 2 studies; N = 210; moderate quality evidence; dichotomous ≥ 15.0 µg/dL (≥ 0.72 µmol/L): RR 0.86, 95% CI 0.35 to 2.07; I² = 56%; 2 studies; N = 210; low quality evidence). After adjusting the dust control subgroup for clustering in meta-analysis, we found no evidence of effectiveness. We could not pool the studies using soil abatement (removal and replacement) and combination intervention groups in a meta-analysis due to substantial differences between studies, and generalisability or reproducibility of the results from these studies is unknown. Therefore, there is currently insufficient evidence to clarify whether soil abatement or a combination of interventions reduces blood lead levels. Based on current knowledge, household educational interventions are ineffective in reducing blood lead levels in children as a population health measure. Dust control interventions may lead to little or no difference in blood lead levels (the quality of evidence was moderate to low, meaning that future research is likely to change these results). There is currently insufficient evidence to draw conclusions about the effectiveness of soil abatement or combination interventions. No study reported on cognitive or neurobehavioural outcomes or adverse events. These patient-relevant outcomes would have been of great interest to draw conclusions for practice.Further trials are required to establish the most effective intervention for preventing lead exposure. Key elements of these trials should include strategies to reduce multiple sources of lead exposure simultaneously using empirical dust clearance levels. It is also necessary for trials to be carried out in low- and middle-income countries and in differing socioeconomic groups in high-income countries.

Economic Costs of Childhood Lead Exposure in Low- and Middle-Income Countries

PubMed Central

Trasande, Leonardo

2013-01-01

Background: Children’s blood lead levels have declined worldwide, especially after the removal of lead in gasoline. However, significant exposure remains, particularly in low- and middle-income countries. To date, there have been no global estimates of the costs related to lead exposure in children in developing countries. Objective: Our main aim was to estimate the economic costs attributable to childhood lead exposure in low- and middle-income countries. Methods: We developed a regression model to estimate mean blood lead levels in our population of interest, represented by each 1-year cohort of children < 5 years of age. We used an environmentally attributable fraction model to estimate lead-attributable economic costs and limited our analysis to the neurodevelopmental impacts of lead, assessed as decrements in IQ points. Our main outcome was lost lifetime economic productivity due to early childhood exposure. Results: We estimated a total cost of $977 billions of international dollars in low- and middle-income countries, with economic losses equal to $134.7 billion in Africa [4.03% of gross domestic product (GDP)], $142.3 billion in Latin America and the Caribbean (2.04% of GDP), and $699.9 billion in Asia (1.88% of GDP). Our sensitivity analysis indicates a total economic loss in the range of $728.6–1162.5 billion. Conclusions: We estimated that, in low- and middle-income countries, the burden associated with childhood lead exposure amounts to 1.20% of world GDP in 2011. For comparison, in the United States and Europe lead-attributable economic costs have been estimated at $50.9 and $55 billion, respectively, suggesting that the largest burden of lead exposure is now borne by low- and middle-income countries. Citation: Attina TM, Trasande L. 2013. Economic costs of childhood lead exposure in low- and middle-income countries. Environ Health Perspect 121:1097–1102; http://dx.doi.org/10.1289/ehp.1206424 PMID:23797342

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

PubMed

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

2015-01-01

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

Reducing Environmental Allergic Triggers: Policy Issues.

PubMed

Abramson, Stuart L

The implementation of policies to reduce environmental allergic triggers can be an important adjunct to optimal patient care for allergic rhinitis and allergic asthma. Policies at the local level in schools and other public as well as private buildings can make an impact on disease morbidity. Occupational exposures for allergens have not yet been met with the same rigorous policy standards applied for exposures to toxicants by Occupational Safety and Health Administration. Further benefit may be obtained through policies by local, county, state, and national governments, and possibly through international cooperative agreements. The reduction of allergenic exposures can and should be affected by policies with strong scientific, evidence-based derivation. However, a judicious application of the precautionary principle may be needed in circumstances where the health effect of inaction could lead to more serious threats to vulnerable populations with allergic disease. This commentary covers the scientific basis, current implementation, knowledge gaps, and pro/con views on policy issues in reducing environmental allergic triggers. Copyright © 2017 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Paternal exposure to cigarette smoke condensate leads to reproductive sequelae and developmental abnormalities in the offspring of mice.

PubMed

Esakky, Prabagaran; Hansen, Deborah A; Drury, Andrea M; Felder, Paul; Cusumano, Andrew; Moley, Kelle H

2016-10-01

Paternal smoking is associated with infertility, birth defects and childhood cancers. Our earlier studies using cigarette smoke condensate (CSC) demonstrated several deleterious changes in male germ cells. Here, we hypothesize that chronic paternal exposure to CSC causes molecular and phenotypic changes in the sire and the offspring, respectively. In this mouse study, CSC caused DNA damage and cytotoxicity in testes via accumulation of benzo(a)pyrene (B[a]P) and cotinine. Decreased expression of growth arrest and DNA damage inducible alpha (Gadd45a), aryl hydrocarbon receptor (Ahr), and cyclin-dependent kinase inhibitor 1A (P21) was seen in CSC exposed testes. Apoptotic germ cell death was detected by induction of Fas, FasL, and activated caspase-3. The CSC-exposed males displayed reduction in sperm motility and fertilizing ability and sired pups with reduced body weight and crown-rump length, and smaller litter size with higher numbers of resorption. This model of CSC exposure demonstrates testicular toxicity and developmental defects in the offspring. Copyright © 2016 Elsevier Inc. All rights reserved.

Evaluation of effect of high frequency electromagnetic field on growth and antibiotic sensitivity of bacteria.

PubMed

Salmen, Saleh H; Alharbi, Sulaiman A; Faden, Asmaa A; Wainwright, M

2018-01-01

This study was aimed to evaluate the impact of high frequency electromagnetic fields (HF-EMF at 900 and 1800 MHz) on DNA, growth rate and antibiotic susceptibility of S. aureus , S. epidermidis , and P. aeruginosa . In this study, bacteria were exposed to 900 and 1800 MHz for 2 h and then inoculated to new medium when their growth rate and antibiotic susceptibility were evaluated. Results for the study of bacterial DNA unsuccessful to appearance any difference exposed and non-exposed S. aureus and S. epidermidis . Exposure of S. epidermidis and S. aureus to electromagnetic fields mostly produced no statistically significant decrease in bacterial growth, except for S. aureus when exposure to 900 MHz at 12 h. Exposure of P. aeruginosa to electromagnetic fields at 900 MHz however, lead to a significant reduction in growth rate, while 1800 MHz had insignificant effect. With the exception of S. aureus , treated with amoxicillin (30 µg) and exposed to electromagnetic fields, radiation treatment had no significant effect on bacterial sensitivity to antibiotics.

Quercitrin Protects Skin from UVB-induced Oxidative Damage

PubMed Central

Yin, Yuanqin; Li, Wenqi; Son, Yong-Ok; Sun, Lijuan; Lu, Jian; Kim, Donghern; Wang, Xin; Yao, Hua; Wang, Lei; Pratheeshkumar, Poyil; Hitron, Andrew J; Luo, Jia; Gao, Ning; Shi, Xianglin; Zhang, Zhuo

2013-01-01

Exposure of the skin to ultraviolet B (UVB) radiation causes oxidative damage to skin, resulting in sunburn, photoaging, and skin cancer. It is generally believed that the skin damage induced by UV irradiation is a consequence of generation of reactive oxygen species (ROS). Recently, there is an increased interest in the use of natural products as chemopreventive agents for non-melanoma skin cancer (NMSC) due to their antioxidants and anti-inflammatory properties. Quercitrin, glycosylated form of quercetin, is the most common flavonoid in nature with antioxidant properties. The present study investigated the possible beneficial effects of quercitrin to inhibit UVB irradiation-induced oxidative damage in vitro and in vivo. Our results showed that quercitrin decreased ROS generation induced by UVB irradiation in JB6 cells. Quercitrin restored catalase expression and GSH/GSSG ratio reduced by UVB exposure, two major antioxidant enzymes, leading to reductions of oxidative DNA damage and apoptosis and protection of the skin from inflammation caused by UVB exposure. The present study demonstrated that quercitrin functions as an antioxidant against UVB irradiation-induced oxidative damage to skin. PMID:23545178

Quercitrin protects skin from UVB-induced oxidative damage.

PubMed

Yin, Yuanqin; Li, Wenqi; Son, Young-Ok; Sun, Lijuan; Lu, Jian; Kim, Donghern; Wang, Xin; Yao, Hua; Wang, Lei; Pratheeshkumar, Poyil; Hitron, Andrew J; Luo, Jia; Gao, Ning; Shi, Xianglin; Zhang, Zhuo

2013-06-01

Exposure of the skin to ultraviolet B (UVB) radiation causes oxidative damage to skin, resulting in sunburn, photoaging, and skin cancer. It is generally believed that the skin damage induced by UV irradiation is a consequence of generation of reactive oxygen species (ROS). Recently, there is an increased interest in the use of natural products as chemopreventive agents for non-melanoma skin cancer (NMSC) due to their antioxidants and anti-inflammatory properties. Quercitrin, glycosylated form of quercetin, is the most common flavonoid in nature with antioxidant properties. The present study investigated the possible beneficial effects of quercitrin to inhibit UVB irradiation-induced oxidative damage in vitro and in vivo. Our results showed that quercitrin decreased ROS generation induced by UVB irradiation in JB6 cells. Quercitrin restored catalase expression and GSH/GSSG ratio reduced by UVB exposure, two major antioxidant enzymes, leading to reductions of oxidative DNA damage and apoptosis and protection of the skin from inflammation caused by UVB exposure. The present study demonstrated that quercitrin functions as an antioxidant against UVB irradiation-induced oxidative damage to skin. Copyright © 2013 Elsevier Inc. All rights reserved.

Intra‐Target Microdosing – A Novel Drug Development Approach: Proof of Concept, Safety, and Feasibility Study in Humans

PubMed Central

MacLeod, D; Lee, K; Santoro, A; DeMasi, DK; Hawk, T; Feinglos, M; Rowland, M; Noveck, RJ

2017-01-01

Abstract Intra‐Target Microdosing (ITM) is a novel drug development approach aimed at increasing the efficiency of first‐in‐human (FIH) testing of new molecular entities (NMEs). ITM combines intra‐target drug delivery and “microdosing,” the subpharmacological systemic exposure. We hypothesized that when the target tissue is small (about 1/100th of total body mass), ITM can lead to target therapeutic‐level exposure with minimal (microdose) systemic exposure. Each of five healthy male volunteers received insulin microdose into the radial artery or full therapeutic dose intravenously in separate visits. Insulin and glucose levels were similar between systemic administration and ITM administration in the ipsilateral hand, and glucose levels demonstrated a reduction in the ipsilateral hand but not in the contralateral hand. Positron emission tomography (PET) imaging of 18F‐fluorodeoxyglucose (FDG) uptake demonstrated differences between the ipsilateral and contralateral arms. The procedures were safe and well‐tolerated. Results are consistent with ITM proof‐of‐concept (POC) and demonstrate the ethical, regulatory, and logistical feasibility of the approach. PMID:28689370

Effectiveness of an occupational health intervention program to reduce whole body vibration exposure: an evaluation study with a controlled pretest-post-test design.

PubMed

Tiemessen, Ivo J H; Hulshof, Carel T J; Frings-Dresen, Monique H W

2009-12-01

An effective intervention program aiming to reduce whole body vibration (WBV) exposure at work will reduce the number of low back complaints in the near future. An evaluation study with a controlled pretest-post-test design. Nine companies and 126 drivers were included in the study. Cluster randomization on company level divided the drivers and their employers in an intervention group and a "care-as-usual" group. At baseline (T0) and intervention program was implemented and evaluated after 7 months (T1). The main outcome measure was WBV exposure. Process measures included knowledge, attitude, and (intended) behavior towards reduction of WBV exposure for the drivers and knowledge and WBV policy for the employers. At T1, no significant reduction was found in WBV exposure within both groups compared with T0. Probably due to poor to moderate compliance, the intervention program was not effective in reducing the WBV exposure on group level but small reductions in WBV exposure are possible when intervention compliance is high. Copyright 2009 Wiley-Liss, Inc.

[Prenatal lead exposure related to cord blood brain derived neurotrophic factor (BDNF) levels and impaired neonatal neurobehavioral development].

PubMed

Ren, L H; Mu, X Y; Chen, H Y; Yang, H L; Qi, W

2016-06-01

To explore the relationship between umbilical cord blood brain-derived neurotrophic factor (BDNF) and neonatal neurobehavioral development in lead exposure infants. All infants and their mother were randomly selected during 2011 to 2012, subjects were selected according to the umbilical cord blood lead concentrations, which contcentration of lead was higher than 0.48 μmol/L were taken into high lead exposure group, about 60 subjects included. Comparing to the high lead exposure group, according to gender, weight, pregnant week, length and head circumferenece, the level of cord blood lead concentration under 0.48 μmol/L were taken into control group, 60 cases included. Lead content was determined by graphite furnace atomic absorption spectrometry. Neonatal behavioral neurological assessment (NBNA) was used to determine the development of neonatal neuronal behavior. The content of BDNF was detected by ELISA. Comparing the BDNF and the NBNA score between two groups, and linear correlation was given on analysis the correlation between lead concentration in cord blood and BDNF, BDNF and the NBNA score. Lead content in high exposure group was (0.613±0.139) μmol/L, and higher than (0.336±0.142) μmol/L in low exposure group (t=3.21, P<0.001) . NBNA summary score (36.35±1.86), active muscle tension score (6.90±0.27) and general assessment score (5.93±0.32) in high exposure group were lower than those (38.13±0.96, 7.79±0.35, 6.00±0.00) in low exposure group (t values were 8.21, 10.23, 2.32, respectively, P values were <0.001, <0.001 and 0.037) . BDNF content in high exposure group which was (3.538±1.203) ng/ml was higher than low exposure group (2.464±0.918) ng/ml (t=7.60, P<0.001). The correlation analysis found that the cord blood BDNF content was negatively correlated with NBNA summary score, passive muscle tension and active muscle tone score (r was -0.27, -0.29, -0.30, respectively, P values were <0.001, respectively) . Prenatal lead exposure results poor neonatal neurobehavioral development and cord blood BDNF was negatively correlated with neonatal neurodevelopment, may serve as a useful biomarker.

Combining group-based exposure therapy with prolonged exposure to treat U.S. Vietnam veterans with PTSD: a case study.

PubMed

Ready, David J; Vega, Edward M; Worley, Virginia; Bradley, Bekh

2012-10-01

Group-based exposure therapy (GBET) of 16-week duration was developed to treat combat-related posttraumatic stress disorder (PTSD) and decreased PTSD symptoms in 3 noncontrolled open trials with low attrition (0%-5%). Group-based exposure therapy has not produced as much PTSD symptom reduction as Prolonged Exposure (PE) within a U.S. Veterans Affairs PTSD treatment program, although PE had more dropouts (20%). This pilot study was of a model that combined key elements of GBET with components of PE in an effort to increase the effectiveness of a group-based treatment while reducing its length and maintaining low attrition. Twice per week, 8 Vietnam combat veterans with PTSD were treated for 12 weeks, with an intervention that included 2 within-group war trauma presentations per participant, 6 PE style individual imaginal exposure (IE) sessions per participant, daily listening to recorded IE sessions, and daily in vivo exposure exercises. All completed treatment and showed Significant reductions on all measures of PTSD with large effect sizes; 7 participants no longer met PTSD criteria on treating clinician administered interviews and a self-report measure at posttreatment. Significant reductions in depression with large effect sizes and moderate reductions in PTSD-related cognitions were also found. Most gains were maintained 6 months posttreatment. Published 2012. This article is a US Government work and is in the public domain in the USA.

Dietary acrylamide exposure among Finnish adults and children: the potential effect of reduction measures.

PubMed

Hirvonen, T; Jestoi, M; Tapanainen, H; Valsta, L; Virtanen, S M; Sinkko, H; Kronberg-Kippilä, C; Kontto, J; Virtamo, J; Simell, O; Peltonen, K

2011-11-01

A deterministic exposure assessment using the Nusser method that adjusts for within-subject variation and for nuisance effects among Finnish children and adults was carried out. The food consumption data covered 2038 adults (25-74 years old) and 1514 children of 1, 3 and 6 years of age, with the data on foods' acrylamide content obtained from published Finnish studies. We found that acrylamide exposure was highest among the 3-year-old children (median = 1.01 µg kg(-1) bw day(-1), 97.5th percentile = 1.95 µg kg(-1) bw day(-1)) and lowest among 65-74-year-old women (median = 0.31 µg kg(-1) bw day(-1), 97.5th percentile = 0.69 µg kg(-1) bw day(-1)). Among adults, the most important source of acrylamide exposure was coffee, followed by casseroles rich in starch, then rye bread. Among children, the most important sources were casseroles rich in starch and then biscuits and, finally, chips and other fried potatoes. Replacing lightly roasted coffee with dark-roasted, swapping sweet wheat buns for biscuits, and decreasing the acrylamide content of starch-based casseroles and rye bread by 50% would result in a 50% decrease in acrylamide exposure in adults. Among children, substituting boiled potatoes for chips and other friend potatoes and replacing biscuits with sweet wheat buns while lowering the acrylamide content of starch-based casseroles by 50% would lead to acrylamide exposure that is only half of the original exposure. In conclusions, dietary modifications could have a large impact in decreasing acrylamide exposure.

Tinnitus with a normal audiogram: Relation to noise exposure but no evidence for cochlear synaptopathy.

PubMed

Guest, Hannah; Munro, Kevin J; Prendergast, Garreth; Howe, Simon; Plack, Christopher J

2017-02-01

In rodents, exposure to high-level noise can destroy synapses between inner hair cells and auditory nerve fibers, without causing hair cell loss or permanent threshold elevation. Such "cochlear synaptopathy" is associated with amplitude reductions in wave I of the auditory brainstem response (ABR) at moderate-to-high sound levels. Similar ABR results have been reported in humans with tinnitus and normal audiometric thresholds, leading to the suggestion that tinnitus in these cases might be a consequence of synaptopathy. However, the ABR is an indirect measure of synaptopathy and it is unclear whether the results in humans reflect the same mechanisms demonstrated in rodents. Measures of noise exposure were not obtained in the human studies, and high frequency audiometric loss may have impacted ABR amplitudes. To clarify the role of cochlear synaptopathy in tinnitus with a normal audiogram, we recorded ABRs, envelope following responses (EFRs), and noise exposure histories in young adults with tinnitus and matched controls. Tinnitus was associated with significantly greater lifetime noise exposure, despite close matching for age, sex, and audiometric thresholds up to 14 kHz. However, tinnitus was not associated with reduced ABR wave I amplitude, nor with significant effects on EFR measures of synaptopathy. These electrophysiological measures were also uncorrelated with lifetime noise exposure, providing no evidence of noise-induced synaptopathy in this cohort, despite a wide range of exposures. In young adults with normal audiograms, tinnitus may be related not to cochlear synaptopathy but to other effects of noise exposure. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Aflatoxin exposure in utero causes growth faltering in Gambian infants.

PubMed

Turner, Paul C; Collinson, Andrew C; Cheung, Yin Bun; Gong, Yunyun; Hall, Andrew J; Prentice, Andrew M; Wild, Christopher P

2007-10-01

Growth faltering in West African children has previously been associated with dietary exposure to aflatoxins, particularly upon weaning. However, in animal studies in utero exposure to low levels of aflatoxin also results in growth faltering. This study investigated the effect of in utero aflatoxin exposure on infant growth in the first year of life in The Gambia. Height and weight were measured for 138 infants at birth and at regular monthly intervals for one year. Aflatoxin-albumin (AF-alb) adduct level was measured in maternal blood during pregnancy, in cord blood and in infants at age 16 weeks. The geometric mean AF-alb levels were 40.4 pg/mg (range 4.8-260.8 pg/mg), 10.1 pg/mg (range 5.0-189.6 pg/mg) and 8.7 pg/mg (range 5.0-30.2 pg/mg) in maternal, cord and infant blood, respectively. AF-alb in maternal blood was a strong predictor of both weight (P = 0.012) and height (P = 0.044) gain, with lower gain in those with higher exposure. A reduction of maternal AF-alb from 110 pg/mg to 10 pg/mg would lead to a 0.8 kg increase in weight and 2 cm increase in height within the first year of life. This study shows a strong effect of maternal aflatoxin exposure during pregnancy on growth in the first year of life and thus extends earlier observations of an association between aflatoxin exposure during infancy and growth faltering. The findings imply value in targeting intervention strategies at early life exposures.

Glutathione, glutathione-related enzymes, and oxidative stress in individuals with subacute occupational exposure to lead.

PubMed

Dobrakowski, Michał; Pawlas, Natalia; Hudziec, Edyta; Kozłowska, Agnieszka; Mikołajczyk, Agnieszka; Birkner, Ewa; Kasperczyk, Sławomir

2016-07-01

The aim of the study was to investigate the influence of subacute exposure to lead on the glutathione-related antioxidant defense and oxidative stress parameters in 36 males occupationally exposed to lead for 40±3.2days. Blood lead level in the examined population increased significantly by 359% due to lead exposure. Simultaneously, erythrocyte glutathione level decreased by 16%, whereas the activity of glutathione-6-phosphate dehydrogenase in erythrocytes and leukocytes decreased by 28% and 10%, respectively. Similarly, the activity of glutathione-S-transferase in erythrocytes decreased by 45%. However, the activity of glutathione reductase in erythrocytes and leukocytes increased by 26% and 6%, respectively, whereas the total oxidant status value in leukocytes increased by 37%. Subacute exposure to lead results in glutathione pool depletion and accumulation of lipid peroxidation products; however, it does not cause DNA damage. Besides, subacute exposure to lead modifies the activity of glutathione-related enzymes. Copyright © 2016 Elsevier B.V. All rights reserved.

Low level lead exposure: history and discovery.

PubMed

Needleman, Herbert

2009-04-01

The history of lead toxicity spans 2 millennnia. With increasingly sensitive methods, deficits due to lead exposure have been demonstrated at lower and lower doses. Persuasive evidence suggests that no threshold for lead toxicity exists.

Selenium protects reproductive system and foetus development in a rat model of gestational lead exposure.

