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Sample records for cement dust exposure

  1. Personal exposure to inhalable cement dust among construction workers.

    Science.gov (United States)

    Peters, Susan; Thomassen, Yngvar; Fechter-Rink, Edeltraud; Kromhout, Hans

    2009-01-01

    Objective- A case study was carried out to assess cement dust exposure and its determinants among construction workers and for comparison among workers in cement and concrete production.Methods- Full-shift personal exposure measurements were performed and samples were analysed for inhalable dust and its cement content. Exposure variability was modelled with linear mixed models.Results- Inhalable dust concentrations at the construction site ranged from 0.05 to 34 mg/m(3), with a mean of 1.0 mg/m(3). Average concentration for inhalable cement dust was 0.3 mg/m(3) (GM; range 0.02-17 mg/m(3)). Levels in the ready-mix and pre-cast concrete plants were on average 0.5 mg/m(3) (GM) for inhalable dust and 0.2 mg/m(3) (GM) for inhalable cement dust. Highest concentrations were measured in cement production, particularly during cleaning tasks (inhalable dust GM = 55 mg/m(3); inhalable cement dust GM = 33 mg/m(3)) at which point the workers wore personal protective equipment. Elemental measurements showed highest but very variable cement percentages in the cement plant and very low percentages during reinforcement work and pouring. Most likely other sources were contributing to dust concentrations, particularly at the construction site. Within job groups, temporal variability in exposure concentrations generally outweighed differences in average concentrations between workers. 'Using a broom', 'outdoor wind speed' and 'presence of rain' were overall the most influential factors affecting inhalable (cement) dust exposure.Conclusion- Job type appeared to be the main predictor of exposure to inhalable (cement) dust at the construction site. Inhalable dust concentrations in cement production plants, especially during cleaning tasks, are usually considerably higher than at the construction site.

  2. Personal exposure to inhalable cement dust among construction workers.

    NARCIS (Netherlands)

    Peters, S.M.; Thomassen, Y.; Fechter-Rink, E.; Kromhout, H.

    2009-01-01

    Objective- A case study was carried out to assess cement dust exposure and its determinants among construction workers and for comparison among workers in cement and concrete production.Methods- Full-shift personal exposure measurements were performed and samples were analysed for inhalable dust and

  3. Exposure to cement dust at a Portland cement factory and the risk of cancer.

    Science.gov (United States)

    Vestbo, J; Knudsen, K M; Raffn, E; Korsgaard, B; Rasmussen, F V

    1991-01-01

    The relation between exposure to cement dust and cancer was examined in a population of 546 cement workers and a reference population of 858 randomly sampled men of similar age and area of residence. In 1974 all men gave lifelong occupational and smoking histories; information on incidence of cancer in the period 1974-85 was obtained from the Danish Cancer Registry. No increased risk of overall cancer was found among cement workers. Among men with more than 20 years exposure to cement dust, 14 cases of respiratory cancer were observed (observed/expected (O/E) 1.52, 95% confidence interval (95% CI) 0.90-2.57) when compared with all Danish men. Men with 1-20 years exposure had O/E 1.14 (95% CI 0.59-2.19) based on nine cases of cancer. After excluding all men with documented exposure to asbestos during employment in an asbestos cement factory no increased risk of overall cancer or respiratory cancer was found among cement workers compared with white collar workers from the local reference population, using a Cox regression model controlling for age and smoking habits. Relative risks were 0.5 (95% CI 0.1-1.5) and 1.0 (95% CI 0.4-2.6) for men with 1-20 and more than 20 years of exposure to cement dust respectively compared with white collar workers. PMID:1772795

  4. Cement dust exposure-related emphysema in a construction worker

    Directory of Open Access Journals (Sweden)

    V Karkhanis

    2011-01-01

    Full Text Available Although, smoking is considered the most important predisposing factor in development of emphysema; environmental exposures also play an important role. There have been several studies on work related respiratory symptoms and ventilatory disorders among employees of cement industry. We report a case of cement exposure related emphysema in 75 years old woman construction worker.

  5. Effect of duration of exposure to cement dust on respiratory function of non-smoking cement mill workers.

    Science.gov (United States)

    Meo, Sultan Ayoub; Al-Drees, Abdul Majeed; Al Masri, Abeer A; Al Rouq, Fawzia; Azeem, Muhammad Abdul

    2013-01-16

    This study aimed to determine the effect of long term exposure to cement dust on lung function in non-smoking cement mill workers. This is a cross-sectional study of respiratory functions. Spirometry was performed in 100 apparently healthy volunteers; 50 non-smoking cement mill workers and 50 non-smoking un-exposed subjects. Based on the duration of exposure, cement mill workers were divided into three groups, less than 5, 5-10 and greater than 10 years. All subjects were individually matched for age, height, weight, and socioeconomic status. Pulmonary function test was performed by using an electronic spirometer. Significant reduction was observed in the mean values of Forced Vital Capacity (FVC), Forced Expiratory Volume in one second (FEV(1)), Peak Expiratory Flow (PEF) and Maximal Voluntary Ventilation in cement mill workers who had been working in the cement industry for more than 10 years compared to their matched un-exposed group. Lung functions in cement mill workers were significantly impaired and results show a long term duration response effect of years of exposure to cement dust on lung functions.

  6. Cement Dust Exposure and Perturbations in Some Elements and Lung and Liver Functions of Cement Factory Workers

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    Egbe Edmund Richard

    2016-01-01

    Full Text Available Background. Cement dust inhalation is associated with deleterious health effects. The impact of cement dust exposure on the peak expiratory flow rate (PEFR, liver function, and some serum elements in workers and residents near cement factory were assessed. Methods. Two hundred and ten subjects (50 workers, 60 residents, and 100 controls aged 18–60 years were studied. PEFR, liver function {aspartate and alanine transaminases (AST and ALT and total and conjugated bilirubin (TB and CB}, and serum elements {lead (Pb, copper (Cu, manganese (Mn, iron (Fe, cadmium (Cd, selenium (Se, chromium (Cr, zinc (Zn, and arsenic (As} were determined using peak flow meter, colorimetry, and atomic absorption spectrometry, respectively. Data were analysed using ANOVA and correlation at p=0.05. Results. The ALT, TB, CB, Pb, As, Cd, Cr, Se, Mn, and Cu were significantly higher and PEFR, Fe, and Zn lower in workers and residents compared to controls (p<0.05. Higher levels of ALT, AST, and Fe and lower levels of Pb, Cd, Cr, Se, Mn, and Cu were seen in cement workers compared to residents (p<0.05. Negative correlation was observed between duration of exposure and PEFR (r=-0.416, p=0.016 in cement workers. Conclusions. Cement dust inhalation may be associated with alterations in serum elements levels and lung and liver functions while long term exposure lowers peak expiratory flow rate.

  7. Effect of exposure to dust on lung function of cement factory workers.

    Science.gov (United States)

    Noor, H; Yap, C L; Zolkepli, O; Faridah, M

    2000-03-01

    Exposure to Portland cement dust has long been associated with the prevalence of respiratory symptoms and varying degrees of airway obstruction in man. Apart from respiratory diseases, it was also found to be the cause of lung and laryngeal cancer, gastrointestinal tumours and also dermatitis. This study was done to investigate the effect of dust exposure on ventilatory lung function of Portland cement factory workers in Rawang, Selangor. Spirometry tests of 62 male workers (exposed to total dust concentration of 10,180 micrograms/m3 and PM10 of 8049 micrograms/m3) and 70 subjects from UPM (exposed to mean total dust of 192 micrograms/m3 and PM10 of 177 micrograms/m3--controls) revealed significant differences in spirometry values between the groups. The workers showed i) significantly lower FEV1% and FEF25-75%, and higher FMFT, ii) reduced FEV1% with increasing level of dust exposure and iii) higher prevalence of respiratory symptoms. Therefore, we suggest that exposure to dust in the cement factory leads to higher incidence of respiratory symptoms and impaired lung function.

  8. Lung function and long-term exposure to cement dust

    DEFF Research Database (Denmark)

    Rasmussen, F V; Borchsenius, L; Holstein, B

    1977-01-01

    In a cross-sectional epidemiological survey a selected group of former and present cement factory workers and a random sample of the corresponding urban population underwent dynamic spirometry. Based upon life experience the subjects were grouped into four occupational categories. Three hundred...... and one men were grouped as cement factory workers, 649 were grouped as blue collar workers, 218 as white collar workers and 102 men had predominantly been occupied in farming, forestry and fishing. On the average the investigated men had spent more than 75% of their total occupational life in their main...... throughout life had better ventilatory lung function than any of the other three occupational categories. No significant differences in lung function between cement factory workers and other blue collar workers with comparable smoking habits could be demonstrated by use of the maximal midexpiratory flow...

  9. Effects of occupational dust exposure on the health status of portland cement factory workers

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    R Manjula

    2013-07-01

    Full Text Available Introduction: Chronic exposure to Portland cement dust has been reported to lead to greater prevalence of various clinical conditions (includes both respiratory and non-respiratory. These conditions are consistently associated with the degree and duration of exposure. Regular use of appropriate personal protective equipment if made available at the work site could protect the cement factory workers from adverse health effects. Objective: To study the morbidity profile of the cement factory workers. Type of Study: Retrospective cohort study. Material and Methods: This study was conducted in the Portland Cement Factory in North Karnataka. Data was collected using predesigned questionnaire by personal interview method and clinical examination. A total of 64 male workers are randomly selected who are working in various departments like crushing, raw/cement mill, rotary kiln and packing department. Equal number of unexposed controls was selected from the area atleast 5 kms from the factory and those who are not exposed to cement dust in the past, who are matched for age, Socio economic status and smoking with the exposed population. Statistical Analysis: Chisquare test for qualitative data and unpaired t test for quantitative data using Epi info. Results: A total of 64 male workers and equal number of matched controls who are not exposed to the cement dust were included in the study. Among exposed maximum of 36% were employed in Crushing department, 25% each in Packing and cement/raw mill. Systolic and Diastolic blood pressure was found to be higher among the exposed, which is statistically highly significant (p<0.001. There is significant increase in weight among exposed (p<0.001. Maximum 29(45.3% of the workers had stuffy nose and epistaxis when compared to unexposed with Relative risk(RR of 2.6, followed by Dermatological complaints and lower respiratory complaints with RR of 2.18 and 2.3 respectively. Conclusion: Personal protective equipment

  10. Thoracic dust exposure is associated with lung function decline in cement production workers.

    Science.gov (United States)

    Nordby, Karl-Christian; Notø, Hilde; Eduard, Wijnand; Skogstad, Marit; Fell, Anne Kristin; Thomassen, Yngvar; Skare, Øivind; Bergamaschi, Antonio; Pietroiusti, Antonio; Abderhalden, Rolf; Kongerud, Johny; Kjuus, Helge

    2016-08-01

    We hypothesised that exposure to workplace aerosols may lead to lung function impairment among cement production workers.Our study included 4966 workers in 24 cement production plants. Based on 6111 thoracic aerosol samples and information from questionnaires we estimated arithmetic mean exposure levels by plant and job type. Dynamic lung volumes were assessed by repeated spirometry testing during a mean follow-up time of 3.5 years (range 0.7-4.6 years). The outcomes considered were yearly change of dynamic lung volumes divided by the standing height squared or percentage of predicted values. Statistical modelling was performed using mixed model regression. Individual exposure was classified into quintile levels limited at 0.09, 0.89, 1.56, 2.25, 3.36, and 14.6 mg·m(-3), using the lowest quintile as the reference. Employees that worked in administration were included as a second comparison group.Exposure was associated with a reduction in forced expiratory volume in 1 s (FEV1), forced expiratory volume in 6 s and forced vital capacity. For FEV1 % predicted a yearly excess decline of 0.84 percentage points was found in the highest exposure quintile compared with the lowest.Exposure at the higher levels found in this study may lead to a decline in dynamic lung volumes. Exposure reduction is therefore warranted.

  11. Effect of Exposure to Portland Cement Dust on the Periodontal Status and on the Outcome of Non-Surgical Periodontal Therapy

    Science.gov (United States)

    Abdelhamid, Alaa

    2016-01-01

    Background Cement dust contains heavy metals like nickel, cobalt, lead and chromium, pollutants hazardous to the biotic environment, with adverse impact for vegetation, human and animal health and ecosystems. Objective To investigate if long term exposure to cement dust can affect the periodontal health and affect the outcome of non-surgical periodontal therapy. Methods A total of sixty subjects were included in this study. Forty patients with chronic periodontitis were grouped into; Group I comprised of 20 patients with chronic periodontitis working in the Portland Cement Company and Group II comprised of 20 patients with chronic periodontitis who does not work in cement factories nor live near any of them. Twenty healthy subjects were included in this study as healthy control group (Group III). Clinical parameters including gingival index (GI), plaque index (PI), pocket depth (PD) and clinical attachment loss (CLA) were scored for all patients before and after periodontal therapy. All patients received non-surgical periodontal therapy together with strict oral hygiene program for one month. Gingival crevicular fluid (GCF) samples were collected from both groups at baseline and one month after periodontal therapy. Real time PCR (RT-PCR) was used to analyze the GCF samples for detection and assessment of the levels of IL-1β and TNFα. Results The two studied groups responded well to non-surgical periodontal treatment and there was no significant difference between GI and GII (P>0.05). The levels of TNFα was higher in GI than in GII before and after periodontal therapy (P0.05), but represented with a highly significant difference between G1 and GII after periodontal therapy (Psurgical periodontal treatment but it affects the levels of the pro-inflammatory mediators leading to more periodontal tissue destruction. PMID:27610057

  12. Dust exposure in Finnish foundries.

    Science.gov (United States)

    Siltanen, E; Koponen, M; Kokko, A; Engström, B; Reponen, J

    1976-01-01

    Dust measurements were made in 51 iron, 9 steel, and 8 nonferrous foundries, at which 4,316 foundrymen were working. The sampling lasted at least two entire shifts or work days continuously during various operations in each foundry. The dust samples were collected at fixed sites or in the breathing zones of the workers. The mass concentration was determined by weighing and the respirable dust fraction was separated by liquid sedimentation. The free silica content was determined by X-ray diffraction. In the study a total of 3,188 samples were collected in the foundries and 6,505 determinations were made in the laboratory. The results indicated a definite difference in the dust exposure during various operations. The highest dust exposures were found during furnace, cupola, and pouring ladle repair. During cleaning work, sand mixing, and shake-out operations excessive silica dust concentrations were also measured. The lowest dust concentrations were measured during melting and pouring operations. Moderate dust concentrations were measured during coremaking and molding operations. The results obtained during the same operations of iron and steel foundries were similar. The distribution of the workers into various exposure categories, the content of respirable dust and quartz, the correlation between respirable dust and total dust, and the correlation between respirable silica and total dust concentrations are discussed. Observations concerning dust suppression and control methods are briefly considered.

  13. Effects of cement flue dusts from a Nigerian cement plant on air, water and planktonic quality.

    Science.gov (United States)

    Olaleye, Victor F; Oluyemi, Emmanuel A

    2010-03-01

    Effects of cement flue dust from Ewekoro cement Kilns were monitored at some aquatic receptor locations. High levels of total suspended particulates (TSPs) and atmospheric deposition rates (ADRs) were recorded within the factory compared to ancillary locations outside the factory. The TSP and ADR levels which were location dependent were significantly higher (P cement factory catchment areas.

  14. Performance analysis of magnesium phosphate cement mortar containing grinding dust

    OpenAIRE

    2009-01-01

    Magnesium phosphate cement materials are formed by reacting magnesium oxide with water-soluble phosphates such as monoammonium dihydrogen phosphate (ADP), which solidifies at ambient temperature through the formation of hydrated phases in the material. Cylindrical specimens of magnesium phosphate cement were molded and varying amounts (0 to 30% weight) of grinding dust were added to the ceramic matrices. The influence of the addition of grinding dust on the characteristics of the mortars in t...

  15. Peach leaf responses to soil and cement dust pollution.

    Science.gov (United States)

    Maletsika, Persefoni A; Nanos, George D; Stavroulakis, George G

    2015-10-01

    Dust pollution can negatively affect plant productivity in hot, dry and with high irradiance areas during summer. Soil or cement dust were applied on peach trees growing in a Mediterranean area with the above climatic characteristics. Soil and cement dust accumulation onto the leaves decreased the photosynthetically active radiation (PAR) available to the leaves without causing any shade effect. Soil and mainly cement dust deposition onto the leaves decreased stomatal conductance, photosynthetic and transpiration rates, and water use efficiency due possibly to stomatal blockage and other leaf cellular effects. In early autumn, rain events removed soil dust and leaf functions partly recovered, while cement dust created a crust partially remaining onto the leaves and causing more permanent stress. Leaf characteristics were differentially affected by the two dusts studied due to their different hydraulic properties. Leaf total chlorophyll decreased and total phenol content increased with dust accumulation late in the summer compared to control leaves due to intense oxidative stress. The two dusts did not cause serious metal imbalances to the leaves, except of lower leaf K content.

  16. Ecophysiological and ultrastructural effects of dust pollution in lichens exposed around a cement plant (SW Slovakia).

    Science.gov (United States)

    Paoli, Luca; Guttová, Anna; Grassi, Alice; Lackovičová, Anna; Senko, Dušan; Sorbo, Sergio; Basile, Adriana; Loppi, Stefano

    2015-10-01

    The study investigated the ecophysiological and ultrastructural effects of dust pollution from a cement industry in the lichen species Evernia prunastri and Xanthoria parietina, which were exposed for 30, 90 and 180 days around a cement mill, two quarries, and inhabited and agricultural sites in SW Slovakia. The results showed that dust deposition from quarrying activities and cement works at the cement mill (mainly enriched in Ca, Fe and Ti) significantly affected the photosynthetic apparatus of E. prunastri (sensitive to dust and habitat eutrophication), while X. parietina (tolerant to dust and habitat eutrophication) adapted to the new environment. The length of the exposure strongly affected the vitality of the mycobiont (measured as dehydrogenase activity) in transplanted lichens. Dust deposition led to ultrastructural alterations, including lipid droplets increase, swelling of cellular components, thylakoid degeneration and sometimes plasmolysis, which, on the whole, gave the cells an aged appearance. Photosynthetic parameters deserve further attention as potential indicators for monitoring early biological symptoms of the air pollution caused during cement production.

  17. Leaf structural traits of tropical woody species resistant to cement dust.

    Science.gov (United States)

    Siqueira-Silva, Advanio Inácio; Pereira, Eduardo Gusmão; Modolo, Luzia Valentina; Paiva, Elder Antonio Sousa

    2016-08-01

    Cement industries located nearby limestone outcrops in Brazil have contributed to the coating of cement dust over native plant species. However, little is known about the extent of the response of tropical woody plants to such environmental pollutant particularly during the first stages of plant development and establishment. This work focused on the investigation of possible alterations in leaf structural and ultrastructural traits of 5-month-old Guazuma ulmifolia Lam. (Malvaceae), 6-month-old Myracrodruon urundeuva Allemão (Anacardiaceae), and 9-month-old Trichilia hirta L. (Meliaceae) challenged superficially with cement dust during new leaf development. Leaf surface of plants, the soil or both (leaf plus soil), were treated (or not) for 60 days, under controlled conditions, with cement dust at 2.5 or 5.0 mg cm(-2). After exposure, no significant structural changes were observed in plant leaves. Also, no plant death was recorded by the end of the experiment. There was also some evidence of localized leaf necrosis in G. ulmifolia and T. hirta, leaf curling in M. urundeuva and T. hirta, and bulges formation on epidermal surface of T. hirta, after cement dust contact with plant shoots. All species studied exhibited stomata obliteration while T. hirta, in particular, presented early leaf abscission, changes in cellular relief, and organization and content of midrib cells. No significant ultrastructural alterations were detected under the experimental conditions studied. Indeed, mesophyll cells presented plastids with intact membrane systems. The high plant survival rates, together with mild morphoanatomic traits alterations in leaves, indicate that G. ulmifolia is more resistant to cement dust pollutant, followed by M. urundeuva and T. hirta. Thus, the three plant species are promising for being used to revegetate areas impacted by cement industries activities.

  18. Performance analysis of magnesium phosphate cement mortar containing grinding dust

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    Daniel Véras Ribeiro

    2009-03-01

    Full Text Available Magnesium phosphate cement materials are formed by reacting magnesium oxide with water-soluble phosphates such as monoammonium dihydrogen phosphate (ADP, which solidifies at ambient temperature through the formation of hydrated phases in the material. Cylindrical specimens of magnesium phosphate cement were molded and varying amounts (0 to 30% weight of grinding dust were added to the ceramic matrices. The influence of the addition of grinding dust on the characteristics of the mortars in terms of microstructure (SEM, mechanical strength and capillary water absorption was verified. The results obtained proved very satisfactory for the use of this waste as an additive in magnesium phosphate mortars.

  19. Analysis on occupational exposure levels and control effectiveness of dust in cement production line of new dry method%新型干法水泥生产线粉尘职业暴露水平及控制效果

    Institute of Scientific and Technical Information of China (English)

    王德军; 隋少峰; 孔凡玲; 黄东海

    2012-01-01

    Objective To investigate the occupational exposure levels of dust in new suspension preheater dry process (NSP) cement production line and put forward rectification measures for dust-exposed posts,and to provide ideas for the modern cement production enterprises in dust control and occupational health management.Methods Occupational health field investigation combined with field test were used to measure the time-weighted average concentration (CTWA) of the dust in the workplace.Rectification measures were taken for the dust-exposed posts with unqualified dust concentration,and the protective effects of dustproof facilities in the rectified workplace were evaluated.Results The field investigation revealed incompletely closed dustproof facilities,improperly set dust hoods,excess of dust leakage points,and other problems in the dust-exposed posts of an NSP cement production line before rectification,and the dustproof facilities could hardly exert dust removal effect.The field test showed that the vast majority of dust-exposed posts had the dust concentrations exceeding the occupational exposure limits (OELs),with a qualified rate as low as 31.8%.A series of rectification measures were taken for these posts.After the rectification,the dust-exposed posts demonstrated dramatically dropped CTWA,and the qualified rate of dust concentration in the dust-exposed posts rose to 90.9%.Conclusion The dust hazards in NSP cement production line cannot be ignored.Taking appropriate protective measures are critical for curbing dust hazards in modern cement production.%目的 了解新型干法水泥生产线粉尘职业暴露水平,提出整改治理措施,为现代水泥生产企业的粉尘治理及职业卫生管理提供思路.方法 采用职业卫生现场调查和现场检测相结合的方法,测定工作场所粉尘时间加权平均浓度(CTWA),对粉尘浓度不合格的作业岗位进行整改治理,评估整改粉尘作业场所防尘设施的防护效果.结果

  20. Characteristics of Portland blast-furnace slag cement containing cement kiln dust and active silica

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    A. Abdel Rahman

    2016-09-01

    Full Text Available This investigation dealt with the effect of active silica, silica fume (SF or rice husk ash (RHA, on the mechanical and physico-chemical characteristics of the hardened blended cement pastes made of Portland blast-furnace slag cement (PSC containing cement kiln dust (CKD cured under normal conditions. Two blends made of PSC and CKD, improved by SF and two blends made of PSC and CKD improved by RHA were investigated. Hardened blended cement pastes were prepared from each cement blend by using water/cement ratio (W/C of 0.30 by weight and hydrated for various curing ages of 1, 3, 7, 28 and 90 days at the normal curing conditions under tap water at room temperature. Each cement paste was tested for its physico-chemical and mechanical characteristics; these characteristics include: compressive strength and kinetics of hydration. The phase composition of the formed hydration products was identified using X-ray diffraction (XRD and differential thermal analysis (DTA. It was found that the partial substitution of PSC by 10% and 15% of CKD is associated with an increase in the rate of hydration and a subsequent improvement of compressive strength of hardened PSC–CKD pastes. In addition, the replacement of PSC, in PSC–CKD blends, by 5% active silica was accompanied by further improvement of the physico-mechanical characteristics of the hardened PSC–CKD pastes.

  1. Hydrothermal Characteristics of Blended Cement Pastes Containing Silica Sand Using Cement Kiln Dust as an Activator

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The hydrothermal reactivity of silica sand was studied using cement kiln dust (CKD) as an activator in addition to the Portlandcement fraction of El-Karnak cement (a blend of ordinary Portland cement and ground sand). Autoclaved El-Karnak cementpastes were studied at pressures of 0.507, 1.013 and 1.520 MPa of saturated steam with respect to their compressive strength,kinetics of hydrothermal reaction and the phase composition of the formed hydrates. The role of CKD in affecting thephysicochemical and mechanical properties of El-Karnak cement pastes was studied by autoclaving of several pastes containing5, 7.5, 10 and 20% CKD at a pressure of 1.013 MPa of saturated steam. CKD was added either as a raw CKD (unwashed) orafter washing with water (washed CKD). The results of these physicochemical studies obtained could be related as much aspossible to the role of CKD (raw or washed) in affecting the hydrothermal reactivity of silica sand in El-Karnak cement pastes.

  2. AIR POLLUTION CONTROL THROUGH KILN RECYCLING BY-PASS DUST IN A CEMENT FACTORY

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    F. Mohsenzadeh, J. Nouri, A. Ranjbar, M. Mohammadian Fazli, A. A. Babaie

    2006-01-01

    Full Text Available Air pollution is a major problem in the industrial areas. Cement dust is one of the important environmental pollutants. In this study the possibility of dust recycling especially kiln dust which has significant importance regarding air pollution in the cement plant, was examined. Tehran cement factory is one of the most important Iranian factories which is located in Tehran. This factory produces high volume of pollutants that are released to in environment. The possibility of reusing of kiln by pass returned dust has been examined in this factory. Different percentages of kiln by-pass dust of this factory were added to products and outcomes of its presence in parameters such as chemical compound, granulation, primary and final catch time, volume expansion, consumed water and resistance of mortar were surveyed. The result indicated that by adding the amounts of 3-8 dust the mortar resistance increase, but adding more than 15%, the mortar resistance has been decreased. Survey in consumed water proved that adding dust to cement, the trend for consuming water is decreased. After dust addition dust, primary and final catch time were compared in different samples and data which showed decrease in dust added samples. Cements with dust added showed increase in auto clave expansion. Overally, results proved that, the best percentage rate of dust addition to the cement was 15%.

  3. Effect of Heavy Metal Present in Cement Dust on Soil and Plants of Nokha (Bikaner)

    OpenAIRE

    Dr.(Mrs).Suruchi Gupta; Sarika Sharma

    2013-01-01

    In Nokha(Bikaner) cement industries emittes cement dust in nearby farmers fields. In these industries cement dust emitted contains traces of hexavalent chromium and lead well above permissible limit in area under investigation. However, cadmium and nickel were found below limits prescribed. To analyse heavy metals viz, Cr+6, lead, Cadmium and nickel one hundred and twenty samples were collected from four directions on surface and 20 cm depth, and analyzed on atomic absorption spectrophotomete...

  4. Partial Replacement of Cement with Marble Dust Powder

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    Mr. Ranjan Kumar

    2015-08-01

    Full Text Available The waste generated from the industries cause environmental problems. Hence the reuse of this waste material can be emphasized. MarbleDust Powder (MDP is a developing composite materialthatwillallow the concrèteindustry to optimisemateriel use, generateeconomicbenefits and build structures thatwillstrong, durable and sensitive to environnement. MDP is by-product obtained during the quarrying process from the parent marble rock; which contains high calcium oxide content of more than 50%. The potential use of MDP can be an ideal choice for substituting in a cementitious binder as the reactivity efficiency increases due to the presence of lime. In this research work, the waste MDP passing through 90 microns,has used for investigating of hardened concrete properties. Furthermore, the effect of different percentage replacement of MDP on the compressive strength, splitting tensile strength (indirect tensile strength&flexural strength has been observed. Inthis experimental study, the effect of MDP in concrete on strength ispresented. Five concrete mixtures containing 0%, 5%, 10%, and 20% MDP as cement replacement by weightbasis has been prepared. Water/cement ratio (0.43 was kept constant, in all the concretemixes. Compressive strength, split tensile strength & flexural strength of the concrete mixtures has been obtainedat 7 and 28 days. The results of the laboratory work showed thatreplacement of cement with MDP increase, upto 10% for compressive strength,&upto 15% for split tensilestrength &flexural strength of concrete.

  5. Stabilization/solidification of selenium-impacted soils using Portland cement and cement kiln dust

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Deok Hyun, E-mail: dmoon10@hotmail.com [W.M. Keck Geoenvironmental Laboratory, Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ 07030 (United States); Department of Environmental Engineering, Chosun University, Gwangju 501-759 (Korea, Republic of); Grubb, Dennis G. [W.M. Keck Geoenvironmental Laboratory, Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ 07030 (United States); Schnabel Engineering, LLC, 510 East Gay Street, West Chester, PA 19380 (United States); Reilly, Trevor L. [W.M. Keck Geoenvironmental Laboratory, Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ 07030 (United States)

    2009-09-15

    Stabilization/solidification (S/S) processes were utilized to immobilize selenium (Se) as selenite (SeO{sub 3}{sup 2-}) and selenate (SeO{sub 4}{sup 2-}). Artificially contaminated soils were prepared by individually spiking kaolinite, montmorillonite and dredged material (DM; an organic silt) with 1000 mg/kg of each selenium compound. After mellowing for 7 days, the Se-impacted soils were each stabilized with 5, 10 and 15% Type I/II Portland cement (P) and cement kiln dust (C) and then were cured for 7 and 28 days. The toxicity characteristic leaching procedure (TCLP) was used to evaluate the effectiveness of the S/S treatments. At 28 days curing, P doses of 10 and 15% produced five out of six TCLP-Se(IV) concentrations below 10 mg/L, whereas only the 15% C in DM had a TCLP-Se(IV) concentration <10 mg/L. Several treatments satisfied the USEPA TCLP best demonstrated available technology (BDAT) limits (5.7 mg/L) for selenium at pozzolan doses up to 10 times less than the treatments that established the BDAT. Neither pozzolan was capable of reducing the TCLP-Se(VI) concentrations below 25 mg/L. Se-soil-cement slurries aged for 30 days enabled the identification of Se precipitates by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM)-energy dispersive X-ray spectroscopy (EDX). XRD and SEM-EDX analyses of the Se(IV)- and Se(VI)-soil-cement slurries revealed that the key selenium bearing phases for all three soil-cement slurries were calcium selenite hydrate (CaSeO{sub 3}.H{sub 2}O) and selenate substituted ettringite (Ca{sub 6}Al{sub 2}(SeO{sub 4}){sub 3}(OH){sub 12}.26H{sub 2}O), respectively.