PubMed

Shen, W; Chen, J; Yin, J; Wang, S-L

2016-01-01

Lead is a common environmental contaminant. Lead accumulation in the body is especially dangerous for pregnant women and newborns. Selenium is a trace element which may rectify the damaging effects of lead. Here we tested potential protective effects of selenium against gestational lead exposure. Pregnant SD rats were exposed to 200 mg/L of lead acetate (given with water), with or without sodium selenite supplementation (2-8 mg/kg/day via intragastric administration). Pregnant rats not exposed to lead or selenium served as control animals. The outcomes in pregnant rats were serum lead and selenium levels, reproductive hormone (follicle-stimulating hormone, luteinizing hormone, prolactin, oestradiol, progesterone) levels, and uterine and ovarian morphological changes. The outcomes in the offspring were sex differentiation, survival rates (day 21 after birth), weight (days 0-35 after birth), weight of reproductive organs, and puberty onset (foreskin separation or vaginal opening). Selenium supplementation dose-dependently decreased serum lead levels, rectified reproductive hormone levels, and attenuated reproductive morphological changes caused by lead exposure. Lead exposure did not affect sex differentiation, but significantly (p < 0.05 vs. control animals) decreased the offspring weight on days 0-28 and the weight of their reproductive organs. Furthermore, lead exposure delayed the onset of puberty. These pathological changes were dose-dependently rectified or attenuated by selenium supplementation. Gestational lead exposure causes damages to the reproductive system of pregnant rats, and negatively modulates growth and reproductive system development of the offspring. These adverse effects are rectified or attenuated by selenium supplementation.

Gestational lead exposure induces developmental abnormalities and up-regulates apoptosis of fetal cerebellar cells in rats.

PubMed

Mousa, Alyaa M; Al-Fadhli, Ameera S; Rao, Muddanna S; Kilarkaje, Narayana

2015-01-01

Lead (Pb), a known environmental toxicant, adversely affects almost all organ systems. In this study, we investigated the effects of maternal lead exposure on fetal rat cerebellum. Female Sprague-Dawley rats were given lead nitrate in drinking water (0, 0.5, and 1%) for two weeks before conception, and during pregnancy. Fetuses were collected by caesarian section on gestational day 21 and observed for developmental abnormalities. The fetal cerebellar sections from control and 1% lead group were stained with cresyl violet. Immunohistochemical expressions of p53, Bax, Bcl-2, and caspase 3 were quantified by AnalySIS image analyzer (Life Science, Germany). Lead exposure induced developmental abnormalities of eyes, ear, limbs, neck and ventral abdominal wall; however, these abnormalities were commonly seen in the 1% lead-treated group. In addition, lead also caused fetal mortality and reduced body growth in both dose groups and reduced brain weight in the 1% lead-treated group. The fetal cerebella from the 1% lead-treated group showed unorganized cerebellar cortical layers, and degenerative changes in granule and Purkinje cells such as the formation of clumps of Nissl granules. An increase in Bax and caspase 3, and a decrease in Bcl-2 (p < 0.05), but not in p53, showed apoptosis of the neurons. In conclusion, gestational lead exposure in rats induces fetal toxicity and developmental abnormalities. The lead exposure also impairs development of cerebellar layers, induces structural changes, and apoptosis in the fetal cerebellar cortex. These results suggest that lead exposure during gestation is extremely toxic to developing cerebellum in rats.

Lead exposure in Latin America and the Caribbean. Lead Research Group of the Pan-American Health Organization.

PubMed Central

Romieu, I; Lacasana, M; McConnell, R

1997-01-01

As a result of the rapid industrialization of Latin America and the Caribbean during the second half of this century, exposure to lead has become an increasingly important problem. To obtain an estimate of the magnitude of lead exposure in the region, we carried out a survey and a literature search on potential sources of lead exposure and on blood lead concentrations. Sixteen out of 18 Latin American and 2 out of 10 Caribbean countries responded to the survey. Lead in gasoline remains a major problem, although the lead content has decreased in many countries in the last few years. The impact of leaded fuel is more important in urban settings, given their high vehicular density. Seventy-five percent of the population of the region lives in urban areas, and children younger than 15 years of age, the most susceptible group, comprise 30% of the population. Other sources of lead exposure identified in the region included industrial emissions, battery recycling, paint and varnishes, and contaminated food and water. Lead is recognized as a priority problem by national authorities in 72% of the countries that responded to the survey, and in 50% of the countries some legislation exists to regulate the lead content in certain products. However, compliance is low. There is an urgent need for a broad-based coalition between policy makers, industry, workers, unions, health care providers, and the community to take actions to reduce environmental and occupational lead exposures in all the Latin American and Caribbean countries. Images Figure 1. Figure 2. PMID:9189704

Global approach to reducing lead exposure and poisoning.

PubMed

Meyer, Pamela A; Brown, Mary Jean; Falk, Henry

2008-01-01

Lead poisoning is an important environmental disease that can have life-long adverse health effects. Most susceptible are children, and most commonly exposed are those who are poor and live in developing countries. Studies of children's blood-lead levels (BLLs) are showing cognitive impairment at increasingly lower BLLs. Lead is dangerous at all levels in children. The sources of lead exposure vary among and within countries depending on past and current uses. Sources of lead may be from historic contamination, recycling old lead products, or from manufacturing new products. In all countries that have banned leaded gasoline, average population BLLs have declined rapidly. In many developing countries where leaded gasoline is no longer used, many children and workers are exposed to fugitive emissions and mining wastes. Unexpected lead threats, such as improper disposal of electronics and children's toys contaminated with lead, continue to emerge. The only medical treatment available is chelation, which can save lives of persons with very high BLLs. However, chelating drugs are not always available in developing countries and have limited value in reducing the sequelae of chronic low dose lead exposure. Therefore, the best approach is to prevent exposure to lead. Because a key strategy for preventing lead poisoning is to identify and control or eliminate lead sources, this article highlights several major sources of lead poisoning worldwide. In addition, we recommend three primary prevention strategies for lead poisoning: identify sources, eliminate or control sources, and monitor environmental exposures and hazards.

Maternal Smoke Exposure Impairs the Long-Term Fertility of Female Offspring in a Murine Model.

PubMed

Camlin, Nicole J; Sobinoff, Alexander P; Sutherland, Jessie M; Beckett, Emma L; Jarnicki, Andrew G; Vanders, Rebecca L; Hansbro, Philip M; McLaughlin, Eileen A; Holt, Janet E

2016-02-01

The theory of fetal origins of adult disease was first proposed in 1989, and in the decades since, a wide range of other diseases from obesity to asthma have been found to originate in early development. Because mammalian oocyte development begins in fetal life it has been suggested that environmental and lifestyle factors of the mother could directly impact the fertility of subsequent generations. Cigarette smoke is a known ovotoxicant in active smokers, yet disturbingly 13% of Australian and 12% of US women continue to smoke throughout pregnancy. The focus of our investigation was to characterize the adverse effects of smoking on ovary and oocyte quality in female offspring exposed in utero. Pregnant mice were nasally exposed to cigarette smoke for 12 wk throughout pregnancy/lactation, and ovary and oocyte quality of the F1 (maternal smoke exposed) generation was examined. Neonatal ovaries displayed abnormal somatic cell proliferation and increased apoptosis, leading to a reduction in follicle numbers. Further investigation found that altered somatic cell proliferation and reduced follicle number continued into adulthood; however, apoptosis did not. This reduction in follicles resulted in decreased oocyte numbers, with these oocytes found to have elevated levels of oxidative stress, altered metaphase II spindle, and reduced sperm-egg interaction. These ovarian and oocyte changes ultimately lead to subfertility, with maternal smoke-exposed animals having smaller litters and also taking longer to conceive. In conclusion, our results demonstrate that in utero and lactational exposure to cigarette smoke can have long-lasting effects on the fertility of the next generation of females. © 2016 by the Society for the Study of Reproduction, Inc.

Chemical Forms of Selenium in the Metal-Resistant Bacterium Ralstonia metallidurans CH34 Exposed to Selenite and Selenate

PubMed Central

Sarret, Géraldine; Avoscan, Laure; Carrière, Marie; Collins, Richard; Geoffroy, Nicolas; Carrot, Francine; Covès, Jacques; Gouget, Barbara

2005-01-01

Ralstonia metallidurans CH34, a soil bacterium resistant to a variety of metals, is known to reduce selenite to intracellular granules of elemental selenium (Se0). We have studied the kinetics of selenite (SeIV) and selenate (SeVI) accumulation and used X-ray absorption spectroscopy to identify the accumulated form of selenate, as well as possible chemical intermediates during the transformation of these two oxyanions. When introduced during the lag phase, the presence of selenite increased the duration of this phase, as previously observed. Selenite introduction was followed by a period of slow uptake, during which the bacteria contained Se0 and alkyl selenide in equivalent proportions. This suggests that two reactions with similar kinetics take place: an assimilatory pathway leading to alkyl selenide and a slow detoxification pathway leading to Se0. Subsequently, selenite uptake strongly increased (up to 340 mg Se per g of proteins) and Se0 was the predominant transformation product, suggesting an activation of selenite transport and reduction systems after several hours of contact. Exposure to selenate did not induce an increase in the lag phase duration, and the bacteria accumulated approximately 25-fold less Se than when exposed to selenite. SeIV was detected as a transient species in the first 12 h after selenate introduction, Se0 also occurred as a minor species, and the major accumulated form was alkyl selenide. Thus, in the present experimental conditions, selenate mostly follows an assimilatory pathway and the reduction pathway is not activated upon selenate exposure. These results show that R. metallidurans CH34 may be suitable for the remediation of selenite-, but not selenate-, contaminated environments. PMID:15870319

Food contamination as a pathway for lead exposure in children during the 2010-2013 lead poisoning epidemic in Zamfara, Nigeria.

PubMed

Tirima, Simba; Bartrem, Casey; von Lindern, Ian; von Braun, Margrit; Lind, Douglas; Anka, Shehu Mohamed; Abdullahi, Aishat

2018-05-01

In 2010, an estimated 400 to 500 children died of acute lead poisoning associated with artisanal gold mining in Zamfara, Nigeria. Processing of gold ores containing up to 10% lead within residential compounds put residents, especially children, at the highest risk. Principal routes of exposure were incidental ingestion and inhalation of contaminated soil and dusts. Several Nigerian and international health organizations collaborated to reduce lead exposures through environmental remediation and medical treatment. The contribution of contaminated food to total lead exposure was assessed during the environmental health response. Objectives of this investigation were to assess the influence of cultural/dietary habits on lead exposure pathways and estimate the contribution of contaminated food to children's blood lead levels (BLLs). A survey of village dietary practices and staple food lead content was conducted to determine dietary composition, caloric intakes, and lead intake. Potential blood lead increments were estimated using bio-kinetic modeling techniques. Most dietary lead exposure was associated with contamination of staple cereal grains and legumes during post-harvest processing and preparation in contaminated homes. Average post-harvest and processed cereal grain lead levels were 0.32mg/kg and 0.85mg/kg dry weight, respectively. Age-specific food lead intake ranged from 7 to 78μg/day. Lead ingestion and absorption were likely aggravated by the dusty environment, fasting between meals, and nutritional deficiencies. Contamination of staple cereal grains by highly bioavailable pulverized ores could account for as much as 11%-34% of children's BLLs during the epidemic, and were a continuing source after residential soil remediation until stored grain inventories were exhausted. Copyright © 2017. Published by Elsevier B.V.

Changes in serial blood lead levels during pregnancy.

PubMed Central

Rothenberg, S J; Karchmer, S; Schnaas, L; Perroni, E; Zea, F; Fernández Alba, J

1994-01-01

The first step in modeling lead kinetics during pregnancy includes a description of sequential maternal blood lead (PbB) during pregnancy and the factors controlling it. We analyzed PbB of 105 women living in the Valley of Mexico from week 12 to week 36 of pregnancy and again at parturition. We also used data from all women contributing blood at any stage of pregnancy to determine antecedents of PbB. Pregnancies were uneventful, and offspring were normal. Although geometric mean PbB level averaged around 7.0 micrograms/dl (0.34 mumol/l), with a range of 1.0-35.5 micrograms/dl throughout pregnancy, analysis of variance revealed a significant decrease in mean PbB from week 12 to week 20 (1.1 micrograms/dl) and various significant increases in mean PbB from week 20 to parturition (1.6 micrograms/dl). Regression analyses confirmed the positive linear PbB trend from 20 weeks to parturition and additional contributions of dietary calcium, reproductive history, lifetime residence of Mexico City, coffee drinking, and use of indigenous lead-glazed pottery. Although decreasing hematocrit has been suggested to explain first-half pregnancy PbB decrease, the time course of hematocrit decrease in the present study did not match the sequential changes in PbB. While hemodilution and organ growth in the first half of pregnancy may account for much of the PbB decrease seen between 12 and 20 weeks, the remaining hemodilution and accelerated organ growth of the last half of pregnancy do not predict the trend toward increasing maternal PbB concentration from 20 weeks to delivery. Mobilization of bone lead, increased gut absorption, and increased retention of lead may explain part of the upward PbB trend in the second half of pregnancy. Reduction of lifetime lead exposure may be required to decrease risk of fetal exposure. Images Figure 1. Figure 2. PMID:9644197

Prenatal exposure to lead in France: Cord-blood levels and associated factors: Results from the perinatal component of the French Longitudinal Study since Childhood (Elfe).

PubMed

Saoudi, Abdessattar; Dereumeaux, Clémentine; Goria, Sarah; Berat, Bénédicte; Brunel, Serge; Pecheux, Marie; de Crouy-Chanel, Perrine; Zeghnoun, Abdelkrim; Rambaud, Loïc; Wagner, Vérène; le Tertre, Alain; Fillol, Clémence; Vandentorren, Stéphanie; Guldner, Laurence

2018-04-01

As a result of the ban on lead in gasoline on 2nd January 2000, the French population's exposure to lead has decreased in recent years. However, because of the acknowledged harmful cognitive effects of lead even at low levels, lead exposure remains a major public health issue. In France, few biomonitoring data are available for exposure to lead in pregnant women and newborn. The purpose of the perinatal component of the French human biomonitoring (HBM) program was to describe levels of various biomarkers of exposure to several environmental pollutants, including lead, among mother-baby pairs. In this paper, we aimed to describe the distribution of cord blood lead levels (CBLL) in French mother-baby pairs, and to estimate the contribution of the main lead exposure risk factors to these levels. A total of 1968 mother-baby pairs selected from the participants of the perinatal component of the French HBM program were included in the study on lead. Lead levels were analyzed in cord blood collected at child delivery by inductively coupled plasma-mass spectrometry (ICP-MS). The data collected included biological sample, socio-demographic characteristics, environmental and occupational exposure, and information on dietary factors. CBLL were quantified for 99.5% of the sample. The CBLL geometric mean was 8.30 μg/l (95% CI [7.94-8.68]) with a 95th percentile of 24.3 μg/l (95% CI [20.7-27.1]). Factors significantly associated with CBLL were tap water consumption, alcohol consumption, shellfish consumption, vegetable consumption, bread consumption, smoking, and the mother being born in countries where lead is often used. This study provides the first reference value for CBLL in a random sample of mother-baby pairs not particularly exposed to high levels of lead (24.3 μg/l). A substantial decrease in CBLL over time was observed, which confirms the decrease of exposure to lead among the general population. CBLL observed in this French study were in the range of those found in recent surveys conducted in other countries. Copyright © 2018 Elsevier GmbH. All rights reserved.

Developmental lead exposure attenuates methamphetamine dose-effect self-administration performance and progressive ratio responding in the male rat.

PubMed

Rocha, Angelica; Valles, Rodrigo; Hart, Nigel; Bratton, Gerald R; Nation, Jack R

2008-06-01

Perinatal (gestation/lactation) lead exposure modifies the reinforcement efficacy of various psychoactive drugs (e.g., cocaine, opiates) across the phases of initial selection, use, and abuse [Nation J.R., Cardon A.L., Heard H.M., Valles R., Bratton G.R. Perinatal lead exposure and relapse to drug-seeking behavior in the rat: a cocaine reinstatement study. Psychopharmacol 2003;168: 236-243.; Nation J.R., Smith K.R., Bratton G.R. Early developmental lead exposure increases sensitivity to cocaine in a self-administration paradigm. Pharmacol Biochem Behave 2004; 77: 127-13; Rocha A., Valles R., Cardon A.L., Bratton G.R., Nation J.R. Enhanced acquisition of cocaine self-administration in rats developmentally exposed to lead. Neuropsychopharmacol 2005; 30: 2058-2064.]. However, changes in sensitivity to methamphetamine across the phases of drug abuse have not been examined in animals perinatally exposed to lead. Because the mainstream popularity of methamphetamine in the United States is increasing and lead exposure continues to be widespread, an examination of this drug and how it may be modified by perinatal exposure to lead is warranted. The studies reported here examined the effects of perinatal lead exposure on adult self-administration of intravenous (i.v.) methamphetamine across the maintenance phase of drug addiction. Experiment 1 examined dose-effect patterns in control and lead-exposed animals. Experiment 2 evaluated control and lead-exposed animals in a progressive ratio task. Female rats were administered a 16-mg lead or a control solution for 30 days prior to breeding with non-exposed males. Exposure continued through pregnancy and lactation and was discontinued at weaning (postnatal day [PND] 21). Animals born to control or lead-exposed dams received indwelling jugular catheters as adults (PND 70) and subsequently were randomly assigned to one of the two studies, using only one male rat per litter for each study. The data showed a general attenuation of the reinforcement efficacy of methamphetamine in animals perinatally exposed to lead, as compared to control animals.

Job Tasks as Determinants of Thoracic Aerosol Exposure in the Cement Production Industry.

PubMed

Notø, Hilde; Nordby, Karl-Christian; Skare, Øivind; Eduard, Wijnand

2017-12-15

The aims of this study were to identify important determinants and investigate the variance components of thoracic aerosol exposure for the workers in the production departments of European cement plants. Personal thoracic aerosol measurements and questionnaire information (Notø et al., 2015) were the basis for this study. Determinants categorized in three levels were selected to describe the exposure relationships separately for the job types production, cleaning, maintenance, foreman, administration, laboratory, and other jobs by linear mixed models. The influence of plant and job determinants on variance components were explored separately and also combined in full models (plant&job) against models with no determinants (null). The best mixed models (best) describing the exposure for each job type were selected by the lowest Akaike information criterion (AIC; Akaike, 1974) after running all possible combination of the determinants. Tasks that significantly increased the thoracic aerosol exposure above the mean level for production workers were: packing and shipping, raw meal, cement and filter cleaning, and de-clogging of the cyclones. For maintenance workers, time spent with welding and dismantling before repair work increased the exposure while time with electrical maintenance and oiling decreased the exposure. Administration work decreased the exposure among foremen. A subjective tidiness factor scored by the research team explained up to a 3-fold (cleaners) variation in thoracic aerosol levels. Within-worker (WW) variance contained a major part of the total variance (35-58%) for all job types. Job determinants had little influence on the WW variance (0-4% reduction), some influence on the between-plant (BP) variance (from 5% to 39% reduction for production, maintenance, and other jobs respectively but an 79% increase for foremen) and a substantial influence on the between-worker within-plant variance (30-96% for production, foremen, and other workers). Plant determinants had little influence on the WW variance (0-2% reduction), some influence on the between-worker variance (0-1% reduction and 8% increase), and considerable influence on the BP variance (36-58% reduction) compared to the null models. Some job tasks contribute to low levels of thoracic aerosol exposure and others to higher exposure among cement plant workers. Thus, job task may predict exposure in this industry. Dust control measures in the packing and shipping departments and in the areas of raw meal and cement handling could contribute substantially to reduce the exposure levels. Rotation between low and higher exposed tasks may contribute to equalize the exposure levels between high and low exposed workers as a temporary solution before more permanent dust reduction measures is implemented. A tidy plant may reduce the overall exposure for almost all workers no matter of job type. © The Author 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Effects of fine particulate matter and its constituents on low birth weight among full-term infants in California

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

Basu, Rupa, E-mail: Rupa.Basu@oehha.ca.gov; Harris, Maria; Sie, Lillian

Relationships between prenatal exposure to fine particles (PM{sub 2.5}) and birth weight have been observed previously. Few studies have investigated specific constituents of PM{sub 2.5}, which may identify sources and major contributors of risk. We examined the effects of trimester and full gestational prenatal exposures to PM{sub 2.5} mass and 23 PM{sub 2.5} constituents on birth weight among 646,296 term births in California between 2000 and 2006. We used linear and logistic regression models to assess associations between exposures and birth weight and risk of low birth weight (LBW; <2500 g), respectively. Models were adjusted for individual demographic characteristics, apparentmore » temperature, month and year of birth, region, and socioeconomic indicators. Higher full gestational exposures to PM{sub 2.5} mass and several PM{sub 2.5} constituents were significantly associated with reductions in term birth weight. The largest reductions in birth weight were associated with exposure to vanadium, sulfur, sulfate, iron, elemental carbon, titanium, manganese, bromine, ammonium, zinc, and copper. Several of these PM{sub 2.5} constituents were associated with increased risk of term LBW. Reductions in birth weight were generally larger among younger mothers and varied by race/ethnicity. Exposure to specific constituents of PM{sub 2.5}, especially traffic-related particles, sulfur constituents, and metals, were associated with decreased birth weight in California. -- Highlights: • Examine full gestational and trimester fine particle and its constituents on term birth weight. • Fine particles and several of its constituents associated with birth weight reductions. • Largest reductions for traffic-related particles, sulfur constituents, and metals. • Greater birth weight reductions for younger mothers, and varied by race/ethnicity.« less

Economic costs of childhood lead exposure in low- and middle-income countries.

PubMed

Attina, Teresa M; Trasande, Leonardo

2013-09-01

Children's blood lead levels have declined worldwide, especially after the removal of lead in gasoline. However, significant exposure remains, particularly in low- and middle-income countries. To date, there have been no global estimates of the costs related to lead exposure in children in developing countries. Our main aim was to estimate the economic costs attributable to childhood lead exposure in low- and middle-income countries. We developed a regression model to estimate mean blood lead levels in our population of interest, represented by each 1-year cohort of children < 5 years of age. We used an environmentally attributable fraction model to estimate lead-attributable economic costs and limited our analysis to the neurodevelopmental impacts of lead, assessed as decrements in IQ points. Our main outcome was lost lifetime economic productivity due to early childhood exposure. We estimated a total cost of $977 billions of international dollars in low- and middle-income countries, with economic losses equal to $134.7 billion in Africa [4.03% of gross domestic product (GDP)], $142.3 billion in Latin America and the Caribbean (2.04% of GDP), and $699.9 billion in Asia (1.88% of GDP). Our sensitivity analysis indicates a total economic loss in the range of $728.6-1162.5 billion. We estimated that, in low- and middle-income countries, the burden associated with childhood lead exposure amounts to 1.20% of world GDP in 2011. For comparison, in the United States and Europe lead-attributable economic costs have been estimated at $50.9 and $55 billion, respectively, suggesting that the largest burden of lead exposure is now borne by low- and middle-income countries.