  6. Effect of kiln dust from a cement factory on growth of Vicia faba L.

    Science.gov (United States)

    Uysal, Ismet; Ozdilek, Hasan Göksel; Oztürk, Münir

    2012-04-01

    This study was undertaken to study the effects of different amounts of kiln dust mixed with soil on the seed germination, plant growth, leaf area and water content of Vicia faba cv. Eresen. The reason for this was that cement kiln dust generated as a by-product from the cement factories is rich in potassium, sulfate and other compounds. This product becomes a serious problem when it comes in contact with water. The dust was collected from a cement factory located in Canakkale. Various elements such as Al, Co, Mo, Ca, B, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, S, Se and Zn were determined both in soil as well as kiln dust. Kiln dust was mixed with soil in pots (20 cm diameter) to make seven different treatments varying from 15 to 105 g kiln dust kg(-1) of soil. The experiment lasted for 4 months. Seeds of V faba were sown in the pots filled with mixtures of preanalysed kiln dust and soil. Germination was high in the pots with a lower treatment of cement kiln dust. However, lower germination rates were observed in the pots mixed with the highest and the medium amounts of cement kiln dust. Plants growing in the soil including 15 g kiln dust showed better performance in length as compared to control. Leaf area increased with increase in cement kiln dust content up to 60 g kiln dust kg(-1) of soil, but declined after 75 g kg(-1). Water content of leaves (mg cm(-2) leaf area) was found to be constantly decreasing with respect to increasing cement kiln content in the pots. Differences between the averages were evaluated by Tukey test and results were found to be significant.

  7. Stabilization/solidification of selenium-impacted soils using Portland cement and cement kiln dust.

    Science.gov (United States)

    Moon, Deok Hyun; Grubb, Dennis G; Reilly, Trevor L

    2009-09-15

    Stabilization/solidification (S/S) processes were utilized to immobilize selenium (Se) as selenite (SeO(3)(2-)) and selenate (SeO(4)(2-)). Artificially contaminated soils were prepared by individually spiking kaolinite, montmorillonite and dredged material (DM; an organic silt) with 1000 mg/kg of each selenium compound. After mellowing for 7 days, the Se-impacted soils were each stabilized with 5, 10 and 15% Type I/II Portland cement (P) and cement kiln dust (C) and then were cured for 7 and 28 days. The toxicity characteristic leaching procedure (TCLP) was used to evaluate the effectiveness of the S/S treatments. At 28 days curing, P doses of 10 and 15% produced five out of six TCLP-Se(IV) concentrations below 10mg/L, whereas only the 15% C in DM had a TCLP-Se(IV) concentration phases for all three soil-cement slurries were calcium selenite hydrate (CaSeO(3).H(2)O) and selenate substituted ettringite (Ca(6)Al(2)(SeO(4))(3)(OH)(12).26H(2)O), respectively.

  8. Effect of Heavy Metal Present in Cement Dust on Soil and Plants of Nokha (Bikaner

    Directory of Open Access Journals (Sweden)

    Dr.(Mrs.Suruchi Gupta

    2013-08-01

    Full Text Available In Nokha(Bikaner cement industries emittes cement dust in nearby farmers fields. In these industries cement dust emitted contains traces of hexavalent chromium and lead well above permissible limit in area under investigation. However, cadmium and nickel were found below limits prescribed. To analyse heavy metals viz, Cr+6, lead, Cadmium and nickel one hundred and twenty samples were collected from four directions on surface and 20 cm depth, and analyzed on atomic absorption spectrophotometer. From the above study it is clear that in case of Sarvottam cement works only lead content was higher in all directions and depths than other two plants. At tiger and Nokha cement works contamination of lead was more over limited in the first 1 km except in east direction. Mobility of lead was relatively more on top soil than 20cm depth. Hexavalent chromium content in south western direction was more for Nokha cement. Whereas, it was more in east direction in case of tiger cement. This indicated influence of prevailing direction of wind on distribution of heavy metals present in cement dust.Heavy metal toxicity results in reduction in plant height, burning of leaf margins and tip, slow leaf growth and over all wilting of Prosopis cineraria, Pearlmillet and clusterbean plants, when this metal deposits in Human body results in genetic disorders. Electrostatic precipitator can be installed to reduce the cement dust emission.

  9. A New Kind of Eco-Cement Made of Cement Kiln Dust and Granular Blast Furnace Slag

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A research project was conducted to manufacture eco-cement for sustainable development using cement kiln dust( CKD ) and granular blast furnace slag( GBFS ).In the project, the burning process and mineral compositions of CKD clinker were investigated.Dife rent mineralizers such as CaSO4 and CaF2 , sulfur and alkali content were considered.The strength of CKD and GBFS eco-cement were evaluated.The results indicate the CKD clinker can not only form ordinary cement clinker minerals such as C3 S, C2 S and C4 AF, but also form strength to the Portland cement grade 32.5 when blend proportion is properly applied.

  10. Germination of Medicago sativa is inhibited by soluble compounds in cement dust.

    Science.gov (United States)

    Lafragüeta, Cristina; García-Criado, Balbino; Arranz, Angel; Vázquez-de-Aldana, Beatriz R

    2014-01-01

    Deposition of cement dust on soils and plant surfaces is known to affect plant growth and the species composition of plant communities, but little is known about its effects (and those of its pH and constituents) on germination. Therefore, the aim of this study was to assess the toxicity of an aqueous cement extract, constituents of the extract and pH on the germination of seeds of a selected species, Medicago sativa. First, the effects of the extract were tested in assays with concentrations and exposure durations ranging from 0 to 1.0 g/mL and 4 to 96 h, respectively. At 0.8 g/mL, the extract strongly inhibited germination; a 4-h exposure reduced the germination rate, from 77 ± 1.8 to 50 ± 2.6% (mean ± SE), while 8-h exposure completely inhibited it. Further, treatment at this concentration killed the non-germinating seeds, thus the inhibition was due to toxic effects. Neither the pH of the extract nor the concentration of its main soluble elements separately (K, Ca, S, Na, or Cr) caused the toxicity since germination rates were not significantly reduced when these variables were tested individually. However, a mixture of the elements in solution reduced germination rates, suggesting that they have adverse synergistic effects.

  11. Silica dust exposures during selected construction activities.

    Science.gov (United States)

    Flanagan, Mary Ellen; Seixas, Noah; Majar, Maria; Camp, Janice; Morgan, Michael

    2003-01-01

    This study characterized exposure for dust-producing construction tasks. Eight common construction tasks were evaluated for quartz and respirable dust exposure by collecting 113 personal task period samples for cleanup; demolition with handheld tools; concrete cutting; concrete mixing; tuck-point grinding; surface grinding; sacking and patching concrete; and concrete floor sanding using both time-integrating filter samples and direct-reading respirable dust monitors. The geometric mean quartz concentration was 0.10 mg/m(3) (geometric standard deviation [GSD]=4.88) for all run time samples, with 71% exceeding the threshold limit value. Activities with the highest exposures were surface grinding, tuck-point grinding, and concrete demolition (GM[GSD] of 0.63[4.12], 0.22[1.94], and 0.10[2.60], respectively). Factors recorded each minute were task, tool, work area, respiratory protection and controls used, estimated cross draft, and whether anyone nearby was making dust. Factors important to exposure included tool used, work area configuration, controls employed, cross draft, and in some cases nearby dust. More protective respirators were employed as quartz concentration increased, although respiratory protection was found to be inadequate for 42% of exposures. Controls were employed for only 12% of samples. Exposures were reduced with three controls: box fan for surface grinding and floor sanding, and vacuum/shroud for surface grinding, with reductions of 57, 50, and 71%, respectively. Exposures were higher for sweeping compound, box fan for cleanup, ducted fan dilution, and wetted substrate. Construction masons and laborers are frequently overexposed to silica. The usual protection method, respirators, was not always adequate, and engineering control use was infrequent and often ineffective.

  12. Impact of cement dust pollution on Cedrela fissilis Vell. (Meliaceae): A potential bioindicator species.

    Science.gov (United States)

    Siqueira-Silva, Advanio Inácio; Pereira, Eduardo Gusmão; Modolo, Luzia Valentina; Lemos-Filho, José Pires; Paiva, Elder Antonio Sousa

    2016-09-01

    Considering the impacts caused to vegetation in the vicinity of cement factories, the aim of this study was to evaluate the impacts of cement dust on the structural organization and physiological/biochemical traits of Cedrela fissilis leaflets, a woody species native to tropical America. Plants were exposed to 2.5 or 5 mg cm-2 cement dust applied to the leaf surface, to the soil or simultaneously to the leaf surface and the soil.. Leaves of shoot-treated plants exhibited chlorosis, marginal and inter veins necrosis, diminished thickness, epidermal cells less turgid, cellular collapse, obstructed stomata, senescence, rolling and some abscission. In few cases, individual death was recorded. Cement dust-treated plants also presented decreased amount of photosynthetic pigments and iron (Fe) and increase in calcium (Ca) levels. The cement crust formed in leaves surface blocked from 30 to 50% of the incoming light and reduced the stomatal conductance and the potential quantum yield of photosystem II. Control or soil-treated plants did not exhibit morphophysiological changes throughout the experiment. The activity of superoxide dismutase, catalase and ascorbate peroxidase increased in leaves of plants upon treatment with 2.5 mg cm(-2) cement dust, independent of the site application. Overall, these results indicate that C. fissilis is highly sensitive to cement dust at the initial stage of development.

  13. Dust exposures in the wood processing industry.

    Science.gov (United States)

    Alwis, U; Mandryk, J; Hocking, A D; Lee, J; Mayhew, T; Baker, W

    1999-01-01

    Workers at four different woodworking processes--two logging sites, four sawmills, one major woodchipping operation, and five joineries situated in the state of New South Wales in Australia--were studied for personal inhalable dust exposures (N = 182). The geometric mean exposure at logging sites was 0.6 mg/m3 (N = 7), sawmills 1.6 mg/m3 (N = 93), woodchipping 1.9 mg/m3 (N = 9), and joineries 3.7 mg/m3 (N = 66). Overall, 62% of the exposures exceeded the current standards. Among joineries, 95% of the hardwood exposures and 35% of the softwood exposures were above the relevant standards. A majority of workers (approximately 90%) did not wear appropriate respirators approved for wood dust, while the ones who did wear them, used them on average less than 50% of the time. The significant determinants of personal wood dust exposures (n = 163) were found to be local exhaust ventilation, job title, use of handheld tools, cleaning method used, use of compressed air, and green or dry wood processed. Type of wood processed (softwood or hardwood) was not found to be statistically significant.

  14. The effect of various types of cement dust on sulphur dioxide oxidation in the air.

    Science.gov (United States)

    Vadjić, V; Gentilizza, M; Halle, R

    1988-07-01

    The effect of various types of cement dust on the behaviour of sulphur dioxide in the air was investigated on model systems in different experimental conditions.Experiments were carried out with PC-15z-45s (Portland-blast furnace cement containing 15% blast furnace slag), PC-25p-35s (Portland-pozzolan cement containing 25% pozzolan) and EFD (electrofilter dust).EFD most effectively removed SO2 from the air stream. The next efficacious was PC-15z-45s, whereas PC-25p-35s was the least efficient. The efficacy of cement dusts for SO2 removal from the air stream depended on their chemical and granulometric composition and in particular on the size of specific surface.The rate of reaction was also influenced by experimental conditions-relative humidity, the length of contact, that is, the flow rate of gaseous mixture through the reactor, and the amount of cement dust.The experimental data show that in the contact between SO2 and cement dust catalytic oxidation of SO2 to sulphates takes place. Sulphates remain bound to the surface, from which they cannot be thermally desorbed, but can be released by extraction in the Soxhlet apparatus.

  15. Characterization and utilization of cement kiln dusts (CKDs) as partial replacements of Portland cement

    Science.gov (United States)

    Khanna, Om Shervan

    The characteristics of cement kiln dusts (CKDs) and their effects as partial replacement of Portland Cement (PC) were studied in this research program. The cement industry is currently under pressure to reduce greenhouse gas (GHG) emissions and solid by-products in the form of CKDs. The use of CKDs in concrete has the potential to substantially reduce the environmental impact of their disposal and create significant cost and energy savings to the cement industry. Studies have shown that CKDs can be used as a partial substitute of PC in a range of 5--15%, by mass. Although the use of CKDs is promising, there is very little understanding of their effects in CKD-PC blends. Previous studies provide variable and often conflicting results. The reasons for the inconsistent results are not obvious due to a lack of material characterization data. The characteristics of a CKD must be well-defined in order to understand its potential impact in concrete. The materials used in this study were two different types of PC (normal and moderate sulfate resistant) and seven CKDs. The CKDs used in this study were selected to provide a representation of those available in North America from the three major types of cement manufacturing processes: wet, long-dry, and preheater/precalciner. The CKDs have a wide range of chemical and physical composition based on different raw material sources and technologies. Two fillers (limestone powder and quartz powder) were also used to compare their effects to that of CKDs at an equivalent replacement of PC. The first objective of this study was to conduct a comprehensive composition analysis of CKDs and compare their characteristics to PC. CKDs are unique materials that must be analyzed differently from PC for accurate chemical and physical analysis. The present study identifies the chemical and physical analytical methods that should be used for CKDs. The study also introduced a method to quantify the relative abundance of the different

  16. Cement dust pollution induces toxicity or deficiency of some essential elements in wild plants growing around a cement factory.

    Science.gov (United States)

    Mutlu, Salih; Atici, Ökkes; Gülen, Yasir

    2013-06-01

    In the present study, it was aimed to determine the effects of cement dust pollution on contents of some significant essential elements (P, S, K, Ca, Fe and Cl) in wild plants (Medigago varia, Anchusa leptophylla, Euphorbia orientalis, Lactuca serriola, Artemisia spicigera, Crambe orientalis, Convolvulus sepium and Senecio vernalis) using wavelength-dispersive spectrometer X-ray fluorescence technique. Plant samples were collected from different locations around a cement factory which is located at Askale about 50 km from Erzurum (Turkey). The element contents in the plant specimens that existed in both 0-100 m (dense dusted) and 2000 m (undusted) areas were compared. P, S, K and Cl contents were found to be high in the plants growing in areas 0-100 m from the cement factory, compared to same plants at 2000 m far from the factory. However, Ca and Fe contents were determined to be low in plants growing in 0-100 m area from the factory. Results of the study can contribute to understand how mineral deficiency and toxicity lead to detrimental effects on plant growth and development in the fields contaminated by cement dust.

  17. Biomonitoring spatial and temporal impact of atmospheric dust from a cement industry

    Energy Technology Data Exchange (ETDEWEB)

    Branquinho, Cristina [Universidade de Lisboa, Faculdade de Ciencias, Centro de Ecologia e Biologia Vegetal, Campo Grande, Edificio C2, Piso 4, 1749-016 Lisbon (Portugal); Universidade Atlantica, Antiga Fabrica da Polvora de Barcarena, 2745-615 Barcarena (Portugal)], E-mail: cmbranquinho@fc.ul.pt; Gaio-Oliveira, Gisela; Augusto, Sofia; Pinho, Pedro; Maguas, Cristina; Correia, Otilia [Universidade de Lisboa, Faculdade de Ciencias, Centro de Ecologia e Biologia Vegetal, Campo Grande, Edificio C2, Piso 4, 1749-016 Lisbon (Portugal)

    2008-01-15

    The objective of this work was to evaluate the spatial and temporal impact of dust-pollution in the vicinity of a cement industry, located in an area with dry climate. The spatial impact integrated over time was evaluated from the concentrations of Ca, Fe and Mg in in-situ Xanthoria parietina. The temporal pattern was assessed through one-month transplants of the lichen Ramalina canariensis. Four potential sources of atmospheric dust were evaluated: the limestone-quarry; the unpaved roads, the deposit area and the cement mill. Calcium concentration in lichens was considered the best cement-dust indicator. Different types of dust (clinker and grinded-limestone-dust) resulted in different time-patterns of Ca accumulation, which was also related with the different influence that wet and dry periods have in the lichen accumulation process. The dust pollution was found to be deposited locally and dependent on: the nature of dust particles and the volume and frequency of precipitation. - Biomonitoring Spatial and Temporal dust emissions in dry climates.

  18. Lung function: occupational exposure to wood dust

    Directory of Open Access Journals (Sweden)

    Baran S

    2009-12-01

    Full Text Available Abstract Objectives Occupational exposure to wood dust has been shown to cause several respiratory disorders, such as allergic rhinitis, chronic bronchitis, asthma, sino-nasal adenocarcinoma, and impairment of lung function. The aim of the study was to estimate lung function (in the woodworking industry among workers employed by wood processing, who run the risk of being expose to wood dust. Methods The study concerns a group of 70 workers aged 24-55. All the workers underwent general and laryngological examination. A group of 20 workers, working at the positions where dustiness exceeded TLV (threshold limit value took X-ray of the chest and spirometry. The following parameters were measured: VC, IC, ERV, TV, BF, FEV1, FVC, PEF, MEF25-75, FEV1%FVC, FEV1%VC. The data are presented as means ± SD and the authors applied references values according to ERS guidelines. Results The results show that there was no decline in FEV1 (3.7 ± 0.7 and FVC (4.5 ± 0.8. Normal lung function was defined as FEV1/VC ratio ≥0.7. None of the tested workers had obstructive pattern in spirometry. The mean FEV1%VC was 77.1 ± 10.2. These results suggest that wood dust exposure might not lead to significant pulmonary damage. Conclusions These data do not corroborate that wood dust plays significant role in lung function impairment. Future studies of respiratory health among workers exposed to wood dust are needed.

  19. Dust exposure and pneumoconiosis in a South African pottery. 1. Study objectives and dust exposure.

    Science.gov (United States)

    Rees, D; Cronje, R; du Toit, R S

    1992-07-01

    Dust exposure and pneumoconiosis were investigated in a South African pottery that manufactured wall tiles and bathroom fittings. This paper describes the objectives of the investigation and presents dust measurement data. x Ray diffraction showed that the clays used by the pottery had a high quartz content (range 58%-23%, mean 38%). Exposure to respirable dust was measured for 43 workers and was highest (6.6 mg/m3) in a bathroom fitting fettler. Quartz concentrations in excess of 0.1 mg/m3 were found in all sections of the manufacturing process from slip production to biscuit firing and sorting. The proportion of quartz in the respirable dust of these sections was 24% to 33%. This is higher than is usually reported in English potteries. Four hundred and six (80%) of the 509 workers employed at the pottery were potentially at risk of occupational lung disease. The finding of large numbers of pottery workers exposed to unacceptable dust concentrations is not surprising as poor dust control was found in all six wall tile and sanitary ware factories surveyed by the National Centre for Occupational Health between 1973 and 1989. Dust related occupational disease can be expected in potters for many years to come.

  20. Peroxidase activity, soluble proteins and chlorophyll content in spruce (Picea abies L. Karst.) needles affected by cement dust

    OpenAIRE

    Cesar, Vera; Lepeduš, Hrvoje

    2001-01-01

    The correlation between the peroxidase activity, chlorophyll and soluble protein content as well as the changes in vascular bundle structure in Norway spruce (Picea abies L. Karst.) needles affected by cement dust were studied. In spite of the absence of any yellowing symptoms, a significantly lower chlorophyll content was measured in spruce needles affected by cement dust. Observed sieve cells distortions in needle samples indicated that spruce trees grown near the cement factory were Mg def...

  1. Technogenic Magnetic Particles in Alkaline Dusts from Power and Cement Plants

    OpenAIRE

    2012-01-01

    During this study, we investigated the mineralogical characterization of technogenic magnetic particles (TMPs) contained in alkaline industrial dust and fly ash emitted by coal burning power plants and cement plants. The reaction of tested dust samples varied between values of pH 8 and pH 12. Their magnetic properties were characterized by measurement of magnetic susceptibility (χ), frequency dependence of magnetic susceptibility (χfd), and temperature dependence of magnetic susceptibility. M...

  2. Dust exposure in indoor climbing halls.

    Science.gov (United States)

    Weinbruch, Stephan; Dirsch, Thomas; Ebert, Martin; Hofmann, Heiko; Kandler, Konrad

    2008-05-01

    The use of hydrated magnesium carbonate hydroxide (magnesia alba) for drying the hands is a strong source for particulate matter in indoor climbing halls. Particle mass concentrations (PM10, PM2.5 and PM1) were measured with an optical particle counter in 9 indoor climbing halls and in 5 sports halls. Mean values for PM10 in indoor climbing halls are generally on the order of 200-500 microg m(-3). For periods of high activity, which last for several hours, PM10 values between 1000 and 4000 microg m(-3) were observed. PM(2.5) is on the order of 30-100 microg m(-3) and reaches values up to 500 microg m(-3), if many users are present. In sports halls, the mass concentrations are usually much lower (PM10 sport in which magnesia alba is also used) similar dust concentrations as for indoor climbing were observed. The size distribution and the total particle number concentration (3.7 nm-10 microm electrical mobility diameter) were determined in one climbing hall by an electrical aerosol spectrometer. The highest number concentrations were between 8000 and 12 000 cm(-3), indicating that the use of magnesia alba is no strong source for ultrafine particles. Scanning electron microscopy and energy-dispersive X-ray microanalysis revealed that virtually all particles are hydrated magnesium carbonate hydroxide. In-situ experiments in an environmental scanning electron microscope showed that the particles do not dissolve at relative humidities up to 100%. Thus, it is concluded that solid particles of magnesia alba are airborne and have the potential to deposit in the human respiratory tract. The particle mass concentrations in indoor climbing halls are much higher than those reported for schools and reach, in many cases, levels which are observed for industrial occupations. The observed dust concentrations are below the current occupational exposure limits in Germany of 3 and 10 mg m(-3) for respirable and inhalable dust. However, the dust concentrations exceed the German guide

  3. Lime kiln dust as a potential raw material in portland cement manufacturing

    Science.gov (United States)

    Miller, M. Michael; Callaghan, Robert M.

    2004-01-01

    In the United States, the manufacture of portland cement involves burning in a rotary kiln a finely ground proportional mix of raw materials. The raw material mix provides the required chemical combination of calcium, silicon, aluminum, iron, and small amounts of other ingredients. The majority of calcium is supplied in the form of calcium carbonate usually from limestone. Other sources including waste materials or byproducts from other industries can be used to supply calcium (or lime, CaO), provided they have sufficiently high CaO content, have low magnesia content (less than 5 percent), and are competitive with limestone in terms of cost and adequacy of supply. In the United States, the lime industry produces large amounts of lime kiln dust (LKD), which is collected by dust control systems. This LKD may be a supplemental source of calcium for cement plants, if the lime and cement plants are located near enough to each other to make the arrangement economical.

  4. Analysis of Potentially Toxic Metals in Airborne Cement Dust Around Sagamu, Southwestern Nigeria

    Science.gov (United States)

    Gbadebo, A. M.; Bankole, O. D.

    This study analyzed the concentration levels of potentially toxic and harmful elements contained in the airborne cement dust generated in the vicinity and farther away 500 m in the conventional four cardinal directions from the West African Portland Cement Company (WAPCO) factory mill, Sagamu. The results indicated that the concentration range of these toxic elements fall between 40.0 and 280,000 μg g-1 in the cement dust samples. Also, the concentration range of these toxic elements in 1 L of air samples varies between 0.01 μg g-1 and 29.92 μg L-1. The results generally show elevated concentrations of all the elements when compared with USA threshold limit of particulate mental concentration (e.g., Pb (1.5 g m-3); Cd (0.004-0.026 g m-3) in the air. These elements in the airborne cement dusts may pose a great threat to the health of plants, animals and residents in and around the factory and also to workers and visitors to the factory.

  5. Characterization of vapor phase mercury released from concrete processing with baghouse filter dust added cement.

    Science.gov (United States)

    Wang, Jun; Hayes, Josh; Wu, Chang-Yu; Townsend, Timothy; Schert, John; Vinson, Tim; Deliz, Katherine; Bonzongo, Jean-Claude

    2014-02-18

    The fate of mercury (Hg) in cement processing and products has drawn intense attention due to its contribution to the ambient emission inventory. Feeding Hg-loaded coal fly ash to the cement kiln introduces additional Hg into the kiln's baghouse filter dust (BFD), and the practice of replacing 5% of cement with the Hg-loaded BFD by cement plants has recently raised environmental and occupational health concerns. The objective of this study was to determine Hg concentration and speciation in BFD as well as to investigate the release of vapor phase Hg from storing and processing BFD-added cement. The results showed that Hg content in the BFD from different seasons ranged from 0.91-1.44 mg/kg (ppm), with 62-73% as soluble inorganic Hg, while Hg in the other concrete constituents were 1-3 orders of magnitude lower than the BFD. Up to 21% of Hg loss was observed in the time-series study while storing the BFD in the open environment by the end of the seventh day. Real-time monitoring in the bench system indicated that high temperature and moisture can facilitate Hg release at the early stage. Ontario Hydro (OH) traps showed that total Hg emission from BFD is dictated by the air exchange surface area. In the bench simulation of concrete processing, only 0.4-0.5% of Hg escaped from mixing and curing BFD-added cement. A follow-up headspace study did not detect Hg release in the following 7 days. In summary, replacing 5% of cement with the BFD investigated in this study has minimal occupational health concerns for concrete workers, and proper storing and mixing of BFD with cement can minimize Hg emission burden for the cement plant.

  6. Technogenic Magnetic Particles in Alkaline Dusts from Power and Cement Plants.

    Science.gov (United States)

    Magiera, Tadeusz; Gołuchowska, Beata; Jabłońska, Mariola

    2013-01-01

    During this study, we investigated the mineralogical characterization of technogenic magnetic particles (TMPs) contained in alkaline industrial dust and fly ash emitted by coal burning power plants and cement plants. The reaction of tested dust samples varied between values of pH 8 and pH 12. Their magnetic properties were characterized by measurement of magnetic susceptibility (χ), frequency dependence of magnetic susceptibility (χ(fd)), and temperature dependence of magnetic susceptibility. Mineralogical and geochemical analyses included scanning electron microscopy with energy dispersive spectroscopy, microprobe analysis and X-ray diffraction. The TMPs in fly ash from hard coal combustion have the form of typical magnetic spherules with a smooth or corrugated surface as well as a skeletal morphology, composed of iron oxides (magnetite, maghemite, and magnesioferrite) that occurred in the form of incrustation on the surface of mullite, amorphous silica, or aluminosilicate particles. The TMPs observed in fly ash from lignite combustion have a similar morphological form but a different mineralogical composition. Instead of magnetite and magnesioferrite, maghemite and hematite with lower χ values were the prevailing magnetic minerals, which explains the much lower magnetic susceptibility of this kind of ash in comparison with the ash from hard coal combustion, and probably results from the lower temperature of lignite combustion. Morphology and mineralogical composition of TMPs in cement dust is more diverse. The magnetic fraction of cement dust occurs mostly in the form of angular and octahedral grains of a significantly finer granulation (cement dust is calcium ferrite (CaFe(3)O(5)). The greatest impact on the magnetic susceptibility of cement dust results from iron-bearing additives (often waste materials from other branches of industry), which should be considered the most dangerous to the environment. Stoichiometric analysis of micro-particles confirmed

  7. Effects of cement flue dust from a cement factory on stress parameters and diversity of aquatic plants.

    Science.gov (United States)

    Erdal, Serkan; Demirtas, Ayten

    2010-07-01

    Cement kiln dusts, made of a complex mixture of elements, include high levels of heavy metals such as fluoride, magnesium, lead, cadmium, nickel, zinc, copper, beryllium and some toxic compounds. Because of the toxic element compositions and radioactive isotope properties of cement kiln dusts, not only terrestrial but also aquatic ecosystems are subjected to greater stress. In the present paper, we investigated the effects of pollution caused by Askale-Erzurum cement factory (CF) on the stress parameters and diversity of aquatic plants. For this purpose, aquatic plant species were collected from the outer zone of the CF. Only three (Lemna minor, Ceratophyllum submersum and Potamogeton natans) of these species were able to be determined in the CF zone. Antioxidant enzyme activities of the collected aquatic plants were measured and compared to their controls. Superoxide dismutase (SOD) activity of P. natans in the CF zone was significantly high compared to their respective control, while it was low in L. minor and C. submersum compared to their controls. Similarly, peroxidase (POX) activity of P. natans was high, while those of L. minor and C. submersum were low compared to their respective controls. On the other side, while catalase (CAT) activities of L. minor and C. submersum were low, that of P. natans did not show an important change compared to their respective controls. Furthermore, we found that hydrogen peroxide (H(2)O(2)) and malondialdehyde (MDA) levels of all the studied plants were also very high compared to their controls. According to these results, it is clear that pollution caused by the CF reduced diversity and number of aquatic plant species. Besides, the obtained data revealed that P. natans have a more resistant defense system than other species.

  8. Partial Replacement of Cement with Marble Dust Powder

    OpenAIRE

    Ranjan Kumar; Shyam Kishor Kuma

    2015-01-01

    The waste generated from the industries cause environmental problems. Hence the reuse of this waste material can be emphasized. MarbleDust Powder (MDP) is a developing composite materialthatwillallow the concrèteindustry to optimisemateriel use, generateeconomicbenefits and build structures thatwillstrong, durable and sensitive to environnement. MDP is by-product obtained during the quarrying process from the parent marble rock; which contains high calcium oxide content of more th...