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

PubMed

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

2015-04-01

As a highly toxic heavy metal, the pollution and exposure risks of lead are of widespread concern for human health. However, the collection of blood samples for use as an indicator of lead pollution is not always feasible in most cohort or longitudinal studies, especially those involving children health. To evaluate the potential use of urinary lead as an indicator of exposure levels and source apportionment, accompanying with environmental media samples, lead concentrations and isotopic measurements (expressed as (207)Pb/(206)Pb, (208)Pb/(206)Pb and (204)Pb/(206)Pb) were investigated and compared between blood and urine from children living in the vicinities of a typical coking plant and lead-acid battery factory. The results showed urinary lead might not be a preferable proxy for estimating blood lead levels. Fortunately, urinary lead isotopic measurements could be used as an alternative for identifying the sources of children's lead exposure, which coincided well with the blood lead isotope ratio analysis. Copyright © 2015 Elsevier Ltd. All rights reserved.

Children's Lead Exposure: A Multimedia Modeling Analysis to Guide Public Health Decision-Making.

PubMed

Zartarian, Valerie; Xue, Jianping; Tornero-Velez, Rogelio; Brown, James

2017-09-12

Drinking water and other sources for lead are the subject of public health concerns around the Flint, Michigan, drinking water and East Chicago, Indiana, lead in soil crises. In 2015, the U.S. Environmental Protection Agency (EPA)'s National Drinking Water Advisory Council (NDWAC) recommended establishment of a "health-based, household action level" for lead in drinking water based on children's exposure. The primary objective was to develop a coupled exposure-dose modeling approach that can be used to determine what drinking water lead concentrations keep children's blood lead levels (BLLs) below specified values, considering exposures from water, soil, dust, food, and air. Related objectives were to evaluate the coupled model estimates using real-world blood lead data, to quantify relative contributions by the various media, and to identify key model inputs. A modeling approach using the EPA's Stochastic Human Exposure and Dose Simulation (SHEDS)-Multimedia and Integrated Exposure Uptake and Biokinetic (IEUBK) models was developed using available data. This analysis for the U.S. population of young children probabilistically simulated multimedia exposures and estimated relative contributions of media to BLLs across all population percentiles for several age groups. Modeled BLLs compared well with nationally representative BLLs (0-23% relative error). Analyses revealed relative importance of soil and dust ingestion exposure pathways and associated Pb intake rates; water ingestion was also a main pathway, especially for infants. This methodology advances scientific understanding of the relationship between lead concentrations in drinking water and BLLs in children. It can guide national health-based benchmarks for lead and related community public health decisions. https://doi.org/10.1289/EHP1605.

Prenatal lead exposure modifies the impact of maternal self-esteem on children's inattention behavior

PubMed Central

Xu, Jian; Hu, Howard; Wright, Rosalind; Sánchez, Brisa N.; Schnaas, Lourdes; Bellinger, David C.; Park, Sung Kyun; Martínez, Sandra; Hernández-Avila, Mauricio; Téllez-Rojo, Martha Maria; Wright, Robert O.

2015-01-01

Objective To prospectively evaluate the association of maternal self-esteem measured when their offspring were toddlers with the subsequent development of attention-deficit-hyperactivity-disorder (ADHD)-like behavior in their school-age offspring and the potential modifying effects of prenatal lead exposure. Study design We evaluated a subsample of 192 mother-child pairs from a long-running birth-cohort project that enrolled mothers in Mexico from 1994 to 2011. Prenatal lead exposure was assessed using cord blood lead and maternal bone lead around delivery (tibia and patella lead, measured by K-x-ray-fluorescence). When children were 2 years old, maternal self-esteem was measured using the Coopersmith-Self-esteem-Inventory. When children were 7-to-15 years old, children's blood lead levels and ADHD symptoms were assessed, and Conners’ Parental-Rating-Scales-Revised (CPRS-R) and Behavior-Rating-Inventory-of-Executive-Function-Parent Form (BRIEF-P) were used as measures of ADHD-like behavior. Results Adjusting for family economic status, marital status, maternal education and age, child's age and sex, and children's current blood lead levels, increased maternal self-esteem was associated with reduced child inattention behavior. Compared with those among high prenatal lead exposure (P25-P100), this association was stronger among low prenatal lead exposure groups (P1-P25, p-values for the interaction effects between prenatal lead exposure and maternal self-esteem levels < 0.10). Each 1-point increase in maternal self-esteem scores was associated with 0.6-to-1.3-point decrease in CPRS-R and BRIEF-P T-scores among groups with low cord blood lead and patella lead (P1-P25). Conclusions Children experiencing high maternal self-esteem during toddlerhood were less likely to develop inattention behavior at school-age. Prenatal lead exposure may play a role in attenuating this protective effect. PMID:26047683

Prenatal Lead Exposure Modifies the Impact of Maternal Self-Esteem on Children's Inattention Behavior.

PubMed

Xu, Jian; Hu, Howard; Wright, Rosalind; Sánchez, Brisa N; Schnaas, Lourdes; Bellinger, David C; Park, Sung Kyun; Martínez, Sandra; Hernández-Avila, Mauricio; Téllez-Rojo, Martha Maria; Wright, Robert O

2015-08-01

To prospectively evaluate the association of maternal self-esteem measured when their offspring were toddlers with the subsequent development of attention deficit hyperactivity disorder (ADHD)-like behavior in their school-age offspring and the potential modifying effects of prenatal lead exposure. We evaluated a subsample of 192 mother-child pairs from a long-running birth-cohort project that enrolled mothers in Mexico from 1994-2011. Prenatal lead exposure was assessed using cord blood lead and maternal bone lead around delivery (tibia and patella lead, measured by K-x-ray-fluorescence). When children were 2 years old, maternal self-esteem was measured using the Coopersmith Self-Esteem Inventory. When children were 7-15 years old, children's blood lead levels and ADHD symptoms were assessed, and Conners' Parent Rating Scale-Revised and Behavior Rating Inventory of Executive Function-Parent Form were used as measures of ADHD-like behavior. Adjusting for family economic status, marital status, maternal education and age, child's age and sex, and children's current blood lead levels, increased maternal self-esteem was associated with reduced child inattention behavior. Compared with those among high prenatal lead exposure (P25-P100), this association was stronger among low prenatal lead exposure groups (P1-P25, P values for the interaction effects between prenatal lead exposure and maternal self-esteem levels of <.10). Each 1-point increase in maternal self-esteem scores was associated with 0.6- to 1.3-point decrease in Conners' Parent Rating Scale-Revised and Behavior Rating Inventory of Executive Function-Parent Form T-scores among groups with low cord blood lead and patella lead (P1-P25). Children experiencing high maternal self-esteem during toddlerhood were less likely to develop inattention behavior at school age. Prenatal lead exposure may play a role in attenuating this protective effect. Copyright © 2015 Elsevier Inc. All rights reserved.

Bar workers' exposure to second-hand smoke: the effect of Scottish smoke-free legislation on occupational exposure.

PubMed

Semple, Sean; Maccalman, Laura; Naji, Audrey Atherton; Dempsey, Scott; Hilton, Shona; Miller, Brian G; Ayres, Jon G

2007-10-01

To examine changes in bar workers' exposure to second-hand smoke (SHS) over a 12-month period before and after the introduction of Scottish smoke-free legislation on the 26 March 2006. A total of 371 bar workers were recruited from 72 bars in three cities: Aberdeen, Glasgow, Edinburgh and small towns in two rural regions (Borders and Aberdeenshire). Prior to the introduction of the smoke-free legislation, we visited all participants in their place of work and collected saliva samples, for the measurement of cotinine, together with details on work patterns, self-reported exposure to SHS at work and non-work settings and smoking history. This was repeated 2 months post-legislation and again in the spring of 2007. In addition, we gathered full-shift personal exposure data from a small number of Aberdeen bar workers using a personal aerosol monitor for fine particulate matter (PM(2.5)) at the baseline and 2 months post-legislation visits. Data were available for 371 participants at baseline, 266 (72%) at 2 months post-legislation and 191 (51%) at the 1-year follow-up. The salivary cotinine level recorded in non-smokers fell from a geometric mean of 2.94 ng ml(-1) prior to introduction of the legislation to 0.41 ng ml(-1) at 1-year follow-up. Paired data showed a reduction in non-smokers' cotinine levels of 89% [95% confidence interval (CI) 85-92%]. For the whole cohort, the duration of workplace exposure to SHS within the last 7 days fell from 28.5 to 0.83 h, though some bar workers continued to report substantial SHS exposures at work despite the legislation. Smokers also demonstrated reductions in their salivary cotinine levels of 12% (95% CI 3-20%). This may reflect both the reduction in SHS exposure at work and falls in active cigarette smoking in this group. In a small sub-sample of bar workers, full-shift personal exposure to PM(2.5), a marker of SHS concentrations, showed average reductions of 86% between baseline and 2 months after implementation of the legislation. Most bar workers have experienced very large reductions in their workplace exposure to SHS as a result of smoke-free legislation in Scotland. These reductions have been sustained over a period of 1 year.

Occupational Health Management in the Lead Industry: The Korean Experience

PubMed Central

2011-01-01

In 1967, the problem of occupational lead exposure came to public attention in Korea. Since then, regular progress has been made in lowering workplace lead exposures, instituting new workplace controls, and implementing health examinations of exposed workers. Past serious lead poisoning episodes made it possible to introduce biological monitoring programs on a voluntary basis in high-lead-exposure facilities in Korea. Industry-specific occupational health services for lead workers in Korea during the last 22 years can be categorized into three phases. During the first phase (1988-1993), efforts were directed at increasing awareness among workers about the hazards of lead exposure, biological monitoring of blood zinc protoporphyrin began, and a respiratory protection program was introduced. During the second phase (1994-1997), a computerized health management system for lead workers was developed, blood-lead measurement was added to biologic monitoring, and engineering controls were introduced in the workplace to lower air-lead levels to comply with air-lead regulations. Finally, during the third phase (1998-present), a new biomarker, bone-lead measurement by X-ray fluorescence, was introduced. Bone-lead measurement proved to be useful for assessing body burden and to demonstrate past lead exposure in retired workers. Occupational health service practice for lead workers, including the industry-specific group occupational health system, has brought considerable success in the prevention of lead poisoning and in reducing the lead burden in Korean lead workers during the last several decades. The successful achievement of prevention of lead poisoning in Korea was a result of the combined efforts of lead workers, employers, relevant government agencies, and academic institutes. PMID:22953192

Knockdown of p53 suppresses Nanog expression in embryonic stem cells

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

Abdelalim, Essam Mohamed, E-mail: emohamed@qf.org.qa; Molecular Neuroscience Research Center, Shiga University of Medical Science, Setatsukinowa-cho, Otsu, Shiga 520-2192; Department of Cytology and Histology, Faculty of Veterinary Medicine, Suez Canal University, Ismailia

2014-01-10

Highlights: •We investigate the role of p53 in ESCs in the absence of DNA damage. •p53 knockdown suppresses ESC proliferation. •p53 knockdown downregulates Nanog expression. •p53 is essential for mouse ESC self-renewal. -- Abstract: Mouse embryonic stem cells (ESCs) express high levels of cytoplasmic p53. Exposure of mouse ESCs to DNA damage leads to activation of p53, inducing Nanog suppression. In contrast to earlier studies, we recently reported that chemical inhibition of p53 suppresses ESC proliferation. Here, we confirm that p53 signaling is involved in the maintenance of mouse ESC self-renewal. RNA interference-mediated knockdown of p53 induced downregulation of p21more » and defects in ESC proliferation. Furthermore, p53 knockdown resulted in a significant downregulation in Nanog expression at 24 and 48 h post-transfection. p53 knockdown also caused a reduction in Oct4 expression at 48 h post-transfection. Conversely, exposure of ESCs to DNA damage caused a higher reduction of Nanog expression in control siRNA-treated cells than in p53 siRNA-treated cells. These data show that in the absence of DNA damage, p53 is required for the maintenance of mouse ESC self-renewal by regulating Nanog expression.« less

Tualang Honey Attenuates Noise Stress-Induced Memory Deficits in Aged Rats

PubMed Central

Azman, Khairunnuur Fairuz; Abdul Aziz, Che Badariah; Othman, Zahiruddin

2016-01-01

Ageing and stress exposure may lead to memory impairment while oxidative stress is thought to be one of the underlying mechanisms involved. This study aimed to investigate the potential protective effects of Tualang honey supplementation on memory performance in aged rats exposed to noise stress. Tualang honey supplementation was given orally, 200 mg/kg body weight for 28 days. Rats in the stress group were subjected to loud noise, 100 dB(A), 4 hours daily for 14 days. All rats were subjected to novel object recognition test for evaluation of memory performance. It was observed that the rats subjected to noise stress exhibited significantly lower memory performance and higher oxidative stress as evident by elevated malondialdehyde and protein carbonyl levels and reduction of antioxidant enzymes activities compared to the nonstressed rats. Tualang honey supplementation was able to improve memory performance, decrease oxidative stress levels, increase brain-derived neurotrophic factor (BDNF) concentration, decrease acetylcholinesterase activity, and enhance neuronal proliferation in the medial prefrontal cortex (mPFC) and hippocampus. In conclusion, Tualang honey protects against memory decline due to stress exposure and/or ageing via enhancement of mPFC and hippocampal morphology possibly secondary to reduction in brain oxidative stress and/or upregulation of BDNF concentration and cholinergic system. PMID:27119005

Evaluation of an Innovative Use of Removable Thin Film Coating Technology for the Abatement of Hazardous Contaminants

PubMed Central

Lumia, Margaret E.; Gentile, Charles; Gochfeld, Michael; Efthimion, Philip; Robson, Mark

2015-01-01

This study evaluates a new decontamination technique for the mitigation and abatement of hazardous particulates. The traditional decontamination methods used to clean facilities and equipment are time-consuming, prolonging workers' exposure time, may generate airborne hazards, and can be expensive. The use of removable thin film coating as a decontamination technique for surface contamination proved to be a more efficient method of decontamination. This method was tested at three different sites on different hazardous metals. One application of the coating reduced the levels of these metals 90% and had an average reduction of one magnitude. The paired t-tests that were performed for each metal demonstrated that there was a statistically significant reduction of the metal after the use of the coating: lead (p = 0.03), beryllium (p = 0.05), aluminum (p = 0.006), iron (p = 0.0001), and copper (p = 0.004). The Kendall tau-b correlation coefficient demonstrates that there was a positive correlation between the initial levels of contamination and the removal efficiency for all the samples taken from different locations on the floor for each of the three sites. This new decontamination technique worked efficiently, requiring only one application, which decreased exposure time and did not generate any airborne dust. PMID:19437305

Intraoral radiology in general dental practices - a comparison of digital and film-based X-ray systems with regard to radiation protection and dose reduction.

PubMed

Anissi, H D; Geibel, M A

2014-08-01

The purpose of this study was to gain insight into the distribution and application of digital intraoral radiographic techniques within general dental practices and to compare these with film-based systems in terms of patient dose reduction. 1100 questionnaires were handed out to general dental practitioners. Data was analyzed with respect to the type of system by using descriptive statistics and nonparametric tests, i.e. Kruskal-Wallis, Mann-Whitney and chi-square test (SPSS 20). 64% of the questioned dentists still use film-based radiology, 23% utilize storage phosphor plate (SPP) systems and 13% use a charge-coupled device (CCD). A strong correlation between the number of dentists working in a practice and the use of digital dental imaging was observed. Almost 3/4 of the film users work with E- or F-speed film. 45% of them refuse to change to a digital system. The use of lead aprons was popular, while only a minority preferred thyroid shields and rectangular collimators. A fourfold reduction of exposure time from D-speed film to CCD systems was observed. Due to detector size and positioning errors, users of CCD systems take significantly more single-tooth radiographs in total. Considering the number of radiographs per patient, there is only a slight tendency towards more X-rays with CCD systems. Up to image generation, digital systems seem to be as or even more difficult to handle than film-based systems, while their handling was favored after radiographic exposure. Despite a slight increase of radiographs taken with CCD systems, there is a significant dosage reduction. Corresponding to the decrease in exposure time, the patient dose for SPP systems is reduced to one half compared to film. The main issues in CCD technology are positioning errors and the size of the X-ray detectors which are difficult to eliminate. The usage of radiation protection measures still needs to be improved. ► Responsible use of digital intraoral radiology results in a significant dose reduction in everyday practice. ► The ALARA principle is only achieved by strict implementation of dose-reducing methods. ► The efforts to use dose-reducing devices must be increased. © Georg Thieme Verlag KG Stuttgart · New York.

Whole-Body Proton Irradiation Causes Long-Term Damage to Hematopoietic Stem Cells in Mice

PubMed Central

Chang, Jianhui; Feng, Wei; Wang, Yingying; Luo, Yi; Allen, Antiño R.; Koturbash, Igor; Turner, Jennifer; Stewart, Blair; Raber, Jacob; Hauer-Jensen, Martin; Zhou, Daohong; Shao, Lijian

2016-01-01

Space flight poses certain health risks to astronauts, including exposure to space radiation, with protons accounting for more than 80% of deep-space radiation. Proton radiation is also now being used with increasing frequency in the clinical setting to treat cancer. For these reasons, there is an urgent need to better understand the biological effects of proton radiation on the body. Such improved understanding could also lead to more accurate assessment of the potential health risks of proton radiation, as well as the development of improved strategies to prevent and mitigate its adverse effects. Previous studies have shown that exposure to low doses of protons is detrimental to mature leukocyte populations in peripheral blood, however, the underlying mechanisms are not known. Some of these detriments may be attributable to damage to hematopoietic stem cells (HSCs) that have the ability to self-renew, proliferate and differentiate into different lineages of blood cells through hematopoietic progenitor cells (HPCs). The goal of this study was to investigate the long-term effects of low-dose proton irradiation on HSCs. We exposed C57BL/6J mice to 1.0 Gy whole-body proton irradiation (150 MeV) and then studied the effects of proton radiation on HSCs and HPCs in the bone marrow (BM) 22 weeks after the exposure. The results showed that mice exposed to 1.0 Gy whole-body proton irradiation had a significant and persistent reduction of BM HSCs compared to unirradiated controls. In contrast, no significant changes were observed in BM HPCs after proton irradiation. Furthermore, irradiated HSCs and their progeny exhibited a significant impairment in clonogenic function, as revealed by the cobblestone area-forming cell (CAFC) and colony-forming cell assays, respectively. These long-term effects of proton irradiation on HSCs may be attributable to the induction of chronic oxidative stress in HSCs, because HSCs from irradiated mice exhibited a significant increase in NADPH oxidase 4 (NOX4) mRNA expression and reactive oxygen species (ROS) production. In addition, the increased production of ROS in HSCs was associated with a significant reduction in HSC quiescence and an increase in DNA damage. These findings indicate that exposure to proton radiation can lead to long-term HSC injury, probably in part by radiation-induced oxidative stress. PMID:25635345

Alterations of apparent diffusion coefficient (ADC) in the brain of rats chronically exposed to lead acetate.

PubMed

López-Larrubia, Pilar; Cauli, Omar

2011-03-15

Diffusion-weighted imaging (DWI) allows the assessment of the water apparent diffusion coefficient (ADC), a measure of tissue water diffusivity which is altered during different pathological conditions such as cerebral oedema. By means of DWI, we repeatedly measured in the same rats apparent diffusion coefficient ADC in different brain areas (motor cortex (MCx), somato-sensory cortex (SCx), caudate-putamen (CPu), hippocampus (Hip), mesencephalic reticular formation (RF), corpus callosum (CC) and cerebellum (Cb)) after 1 week, 4 and 12 weeks of lead acetate exposure via drinking water (50 or 500 ppm). After 12 weeks of lead exposure rats received albumin-Evans blue complex administration and were sacrificed 1h later. Blood-brain barrier permeability and water tissue content were determined in order to evaluate their relationship with ADC changes. Chronic exposure to lead acetate (500 ppm) for 4 weeks increased ADC values in Hip, RF and Cb but no in other brain areas. After 12 weeks of lead acetate exposure at 500 ppm ADC is significantly increased also in CPu and CC. Brain areas displaying high ADC values after lead exposure showed also an increased water content and increased BBB permeability to Evans blue-albumin complex. Exposure to 50 ppm for 12 weeks increased ADC values and BBB permeability in the RF and Cb. In summary, chronic lead exposure induces cerebral oedema in the adult brain depending on the brain area and the dose of exposure. RF and Cb appeared the most sensitive brain areas whereas cerebral cortex appears resistant to lead-induced cerebral oedema. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Cigarette smoke exposure reveals a novel role for the MEK/ERK1/2 MAPK pathway in regulation of CFTR

PubMed Central

Xu, Xiaohua; Balsiger, Robert; Tyrrell, Jean; Boyaka, Prosper N.; Tarran, Robert; Cormet-Boyaka, Estelle

2015-01-01

Background CFTR plays a key role in maintenance of lung fluid homeostasis. Cigarette smoke decreases CFTR expression in the lung but neither the mechanisms leading to CFTR loss, nor potential ways to prevent its loss have been identified to date. Methods The molecular mechanisms leading to down-regulation of CFTR by cigarette smoke were determined using pharmacologic inhibitors and silencing RNAs. Results Using human bronchial epithelial cells, here we show that cigarette smoke induces degradation of CFTR that is attenuated by the lysosomal inhibitors, but not proteasome inhibitors. Cigarette smoke can activate multiple signaling pathways in airway epithelial cells, including the MEK/Erk1/2 MAPK pathway regulating cell survival. Interestingly, pharmacological inhibition of the MEK/Erk1/2 MAPK pathway prevented the loss of plasma membrane CFTR upon cigarette smoke exposure. Similarly, decreased expression of Erk1/2 using silencing RNAs prevented the suppression of CFTR protein by cigarette smoke. Conversely, specific inhibitors of the JNK or p38 MAPK pathways had no effect on CFTR decrease after cigarette smoke exposure. In addition, inhibition of the MEK/Erk1/2 MAPK pathway prevented the reduction of the airway surface liquid observed upon cigarette smoke exposure of primary human airway epithelial cells. Finally, addition of the antioxidant NAC inhibited activation of Erk1/2 by cigarette smoke and precluded the cigarette smoke-induced decrease of CFTR. Conclusions These results show that the MEK/Erk1/2 MAPK pathway regulates plasma membrane CFTR in human airway cells. General Significance The MEK/Erk1/2 MAPK pathway should be considered as a target for strategies to maintain/restore CFTR expression in the lung of smokers. PMID:25697727

Climate change and our environment: the effect on respiratory and allergic disease.