  9. Experimental study of the mechanical stabilization of electric arc furnace dust using fluid cement mortars.

    Science.gov (United States)

    Ledesma, E F; Jiménez, J R; Ayuso, J; Fernández, J M; Brito, J de

    2017-03-15

    This article shows the results of an experimental study carried out in order to determine the maximum amount of electric arc furnace dust (EAFD) that can be incorporated into fluid cement-based mortars to produce mechanically stable monolithic blocks. The leaching performance of all mixes was studied in order to classify them according to the EU Council Decision 2003/33/EC. Two mortars were used as reference and three levels of EAFD incorporation were tested in each of the reference mortars. As the incorporation ratio of EAFD/cement increases, the mechanical strength decreases. This is due to the greater EAFD/cement and water/cement ratios, besides the presence of a double-hydrated hydroxide of Ca and Zn (CaZn2(OH)6·2H2O) instead of the portlandite phase (Ca(OH)2) in the mixes made with EAFD, as well as non-hydrated tricalcium silicate. A mass ratio of 2:1 (EAFD: cement-based mortar) can be added maintaining a stable mechanical strength. The mechanical stabilization process also reduced the leaching of metals, although it was not able to reduce the Pb concentration below the limit for hazardous waste. The high amount of EAFD mechanically stabilized in this experimental study can be useful to reduce the storage volume required in hazardous waste landfills.

  10. Feedback on Measured Dust Concentrations Reduces Exposure Levels among Farmers

    NARCIS (Netherlands)

    Basinas, Ioannis; Sigsgaard, Torben; B??nl??kke, Jakob Hjort; Andersen, Nils Testrup; Omland, ??yvind; Kromhout, Hans; Schl??nssen, Vivi

    2016-01-01

    Background: 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 obj

  11. Wood-related occupations, wood dust exposure, and sinonasal cancer.

    Science.gov (United States)

    Hayes, R B; Gerin, M; Raatgever, J W; de Bruyn, A

    1986-10-01

    A case-control study was conducted to examine the relations between type of woodworking and the extent of wood dust exposure to the risks for specific histologic types of sinonasal cancer. In cooperation with the major treatment centers in the Netherlands, 116 male patients newly diagnosed between 1978 and 1981 with primary malignancies of epithelial origin of this site were identified for study. Living controls were selected from the municipal registries, and deceased controls were selected from the national death registry. Interviews were completed for 91 (78%) cases and 195 (75%) controls. Job histories were coded by industry and occupation. An index of exposure was developed to classify the extent of occupational exposure to wood dust. When necessary, adjustment was made for age and usual cigarette use. The risk for nasal adenocarcinoma was elevated by industry for the wood and paper industry (odds ratio (OR) = 11.9) and by occupation for those employed in furniture and cabinet making (OR = 139.8), in factory joinery and carpentry work (OR = 16.3), and in association with high-level wood dust exposure (OR = 26.3). Other types of nasal cancer were not found to be associated with wood-related industries or occupations. A moderate excess in risk for squamous cell cancer (OR = 2.5) was associated with low-level wood dust exposure; however, no dose-response relation was evident. The association between wood dust and adenocarcinoma was strongest for those employed in wood dust-related occupations between 1930 and 1941. The risk of adenocarcinoma did not appear to decrease for at least 15 years after termination of exposure to wood dust. No cases of nasal adenocarcinoma were observed in men whose first exposure to wood dust occurred after 1941.

  12. Determinants of wood dust exposure in the Danish furniture industry.

    Science.gov (United States)

    Mikkelsen, Anders B; Schlunssen, Vivi; Sigsgaard, Torben; Schaumburg, Inger

    2002-11-01

    This paper investigates the relation between wood dust exposure in the furniture industry and occupational hygiene variables. During the winter 1997-98 54 factories were visited and 2362 personal, passive inhalable dust samples were obtained; the geometric mean was 0.95 mg/m(3) and the geometric standard deviation was 2.08. In a first measuring round 1685 dust concentrations were obtained. For some of the workers repeated measurements were carried out 1 (351) and 2 weeks (326) after the first measurement. Hygiene variables like job, exhaust ventilation, cleaning procedures, etc., were documented. A multivariate analysis based on mixed effects models was used with hygiene variables being fixed effects and worker, machine, department and factory being random effects. A modified stepwise strategy of model making was adopted taking into account the hierarchically structured variables and making possible the exclusion of non-influential random as well as fixed effects. For woodworking, the following determinants of exposure increase the dust concentration: manual and automatic sanding and use of compressed air with fully automatic and semi-automatic machines and for cleaning of work pieces. Decreased dust exposure resulted from the use of compressed air with manual machines, working at fully automatic or semi-automatic machines, functioning exhaust ventilation, work on the night shift, daily cleaning of rooms, cleaning of work pieces with a brush, vacuum cleaning of machines, supplementary fresh air intake and safety representative elected within the last 2 yr. For handling and assembling, increased exposure results from work at automatic machines and presence of wood dust on the workpieces. Work on the evening shift, supplementary fresh air intake, work in a chair factory and special cleaning staff produced decreased exposure to wood dust. The implications of the results for the prevention of wood dust exposure are discussed.

  13. Physicochemical characterization of cement kiln dust for potential reuse in acidic wastewater treatment

    Energy Technology Data Exchange (ETDEWEB)

    Mackie, A.; Boilard, S. [Department of Civil and Resource Engineering, Dalhousie University, 1360 Barrington St., Building D, Room D215, Halifax, Nova Scotia, B3J 1Z1 (Canada); Walsh, M.E., E-mail: mwalsh2@dal.ca [Department of Civil and Resource Engineering, Dalhousie University, 1360 Barrington St., Building D, Room D215, Halifax, Nova Scotia, B3J 1Z1 (Canada); Lake, C.B. [Department of Civil and Resource Engineering, Dalhousie University, 1360 Barrington St., Building D, Room D215, Halifax, Nova Scotia, B3J 1Z1 (Canada)

    2010-01-15

    Cement kiln dust (CKD) is a fine-grained material produced during the manufacture of cement. Current reuse options are limited and the bulk of CKD not reused in the cement manufacturing process is sent to landfills or stored on-site. Due to the calcium oxide (CaO) content of CKD, it has the potential to be used as a replacement for lime in treating acidic wastewaters such as acid rock drainage (ARD). This paper outlines the results of an examination of the physical and chemical properties of CKD samples collected from six cement plants. The CKD samples were analyzed for major oxides using X-ray diffraction (XRD), available lime, specific surface area, particle size, and morphology using scanning electron microscope (SEM) and compared with a commercial quicklime product. Conductivity, pH, and calcium concentrations of slaked CKD and quicklime solutions were used as indicators of reactivity of the CKD. Slaking of two of the CKD samples with the highest free lime contents (e.g., 34 and 37% free CaO) gave elevated pH values statistically comparable to those of the commercial quicklime sample that was characterized as having 87% available CaO. Acid neutralization trials indicate that even CKD samples with low free lime contents could be effective at neutralizing acidic wastewaters.

  14. Physicochemical characterization of cement kiln dust for potential reuse in acidic wastewater treatment.

    Science.gov (United States)

    Mackie, A; Boilard, S; Walsh, M E; Lake, C B

    2010-01-15

    Cement kiln dust (CKD) is a fine-grained material produced during the manufacture of cement. Current reuse options are limited and the bulk of CKD not reused in the cement manufacturing process is sent to landfills or stored on-site. Due to the calcium oxide (CaO) content of CKD, it has the potential to be used as a replacement for lime in treating acidic wastewaters such as acid rock drainage (ARD). This paper outlines the results of an examination of the physical and chemical properties of CKD samples collected from six cement plants. The CKD samples were analyzed for major oxides using X-ray diffraction (XRD), available lime, specific surface area, particle size, and morphology using scanning electron microscope (SEM) and compared with a commercial quicklime product. Conductivity, pH, and calcium concentrations of slaked CKD and quicklime solutions were used as indicators of reactivity of the CKD. Slaking of two of the CKD samples with the highest free lime contents (e.g., 34 and 37% free CaO) gave elevated pH values statistically comparable to those of the commercial quicklime sample that was characterized as having 87% available CaO. Acid neutralization trials indicate that even CKD samples with low free lime contents could be effective at neutralizing acidic wastewaters.

  15. Steel foundry electric arc furnace dust management: stabilization by using lime and Portland cement.

    Science.gov (United States)

    Salihoglu, Guray; Pinarli, Vedat

    2008-05-30

    The purpose of this study was to determine an appropriate treatment for steel foundry electric arc furnace dust (EAFD) prior to permanent disposal. Lime and Portland cement (PC)-based stabilization was applied to treat the EAFD that contains lead and zinc above the landfilling limits, and is listed by USEPA as hazardous waste designation K061 and by EU as 10 02 07. Three types of paste samples were prepared with EAFD content varying between 0 and 90%. The first type contained the EAFD and Portland cement, the second contained the EAFD, Portland cement, and lime, and the third contained the EAFD and lime. All the samples were subjected to toxicity characteristics leaching procedure (TCLP) after an air-curing period of 28 days. pH changes were monitored and acid neutralization capacity of the samples were examined. Treatment effectiveness was evaluated in terms of reducing the heavy metal leachability to the levels below the USEPA landfilling criteria. An optimum composition for the EAFD stabilization was formulated as 30% EAFD +35% lime +35% Portland cement to achieve the landfilling criteria. The pH interval, where the solubility of the heavy metals in the EAFD was minimized, was found to be between 8.2 and 9.4.

  16. Silica dust exposure: Effect of filter size to compliance determination

    Science.gov (United States)

    Amran, Suhaily; Latif, Mohd Talib; Khan, Md Firoz; Leman, Abdul Mutalib; Goh, Eric; Jaafar, Shoffian Amin

    2016-11-01

    Monitoring of respirable dust was performed using a set of integrated sampling system consisting of sampling pump attached with filter media and separating device such as cyclone or special cassette. Based on selected method, filter sizes are either 25 mm or 37 mm poly vinyl chloride (PVC) filter. The aim of this study was to compare performance of two types of filter during personal respirable dust sampling for silica dust under field condition. The comparison strategy focused on the final compliance judgment based on both dataset. Eight hour parallel sampling of personal respirable dust exposure was performed among 30 crusher operators at six quarries. Each crusher operator was attached with parallel set of integrated sampling train containing either 25 mm or 37 mm PVC filter. Each set consisted of standard flow SKC sampler, attached with SKC GS3 cyclone and 2 pieces cassette loaded with 5.0 µm of PVC filter. Samples were analyzed by gravimetric technique. Personal respirable dust exposure between the two types of filters indicated significant positive correlation (p < 0.05) with moderate relationship (r2 = 0.6431). Personal exposure based on 25 mm PVC filter indicated 0.1% non-compliance to overall data while 37 mm PVC filter indicated similar findings at 0.4 %. Both data showed similar arithmetic mean(AM) and geometric mean(GM). In overall we concluded that personal respirable dust exposure either based on 25mm or 37mm PVC filter will give similar compliance determination. Both filters are reliable to be used in respirable dust monitoring for silica dust related exposure.

  17. Physicochemical and microbiological characterization of cement kiln dust for potential reuse in wastewater treatment.

    Science.gov (United States)

    Salem, W M; Sayed, W F; Halawy, S A; Elamary, R B

    2015-09-01

    Cement kiln dust (CKD), a byproduct of cement manufacturing process, was collected from Misr Cement Co. at Qena, Egypt. CKD was characterized by X-ray diffraction and FTIR analysis. This byproduct was investigated for its physical-chemical characters, antibacterial activities on sewage water and the presence of nematode, parasites and algae in the treated water. The efficiency of CKD-treated water was also examined on Hibiscus sabdarriffa seed germination. Total bacteria, total and fecal coliform, as well as fecal streptococci were completely inhibited by CKD. Interestingly, zinc, manganese, iron, nickel and lead were completely absent from sewage water as these metals precipitated after treatment with 10gl(-1) CKD. On the other hand, among all the tested plant criteria, only root length was significantly reduced by 55% and 15% after zero and 3 days of CKD addition respectively compared to control. Furthermore, plant lipid peroxidation showed no significant differences between treated sewage water and control after zero and 3 days time addition of CKD. Catalase enzyme activity showed significant decrease by 56% and 64%, while peroxidase activity significantly increased up to 49% and 63% compared to untreated sewage after zero and 3 days of treatment, respectively. The absorption of lead, iron and copper by treated and untreated plants showed no significant differences. Chromium ions were highly absorbed (0.075mgl(-1)) by plants irrigated only with treated sewage water at zero time, and decreased gradually to 0.018mgl(-1) after 3 days of CKD addition. This study highlighted the efficiency of cement kiln dust as an antibacterial agent and its ability of scavenging heavy metals leading to the use of treated sewage water in activities such as crop irrigation.

  18. Emphysema and dust exposure in a group of coal workers

    Energy Technology Data Exchange (ETDEWEB)

    Ruckley, V.A.; Gauld, S.J.; Chapman, J.S.; Davis, J.M.; Douglas, A.N.; Fernie, J.M.; Jacobsen, M.; Lamb, D.

    1984-04-01

    The lungs of 450 coal miners who had been studied previously in a long-term epidemiologic project at 24 British mines have been examined post-mortem for signs of dust-related fibrosis and emphysema. Reliable estimates of cumulative (working-life) exposures to respirable mine dust were available for 342 of the men. The relative frequency of emphysema increased with age at death, and both panacinar and centriacinar emphysema occurred more frequently in smokers than in nonsmokers. The proportion of subjects with any emphysema was 47% in 92 men with no palpable dust lesions, 65% in 183 with small, simple pneumoconiotic lesions, and 83% in 175 miners with massive fibrosis (PMF). The chance of finding centriacinar emphysema in those with PMF increased significantly with increasing exposure to coal dust in life (p less than 0.025). A similar but less convincing relationship was found in those with simple pneumoconiosis (p less than 0.11), but in both groups, increasing amounts of ash with a given exposure to coal reduced the probability of finding centriacinar emphysema. The occurrence of centriacinar emphysema was associated also with increasing amounts of dust retained in the lungs. A preliminary exploration of this association did not support the hypothesis that emphysematous lungs clear dust less efficiently. We conclude that the association observed between exposure to respirable coal dust and emphysema in coal miners indicates a causal relationship. However, because it can be demonstrated only for men whose lungs show some dust-related fibrosis, it is suggested that the extent and nature of such fibrosis may be a crucial factor in determining the presence of centriacinar emphysema.

  19. Dust extraction from gas in cement kilns, using bag filters; Depoussierage des gaz de four cimentier par les filtres a manches

    Energy Technology Data Exchange (ETDEWEB)

    Harmegnies, M. [CALCIA, 78 - Guerville (France). Direction Technique

    1996-12-31

    After a review of regulations concerning cement plant emissions, the two main cement production techniques (dry and semi-dry processes) are described and the electrostatic and bag filter de-dusting techniques are compared. Examples of pilot applications of these techniques in two French cement plants are presented and operating results (performances, transient procedures, costs) are discussed

  20. Properties of steel foundry electric arc furnace dust solidified/stabilized with Portland cement.

    Science.gov (United States)

    Salihoglu, Guray; Pinarli, Vedat; Salihoglu, Nezih Kamil; Karaca, Gizem

    2007-10-01

    Electric arc furnace dust from steel production is generated in considerable amounts worldwide and needs to be treated as hazardous waste. The aim of this study was to investigate the properties of electric arc furnace dust solidified/stabilized by using Portland cement. Mortar and paste samples were prepared with varying waste-to-binder ratios between 0% and 90%. A comprehensive experimental program was designed including XRF characterization, setting time, unconfined compressive strength, and toxicity characteristics leaching procedure (TCLP), synthetic precipitation leaching procedure (SPLP), and acid neutralization capacity (ANC) tests. The results were evaluated in order to determine if the solidified /stabilized product can be disposed of at a landfill site with domestic waste or at a segregated landfill. The effect of using sand on S/S performance was also investigated. The results indicated that the solidification /stabilization process using PC helps the heavy metals to be bound in the cement matrix, but the TCLP leaching results exceeded the EPA landfilling limits. The SPLP leaching results conformed to the limits implying that the waste or S/S products can be disposed of at a segregated landfill; however the low ANC of the S/S products reveals that there may be leaching in the long-term. The sand used in the mortar samples adversely affected the S/S performance, causing higher heavy metal leaching levels, and lower pH levels in the leachate after the TCLP extraction than those measured in the leachate of the paste samples.

  1. [Evaluation of exposure of workers to asbestos dust in asbestos-processing plants].

    Science.gov (United States)

    Stroszejn-Mrowca, G; Wiecek, E

    1985-01-01

    Working environments have been tested in plants producing asbestos products, asbestos-cement products, textile asbestos products, asbestos-caoutchouc plates, asbestos boards and asbestos frictional materials for automotive industry, Measurements of total dust concentrations and concentrations of asbestos fibres 5 micron long supported workers' exposure investigations. Basing on literature data on the working environment at the Mining Metallurgical Plant in Szklary, the health risk for workers producing nickel from ores containing asbestos mixtures has been analysed. The asbestos-exposure in asbestos-processing plants has been found to be still considerable despite modernization of the plants. Particularly dangerous to health have been regarded the conditions at asbestos spinning-mills and the Mining-Metallurgical Plant at Szklary, where even average asbestos concentrations considerably exceed the threshold limit values.

  2. Wood dust exposure in wood industry and forestry.

    Science.gov (United States)

    Puntarić, Dinko; Kos, Ankica; Smit, Zdenko; Zecić, Zeljko; Sega, Kresimir; Beljo-Lucić, Ruzica; Horvat, Dubravko; Bosnir, Jasna

    2005-06-01

    The aim of the study was to determine occupational exposure in Croatian wood processing industry and forest workers to harmful effects of wood dust on the risk of nose, nasal cavity and lung carcinoma. Mass concentrations of respirable particles and total wood dust were measured at two wood processing plants, three woodwork shops, and one lumbering site, where 225 total wood dust samples and 221 respirable particle samples were collected. Wood dust mass concentration was determined by the gravimetric method. Mass concentrations exceeding total wood dust maximal allowed concentration (MAC, 3 mg/m3) were measured for beechwood and oakwood dust in 38% (79/206) of study samples from wood processing facilities (plants and woodwork shops). Mass concentrations of respirable particles exceeding MAC (1 mg/m3) were recorded in 24% (48/202) of samples from wood processing facilities (mean 2.38 +/- 2.08 mg/m3 in plants and 3.6 +/- 2.22 mg/m3 in woodwork shops). Thus, 13% (27/206) of work sites in wood processing facilities failed to meet health criteria according to European guidelines. Launching of measures to reduce wood dust emission to the work area is recommended.

  3. Wood dust exposure in the Danish furniture industry using conventional and passive monitors.

    Science.gov (United States)

    Schlünssen, V; Vinzents, P S; Mikkelsen, A B; Schaumburg, I

    2001-03-01

    A study of wood dust exposure at furniture factories in one county in Denmark was performed as a cross sectional study. Dust exposure was measured with personal passive dust monitors and calibrated against active sampling on filters. Measurements of 1685 workers were included in the exposure assessment. The passive dust monitor conversion models for equivalent concentrations of inhalable dust and total dust based on data from the present study were not significantly different from the original models. Therefore models based on all available data were used. The parameters of the distribution of equivalent concentration of inhalable dust were 0.94 mg/m3 (geometric mean) and 2.10 (geometric standard deviation). Compared with a national cross sectional study from 1988 the exposure level (geometric mean) was reduced by a factor 2.0. Inhalable dust exposure was about 50% higher than exposure measured by the Danish 'total' dust method.

  4. Assessing Metal Exposures in a Community near a Cement Plant in the Northeast U.S.

    OpenAIRE

    2015-01-01

    Cement production is a major source of metals and metalloids in the environment, while exposures to metals and metalloids may impact human health in the surrounding communities. We recruited 185 participants living in the vicinity of a cement plant in the northeast U.S., and measured the levels of aluminum (Al), arsenic (As), cadmium (Cd), lead (Pb), mercury (Hg), and selenium (Se) in blood and Hg in hair samples from them. A questionnaire was used to assess potential sources of Hg exposure...

  5. EXPOSURE TO SWINE HOUSING DUST MODULATES MACROPHAGE MORPHOLOGY AND FUNCTION

    Directory of Open Access Journals (Sweden)

    Ruth J. Pender

    2014-01-01

    Full Text Available Swine Confinement Facility (SCF dust consists of a complex mixture of feed grain particles, bacterial components, organic particulates and gases. When these particles are inhaled they deposit along the respiratory tract and mediate respiratory symptoms and disease in swine farmers and facility workers. Macrophages ingest and eliminate microbes and debris under chronic conditions; however, the role of macrophages in agricultural-related respiratory disease has not been fully elucidated. The goal was to evaluate the hypothesis that chronic exposure to SCF dust causes inflammation by modulating pulmonary protein levels and macrophage function. Balb/c mice were exposed to 5, 12.5 and 25% SCF Dust Extract (DE via nebulization 30 min/day five days a week, for eight weeks with weekends excluded. Bronchoalveolar Lavage Fluid (BALF was collected and analyzed for protein concentration, leukocyte distribution and macrophage morphology. For comparison, THP-1 monocytic cells were exposed to 0.1-10% DE overnight and evaluated for phagocytosis and reactive oxygen species production. Repeated exposure to DE via nebulizer caused a significant increase in protein concentration and inflammatory cell number, namely macrophages, in a dose-dependent manner within the lung as compared to controls. Macrophages with pseudopods and vacuoles were the most abundant leukocytes within BALF of mice exposed to DE. Similarly, in vitro studies with 10% DE treated THP-1 cells revealed enhanced phagocytosis (p<0.05, pseudopodia and vacuolization following exposure to compared to control cells. In addition, there were time- and dose-dependent increases of intracellular ROS production by THP-1 cells exposed to 5 and 10% DE compared to control (p<0.01. These findings indicate repeated, long-term inhalation of swine confinement facility dust may mediate chronic airway and lung inflammation through modulation of protein concentration and macrophage function. The aerosolized dust

  6. [Occupational exposure to wood dust. Health effects and exposure limit values].

    Science.gov (United States)

    Carton, M; Goldberg, M; Luce, D

    2002-04-01

    This article presents a review of the health effects of occupational exposure to wood dusts and of the data that could be used for setting occupational exposure limits for this nuisance. The causal role of wood dust in the onset of sinonasal cancers is solidly established by numerous epidemiological studies, and the magnitude of the risk is particularly high for adenocarcinoma induced by exposure to hardwood dust. However, no current data allows to rule out the carcinogenic role of softwood dusts and, in the view of protecting the health of the workers, it does not seem relevant to distinguish these two types of wood. Various impairments of the lung function have been frequently associated with exposure to both 'allergenic' and 'non-allergenic' wood dusts and may occur at very low concentrations. According to the SUMER 94 and CAREX studies, about 200 000 workers are currently exposed to wood dusts in France (about 1% of the working population between 1990 and 1994). When taking into account full professional careers, the percentage of workers having been occupationally exposed can be estimated to be about 15% for men and 5% for women. Measurements performed in France between 1987 and 2000 show that exposure levels are high, about 50% of the samplings being over 1mg/m(3) (actual TWA in France). Although the studies present limits, particularly for the quantitative assessment of individual exposure levels, it seems that nonmalignant effects are susceptible to arise at the level of 1mg/m(3); a limit value of 0.5mg/m(3) would credibly allow to protect exposed workers from most of the risks of nonmalignant pulmonary effects. However, it is impossible to assure that this value will avoid the induction of sinonasal cancer, even if this level is certainly lower than the levels to which the cases of sinonasal cancers published in the literature were exposed.

  7. Phytoextraction of chloride from a cement kiln dust (CKD) contaminated landfill with Phragmites australis.

    Science.gov (United States)

    McSorley, Kaitlin; Rutter, Allison; Cumming, Robert; Zeeb, Barbara A

    2016-05-01

    Cement kiln dust (CKD) is a globally produced by-product from cement manufacturing that is stockpiled or landfilled. Elevated concentrations of chloride pose toxic threats to plants and aquatic communities, as the anion is highly mobile in water and can leach into surrounding water sources. Re-vegetation and in situ phytoextraction of chloride from a CKD landfill in Bath, ON, Canada, was investigated with the resident invasive species Phragmites australis (haplotype M). Existing stands of P. australis were transplanted from the perimeter of the site into the highest areas of contamination (5.9×10(3)μg/g). Accumulation in the shoots of P. australis was quantified over one growing season by collecting samples from the site on a bi-weekly basis and analyzing for chloride. Concentrations decreased significantly from early May (24±2.2×10(3)μg/g) until mid-June (15±2.5×10(3)μg/g), and then remained stable from June to August. Shoot chloride accumulation was not significantly affected by water level fluctuations at the site, however elevated potassium concentrations in the soil may have contributed to uptake. Based on shoot chloride accumulation and total biomass, it was determined that phytoextraction from the CKD landfill can remove 65±4kg/km(2) of chloride per season. Based on this extraction rate, removal of chloride present in the highly contaminated top 10cm of soil can be achieved in 3-9years. This is the first study to apply phytotechnologies at a CKD landfill, and to successfully demonstrate in situ phytoextraction of chloride.

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

    Science.gov (United States)

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

    1993-10-01

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

  9. Assessing metal exposures in a community near a cement plant in the Northeast U.S.

    Science.gov (United States)

    Dong, Zhao; Bank, Michael S; Spengler, John D

    2015-01-19

    Cement production is a major source of metals and metalloids in the environment, while exposures to metals and metalloids may impact human health in the surrounding communities. We recruited 185 participants living in the vicinity of a cement plant in the northeast U.S., and measured the levels of aluminum (Al), arsenic (As), cadmium (Cd), lead (Pb), mercury (Hg), and selenium (Se) in blood and Hg in hair samples from them. A questionnaire was used to assess potential sources of Hg exposure. Multivariate regressions and spatial analyses were performed to evaluate the relative importance of different routes of exposures. The metal concentrations in blood or hair samples of our study participants were comparable to the U.S. general or regional population. Smoking contributed significantly to Cd and Pb exposures, and seafood consumption contributed significantly to Hg and As exposures, while variables related to the cement plant were not significantly associated with metal concentrations. Our results suggest that our study population was not at elevated health risk due to metal exposures, and that the contribution of the cement plant to metal exposures in the surrounding community was minimal.

  10. Cotton dust exposure: Analysis of pulmonary function and respiratory symptoms

    Directory of Open Access Journals (Sweden)

    Bharat M Dangi

    2017-01-01

    Full Text Available Background: Cotton industry workers are exposed to various hazards in the different departments of textile factories. The major health problems associated with cotton dust are respiratory problems, byssinosis, bronchitis and asthma. Objective: To study the effect of cotton dust exposure on pulmonary function and respiratory symptoms. Settings and Design: This cross-sectional observational study was conducted at cotton mill in the Ahmedabad city. Materials and Methods: One hundred cotton mill workers of the weaving and spinning area participated in this study while 100 age- and gender-matched male subjects living in the residential area served as the control group. A questionnaire was used to inquire about respiratory symptoms and spirometry was done in both the groups. Statistical Analysis Used: Student's t-test was used to find the difference between spirometric parameters, and Chi-square test was used to find the difference between respiratory symptoms. Results: Respiratory symptoms were statistically significantly more common in the cotton mill workers compared to control group. Cotton mill workers group also showed significant (P < 0.0001 decrease in forced expiratory volume in 1 s (FEV1, ratio of FEV1 and forced vital capacity (FVC and peak expiratory flow rate, and no significant difference of FVC between groups. There was an association of duration of exposure and symptoms with spirometric abnormality. Conclusion: Cotton mill workers showed a significant decrease in spirometric parameters and increase in respiratory symptoms. As the duration of exposure and symptoms increased, spirometric abnormality increased.

  11. Assessment of bioaerosols and inhalable dust exposure in Swiss sawmills.

    Science.gov (United States)

    Oppliger, Anne; Rusca, Sophie; Charrière, Nicole; Vu Duc, Trinh; Droz, Pierre-Olivier

    2005-07-01

    An assessment of wood workers' exposure to airborne cultivable bacteria, fungi, inhalable endotoxins and inhalable organic dust was performed at 12 sawmills that process mainly coniferous wood species. In each plant, samples were collected at four or five different work sites (debarking, sawing, sorting, planing and sawing cockpit) and the efficiency of sampling devices (impinger or filter) for determining endotoxins levels was evaluated. Results show that fungi are present in very high concentrations (up to 35 000 CFU m(-3)) in all sawmills. We also find that there are more bioaerosols at the sorting work site (mean +/- SD: 7723 +/- 9919 CFU m(-3) for total bacteria, 614 +/- 902 CFU m(-3) for Gram-negative, 19 438 +/- 14 246 CFU m(-3) for fungi, 7.0 +/- 9.0 EU m(-3) for endotoxin and 2.9 +/- 4.8 g m(-3) for dust) than at the sawing station (mean +/- SD: 1938 +/- 2478 CFU m(-3) for total bacteria, 141 +/- 206 CFU m(-3) for Gram-negative, 12 207 +/- 10 008 CFU m(-3) for fungi, 2.1 +/- 1.9 EU m(-3) for endotoxin and 0.75 +/- 0.49 mg m(-3) for dust). At the same time, the species composition and concentration of airborne Gram-negative bacteria were studied. Penicillinium sp. were the predominant fungi, while Bacillus sp. and the Pseudomonadacea family were the predominant Gram-positive and Gram-negative bacteria encountered, respectively.

  12. The Lunar Environment: Determining the Health Effects of Exposure to Moon Dusts

    Science.gov (United States)

    Khan-Mayberry, Noreen

    2007-01-01

    The moon's surface is covered with a thin layer of fine, charged, reactive dust capable of layer of fine, charged, reactive dust capable of capable of entering habitats and vehicle compartments, where it can result in crewmember health problems. NASA formed the Lunar Airborne Dust Toxicity Advisory Group (LADTAG) to study the effects of exposure to Lunar Dust on human health. To date, no scientifically defensible toxicological studies have been performed on lunar dusts, specifically the determination of exposure limits and their affect on human health. The multi-center LADTAG (Lunar Airborne Dust Toxicology center LADTAG (Lunar Airborne Dust Toxicology Advisory Group) was formed in response to the Office of the Chief Health and Medical Office s (OCHMO) request to develop recommendations for defining risk (OCHMO) request to develop recommendations for defining risk defining risk criteria for human lunar dust exposure.

  13. Total and respirable dust exposures among carpenters and demolition workers during indoor work in Denmark

    DEFF Research Database (Denmark)

    Kirkeskov, Lilli; Hanskov, Dorte Jessing Agerby; Brauer, Charlotte

    2016-01-01

    or the variation between the different work tasks. The purpose of this study was therefore to assess if there were differences in dust exposure between carpenters and demolition workers who were expected to have low and high dust exposure, respectively. METHODS: Through interviews of key persons...... out for carpenters and 20 measurements of total dust, 11 of respirable dust and 11 of respirable crystalline silica dust on four different works tasks for demolition workers. Dust measurements were tested for differences using linear regression, t-test and one-way ANOVA. RESULTS: For carpenters...... deviation 11.6) and the respirable dust was 1.06 mg/m(3) (geometric standard deviation 5.64). The mean difference between total dust for demolition workers and carpenters was 11.4 (95 % confidence interval 3.46-37.1) mg/m(3). The mean difference between respirable dust for demolition workers and carpenters...

  14. Effects of composition and exposure on the solar reflectance of Portland cement concrete

    Energy Technology Data Exchange (ETDEWEB)

    Levinson, Ronnen; Akbari, Hashem

    2001-12-21

    Increasing the solar reflectance (albedo) of a paved surface keeps it cooler in the sun, reducing convection of heat from pavement to air and thereby decreasing the ambient air temperature. Simulations of the influence of pavement albedo on air temperature in Los Angeles predict that increasing the albedo of 1,250 km2 of pavement by 0.25 would save cooling energy worth $15M yr-1, and reduce smog-related medical and lost-work expenses by $76M yr-1. Most sidewalks and a small fraction of roads and parking areas are paved with portland cement concrete, which can be made quite reflective through suitable choice of cement and aggregate. Variations with composition and environmental exposure of the albedos of portland cement concrete pavements were investigated through laboratory fabrication and exposure of 32 mixes of concrete. Twenty-four mixes yielded substandard, ''rough'' concretes due to high, unmet aggregate water demand. The albedos of the remaining eight ''smooth'' concrete mixes ranged from 0.41 to 0.77 (mean 0.59). Simulated weathering, soiling, and abrasion each reduced average concrete albedo (mean decreases 0.06, 0.05, and 0.19, respectively), though some samples became slightly more reflective through weathering or soiling. Simulated rain (wetting) strongly depressed the albedos of concretes (mean decrease 0.23) until their surfaces were dried. Concrete albedo grew as the cement hydration reaction progressed (mean increase 0.08), but stabilized within six weeks of casting. White-cement concretes were on average significantly more reflective than gray-cement concretes. The albedo of the most-reflective white-cement concrete was 0.18 to 0.39 higher than that of the most-reflective gray-cement concrete, depending on state of exposure. Concrete albedo generally correlated with cement albedo and sand albedo, and, after abrasion, with rock albedo. Cement albedo had a disproportionately strong influence on the reflectance

  15. Longitudinal lung function decline and wood dust exposure in the furniture industry

    DEFF Research Database (Denmark)

    Jacobsen, G.; Schluenssen, V.; Schaumburg, I.

    2008-01-01

    The aim of the present study was to investigate the relationship between change in lung function and cumulative exposure to wood dust. In total, 1,112 woodworkers (927 males, 185 females) and 235 reference workers (104 males, 185 females) participated in a 6-yr longitudinal study. Forced expiratory...... volume in one second (FEV1), forced vital capacity (FVC), height and weight were measured, and questionnaire data on respiratory symptoms, wood dust exposure and smoking habits were collected. Cumulative inhalable wood dust exposure was assessed using a study-specific job exposure matrix and exposure...... time. The median (range) for cumulative wood dust exposure was 3.75 (0-7.55) mg.year.m(-3). A dose-response relationship between cumulative wood dust exposure and percent annual decrease in FEV1 was suggested for female workers. This was confirmed in a linear regression model adjusted for confounders...

  16. Longitudinal lung function decline and wood dust exposure in the furniture industry

    DEFF Research Database (Denmark)

    Jacobsen, Gitte; Schlünssen, V; Schaumburg, I

    2007-01-01

    The aim of the present study was to investigate the relationship between change in lung function and cumulative exposure to wood dust. In total, 1,112 woodworkers (927 males, 185 females) and 235 reference workers (104 males, 185 females) participated in a 6-yr longitudinal study. Forced expiratory...... volume in one second (FEV(1)), forced vital capacity (FVC), height and weight were measured, and questionnaire data on respiratory symptoms, wood dust exposure and smoking habits were collected. Cumulative inhalable wood dust exposure was assessed using a study-specific job exposure matrix and exposure...... time. The median (range) for cumulative wood dust exposure was 3.75 (0-7.55) mg x year x m(-3). A dose-response relationship between cumulative wood dust exposure and percent annual decrease in FEV(1) was suggested for female workers. This was confirmed in a linear regression model adjusted...

  17. Relevancy of human exposure via house dust to the contaminants lead and asbestos

    NARCIS (Netherlands)

    Oomen AG; Lijzen JPA; SIR; LER

    2004-01-01

    The present report addresses the issues whether house dust is likely to contribute substantially to the exposure of humans, in particular for the contaminants lead and asbestos. House dust consists for 30-70% of soil material, indicating that contaminated soil can lead to contaminated house dust. It

  18. Mechanisms of particle-induced pulmonary inflammation in a mouse model: exposure to wood dust.

    Science.gov (United States)

    Määttä, Juha; Lehto, Maili; Leino, Marina; Tillander, Sari; Haapakoski, Rita; Majuri, Marja-Leena; Wolff, Henrik; Rautio, Sari; Welling, Irma; Husgafvel-Pursiainen, Kirsti; Savolainen, Kai; Alenius, Harri

    2006-09-01

    Repeated airway exposure to wood dust has long been known to cause adverse respiratory effects such as asthma and chronic bronchitis and impairment of lung function. However, the mechanisms underlying the inflammatory responses of the airways after wood dust exposure are poorly known. We used a mouse model to elucidate the mechanisms of particle-induced inflammatory responses to fine wood dust particles. BALB/c mice were exposed to intranasally administered fine (more than 99% of the particles had a particle size of dusts twice a week for 3 weeks. PBS, LPS, and titanium dioxide were used as controls. Intranasal instillation of birch or oak dusts elicited influx of inflammatory cells to the lungs in mice. Enhancement of lymphocytes and neutrophils was seen after oak dust exposure, whereas eosinophil infiltration was higher after birch dust exposure. Infiltration of inflammatory cells was associated with an increase in the mRNA levels of several cytokines, chemokines, and chemokine receptors in lung tissue. Oak dust appeared to be a more potent inducer of these inflammatory mediators than birch dust. The results from our in vivo mouse model show that repeated airway exposure to wood dust can elicit lung inflammation, which is accompanied by induction of several proinflammatory cytokines and chemokines. Oak and birch dusts exhibited quantitative and qualitative differences in the elicitation of pulmonary inflammation, suggesting that the inflammatory responses induced by the wood species may rise via different cellular mechanisms.

  19. Immunomodulatory effects of oak dust exposure in a murine model of allergic asthma.

    Science.gov (United States)

    Määttä, Juha; Haapakoski, Rita; Lehto, Maili; Leino, Marina; Tillander, Sari; Husgafvel-Pursiainen, Kirsti; Wolff, Henrik; Savolainen, Kai; Alenius, Harri

    2007-09-01

    Repeated airway exposure to wood dust has been reported to cause adverse respiratory effects such as asthma and chronic bronchitis. In our recent study, we found that exposure of mice to oak dust induced more vigorous lung inflammation compared to birch dust exposure. In the present study, we assessed the immunomodulatory effects of repeated intranasal exposure to oak dust both in nonallergic and in ovalbumin-sensitized, allergic mice. Allergen-induced influx of eosinophils and lymphocytes was seen in the lungs of allergic mice. Oak dust exposure elicited infiltration of neutrophils, lymphocytes, and macrophages in nonallergic mice. Interestingly, oak dust-induced lung neutrophilia as well as oak dust-induced production of the proinflammatory cytokine TNF-alpha and chemokine CCL3 were significantly suppressed in allergic mice. On the other hand, allergen-induced expression of IL-13 mRNA and protein was significantly reduced in oak dust-exposed allergic mice. Finally, allergen-induced airway hyperreactivity to inhaled metacholine was significantly suppressed in oak dust-exposed allergic mice. The present results suggest that repeated airway exposure to oak dust can regulate pulmonary inflammation and airway responses depending on the immunological status of the animal.

  20. Decreased osteoblasts and increased osteoclasts in rats after coal dust exposure

    Directory of Open Access Journals (Sweden)

    Izaak Zoelkarnain Akbar

    2016-02-01

    Full Text Available Bone remodeling is a physiological process of cortical and trabecular bone reconstruction, with initial bone resorption, by osteoclasts and concurrent bone formation by osteoblasts. Oxidative stress due to coal dust exposure is not only found in the lungs, but also in the circulation or systemically. The aim of this study was to determine the effect of oxidative stress from coal dust exposure on the number of osteoblasts and osteoclasts in rats. In this experimental study, four groups were evaluated: control; coal dust exposure at 6.25 mg/m3 for 28 days; coal dust exposure at 12.5 mg/m3 for 28 days; coal dust exposure at 25 mg/m3 for 28 days (all exposures were given daily for one hour. Circulatory oxidative stress was measured by malondialdehyde level. Osteoblast and osteoclast numbers were counted by light microscopic examination of distal femoral cross-sections stained with hematoxylin eosin. This study showed that malondialdehyde levels were significantly increased in coal dust exposure groups, in comparison with the control group (p0.05. Coal dust exposure increased malondialdehyde level and osteoclast numbers, and decreased osteoblast numbers, but no correlation was found between oxidative stress (caused by coal dust exposure and osteoblast and osteoclast numbers.

  1. Use of Factory-Waste Shingles and Cement Kiln Dust to Enhance the Performance of Soil Used in Road Works

    Directory of Open Access Journals (Sweden)

    Aly Ahmed

    2009-01-01

    Full Text Available An experimental work was conducted to study the use of factory-waste roof shingles to enhance the properties of fine-grained soil used in road works. Cement kiln dust (CKD, a cogenerated product of Portland cement manufacturing, was used as a stabilizing agent while the processed shingles were added to enhance the soil tensile strength. The effects of shingles on strength and stability were evaluated using the unconfined compressive strength, splitting tensile strength, and California Bearing Ratio (CBR tests. The results showed that the use of CKD alone resulted in a considerable increase in the unconfined compressive strength but had a small effect on the tensile strength. The addition of shingles substantially improved the tensile strength of the stabilized soil. A significant reduction in the capillary rise and a slight decrease in the permeability were obtained as a result of shingle addition. An optimal shingle content of 10% is recommended to stabilize the soil.

  2. Wood dust and formaldehyde exposures in the cabinet-making industry.

    Science.gov (United States)

    Sass-Kortsak, A M; Holness, D L; Pilger, C W; Nethercott, J R

    1986-12-01

    Time-weighted average (TWA) personal total and respirable dust exposures were determined gravimetrically for 48 subjects in 4 cabinet-making plants. TWA personal formaldehyde exposures also were obtained, with the use of 3M 3750 passive monitors. Selective area sampling for formaldehyde was undertaken using two methods. The results obtained with the passive monitors were compared to the standard chromotropic acid impinger method. Considerable variation was noted in the dust exposures. Cabinet-makers exposed to softwoods were found to have a mean exposure of approximately one half of the current applicable ACGIH TWA-TLV, while hard-wood exposure was twice the applicable TWA-TLV. The highest dust exposures were recorded for those workers sanding, the mean total dust being 2.91 mg/m3 (S.E. 0.70) and respirable dust 0.63 mg/m3 (S.E. 0.20). Sanding operations also were found to produce a higher proportion of respirable dust (22%) than other woodworking operations (6%-14%). Workers in assembly areas also were found to have higher dust exposures, likely reflecting the fact that conventional dust collection devices for stationary woodworking equipment are not appropriate for hand held tools and hand sanding. The importance of making respirable dust measurements is discussed. The poor correlation between paired total and respirable dust concentrations indicates that both measurements should be made. Some potential limitations to respirable wood dust sampling using 10 mm nylon cyclones are noted, however. Area dust concentrations were found to be significantly lower than personal exposures, emphasizing the importance of personal sampling data. Formaldehyde vapor exposures were very low, with a mean of 0.06 ppm (S.E. 0.01).

  3. Risk of Adverse Health and Performance Effects of Celestial Dust Exposure

    Science.gov (United States)

    Scully, Robert R.; Meyers, Valerie E.

    2015-01-01

    Crew members can be directly exposed to celestial dust in several ways. After crew members perform extravehicular activities (EVAs), they may introduce into the habitat dust that will have collected on spacesuits and boots. Cleaning of the suits between EVAs and changing of the Environmental Control Life Support System filters are other operations that could result in direct exposure to celestial dusts. In addition, if the spacesuits used in exploration missions abrade the skin, as current EVA suits have, then contact with these wounds would provide a source of exposure. Further, if celestial dusts gain access to a suit's interior, as was the case during the Apollo missions, the dust could serve as an additional source of abrasions or enhance suit-induced injuries. When a crew leaves the surface of a celestial body and returns to microgravity, the dust that is introduced into the return vehicle will "float," thus increasing the opportunity for ocular and respiratory injury. Because the features of the respirable fraction of lunar dusts indicate they could be toxic to humans, NASA conducted several studies utilizing lunar dust simulants and authentic lunar dust to determine the unique properties of lunar dust that affect physiology, assess the dermal and ocular irritancy of the dust, and establish a permissible exposure limit for episodic exposure to airborne lunar dust during missions that would involve no more than 6 months stay on the lunar surface. Studies, with authentic lunar soils from both highland (Apollo 16) and mare (Apollo17) regions demonstrated that the lunar soil is highly abrasive to a high fidelity model of human skin. Studies of lunar dust returned during the Apollo 14 mission from an area of the moon in which the soils were comprised of mineral constituents from both major geological regions (highlands and mares regions) demonstrated only minimal ocular irritancy, and pulmonary toxicity that was less than the highly toxic terrestrial crystalline

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

    Science.gov (United States)

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

    2004-01-01

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

  5. Respiratory function and exposure-effect relationships in wood dust-exposed and control workers.

    Science.gov (United States)

    Holness, D L; Sass-Kortsak, A M; Pilger, C W; Nethercott, J R

    1985-07-01

    The effect of wood dust exposure on 50 cabinet makers was examined. Woodworkers reported more nasal and eye symptoms and more cough, sputum and wheezing than did 49 control workers. More irritated cells were present in the woodworkers' nasal cytological smears. In contrast to the control workers, the woodworkers had a significant decline in lung function over the workshift. An inverse correlation between baseline lung function and an exposure index (mean area dust level multiplied by length of exposure) was demonstrated in the woodworkers. Greater dust exposure was not associated with larger falls in lung function over the work shift.

  6. Intranasal organic dust exposure-induced airway adaptation response marked by persistent lung inflammation and pathology in mice

    OpenAIRE

    Poole, Jill A.; Wyatt, Todd A; Oldenburg, Peter J.; Elliott, Margaret K.; West, William W.; Sisson, Joseph H.; Von Essen, Susanna G.; Romberger, Debra J.

    2009-01-01

    Organic dust exposure in agricultural environments results in an inflammatory response that attenuates over time, but repetitive exposures can result in chronic respiratory disease. Animal models to study these mechanisms are limited. This study investigated the effects of single vs. repetitive dust-induced airway inflammation in mice by intranasal exposure method. Mice were exposed to swine facility dust extract (DE) or saline once and once daily for 1 and 2 wk. Dust exposure resulted in inc...

  7. Comparative Benchmark Dose Modeling as a Tool to Make the First Estimate of Safe Human Exposure Levels to Lunar Dust

    Science.gov (United States)

    James, John T.; Lam, Chiu-wing; Scully, Robert R.

    2013-01-01

    Brief exposures of Apollo Astronauts to lunar dust occasionally elicited upper respiratory irritation; however, no limits were ever set for prolonged exposure ot lunar dust. Habitats for exploration, whether mobile of fixed must be designed to limit human exposure to lunar dust to safe levels. We have used a new technique we call Comparative Benchmark Dose Modeling to estimate safe exposure limits for lunar dust collected during the Apollo 14 mission.

  8. Non-malignant respiratory diseases and occupational exposure to wood dust. Part II. Dry wood industry.

    Science.gov (United States)

    Jacobsen, Gitte; Schaumburg, Inger; Sigsgaard, Torben; Schlunssen, Vivi

    2010-01-01

    This paper reviews the literature on associations between dry wood dust exposure and non-malignant respiratory diseases. Criteria for inclusion are epidemiological studies in English language journals with an internal or external control group describing relationships between dry wood dust exposure and respiratory diseases or symptoms. Papers took into consideration smoking and when dealing with lung function age. A total of 37 papers forms the basis of this review. The results support an association between dry wood dust exposure and asthma, asthma symptoms, coughing, bronchitis, and acute and chronic impairment of lung function. In addition, an association between wood dust exposure and rhino-conjunctivitis is seen across the studies. Apart from plicatic acid in western red cedar wood, no causal agent has consistently been disclosed. Type 1 allergy is not suspected to be a major cause of wood dust induced asthma.

  9. Human exposure to per- and polyfluoroalkyl substances (PFASs) via house dust in Korea: Implication to exposure pathway.

    Science.gov (United States)

    Tian, Zhexi; Kim, Seung-Kyu; Shoeib, Mahiba; Oh, Jeong-Eun; Park, Jong-Eun

    2016-05-15

    A wide range of per- and polyfluoroalkyl substances (PFASs), including fluorotelomer alcohols (FTOHs), perfluorooctane sulfonamidoethanols (FOSEs), perfluoroalkyl carboxylic acids (PFCAs), and perfluoroalkane sulfonic acids (PFSAs), were measured in fifteen house dust and two nonresidential indoor dust of Korea. Total concentrations of PFASs in house dust ranged from 29.9 to 97.6 ng g(-1), with a dominance of perfluorooctane sulfonic acid (PFOS), followed by 8:2 FTOH, N-Ethyl perfluorooctane sulfonamidoethanol (EtFOSE), perfluoroctanoic acid (PFOA). In a typical exposure scenario, the estimated daily intakes (EDIs) of total PFASs via house dust ingestion were 2.83 ng d(-1) for toddlers and 1.13 ng d(-1) for adults, which were within the range of the mean EDIs reported from several countries. For PFOA and PFOS exposure via house dust ingestion, indirect exposure (via precursors) was a minor contributor, accounting for 5% and 12%, respectively. An aggregated exposure (hereafter, overall-EDIs) of PFOA and PFOS occurring via all pathways, estimated using data compiled from the literature, were 53.6 and 14.8 ng d(-1) for toddlers, and 20.5 and 40.6 ng d(-1) for adults, respectively, in a typical scenario. These overall-EDIs corresponded to 82% (PFOA) and 92% (PFOS) of a pharmacokinetic model-based EDIs estimated from adults' serum data. Direct dietary exposure was a major contributor (>89% of overall-EDI) to PFOS in both toddlers and adults, and PFOA in toddlers. As for PFOA exposure of adults, however direct exposure via tap water drinking (37%) and indirect exposure via inhalation (22%) were as important as direct dietary exposure (41%). House dust-ingested exposure (direct+indirect) was responsible for 5% (PFOS in toddlers) and house-dust ingestion was a minor contributor in this study, but should not be ignored for toddlers' PFOS exposure due to its significance in the worst-case scenario.

  10. Western red cedar dust exposure and lung function: a dose-response relationship.

    Science.gov (United States)

    Noertjojo, H K; Dimich-Ward, H; Peelen, S; Dittrick, M; Kennedy, S M; Chan-Yeung, M

    1996-10-01

    The relationship between levels of cumulative red cedar dust exposure and decline in lung function was explored in an 11-yr follow-up study of 243 sawmill workers who participated in at least two occasions. We also studied 140 office workers in a similar manner as control subjects. Workers with asthma were excluded from the analysis. During the period of the study, 916 personal and 216 area samples of dust were collected from the sawmill. Cumulative wood dust exposure was calculated for each sawmill worker according to the duration and exposure in each job, based on the geometric mean of all dust measurements for that job. Average daily dust exposure was calculated by dividing the total cumulative exposure by the number of days of work. Workers were divided into low-, medium-, and high-exposure groups with mean daily level of exposure of 0.4 mg/m3, respectively. Sawmill workers had significantly greater declines in FEV1 and FVC compared with office workers adjusted for age, smoking, and initial lung function. A dose-response relationship was observed between the level of exposure and the annual decline in FVC. We conclude that exposure to Western red cedar dust is associated with a greater decline in lung function which may lead to development of chronic airflow limitation.

  11. Strength of Ternary Blended Cement Sandcrete Containing Afikpo Rice Husk Ash and Saw Dust Ash

    Directory of Open Access Journals (Sweden)

    L. O. Ettu

    2013-01-01

    Full Text Available This work investigated the compressive strength of ternary blended cement sandcrete containing Afikpo rice husk ash (RHA and sawdust ash (SDA. 105 sandcrete cubes of 150mm x 150mm x 150mm were produced with OPC-RHA binary blended cement, 105 with OPC-SDA binary blended cement, and 105 with OPC-RHA-SDA ternary blended cement, each at percentage OPC replacement with pozzolan of 5%, 10%, 15%, 20%, and 25%. Three cubes for each percentage replacement of OPC with pozzolan and the control were tested for saturated surface dry bulk density and crushed to obtain their compressive strengths at 3, 7, 14, 21, 28, 50, and 90 days of curing. The 90-day strengths obtained from ternary blending of OPC with equal proportions of RHA and SDA were 11.80N/mm2for 5% replacement, 11.20N/mm2for 10% replacement, 10.60N/mm2for 15% replacement, 10.00N/mm2for 20% replacement, and 9.10N/mm2for 25% replacement, while that of the control was 10.90N/mm2. This suggests that very high sandcrete strength values could be obtained with OPCRHA-SDA ternary blended cement with richer mixes, high quality control, and longer days of hydration. Thus, OPC-RHA-SDA ternary blended cement sandcrete could be used for various civil engineering and building works, especially where early strength is not a major requirement.

  12. Carpet-dust chemicals as measures of exposure: Implications of variability

    Directory of Open Access Journals (Sweden)

    Whitehead Todd P

    2012-03-01

    Full Text Available Abstract Background There is increasing interest in using chemicals measured in carpet dust as indicators of chemical exposures. However, investigators have rarely sampled dust repeatedly from the same households and therefore little is known about the variability of chemical levels that exist within and between households in dust samples. Results We analyzed 9 polycyclic aromatic hydrocarbons, 6 polychlorinated biphenyls, and nicotine in 68 carpet-dust samples from 21 households in agricultural communities of Fresno County, California collected from 2003-2005. Chemical concentrations (ng per g dust ranged from Conclusions Our findings suggest that attenuation bias should be relatively modest when using these semi-volatile carpet-dust chemicals as exposure surrogates in epidemiologic studies.

  13. Longitudinal lung function decline and wood dust exposure in the furniture industry.

    Science.gov (United States)

    Jacobsen, G; Schlünssen, V; Schaumburg, I; Taudorf, E; Sigsgaard, T

    2008-02-01

    The aim of the present study was to investigate the relationship between change in lung function and cumulative exposure to wood dust. In total, 1,112 woodworkers (927 males, 185 females) and 235 reference workers (104 males, 185 females) participated in a 6-yr longitudinal study. Forced expiratory volume in one second (FEV(1)), forced vital capacity (FVC), height and weight were measured, and questionnaire data on respiratory symptoms, wood dust exposure and smoking habits were collected. Cumulative inhalable wood dust exposure was assessed using a study-specific job exposure matrix and exposure time. The median (range) for cumulative wood dust exposure was 3.75 (0-7.55) mg x year x m(-3). A dose-response relationship between cumulative wood dust exposure and percent annual decrease in FEV(1) was suggested for female workers. This was confirmed in a linear regression model adjusted for confounders, including smoking, height and age. An additional difference of -14.50 mL x yr(-1) and -27.97 mL x yr(-1) was revealed for females exposed to 3.75-4.71 mg x yr x m(-3) or to >4.71 mg x yr x m(-3), respectively, compared with non-/low-exposed females. For females, a positive trend between wood dust exposure and the cumulative incidence proportion of FEV(1)/FVC lung function, which may be clinically relevant.

  14. Exposure to wood dust and endotoxin in small-scale wood industries in Tanzania.

    NARCIS (Netherlands)

    Rongo, L.M.B.; Msamanga, G.I.; Burstyn, I.; Barten, F.J.M.H.; Dolmans, W.M.V.; Heederik, D.

    2004-01-01

    Workers in small-scale wood industries (SSWI) have increased risks of developing asthma and other respiratory diseases. Wood dust and microbial agents have both been suggested to play a role, but few studies have measured endotoxin exposure in SSWI in Africa. We assessed inhalable dust levels in 281

  15. Trends in wood dust inhalation exposure in the UK, 1985-2005.

    NARCIS (Netherlands)

    Galea, K.S.; van Tongeren, M.; Sleeuwenhoek, A.J.; While, D.; Graham, M.; Bolton, A.; Kromhout, H.; Cherrie, J.W.

    2009-01-01

    OBJECTIVES: Wood dust data held in the Health and Safety Executive (HSE) National Exposure DataBase (NEDB) were reviewed to investigate the long-term changes in inhalation exposure from 1985 to 2005. In addition, follow-up sampling measurements were obtained from selected companies where exposure me

  16. Respiratory health effects and exposure to superabsorbent polymer and paper dust - an epidemiological study

    Directory of Open Access Journals (Sweden)

    Torén Kjell

    2011-07-01

    Full Text Available Abstract Background The primary aim of the present study was to investigate if exposure to dust from absorbent hygiene products containing superabsorbent polymer is related to symptoms from the airways and from the eyes. The secondary aim was to estimate the current exposure to superabsorbent polymer among production and maintenance workers in a plant producing hygiene products. Methods The cohort comprised 1043 workers of whom 689 were exposed to super absorbent polymer and 804 were exposed to paper dust (overlapping groups. There was 186 workers not exposed to either superabsorbent polymer or to paper dust They were investigated with a comprehensive questionnaire about exposure, asthma, rhinitis and symptoms from eyes and airways. The results were analyzed with logistic regression models adjusting for sex, age, atopy and smoking habits. An aerosol sampler equipped with a polytetrafluoroethylene filter with 1 μm pore size was used for personal samplings in order to measure inhalable dust and superabsorbent polymer. Results The prevalence of nasal crusts (OR 1.4, 95% CI 1.01-2.0 and nose-bleeding (OR 1.7, 95% CI 1.2-2.4 was increased among the paper dust exposed workers (adjusted for superabsorbent polymer exposure. There were no significant effects associated with exposure to superabsorbent polymer (adjusted for paper dust exposure. The average exposure to inhalable levels of total dust (paper dust varied between 0.40 and 1.37 mg/m3. For superabsorbent polymer dust the average exposure varied between 0.02 and 0.81 mg/m3. Conclusions In conclusion, our study shows that workers manufacturing diapers in the hygiene industry have an increased prevalence of symptoms from the nose, especially nose-bleeding. There was no relation between exposure to superabsorbent polymer and symptoms from eyes, nose or respiratory tract, but exposure to paper dust was associated with nose-bleeding and nasal crusts. This group of workers had also a considerable

  17. Association between Occupational Exposure to Wood Dust and Cancer: A Systematic Review and Meta-Analysis.

    Directory of Open Access Journals (Sweden)

    Montserrat Alonso-Sardón

    Full Text Available To perform a systematic review to analyze the association between occupational exposure to wood dust and cancer.A systematic literature search of entries made in the MEDLINE-PubMed database between 1957 and 2013 was conducted to identify studies that had assessed the relationship between occupational exposure to wood dust and different types of cancer. A meta-analysis of selected case-control and cohort studies was subsequently performed.A total of 114 studies were identified and 70 were selected for review. Of these, 42 studies focused on the relationship between wood dust and nasal cancer (n = 22, lung cancer (n = 11, and other types of cancer (n = 9. Low-to-moderate quality evidence that wood dust acts as a carcinogen was obtained, and a stronger association between wood dust and nasal adenocarcinoma was observed. A lesser association between wood dust exposure and lung cancer was also observed. Several studies suggested that there is a relationship between wood dust and the onset of other cancers, although there was no evidence to establish an association. A meta-analysis that included four case-controls studies showed that workers exposed to wood dust exhibited higher rates of nasal adenocarcinoma than other workers (odds ratio = 10.28; 95% confidence interval: 5.92 and 17.85; P<0,0001, although a large degree of heterogeneity was found.Low-to-moderate quality evidence supports a causal association between cancer and occupational exposure to wood dust, and this association was stronger for nasal adenocarcinoma than for lung cancer. There was no evidence of an association between wood dust exposure and the other cancers examined.

  18. Real-time measurement of dust in the workplace using video exposure monitoring: Farming to pharmaceuticals

    Science.gov (United States)

    Walsh, P. T.; Forth, A. R.; Clark, R. D. R.; Dowker, K. P.; Thorpe, A.

    2009-02-01

    Real-time, photometric, portable dust monitors have been employed for video exposure monitoring (VEM) to measure and highlight dust levels generated by work activities, illustrate dust control techniques, and demonstrate good practice. Two workplaces, presenting different challenges for measurement, were used to illustrate the capabilities of VEM: (a) poultry farming activities and (b) powder transfer operations in a pharmaceutical company. For the poultry farm work, the real-time monitors were calibrated with respect to the respirable and inhalable dust concentrations using cyclone and IOM reference samplers respectively. Different rankings of exposure for typical activities were found on the small farm studied here compared to previous exposure measurements at larger poultry farms: these were mainly attributed to the different scales of operation. Large variations in the ratios of respirable, inhalable and real-time monitor TWA concentrations of poultry farm dust for various activities were found. This has implications for the calibration of light-scattering dust monitors with respect to inhalable dust concentration. In the pharmaceutical application, the effectiveness of a curtain barrier for dust control when dispensing powder in a downflow booth was rapidly demonstrated.