PubMed

Barne, Charles; Alexis, Neil E; Bernstein, Jonathan A; Cohn, John R; Demain, Jeffrey G; Horner, Elliot; Levetin, Estelle; Nei, Andre; Phipatanakul, Wanda

2013-03-01

Climate change is a constant and ongoing process. It is postulated that human activities have reached a point at which we are producing global climate change. It provides suggestions to help the allergist/environmental physician integrate recommendations about improvements in outdoor and indoor air quality and the likely response to predicted alterations in the earth's environment into his or her patient's treatment plan. It incorporates references retrieved from Pub Med searches for topics, including:climate change, global warming, global climate change, greenhouse gasses, air pollution, particulates, black carbon, soot and sea level, as well as references contributed by the individual authors. Many changes that affect respiratory disease are anticipated.Examples of responses to climate change include energy reduction retrofits in homes that could potentially affect exposure to allergens and irritants, more hot sunny days that increase ozone-related difficulties, and rises in sea level or altered rainfall patterns that increase exposure to damp indoor environments.Climate changes can also affect ecosystems, manifested as the appearance of stinging and biting arthropods in new areas.Higher ambient carbon dioxide concentrations, warmer temperatures, and changes in floristic zones could potentially increase exposure to ragweed and other outdoor allergens,whereas green practices such as composting can increase allergen and irritant exposure. Finally, increased energy costs may resultin urban crowding and human source pollution, leading to changes in patterns of infectious respiratory illnesses. Improved governmental controls on airborne pollutants could lead to cleaner air and reduced respiratory diseases but will meet strong opposition because of their effect on business productivity. The allergy community must therefore adapt, as physician and research scientists always have, by anticipating the needs of patients and by adopting practices and research methods to meet changing environmental conditions.

Environmental lead exposure: a public health problem of global dimensions.

PubMed Central

Tong, S.; von Schirnding, Y. E.; Prapamontol, T.

2000-01-01

Lead is the most abundant of the heavy metals in the Earth's crust. It has been used since prehistoric times, and has become widely distributed and mobilized in the environment. Exposure to and uptake of this non-essential element have consequently increased. Both occupational and environmental exposures to lead remain a serious problem in many developing and industrializing countries, as well as in some developed countries. In most developed countries, however, introduction of lead into the human environment has decreased in recent years, largely due to public health campaigns and a decline in its commercial usage, particularly in petrol. Acute lead poisoning has become rare in such countries, but chronic exposure to low levels of the metal is still a public health issue, especially among some minorities and socioeconomically disadvantaged groups. In developing countries, awareness of the public health impact of exposure to lead is growing but relatively few of these countries have introduced policies and regulations for significantly combating the problem. This article reviews the nature and importance of environmental exposure to lead in developing and developed countries, outlining past actions, and indicating requirements for future policy responses and interventions. PMID:11019456

Brief Counseling on Secondhand Smoke Exposure in Pregnant Women in Argentina and Uruguay.

PubMed

Alemán, Alicia; Morello, Paola; Colomar, Mercedes; Llambi, Laura; Berrueta, Mabel; Gibbons, Luz; Buekens, Pierre; Althabe, Fernando

2016-12-29

Argentina and Uruguay have a high prevalence of smoking during pregnancy, as well as of secondhand smoke (SHS) exposure. In this secondary analysis of a trial to implement brief smoking cessation counseling during antenatal care in Argentina and Uruguay, we aim to evaluate the effects of the intervention on the rates of self-reported SHS exposure at home and at work, and on attitudes recalled by non-smoker women enrolled in the intervention group compared with the control group. We randomly assigned (1:1) 20 antenatal care clusters in Argentina and Uruguay to receive a multifaceted intervention to implement brief smoking cessation counseling, which also included questions and counseling regarding SHS exposure, or to receive the standard of care. There was not a statistically significant difference between groups of the intervention's effect (reduction of exposure to SHS) on any of the three exposure outcome measures (exposure at home, work or other indoor areas) or on the attitudes of women regarding exposure (avoiding breathing SHS and having rooms where smoking is forbidden). This analysis shows that we should not expect reductions in SHS exposure with this modest intervention alone. To achieve such reductions, strategies engaging partners and other household members may be more effective.

Protecting Children from Exposure to Lead: Old Problem, New Data, and New Policy Needs. Social Policy Report. Volume 24, Number 1

ERIC Educational Resources Information Center

Cole, Claire; Winsler, Adam

2010-01-01

The detrimental effects of lead exposure in children have been known for over 100 years. Although a few initial measures implemented about 30 years ago were effective in somewhat reducing levels of lead exposure in children, relatively little has been done recently from a policy perspective to protect children from lead. We now know from recent…

Early Childhood Lead Exposure and Academic Achievement: Evidence From Detroit Public Schools, 2008–2010

PubMed Central

Baker, Harolyn W.; Tufts, Margaret; Raymond, Randall E.; Salihu, Hamisu; Elliott, Michael R.

2013-01-01

Objectives. We assessed the long-term effect of early childhood lead exposure on academic achievement in mathematics, science, and reading among elementary and junior high school children. Methods. We linked early childhood blood lead testing surveillance data from the Detroit Department of Health and Wellness Promotion to educational testing data from the Detroit, Michigan, public schools. We used the linked data to investigate the effect of early childhood lead exposure on academic achievement among school-aged children, both marginally and adjusted for grade level, gender, race, language, maternal education, and socioeconomic status. Results. High blood lead levels before age 6 years were strongly associated with poor academic achievement in grades 3, 5, and 8. The odds of scoring less than proficient for those whose blood lead levels were greater than 10 micrograms per deciliter were more than twice the odds for those whose blood lead levels were less than 1 micrograms per deciliter after adjustment for potential confounders. Conclusions. Early childhood lead exposure was negatively associated with academic achievement in elementary and junior high school, after adjusting for key potential confounders. The control of lead poisoning should focus on primary prevention of lead exposure in children and development of special education programs for students with lead poisoning. PMID:23327265

Cognitive development and low-level lead exposure in poly-drug exposed children.

PubMed

Min, Meeyoung O; Singer, Lynn T; Kirchner, H Lester; Minnes, Sonia; Short, Elizabeth; Hussain, Zehra; Nelson, Suchitra

2009-01-01

The impact of early postnatal lead exposure measured at age 4 on children's IQ and academic achievement at and 11 years of age was examined. The sample consisted of 278 inner-city, primarily African American children who were polydrug exposed prenatally. Regression analyses indicated a linear effect of lead exposure on outcomes and no moderating effects of polydrug exposure. An IQ loss of about 4.1-5.4 Full Scale IQ points was estimated for each 10 microg/dL increase in blood lead level at ages 4, 9, and 11 years as a function of blood lead level at age 4. Decrements in scores on tests of non-verbal reasoning were consistently associated with higher lead levels at age 4, while verbal decrements became apparent only at age 11. Lower reading summary scores at 9 and 11 years were consistently associated with higher lead exposure, while decrements in mathematics were not apparent until 11 years. Subgroup analyses on children with blood lead levels <10 microg/dL showed detrimental lead effects even at the 5 microg/dL level, providing additional evidence of adverse effects occurring at blood lead levels below the current 10 microg/dL public health blood lead action level.

Determination of exposure to lead of subjects from southwestern Poland by human hair analysis.

PubMed

Michalak, Izabela; Wołowiec, Paulina; Chojnacka, Katarzyna

2014-04-01

The aim of the present work was to investigate the exposure to lead from various sources by investigation of mineral composition of human scalp hair. The research was carried out on hair sampled from 267 young adults living in Wrocław (southwest Poland). The effect of the place of residence, diet, and lifestyle on lead content in hair was examined by inductively coupled plasma optical emission spectrometry (ICP-OES). Lead was determined at the wavelength 220.353 nm. These outcomes were reached by linking the results of lead level in hair with the results of questionnaire survey. The mean lead level in hair of the whole examined population was 2.01 ± 2.10 mg kg(-1). Lead can enter the human body mainly by inhalation and gastrointestinal absorption. It was found that consuming cheese, fish, and lettuce caused increased level of lead in hair. On the other hand, drinking of milk, tea, coffee, or lemon resulted in decreased content of lead in hair. Additional source of exposure to lead could be cigarette smoking, distance to the traffic road, painting the walls, amalgam filling. Based on the results, it can be concluded that exposure to lead can occur mainly from eating habits and environmental exposure.

Cognitive Development and Low-Level Lead Exposure in Poly-Drug Exposed Children

PubMed Central

Min, Meeyoung O.; Singer, Lynn T.; Kirchner, H. Lester; Minnes, Sonia; Short, Elizabeth; Hussain, Zehra; Nelson, Suchitra

2009-01-01

The impact of early postnatal lead exposure measured at age 4 on children’s IQ and academic achievement at 4, 9, and 11 years of age was examined. The sample consisted of 278 inner-city, primarily African American children who were polydrug exposed prenatally. Regression analyses indicated a linear effect of lead exposure on outcomes and no moderating effects of polydrug exposure. An IQ loss of about 4.1–5.4 Full Scale IQ points was estimated for each 10 ug/dl increase in blood lead level at ages 4, 9, and 11 years as a function of blood lead level at age 4. Decrements in scores on tests of non-verbal reasoning were consistently associated with higher lead levels at age 4, while verbal decrements became apparent only at age 11. Lower reading summary scores at 9 and 11 years were consistently associated with higher lead exposure, while decrements in mathematics were not apparent until 11 years. Subgroup analyses on children with blood lead levels < 10 μg/dL showed detrimental lead effects even at the 5 μg/dL level, providing additional evidence of adverse effects occurring at blood lead levels below the current 10 μg/dL public health blood lead action level. PMID:19345261

Olfactory recognition memory is disrupted in young mice with chronic low-level lead exposure

PubMed Central

Flores-Montoya, Mayra Gisel; Alvarez, Juan Manuel; Sobin, Christina

2015-01-01

Chronic developmental lead exposure yielding very low blood lead burden is an unresolved child public health problem. Few studies have attempted to model neurobehavioral changes in young animals following very low level exposure, and studies are needed to identify tests that are sensitive to the neurobehavioral changes that may occur. Mechanisms of action are not yet known however results have suggested that hippocampus/dentate gyrus may be uniquely vulnerable to early chronic low-level lead exposure. This study examined the sensitivity of a novel odor recognition task to differences in pre-adolescent C57BL/6J mice chronically exposed from birth to PND 28, to 0 ppm (control), 30 ppm (low-dose), or 330 ppm (higher-dose) lead acetate (N = 33). Blood lead levels (BLLs) determined by ICP-MS ranged from 0.02 to 20.31 µg/dL. Generalized linear mixed model analyses with litter as a random effect showed a significant interaction of BLL × sex. As BLLs increased olfactory recognition memory decreased in males. Among females, non-linear effects were observed at lower but not higher levels of lead exposure. The novel odor detection task is sensitive to effects associated with early chronic low-level lead exposure in young C57BL/6J mice. PMID:25936521

Measuring Lead Exposure in Infants, Children, and Other Sensitive Populations.

ERIC Educational Resources Information Center

National Academy of Sciences - National Research Council, Washington, DC.

Adverse health effects from exposure to lead are now recognized to be among industrialized society's most important health problems. This report, prepared by the National Research Council's Committee on Measuring Lead Exposure in Critical Populations, concurs with new findings issued by the Centers for Disease Control which state that lead…

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

Mathee, Angela

Introduction: Lead exposure in shooting ranges has been under scrutiny for decades, but no information in this regard is available in respect of African settings, and in South Africa specifically. The aim of this study was to determine the blood lead levels in the users of randomly selected private shooting ranges in South Africa's Gauteng province. Methods: An analytical cross sectional study was conducted, with participants recruited from four randomly selected shooting ranges and three archery ranges as a comparator group. Results: A total of 118 (87 shooters and 31 archers) were included in the analysis. Shooters had significantly highermore » blood lead levels (BLL) compared to archers with 36/85 (42.4%) of shooters versus 2/34 (5.9%) of archers found to have a BLL ≥10 μg/dl (p<0.001). Conclusion: Shooting ranges may constitute an import site of elevated exposure to lead. Improved ventilation, low levels of awareness of lead hazards, poor housekeeping, and inadequate personal hygiene facilities and practices at South African shooting ranges need urgent attention. - Highlights: • This is the first study, to our knowledge, of lead exposure in shooting ranges in an African setting. • This study indicates highly elevated lead exposure amongst the users of certain private shooting ranges in South Africa. • Lead exposure may be a serious, yet under-studied, source of adult lead exposure in South Africa, and possibly elsewhere on the African continent.« less

Assessment of Lead Exposure Risk in Locksmiths

PubMed Central

Kondrashov, Vladislav; McQuirter, Joseph L.; Miller, Melba; Rothenberg, Stephen J.

2005-01-01

Exposure to lead has been well recognized in a number of work environments, but little is known about lead exposure associated with machining brass keys containing lead. The brass that is widely used for key manufacturing usually contains 1.5% – 2.5 % of lead. Six (6) licensed locksmiths and 6 case-matched controls successfully completed the pilot study to assess the prevalence of increased body lead burden of professional locksmiths. We measured both Blood Lead (atomic absorption spectrometry), bone-lead (KXRF) and had each subject complete a health and lead exposure risk questionnaire. One locksmith had not cut keys during the past two years, therefore this subject and case-matched control was excluded from the blood lead analysis only. The average blood-lead concentration (±SEM) for the 5 paired subjects was 3.1 (± 0.4) μg/dL and 2.2 (± 0.3) μg /dL for controls. Bone measurements, including all 6 paired subjects, showed tibia lead concentration (±SEM) for locksmiths and controls was 27.8 (± 2.3) μg /g and 13.7 (± 3.3) μg /g, respectively; average calcaneus lead concentration for locksmiths and controls was 31.9 (± 3.7) μg /g and 22.6 (± 4.1) μg /g, respectively: The t-test shows a significantly higher tibia lead (p<0.05) and blood lead (p<0.05) for locksmiths than for their matched controls, but no significant difference for calcaneus lead (p>0.10). Given that the mean tibia bone lead concentration was 13.1μg/g higher in locksmiths than in their matched controls, this average difference in the two groups would translate to an OR of increased hypertension in locksmiths of between 1.1 and 2.3, based on the published literature. Even with the very small number of subjects participating in this pilot study, we were able to demonstrate that locksmiths had significantly higher current exposure to lead (blood lead concentration) and significantly higher past exposure to lead (tibia lead concentration) than their age, sex and ethnically matched controls. Additional research is needed to fully identify the prevalence and associated risk factors for occupational exposure of lead in this previously understudied profession. PMID:16705814

Effect of Exposure on the Mechanical Properties of Gamma MET PX

NASA Technical Reports Server (NTRS)

Draper, S. L.; Lerch, B. A.; Locci, I. E.; Shazly, M.; Prakash, V.

2004-01-01

The effect of a service environment exposure on the mechanical properties of a high Nb content TiAl alloy, Gamma MET PX , was assessed. Gamma MET PX, like other TiAl alloys, experiences a reduction of ductility following high temperature exposure. Exposure in Ar, air, and high-purity oxygen all resulted in a loss of ductility with the ductility reduction increasing with oxygen content in the exposure atmosphere. Embrittling mechanisms, including bulk microstructural changes, moisture induced environmental embrittlement, and near surface effects were investigated. The embrittlement has been shown to be a near-surface effect, most likely due to the diffusion of oxygen into the alloy.

A new understanding of multiple-pulsed laser-induced retinal injury thresholds.

PubMed

Lund, David J; Sliney, David H

2014-04-01

Laser safety standards committees have struggled for years to formulate adequately a sound method for treating repetitive-pulse laser exposures. Safety standards for lamps and LEDs have ignored this issue because averaged irradiance appeared to treat the issue adequately for large retinal image sizes and skin exposures. Several authors have recently questioned the current approach of three test conditions (i.e., limiting single-pulse exposure, average irradiance, and a single-pulse-reduction factor) as still insufficient to treat pulses of unequal energies or certain pulse groupings. Schulmeister et al. employed thermal modeling to show that a total-on-time pulse (TOTP) rule was conservative. Lund further developed the approach of probability summation proposed by Menendez et al. to explain pulse-additivity, whereby additivity is the result of an increasing probability of detecting injury with multiple pulse exposures. This latter argument relates the increase in detection probability to the slope of the probit curve for the threshold studies. Since the uncertainty in the threshold for producing an ophthalmoscopically detectable minimal visible lesion (MVL) is large for retinal exposure to a collimated laser beam, safety committees traditionally applied large risk reduction factors ("safety factors") of one order of magnitude when deriving intrabeam, "point-source" exposure limits. This reduction factor took into account the probability of visually detecting the low-contrast lesion among other factors. The reduction factor is smaller for large spot sizes where these difficulties are quite reduced. Thus the N⁻⁰·²⁵ reduction factor may result from the difficulties in detecting the lesion. Recent studies on repetitive pulse exposures in both animal and in vitro (retinal explant) models support this interpretation of the available data.

Lead Surveillance Program

NASA Technical Reports Server (NTRS)

1993-01-01

Background on lead exposure is presented including forms of lead, sources, hematologic effects, neurologic effects, endocrine effects, renal effects, and reproductive and developmental effects. The purpose of the Lead Surveillance Program at LeRC is outlined, and the specifics of the Medical Surveillance Program for Lead Exposure at LeRC are discussed.

Developmental effects of exposures to environmental factors: the Polish Mother and Child Cohort Study.

PubMed

Polanska, Kinga; Hanke, Wojciech; Sobala, Wojciech; Trzcinka-Ochocka, Malgorzata; Ligocka, Danuta; Brzeznicki, Slawomir; Strugala-Stawik, Halina; Magnus, Per

2013-01-01

This paper estimates the effects of exposure to environmental factors, including lead, mercury, environmental tobacco smoke (ETS), and polycyclic aromatic hydrocarbons (PAH), on child psychomotor development. The study population consists of mother-child pairs in the Polish Mother and Child Cohort Study. Prenatal and postnatal exposure to environmental factors was determined from biomarker measurements as follows: for lead exposure--cord blood lead level, for mercury--maternal hair mercury level, for ETS--cotinine level in saliva and urine, and for PAH--1-hydroxypyrene (1-HP) in urine. At the age of 12 (406 subjects) and 24 months (198 subjects) children were assessed using Bayley Scales of Infant and Toddler Development. There were no statistically significant effects of prenatal exposure to mercury or 1-HP on child psychomotor development. After adjusting for potential confounders, adverse effects of prenatal exposure to ETS on motor development ( β = -2.6; P = 0.02) and postnatal exposure to ETS on cognitive ( β = -0.2; P = 0.05) and motor functions ( β = -0.5; P = 0.01) were found. The adverse effect of prenatal lead exposure on cognitive score was of borderline significance ( β = -6.2; P = 0.06). The study underscores the importance of policies and public health interventions that aim to reduce prenatal and postnatal exposure to lead and ETS.

Cadmium: Simulation of environmental control strategies to reduce exposure

NASA Astrophysics Data System (ADS)

Yost, K. J.; Miles, L. J.; Greenkorn, R. A.

1981-07-01

The effects of selected environmental control strategies on human dietary and respiratory exposure to environmental cadmium (Cd) have been simulated. For each control strategy, mean Cd dietary and respiratory exposures are presented for a twenty-year simulation period. Human exposures related to cadmium are associated with both process waste disposal and product disposal. Dietary exposure is by far the dominant mechanism for Cd intake. Dietary exposure related to aqueous discharges is primarily a result of municipal sludge landspreading, whereas that associated with emissions to the atmosphere derives mainly from the deposition on cropland of airborne particulates from product incineration. Only relatively small dietary exposure reductions are possible through restrictions on any single Cd use. Combinations of waste management and environmental control measures promise greater reductions in dietary and respiratory exposure than those achievable through use restrictions.

External lead contamination of women's nails by surma in Pakistan: Is the biomarker reliable?

PubMed

Ikegami, Akihiko; Takagi, Mai; Fatmi, Zafar; Kobayashi, Yayoi; Ohtsu, Mayumi; Cui, Xiaoyi; Mise, Nathan; Mizuno, Atsuko; Sahito, Ambreen; Khoso, Aneeta; Kayama, Fujio

2016-11-01

Adverse health effects of heavy metals are a public health concern, especially lead may cause negative health impacts to human fetal and infantile development. The lead concentrations in Pakistani pregnant women's nails, used as a biomarker, were measured to estimate the lead exposure. Thirteen nail samples out of 84 nails analyzed contained lead higher than the concentration (13.6 μg/g) of the fatal lead poisoning case, raising the possibility of an external contamination. Eye cosmetics such as surma are recognized as one of the important sources of lead exposure in Pakistan. We collected in Pakistan 30 eye cosmetics made in Pakistan, Saudi Arabia and western countries. As the metal composition analysis by energy dispersive X-ray fluorescence spectrometry revealed that some surma samples contained lead more than 96%, the surma might contaminate the nail specimen. Scanning electron microscopy observations showed that lead-containing surma consists of fine particle of galena (ore of lead sulfide) in respirable dust range (less than 10 μm). In addition, relative in vitro bioavailability of lead in the surma was determined as 5.2%. Thus, lead-containing surma consists of inhalable and bioavailable particles, and it contributes an increased risk of lead exposure. Moreover, the relationship between the surma and the lead-contaminated nails by lead isotope ratios analysis indicated the potential of lead contamination in nails by surma. These results suggest that lead in the nails was derived both from body burden of lead and external contamination by lead-containing surma. Therefore, nail is not suited as a biomarker for lead exposure in the countries where surma used, because we may overestimate lead exposure by surface lead contamination in the nail by surma. Copyright © 2016 Elsevier Ltd. All rights reserved.

Childhood lead exposure and sexually transmitted infections: New evidence.

PubMed

Nelson, Erik J; Shacham, Enbal; Boutwell, Brian B; Rosenfeld, Richard; Schootman, Mario; Vaughn, Michael; Lewis, Roger

2015-11-01

The adverse health effects of lead exposure in children are well documented and include intellectual and behavioral maladies. Childhood lead exposure has also been linked to impulsive behaviors, which, in turn, are associated with a host of negative health outcomes including an increased risk for sexually transmitted infections (STI). The purpose of this study was to assess the association of lead exposure with STI rates across census tracts in St. Louis City, Missouri. Incident cases of gonorrhea and chlamydia (GC) during 2011 were identified from the Missouri Department of Health and Senior Services and aggregated by census tract. We also geocoded the home address of 59,645 children >72 months in age who had blood lead level tests performed in St. Louis City from 1996 to 2007. Traditional regression and Bayesian spatial models were used to determine the relationship between GC and lead exposure while accounting for confounders (condom and alcohol availability, crime, and an index of concentrated disadvantage). Incident GC rates were found to cluster across census tracts (Moran's I=0.13, p=0.006). After accounting for confounders and their spatial dependence, a linear relationship existed between lead exposure and GC incidence across census tracts, with higher GC rates occurring in the northern part of St. Louis City At the census-tract level, higher lead exposure is associated with higher STI rates. Visualizing these patterns through maps may help deliver targeted interventions to reduce geographic disparities in GC rates. Copyright © 2015 Elsevier Inc. All rights reserved.

Levels of blood lead and urinary cadmium in industrial complex residents in Ulsan.