  19. Inhalable dust and protein exposure in soybean processing plants.

    Science.gov (United States)

    Spies, Adri; Rees, David; Fourie, Anna M; Wilson, Kerry S; Harris-Roberts, Joanne; Robinson, Edward

    2008-01-01

    Little is known about inhalable dust concentrations in soybean processing plants in southern Africa. This project measured inhalable dust in soybean plants in the region and correlated dust measurements with total protein and soy trypsin inhibitor. Sixty-four personal inhalable dust measurements were taken in three processing plants. Levels of total protein and soy trypsin inhibitor were determined in only two of the three plants. Correlations between inhalable dust, total protein and trypsin inhibitor were determined for 44 of 64 samples. In plants' production areas, inhalable dust levels were 0.24-35.02 mg/m3 (median 2.58 mg/m3). Total protein and soy trypsin inhibitor levels were 29.41-448.82 microg/m3 (median 90.09 microg/m3) and 0.05-2.58 microg/m3 (median 0.07 microg/m3), respectively. No statistically significant correlations between presence of inhalable dust and soy trypsin inhibitor were found. Total protein and soy trypsin inhibitor were better correlated. This study indicates that total protein might be a good proxy for soybean specific protein concentrations in soybean processing plants.

  20. Organophosphorus flame retardants in house dust from the Philippines: occurrence and assessment of human exposure.

    Science.gov (United States)

    Kim, Joon-Woo; Isobe, Tomohiko; Sudaryanto, Agus; Malarvannan, Govindan; Chang, Kwang-Hyeon; Muto, Mamoru; Prudente, Maricar; Tanabe, Shinsuke

    2013-02-01

    The use of organophosphorus flame retardants (PFRs) as flame retardants and plasticizers has increased due to the ban on common polybrominated diphenyl ether mixtures. However, only limited information on PFR contamination is available so far from Southeast Asia. In the present study, residual levels of PFRs in house dust and exposure through dust ingestion were investigated in the Philippines. House dust samples (n = 37) were collected from Malate (residential area) and Payatas (municipal dumping area) in the Philippines and analyzed using ultra-high-performance liquid chromatography coupled with tandem mass spectrometry. Among the targeted seven PFRs, triphenyl phosphate (TPP) was the predominant compound. Median levels of ΣPFRs in Malate (530 ng/g) were two times higher (p < 0.05) than in Payatas (240 ng/g). The estimated daily intake of PFRs in the Philippines (of areas studied) via house dust ingestion was below the guideline values. House dust may be an important contributor in the overall exposure of humans to TPP even when considering dietary sources. To our knowledge, this is a first report on PFR contamination in house dust from developing country. PFRs were ubiquitously detected in the home environments in the Philippines. Although estimated exposure levels through dust ingestion were below the guideline, it was suggested that toddlers are at higher risk. Therefore, further investigations to understand the behavior of PFRs in house and other microenvironments and overall exposure pathways for the country's populace to PFRs are necessary.

  1. Prevalence and Determinants of Mucous Membrane Irritations in a Community Near a Cement Factory in Zambia: A Cross Sectional Study

    OpenAIRE

    2015-01-01

    Exposure to cement dust has been associated with deleterious health effects in humans. This study investigated whether residing near a cement factory increases the risk of irritations to the mucous membranes of the eyes and respiratory system. A cross sectional study was conducted in Freedom Compound, a community bordering a cement factory in Chilanga, Zambia and a control community, Bauleni, located 18 km from the cement plant. A modified American Thoracic Society questionnaire was administe...

  2. Occupational dust exposure and chronic obstructive pulmonary disease. A systematic overview of the evidence.

    Science.gov (United States)

    Oxman, A D; Muir, D C; Shannon, H S; Stock, S R; Hnizdo, E; Lange, H J

    1993-07-01

    The object of this study was to assess the relationship between occupational dust exposure and chronic obstructive pulmonary disease (COPD). Studies were identified using MEDLINE (January 1966 to July 1991), SCISEARCH, manual review of reference lists, and personal contact with more than 30 international experts. Studies of COPD, lung function, emphysema, chronic bronchitis, or mortality in workers exposed to nonorganic dust were retrieved. Studies were included if dust exposure was measured quantitatively, and a quantitative relationship between dust exposure and one of the outcomes of interest was calculated while controlling at least for smoking and age. Methodological rigor was assessed, and data regarding the study populations, prognostic factors, and outcomes were extracted independently by two reviewers. Thirteen reports derived from four cohorts of workers met our inclusion criteria. Three of the cohorts were of coal miners and one was of gold miners. All of the studies found a statistically significant association between loss of lung function and cumulative respirable dust exposure. It was estimated that 80 (95% CI, 34 to 137) of 1,000 nonsmoking coal miners with a cumulative respirable dust exposure of 122.5 gh/m3 (considered equivalent to 35 years of work with a mean respirable dust level of 2 mg/m3) could be expected to develop a clinically important (> 20%) loss of FEV1 attributable to dust. Among 1,000 smoking miners the comparable estimate was 66 (95% CI, 49 to 84). The risk of a clinically important loss of lung function attributable to dust among nonsmoking gold miners was estimated to be three times as large as for coal miners at less than one fifth of the cumulative respirable dust exposure (21.3 gh/m3), the maximal exposure observed among the cohort of gold miners. We conclude that occupational dust is an important cause of COPD, and the risk appears to be greater for gold miners than for coal miners. One possible explanation of the greater

  3. The University of Michigan Dioxin Exposure Study: estimating residential soil and house dust exposures to young children.

    Science.gov (United States)

    Paustenbach, Dennis J; Kerger, Brent D

    2013-04-01

    The University of Michigan Dioxin Exposure Study provides extensive data on elevated residential soil and house dust concentrations of polychlorinated dioxins and dibenzofurans (PCDD/Fs) and adult body burdens among residents near a chemical manufacturing plant in Midland, Michigan. Recent reports found no significant contribution of residential soil/dust concentrations to serum lipid PCDD/Fs in adults. Although child body burdens were not studied by the University of Michigan, internal dose modeling that incorporates recent findings on demonstrated shorter elimination half life of PCDD/Fs in children (1-2 year half life in children vs. ~7 years in older adults) can be applied to assess this important issue. The model examines children (ages 0-7 years) with background dietary intake and exposure to residential soils at selected concentrations (10, 100 and 1000 pg/g 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalents, TEQ) using the congener patterns observed in Midland. Model predictions assuming 50th percentile TEQ uptake from soil/dust-related dermal and ingestion exposures indicate no measurable changes in serum lipid TEQ concentrations up to 1000 pg/g in soil/dust. Assuming 95th percentile uptake, the model shows no measurable serum lipid TEQ change up to 100 pg/g in soil/dust, but serum lipid TEQ levels rose ~2 pg/g at 1000 pg/g in soil/dust. Since the vast majority of soil/dust data were below 100 pg/g, Michigan children exposed to such soil/dust TEQ concentrations are not reasonably expected to exhibit measurable changes in serum lipid TEQ concentrations when compared to typical background dietary exposures. With adequate data, this approach can be applied to evaluate child dose and risk for other persistent chemicals.

  4. Phthalates, non-phthalate plasticizers and bisphenols in Swedish preschool dust in relation to children's exposure.

    Science.gov (United States)

    Larsson, Kristin; Lindh, Christian H; Jönsson, Bo Ag; Giovanoulis, Georgios; Bibi, Momina; Bottai, Matteo; Bergström, Anna; Berglund, Marika

    2017-03-05

    Children are exposed to a wide range of chemicals in their everyday environments, including the preschool. In this study, we evaluated the levels of phthalates, non-phthalate plasticizers and bisphenols in dust from 100 Swedish preschools and identified important exposure factors in the indoor environment. In addition, children's total exposure to these chemicals was determined by urine analysis to investigate their relation with dust exposure, and to explore the time trends by comparing with children who provided urine fifteen years earlier. The most abundant plasticizers in preschool dust were the phthalates di-isononyl phthalate (DiNP) and di-(2-ethylhexyl) phthalate (DEHP) with geometric mean levels of 450 and 266μg/g dust, respectively, and the non-phthalate plasticizers bis(2-ethylhexyl) terephthalate (DEHT) and diisononylcyclohexane-1,2-dicarboxylate (DiNCH) found at 105 and 73μg/g dust, respectively. The levels of several substitute plasticizers were higher in newer preschools, whereas the levels of the strictly regulated phthalate di-n-butyl phthalate (DnBP) were higher in older preschools. The presence of foam mattresses and PVC flooring in the sampling room were associated with higher levels of DiNP in dust. Children's exposure from preschool dust ingestion was below established health based reference values and the estimated exposure to different phthalates and BPA via preschool dust ingestion accounted for 2-27% of the total exposure. We found significantly lower urinary levels of BPA and metabolites of strictly regulated phthalates, but higher levels of DiNP metabolites, in urine from the children in this study compared to the children who provided urine samples fifteen years earlier.

  5. French children's exposure to metals via ingestion of indoor dust, outdoor playground dust and soil: contamination data.

    Science.gov (United States)

    Glorennec, Philippe; Lucas, Jean-Paul; Mandin, Corinne; Le Bot, Barbara

    2012-09-15

    In addition to dietary exposure, children are exposed to metals via ingestion of soils and indoor dust, contaminated by natural or anthropogenic outdoor and indoor sources. The objective of this nationwide study was to assess metal contamination of soils and dust which young French children are exposed to. A sample of 484 children (6 months to 6 years) was constituted in order to obtain representative results for young French children. In each home indoor settled dust was sampled by a wipe in up to five rooms. Outdoor playgrounds were sampled with a soil sample ring (n=315) or with a wipe in case of hard surfaces (n=53). As, Cd, Cr, Cu, Mn, Pb, Sb, Sr, and V were measured because of their potential health concern due to soil and dust ingestion. The samples were digested with hydrochloric acid, and afterwards aqua regia in order to determine both leachable and total metal concentrations and loadings by mass spectrometry with a quadrupole ICP-MS. In indoor settled dust most (total) loadings were below the Limit of Quantification (LOQ), except for Pb and Sr, whose median loadings were respectively 9 and 10 μg/m². The 95th percentile of loadings were 2 μg/m² for As, playgrounds were 2/16, playground soil median/95th percentile of concentrations (μg/g) were 8/26, soil and dust and the associated risks in urban and rural environments. Ratios of leachable/total concentrations and loadings, calculated on >LOQ measurements, differed among metals. To a lesser extent, they were also affected by type of matrix, with (except for Cd) a greater leachability of dust (especially indoor) compared to soils.

  6. Occupational exposure to poultry dust and effects on the respiratory system in workers.

    Science.gov (United States)

    Viegas, S; Faísca, V M; Dias, H; Clérigo, A; Carolino, E; Viegas, C

    2013-01-01

    Farmers are occupationally exposed to many respiratory hazards at work and display higher rates of asthma and respiratory symptoms than other workers. Dust is one of the components present in poultry production that increases risk of adverse respiratory disease occurrence. Dust originates from poultry residues, molds, and feathers and is biologically active as it contains microorganisms. Exposure to dust is known to produce a variety of clinical responses, including asthma, chronic bronchitis, chronic airways obstructive disease (COPD), allergic alveolitis, and organic dust toxic syndrome (ODTS). A study was developed to determine particle contamination in seven poultry farms and correlate this with prevalence rate of respiratory defects and record by means of a questionnaire the presence of clinical symptoms associated with asthma and other allergy diseases by European Community Respiratory Health Survey. Poultry farm dust contamination was found to contain higher concentrations of particulate matter (PM) PM5 and PM10. Prevalence rate of obstructive pulmonary disorders was higher in individuals with longer exposure regardless of smoking status. In addition, a high prevalence for asthmatic (42.5%) and nasal (51.1%) symptoms was noted in poultry workers. Data thus show that poultry farm workers are more prone to suffer from respiratory ailments and this may be attributed to higher concentrations of PM found in the dust. Intervention programs aimed at reducing exposure to dust will ameliorate occupational working conditions and enhance the health of workers.

  7. Wood dust exposure and lung cancer risk: a meta-analysis.

    Science.gov (United States)

    Hancock, David G; Langley, Mary E; Chia, Kwan Leung; Woodman, Richard J; Shanahan, E Michael

    2015-12-01

    Occupational lung cancers represent a major health burden due to their increasing prevalence and poor long-term outcomes. While wood dust is a confirmed human carcinogen, its association with lung cancer remains unclear due to inconsistent findings in the literature. We aimed to clarify this association using meta-analysis. We performed a search of 10 databases to identify studies published until June 2014. We assessed the lung cancer risk associated with wood dust exposure as the primary outcome and with wood dust-related occupations as a secondary outcome. Random-effects models were used to pool summary risk estimates. 85 publications were included in the meta-analysis. A significantly increased risk for developing lung cancer was observed among studies that directly assessed wood dust exposure (RR 1.21, 95% CI 1.05 to 1.39, n=33) and that assessed wood dust-related occupations (RR 1.15, 95% CI 1.07 to 1.23, n=59). In contrast, a reduced risk for lung cancer was observed among wood dust (RR 0.63, 95% CI 0.39 to 0.99, n=5) and occupation (RR 0.96, 95% CI 0.95 to 0.98, n=1) studies originating in Nordic countries, where softwood dust is the primary exposure. These results were independent of the presence of adjustment for smoking and exposure classification methods. Only minor differences in risk between the histological subtypes were identified. This meta-analysis provides strong evidence for an association between wood dust and lung cancer, which is critically influenced by the geographic region of the study. The reasons for this region-specific effect estimates remain to be clarified, but may suggest a differential effect for hardwood and softwood dusts.

  8. Occupational exposure to organic dust increases lung cancer risk in the general population

    NARCIS (Netherlands)

    Peters, Susan; Kromhout, Hans; Olsson, Ann C.; Wichmann, Heinz-Erich; Brueske, Irene; Consonni, Dario; Landi, Maria Teresa; Caporaso, Neil; Siemiatycki, Jack; Richiardi, Lorenzo; Mirabelli, Dario; Simonato, Lorenzo; Gustavsson, Per; Plato, Nils; Joeckel, Karl-Heinz; Ahrens, Wolfgang; Pohlabeln, Hermann; Boffetta, Paolo; Brennan, Paul; Zaridze, David; Cassidy, Adrian; Lissowska, Jolanta; Szeszenia-Dabrowska, Neonila; Rudnai, Peter; Fabianova, Eleonora; Forastiere, Francesco; Bencko, Vladimir; Foretova, Lenka; Janout, Vladimir; Stuecker, Isabelle; Dumitru, Rodica Stanescu; Benhamou, Simone; Bueno-de-Mesquita, Bas; Kendzia, Benjamin; Pesch, Beate; Straif, Kurt; Bruening, Thomas; Vermeulen, Roel

    2012-01-01

    Background Organic dust is a complex mixture of particulate matter from microbial, plant or animal origin. Occupations with exposure to animal products have been associated with an increased lung cancer risk, while exposure to microbial components (eg, endotoxin) has been associated with a decreased

  9. Evaluation of coral pathogen growth rates after exposure to atmospheric African dust samples

    Science.gov (United States)

    Lisle, John T.; Garrison, Virginia H.; Gray, Michael A.

    2014-01-01

    Laboratory experiments were conducted to assess if exposure to atmospheric African dust stimulates or inhibits the growth of four putative bacterial coral pathogens. Atmospheric dust was collected from a dust-source region (Mali, West Africa) and from Saharan Air Layer masses over downwind sites in the Caribbean [Trinidad and Tobago and St. Croix, U.S. Virgin Islands (USVI)]. Extracts of dust samples were used to dose laboratory-grown cultures of four putative coral pathogens: Aurantimonas coralicida (white plague type II), Serratia marcescens (white pox), Vibrio coralliilyticus, and V. shiloi (bacteria-induced bleaching). Growth of A. coralicida and V. shiloi was slightly stimulated by dust extracts from Mali and USVI, respectively, but unaffected by extracts from the other dust sources. Lag time to the start of log-growth phase was significantly shortened for A. coralicida when dosed with dust extracts from Mali and USVI. Growth of S. marcescens and V. coralliilyticus was neither stimulated nor inhibited by any of the dust extracts. This study demonstrates that constituents from atmospheric dust can alter growth of recognized coral disease pathogens under laboratory conditions.

  10. Metal Dust Exposure and Respiratory Health of Male Steel Work¬ers in Terengganu, Malaysia

    Directory of Open Access Journals (Sweden)

    Nurul Ainun HAMZAH

    2015-10-01

    Full Text Available Background: This cross sectional study was carried out to determine the relationship between metal dust exposure and respiratory health in male steel workers in Terengganu, Malaysia.Methods: Subjects were interviewed using a structured questionnaire from British Medical Research Council (BMRC Questionnaire regarding respiratory symptoms and were examined their lung function using spirometer.Results: The mean trace metal dusts concentration TWA8 for cobalt and chromium in most of work unit exceeded occupational exposure prescribed values. Prevalence of chest tightness, chronic phlegm, and shortness of breath was 28.0%, 26.8%, 24.1%, and 20.2% respectively. Age and smoking were among the factors associated with respiratory symptoms (OR: 0.92 – 1.78. Smoking and cumulative respirable metal dust were negatively associated with FEV1.Conclusion: The mean metal dust for cobalt and chromium were 1 to 2 times higher than permissible exposure limit (PEL. This study found that respirable cumulative metal dust exposure is one of the contributing factors to lung function values among steel workers. Keywords: Respiratory symptoms, Lung function, Metal dust, Questionnaire

  11. [Dust exposure in a pottery plant assessed by using GRIMM dust monitor].

    Science.gov (United States)

    Woźniak, Helena; Stroszejn-Mrowca, Grazyna; Kita, Natalia

    2002-01-01

    In one of the pottery plants in which pneumoconiosis was the only certified occupational disease (16 cases during the years 1984-1997), the concentrations of dust in inhalable, thoracic and respirable fractions were measured at most characteristic workplaces. The highest concentrations in all the three fractions was found in the slip house; the mean concentrations were as follows: inhalable dust-7231.8 mg/m3; thoracic fraction--4834.9 mg/m3; and respirable fraction 1402.2 mg/m3. High concentrations of all the dust fractions were also observed at the workplace of the intershop transport worker who removed the waste body from cast and throw shops. The largest number of pneumoconiosis (7) cases was found among the workers of the slip house (20 persons employed); this was followed by the intershop transport workers-4 cases (4 persons employed). At the other workplaces (cast shop, throw shop and firing), concentrations of inhalable dust ranged from 1175 to 3232 mg/m3; thoracic from 726 to 2001 mg/m3; and respirable from 146 to 549 mg/m3. The contents of free crystalline silica (SiO2) in the air dust ranged from 3% in firing to 50% in slip house, in the latter mostly in the form of quartz or cristobalite. The main fraction of inhalable dust was the tracheobronchial fraction, ranging from 43.1 to 48.2%, the extrathoracic fraction ranged from 32.8 to 42.3% and respirable fraction from 11.8 to 21.6%. On the basis of the graphic record, such activities as pouring of raw materials into grinding mill and reloading of the waste body were identified at the workplaces of slip making and internship transport as those associated with the highest dust emission.

  12. Occupational exposure to Polycyclic Aromatic Hydrocarbons in wood dust

    Energy Technology Data Exchange (ETDEWEB)

    Huynh, C K; Schuepfer, P; Boiteux, P, E-mail: chuynh@hospvd.c [Institute for Work and Health, rue du Bugnon 21, CH-1005 Lausanne (Switzerland)

    2009-02-01

    Sino-nasal cancer (SNC) represents approximately 3% of Oto-Rhino-Laryngology (ORL) cancers. Adenocarcinoma SNC is an acknowledged occupational disease affecting certain specialized workers such as joiners and cabinetmakers. The high proportion of woodworkers contracting a SNC, subjected to an estimated risk 50 to 100 times higher than that affecting the general population, has suggested various study paths to possible causes such as tannin in hardwood, formaldehyde in plywood and benzo(a)pyrene produced by wood when overheated by cutting tools. It is acknowledged that tannin does not cause cancer to workers exposed to tea dust. Apart from being an irritant, formaldehyde is also classified as carcinogenic. The path involving carcinogenic Polycyclic Aromatic Hydrocarbons (PAHs) emitted by overheated wood is attractive. In this study, we measured the particle size and PAHs content in dust emitted by the processing of wood in an experimental chamber, and in field situation. Quantification of 16 PAHs is carried out by capillary GC-ion trap Mass Spectrometric analysis (GC-MS). The materials tested are rough fir tree, oak, impregnated polyurethane (PU) oak. The wood dust contains carcinogenic PAHs at the level of mug.g{sup -1} or ppm. During sanding operations, the PU varnish-impregnated wood produces 100 times more PAHs in dust than the unfinished wood.

  13. Quantitative Risk Assessment for Lung Cancer from Exposure to Metal Ore Dust

    Institute of Scientific and Technical Information of China (English)

    FUHUA; JINGXIPENG; 等

    1992-01-01

    To quantitatively assess risk for lung cancer of metal miners,a historical cohort study was conducted.The cohort consisted of 1113 miners who were employed to underground work for at least 12 months between January 1,1960and December,12,1974,According to the records or dust concentration,a cumulative dust dose of each miner in the cohort was estimated.There wer 162 deaths in total and 45 deaths from lung cancer with a SMR of 2184,The SMR for lung cancer increased from 1019 for those with cumulative dust of less than 500mg-year to 2469 for those with the dose of greater than 4500mg-year.Furthermore,the risk in the highest category of combined cumulative dust dose and cigarette smoking was 46-fold greater than the lowest category of dust dose and smoking.This study showed that there was an exposure-response relationship between metal ore dust and lung cancer,and an interaction of lung cancer between smoking and metal ore dust exposure.

  14. Evaluating portland cement concrete degradation by sulphate exposure through artificial neural networks modeling

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, Douglas Nunes de; Bourguignon, Lucas Gabriel Garcia; Tolentino, Evandro, E-mail: tolentino@timoteo.cefetmg.br [Centro Federal de Educacao Tecnologica de Minas Gerais (CEFET-MG), Timoteo, MG (Brazil); Costa, Rodrigo Moyses, E-mail: rodrigo@moyses.com.br [Universidade de Itauna, Itauna, MG (Brazil); Tello, Cledola Cassia Oliveira de, E-mail: tellocc@cdtn.br [Centro de Desenvolvimento da Tecnologia Nucelar (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2015-07-01

    A concrete is durable if it has accomplished the desired service life in the environment in which it is exposed. The durability of concrete materials can be limited as a result of adverse performance of its cement-paste matrix or aggregate constituents under either chemical or physical attack. Among other aggressive chemical exposures, the sulphate attack is an important concern. Water, soils and gases, which contain sulphate, represent a potential threat to the durability of concrete structures. Sulphate attack in concrete leads to the conversion of the hydration products of cement to ettringite, gypsum, and other phases, and also it leads to the destabilization of the primary strength generating calcium silicate hydrate (C-S-H) gel. The formation of ettringite and gypsum is common in cementitious systems exposed to most types of sulphate solutions. The present work presents the application of the neural networks for estimating deterioration of various concrete mixtures due to exposure to sulphate solutions. A neural networks model was constructed, trained and tested using the available database. In general, artificial neural networks could be successfully used in function approximation problems in order to approach the data generation function. Once data generation function is known, artificial neural network structure is tested using data not presented to the network during training. This paper is intent to provide the technical requirements related to the production of a durable concrete to be used in the structures of the Brazilian near-surface repository of radioactive wastes. (author)

  15. Pulmonary Inflammatory Responses To Acute Meteorite Dust Exposures - Implications For Human Space Exploration

    Science.gov (United States)

    Harrington, A. D.; McCubbin, F. M.; Kaur, J.; Smirnov, A.; Galdanes, K.; Schoonen, M. A. A.; Chen, L. C.; Tsirka, S. E.; Gordon, T.

    2017-01-01

    The previous manned missions to the Moon represent milestones of human ingenuity, perseverance, and intellectual curiosity. However, one of the major ongoing concerns is the array of hazards associated with lunar surface dust. Not only did the dust cause mechanical and structural integrity issues with the suits, the dust 'storm' generated upon reentrance into the crew cabin caused "lunar hay fever" and "almost blindness" (Figure 1). It was further reported that the allergic response to the dust worsened with each exposure. The lack of gravity exacerbated the exposure, requiring the astronauts to wear their helmet within the module in order to avoid breathing the irritating particles. Due to the prevalence of these high exposures, the Human Research Roadmap developed by NASA identifies the Risk of Adverse Health and Performance Effects of Celestial Dust Exposure as an area of concern. Extended human exploration will further increase the probability of inadvertent and repeated exposures to celestial dusts. Going forward, hazard assessments of celestial dusts will be determined through sample return efforts prior to astronaut deployment. Studies on the lunar highland regolith indicate that the dust is not only respirable but also reactive, and previous studies concluded that it is moderately toxic; generating a greater response than titanium oxide but a lower response than quartz. The presence of reactive oxygen species (ROS) on the surface of the dust has been implicated. However, there is actually little data related to physicochemical characteristics of particulates and pulmonary toxicity, especially as it relates to celestial dust exposure. As a direct response to this deficit, the present study evaluates the role of a particulate's innate geochemical features (e.g., bulk chemistry, internal composition, morphology, size, and reactivity) in generating adverse toxicological responses in vitro and in vivo. This highly interdisciplinary study evaluates the relative

  16. 76 FR 12648 - Lowering Miners' Exposure to Respirable Coal Mine Dust, Including Continuous Personal Dust Monitors

    Science.gov (United States)

    2011-03-08

    .... (2) Electronic mail: zzMSHA-comments@dol.gov . Include ``RIN 1219- AB64'' in the subject line of the message. (3) Facsimile: 202-693-9441. Include ``RIN 1219-AB64'' in the subject line of the message. (4... on appropriate timeframes to switch out sampling devices, Coal Mine Dust Personal Sampler...

  17. Accumulation of eosinophils and T-lymphocytes in the lungs after exposure to pinewood dust.

    Science.gov (United States)

    Gripenbäck, S; Lundgren, L; Eklund, A; Lidén, C; Skare, L; Tornling, G; Grunewald, J

    2005-01-01

    Exposure to wood dust within the woodworking industry has been shown to cause a variety of respiratory disorders. The aim of this study was to investigate the cellular effects in bronchoalveolar lavage (BAL) fluid and peripheral blood from healthy individuals exposed to pinewood dust. Eleven healthy volunteers were exposed to pinewood dust for 1 h in a whole-body exposure chamber. BAL fluid and blood cells were differentially counted and the expression of activation, adhesion and subset markers on alveolar macrophages and T-lymphocytes was determined 2-6 weeks before and 20 h after the exposure. Following pinewood dust exposure, the total BAL fluid cell concentration increased from 81.4 (64.1-97.5) x 10(6) cells x L(-1) (median (interquartile range)) to 195.3 (154.6-341.2) x 10(6) cells x L(-1). The BAL fluid T-lymphocyte concentration increased from 3.8% (3.5-6.5%) to 7.6% (4.9-11.2%), and BAL fluid eosinophil concentration from 0.0% (0.0-0.2%) to 1.8% (0.6-3.5%). Inhalation of pinewood dust leads to the recruitment of inflammatory cells to the airways of healthy individuals. The increase in numbers of eosinophils, T-lymphocytes and mast cells, i.e. cells of crucial importance to airway inflammation, in the lungs may be related to the increased risk of developing respiratory disorders among woodworkers.

  18. Respirable quartz dust exposure and airway obstruction: a systematic review and meta-analysis.

    Science.gov (United States)

    Brüske, Irene; Thiering, Elisabeth; Heinrich, Joachim; Huster, Katharina M; Nowak, Dennis

    2014-08-01

    Studies on exposure to respirable quartz dust at the workplace and the development of chronic obstructive pulmonary disease (COPD) were selected into a systematic review and meta-analysed to obtain an overall estimate of forced expiratory volume in 1 s (FEV1) and FEV1/forced vital capacity (FVC) reduction. PubMed and Embase were searched from 1970 to 2010. In total, 257 cross-sectional and longitudinal studies were identified that reported on inorganic dust exposure and had available lung function data. Of the 55 publications which met our inclusion criteria, 11 reported on associations with occupational exposure to respirable quartz dust. The combined average effect estimate of respirable quartz dust on spirometric parameters was obtained using a random effects model meta-analysis. Between-study heterogeneity was assessed via the I(2) statistic. Most studies found a significant negative association of FEV1 and FEV1/FVC related to increasing exposure to crystalline quartz at the workplace. One study found an effect only for smokers, and one did not observe such an effect at all. The meta-analysis of cross-sectional studies showed that the mean ratio FEV1 to FVC was reduced and FEV1 of workers exposed to respirable quartz dust was 4.6% less than predicted compared with workers with no/low exposure. Both results showed a statistically significant difference. Occupational exposure to respirable quartz dust was associated with a statistically significant decrease in FEV1 and FEV1/FVC, revealing airway obstruction consistent with COPD.

  19. Characterization of exposures among cemented tungsten carbide workers. Part I: Size-fractionated exposures to airborne cobalt and tungsten particles.

    Science.gov (United States)

    Stefaniak, Aleksandr B; Virji, M Abbas; Day, Gregory A

    2009-07-01

    As many as 30,000 workers in the United States of America are exposed to cemented tungsten carbides (CTC), alloys composed primarily of tungsten carbide and cobalt, which are used in cutting tools. Inhalation of cobalt-containing particles may be sufficient for the development of occupational asthma, whereas tungsten carbide particles in association with cobalt particles are associated with the development of hard metal disease (HMD) and lung cancer. Historical epidemiology and exposure studies of CTC workers often rely only on measures of total airborne cobalt mass concentration. In this study, we characterized cobalt- and tungsten-containing aerosols generated during the production of CTC with emphasis on (1) aerosol "total" mass (n=252 closed-face 37 mm cassette samples) and particle size-selective mass concentrations (n=108 eight-stage cascade impactor samples); (2) particle size distributions; and (3) comparison of exposures obtained using personal cassette and impactor samplers. Total cobalt and tungsten exposures were highest in work areas that handled powders (e.g., powder mixing) and lowest in areas that handled finished product (e.g., grinding). Inhalable, thoracic, and respirable cobalt and tungsten exposures were observed in all work areas, indicating potential for co-exposures to particles capable of getting deposited in the upper airways and alveolar region of the lung. Understanding the risk of CTC-induced adverse health effects may require two exposure regimes: one for asthma and the other for HMD and lung cancer. All sizes of cobalt-containing particles that deposit in the lung and airways have potential to cause asthma, thus a thoracic exposure metric is likely biologically appropriate. Cobalt-tungsten mixtures that deposit in the alveolar region of the lung may potentially cause HMD and lung cancer, thus a respirable exposure metric for both metals is likely biologically appropriate. By characterizing size-selective and co-exposures as well as

  20. Engineering controls for selected silica and dust exposures in the construction industry--a review.

    Science.gov (United States)

    Flynn, Michael R; Susi, Pam

    2003-04-01

    This literature review summarizes engineering control technology research for dust and silica exposures associated with selected tasks in the construction industry. Exposure to crystalline silica can cause silicosis and lung fibrosis, and evidence now links it with lung cancer. Of over 30 references identified and reviewed, 16 were particularly significant in providing data and analyses capable of documenting the efficacy of various engineering controls. These reports include information on generation rates and worker exposures to silica and dust during four different tasks: cutting brick and concrete block, grinding mortar from between bricks, drilling, and grinding concrete surfaces. The major controls are wet methods and local exhaust ventilation. The studies suggest that while the methods provide substantial exposure reductions, they may not reduce levels below the current ACGIH threshold limit value (TLV) of 0.05 mg/m(3) for respirable quartz. Although further research on controls for these operations is indicated, it is clear that effective methods exist for significant exposure reduction.

  1. Assessment of Occupational Exposure to Dust and Crystalline Silica in Foundries

    OpenAIRE

    Ali OMIDIANIDOST; Mehdi GHASEMKHANI; Azari, Mansour R.; Golbabaei,Farideh

    2015-01-01

    Background: The term “crystalline silica” refers to crystallized form of SiO2 and quartz, as the most abundant compound on the earth’s crust; it is capable of causing silicosis and lung cancer upon inhaling large doses in the course of occupational exposure. The aim of this study was to assess occupational exposure to dust and crystalline silica in foundries in Pakdasht, Iran. Materials and Methods: In this study, airborne dust samples were collected on PVC filters (37 mm diameter, 0.8 mm por...

  2. The Effects of Exposure Time on the Surface Microhardness of Three Dual-Cured Dental Resin Cements

    Directory of Open Access Journals (Sweden)

    Matheus C. Bandéca

    2011-06-01

    Full Text Available This study evaluated the exposure time of light-curing of the polymers used for cementation on microhardness test in different storage times. The polymers (specifically called resin cements were RelyX ARC, RelyX U100, and SET. Five specimens of each group were prepared and photo-polymerized with exposure times of 20 s and 180 s, using a LED polymerization unit with wavelength of 440 ~ 480 nm and light output was consistently 1,500 mW/cm2. The Vickers hardness test was performed in a MMT-3 Microhardness Tester. Data were submitted to ANOVA and Tukey's test (α = 0.05. The values of RelyX ARC showed statistically significant difference to groups with light exposure when considering only chemical cure (p < 0.05. The groups with light exposure (20 s and 180 s showed no significant difference between them (p > 0.05. The RelyX U100 cured only chemically showed statistically significant difference between 48 h and 7 days (p < 0.05. The SET resin cement showed no significant difference to groups without light exposure for all storage times (p > 0.05. The values of hardening of the dual-cured resin cements improved after setting by light and chemical activation demonstrating the importance of light curing.

  3. Biomonitoring Study of Heavy Metals in Blood from a Cement Factory Based Community

    OpenAIRE

    Bank M.S.; Spengler J.D.

    2014-01-01

    Little is known about the effects of cement factory pollution, emissions, and kiln dust on contaminant exposure in human populations, including school environments, in close proximity to these point sources. In Ravena, New York, USA and vicinity, environmental pollution from a local cement plant is considered significant and substantial according to the United States Environmental Protection Agency’s Toxic Release Inventory, published in 2006, 2007, and 2010. We hypothesized that cement facto...

  4. A study on respiratory problems and pulmonary function indexes among cement industry workers in Mashhad, Iran

    OpenAIRE

    Ehsan Rafeemanesh; Ashkan Alizadeh; Lahya Afshari Saleh; Hosein Zakeri

    2015-01-01

    Background: The respiratory system is the most vulnerable system in the cement industry. This study was conducted to determine the effects of occupational exposure to cement dust on the respiratory system more thoroughly. Material and Methods: In this cross sectional study an interviewer-administered questionnaire on socio-demographic characteristics and respiratory symptoms was completed and pulmonary function tests were carried out on 100 exposed and 120 non-exposed workers at the cement fa...

  5. [Lung tissue in intratracheal exposure to mine dust].

    Science.gov (United States)

    Mikhaĭlova, A; Vodenicharov, E

    1984-01-01

    The experiment was performed 64 albino female rats by a single, intretracheal treatment with 50 mg mine dust. Dynamic biochemical studies were carried out - by 3th and 6th months of the experiment. The data obtained were compared with the changes observed in the positive controls - DQ12 and Ti02 The activity of the oxidation-reduction enzymes and hydrolytic ones was enhanced, the content of sulphhydryl groups and soluble proteins was increased. The results obtained are an evidence of the advancing metabolic disturbances in pulmonary tissue, being better manifested by 6th month of the experiment.

  6. Contamination of benzotriazole ultraviolet stabilizers in house dust from the Philippines: implications on human exposure.

    Science.gov (United States)

    Kim, Joon-Woo; Isobe, Tomohiko; Malarvannan, Govindan; Sudaryanto, Agus; Chang, Kwang-Hyeon; Prudente, Maricar; Tanabe, Shinsuke

    2012-05-01

    Seven compounds of benzotriazole ultraviolet stabilizers (BUVSs) were determined in house dust samples collected from a residential area (Malate: n = 17) and municipal dumping area (Payatas: n = 20) in the Philippines. Total concentrations of the 7 BUVSs in house dust ranged from ND (not detected) to 1020 ng/g in Malate and ND to 277 ng/g in Payatas. Among the target compounds, the most abundant BUVS was UV-234, with a median value of 84 ng/g (ND-813 ng/g) in Malate and 41 ng/g (ND-212 ng/g) in Payatas, respectively. Significantly higher concentrations of UV-326 (p<0.01) and UV-327 (p<0.05) were found in house dust samples from Malate than those from Payatas, suggesting that the household products are the major sources of contamination in the indoor microenvironment. The estimated daily intakes (EDIs) of BUVSs through house dust ingestion in the Philippines were two to four orders of magnitude lower than the guideline values. However, the EDI of 5 BUVSs for toddlers in this study was 5 times higher than those for adults, suggesting that toddlers are at higher risk. House dust may be an important exposure route of UV-234 (88%) and UV-326 (69%) in worst-case scenarios, which using high dust ingestion and worst-case exposure (P95). To our knowledge, this is the first comprehensive study on BUVSs in house dust samples from Asian developing countries and reporting the occurrence of UV-234 and UV-320 in dust samples.

  7. Alcohol Exposure Alters Mouse Lung Inflammation in Response to Inhaled Dust

    Directory of Open Access Journals (Sweden)

    Jill A. Poole

    2012-07-01

    Full Text Available Alcohol exposure is associated with increased lung infections and decreased mucociliary clearance. Occupational workers exposed to dusts from concentrated animal feeding operations (CAFOs are at risk for developing chronic inflammatory lung diseases. Agricultural worker co-exposure to alcohol and organic dust has been established, although little research has been conducted on the combination effects of alcohol and organic dusts on the lung. Previously, we have shown in a mouse model that exposure to hog dust extract (HDE collected from a CAFO results in the activation of protein kinase C (PKC, elevated lavage fluid cytokines/chemokines including interleukin-6 (IL-6, and the development of significant lung pathology. Because alcohol blocks airway epithelial cell release of IL-6 in vitro, we hypothesized that alcohol exposure would alter mouse lung inflammatory responses to HDE. To test this hypothesis, C57BL/6 mice were fed 20% alcohol or water ad libitum for 6 weeks and treated with 12.5% HDE by intranasal inhalation method daily during the final three weeks. Bronchoalveolar lavage fluid (BALF, tracheas and lungs were collected. HDE stimulated a 2–4 fold increase in lung and tracheal PKCε (epsilon activity in mice, but no such increase in PKCε activity was observed in dust-exposed mice fed alcohol. Similarly, alcohol-fed mice demonstrated significantly less IL-6 in lung lavage in response to dust than that observed in control mice instilled with HDE. TNFα levels were also inhibited in the alcohol and HDE-exposed mouse lung tissue as compared to the HDE only exposed group. HDE-induced lung inflammatory aggregates clearly present in the tissue from HDE only exposed animals were not visually detectable in the HDE/alcohol co-exposure group. Statistically significant weight reductions and 20% mortality were also observed in the mice co-exposed to HDE and alcohol. These data suggest that alcohol exposure depresses the ability

  8. Factors Affecting Vegetable Growers’ Exposure to Fungal Bioaerosols and Airborne Dust

    DEFF Research Database (Denmark)

    Hansen, V. M.; Meyling, Nicolai; Winding, Anne;

    2012-01-01

    We have quantified vegetable growers’ exposure to fungal bioaerosol components including (1/3)-b-d-glucan (b-glucan), total fungal spores, and culturable fungal units. Furthermore, we have evaluated factors that might affect vegetable growers’ exposure to fungal bioaerosols and airborne dust....... Investigated environments included greenhouses producing cucumbers and tomatoes, open fields producing cabbage, broccoli, and celery, and packing facilities. Measurements were performed at different times during the growth season and during execution of different work tasks. Bioaerosols were collected...... growth stage of handled plant material, and (iii) open field versus greenhouse significantly affected the workers’ exposure to bioaerosols. Packing of vegetables and working in open fields caused significantly lower exposure to bioaerosols, e.g. mesophilic fungi and dust, than harvesting in greenhouses...

  9. The effect of dust emissions from open storage piles to particle ambient concentration and human exposure.

    Science.gov (United States)

    Chalvatzaki, E; Aleksandropoulou, V; Glytsos, T; Lazaridis, M

    2012-12-01

    The current study focus on the determination of dust emissions from piles in open storage yards of a municipal solid waste (MSW) composting site and the subsequent atmospheric dust dispersion. The ISC3-ST (Industrial Source Complex Version 3 - Short Term) model was used for the evaluation of the PM(10) ambient concentrations associated with the dispersion of MSW compost dust emissions in air. Dust emission rates were calculated using the United States Environmental Protection Agency proposed dust resuspension formulation from open storage piles using local meteorological data. The dispersion modelling results on the spatial distribution of PM(10) source depletion showed that the maximum concentrations were observed at a distance 25-75 m downwind of the piles in the prevailing wind direction. Sensitivity calculations were performed also to reveal the effect of the compost pile height, the friction velocity and the receptor height on the ambient PM(10) concentration. It was observed that PM(10) concentrations (downwind in the prevailing wind direction) increased with increasing the friction velocity, increasing the pile height (for distances greater than 125 m from the source) and decreasing the receptor height (for distances greater than 125 m from the source). Furthermore, the results of ISC3-ST were analysed with the ExDoM (Exposure Dose Model) human exposure model. The ExDoM is a model for calculating the human exposure and the deposition dose, clearance, and finally retention of aerosol particles in the human respiratory tract (RT). PM(10) concentration at the composting site was calculated as the sum of the concentration from compost pile dust resuspension and the background concentration. It was found that the exposure to PM(10) and deposited lung dose for an adult Caucasian male who is not working at the composting site is less by 20-74% and 29-84%, respectively, compared to those for a worker exposed to PM concentrations at the composting site.

  10. Effect of in vivo coal dust exposure on arachidonic acid metabolism in the rat alveolar macrophage

    Energy Technology Data Exchange (ETDEWEB)

    Kuhn, D.C.; Stanley, C.F.; El-Ayouby, N.; Demers, L.M. (Pennsylvania State Univ., Hershey, PA (USA). M.S. Hershey Medical Center, Dept. of Pathology)

    1990-01-01

    Oxygenated metabolites of arachidonic acid (AA) are produced by the alveolar macrophage (AM) and have been shown to mediate inflammatory reactions. We therefore assessed the production of eicosanoids by AM harvested from the lungs of rats exposed to a bituminous coal dust for 2 wk in an inhalation chamber in order to determine if AA metabolism was altered in a manner that may promote an inflammatory response in the lung. Exposure to coal dust resulted in a 66% increase in the number of AM harvested, an increase in thromboxane A{sub 2}(TxA{sub 2}) and leukotriene B{sub 4} (LTB{sub 4}) production to 222% and 181% of control values, respectively, and a decrease in prostaglandin E{sub 2} (PGE{sub 2}) production to 62% of control values. In AM harvested from rats allowed to breathe clean air for 2 wk following coal dust exposure, PGE{sub 2} production returned to control levels but TxA{sub 2} and LTB{sub 4} production remained elevated. The TxA{sub 2} synthesis inhibitor UK 38,485 reduced TxA{sub 2} production in dust-exposed AM both immediately and 2 wk following exposure. Thus, exposure of rats to coal dust significantly alters the metabolism of AA in AM, with potentially important aspects of AA metabolism remaining altered even after a 2-wk recovery period. Based on the established role of eicosanoids in inflammatory and fibrotic processes, these results suggest that the alteration of AM eicosanoid production as a result of the inhalation of coal mine dust may be an important factor in the pathophysiology of coal workers' pneumoconiosis. 26 refs., 4 figs.

  11. Algorithm Research Exposure Dust Emissions Enterprises Of Building Production On The Environment

    Science.gov (United States)

    Omelchenko, E. V.; Trushkova, E. A.; Sidelnikov, M. V.; Pushenko, S. L.; Staseva, E. V.

    2017-01-01

    This paper describes the algorithm research level of exposure to dust emissions, the organization and layout of the sanitary protection zone of the enterprise of building production on the basis of statistical data on emissions share in Russia in the Rostov region, the issues of the impact of harmful substances on the human body and developed measures to reduce air emissions.

  12. [New documentation sheet for medical examination due to exposures to dust].

    Science.gov (United States)

    Hagemeyer, O; Mannes, E; Koppisch, D; Otten, H; Dahmann, D

    2004-05-01

    With beginning of the year 2004 a new documentation sheet for occupational preventive medical examinations according to exposures to mineral dust (quartz, asbestos, ceramic fibres) will replace the existing sheet. The new investigation sheet is presented in this publication and changes are described.

  13. Polybrominated diphenyl ethers (PBDEs) in the indoor dust in China: levels, spatial distribution and human exposure.

    Science.gov (United States)

    Zhu, Ning-Zheng; Liu, Li-Yan; Ma, Wan-Li; Li, Wen-Long; Song, Wei-Wei; Qi, Hong; Li, Yi-Fan

    2015-01-01

    Indoor environment is an important source of human exposure to several toxicants, such as brominated flame retardants. Indoor dust samples were collected in winter season in 2010, which covered 23 provinces across China, for the analysis of polybrominated diphenyl ethers (PBDEs). Concentrations of PBDEs (Σ14PBDEs) ranged from 8.92 to 37,500 ng/g, with the mean of 3520 ng/g. BDE-209 was the most dominate congener, followed by BDE-183, BDE-47 and BDE-99. PBDE concentrations and the longitude were significantly correlated (pPBDEs through dust ingestion and dermal absorption indicated that the toddlers had the highest exposure dose, with the median value of 6.0 ng/kg-bw/day. According to the hazard quotients, health risk of PBDEs via dust ingestion in China is currently acceptable. Monte Carlo simulation was implemented to quantify the uncertainty and sensitivity of exposure models for determining the most influential variables. The results suggested that more specific and accurate parameters should be used for dust ingestion and dermal absorption exposure models in future.

  14. Middle East Desert Dust Exposure: Health Risks from Metals and Microbial Pathogens

    Science.gov (United States)

    Lyles, M. B.

    2014-12-01

    In the Middle East, dust and sand storms are a persistent problem and can deliver significant amounts of micro-particulates via inhalation into the mouth, nasal pharynx, & lungs due to the fine size and abundance of these micro-particulates. The chronic and acute health risks of this dust inhalation have not been well studied nor has the dust been effectively characterized as to its chemical composition, mineral content, or microbial flora. Scientific experiments were designed to study the Kuwaiti and Iraqi dust as to its physical, chemical, and biological characteristics and for its potential to cause adverse health effects. First, dust samples from different locations were collected and processed and exposure data collected. Initial chemical and physical characterization of each sample including particle size distribution and inorganic analysis was conducted, followed by characterization of biologic flora of the dust, including bacteria, fungi and viruses. Data indicates that the mineralized dust is composed of calcium carbonate over a matrix of metallic silicate nanocrystals containing a variety of trace and heavy metals constituting ~3 % of the PM10 particles by weight, of which ~1% is bioaccessible aluminum and reactive iron, each. The particles also consist of ~1% bioavailable aluminum and reactive iron each. Microbial analysis reveals a significant biodiversity of bacterial, fungi, and viruses of which ~30% are known pathogens. Of the microbes identified, several have hemolytic properties and most have significant antibiotic resistance. Viral analysis indicates a tremendous amount of virons with a large percent of RNA viruses. The level of total suspended particle mass at PM 10 along with environmental & physiological conditions present constitute an excessive exposure to micro-particulates including PM 2.5 and the potential for adverse health effects. Reported data on cell culture and animal studies have indicated a high level of toxicity to these dust

  15. Association between environmental dust exposure and lung cancer in dogs.

    Science.gov (United States)

    Bettini, Giuliano; Morini, Maria; Marconato, Laura; Marcato, Paolo Stefano; Zini, Eric

    2010-12-01

    The objective of this study was to investigate the relationship between the accumulation of black dust matter in lungs (anthracosis) and primary lung cancer in dogs. A retrospective study was carried out on material from 35 dogs with primary lung cancer and 160 controls. The amount, histological appearance and birefringence of anthracosis were assessed in pulmonary specimens by light microscopy, and the odds ratio (OR) calculated for dogs with primary lung cancer. The same factors were analysed to identify an association between tumour histotype, histological grade, and clinical stage. Papillary adenocarcinoma was most commonly diagnosed (45.7%). The majority of tumours were of histological grade II, and the lung cancer was more often localised (clinical stage I). An increased risk of lung cancer was observed in dogs with higher amounts of anthracosis (OR: 2.11, CI 95%: 1.20-3.70; P cancer in dogs.

  16. Occupational exposure to wood dust and formaldehyde and risk of nasal, nasopharyngeal, and lung cancer among Finnish men.

    Science.gov (United States)

    Siew, Sie Sie; Kauppinen, Timo; Kyyrönen, Pentti; Heikkilä, Pirjo; Pukkala, Eero

    2012-01-01

    Controversy exists over whether or not occupational inhalation exposure to wood dust and/or formaldehyde increases risk for respiratory cancers. The objective of this study was to examine the risk of nasal, nasopharyngeal, and lung cancer in relation to occupational exposure to wood dust and formaldehyde among Finnish men. The cohort of all Finnish men born between the years 1906 and 1945 and in employment during 1970 was followed up through the Finnish Cancer Registry for cases of cancers of the nose (n = 292), nasopharynx (n = 149), and lung (n = 30,137) during the period 1971-1995. The subjects' occupations, as recorded in the population census in 1970, were converted to estimates of exposure to wood dust, formaldehyde, asbestos, and silica dust through the Finnish job-exposure matrix. Cumulative exposure (CE) was calculated based on the prevalence, average level, and estimated duration of exposure. The relative risk (RR) estimates for the CE categories of wood dust and formaldehyde were defined by Poisson regression, with adjustments made for smoking, socioeconomic status, and exposure to asbestos and/or silica dust. Men exposed to wood dust had a significant excess risk of nasal cancer overall (RR, 1.59; 95% confidence interval [CI], 1.06-2.38), and specifically nasal squamous cell carcinoma (RR, 1.98; 95% CI, 1.19-3.31). Workers exposed to formaldehyde had an RR of 1.18 (95% CI, 1.12-1.25) for lung cancer. There was no indication that CE to wood dust or formaldehyde would increase the risk of nasopharyngeal cancer. Occupational exposure to wood dust appeared to increase the risk of nasal cancer but not of nasopharyngeal or lung cancer. The slight excess risk of lung cancer observed for exposure to formaldehyde may be the result of residual confounding from smoking. In summary, this study provides further evidence that exposure to wood dust in a variety of occupations may increase the risk of nasal cancer.

  17. Exposure assessment to alpha- and beta-pinene, delta(3)-carene and wood dust in industrial production of wood pellets.

    Science.gov (United States)

    Edman, K; Lofstedt, H; Berg, P; Eriksson, K; Axelsson, S; Bryngelsson, I; Fedeli, C

    2003-04-01

    The main aim of the study was to measure the exposure to monoterpenes (alpha- and beta-pinene and Delta(3)-carene) and wood dust during industrial production of wood pellets and briquettes. Additional aims were to compare the results from wood dust sampled on a filter with real time measurements using a direct reading instrument and to identify peak exposures to dust. Twenty-four men working at six companies involved in industrial production of wood pellets and briquettes participated in the study. Monoterpenes were measured by diffusive sampling and wood dust was measured as total dust. A data logger (DataRAM) was used for continuous monitoring of dust concentration for 18 of the participants. The sampling time was approximately 8 h. The personal exposure to monoterpenes ranged from 0.64 to 28 mg/m(3) and a statistically significant (Kruskal-Wallis test, P = 0.0002) difference in levels of monoterpenes for workers at different companies was seen. In the companies the personal exposure to wood dust varied between 0.16 and 19 mg/m(3) and for 10 participants the levels exceeded the present Swedish occupational exposure limit (OEL) of 2 mg/m(3). The levels of wood dust during the morning shift were significantly (Mann-Whitney test, P = 0.04) higher compared with the afternoon shift. Continuous registration of dust concentration showed peak values for several working operations, especially cleaning of truck engines with compressed air. For 24 workers in six companies involved in industrial production of wood pellets the personal exposure to monoterpenes was low and to wood dust high compared with the present Swedish OEL and previous studies in Swedish wood industries. Since the DataRAM can identify critical working tasks with high wood dust exposure a reduction in exposure levels could probably be achieved by changes in working routines and by the use of protective equipment.

  18. Exhaled breath malondialdehyde, spirometric results and dust exposure assessment in ceramics production workers

    Directory of Open Access Journals (Sweden)

    Mohammad Javad Zare Sakhvidi

    2015-02-01

    Full Text Available Introduction The study aimed at measuring exhaled breath malondialdehyde (EBC-MDA in workers exposed to dust containing silica and at its comparison with the non-exposed control group. Material and methods The cross sectional, case-control study (N = 50 was performed in a tile and ceramics production factory in Yazd, Iran. EBC-MDA was quantified in exhaled breath of the participants by a lab made breath sampler. Exposure intensity was measured according to the NIOSH 0600 method in selected homogeneous exposure groups. Additionally, spirometry test was conducted to investigate a correlation between EBC-MDA and spirometric findings in the exposed workers. Results There was no difference in the observed exposure intensities of silica containing dust in different units. However, “coating preparation” was the unit with the highest concentration of dust. Although, the level of EBC-MDA in the cases was slightly higher than in the controls, the difference was not statistically significant (U = 252, p = 0.464. A significant and positive correlation was found between dust exposure intensity in working units and the measured EBC-MDA of workers (r = 0.467, N = 25, p = 0.027. There were also no statistically significant differences among job categories in the exposed group for the values of FEV1% (F(3, 44 = 0.656, p = 0.584, FVC% (F(3, 44 = 1.417, p = 0.172, and FEV1/FVC% (F(3, 44 = 1.929, p = 0.139. Conclusions The results showed a significant correlation between respirable dust exposure intensity and the level of EBC-MDA of the exposed subjects. However, our results did not show a significant correlation between lung function decreases and EBC-MDA.

  19. Evaluation of Occupational Exposure and Biological Monitoring of Sand Washing Workers Exposed to Silica Dusts

    Directory of Open Access Journals (Sweden)

    Gholamreza Parsaseresht

    2017-01-01

    Full Text Available Background and Objectives:The health of sand washing workers could be threatened by the crystalline silica dust exposure. The aim of this study was the evaluation of occupational and biological monitoring with crystalline silica dusts in the sand washing workers. Materials and Methods: This was an analytical and cross-sectional study of 44 sand washing workers exposed to crystalline silica and also 63 municipality gardeners as a control group in the city of Dorood. Occupational exposure monitoring to respirable total dust and silica dust was performed according to the National Institute for Occupational Safety and Health (NIOSH methods 0600 and 7602-respectively. Biological monitoring of workers' was carried out according to the Karatas method for the analysis of Malondialdehyde in the blood serum of exposed and control subjects. The informed consents were taken for obtaining blood samples of workers, according to the Helsinki Declaration. Statistical analysis of data was done using SPSS version 16. The statistical test of Pearson, t-tests and linear regression was applied. Results: The occupational exposure of 54.55% was exceeded the occupational exposure limit of Iran at the level of 3 mg/m3. The mean exposure of sand miners and control group to respirable silica dust was evaluated at 0.219 ± 0.177 and 0.010 ± 0.002 as mg/m3respectively. Occupational exposure of all sand washing workers was higher than the occupational exposure limit of Iran at the level of 0.025 mg/m3.The concentration of serum Malondialdehyde (MDA exposed group and the control group were 36.64 ± 10.75 and 19.40 ± 4.68 as µM respectively. Conclusion: Due to the positive correlation between exposure of sand washing workers to silica dust sand serum MDA among exposed group(P-value<0.0001, r=0.881, periodical biological monitoring along with effective control measures of workers are recommended for the health promotion of these workers.

  20. Phthalates in dormitory and house dust of northern Chinese cities: Occurrence, human exposure, and risk assessment.

    Science.gov (United States)

    Li, Hai-Ling; Song, Wei-Wei; Zhang, Zi-Feng; Ma, Wan-Li; Gao, Chong-Jing; Li, Jia; Huo, Chun-Yan; Mohammed, Mohammed O A; Liu, Li-Yan; Kannan, Kurunthachalam; Li, Yi-Fan

    2016-09-15

    Phthalates are widely used chemicals in household products, which severely affect human health. However, there were limited studies emphasized on young adults' exposure to phthalates in dormitories. In this study, seven phthalates were extracted from indoor dust that collected in university dormitories in Harbin, Shenyang, and Baoding, in the north of China. Dust samples were also collected in houses in Harbin for comparison. The total concentrations of phthalates in dormitory dust in Harbin and Shenyang samples were significantly higher than those in Baoding samples. The total geometric mean concentration of phthalates in dormitory dust in Harbin was lower than in house dust. Di-(2-ethylhexyl) phthalate (DEHP) was the most abundant phthalate in both dormitory and house dust. The daily intakes of the total phthalates, carcinogenic risk (CR) of DEHP, hazard index (HI) of di-isobutyl phthalate (DiBP), dibutyl phthalate (DBP), and DEHP were estimated, the median values for all students in dormitories were lower than adults who live in the houses. Monte Carlo simulation was applied to predict the human exposure risk of phthalates. HI of DiBP, DBP, and DEHP was predicted according to the reference doses (RfD) provided by the United States Environmental Protection Agency (U.S.EPA) and the reference doses for anti-androgenicity (RfD AA) developed by Kortenkamp and Faust. The results indicated that the risks of some students had exceeded the limitation, however, the measured results were not exceeded the limitation. Risk quotients (RQ) of DEHP were predicted based on China specific No Significant Risk Level (NSRL) and Maximum Allowable Dose Level (MADL). The predicted results of CR and RQ of DEHP suggested that DEHP could pose a health risk through intake of indoor dust.

  1. An analysis of employee exposure to organic dust at large-scale composting facilities

    Science.gov (United States)

    Sykes, P.; Allen, J. A.; Wildsmith, J. D.; Jones, K. P.

    2009-02-01

    The occupational health implications from exposure to dust, endotoxin and 1-3 β Glucan at commercial composting sites are uncertain. This study aims to establish employee exposure levels to inhalable and respirable dust, endotoxin and 1-3 β Glucan during various operational practices in the composting process. Personal samples were collected and the inhalable and respirable dust fractions were determined by gravimetric analysis. Endotoxin concentrations were determined using a Limulus Amebocyte Lysate assay (LAL). 1-3 β Glucan levels were estimated using a specific blocking agent to establish the contribution that these compounds gave to the original endotoxin assay. Employees' exposure to dust was found to be generally lower than the levels stipulated in the Control of Substances Hazardous to Health Regulations (COSHH) 2002 (as amended), (median inhalable fraction 1.08 mg/m3, min 0.25 mg/m3 max 10.80 mg/m3, median respirable fraction 0.05 mg/m3, min 0.02 mg/m3, max 1.49 mg/m3). Determination of the biological component of the dust showed that employees' exposures to endotoxin were elevated (median 31.5 EU/m3, min 2.00 EU/m3, max 1741.78 EU/m3), particularly when waste was agitated (median 175.0 EU/m3, min 2.03 EU/m3, max 1741.78 EU/m3). Eight out of 32 (25%) of the personal exposure data for endotoxin exceeded the 200 EU/m3 temporary legal limit adopted in the Netherlands and thirteen out of 32 (40.6%) exceeded the suggested 50 EU/m3 guidance level suggested to protect workers from respiratory health effects. A significant correlation was observed between employee inhalable dust exposure and personal endotoxin concentration (r = 0.728, pdisease mechanisms are not well understood at this present time. Consequently, in light of this uncertainty, it is recommended that a precautionary approach be adopted in managing the potential health risks associated with inhalation of organic dusts at composting sites.