PubMed

Kim, Sang Hoon; Kim, Yang Ho; An, Hyun Chan; Sung, Joo Hyun; Sim, Chang Sun

2017-01-01

Populations neighboring industrial complexes are at an increased health risk, due to constant exposure to various potentially hazardous compounds released during industrial production activity. Although there are many previous studies that focus on occupational exposure to heavy metals, studies that focused on environmental exposure to lead and cadmium are relatively rare. The purpose of this study is to evaluate the extent of the environmental exposure of heavy metals in residents of industrial area. Four areas in close proximity to the Ulsan petrochemical industrial complex and the Onsan national industrial complex were selected to be included in the exposure group, and an area remotely located from these industrial complexes was selected as the non-exposure group. Among the residents of our study areas, a total of 1573 subjects aged 20 years and older were selected and all study subjects completed a written questionnaire. Blood and urine samples were obtained from about one third of the subjects (465 subjects) who provided informed consent for biological sample collection. Total 429 subjects (320 subjects from exposure area, 109 subjects from non-exposure area) were included in final analysis. The geometric mean blood lead level among the subjects in the exposed group was 2.449 μg/dL, which was significantly higher than the non-exposure group's level of 2.172 μg/dL. Similarly, the geometric mean urine cadmium levels between the two groups differed significantly, at 1.077 μg/g Cr. for the exposed group, and 0.709 μg/g Cr. for the non-exposure group. In a multiple linear regression analysis to determine the relationship between blood lead level and related factors, the results showed that blood lead level had a significant positive correlation with age, the male, exposure area, and non-drinkers. In the same way, urine cadmium level was positively correlated with age, the female, exposure area, and smokers. This study found that blood lead levels and urine cadmium levels were significantly higher among the residents of industrial areas than among the non-exposure area residents, which is thought to be due to the difference in environmental exposure of lead and cadmium. Furthermore, it was clear that at a low level of exposure, differences in blood lead or urine cadmium levels based on age, gender, and smoking status were greater than the differences based on area of residence. Therefore, when evaluating heavy metal levels in the body at a low level of exposure, age, gender, and smoking status must be adjusted, as they are significant confounding factors.

Site-specific lead exposure from lead pellet ingestion in sentinel mallards

USGS Publications Warehouse

Rocke, T.E.; Brand, C.J.; Mensik, John G.

1997-01-01

We monitored lead poisoning from the ingestion of spent lead pellets in sentinel mallards (Anas platyhrynchos) at the Sacramento National Wildlife Refuge (SNWR), Willows, California for 4 years (1986-89) after the conversion to steel shot for waterfowl hunting on refuges in 1986. Sentinel mallards were held in 1.6-ha enclosures in 1 hunted (P8) and 2 non-hunted (T19 and TF) wetlands. We compared site-specific rates of lead exposure, as determined by periodic measurement of blood lead concentrations, and lead poisoning mortality between wetlands with different lead pellet densities, between seasons, and between male and female sentinels. In 1986, the estimated 2-week rate of lead exposure was significantly higher (P < 0.005) in P8 (43.8%), the wetland with the highest density of spent lead pellets (>2,000,000 pellets/ha), than in those with lower densities of lead pellets, T19 (18.1%; 173,200 pellets/ha) and TF (0.9%; 15,750 pellets/ha). The probability of mortality from lead poisoning was also significantly higher (P < 0.01) in sentinel mallards enclosed in P8 (0.25) than T19 (0) and TF (0) in 1986 and remained significantly higher (P < 0.001) during the 4-year study. Both lead exposure and the probability of lead poisoning mortality in P8 were significantly higher (P < 0.001) in the fall of 1986 (43.8%; 0.25), before hunting season, than in the spring of 1987 (21.6%; 0.04), after hunting season. We found no significant differences in the rates of lead exposure or lead poisoning mortality between male and female sentinel mallards. The results of this study demonstrate that in some locations, lead exposure and lead poisoning in waterfowl will continue to occur despite the conversion to steel shot for waterfowl hunting.

Occupational exposure to airborne lead in Brazilian police officers.

PubMed

Rocha, Ernesto Díaz; Sarkis, Jorge E Souza; Carvalho, Maria de Fátima H; Santos, Gerson Vechio Dos; Canesso, Claudemir

2014-07-01

Shooting with lead-containing ammunition in indoor firing ranges is a known source of lead exposure in adults. Police officers may be at risk of lead intoxication when regular training shooting exercises are yearly mandatory to law enforcement officers. Effects on health must be documented, even when low-level elemental (inorganic) lead exposure is detected. Forty police officers (nineteen cadets and twenty-one instructors) responded to a questionnaire about health, shooting habits, and potential lead exposure before a training curse. Blood samples were collected and analyzed for blood lead level (BLL) before and after a three days training curse. The mean BLL for the instructors' group was 5.5 μg/dL ± 0.6. The mean BLL for the cadets' group before the training was 3.3 μg/dL ± 0.15 and after the training the main BLL was 18.2 μg/d L± 1.5. Samples were analyzed by Inductively Coupled Plasma Mass Spectrometer (ICP-MS). All the participants in the training curse had significantly increased BLL (mean increment about 15 μg/dL) after the three days indoor shooting season. In conclusion, occupational lead exposure in indoor firing ranges is a source of lead exposure in Brazilian police officers, and appears to be a health risk, especially when heavy weapons with lead-containing ammunition are used in indoor environments during the firing training seasons. Copyright © 2013 Elsevier GmbH. All rights reserved.

Control of excessive lead exposure in radiator repair workers.

PubMed

1991-03-01

In 1988, 83 automotive repair workers with blood lead levels (BLLs) greater than 25 micrograms/dL were reported to state health departments in the seven states that collaborated with CDC's National Institute for Occupational Safety and Health (NIOSH) in maintaining registries of elevated BLLs in adults. In 18 (22%) of these 83 persons, BLLs were greater than 50 micrograms/dL. Among automotive repair workers for whom a job category was specified, radiator repair work was the principal source of lead exposure. The major sources of exposure for radiator repair workers are lead fumes generated during soldering and lead dust produced during radiator cleaning. This report summarizes current BLL surveillance data for radiator repair workers and describes three control technologies that are effective in reducing lead exposures in radiator repair shops.

Levothyroxine rescues the lead-induced hypothyroidism and impairment of long-term potentiation in hippocampal CA1 region of the developmental rats

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

Wu Chuanyun; Liu Bing; Wang Huili

Lead (Pb) exposure during development has been associated with impaired long-term potentiation (LTP). Hypothyroidism happening upon subjects with occupational exposure to Pb is suggestive of an adverse effect of Pb on thyroid homeostasis, leading to the hypothesis that Pb exposure may alter thyroid hormone homeostasis. Hippocampus is one of the targets of Pb exposure, and is sensitive to and dependent on thyroid hormones, leading us to explore whether levothyroxine (L-T{sub 4}) administration could alter the thyroid disequilibrium and impairment of LTP in rat hippocampus caused by Pb exposure. Our results show that Pb exposure caused a decrease in triiodothyronine (T{submore » 3}) and tetraiodothyronine (T{sub 4}) levels accompanied by a dramatic decrease of TSH and application of L-T{sub 4} restored these changes to about control levels. Hippocampal and blood Pb concentration were significantly reduced following L-T{sub 4} treatment. L-T{sub 4} treatment rescued the impairment of LTP induced by the Pb exposure. These results suggest that Pb exposure may lead to thyroid dysfunction and induce hypothyroidism and provide a direct electrophysiological proof that L-T{sub 4} relieves chronic Pb exposure-induced impairment of synaptic plasticity. - Highlights: > Lead may interfere with thyroid hormone homeostasis and induce hypothyroidism. > Levothyroxine decreases the hippocampal and blood Pb concentration. > Levothyroxine amends the T{sub 3}, T{sub 4} and TSH levels in blood. > Levothyroxine rescues the impaired LTP in CA1.« less

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

Dobrakowski, Michał, E-mail: michal.dobrakowski@po

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

Early chronic lead exposure reduces exploratory activity in young C57BL/6J mice.

PubMed

Flores-Montoya, Mayra Gisel; Sobin, Christina

2015-07-01

Research has suggested that chronic low-level lead exposure diminishes neurocognitive function in children. Tests that are sensitive to behavioral effects at lowest levels of lead exposure are needed for the development of animal models. In this study we investigated the effects of chronic low-level lead exposure on exploratory activity (unbaited nose poke task), exploratory ambulation (open field task) and motor coordination (Rotarod task) in pre-adolescent mice. C57BL/6J pups were exposed to 0 ppm (controls), 30 ppm (low-dose) or 230 ppm (high-dose) lead acetate via dams' drinking water administered from birth to postnatal day 28, to achieve a range of blood lead levels (BLLs) from not detectable to 14.84 µg dl(-1) ). At postnatal day 28, mice completed behavioral testing and were killed (n = 61). BLLs were determined by inductively coupled plasma mass spectrometry. The effects of lead exposure on behavior were tested using generalized linear mixed model analyses with BLL, sex and the interaction as fixed effects, and litter as the random effect. BLL predicted decreased exploratory activity and no threshold of effect was apparent. As BLL increased, nose pokes decreased. The C57BL/6J mouse is a useful model for examining effects of early chronic low-level lead exposure on behavior. In the C57BL/6J mouse, the unbaited nose poke task is sensitive to the effects of early chronic low-level lead exposure. This is the first animal study to show behavioral effects in pre-adolescent lead-exposed mice with BLL below 5 µg dl(-1). Copyright © 2014 John Wiley & Sons, Ltd.

Early chronic lead exposure reduces exploratory activity in young C57BL/6J mice

PubMed Central

Flores-Montoya, Mayra Gisel; Sobin, Christina

2014-01-01

Research has suggested that chronic low-level lead exposure diminishes neurocognitive function in children. Tests that are sensitive to behavioral effects at lowest levels of lead exposure are needed for the development of animal models. In this study we investigated the effects of chronic low-level lead exposure on exploratory activity (unbaited nose poke task), exploratory ambulation (open field task) and motor coordination (Rotarod task) in pre-adolescent mice. C57BL/6J pups were exposed to 0 ppm (controls), 30 ppm (low-dose) or 230 ppm (high-dose) lead acetate via dams’ drinking water administered from birth to postnatal day 28, to achieve a range of blood lead levels (BLLs) from not detectable to 14.84 μg dl−1). At postnatal day 28, mice completed behavioral testing and were killed (n = 61). BLLs were determined by inductively coupled plasma mass spectrometry. The effects of lead exposure on behavior were tested using generalized linear mixed model analyses with BLL, sex and the interaction as fixed effects, and litter as the random effect. BLL predicted decreased exploratory activity and no threshold of effect was apparent. As BLL increased, nose pokes decreased. The C57BL/6J mouse is a useful model for examining effects of early chronic low-level lead exposure on behavior. In the C57BL/6J mouse, the unbaited nose poke task is sensitive to the effects of early chronic low-level lead exposure. This is the first animal study to show behavioral effects in pre-adolescent lead-exposed mice with BLL below 5 μg dl−1. PMID:25219894

E-Waste Informal Recycling: An Emerging Source of Lead Exposure in South America.

PubMed

Pascale, Antonio; Sosa, Adriana; Bares, Cristina; Battocletti, Alejandra; Moll, María José; Pose, Darío; Laborde, Amalia; González, Hugo; Feola, Gabriella

2016-01-01

Primitive electronic waste (e-waste) recycling creates exposures to several hazardous substances including lead. In Uruguay, primitive recycling procedures are a significant source of lead exposure. The aim of this study was to examine lead exposure in blood lead levels (BLLs) in low-income children exposed to lead through burning cables. A sample of children and adolescents exposed to lead through burning cable activities were assessed at the Department of Toxicology in Montevideo, Uruguay, between 2010 and 2014. Soil lead levels of residences were taken shortly after their assessment. The final sample included 69 children and adolescents (mean age 7.89 years). More than 66% of participants had an additional source of lead exposure-manual gathering of metals-and <5% were exposed to lead through landfills or paint. Average BLLs at first consultation were 9.19 ug/dL and lower at the second measurement (5.86 μg/dL). Data from soil lead levels ranged from 650 to 19,000 mg of lead/kg of soil. The interventions conducted after the assessment included family education in the clinic and at home, indoor and outdoor remediation. We found a decrease in BLLs of 6.96 μg/dL. Older children had lower BLLs (r = -0.24; P = 0.05). Statistical analyses also showed that children living in areas with higher soil lead levels had significantly higher BLLs (r = 0.50; P < 0.01). Additionally, we found greater BLLs from burning cable activities when children had been exposed to lead-based paint (r = 0.23; P < 0.1). Among children exposed to e-waste recycling, the most common additional source of lead exposure was the manual gathering of metals. The average BLL among children and adolescents in this study is higher than the BLLs currently suggested in medical intervention. Future research should focus on exploring effective interventions to reduce lead exposure among this vulnerable group. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Unintentional and Sequential Lead Exposure from a Ceramic Mug and Maca (Lepidium meyenii).

PubMed

Johnson-Arbor, Kelly; Vo, Kathy; Wong, Flavia; Gajek, Ryszard

2018-06-01

Although the incidence of lead poisoning has decreased in the USA over the last 30 years, human exposures to lead-containing products are still reported. We present a case of unintentional lead exposure from a store-bought ceramic mug and a nutritional supplement. A 32-year-old female was found to have a whole blood lead concentration of 44 μg/dL. Evaluation of her home, occupation, and hobbies initially did not identify a source of lead exposure. Further investigation revealed that the likely etiology of the exposure was lead leaching from a ceramic mug used by the patient to drink hot lemon water while she was pregnant. She stopped drinking from the mug and her blood lead levels decreased, but increased a year later after she began to ingest a maca root powder supplement. Upon discontinuation of maca root powder ingestion, her blood lead levels decreased further. Over time, the acidity and heat of the hot lemon water used in the ceramic mug enhanced the breakdown of its leaded glaze. Maca powder, which is available as a nutritional supplement and is used to treat fatigue and enhance fertility, may contain lead and other minerals. Consumers, particularly women of childbearing age, and their physicians should be aware that imported products available from commercial retailers and internet vendors may contain significant amounts of lead.

The Poisoning of America's Children: Lead Exposure, Children's Brains, and the Ability To Learn. National Health/Education Consortium Occasional Paper #6.

ERIC Educational Resources Information Center

Needleman, Herbert L.

Despite years of concern about the toxic effects of high lead exposure and recent knowledge about the less apparent effects of exposure to low doses of lead, a total of 3 to 4 million children in the United States are still being exposed to concentrations of lead that could compromise their cognitive and social development. This paper discusses:…

Relative effects of climate and source strength on atmospheric lead concentrations in Auckland, New Zealand

NASA Astrophysics Data System (ADS)

Power, H. C.; de Freitas, C. R.; Hay, J. E.

1992-06-01

Atmospheric lead levels were examined to assess the consequences of the 46 percent reduction in the lead content of premium grade petrol in New Zealand. Since this change was implemented in July 1986 observed levels of atmospheric lead decreased by 38 percent, but all or part of this reduction may have been due to factors other than fluctuations in lead emissions, notably variations in climate. Analysis of detailed atmospheric lead, meteorological and traffic data measured contemporaneously provided insight into the atmospheric processes influencing lead levels in Auckland and formed the basis of a statistical model capable of predicting monthly lead concentrations. The model was used to predict lead levels in Auckland for the period July 1986 through to July 1989 in the absence of any reduction in the lead content of petrol. Comparison with values observed for the same period showed that all of the reduction in atmospheric lead levels since July 1986 can be attributed to the reduction in the lead content of petrol. Policy planning implications of such a finding are considered.

Multimedia lead exposure and associated risk assessment in Dhaka, Bangladesh

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

Sarwar, M.

1998-12-31

Motor vehicles consume the largest amount of leaded gasoline in Bangladesh. The number of vehicles and fuel consumption have increased significantly in recent years. These vehicles, which are believed to be the major sources of lead emissions in Dhaka, may cause an excessive level of lead exposure in children. The paper describes the results of a study conducted to determine risk associated with the multimedia lead exposure for children in Dhaka. Specifically, data related to lead content in air and soil in Dhaka were collected and used to estimate the blood lead levels in children. The Integrated Exposure Uptake Biokineticsmore » Model, developed by the United States Environmental Protection Agency (USEPA), was used. Bangladesh is yet to adopt any blood lead standards. The results of the study indicated that the model predicted geometric blood lead levels in children in Dhaka are significantly below the blood lead standard recommended by the World Health Organization (WHO). It was also found that children in Dhaka are not expected to contain blood lead levels higher than the WHO recommended standard.« less

Investigation of Childhood Lead Poisoning from Parental Take-Home Exposure from an Electronic Scrap Recycling Facility — Ohio, 2012.

PubMed

Newman, Nick; Jones, Camille; Page, Elena; Ceballos, Diana; Oza, Aalok

2015-07-17

Lead affects the developing nervous system of children, and no safe blood lead level (BLL) in children has been identified. Elevated BLLs in childhood are associated with hyperactivity, attention problems, conduct problems, and impairment in cognition. Young children are at higher risk for environmental lead exposure from putting their hands or contaminated objects in their mouth. Although deteriorating lead paint in pre-1979 housing is the most common source of lead exposure in children, data indicate that ≥30% of children with elevated BLLs were exposed through a source other than paint. Take-home contamination occurs when lead dust is transferred from the workplace on employees' skin, clothing, shoes, and other personal items to their car and home. Recycling of used electronics (e-scrap) is a relatively recent source of exposure to developmental neurotoxicants, including lead. In 2010, the Cincinnati Health Department and Cincinnati Children's Hospital Pediatric Environmental Health Specialty Unit (PEHSU) investigated two cases of childhood lead poisoning in a single family. In 2012, CDC's National Institute for Occupational Safety and Health (NIOSH) learned about the lead poisonings during an evaluation of the e-scrap recycling facility where the father of the two children with lead poisoning worked. This report summarizes the case investigation. Pediatricians should ask about parents' occupations and hobbies that might involve lead when evaluating elevated BLLs in children, in routine lead screening questionnaires, and in evaluating children with signs or symptoms of lead exposure.

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.

Negative pressure wound therapy with instillation, a cost-effective treatment for abdominal mesh exposure.

PubMed

Deleyto, E; García-Ruano, A; González-López, J R

2018-04-01

Negative pressure wound therapy with instillation (NPWTi) has been proved to be a safe and effective treatment option for abdominal wall wound dehiscence with mesh exposure. Our aim in this study is to examine whether it is also cost-effective. We performed a retrospective cohort study with 45 patients treated for postoperative abdominal wall wound dehiscence and exposed mesh: 34 were treated with conventional wound therapy (CWT) and 11 with NPWTi. We carried out a cost analysis for each treatment group using the Diagnosis-related group (DRG) system and a second evaluation using the calculated costs "per hospital stay". The differences between NPWTi and CWT were calculated with both evaluation systems. Comparative analysis was performed using the Mann-Whitney U test. Mean costs using the DRG estimation were 29,613.71€ for the CWT group and 15,093.37€ for the NPWTi group, and according to the calculated expenses "per hospital stay", 17,322.88€ for the CWT group and 15,284.22€ for the NPWTi group. NPWTi showed a reduction in the total expense of treatment, related to a reduction in episodes of hospitalization and number of surgeries required to achieve wound closure. However, differences were not statistically significant in our sample. NPWTi proves to be an efficient treatment option for abdominal wall wound dehiscence with mesh exposure, compared to CWT. More trials aimed to optimize treatment protocols will lead to an additional increase in NPWTi efficiency. In addition, to generalize our results, further studies with larger samples would be necessary.

Characterizing Golden Eagle risk to lead and anticoagulant rodenticide exposure: A review

USGS Publications Warehouse

Herring, Garth; Eagles-Smith, Collin A.; Buck, Jeremy A.

2017-01-01

Contaminant exposure is among the many threats to Golden Eagle (Aquila chrysaetos) populations throughout North America, particularly lead poisoning and anticoagulant rodenticides (AR). These threats may act in concert with others (e.g., lead poisoning and trauma associated with striking objects) to exacerbate risk. Golden Eagles are skilled hunters but also exploit scavenging opportunities, making them particularly susceptible to contaminant exposure from ingesting tissues of poisoned or shot animals. Lead poisoning has long been recognized as an important source of mortality for Golden Eagles throughout North America. More recently, ARs have been associated with both sublethal and lethal effects in raptor species worldwide. In this review, we examine the current state of knowledge for lead and AR exposure in Golden Eagles, drawing from the broader raptor contaminant ecology literature. We examine lead and AR sources within Golden Eagle habitats, exposure routes and toxicity, effects on individuals and populations, synergistic effects, and data and information needs. Continued research addressing data needs and information gaps will help with Golden Eagle conservation planning.

HYGIENE-AND FOOD-RELATED BEHAVIORS ASSOCIATED WITH BLOOD LEAD LEVELS OF YOUNG CHILDREN FROM LEAD-CONTAMINATED HOMES

EPA Science Inventory

Exposures associated with blood lead levels greater than 40 ug/dl in young children who live in lead-contaminated homes have been well documented. As the action level for lead is reduced, activities that contribute to lower levels of lead exposure must be identified. A child's ea...

Exposure assessment of organochlorine pesticides, arsenic, and lead in children from the major agricultural areas in Sonora, Mexico.

PubMed

Meza-Montenegro, Maria M; Valenzuela-Quintanar, Ana I; Balderas-Cortés, José J; Yañez-Estrada, Leticia; Gutiérrez-Coronado, Maria L; Cuevas-Robles, Alberto; Gandolfi, A Jay

2013-04-01

There is a lack of information of exposure to organochlorine pesticides (OCP) and some metals, such as lead (Pb) and arsenic (As), both of which were used as arsenicals pesticides, in children living in the major agricultural areas of Mexico. The objective of this study was to assess the exposure of children to different OCP, As, and Pb in the Yaqui and Mayo valleys of Sonora to generate population baseline levels of these toxins. A cross-sectional study was undertaken in 165 children (age 6-12 years old) from 10 communities from both valleys during 2009. Blood samples were analyzed for OCP and Pb and first morning void urine for inorganic As (InAs). All of the blood samples had detectable levels of dichlorodiphenyltrichloroethylene (p,p'-DDE) ranging from 0.25 to 10.3 μg/L. However lindane, dichlorodiphenyltrichloroethane (p,p'-DDT), aldrin, and endosulfan were detected in far less of the population (36.4, 23.6, 9.1, and 3 %, respectively). Methoxychlor and endrin were not found in any sample. The average value of Pb in this population was 3.2 μg Pb/dL (range 0.17-9.0) with 8.5 % of the samples having levels <5.0 μg Pb/dL. Urinary As levels ranged from 5.4 to 199 μg As/L with an average value of 31.0 μg As/L. Levels > 50 μg/L were observed in 12.7 % of the samples. Our results show that is important to start a risk-reduction program to decrease exposure to these toxins in Mexican communities. In addition, the results can be used to establish the baseline levels of exposure to these toxins in this agricultural region and may be used as a reference point for regulatory agencies.