  2. Exposure to wood dust and heavy metals in workers using CCA pressure-treated wood.

    Science.gov (United States)

    Decker, Paul; Cohen, Beverly; Butala, John H; Gordon, Terry

    2002-01-01

    Chemical pesticide treatment enables relatively nonresistant woods to be used in outdoor construction projects. The most prevalent procedure used to protect these woods is pressure treatment with chromium, copper, and arsenic (CCA). This pilot study examined the airborne concentration and particle size distribution of wood particles, chromium, copper, and arsenic at both outdoor (measured over the whole work day) and indoor (measured during the performance of specific tasks) work sites. At the outdoor residential deck construction sites, the arithmetic mean total dust concentration, measured using personal filter cassette samplers, was 0.57 mg/m3. The mass median aerodynamic diameter (da) of the outdoor wood dust was greater than 20 microm. Indoor wood dust concentrations were significantly greater than those measured outdoor and were job category-dependent. The highest mean breathing zone dust concentration, 49.0 mg/m3, was measured at the indoor sanding operation. Personal impactor sampling demonstrated that the mean total airborne concentration of arsenic, but not chromium or copper, was consistently above recommended occupational exposure levels at the indoor work site, and occasionally at the outdoor work sites. At the indoor sanding operation, the mean total chromium, copper, and arsenic concentrations were 345, 170, and 342 microg/m3, respectively. Thus, significant exposure to airborne heavy metals can occur as a result of indoor and outdoor exposure to CCA pressure-treated wood dust. Therefore, current standards for wood dust may not adequately protect workers from the heavy metals commonly used in CCA pressure-treated wood.

  3. An analysis of employee exposure to organic dust at large-scale composting facilities

    Energy Technology Data Exchange (ETDEWEB)

    Sykes, P; Allen, J A; Wildsmith, J D; Jones, K P, E-mail: psykes@uwic.ac.u [University of Wales Institute Cardiff (UWIC), Cardiff School of Health Sciences, Western Avenue, Cardiff, CF5 2YB (United Kingdom)

    2009-02-01

    The occupational health implications from exposure to dust, endotoxin and 1-3 beta Glucan at commercial composting sites are uncertain. This study aims to establish employee exposure levels to inhalable and respirable dust, endotoxin and 1-3 beta Glucan during various operational practices in the composting process. Personal samples were collected and the inhalable and respirable dust fractions were determined by gravimetric analysis. Endotoxin concentrations were determined using a Limulus Amebocyte Lysate assay (LAL). 1-3 beta Glucan levels were estimated using a specific blocking agent to establish the contribution that these compounds gave to the original endotoxin assay. Employees' exposure to dust was found to be generally lower than the levels stipulated in the Control of Substances Hazardous to Health Regulations (COSHH) 2002 (as amended), (median inhalable fraction 1.08 mg/m{sup 3}, min 0.25 mg/m{sup 3} max 10.80 mg/m{sup 3}, median respirable fraction 0.05 mg/m{sup 3}, min 0.02 mg/m{sup 3}, max 1.49 mg/m{sup 3}). Determination of the biological component of the dust showed that employees' exposures to endotoxin were elevated (median 31.5 EU/m{sup 3}, min 2.00 EU/m{sup 3}, max 1741.78 EU/m{sup 3}), particularly when waste was agitated (median 175.0 EU/m{sup 3}, min 2.03 EU/m{sup 3}, max 1741.78 EU/m{sup 3}). Eight out of 32 (25%) of the personal exposure data for endotoxin exceeded the 200 EU/m{sup 3} temporary legal limit adopted in the Netherlands and thirteen out of 32 (40.6%) exceeded the suggested 50 EU/m{sup 3} guidance level suggested to protect workers from respiratory health effects. A significant correlation was observed between employee inhalable dust exposure and personal endotoxin concentration (r = 0.728, p<0.05) and also personal endotoxin exposure and 1-3 beta Glucan concentration (r = 0.817, p<0.05). Further work is needed to explore the possibility of using inhalable dust concentration as a predictor for personal endotoxin

  4. A case-control study of wood dust exposure, mutagen sensitivity, and lung cancer risk.

    Science.gov (United States)

    Wu, X; Delclos, G L; Annegers, J F; Bondy, M L; Honn, S E; Henry, B; Hsu, T C; Spitz, M R

    1995-09-01

    The associations between lung cancer risk, mutagen sensitivity (a marker of cancer susceptibility), and a putative lung carcinogen, wood dust, were assessed in a hospital-based case-control study. There were 113 African -American and 67 Mexican-American cases with newly diagnosed, previously untreated lung cancer and 270 controls, frequency-matched on age, ethnicity, and sex. Mutagen sensitivity ( 1 chromatid break/cell after short-term bleomycin treatment) was associated with statistically significant elevated risk for lung cancer [odds ration (OR) = 4.3; 95% confidence intervals (CI) = 2.3-7.9]. Wood dust exposure was also a significant predictor of risk (overall OR = 3.5; CI = 1.4-8.6) after controlling for smoking and mutagen sensitivity. When stratified by ethnicity, wood dust exposure was s significant risk factor for African-Americans (OR = 5.5; CI = 1.6-18.9) but not for Mexican-Americans (OR = 2.0; CI = 0.5-8.1). The ORs were 3.8 and 4.8 for non-small cell lung cancer in Mexican-Americans (CI = 1.2-18.5). Stratified analysis suggested evidence of strong interactions between wood dust exposure and both mutagen sensitivity and smoking in lung cancer risk.

  5. [Indoor dust as a pathway of human exposure to polybrominated diphenyl ethers (PBDEs)].

    Science.gov (United States)

    Góralczyk, Katarzyna; Struciński, Paweł; Hernik, Agnieszka; Czaja, Katarzyna; Korcz, Wojciech; Minorczyk, Maria; Ludwicki, Jan K

    2012-01-01

    The brominated diphenyl ethers (PBDEs) belong to a class of synthetic, additive brominated flame retardants (BFRs). PBDEs are used to reduce the flammability of commercial and household products such as textiles, various plastic polymers, furnishing foam, and electronic equipment. People spend a large percentage of their life-time indoors at home, in offices and cars, etc, providing many opportunities for lengthy exposure to PBDEs from residential settings and commercial products in an indoor environment. In recent time, the foodstuffs, mainly food of animal origin, have been indicated as the main pathway of human exposure to PBDEs. However, many studies have shown that the indoor environment, mainly indoor dust, can be also a significant source of exposure to PBDEs, especially for younger children (toddlers) because of their behavioral patterns, eg. putting fingers, toys, and other items in their mouth. Numerous studies show that the median intakes of PBDEs via dust for adult range from 1.41 to 277 ng x day(-1) is lower than that via food which range from 135 to 333 ng x day-', while the median intake of these compounds via indoor dust for children range from 101 to 404 ng x day(-1) is much higher than via food: 77-190 ng x day(-1). The congener pattern observed in the indoor dust is different to that found in food. The indoor dust is dominated by the congener BDE-209 vs. food where the most dominated congeners are BDE-47 and BDE-99. Human exposure to PBDEs and other brominated flame retardants (BFRs) is widely widespread throughout the world and it depends on a country range of usage, production and legislation concerning these chemicals as well as a citizen's behavior. Generally, human exposure has been found higher in North America than in Europe and Asia. Within European countries the significant highest concentrations in dust have been found in the United Kingdom. It should be noted that many uncertainty factors such as personal habits, dietary preferences

  6. 75 FR 64411 - Lowering Miners' Exposure to Respirable Coal Mine Dust, Including Continuous Personal Dust Monitors

    Science.gov (United States)

    2010-10-19

    ... during the entire time that a miner works to account for shifts longer than 8 hours (hr); (4) requiring... number assigned by MSHA. The proposal would be consistent with the existing practice of identifying DAs... hygiene practices that adjust worker exposures to account for all time worked, recognizing that...

  7. Chronic Lunar Dust Exposure on Rat Cornea: Evaluation by Gene Expression Profiling

    Science.gov (United States)

    Theriot, C. A.; Glass, A.; Lam, C-W.; James, J.; Zanello, S. B.

    2014-01-01

    Lunar dust is capable of entering habitats and vehicle compartments by sticking to spacesuits or other objects that are transferred into the spacecraft from the lunar surface and has been reported to cause irritation upon exposure. During the Apollo missions, crewmembers reported irritation specifically to the skin and eyes after contamination of the lunar and service modules. It has since been hypothesized that ocular irritation and abrasion might occur as a result of such exposure, impairing crew vision. Recent work has shown that both ultrafine and unground lunar dust exhibited minimal irritancy of the ocular surface (i.e., cornea); however, the assessment of the severity of ocular damage resulting from contact of lunar dust particles to the cornea has focused only on macroscopic signs of mechanical irritancy and cytotoxicity. Given the chemical reactive properties of lunar dust, exposure of the cornea may contribute to detrimental effects at the molecular level including but not limited to oxidative damage. Additionally, low level chronic exposures may confound any results obtained in previous acute studies. We report here preliminary results from a tissue sharing effort using 10-week-old Fischer 344 male rats chronically exposed to filtered air or jet milled lunar dust collected during Apollo 14 using a Jaeger-NYU nose-only chamber for a total of 120 hours (6 hours daily, 5 days a week) over a 4-week period. RNA was isolated from corneas collected from rats at 1 day and 7 days after being exposed to concentrations of 0, 20, and 60 mg/m3 of lunar dust. Microarray analysis was performed using the Affymetrix GeneChip Rat Genome 230 2.0 Array with Affymetrix Expression Console and Transcriptome Analysis Console used for normalization and secondary analysis. An Ingenuity iReport"TM" was then generated for canonical pathway identification. The number of differentially expressed genes identified increases with dose compared to controls suggesting a more severe

  8. Histological changes in the nasal mucosa in rats after long-term exposure to formaldehyde and wood dust.

    Science.gov (United States)

    Holmström, M; Wilhelmsson, B; Hellquist, H

    1989-01-01

    Wood dust is a well known nasal carcinogen in man, as formaldehyde is in rats. In certain occupational environments, combined exposure to wood dust and formaldehyde is common. Little is known about the effects of this combination. A pilot study was performed on four groups of Sprague-Dawley rats: one exposed to wood dust (25 mg/m3), another to formaldehyde (12.4 ppm) and a third to both wood dust and formaldehyde; the fourth group served a control group. After 104 weeks of exposure the nose and lungs were examined histologically. One well differentiated squamous cell carcinoma was found in the formaldehyde group. Squamous cell metaplasia was found significantly more often among the formaldehyde-exposed rats. Squamous cell metaplasia with dysplasia was most frequently observed, however, in the group exposed to both formaldehyde and wood dust. There were also significantly more rats with pulmonary emphysema in the groups exposed to wood dust than in the other groups.

  9. Exposure to house dust phthalates in relation to asthma and allergies in both children and adults.

    Science.gov (United States)

    Ait Bamai, Yu; Shibata, Eiji; Saito, Ikue; Araki, Atsuko; Kanazawa, Ayako; Morimoto, Kanehisa; Nakayama, Kunio; Tanaka, Masatoshi; Takigawa, Tomoko; Yoshimura, Takesumi; Chikara, Hisao; Saijo, Yasuaki; Kishi, Reiko

    2014-07-01

    Although an association between exposure to phthalates in house dust and childhood asthma or allergies has been reported in recent years, there have been no reports of these associations focusing on both adults and children. We aimed to investigate the relationships between phthalate levels in Japanese dwellings and the prevalence of asthma and allergies in both children and adult inhabitants in a cross-sectional study. The levels of seven phthalates in floor dust and multi-surface dust in 156 single-family homes were measured. According to a self-reported questionnaire, the prevalence of bronchial asthma, allergic rhinitis, allergic conjunctivitis, and atopic dermatitis in the 2 years preceding the study was 4.7%, 18.6%, 7.6%, and 10.3%, respectively. After evaluating the interaction effects of age and exposure categories with generalized liner mixed models, interaction effects were obtained for DiNP and bronchial asthma in adults (Pinteraction=0.028) and for DMP and allergic rhinitis in children (Pinteraction=0.015). Although not statistically significant, children had higher ORs of allergic rhinitis for DiNP, allergic conjunctivitis for DEHP, and atopic dermatitis for DiBP and BBzP than adults, and liner associations were observed (Ptrendphthalates levels collected from multi-surfaces. This study suggests that the levels of DMP, DEHP, DiBP, and BBzP in floor dust were associated with the prevalence of allergic rhinitis, conjunctivitis, and atopic dermatitis in children, and children are more vulnerable to phthalate exposure via household floor dust than are adults. The results from this study were shown by cross-sectional nature of the analyses and elaborate assessments for metabolism of phthalates were not considered. Further studies are needed to advance our understanding of phthalate toxicity.

  10. Lung fibrosis and exposure to wood dusts: Two cases report and review of the literature

    Directory of Open Access Journals (Sweden)

    Matteo Riccò

    2015-10-01

    Full Text Available Introduction: Increasing evidence suggests that idiopathic pulmonary fibrosis (IPF occurs more often in subjects previously exposed to wood dusts than in non-exposed subjects. Here we report 2 cases of the IPF among workers prolongedly exposed to high levels of hardwood dusts. Case report: The case No. 1: An 83 year-old male former smoker, retired joiner developed mild dyspnoea and chronic dry cough over the period preceding the examination. Pulmonary function tests (PFT identified a mild restrictive pattern and diffusion capacity for carbon dioxide (CO2 that was severely impaired (57% of predicted value. High resolution computer tomography (HRCT identified bilateral, subpleural basal reticular opacities in honeycombing, without any nodules or ground-glass opacities. The case No. 2: A 73 year-old male retired joiner, never smoker, presented a 3-year history of progressive breathlessness and non-productive cough in mild hypoxemia. Pulmonary function tests suggested a moderate restrictive pattern in severely impaired diffusion capacity for CO2 (54% of predicted value. High resolution computer tomography identified diffuse peripheral reticular opacities and honeycombing of lower fields, with apico-basilar gradient. Both cases received diagnosis of the idiopathic pulmonary fibrosis. Discussion: The pulmonary fibrosis is a common feature of several diseases and may be induced by inflammatory disorders following inhalation of organic and inorganic dusts (e.g., asbestos, silica, and several reports suggest that many cases of the IPF may be in fact secondary to occupational dust exposure as in the case reports we present here. Conclusions: Occupational exposure to wood dusts may be a risk factor for the IPF. Unfortunately, exposure reconstruction is frequently inconsistent and anamnesis often misses other causes of the pulmonary fibrosis (e.g., extrinsic allergic alveolitis. Med Pr 2015;66(5:739–747

  11. Occupational exposure to wood dust in the british woodworking industry in 1999/2000.

    Science.gov (United States)

    Black, Nigel; Dilworth, Martin; Summers, Nick

    2007-04-01

    Exposure to inhalable wood dust and compliance with the British Control of Substances Hazardous to Health (COSHH) Regulations 1999 were assessed at a representative cross-section of the British woodworking industry. Median exposures ranged from 1.5 to 2.8 mg/m(3) across the selected industry groups, the lowest being in sawmilling and planing of wood. Overall, 27% of values exceeded the maximum exposure limit (MEL) at that time of 5 mg/m(3). These results showed that the percentage of exposures above the MEL was less than in a survey carried out 10 years earlier. A wide variation of exposures was identified at different machines and tasks. At least 90% at bandsawing and cross-cut sawing were woodworking activities.

  12. Impact of Direct Soil Exposures from Airborne Dust and Geophagy on Human Health

    Directory of Open Access Journals (Sweden)

    Charles F. Sing

    2010-03-01

    Full Text Available Over evolutionary time humans have developed a complex biological relationship with soils. Here we describe modes of soil exposure and their biological implications. We consider two types of soil exposure, the first being the continuous exposure to airborne soil, and the second being dietary ingestion of soils, or geophagy. It may be assumed that airborne dust and ingestion of soil have influenced the evolution of particular DNA sequences which control biological systems that enable individual organisms to take advantage of, adapt to and/or protect against exposures to soil materials. We review the potential for soil exposure as an environmental source of epigenetic signals which may influence the function of our genome in determining health and disease.

  13. Variations in exposure to inhalable wood dust in the Danish furniture industry. Within- and between-worker and factory components estimated from passive dust sampling.

    Science.gov (United States)

    Vinzents, P S; Schlünssen, V; Feveile, H; Schaumburg, I

    2001-10-01

    Variability of exposure to wood dust at large factories in the Danish furniture industry was studied. Three repeated exposure measurements of 292 workers at 38 factories were included in the study. The measurements were carried out by use of personal passive dust monitors. The components of variance were estimated by means of a random effects ANOVA model. The ratio of within- to between-worker variance was 1.07. Based on this result, and three repeated exposure measurements, the observed relation between health outcome and exposure will be attenuated to 74% of the true value. Grouping by factory showed very poor exposure contrast, as the contrast in exposure level among factories was as low as 0.15.

  14. Indoor and outdoor dust in Damaturu Nigeria : composition, exposure and risk to human health

    OpenAIRE

    Mohammed, Fatima Sule

    2013-01-01

    Harmattan and Dust (sand) storms together with anthropogenic activities including the use of firewood and kerosene as fuel for cooking, and diesel/petrol generators for electricity generation are potential sources of particulate and gaseous pollutants in homes in Damaturu town, Nigeria. Other activities like the burning of locally produced incense and mosquito coils as well as the use of aerosol sprays are further possible sources of indoor pollution, which may result in exposure of people to...

  15. Investigation into the use of cement kiln dust in high density sludge (HDS) treatment of acid mine water.

    Science.gov (United States)

    Mackie, Allison L; Walsh, Margaret E

    2015-11-15

    The purpose of this study was to investigate the potential to replace lime with cement kiln dust (CKD) in high density sludge (HDS) treatment of acid mine drainage (AMD). The bench-scale study used two water samples: AMD sampled from a lead-zinc mine with high concentrations of iron (Fe), zinc (Zn), and arsenic (As) (Fe/Zn-AMD) and a synthetic AMD solution (Syn-AMD) spiked with ferric sulfate (Fe2(SO4)3). Arsenic was found to be significantly reduced with CKD-HDS treatment of Fe/Zn-AMD compared to lime-HDS treatment, to concentrations below the stringent mine effluent discharge regulation of 0.10 mg As/L (i.e., 0.04 ± 0.02 mg/L). Both CKD- and lime-HDS treatment of the two AMD samples resulted in settled water Fe concentrations above the stringent discharge guideline of 0.3 mg Fe/L. CKD addition in the HDS process also resulted in high settled water turbidity, above typical discharge guidelines of 15 mg TSS/L. CKD-HDS treatment was found to result in significantly improved settled solids (i.e., sludge) quality compared to that generated in the lime-HDS process. HDS treatment with CKD resulted in 25-88% lower sludge volume indices, 2 to 9 times higher % wet solids, and 10 to 20 times higher % dry solids compared to lime addition. XRD and XPS testing indicated that CKD-HDS sludge consisted of mainly CaCO3 and SiO2 with Fe(3+) precipitates attached at particle surfaces. XRD and XPS testing of the lime-HDS generated sludge showed that it consisted of non-crystalline Fe oxides typical of sludge formed from precipitates with a high water concentration. Increased sedimentation rates were also found for CKD (1.3 cm/s) compared to lime (0.3 cm/s). The increased solids loading with CKD addition compared to lime addition in the HDS process was suggested to both promote surface complexation of metal precipitates with insoluble CKD particles and increase compression effects during Type IV sedimentation. These mechanisms collectively contributed to the reduced water content of

  16. Risk assessments of PAHs and Hg exposure via settled house dust and street dust, linking with their correlations in human hair.

    Science.gov (United States)

    Wang, Wei; Wu, Fuyong; Zheng, Jinshu; Wong, Ming Hung

    2013-12-15

    Domestic energy, chemicals bioaccessibility and particle size were found as three critical factors for risk assessment of PAHs exposure via settled house dust (SHD) and street dust. ∑PAHs and Hg contained in SHD were significantly (p10(-4)) via SHD exposure. The highest accumulation trend of PAHs and Hg were found in PAHs led to a significant decrease on related cancer risks and decreased in the order of 1.9, 1.1, 0.6 and 0.4 μg g(-1) with the increase of particle sizes (PAHs (0.05-0.9 μg g(-1)) and Hg (0.04-1.6 μg g(-1)). Different PAHs profiles were found between PAHs in SHD and those of hair, indicating that exogenous exposure to PAHs adsorbed on dust was not the major source of hair PAHs.

  17. Phthalates in indoor dust in Kuwait: implications for non-dietary human exposure.

    Science.gov (United States)

    Gevao, B; Al-Ghadban, A N; Bahloul, M; Uddin, S; Zafar, J

    2013-04-01

    Phthalates are semivolatile organic compounds with a ubiquitous environmental distribution. Their presence in indoor environments is linked to their use in a variety of consumer products such as children's toys, cosmetics, food packaging, flexible PVC flooring among others. The goal of this study was to investigate the occurrence and concentration of phthalates in dust from homes in Kuwait and to assess non-dietary human exposure to these phthalates. Dust samples were randomly collected from 21 homes and analyzed for eight phthalates. The concentrations of total phthalates were log normally distributed and ranged from 470 to 7800 μg/g. Five phthalates [Di(2-ethylhexyl) phthalate (DEHP), Di-n-octyl phthalate (DnOP), Di-n-butyl phthalate (DBP), Benzyl butyl phthalate (BzBP), and Dicyclohexyl phthalate (DcHP)] were routinely detected. The major phthalate compound was DEHP at a geometric mean concentration of 1704 μg/g (median, 2256 μg/g) accounting for 92% of the total phthalates measured. Using the measured concentrations and estimates of dust ingestion rates for children and adults, estimated human non-dietary exposure based on median phthalate concentrations ranged from 938 ng/kg-bd/day for adults to 13362 ng/kg-bd/day for toddlers. The difference in exposure estimates between children and adults in this study supports previous reports that children are at greater risk from pollutants that accumulate indoors.

  18. Non-malignant respiratory diseases and occupational exposure to wood dust. Part I. Fresh wood and mixed wood industry.

    Science.gov (United States)

    Jacobsen, Gitte; Schaumburg, Inger; Sigsgaard, Torben; Schlunssen, Vivi

    2010-01-01

    This paper reviews associations in literature between exposure to wood dust from fresh wood and non-malignant respiratory diseases. Criteria for inclusion are epidemiological studies in English language journals with an internal or external control group describing relationships between wood dust exposure and respiratory diseases or symptoms. The papers took into account smoking, and when dealing with lung function took age into consideration. A total of 25 papers concerning exposure to fresh wood and mixed wood formed the basis of this review. The results support an association between fresh wood dust exposure and asthma, asthma symptoms, coughing, bronchitis, and acute and chronic impairment of lung function. In addition, an association between fresh wood dust exposure and rhino-conjunctivitis was seen across studies. Apart from plicatic acid in western red cedar wood, no causal agent was consistently disclosed. Type 1 allergy is not suspected of being a major cause of wood dust induced asthma. Concurrent exposure to microorganisms and terpenes probably add to the inherent risk of wood dust exposure in the fresh wood industry.

  19. Cause-specific mortality in British coal workers and exposure to respirable dust and quartz

    Energy Technology Data Exchange (ETDEWEB)

    Miller, B.G.; MacCalman, L. [Institute of Occupational Medicine, Edinburgh (United Kingdom)

    2010-04-15

    In the 1950s the Pneumoconiosis Field Research (PFR) programme was set up to study the health of British coal workers. Studies included regular health surveys, an intensive characterisation of workers' individual exposures, and entry to a cohort followed up to the present for cause-specific mortality. This study reports on analyses of cause-specific mortality in a cohort of almost 18 000 men from 10 British collieries. External analyses used standardised mortality ratios (SMRs), comparing observed mortality with reference rates from the regions in which the collieries were situated. Causes investigated include lung and stomach cancers, chronic obstructive pulmonary disease and cardiovascular endpoints. Internal analyses used Cox regression models with time-dependent exposures adjusting for the confounding effects of age, smoking, cohort entry date and regional differences in population mortality rates. Several causes showed evidence of a healthy worker effect early in the follow-up, with a deficit in the SMR diminishing over time. For most of the causes there was a significant excess in the latter part of follow-up. Internal analyses found evidence of an association between increased risks of lung cancer and increased quartz exposure, particularly at a lag of 15 years. Risks of mortality from non-malignant respiratory disease showed increases with increased exposure to respirable dust. This paper adds to the evidence on the long-term effects of exposure to coalmine dust on mortality from respiratory diseases.

  20. Cause-specific mortality in British coal workers and exposure to respirable dust and quartz

    Energy Technology Data Exchange (ETDEWEB)

    Brian G Miller; Laura MacCalman [Institute of Occupational Medicine, Edinburgh (United Kingdom)

    2010-04-15

    In the 1950s the Pneumoconiosis Field Research (PFR) programme was set up to study the health of British coal workers. Studies included regular health surveys, an intensive characterisation of workers' individual exposures, and entry to a cohort followed up to the present for cause-specific mortality. This study reports on analyses of cause-specific mortality in a cohort of almost 18?000 men from 10 British collieries. External analyses used standardised mortality ratios (SMRs), comparing observed mortality with reference rates from the regions in which the collieries were situated. Causes investigated include lung and stomach cancers, chronic obstructive pulmonary disease and cardiovascular endpoints. Internal analyses used Cox regression models with time-dependent exposures adjusting for the confounding effects of age, smoking, cohort entry date and regional differences in population mortality rates. Several causes showed evidence of a healthy worker effect early in the follow-up, with a deficit in the SMR diminishing over time. For most of the causes there was a significant excess in the latter part of follow-up. Internal analyses found evidence of an association between increased risks of lung cancer and increased quartz exposure, particularly at a lag of 15 years. Risks of mortality from non-malignant respiratory disease showed increases with increased exposure to respirable dust. This paper adds to the evidence on the long-term effects of exposure to coalmine dust on mortality from respiratory diseases.

  1. Brominated and organophosphate flame retardants in indoor dust of Jeddah, Kingdom of Saudi Arabia: Implications for human exposure.

    Science.gov (United States)

    Ali, Nadeem; Eqani, Syed Ali Musstjab Akber Shah; Ismail, Iqbal Mohammad Ibrahim; Malarvannan, Govindan; Kadi, Mohammad W; Albar, Hussain Mohammed Salem; Rehan, Mohammad; Covaci, Adrian

    2016-11-01

    Different flame retardants (FRs) namely polybrominated diphenyl ethers (PBDEs), emerging brominated/chlorinated flame retardants (Br/Cl FRs), and organophosphate FRs (OPFRs) were analyzed in cars, air conditioner (AC) filters and floor dust of different households from Jeddah, Kingdom of Saudi Arabia (KSA). To the best of our knowledge, this is first study in literature reporting emerging Br/Cl FRs and OPFRs in AC filter dust and also first to report on their occurrence in dust from KSA. Chlorinated alkyl phosphate, penta-BDEs, BDE-209, and decabromodiphenylethane (DBDPE) were the major chemicals in dust samples from all microenvironments. ΣOPFRs occurred at median concentrations (ng/g dust) of 15,400, 10,500, and 3750 in AC filter, car and house floor dust, respectively. For all analyzed chemicals, relatively lower levels were observed in floor dust than car and AC filter dust. The profiles of FRs in car dust were different from AC filter and floor dust, which reflected their wider application as FR and plasticizer in variety of household and commercial products. For toddlers, assuming high dust intake and 95th percentile concentrations, the computed exposure estimation for BDE-99 was higher than RfD values.

  2. A 20-year follow-up study on the effects of long-term exposure to thorium dust

    Institute of Scientific and Technical Information of China (English)

    陈兴安; 程永娥; 肖慧娟; 冯国栋; 邓芸辉; 冯志良; 陈莲; 韩轩茂; 杨英杰; 董智华; 甄荣

    2003-01-01

    Objective The purpose of this study is to investigate the possible effects of long-term exposure to dust containing thorium and thoron progeny dust-exposed miners. Methods A negative, high voltage, exhaled thoron progeny measurement system was used to estimate the miners' thorium lung burden. Results The highest thorium lung burden of 638 miners was 11.11 Bq. The incidence of stage 0+ pneumoconiosis was higher among dust-exposed miners. Lung cancer mortality of the dust-exposed miners was significantly higher than that of controls (P<0.005). Conclusion There is a difference in cancer rates between those who have long-term exposure to dust containing thorium (in which carcinogenic ThO2 and SiO2 exist) and thoron progeny and those who have not.

  3. Cotton Dust Exposure and Resulting Respiratory Disorders Among Home-Based Garment Workers.

    Science.gov (United States)

    Silpasuwan, Pimpan; Prayomyong, Somchit; Sujitrat, Dusit; Suwan-Ampai, Plernpit

    2016-03-01

    Cotton dust exposures and resulting respiratory disorders among Thai home-based garment workers in Bangkok were explored. Structured interviews focused on occupational health assessments of respiratory disorders; workflow process observations, lung function screening tests, and garment dust density assessments were used to gather data. Results revealed that garment workers in this study had worked in home-based tailoring an average of 14.88 years; 88.5% reported average health status, only 2.6% currently smoked cigarettes, and 8.6% had impaired lung function. The prevalence of respiratory disorders in this occupational group was 25%. Significant respiratory tract signs and symptoms were associated with lung function capacity (odds ratio [OR] = 52.15, 95% confidence interval [CI] = [6.49, 419.60]). Long work hours and few preventive behaviors were significantly associated with respiratory disorders (OR = 2.89 and OR = 10.183, respectively). Improving working conditions at home and minimizing fabric dust exposure among garment workers are recommended.