Exposure Assessment of Organochlorine Pesticides, Arsenic, and Lead in Children From the Major Agricultural Areas in Sonora, Mexico

PubMed Central

Valenzuela-Quintanar, Ana I.; Balderas-Cortés, José J.; Yañez-Estrada, Leticia; Gutiérrez-Coronado, Maria L.; Cuevas-Robles, Alberto; Gandolfi, A. Jay

2014-01-01

There is a lack of information of exposure to organochlorine pesticides (OCP) and some metals, such as lead (Pb) and arsenic (As), both of which were used as arsenicals pesticides, in children living in the major agricultural areas of Mexico. The objective of this study was to assess the exposure of children to different OCP, As, and Pb in the Yaqui and Mayo valleys of Sonora to generate population baseline levels of these toxins. A cross-sectional study was undertaken in 165 children (age 6–12 years old) from 10 communities from both valleys during 2009. Blood samples were analyzed for OCP and Pb and first morning void urine for inorganic As (InAs). All of the blood samples had detectable levels of dichlorodiphenyltrichloroethylene (p,p′-DDE) ranging from 0.25 to 10.3 μg/L. However lindane, dichlorodiphenyltrichloroethane (p,p′-DDT), aldrin, and endosulfan were detected in far less of the population (36.4, 23.6, 9.1, and 3 %, respectively). Methoxychlor and endrin were not found in any sample. The average value of Pb in this population was 3.2 μg Pb/dL (range 0.17–9.0) with 8.5 % of the samples having levels <5.0 μg Pb/dL. Urinary As levels ranged from 5.4 to 199 μg As/L with an average value of 31.0 μg As/L. Levels > 50 μg/L were observed in 12.7 % of the samples. Our results show that is important to start a risk-reduction program to decrease exposure to these toxins in Mexican communities. In addition, the results can be used to establish the baseline levels of exposure to these toxins in this agricultural region and may be used as a reference point for regulatory agencies. PMID:23254566

Bisphenol A down-regulates rate-limiting Cyp11a1 to acutely inhibit steroidogenesis in cultured mouse antral follicles.

PubMed

Peretz, Jackye; Flaws, Jodi A

2013-09-01

Bisphenol A (BPA) is the backbone of polycarbonate plastic products and the epoxy resin lining of aluminum cans. Previous studies have shown that exposure to BPA decreases sex steroid hormone production in mouse antral follicles. The current study tests the hypothesis that BPA first decreases the expression levels of the steroidogenic enzyme cytochrome P450 side-chain cleavage (Cyp11a1) and steroidogenic acute regulatory protein (StAR) in mouse antral follicles, leading to a decrease in sex steroid hormone production in vitro. Further, the current study tests the hypothesis that these effects are acute and reversible after removal of BPA. Exposure to BPA (10μg/mL and 100μg/mL) significantly decreased expression of Cyp11a1 and StAR beginning at 18h and 72h, respectively, compared to controls. Exposure to BPA (10μg/mL and 100μg/mL) significantly decreased progesterone levels beginning at 24h and decreased androstenedione, testosterone, and estradiol levels at 72h and 96h compared to controls. Further, after removing BPA from the culture media at 20h, expression of Cyp11a1 and progesterone levels were restored to control levels by 48h and 72h, respectively. Additionally, expression of StAR and levels of androstenedione, testosterone, and estradiol never decreased compared to controls. These data suggest that BPA acutely decreases expression of Cyp11a1 as early as 18h and this reduction in Cyp11a1 may lead to a decrease in progesterone production by 24h, followed by a decrease in androstenedione, testosterone, and estradiol production and expression of StAR at 72h. Therefore, BPA exposure likely targets Cyp11a1 and steroidogenesis, but these effects are reversible with removal of BPA exposure. Copyright © 2013 Elsevier Inc. All rights reserved.

A Case Study of Environmental Injustice: The Failure in Flint

PubMed Central

Campbell, Carla; Greenberg, Rachael; Mankikar, Deepa; Ross, Ronald D.

2016-01-01

The failure by the city of Flint, Michigan to properly treat its municipal water system after a change in the source of water, has resulted in elevated lead levels in the city’s water and an increase in city children’s blood lead levels. Lead exposure in young children can lead to decrements in intelligence, development, behavior, attention and other neurological functions. This lack of ability to provide safe drinking water represents a failure to protect the public’s health at various governmental levels. This article describes how the tragedy happened, how low-income and minority populations are at particularly high risk for lead exposure and environmental injustice, and ways that we can move forward to prevent childhood lead exposure and lead poisoning, as well as prevent future Flint-like exposure events from occurring. Control of the manufacture and use of toxic chemicals to prevent adverse exposure to these substances is also discussed. Environmental injustice occurred throughout the Flint water contamination incident and there are lessons we can all learn from this debacle to move forward in promoting environmental justice. PMID:27690065

A Case Study of Environmental Injustice: The Failure in Flint.

PubMed

Campbell, Carla; Greenberg, Rachael; Mankikar, Deepa; Ross, Ronald D

2016-09-27

The failure by the city of Flint, Michigan to properly treat its municipal water system after a change in the source of water, has resulted in elevated lead levels in the city's water and an increase in city children's blood lead levels. Lead exposure in young children can lead to decrements in intelligence, development, behavior, attention and other neurological functions. This lack of ability to provide safe drinking water represents a failure to protect the public's health at various governmental levels. This article describes how the tragedy happened, how low-income and minority populations are at particularly high risk for lead exposure and environmental injustice, and ways that we can move forward to prevent childhood lead exposure and lead poisoning, as well as prevent future Flint-like exposure events from occurring. Control of the manufacture and use of toxic chemicals to prevent adverse exposure to these substances is also discussed. Environmental injustice occurred throughout the Flint water contamination incident and there are lessons we can all learn from this debacle to move forward in promoting environmental justice.

Lead in school drinking water: Canada can and should address this important ongoing exposure source.

PubMed

Barn, Prabjit; Kosatsky, Tom

2011-01-01

Reducing all preventable lead exposures in children should be a public health priority given that blood lead levels in children that were once considered "safe" have since been associated with important neuro-developmental deficits. Limited Canadian data indicate that school drinking water can be an important component of children's overall exposure to lead. Outside of Ontario, however, Canadian schools are not required to test for lead in water; in most of Canada, school testing is case by case, typically initiated by parental concerns. Provinces and territories are encouraged to follow Ontario's example by instituting a routine school water lead testing program in order to identify facilities where action can result in a decrease in students' exposure to lead. Testing and remediation frameworks developed by the US Environmental Protection Agency, Health Canada, and the province of Ontario provide direction to school boards and local and provincial/territorial health authorities.

Research and Industrial Application of a Process for Direct Reduction of Molten High-Lead Smelting Slag

NASA Astrophysics Data System (ADS)

Li, Weifeng; Zhan, Jing; Fan, Yanqing; Wei, Chang; Zhang, Chuanfu; Hwang, Jiann-Yang

2017-04-01

A pyrometallurgical process for the direct reduction of molten high-lead smelting slag obtained by the Shuikoushan (SKS) method was reported in this article using solid anthracite as the fuel and reductant. The chemical composition, the lead phase composition, and the physical properties of the molten high-lead slag were examined. The effects of the process parameters on the recovery rate of valued metals were investigated in the laboratory. According to the experimental results, a new efficient bottom blow reduction furnace was employed in the pilot-scale test for high-lead slag reduction. The results showed the average recovery rate of lead was more than 96.0% with lower Pb and high Zn content of the reducing slag under the condition of reduction temperature 1100-1200°C, coal ratio 5.5-7.5%, reduction time 90-150 min, CaO/SiO2 ratio 0.35-0.45, and FeO/SiO2 ratio 1.4-1.55. Moreover, nearly 250 kg of standard coal per ton of crude Pb output was reduced compared with the blast furnace reduction process.

The effect of three different (-135°C) whole body cryotherapy exposure durations on elite rugby league players.

PubMed

Selfe, James; Alexander, Jill; Costello, Joseph T; May, Karen; Garratt, Nigel; Atkins, Stephen; Dillon, Stephanie; Hurst, Howard; Davison, Matthew; Przybyla, Daria; Coley, Andrew; Bitcon, Mark; Littler, Greg; Richards, Jim

2014-01-01

Whole body cryotherapy (WBC) is the therapeutic application of extreme cold air for a short duration. Minimal evidence is available for determining optimal exposure time. To explore whether the length of WBC exposure induces differential changes in inflammatory markers, tissue oxygenation, skin and core temperature, thermal sensation and comfort. This study was a randomised cross over design with participants acting as their own control. Fourteen male professional first team super league rugby players were exposed to 1, 2, and 3 minutes of WBC at -135°C. Testing took place the day after a competitive league fixture, each exposure separated by seven days. No significant changes were found in the inflammatory cytokine interleukin six. Significant reductions (p<0.05) in deoxyhaemoglobin for gastrocnemius and vastus lateralis were found. In vastus lateralis significant reductions (p<0.05) in oxyhaemoglobin and tissue oxygenation index (p<0.05) were demonstrated. Significant reductions (p<0.05) in skin temperature were recorded. No significant changes were recorded in core temperature. Significant reductions (p<0.05) in thermal sensation and comfort were recorded. Three brief exposures to WBC separated by 1 week are not sufficient to induce physiological changes in IL-6 or core temperature. There are however significant changes in tissue oxyhaemoglobin, deoxyhaemoglobin, tissue oxygenation index, skin temperature and thermal sensation. We conclude that a 2 minute WBC exposure was the optimum exposure length at temperatures of -135°C and could be applied as the basis for future studies.

Role of orthophosphate as a corrosion inhibitor in chloraminated solutions containing tetravalent lead corrosion product PbO2.

PubMed

Ng, Ding-Quan; Strathmann, Timothy J; Lin, Yi-Pin

2012-10-16

Addition of orthophosphate has been commonly employed to suppress lead levels in drinking water. Its detailed mechanism and time required for it to become effective, however, have not been fully elucidated. In this study, we investigated the mechanistic role of orthophosphate as a corrosion inhibitor in controlling lead release from tetravalent lead corrosion product PbO(2) in chloraminated solutions, a system representing distribution networks experiencing disinfectant changeover from free chlorine to monochloramine. In all experiments with orthophosphate addition of at least 1 mg/L as P, peaking of soluble Pb(II) concentration within the first 24 h was observed before lead concentrations decreased and stabilized at levels lower than 15 μg/L. The variation of soluble Pb(II) concentration could be attributed to the dynamics between the rate of PbO(2) reductive dissolution, primarily induced by monochloramine decomposition, and that of chloropyromorphite (Pb(5)(PO(4))(3)Cl) precipitation, which did not occur until a critical supersaturation ratio of about 2.36 was reached in the solution. Our findings provide insights to how orthophosphate reduces lead levels under drinking water conditions and highlight the potential risk of short-term elevated lead concentrations. Intensive monitoring following the disinfectant changeover may be required to determine the overall lead exposure when using orthophosphate as a corrosion inhibitor.

UV-induced inhibition of adipokine production in subcutaneous fat aggravates dermal matrix degradation in human skin.

PubMed

Kim, Eun Ju; Kim, Yeon Kyung; Kim, Min-Kyoung; Kim, Sungsoo; Kim, Jin Yong; Lee, Dong Hun; Chung, Jin Ho

2016-05-10

Ultraviolet (UV) exposure to the human skin reduces triglycerides contents and lipid synthesis in the subcutaneous (SC) fat. Because adiponectin and leptin are the most abundant adipokines from the SC fat, we aim to investigate how they interact with UV exposure and skin aging. The expressions of adiponectin and leptin were significantly decreased in SC fat of sun-exposed forearm skin, in comparison with that of sun-protected buttock skin of the same elderly individuals, indicating that chronic UV exposure decreases both adipokines. Acute UV irradiation also decreased the expressions of adiponectin and leptin in SC fat. The expressions of adiponectin receptor 1/2 and leptin receptor were significantly decreased in the dermis as well as in SC fat. Moreover, while exogenous adiponectin and leptin administration prevented UV- and TNF-α induced matrix metalloproteinase (MMP)-1 expression, they also increased UV- and TNF-α induced reduction of type 1 procollagen production. Silencing of adiponectin, leptin or their receptors led to an increased MMP-1 and a decreased type 1 procollagen expression, which was reversed by treatment with recombinant human adiponectin or leptin. In conclusion, UV exposure decreases the expression of adiponectin and leptin, leading to the exacerbation of photoaging by stimulating MMP-1 expression and inhibiting procollagen synthesis.

Delayed Hippocampal Effects From a Single Exposure of Prepubertal Guinea Pigs to sub-lethal dose of Chlorpyrifos: A Magnetic Resonance Imaging and Spectroscopy Study

PubMed Central

Mullins, Roger J.; Xu, Su; Pereira, Edna F.R.; Mamczarz, Jacek; Albuquerque, Edson X.; Gullapalli, Rao P.

2013-01-01

This study was designed to test the hypothesis that in vivo Magnetic Resonance Imaging (MRI) and Spectroscopy (MRS) can detect in adulthood the neurotoxic effects of a single exposure of prepubertal guinea pigs to the organophosphorus pesticide chlorpyrifos. Twelve female guinea pigs were given either a single dose of chlorpyrifos (0.6xLD50 or 300 mg/kg, sc) or peanut oil (vehicle; 0.5 ml/kg, sc) at 35–40 days of age. One year after the exposure, the animals were tested in the Morris water maze. Three days after the end of the behavioral testing, the metabolic and structural integrity of the brain of the animals was examined by means of MRI/MRS. In the Morris water maze, the chlorpyrifos-exposed guinea pigs showed significant memory deficit. Although no significant anatomical differences were found between the chlorpyrifos-exposed guinea pigs and the control animals by in vivo MRI, the chlorpyrifos-exposed animals showed significant decreases in hippocampal myo-inositol concentration using MRS. The present results indicate that a single sub-lethal exposure of prepubertal guinea pigs to the organophosphorus pesticide chlorpyrifos can lead to long-term memory deficits that are accompanied by significant reductions in the levels of hippocampal myo-inositol. PMID:23411083

Occupational exposures to leaded and unleaded gasoline engine emissions and lung cancer risk.

PubMed

Xu, Mengting; Siemiatycki, Jack; Lavoué, Jérôme; Pasquet, Romain; Pintos, Javier; Rousseau, Marie-Claude; Richardson, Lesley; Ho, Vikki

2018-04-01

To determine whether occupational exposure to gasoline engine emissions (GEE) increased the risk of lung cancer and more specifically whether leaded or unleaded GEE increased the risk. Two population-based case-control studies were conducted in Montreal, Canada. The first was conducted in the early 1980s and included many types of cancer including lung cancer. The second was conducted in the late 1990s and focused on lung cancer. Population controls were used in both studies. Altogether, there were 1595 cases and 1432 population controls. A comprehensive expert-based exposure assessment procedure was implemented and exposure was assessed for 294 agents, including unleaded GEE, leaded GEE and diesel engine emissions (DEE). Logistic regression analyses were conducted to estimate ORs between various metrics of GEE exposure and lung cancer, adjusting for smoking, DEE and other potential confounders. About half of all controls were occupationally exposed to GEE. Irrespective of the metrics of exposure (any exposure, duration of exposure and cumulative exposure) and the type of lung cancer, and the covariates included in models, none of the point estimates of the ORs between occupational exposure to leaded or unleaded GEE and lung cancer were above 1.0. Pooling two studies, the OR for any exposure to leaded GEE was 0.82 (0.68-1.00). Our results do not support the hypothesis that occupational exposure to GEE increases the risk of lung cancer. © 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.

Effects of lead exposure before pregnancy and dietary calcium during pregnancy on fetal development and lead accumulation.

PubMed Central

Han, S; Pfizenmaier, D H; Garcia, E; Eguez, M L; Ling, M; Kemp, F W; Bogden, J D

2000-01-01

Millions of women of child-bearing age have substantial bone lead stores due to lead exposure as children. Dietary calcium ingested simultaneously with lead exposure can reduce lead absorption and accumulation. However, the effects of dietary calcium on previously accumulated maternal lead stores and transfer to the fetus have not been investigated. We studied the effects of lead exposure of female rats at an early age on fetal development during a subsequent pregnancy. We gave 5-week-old female Sprague-Dawley rats lead as the acetate in their drinking water for 5 weeks; controls received equimolar sodium acetate. This was followed by a 1-month period without lead exposure before mating. We randomly assigned pregnant rats (n = 39) to diets with a deficient (0.1%) or normal (0.5%) calcium content during pregnancy. A total of 345 pups were delivered alive. Lead-exposed dams and their pups had significantly higher blood lead concentrations than controls, but the concentrations were in the range of those found in many pregnant women. Pups born to dams fed the calcium-deficient diet during pregnancy had higher blood and organ lead concentrations than pups born to dams fed the 0. 5% calcium diet. Pups born to lead-exposed dams had significantly (p<0.0001) lower mean birth weights and birth lengths than controls. There were significant inverse univariate associations between dam or pup organ lead concentrations and birth weight or length. The 0.5% calcium diet did not increase in utero growth. Stepwise regression analysis demonstrated that greater litter size and female sex were significantly associated with reduced pup birth weight and length. However, lead exposure that ended well before pregnancy was significantly (p<0.0001) associated with reduced birth weight and length, even after litter size, pup sex, and dam weight gain during pregnancy were included in the regression analysis. The data demonstrate that an increase in dietary calcium during pregnancy can reduce fetal lead accumulation but cannot prevent lead-induced decreases in birth weight and length. The results provide evidence that dietary nutrients can influence the transfer of toxins to the fetus during pregnancy. If these results are applicable to women, an increase in diet calcium during pregnancy could reduce the transfer of lead from prepregnancy maternal exposures to the fetus. Images Figure 3 Figure 4 Figure 1 Figure 2 PMID:10856026

Strut Shaping of 34m Beam Waveguide Antenna for Reductions in Near-Field RF and Noise Temeperature

NASA Technical Reports Server (NTRS)

Khayatian, Behrouz; Hoppe, Daniel J.; Britcliffe, Michael J.; Gama, Eric

2012-01-01

Struts shaping of the NASA's Deep Space Network (DSN) 34m Beam Waveguide (BWG) antenna has been implemented to reduce near-field RF exposure while improving the antenna noise temperature. Strut shaping was achieved by introducing an RF shield that does not compromise the structural integrity of the existing structure. Reduction in the RF near-field exposure will compensate for the planned transmit power increase of the antenna from 20 kW to 80 kW while satisfying safety requirements for RF exposure. Antenna noise temperature was also improved by as much as 1.5 K for the low elevation angles and 0.5 K in other areas. Both reductions of RF near-field exposure and antenna noise temperature were verified through measurements and agree very well with calculated results.

Reducing Health Risks from Indoor Exposures in Rapidly Developing Urban China

PubMed Central

Zhang, Yinping; Mo, Jinhan

2013-01-01

Background: Over the past two decades there has been a large migration of China’s population from rural to urban regions. At the same time, residences in cities have changed in character from single-story or low-rise buildings to high-rise structures constructed and furnished with many synthetic materials. As a consequence, indoor exposures (to pollutants with outdoor and indoor sources) have changed significantly. Objectives: We briefly discuss the inferred impact that urbanization and modernization have had on indoor exposures and public health in China. We argue that growing adverse health costs associated with these changes are not inevitable, and we present steps that could be taken to reduce indoor exposures to harmful pollutants. Discussion: As documented by China’s Ministry of Health, there have been significant increases in morbidity and mortality among urban residents over the past 20 years. Evidence suggests that the population’s exposure to air pollutants has contributed to increases in lung cancer, cardiovascular disease, pulmonary disease, and birth defects. Whether a pollutant has an outdoor or an indoor source, most exposure to the pollutant occurs indoors. Going forward, indoor exposures can be reduced by limiting the ingress of outdoor pollutants (while providing adequate ventilation with clean air), minimizing indoor sources of pollutants, updating government policies related to indoor pollution, and addressing indoor air quality during a building’s initial design. Conclusions: Taking the suggested steps could lead to significant reductions in morbidity and mortality, greatly reducing the societal costs associated with pollutant derived ill health. PMID:23665813

Effects of the Irish smoking ban on respiratory health of bar workers and air quality in Dublin pubs.

PubMed

Goodman, Patrick; Agnew, Michelle; McCaffrey, Marie; Paul, Gillian; Clancy, Luke

2007-04-15

Environmental tobacco smoke (ETS) causes disease in nonsmokers. Workplace bans on smoking are interventions to reduce exposure to ETS to try to prevent harmful health effects. On March 29, 2004, the Irish government introduced the first national comprehensive legislation banning smoking in all workplaces, including bars and restaurants. This study examines the impact of this legislation on air quality in pubs and on respiratory health effects in bar workers in Dublin. Exposure study. Concentrations of particulate matter 2.5 microm or smaller (PM(2.5)) and particulate matter 10 microm or smaller (PM(10)) in 42 pubs were measured and compared before and after the ban. Benzene concentrations were also measured in 26 of the pubs. Health effects study. Eighty-one barmen volunteered to have full pulmonary function studies, exhaled breath carbon monoxide, and salivary cotinine levels performed before the ban and repeated 1 year after the ban. They also completed questionnaires on exposure to ETS and respiratory symptoms on both occasions. Exposure study. There was an 83% reduction in PM(2.5) and an 80.2% reduction in benzene concentration in the bars. Health effects study. There was a 79% reduction in exhaled breath carbon monoxide and an 81% reduction in salivary cotinine. There were statistically significant improvements in measured pulmonary function tests and significant reductions in self-reported symptoms and exposure levels in nonsmoking barmen volunteers after the ban. A total workplace smoking ban results in a significant reduction in air pollution in pubs and an improvement in respiratory health in barmen.

E-Waste Informal Recycling: An Emerging Source of Lead Exposure in South America

PubMed Central

Pascale, Antonio; Sosa, Adriana; Bares, Cristina; Battocletti, Alejandra; Moll, María José; Pose, Darío; Laborde, Amalia; González, Hugo; Feola, Gabriella

2016-01-01

BACKGROUND Primitive electronic waste (e-waste) recycling creates exposures to several hazardous substances including lead. In Uruguay, primitive recycling procedures are a significant source of lead exposure. OBJECTIVES The aim of this study was to examine lead exposure in blood lead levels (BLLs) in low-income children exposed to lead through burning cables. METHODS A sample of children and adolescents exposed to lead through burning cable activities were assessed at the Department of Toxicology in Montevideo, Uruguay, between 2010 and 2014. Soil lead levels of residences were taken shortly after their assessment. FINDINGS The final sample included 69 children and adolescents (mean age 7.89 years). More than 66% of participants had an additional source of lead exposure—manual gathering of metals—and <5% were exposed to lead through landfills or paint. Average BLLs at first consultation were 9.19 ug/dL and lower at the second measurement (5.86 μg/dL). Data from soil lead levels ranged from 650 to 19,000 mg of lead/kg of soil. The interventions conducted after the assessment included family education in the clinic and at home, indoor and outdoor remediation. We found a decrease in BLLs of 6.96 μg/dL. Older children had lower BLLs (r = −0.24; P =0.05). Statistical analyses also showed that children living in areas with higher soil lead levels had significantly higher BLLs (r = 0.50; P < 0.01). Additionally, we found greater BLLs from burning cable activities when children had been exposed to lead-based paint (r = 0.23; P < 0.1). CONCLUSION Among children exposed to e-waste recycling, the most common additional source of lead exposure was the manual gathering of metals. The average BLL among children and adolescents in this study is higher than the BLLs currently suggested in medical intervention. Future research should focus on exploring effective interventions to reduce lead exposure among this vulnerable group. PMID:27325077

Urban UV environment in a sub-tropical megacity - A measurement and modelling study

NASA Astrophysics Data System (ADS)

Wai, Ka-Ming; Yu, Peter K. N.; Chan, Pok-Man

The variations of solar total UV (UVA + UVB) exposure rates in a megacity featured with high-rise buildings during summer months were measured and relevant model predictions were evaluated. The maximum pedestrian-level total solar UV exposure rate was less than the un-obstructed exposure rate at any time, attributing to the prevailing reduction in the diffuse solar radiation due to the obstruction effects of distant buildings. Comparing with the measurements, our coupled model well captured the spatial and temporal variations of the reduction of UV exposure rates. By measurements, large reduction in the solar total UV exposure rate down to 12% of un-obstructed exposure rate due to the building obstruction effects was found, agreeing with our previous simulation results and results from an Australian megacity. On the other hand, building reflection from reflective curtain walls could reach 23% of the un-obstructed solar total UV exposure rate at the ground level. This implied improper building design creating additional harmful effects of solar UV radiation on the environment. The coupled model was also applied to predict the urban UV exposure rates during a tropical-cyclone induced aerosol episode. A well-evaluated urban solar UV model is an important tool for sustainable urban design.

Influence of different anoxic time exposures on active biomass, protozoa and filamentous bacteria in activated sludge.

PubMed

Rodriguez-Perez, S; Fermoso, F G; Arnaiz, C

Medium-sized wastewater treatment plants are considered too small to implement anaerobic digestion technologies and too large for extensive treatments. A promising option as a sewage sludge reduction method is the inclusion of anoxic time exposures. In the present study, three different anoxic time exposures of 12, 6 and 4 hours have been studied to reduce sewage sludge production. The best anoxic time exposure was observed under anoxic/oxic cycles of 6 hours, which reduced 29.63% of the biomass production compared with the oxic control conditions. The sludge under different anoxic time exposures, even with a lower active biomass concentration than the oxic control conditions, showed a much higher metabolic activity than the oxic control conditions. Microbiological results suggested that both protozoa density and abundance of filamentous bacteria decrease under anoxic time exposures compared to oxic control conditions. The anoxic time exposures 6/6 showed the highest reduction in both protozoa density, 37.5%, and abundance of filamentous bacteria, 41.1%, in comparison to the oxic control conditions. The groups of crawling ciliates, carnivorous ciliates and filamentous bacteria were highly influenced by the anoxic time exposures. Protozoa density and abundance of filamentous bacteria have been shown as promising bioindicators of biomass production reduction.

End-stage renal disease after occupational lead exposure: 20 years of follow-up.

PubMed

Evans, Marie; Discacciati, Andrea; Quershi, Abdul Rashid; Åkesson, Agneta; Elinder, Carl-Gustaf

2017-06-01

Whether low-level exposure to lead may give rise to chronic kidney disease or end-stage renal disease (ESRD) is debated. In this study, we aimed to specifically investigate if low-level occupational exposure to lead was associated with increased incidence of ESRD. The incidence of starting renal replacement therapy as a result of ESRD was examined in a cohort of10 303 lead-workers who had controlled blood lead concentrations due to a compulsory occupational health surveillance programme in Sweden during the time period 1977-1990. The ESRD incidence (obtained through register-linkage) among the lead-exposed workers was compared with the age, sex and calendar period-adjusted expected incidence based on data from the Swedish renal registry. Dose-response association was evaluated in external (general population) and internal (within the occupational cohort) comparisons by highest achieved blood lead level. There were 30 (0.29%) individuals in the cohort who developed ESRD during the median follow-up period of 26.3 years. The standardised incidence ratio (SIR) for ESRD incidence was 0.79 (95% CI 0.54 to 1.13). Among those who achieved the highest blood lead (>41.4 µg/dL), the SIR was 1.01 (0.44 to 1.99). There was no evidence of a dose-response relationship between the maximum achieved blood lead or the cumulative blood lead exposure and ESRD in external or internal comparisons. This study of workers with documented occupational lead exposures followed for 20 years shows no statistically significant association between lead exposure (following the current occupational recommendations for Sweden) and ESRD. 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/.

Childhood Lead Exposure After the Phaseout of Leaded Gasoline: An Ecological Study of School-Age Children in Kampala, Uganda

PubMed Central

Graber, Lauren K.; Asher, Daniel; Anandaraja, Natasha; Bopp, Richard F.; Merrill, Karen; Cullen, Mark R.; Luboga, Samuel; Trasande, Leonardo

2010-01-01

Background Tetraethyl lead was phased out of gasoline in Uganda in 2005. Recent mitigation of an important source of lead exposure suggests examination and re-evaluation of the prevalence of childhood lead poisoning in this country. Ongoing concerns persist about exposure from the Kiteezi landfill in Kampala, the country’s capital. Objectives We determined blood lead distributions among Kampala schoolchildren and identified risk factors for elevated blood lead levels (EBLLs; ≥ 10 μg/dL). Analytical approach Using a stratified, cross-sectional design, we obtained blood samples, questionnaire data, and soil and dust samples from the homes and schools of 163 4- to 8-year-old children representing communities with different risks of exposure. Results The mean blood lead level (BLL) was 7.15 μg/dL; 20.5% of the children were found to have EBLL. Multivariable analysis found participants whose families owned fewer household items, ate canned food, or used the community water supply as their primary water source to have higher BLLs and likelihood of EBLLs. Distance < 0.5 mi from the landfill was the factor most strongly associated with increments in BLL (5.51 μg/dL, p < 0.0001) and likelihood of EBLL (OR = 4.71, p = 0.0093). Dust/soil lead was not significantly predictive of BLL/EBLL. Conclusions Lead poisoning remains highly prevalent among school-age children in Kampala. Confirmatory studies are needed, but further efforts are indicated to limit lead exposure from the landfill, whether through water contamination or through another mechanism. Although African nations are to be lauded for the removal of lead from gasoline, this study serves as a reminder that other sources of exposure to this potent neurotoxicant merit ongoing attention. PMID:20194080

Occupational lead exposure aboard a tall ship.

PubMed

Landrigan, P J; Straub, W E

1985-01-01

To evaluate occupational exposures to lead in shipfitters cutting and riveting lead-painted iron plates aboard an iron-hulled sailing vessel, we conducted an environmental and medical survey. Lead exposures in seven personal (breathing zone) air samples ranged from 108 to 500 micrograms/m3 (mean 257 micrograms/m3); all were above the Occupational Safety and Health Administration (OSHA) standard of 50 micrograms/m3. In two short-term air samples obtained while exhaust ventilation was temporarily disconnected, mean lead exposure rose to 547 micrograms/m3. Blood lead levels in ten shipfitters ranged from 25 to 53 micrograms/dl (mean, 37.8 micrograms/dl); levels in three of these workers exceeded the upper normal limit of 40 micrograms/dl. Blood lead levels in shipfitters were significantly higher than in other shipyard workers (mean 10.0 micrograms/dl; p less than 0.001). Smoking shipfitters (mean, 47 micrograms/dl) had significantly higher lead levels than nonsmokers (mean, 32 micrograms/dl; p = 0.03). Lead levels in shipfitters who wore respirators were not lower than in those who wore no protective gear (p = 0.68). Four shipfitters had erythrocyte protoporphyrin (EP) concentrations above the adult upper normal limit of 50 micrograms/dl. A close correlation was found between blood lead and EP levels (r = 0.70). Prevalence of lead-related symptoms was no higher in shipfitters than in other workers. No cases of symptomatic lead poisoning were noted. These data indicate that serious occupational exposure to lead can occur in a relatively small boatyard.

Olfactory recognition memory is disrupted in young mice with chronic low-level lead exposure.

PubMed

Flores-Montoya, Mayra Gisel; Alvarez, Juan Manuel; Sobin, Christina

2015-07-02

Chronic developmental lead exposure yielding very low blood lead burden is an unresolved child public health problem. Few studies have attempted to model neurobehavioral changes in young animals following very low level exposure, and studies are needed to identify tests that are sensitive to the neurobehavioral changes that may occur. Mechanisms of action are not yet known however results have suggested that hippocampus/dentate gyrus may be uniquely vulnerable to early chronic low-level lead exposure. This study examined the sensitivity of a novel odor recognition task to differences in pre-adolescent C57BL/6J mice chronically exposed from birth to PND 28, to 0 ppm (control), 30 ppm (low-dose), or 330 ppm (higher-dose) lead acetate (N=33). Blood lead levels (BLLs) determined by ICP-MS ranged from 0.02 to 20.31 μg/dL. Generalized linear mixed model analyses with litter as a random effect showed a significant interaction of BLL×sex. As BLLs increased olfactory recognition memory decreased in males. Among females, non-linear effects were observed at lower but not higher levels of lead exposure. The novel odor detection task is sensitive to effects associated with early chronic low-level lead exposure in young C57BL/6J mice. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Oxidative Stress, Bone Marrow Failure, and Genome Instability in Hematopoietic Stem Cells

PubMed Central

Richardson, Christine; Yan, Shan; Vestal, C. Greer

2015-01-01

Reactive oxygen species (ROS) can be generated by defective endogenous reduction of oxygen by cellular enzymes or in the mitochondrial respiratory pathway, as well as by exogenous exposure to UV or environmental damaging agents. Regulation of intracellular ROS levels is critical since increases above normal concentrations lead to oxidative stress and DNA damage. A growing body of evidence indicates that the inability to regulate high levels of ROS leading to alteration of cellular homeostasis or defective repair of ROS-induced damage lies at the root of diseases characterized by both neurodegeneration and bone marrow failure as well as cancer. That these diseases may be reflective of the dynamic ability of cells to respond to ROS through developmental stages and aging lies in the similarities between phenotypes at the cellular level. This review summarizes work linking the ability to regulate intracellular ROS to the hematopoietic stem cell phenotype, aging, and disease. PMID:25622253

Is cutaneous malignant melanoma associated with the use of antibacterial soaps?

PubMed

Arbesman, H

1999-07-01

Since 1960, the incidence of melanoma has increased dramatically in Caucasians worldwide, and during the past decade has risen at a rate of 6% a year in the USA. A hypothesis regarding this increased incidence suggests that the prevalent use of antibacterial soaps that contain photosensitizing compounds may be a risk factor for the development of cutaneous malignant melanoma. These antibacterial soaps were introduced in the 1960s and compounds with photosensitizing properties are still present in various soaps throughout the industrialized world. The use of these antibacterial soaps, in combination with sun exposure, leads to free radical production in the skin. These free radicals are hypothesized to cause damage to melanocytes, leading to the development of melanoma. Various epidemiological findings regarding melanoma are consistent with this hypothesis. A significant reduction in the number of new cases of melanoma could be achieved if this hypothesis is correct.

Validation of a spectrophotometric method for quantification of carboxyhemoglobin.

PubMed

Luchini, Paulo D; Leyton, Jaime F; Strombech, Maria de Lourdes C; Ponce, Julio C; Jesus, Maria das Graças S; Leyton, Vilma

2009-10-01

The measurement of carboxyhemoglobin (COHb) levels in blood is a valuable procedure to confirm exposure to carbon monoxide (CO) either for forensic or occupational matters. A previously described method using spectrophotometric readings at 420 and 432 nm after reduction of oxyhemoglobin (O(2)Hb) and methemoglobin with sodium hydrosulfite solution leads to an exponential curve. This curve, used with pre-established factors, serves well for lower concentrations (1-7%) or for high concentrations (> 20%) but very rarely for both. The authors have observed that small variations on the previously described factors F1, F2, and F3, obtained from readings for 100% COHb and 100% O(2)Hb, turn into significant changes in COHb% results and propose that these factors should be determined every time COHb is measured by reading CO and O(2) saturated samples. This practice leads to an increase in accuracy and precision.

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

USGS Publications Warehouse

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

1996-01-01

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

Feasibility of a portable X-ray fluorescence device for bone lead measurements of condor bones.

PubMed

Specht, Aaron J; Parish, Chris N; Wallens, Emma K; Watson, Rick T; Nie, Linda H; Weisskopf, Marc G

2018-02-15

Lead based ammunition is a primary source of lead exposure, especially for scavenging wildlife. Lead poisoning remains the leading cause of diagnosed death for the critically endangered California condors, which are annually monitored via blood tests for lead exposure. The results of these tests are helpful in determining recent exposure in condors and in defining the potential for exposure to other species including humans. Since condors are victim to acute and chronic lead exposure, being able to measure both would lend valuable information on the rates of exposure and accumulation through time. A commercial portable X-ray fluorescence (XRF) device has been optimized to measure bone lead in vivo in humans, but this device could also be valuable for field measurements of bone lead in avian species. In this study, we performed measurements of bone Pb in excised, bare condor bones using inductively coupled plasma mass spectrometry (ICP-MS), a cadmium 109 (Cd-109) K-shell X-ray fluorescence (KXRF) system, and a portable XRF system. Both KXRF and portable XRF bone Pb measurement techniques demonstrated good correlations with ICP-MS results (r=0.93 and r=0.92 respectively), even with increasing skin thickness (r=0.86 between ICP-MS and portable XRF at 1.54mm of soft tissue). In conclusion, our results suggest that a portable XRF could be a useful option for measurement of bone Pb in avian species in the field. Copyright © 2017 Elsevier B.V. All rights reserved.

Quantitative assessment of human exposure to extended spectrum and AmpC β-lactamases bearing E. coli in lettuce attributable to irrigation water and subsequent horizontal gene transfer.

PubMed

Njage, P M K; Buys, E M

2017-01-02

The contribution of the fresh produce production environment to human exposure with bacteria bearing extended spectrum β-lactamases and AmpC β-lactamases (ESBL/AmpC) has not been reported. High prevalence of ESBLs/AmpC bearing E. coli as well as a high gene transfer efficiency of lettuce and irrigation water E. coli isolates was previously reported. This stochastic modeling was aimed at quantitatively assessing human exposure to ESBL/AmpC bearing E. coli through lettuce attributable to irrigation water and subsequent horizontal gene transfer. Modular process risk approach was used for the quantitative exposure assessment and models were constructed in Ms. Excel spreadsheet with farm to consumption chain accounted for by primary production, processing, retail and consumer storage. Probability distributions were utilised to take into account the variability of the exposure estimates. Exposure resulting from ESBL/AmpC positive E. coli and gene transfer was taken into account. Monte Carlo simulation was carried out using @Risk software followed by sensitivity and scenario analysis to assess most effective single or combinations of mitigation strategies for the ESBL/AmpC positive E. coli events from farm to fork. Three percent of South African lettuce consumers are exposed to lettuce contaminated with about 10 6.4 ±10 6.7 (95% CI: 10 5.1 -10 7 ) cfu of ESBL/AmpC positive E. coli per serving. The contribution of originally positive isolates and conjugative genetic transfer was 10 6 ±10 6.7 (95% CI: 10 5 -10 7 ) and 10 5.2 ±10 5.6 (95% CI: 10 3.9 -10 5.8 ) cfu per serving respectively. Proportion of ESBL/AmpC positive E. coli (Spearman's correlation coefficient (ρ)=0.85), conjugative gene transfer (ρ=0.05-0.14), washing in chlorine water (ρ=0.18), further rinsing (ρ=0.15), and prevalence of E. coli in irrigation water (ρ=0.16) had highest influence on consumer exposure. The most effective single methods in reducing consumer exposure were reduction in irrigation water microbial quality variation (87.4% reduction), storage period (49.9-87.4% reduction) and growth rate reduction by 75% (90% reduction). Reduction in growth rate together with storage time (92.1-99.4%) and reduction in storage time combined with E. coli concentration in irrigation water (95-96% reduction) were most effective combinations of mitigation measures. The high variation in exposure reflected the high irrigation water quality variation. The exposure levels may impose higher consumer risk than acceptable for irrigation water risk. E. coli contamination and growth related measures, as well as measures to reduce contamination with antimicrobial resistant E. coli from lettuce production environment are recommended. This exposure model could form a basis for the development of similar models assessing the impact of contaminated irrigation water and gene transfer in other microbial hazards, antimicrobial resistance types and fresh produce types. Copyright © 2016 Elsevier B.V. All rights reserved.

Quantitative health impact assessment of transport policies: two simulations related to speed limit reduction and traffic re-allocation in the Netherlands.

PubMed

Schram-Bijkerk, D; van Kempen, E; Knol, A B; Kruize, H; Staatsen, B; van Kamp, I

2009-10-01

Few quantitative health impact assessments (HIAs) of transport policies have been published so far and there is a lack of a common methodology for such assessments. To evaluate the usability of existing HIA methodology to quantify health effects of transport policies at the local level. Health impact of two simulated but realistic transport interventions - speed limit reduction and traffic re-allocation - was quantified by selecting traffic-related exposures and health endpoints, modelling of population exposure, selecting exposure-effect relations and estimating the number of local traffic-related cases and disease burden, expressed in disability-adjusted life-years (DALYs), before and after the intervention. Exposure information was difficult to retrieve because of the local scale of the interventions, and exposure-effect relations for subgroups and combined effects were missing. Given uncertainty in the outcomes originating from this kind of missing information, simulated changes in population health by two local traffic interventions were estimated to be small (<5%), except for the estimated reduction in DALYs by less traffic accidents (60%) due to speed limit reduction. Quantitative HIA of transport policies at a local scale is possible, provided that data on exposures, the exposed population and their baseline health status are available. The interpretation of the HIA information should be carried out in the context of the quality of input data and assumptions and uncertainties of the analysis.

DIETARY EXPOSURE OF CHILDREN LIVING IN LEAD-LADEN ENVIRONMENTS

EPA Science Inventory

Children are the most susceptible population to lead exposure because of three interacting factors: they have more opportunity for contact with lead sources due to their activities; lead absorption occurs more readily in a child as compared to an adult; and the child's developmen...

DIETARY EXPOSURE OF CHILDREN TO LEAD

EPA Science Inventory

Children are the most susceptible population to lead exposure because 1) they have more opportunity for contact with lead sources due to their activities, 2) lead adsorption occurs more readily in a child as compared to an adult, and 3) the child's development is more vulnerable ...

DIETARY EXPOSURE OF CHILDREN IN LEAD-LADEN ENVIRONMENTS

EPA Science Inventory

Children are the most susceptible population to lead exposure because of three interacting factors; they have more opportunity for contact with lead sources due to their activities, lead absorption occurs more readily in a child compared to an adult, and the child's development i...

Lead exposure among automobile radiator repair workers and their children in New York City.

PubMed

Nunez, C M; Klitzman, S; Goodman, A

1993-05-01

Despite a comprehensive Occupational Safety and Health Administration lead standard, exposure to lead continues in many industries. This paper describes a blood lead screening and education program for automobile radiator repair workers and their families in New York City. Results showed that 67% of automobile radiator repair workers (n = 62) in 89% of the shops tested (n = 24) had blood lead levels in excess of 25 micrograms/dl. The vast majority of workers had never been tested previously, and none had received health and safety training regarding occupational lead exposure. Although none of the workers' children's blood lead levels were in excess of then-current guidelines, several had levels which may be associated with subclinical toxicity and in excess of the revised Centers for Disease Control guidelines of 10 micrograms/dl. This project demonstrates that lead exposure in the automotive radiator repair industry continues to be widespread and that local health departments can assist in hazard identification and remediation.

Prenatal lead exposure and childhood blood pressure and kidney function.

PubMed

Skröder, Helena; Hawkesworth, Sophie; Moore, Sophie E; Wagatsuma, Yukiko; Kippler, Maria; Vahter, Marie

2016-11-01

Exposure to lead, a common environmental pollutant, is known to cause cardiovascular and nephrotoxic effects in adults. Potential effects of early-life lead exposure on these functions are, however, less well characterized. To assess blood pressure and kidney function in preschool-aged children in relation to prenatal lead exposure. This prospective study in rural Bangladesh measured children's systolic and diastolic blood pressure in triplicate at the follow-up at 4.5±0.11 years. Their kidney function was assessed by the estimated glomerular filtration rate (eGFR), calculated based on serum cystatin C concentrations, and by kidney volume, measured by sonography. Exposure to lead was assessed by concentrations in the mothers' blood (erythrocyte fraction; Ery-Pb) in gestational weeks (GW) 14 and 30, the effects of which were evaluated separately in multivariable-adjusted linear regression analyses. We found no associations between maternal exposure to lead [n~1500 for GW14 and 700 for GW30] and children's blood pressure or eGFR. However, we found an inverse association between late gestation lead and kidney volume, although the sample size was limited (n=117), but not with early gestation lead (n=573). An increase of 85µg/kg in Ery-Pb (median concentration at GW30) was associated with a 6.0cm 3 /m 2 decrease in kidney volume (=0.4SD; p=0.041). After stratifying on gender, there seemed to be a somewhat stronger association in girls. Prenatal lead exposure may cause long-lasting effects on the kidney. This warrants follow-up studies in older children, as well as additional studies in other populations. Copyright © 2016. Published by Elsevier Inc.

Children’s Lead Exposure: A Multimedia Modeling Analysis to Guide Public Health Decision-Making

PubMed Central

Xue, Jianping; Tornero-Velez, Rogelio; Brown, James

2017-01-01

Background: Drinking water and other sources for lead are the subject of public health concerns around the Flint, Michigan, drinking water and East Chicago, Indiana, lead in soil crises. In 2015, the U.S. Environmental Protection Agency (EPA)’s National Drinking Water Advisory Council (NDWAC) recommended establishment of a “health-based, household action level” for lead in drinking water based on children’s exposure. Objectives: The primary objective was to develop a coupled exposure–dose modeling approach that can be used to determine what drinking water lead concentrations keep children’s blood lead levels (BLLs) below specified values, considering exposures from water, soil, dust, food, and air. Related objectives were to evaluate the coupled model estimates using real-world blood lead data, to quantify relative contributions by the various media, and to identify key model inputs. Methods: A modeling approach using the EPA’s Stochastic Human Exposure and Dose Simulation (SHEDS)-Multimedia and Integrated Exposure Uptake and Biokinetic (IEUBK) models was developed using available data. This analysis for the U.S. population of young children probabilistically simulated multimedia exposures and estimated relative contributions of media to BLLs across all population percentiles for several age groups. Results: Modeled BLLs compared well with nationally representative BLLs (0–23% relative error). Analyses revealed relative importance of soil and dust ingestion exposure pathways and associated Pb intake rates; water ingestion was also a main pathway, especially for infants. Conclusions: This methodology advances scientific understanding of the relationship between lead concentrations in drinking water and BLLs in children. It can guide national health-based benchmarks for lead and related community public health decisions. https://doi.org/10.1289/EHP1605 PMID:28934096

Interaction between DRD2 and lead exposure on the cortical thickness of the frontal lobe in youth with attention-deficit/hyperactivity disorder.

PubMed

Kim, Johanna Inhyang; Kim, Jae-Won; Lee, Jong-Min; Yun, Hyuk Jin; Sohn, Chul-Ho; Shin, Min-Sup; Kim, Bongseog; Chae, Jonghee; Roh, Jaewoo; Kim, Bung-Nyun

2018-03-02

The dopamine receptor D2 receptor (DRD2) gene and lead exposure are both thought to contribute to the pathophysiology of attention-deficit/hyperactivity disorder (ADHD). ADHD is characterized by delay in brain maturation, most prominent in the prefrontal cortex (PFC). The D2 receptor is also mainly located in the PFC, and animal studies show that lead exposure affects the dopaminergic system of the frontal lobe, indicating an overlap in neural correlates of ADHD, DRD2, and lead exposure. We examined the interaction effects of DRD2 rs1800497 and lead exposure on the cortical thickness of the frontal lobe in patients with ADHD. A 1:1 age- and gender-matched sample of 75 participants with ADHD and 75 healthy participants was included in the analysis. The interaction effects of DRD2 and lead exposure on the cortical thickness of 12 regions of interest in the frontal lobe were examined by multivariable linear regression analyses. When we investigated the DRD2×lead effects in the ADHD and HC groups separately, significant DRD2×lead effects were found in the ADHD group, but not in the healthy control group in multiple ROIs of the frontal lobe. There was a significant negative correlation between the cortical thickness of the right superior frontal gyrus and inattention scores. The present findings demonstrated significant interaction effects of DRD2 and lead exposure on the cortical thickness of the frontal lobe in ADHD. Replication studies with larger sample sizes, using a prospective design, are warranted to confirm these findings. Copyright © 2017 Elsevier Inc. All rights reserved.

Nanosilica and Polyacrylate/Nanosilica: A Comparative Study of Acute Toxicity

PubMed Central

Niu, Ying-Mei; Zhu, Xiao-Li; Chang, Bing; Tong, Zhao-Hui; Cao, Wen; Qiao, Pei-Huan; Zhang, Lin-Yuan; Zhao, Jing; Song, Yu-Guo

2016-01-01

We compared the acute toxicity of nanosilica and polyacrylate/nanosilica instillation in Wistar rats (n = 60). Exposure to nanosilica and polyacrylate/nanosilica showed a 30% mortality rate. When compared with saline-treated rats, animals in both exposure groups exhibited a significant reduction of PO2 (P < 0.05) at both 24 and 72 hr. after exposure. Both exposure groups exhibited a significant reduction of neutrophils in arterial blood compared to saline controls (P < 0.05) 24 hr. after exposure. The levels of blood ALT and LDH in exposed groups were found to be significantly increased (P < 0.05) 24 hr. following exposure. The exposed groups exhibited various degrees of pleural effusion and pericardial effusion. Our findings indicated respiratory exposure to polyacrylate/nanosilica and nanosilica is likely to cause multiple organ toxicity. PMID:26981538

Lead Exposure Hazard Management Guide

DTIC Science & Technology

1993-12-01

that may pose chemical or physical problems . Make this section specific to your base or location. b. Exposure Routes. The potential routes of...Pregnant Mother ........ 14 nstallatio (Base) Lead Te xicity Investigations . Team Makeup and Duties ............ 15 Lead Toxicity Investigation...occurring in tradesmen who used lead in their occupations. The favorable physical and chemical properties of lead accounted for its extensive use. Lead can

Estimating the burden of disease attributable to lead exposure in South Africa in 2000.

PubMed

Norman, Rosana; Mathee, Angela; Barnes, Brendon; van der Merwe, Lize; Bradshaw, Debbie

2007-08-01

To estimate the burden of disease attributable to lead exposure in South Africa in 2000. World Health Organization comparative risk assessment (CRA) methodology was followed. Recent community studies were used to derive mean blood lead concentrations in adults and children in urban and rural areas. Population-attributable fractions were calculated and applied to revised burden of disease estimates for the relevant disease categories for South Africa in the year 2000. Monte Carlo simulation-modelling techniques were used for the uncertainty analysis. South Africa. Children under 5 and adults 30 years and older. Cardiovascular mortality and disability-adjusted life years (DALYs) in adults 30 years and older and mild mental disability DALYs in children under 5 years. Lead exposure was estimated to cause 1,428 deaths (95% uncertainty interval 1,086-1,772) or 0.27% (95% uncertainty interval: 0.21 - 0.34%) of all deaths in South Africa in 2000. Burden of disease attributed to lead exposure was dominated by mild mental disability in young children, accounting for 75% of the total 58,939 (95% uncertainty interval 55,413 - 62,500) attributable DALYs. Cardiovascular disease in adults accounted for the remainder of the burden. Even with the phasing out of leaded petrol, exposure to lead from its ongoing addition to paint, para-occupational exposure and its use in backyard 'cottage industries' will continue to be an important public health hazard in South Africa for decades. Young children, especially those from disadvantaged communities, remain particularly vulnerable to lead exposure and poisoning.

Lactobacillus plantarum CCFM8661 alleviates lead toxicity in mice.

PubMed

Tian, Fengwei; Zhai, Qixiao; Zhao, Jianxin; Liu, Xiaoming; Wang, Gang; Zhang, Hao; Zhang, Heping; Chen, Wei

2012-12-01

Lead causes a broad range of adverse effects in humans and animals. The objective was to evaluate the potency of lactobacilli to bind lead in vitro and the protective effects of a selected Lactobacillus plantarum CCFM8661 against lead-induced toxicity in mice. Nine strains of bacteria were used to investigate their binding abilities of lead in vitro, and L. plantarum CCFM8661 was selected for animal experiments because of its excellent lead binding capacity. Both living and dead L. plantarum CCFM8661 were used to treat 90 male Kunming mice during or after the exposure to 1 g/L lead acetate in drinking water. The results showed oral administration of both living and dead L. plantarum CCFM8661 offered a significant protective effect against lead toxicity by recovering blood δ-aminolevulinic acid dehydratase activity, decreasing the lead levels in blood and tissues, and preventing alterations in the levels of glutathione, glutathione peroxidase, malondialdehyde, superoxide dismutase, and reactive oxygen species caused by lead exposure. Moreover, L. plantarum CCFM8661 was more effective when administered consistently during the entire lead exposure, not after the exposure. Our results suggest that L. plantarum CCFM8661 has the potency to provide a dietary strategy against lead toxicity.

Neurotoxic effects and biomarkers of lead exposure: a review.

PubMed

Sanders, Talia; Liu, Yiming; Buchner, Virginia; Tchounwou, Paul B

2009-01-01

Lead, a systemic toxicant affecting virtually every organ system, primarily affects the central nervous system, particularly the developing brain. Consequently, children are at a greater risk than adults of suffering from the neurotoxic effects of lead. To date, no safe lead-exposure threshold has been identified. The ability of lead to pass through the blood-brain barrier is due in large part to its ability to substitute for calcium ions. Within the brain, lead-induced damage in the prefrontal cerebral cortex, hippocampus, and cerebellum can lead to a variety of neurologic disorders. At the molecular level, lead interferes with the regulatory action of calcium on cell functions and disrupts many intracellular biological activities. Experimental studies have also shown that lead exposure may have genotoxic effects, especially in the brain, bone marrow, liver, and lung cells. Knowledge of the neurotoxicology of lead has advanced in recent decades due to new information on its toxic mechanisms and cellular specificity. This paper presents an overview, updated to January 2009, of the neurotoxic effects of lead with regard to children, adults, and experimental animals at both cellular and molecular levels, and discusses the biomarkers of lead exposure that are useful for risk assessment in the field of environmental health.

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

NASA Astrophysics Data System (ADS)

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

2015-12-01

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

Lead in candy consumed and blood lead levels of children living in Mexico City.

PubMed

Tamayo y Ortiz, Marcela; Téllez-Rojo, Martha María; Hu, Howard; Hernández-Ávila, Mauricio; Wright, Robert; Amarasiriwardena, Chitra; Lupoli, Nicola; Mercado-García, Adriana; Pantic, Ivan; Lamadrid-Figueroa, Héctor

2016-05-01

Recent studies have shown that lead exposure continues to pose a health risk in Mexico. Children are a vulnerable population for lead effects and Mexican candy has been found to be a source of exposure in children. There are no previous studies that estimates lead concentrations in candy that children living in Mexico City consume and its association with their blood lead level. To evaluate whether there is an association between reported recent consumption of candies identified to have lead, and blood lead levels among children in Mexico City. A subsample of 171 children ages 2-6 years old, from the Early Life Exposure in Mexico to Environmental Toxicants (ELEMENT) cohort study was assessed between June 2006 and July 2007. The candy reported most frequently were analyzed for lead using ICP-MS. The total weekly intake of lead through the consumption of candy in the previous week was calculated. Capillary blood lead levels (BLL) were measured using LeadCare (anodic stripping voltammetry). Lead concentrations ≥0.1ppm, the FDA permitted level (range: 0.13-0.7ppm) were found in 6 samples out of 138 samples from 44 different brands of candy. Median BLL in children was 4.5µg/dl. After adjusting for child's sex, age, BMI, maternal education & occupation, milk consumption, sucking the candy wrapper, use of lead-glazed pottery, child exposure behavior, living near a lead exposure site and use of folk remedies, an increase of 1µg of lead ingested through candy per week was associated with 3% change (95% CI: 0.1%, 5.2%) in BLL. Although lead concentrations in candy were mostly below the FDA permitted level, high lead concentrations were detected in 4% of the candy samples and 12% of brands analyzed. Although candy intake was modestly associated with children's BLL, lead should not be found in consumer products, especially in candy that children can consume due to the well documented long-lasting effect of lead exposure. Copyright © 2016 Elsevier Inc. All rights reserved.

Prioritizing environmental justice and equality: diesel emissions in southern California.

PubMed

Marshall, Julian D; Swor, Kathryn R; Nguyen, Nam P

2014-04-01

Existing environmental policies aim to reduce emissions but lack standards for addressing environmental justice. Environmental justice research documents disparities in exposure to air pollution; however, little guidance currently exists on how to make improvements or on how specific emission-reduction scenarios would improve or deteriorate environmental justice conditions. Here, we quantify how emission reductions from specific sources would change various measures of environmental equality and justice. We evaluate potential emission reductions for fine diesel particulate matter (DPM) in Southern California for five sources: on-road mobile, off-road mobile, ships, trains, and stationary. Our approach employs state-of-the-science dispersion and exposure models. We compare four environmental goals: impact, efficiency, equality, and justice. Results indicate potential trade-offs among those goals. For example, reductions in train emissions produce the greatest improvements in terms of efficiency, equality, and justice, whereas off-road mobile source reductions can have the greatest total impact. Reductions in on-road emissions produce improvements in impact, equality, and justice, whereas emission reductions from ships would widen existing population inequalities. Results are similar for complex versus simplified exposure analyses. The approach employed here could usefully be applied elsewhere to evaluate opportunities for improving environmental equality and justice in other locations.

Multiple presentations reduce the behavioral impact of protected predator exposure in rats.

PubMed

Genovese, Raymond F; Johnson, Christina C; Tobin, Christine A; Gauchan, Sangeeta

2014-10-01

Exposure of rats to a predator species, such as a cat, or stimuli associated with a predator species has been used to model the effects of traumatic stress. We further investigated this procedure to determine if the behavioral effects from such exposure could be increased by multiple exposures. In rats (n=8 for each treatment group), we evaluated single (1×) and multiple (1×/day for 3 consecutive days [3×] and 2×/day for 3 consecutive days [6×]) exposures using cats and soiled cat litter. All exposures were 15min in duration and the rats were directly exposed to the cats but in a protected fashion that did not allow the predator to physically injure the rat. Sham exposures were conducted using similar conditions without the presence of the predator or litter. The effects of the exposures were evaluated using an elevated plus maze (EPM). Sessions on the EPM were conducted before the exposures and at various times after the exposure. Difference scores (post-pre) were calculated for dependent measures from the EPM, and statistical analyses compared the slopes and intercept values derived from regression functions from these scores over the post-exposure sessions. During the first 30 days after exposure, a significant reduction in activity on the EPM was observed for the 1× treatment and a smaller reduction was observed for the 3× treatment, but no reduction was observed for the 6× and sham control treatments. Thus, increasing the number of exposures did not increase the magnitude of the effect but, instead, resulted in a decrease. These results show that adaptation to the effects of the predator exposure occurred with repeated sessions. Published by Elsevier B.V.

Stratospheric ozone changes under solar geoengineering: implications for UV exposure and air quality

NASA Astrophysics Data System (ADS)

Nowack, Peer Johannes; Abraham, Nathan Luke; Braesicke, Peter; Pyle, John Adrian

2016-03-01

Various forms of geoengineering have been proposed to counter anthropogenic climate change. Methods which aim to modify the Earth's energy balance by reducing insolation are often subsumed under the term solar radiation management (SRM). Here, we present results of a standard SRM modelling experiment in which the incoming solar irradiance is reduced to offset the global mean warming induced by a quadrupling of atmospheric carbon dioxide. For the first time in an atmosphere-ocean coupled climate model, we include atmospheric composition feedbacks for this experiment. While the SRM scheme considered here could offset greenhouse gas induced global mean surface warming, it leads to important changes in atmospheric composition. We find large stratospheric ozone increases that induce significant reductions in surface UV-B irradiance, which would have implications for vitamin D production. In addition, the higher stratospheric ozone levels lead to decreased ozone photolysis in the troposphere. In combination with lower atmospheric specific humidity under SRM, this results in overall surface ozone concentration increases in the idealized G1 experiment. Both UV-B and surface ozone changes are important for human health. We therefore highlight that both stratospheric and tropospheric ozone changes must be considered in the assessment of any SRM scheme, due to their important roles in regulating UV exposure and air quality.

Effects of low-level organic selenium on lead-induced alterations in neural cell adhesion molecules.

PubMed

Wang, Mao; Fu, Hongjun; Xiao, Yongmei; Ai, Baomin; Wei, Qing; Wang, Shuyu; Liu, Tao; Ye, Liuqing; Hu, Qiansheng

2013-09-12

Low-level lead (Pb) exposure has been reported to impair the formation and consolidation of learning and memory by inhibiting the expression of neural cell adhesion molecules (NCAMs) and altering the temporal profile of its polysialylation state. In this study, we investigated whether administration of low-level organic selenium (selenomethionine, Se) at different time points could affect Pb-induced changes of NCAMs in female Wistar rats. Here we reported that the exposure of Se (60μg/kg body weight/day) at different time points significantly alleviated Pb-induced reductions in the mRNA and protein levels of NCAMs, and increases in the mRNA levels of two polysialyltransferases (St8sia II, Stx; St8sia IV, Pst) as well as the sialyltransferase activity (p<0.05). The concentrations of Pb in blood and hippocampi of Wistar rats treated with the combination of Se and Pb were significantly lower than those treated with Pb alone (p<0.05). Our results suggest that low-level organic Se can not only prevent but also reverse Pb-induced alterations in the expression and polysialylated state of NCAMs as well as the concentration of Pb in rat blood and hippocampus. © 2013 Elsevier B.V. All rights reserved.

Liver lead concentrations in raptors in New Jersey, USA, 2008-2010.

PubMed

Stansley, William; Murphy, Lisa A

2011-08-01

Lead exposure in New Jersey raptors was assessed by analyzing liver samples from carcasses obtained from wildlife rehabilitators. Samples were collected from 221 individuals representing 13 species. Concentrations were within the range of normal background exposure in 12 species. One red-tailed hawk had a liver lead concentration consistent with clinical poisoning (7.4 μg/g wet weight), which represents an incidence of 1% (1/104) in that species and 0.5% (1/221) in the overall sample. A second red-tailed hawk had a liver lead concentration consistent with subclinical exposure (2.1 μg/g wet weight). The combined incidence of elevated exposure (subclinical exposure + clinical poisoning) was 2% (2/104) in red-tailed hawks and 1% (2/221) in the overall sample.

Dandelion-enriched diet of mothers alleviates lead-induced damages in liver of newborn rats.

PubMed

Gargouri, M; Magné, C; Ben Amara, I; Ben Saad, H; El Feki, A

2017-02-28

Lead (Pb) is a highly toxic metal present in the environment. It causes disturbances of several functions, including hematologic, renal, reproductive and nervous ones. Preventive or curative use of medicinal plants against these disorders may be a promising and safe therapeutic strategy. This study evaluated the hepatic toxic effects of prenatal exposure to lead in rats and the possible protective effect of dandelion (Taraxacum officinale) added to the diet. Female rats were given a normal diet (control) or a diet enriched with dandelion (treated). In addition, lead acetate was administered to half of the rats through drinking water from the 5th day of gestation until the 14th day postpartum. Lead toxicity was evaluated in their offspring by measuring body and liver weights, plasma biochemical parameters, liver damage, as well as protein content and activities of antioxidant enzymes in the liver tissues. Lead poisoning of mothers caused lead deposition in blood and stomach of their pups as well as hepatic tissue damages. Moreover, significant decreases in liver weight and protein content were found. Lead treatment caused oxidative stress and marked changes in the activity of antioxidant enzymes. However, no damages or biochemical changes were observed in puppies from the rats co-treated with lead and dandelion. These results indicate that supplementation of pregnant and lactating rats with dandelion protects their offspring against lead poisoning, likely through reduction of oxidative stress and liver damages.

The identification of lead ammunition as a source of lead exposure in First Nations: the use of lead isotope ratios.

PubMed

Tsuji, Leonard J S; Wainman, Bruce C; Martin, Ian D; Sutherland, Celine; Weber, Jean-Philippe; Dumas, Pierre; Nieboer, Evert

2008-04-15

The use of lead shotshell to hunt water birds has been associated with lead-contamination in game meat. However, evidence illustrating that lead shotshell is a source of lead exposure in subsistence hunting groups cannot be deemed definitive. This study seeks to determine whether lead shotshell constitutes a source of lead exposure using lead isotope ratios. We examined stable lead isotope ratios for lichens, lead shotshell and bullets, and blood from residents of Fort Albany and Kashechewan First Nations, and the City of Hamilton, Ontario, Canada. Data were analyzed using ANOVA and regression analyses. ANOVA of isotope ratios for blood revealed significant differences with respect to location, but not sex. Hamilton differed from both Kashechewan and Fort Albany; however, the First Nations did not differ from each other. ANOVA of the isotope ratios for lead ammunition and lichens revealed no significant differences between lichen groups (north and south) and for the lead ammunition sources (pellets and bullets). A plot of (206)Pb/(204)Pb and (206)Pb/(207)Pb values illustrated that lichens and lead ammunition were distinct groupings and only the 95% confidence ellipse of the First Nations group overlapped that of lead ammunition. In addition, partial correlations between blood-lead levels (adjusted for age) and isotope ratios revealed significant (p<0.05) positive correlations for (206)Pb/(204)Pb and (206)Pb/(207)Pb, and a significant negative correlation for (208)Pb/(206)Pb, as predicted if leaded ammunition were the source of lead exposure. In conclusion, lead ammunition was identified as a source of lead exposure for First Nations people; however, the isotope ratios for lead shotshell pellets and bullets were indistinguishable. Thus, lead-contaminated meat from game harvested with lead bullets may also be contributing to the lead body burden.

[Effect of lead on the cardiovascular system].

PubMed

Zyśko, Dorota; Chlebda, Ewa; Gajek, Jacek

2004-11-01

Lead is a metal widely spread in the natural environment. It is strongly toxic, particularly to the peripheral and central nervous systems. The toxic influence on the cardiovascular system is most pronounced in case of higher exposures, where myocardium and the renal circulation are affected, in consequence of which secondary arterial hypertension can develop. It seems that lead affects the cardiovascular system mainly by changing the peripheral autonomic nervous system and leading to chronic neuropathy. Chronic exposure, even to low doses of lead, can impair conduction in myocardium. In order to assess those changes thoroughly prospective studies involving newly employed workers with occupational exposure to toxic activity of lead will be necessary.

Dermatopathology effects of simulated solar particle event radiation exposure in the porcine model.

PubMed

Sanzari, Jenine K; Diffenderfer, Eric S; Hagan, Sarah; Billings, Paul C; Gridley, Daila S; Seykora, John T; Kennedy, Ann R; Cengel, Keith A

2015-07-01

The space environment exposes astronauts to risks of acute and chronic exposure to ionizing radiation. Of particular concern is possible exposure to ionizing radiation from a solar particle event (SPE). During an SPE, magnetic disturbances in specific regions of the Sun result in the release of intense bursts of ionizing radiation, primarily consisting of protons that have a highly variable energy spectrum. Thus, SPE events can lead to significant total body radiation exposures to astronauts in space vehicles and especially while performing extravehicular activities. Simulated energy profiles suggest that SPE radiation exposures are likely to be highest in the skin. In the current report, we have used our established miniature pig model system to evaluate the skin toxicity of simulated SPE radiation exposures that closely resemble the energy and fluence profile of the September, 1989 SPE using either conventional radiation (electrons) or proton simulated SPE radiation. Exposure of animals to electron or proton radiation led to dose-dependent increases in epidermal pigmentation, the presence of necrotic keratinocytes at the dermal-epidermal boundary and pigment incontinence, manifested by the presence of melanophages in the derm is upon histological examination. We also observed epidermal hyperplasia and a reduction in vascular density at 30 days following exposure to electron or proton simulated SPE radiation. These results suggest that the doses of electron or proton simulated SPE radiation results in significant skin toxicity that is quantitatively and qualitatively similar. Radiation-induced skin damage is often one of the first clinical signs of both acute and non-acute radiation injury where infection may occur, if not treated. In this report, histopathology analyses of acute radiation-induced skin injury are discussed. Copyright © 2015 The Committee on Space Research (COSPAR). Published by Elsevier Ltd. All rights reserved.