  4. Occupational health risk assessment and exposure to floor dust PAHs inside an educational building.

    Science.gov (United States)

    Maragkidou, Androniki; Arar, Sharif; Al-Hunaiti, Afnan; Ma, Yuning; Harrad, Stuart; Jaghbeir, Omar; Faouri, Dina; Hämeri, Kaarle; Hussein, Tareq

    2017-02-01

    Polycyclic aromatic hydrocarbons (PAHs) settled in floor dust play an important role in human health. Although many studies investigated occupational exposure to PAHs, no attempts have been made to report PAHs concentrations as well as their health risk assessment inside an educational building in Jordan. Therefore, the main objective of this study is to report the PAHs concentrations in floor dust and evaluate their exposure and health risk inside the Department of Physics of the University of Jordan. The total PAHs concentrations ranged from 714 to 5246ng/g. The high concentrations were observed inside some offices, where tobacco smoking took place. One of those offices was previously renovated and some petrochemical liquids were used to remove the remaining glue from a previous carpet. Interestingly, the PAHs inside these offices were higher than those reported inside lecture rooms and the workshop area, where extensive activates of heavy machinery and use of petroleum products (such as lubricating oils). This implies that the health effects of exposure to tobacco smoking inside small micro-environmental places that are poorly ventilated can be very harmful. We also made a simple exposure and health risk assessment for the ingested dust (hand-to-mouth) by calculating the Estimated Daily Intake (EDI) and benzo(a)pyrene equivalent carcinogenic power (BaPE). The total EDI was less than 3.75ng/kg-bw/day whereas the BaPE was less than 385ng/g. These values are lower than what was reported in some previous studies in Europe and Asia.

  5. Occupational exposure to coal tar pitch volatiles, benzo/a/pyrene and dust in tyre production.

    Science.gov (United States)

    Rogaczewska, T; Ligocka, D

    1994-01-01

    Occupational exposure to coal tar pitch volatiles (CTPVs), benzo/a/pyrene (BaP) and dust was evaluated by means of individual measurements carried out in 80 workers and by stationary measurements on 16 work-posts in two divisions of the tyre producing plant. Dust and coal tar pitch volatiles concentrations in the air were determinated by the gravimetric method, measured, in the case of CPTVs, benzene-soluble fraction (BSF) with ultrasonic extraction. Benzo/a/pyrene analysis was performed using high performance liquid chromato-graphy (HPLC) with a spectrofluorimetric detector. It was found that nearly all personal sampling results for BaP were within the range 90%) which exceeded the admissible value (4 mg/m3) was found mainly only in the workers of the Semiproducts Division at some work-posts.

  6. A systematic review of occupational exposure to coal dust and the risk of interstitial lung diseases

    Science.gov (United States)

    Beer, Christiane; Kolstad, Henrik A.; Søndergaard, Klaus; Bendstrup, Elisabeth; Heederik, Dick; Olsen, Karen E.; Omland, Øyvind; Petsonk, Edward; Sigsgaard, Torben; Sherson, David L.; Schlünssen, Vivi

    2017-01-01

    ABSTRACT Objective: Exposure to coal dust can cause interstitial lung disease (ILD), but whether this is due to pure coal or to the contents of quartz in coal is less clear. Here, we systematically reviewed the relation between ‘pure coal’ and ILD. Methods: In a systematic review based on PRISMA criteria 2945 articles were identified. Strict eligibility criteria, which evaluated the ‘pure coal effect’, led to the inclusion of only nine studies. Results: Among these nine studies six studies indicated an independent effect of the non-quartz part of coal on the development and progression of ILD, two did not demonstrate an effect and one was inconclusive. Conclusions: Although an independent effect of non-quartz coal dust on the development of ILD is supported, due to methodological limitations the evidence is limited and further evidence is needed.

  7. Health effects from exposure to atmospheric mineral dust near Las Vegas, NV, USA

    Directory of Open Access Journals (Sweden)

    Deborah E. Keil

    2016-01-01

    Full Text Available Desert areas are usually characterized by a continuous deposition of fine airborne particles. Over time, this process results in the accumulation of silt and clay on desert surfaces. We evaluated health effects associated with regional atmospheric dust, or geogenic dust, deposited on surfaces in the Nellis Dunes Recreation Area (NDRA in Clark County, Nevada, a popular off-road vehicle (ORV recreational site frequented daily by riders, families, and day campers. Because of atmospheric mixing and the mostly regional origin of the accumulated particles, the re-suspended airborne dust is composed of a complex mixture of minerals and metals including aluminum, vanadium, chromium, manganese, iron, cobalt, copper, zinc, arsenic, strontium, cesium, lead, uranium, and others. Geogenic dust with a median diameter of 4.1 μm was administered via oropharyngeal aspiration to female B6C3F1 mice at doses of 0.01 to 100 mg dust/kg body weight, four times, a week apart, for 28-days. Immuno- and neurotoxicological outcomes 24 h following the last exposure were evaluated. Antigen-specific IgM responses were dose-responsively suppressed at 0.1, 1.0, 10 and 100 mg/kg/day. Splenic and thymic lymphocytic subpopulations and natural killer cell activity also were significantly reduced. Antibodies against MBP, NF-68, and GFAP were not affected, while brain CD3+ T cells were decreased in number. A lowest observed adverse effect level (LOAEL of 0.1 mg/kg/day and a no observed adverse effect level (NOAEL of 0.01 mg/kg/day were derived based on the antigen-specific IgM responses.

  8. Association of pediatric asthma severity with exposure to common household dust allergens

    Energy Technology Data Exchange (ETDEWEB)

    Gent, Janneane F., E-mail: janneane.gent@yale.edu [Yale Center for Perinatal, Pediatric and Environmental Epidemiology, Department of Epidemiology and Public Health, Yale University School of Medicine, One Church Street, 6th Floor, New Haven, CT 06510 (United States); Belanger, Kathleen [Yale Center for Perinatal, Pediatric and Environmental Epidemiology, Department of Epidemiology and Public Health, Yale University School of Medicine, One Church Street, 6th Floor, New Haven, CT 06510 (United States); Triche, Elizabeth W. [Brown University, Department of Community Health/Epidemiology, Providence, RI (United States); Bracken, Michael B. [Yale Center for Perinatal, Pediatric and Environmental Epidemiology, Department of Epidemiology and Public Health, Yale University School of Medicine, One Church Street, 6th Floor, New Haven, CT 06510 (United States); Beckett, William S. [Mount Auburn Hospital, Department of Internal Medicine, Cambridge, MA (United States); Leaderer, Brian P. [Yale Center for Perinatal, Pediatric and Environmental Epidemiology, Department of Epidemiology and Public Health, Yale University School of Medicine, One Church Street, 6th Floor, New Haven, CT 06510 (United States)

    2009-08-15

    Background: Reducing exposure to household dust inhalant allergens has been proposed as one strategy to reduce asthma. Objective: To examine the dose-response relationships and health impact of five common household dust allergens on disease severity, quantified using both symptom frequency and medication use, in atopic and non-atopic asthmatic children. Methods: Asthmatic children (N=300) aged 4-12 years were followed for 1 year. Household dust samples from two indoor locations were analyzed for allergens including dust mite (Der p 1, Der f 1), cat (Fel d 1), dog (Can f 1), cockroach (Bla g 1). Daily symptoms and medication use were collected in monthly telephone interviews. Annual disease severity was examined in models including allergens, specific IgE sensitivity and adjusted for age, gender, atopy, ethnicity, and mother's education. Results: Der p 1 house dust mite allergen concentration of 2.0 {mu}g/g or more from the main room and the child's bed was related to increased asthma severity independent of allergic status (respectively, OR 2.93, 95% CI 1.37, 6.30 for 2.0-10.0 {mu}g/g and OR 2.55 95% CI 1.13, 5.73 for {>=}10.0 {mu}g/g). Higher pet allergen levels were associated with greater asthma severity, but only for those sensitized (cat OR 2.41 95% CI 1.19, 4.89; dog OR 2.06 95% CI 1.01, 4.22). Conclusion: Higher levels of Der p 1 and pet allergens were associated with asthma severity, but Der p 1 remained an independent risk factor after accounting for pet allergens and regardless of Der p 1 specific IgE status.

  9. Genotoxic Evaluation of Mikania laevigata Extract on DNA Damage Caused by Acute Coal Dust Exposure

    Energy Technology Data Exchange (ETDEWEB)

    Freitas, T.P.; Heuser, V.D.; Tavares, P.; Leffa, D.D.; da Silva, G.A.; Citadini-Zanette, V.; Romao, P.R.T.; Pinho, R.A.; Streck, E.L.; Andrade,V.M. [University of Extremo Catarinense, Criciuma, SC (Brazil)

    2009-06-15

    We report data on the possible antigenotoxic activity of Mikania laevigata extract (MLE) after acute intratracheal instillation of coal dust using the comet assay in peripheral blood, bone marrow, and liver cells and the micronucleus test in peripheral blood of Wistar rats. The animals were pretreated for 2 weeks with saline solution (groups 1 and 2) or MLE (100 mg/kg) (groups 3 and 4). On day 15, the animals were anesthetized with ketamine (80 mg/kg) and xylazine (20 mg/kg), and gross mineral coal dust (3 mg/0.3 mL saline) (groups 2 and 4) or saline solution (0.3 mL) (groups 1 and 3) was administered directly in the lung by intratracheal administration. Fifteen days after coal dust or saline instillation, the animals were sacrificed, and the femur, liver, and peripheral blood were removed. The results showed a general increase in the DNA damage values at 8 hours for all treatment groups, probably related to surgical procedures that had stressed the animals. Also, liver cells from rats treated with coal dust, pretreated or not with MLE, showed statistically higher comet assay values compared to the control group at 14 days after exposure. These results could be expected because the liver metabolizes a variety of organic compounds to more polar by-products. On the other hand, the micronucleus assay results did not show significant differences among groups. Therefore, our data do not support the antimutagenic activity of M. laevigata as a modulator of DNA damage after acute coal dust instillation.

  10. Pharmaceutical dust exposure at pharmacies using automatic dispensing machines: a preliminary study.

    Science.gov (United States)

    Fent, Kenneth W; Durgam, Srinivas; Mueller, Charles

    2014-01-01

    Automatic dispensing machines (ADMs) used in pharmacies concentrate and dispense large volumes of pharmaceuticals, including uncoated tablets that can shed dust. We evaluated 43 employees' exposures to pharmaceutical dust at three pharmacies where ADMs were used. We used an optical particle counter to identify tasks that generated pharmaceutical dust. We collected 72 inhalable dust air samples in or near the employees' breathing zones. In addition to gravimetric analysis, our contract laboratory used internal methods involving liquid chromatography to analyze these samples for active pharmaceutical ingredients (APIs) and/or lactose, an inactive filler in tablets. We had to choose samples for these additional analyses because many methods used different extraction solvents. We selected 57 samples for analysis of lactose. We used real-time particle monitoring results, observations, and information from employees on the dustiness of pharmaceuticals to select 28 samples (including 13 samples that were analyzed for lactose) for analysis of specific APIs. Pharmaceutical dust was generated during a variety of tasks like emptying and refilling of ADM canisters. Using compressed air to clean canisters and manual count machines produced the overall highest peak number concentrations (19,000-580,000 particles/L) of smallest particles (count median aerodynamic diameter ≤ 2 μm). Employees who refilled, cleaned, or repaired ADM canisters, or hand filled prescriptions were exposed to higher median air concentrations of lactose (5.0-12 μg/m(3)) than employees who did other jobs (0.04-1.3 μg/m(3)), such as administrative/office work, labeling/packaging, and verifying prescriptions. We detected 10 APIs in air, including lisinopril, a drug prescribed for high blood pressure, levothyroxine, a drug prescribed for hypothyroidism, and methotrexate, a hazardous drug prescribed for cancer and other disorders. Three air concentrations of lisinopril (1.8-2.7 μg/m(3)) exceeded the lower

  11. Attempts to reduce exposure to fungi, β-glucan, bacteria, endotoxin and dust in vegetable greenhouses and a packaging unit.

    Science.gov (United States)

    Madsen, Anne Mette; Tendal, Kira; Frederiksen, Margit W

    2014-01-15

    Indoor handling of large amounts of plant materials occurs in different occupational settings including greenhouses and causes exposure to bioaerosols. The bioaerosol components fungi, β-glucan, bacteria and endotoxin are involved in different airway symptoms and health effects can be dose-dependent. Therefore, there is a persistent need to reduce exposure. The aims of this study were to identify tasks causing exposure and to evaluate preventive measures aimed at reducing exposure of greenhouse workers to bioaerosols, and to study factors affecting the exposure. We have focused on different exposure scenarios; one with high short-term exposure found during clearing of old cucumber plants; the other with long-term, mid-level exposure found during tomato picking, leaf nipping, stringing up tomato plants, and packaging of cucumbers. Clearing of non-dried cucumber plants compared with clearing of dried cucumber plants significantly reduced the exposure to dust, endotoxin, bacteria, fungal spores and β-glucan. More endotoxin and fungi are emitted and more of the emitted particles were of respirable size if the leaves were dried. Along the cucumber packaging line, exposure levels were highly specific to each personal subtask. The subtask 'unloading of cucumbers' was the source of exposure making task ventilation or shielding of the process a possibility. Elimination of leaf debris on the floor reduced the exposure to fungi significantly. However, leaf debris on the floor did not contribute significantly to the exposure to dust, endotoxin and bacteria. Furthermore, to eliminate leaf debris, it had to be cleared away and this was associated with a higher exposure to dust and endotoxin. The age of the plants affected the exposure level to bioaerosols with higher exposures from old plants. In conclusion, different tasks and subtasks cause very different exposure levels. It is possible to reduce exposure by identifying subtasks causing the exposure and by modifying work

  12. Geochemistry and health risk assessment of arsenic exposure to street dust in the zinc smelting district, Northeast China.

    Science.gov (United States)

    Xu, Sujuan; Zheng, Na; Liu, Jingshuang; Wang, Yang; Chang, Shouzhi

    2013-02-01

    The aim of this study was to investigate arsenic (As) accumulation in street dust and health risk of population. The investigation concentrated on: a. pollution levels of As in street dust; b. spatial distribution of As in street dust; c. physicochemical properties analysis of street dust; and d. assessment of population health risk due to As exposure to street dust. As concentration in street dust ranged from 3.33 to 185.1 mg kg(-1), with a mean of 33.10 mg kg(-1), which was higher than the background value of Liaoning soil. As contamination level of the area closing to Huludao Zinc Plant (HZP) was highest. Spatial variation showed that the pollution center was close to HZP, formed radial distribution pattern and extended to the northeast and southwest of HZP. The pH and organic matter of street dust were both higher than the background values of soil in Liaoning. There was significantly negative correlation between As concentration and the pH. The mass percentages of particles 180-100, 63, and 63 μm were 29.8, 3.7, 21.3, and 4.2 %, respectively. The highest of As concentration was found in the smallest particle size (63 μm). As loadings in the particles of grain size 180-100 and 63 μm were higher than other particle fractions. Results of the risk assessment indicated that the highest risk was associated with the ingestion of street dust particles. Health risk for different use scenarios to human decreased in the order of HZP > Industrial district > School > Commercial center > Residential area. Around HZP, Hazard Index (HI) for children and cancer risk of As by street dust exposure exceeded the acceptable values. It indicated that there was a potential adverse effect on children health by As exposure to the street dust of Huludao.

  13. Cats' Internal Exposure to Selected Brominated Flame Retardants and Organochlorines Correlated to House Dust and Cat Food.

    Science.gov (United States)

    Norrgran Engdahl, J; Bignert, A; Jones, B; Athanassiadis, I; Bergman, Å; Weiss, J M

    2017-03-07

    Pet cats may be used as a biomarker for assessing exposures to organohalogen compounds (OHCs) adsorbed to household dust in home environments. This study explores two exposure routes of OHCs, ingestion of OHCs (i) via house dust and (ii) via cat food. House dust from 17 Swedish homes and serum from the participating families' pet cats were collected, and cat food was purchased matching the diet reported. Paired samples of cat serum, house dust, and cat food were analyzed for brominated flame retardants/natural products (polybrominated diphenyl ethers (PBDEs), decabromobiphenyl (BB-209), decabromodiphenyl ethane (DBDPE), 2,4,6-tribromophenol (2,4,6-TBP), OH-PBDEs) and organochlorines (polychlorinated biphenyls (PCBs), 1,1-bis(4,4'-dichlorodiphenyl)-2,2,2-trichloroethane (4,4'-DDT), 1,1-bis(4,4'-dichlorodiphenyl)-2,2-dichloroethene (4,4'-DDE), hexachlorobenzene (HCB), pentachlorophenol (PCP)). Significant correlations were found between serum and dust samples from the living rooms for BDE-47 (p cat serum levels and household dust has been established, a finding that supports the hypothesis that dust is a significant exposure route for cats. Serum levels were also significantly correlated with concentrations found in cat food for 6-OH-BDE47 (p cats.

  14. World-Wide Indoor Exposure to Polyfluoroalkyl Phosphate Esters (PAPs) and other PFASs in Household Dust.

    Science.gov (United States)

    Eriksson, Ulrika; Kärrman, Anna

    2015-12-15

    Human exposure to perfluorooctanoic acid (PFOA) and other per- and polyfluoroalkyl substances (PFASs) is ongoing and in some cases increasing, despite efforts made to reduce emissions. The role of precursor compounds such as polyfluorinated phosphate esters (PAPs) has received increasing attention, but there are knowledge gaps regarding their occurrence and impact on human exposure. In this study, mono-, di-, and triPAPs, perfluorinated alkyl acids (PFAAs), saturated, and unsaturated fluorotelomer carboxylic acids (FTCA/FTUCAs), perfluoroalkane sulfonamides, and sulfonamidethanols (FOSA/FOSEs), and one fluorotelomer sulfonic acid (FTSA)) were compared in household dust samples from Canada, the Faroe Islands, Sweden, Greece, Spain, Nepal, Japan, and Australia. Mono-, di-, and triPAPs, including several diPAP homologues, were frequently detected in dust from all countries, revealing an ubiquitous spread in private households from diverse geographic areas, with significant differences between countries. The median levels of monoPAPs and diPAPs ranged from 3.7 ng/g to 1 023 ng/g and 3.6 ng/g to 692 ng/g, respectively, with the lowest levels found in Nepal and the highest in Japan. The levels of PAPs exceeded those of the other PFAS classes. These findings reveal the importance of PAPs as a source of PFAS exposure worldwide.

  15. Cancer risk assessment of human exposure to polycyclic aromatic hydrocarbons (PAHs) via indoor and outdoor dust based on probit model.

    Science.gov (United States)

    Kang, Yuan; Shao, Dingding; Li, Ning; Yang, Gelin; Zhang, Qiuyun; Zeng, Lixuan; Luo, Jiwen; Zhong, Wenfeng

    2015-03-01

    In the present study, the polycyclic aromatic hydrocarbons (PAHs) in indoor dust and outdoor dust including road and window dust around the traffic road in Hunan Province, China, were sampled and detected. The ∑PAHs in indoor dust ranged from 5007-24,236 ng g(-1), with a median of 14,049 ng g(-1). The ∑PAHs in road dust ranged from 3644-12,875 ng g(-1), with a median of 10,559 ng g(-1). The ∑PAHs in window dust ranged from 803-12,590 ng g(-1), with a median of 5459 ng g(-1). Similar pattern of PAHs was observed in road and window dust except in H3W and H4W samples, which was dominated by naphthalene (Nap), benzo(b+k)fluoranthene (B(b+k)F), phenanthrene (Phe), and fluorine (Fle). Indoor dust showed slightly different PAHs profiles, which was dominated by Nap, fluoranthene (Fla) and Phe. Risk assessment indicated that dermal contact and dust ingestion exposure pathways were more important than the inhalation pathway. Cancer risk of PAHs via dust varied from 2.73 × 10(-8)-8.04 × 10(-6), with a median of 2.06 × 10(-6) for children, and from 2 × 10(-8)-5.89 × 10(-6), with a median of 1.52 × 10(-6) for adult. Probit model showed that 76 and 71 % of samples in the sampling area would result in the risk of children and adult exposure to PAHs via dust higher than the acceptable level (1 × 10(-6)), respectively.

  16. Lifetime occupational exposure to dusts, gases and fumes is associated with bronchitis symptoms and higher diffusion capacity in COPD patients.

    NARCIS (Netherlands)

    Rodríguez, E.; Ferrer, J.; Zock, J.P.; Serra, I.; Antó, J.M.; Batlle, J. de; Kromhout, H.; Vermeulen, R.; Donaire-Gonzalez, D.; Benet, M.; Balcells, E.; Monso, E.; Gayete, A.; Garcia-Aymerich, J.

    2014-01-01

    Background: Occupational exposure to dusts, gases and fumes has been associated with reduced FEV1 and sputum production in COPD patients. The effect of occupational exposure on other characteristics of COPD, especially those reflecting emphysema, has not been studied in these patients. Methods: We s

  17. Lifetime occupational exposure to dusts, gases and fumes is associated with bronchitis symptoms and higher diffusion capacity in COPD patients

    NARCIS (Netherlands)

    Rodríguez, Esther; Ferrer, Jaume; Zock, Jan Paul; Serra, Ignasi; Antó, Josep M.; De Batlle, Jordi; Kromhout, Hans; Vermeulen, Roel; Donaire-González, David; Benet, Marta; Balcells, Eva; Monsó, Eduard; Gayete, Àngel; Garcia-Aymerich, Judith; Guerra, Stefano; Gea, Joaquim; Orozco-Levi, Mauricio; Vollmer, Ivan; Barberà, Joan Albert; Gómez, Federico P.; Paré, Carles; Roca, Josep; Rodriguez-Roisin, Robert; Agustí, Àlvar; Freixa, Xavier; Rodriguez, Diego A.; Gimeno, Elena; Portillo, Karina; Andreu, Jordi; Pallissa, Esther; Casan, Pere; Güell, Rosa; Giménez, Ana; Marín, Alicia; Morera, Josep; Farrero, Eva; Escarrabill, Joan; Ferrer, Antoni; Sauleda, Jaume; Togores, Bernat; Gáldiz, Juan Bautista; López, Lorena; Belda, José

    2014-01-01

    BACKGROUND: Occupational exposure to dusts, gases and fumes has been associated with reduced FEV1 and sputum production in COPD patients. The effect of occupational exposure on other characteristics of COPD, especially those reflecting emphysema, has not been studied in these patients.\

  18. Tetrabromobisphenol A and heavy metal exposure via dust ingestion in an e-waste recycling region in Southeast China.

    Science.gov (United States)

    Wu, Yuanyuan; Li, Yanyan; Kang, Duan; Wang, Jingjing; Zhang, Yanfang; Du, Dongli; Pan, Bishu; Lin, Zhenkun; Huang, Changjiang; Dong, Qiaoxiang

    2016-01-15

    This study was designed to investigate a prevalent brominated flame retardant tetrabromobisphenol A (TBBPA) and four heavy metals of Pb, Cr, As, Cd in dust samples (52 indoor and 52 outdoor) collected from residential houses in an e-waste recycling area in Southeast China. For TBBPA, the mean concentration in indoor dust (3435 ng/g, dw) was higher than that in outdoor dust (1998 ng/g, dw). For heavy metals, the mean concentrations of Pb, Cr, As, Cd were 399, 151, 48.13, and 5.85 mg/kg in indoor dust, respectively, and were 328, 191, 17.59, and 4.07 mg/kg in outdoor dust, respectively. Except for As, concentrations of TBBPA and other metals decreased with the increased distance away from the e-waste recycling center, suggesting significant contribution of e-waste activities. The daily exposure doses of TBBPA ranged from 0.04 to 7.50 ng/kg-bw/day for adults and from 0.31 to 58.54 ng/kg-bw/day for children, representing the highest values reported to date for TBBPA exposure via dust ingestion. Daily exposure doses of Cr, As, and Cd were all below the reference doses. However, daily exposure dose of Pb for children in areas near the e-waste processing center was above the reference dose, posing significant health concern for children in that region.

  19. Impact of an asbestos cement factory on mesothelioma incidence: global assessment of effects of occupational, familial, and environmental exposure.

    Science.gov (United States)

    Mensi, Carolina; Riboldi, Luciano; De Matteis, Sara; Bertazzi, Pier Alberto; Consonni, Dario

    2015-01-01

    Few studies have examined the incidence of malignant mesothelioma (MM) associated with distinct sources of asbestos exposure (occupational, familial, or environmental). We assessed the impact of asbestos exposure-global and by source-on the incidence of MM in Broni, an Italian town in which an asbestos cement factory once operated (1932-1993). Based on data collected by the Lombardy Mesothelioma Registry, we calculated the number of observed and expected MM cases among workers, their cohabitants, and people living in the area in 2000-2011. We identified 147 MM cases (17.45 expected), 138 pleural and nine peritoneal, attributable to exposure to asbestos from the factory. Thirty-eight cases had past occupational exposure at the factory (2.33 expected), numbering 32 men (26 pleural, six peritoneal) and six women (four pleural, two peritoneal). In the families of the workers, there were 37 MM cases (4.23 expected), numbering five men (all pleural) and 32 women (31 pleural, one peritoneal). Among residents in Broni or in the adjacent/surrounding towns, there were 72 cases of pleural MM (10.89 expected), numbering 23 men and 49 women. The largest MM excess was found in the towns of Broni (48 observed, 3.68 expected) and Stradella (16 observed, 1.85 expected). This study documents the large impact of the asbestos cement factory, with about 130 excess MM cases in a 12-year period. The largest MM burden was among women, from non-occupational exposure. Almost half of the MM cases were attributable to environmental exposure.

  20. Acute Respiratory Failure due to Alveolar Hemorrhage after Exposure to Organic Dust

    Directory of Open Access Journals (Sweden)

    Sun Mi Choi

    2016-05-01

    Full Text Available Diffuse alveolar hemorrhage (DAH is associated with severe outcomes. We report a case of acute respiratory failure that required mechanical ventilation and was clinically and pathologically diagnosed as DAH related to exposure to organic dust. A 39-year-old man, who had visited a warehouse to grade beans for purchase, was referred to our hospital for impending respiratory failure. His initial radiographic examinations revealed diffuse bilateral ground-glass opacities in his lungs and bronchoalveolar lavage resulted in progressively bloodier returns, which is characteristic of DAH. He underwent bedside open lung biopsy of his right lower lobe in the intensive care unit. Biopsy results revealed DAH and organization with accumulation of hemosiderin-laden macrophages and a few fibroblastic foci. The patient was treated with empirical antibiotics and high-dose corticosteroids and successfully weaned from mechanical ventilation. DAH might be considered in the differential diagnosis of patients with acute respiratory failure after exposure to organic particles.

  1. Respiratory Symptoms due to Occupational Exposure to Formaldehyde and MDF Dust in a MDF Furniture Factory in Eastern Thailand

    Science.gov (United States)

    Yingratanasuk, Tanongsak; Ekburanawat, Wiwat

    2016-01-01

    The study aimed to investigate factors associated with respiratory symptoms in workers in a medium-density fiberboard (MDF) furniture factory in Eastern Thailand. Data were collected from 439 employees exposed to formaldehyde and MDF dust using questionnaire and personal sampler (Institute of Occupational Medicine; IOM). The average concentration of formaldehyde from MDF dust was 2.62 ppm (SD 367), whereas the average concentration of MDF dust itself was 7.67 mg/m3 (SD 3.63). Atopic allergic history was a factor associated with respiratory irritation symptoms and allergic symptoms among the workers exposed to formaldehyde and were associated with respiratory irritation symptoms and allergic symptoms among those exposed to MDF dust. Exposure to MDF dust at high level (>5 mg/m3) was associated with respiratory irritation symptoms and allergic symptoms. Excluding allergic workers from the study population produced the same kind of results in the analysis as in all workers. The symptoms were associated with the high concentrations of formaldehyde and MDF dust in this factory. If the concentration of MDF dust was >5 mg/m3, the risk of irritation and allergic symptoms in the respiratory system increased. The respiratory health of the employees with atopic allergic history exposed to formaldehyde and MDF dust should be monitored closely. PMID:28119784

  2. Lung function reduction and chronic respiratory symptoms among workers in the cement industry: a follow up study

    Directory of Open Access Journals (Sweden)

    Zeleke Zeyede K

    2011-11-01

    Full Text Available Abstract Background There are only a few follow-up studies of respiratory function among cement workers. The main aims of this study were to measure total dust exposure, to examine chronic respiratory symptoms and changes in lung function among cement factory workers and controls that were followed for one year. Methods The study was conducted in two cement factories in Ethiopia. Totally, 262 personal measurements of total dust among 105 randomly selected workers were performed. Samples of total dust were collected on 37-mm cellulose acetate filters placed in closed faced Millipore-cassettes. Totally 127 workers; 56 cleaners, 44 cement production workers and 27 controls were randomly selected from two factories and examined for lung function and interviewed for chronic respiratory symptoms in 2009. Of these, 91 workers; 38 cement cleaners (mean age 32 years, 33 cement production workers (36 years and 20 controls (38 years were examined with the same measurements in 2010. Results Total geometric mean dust exposure among cleaners was 432 mg/m3. The fraction of samples exceeding the Threshold Limit Value (TLV of 10 mg/m3 for the cleaners varied from 84-97% in the four departments. The levels were considerably lower among the production workers (GM = 8.2 mg/m3, but still 48% exceeded 10 mg/m3. The prevalence of all the chronic respiratory symptoms among both cleaners and production workers was significantly higher than among the controls. Forced Expiratory Volume in one second (FEV1 and FEV1/Forced Vital Capacity (FEV1/FVC were significantly reduced from 2009 to 2010 among the cleaners (p Conclusions The high prevalence of chronic respiratory symptoms and reduction in lung function is probably associated with high cement dust exposure. Preventive measures are needed to reduce the dust exposure.

  3. Respirable dust and silica exposure among World Trade Center cleanup workers.

    Science.gov (United States)

    Pavilonis, Brian T; Mirer, Franklin E

    2017-03-01

    The cleanup effort following the destruction of the World Trade Center (WTC) was unprecedented and involved removal of 1.8 million tons of rubble over a nine-month period. Work at the site occurred 24 hr a day, 7 days a week and involved thousands of workers during the process. The Occupational Safety and Health Administration (OSHA) conducted personal and area exposure sampling during the cleanup of the site. Secondary data analysis was performed on OSHA air sampling data for respirable dust and silica from September 2001 to June 2002 at the WTC recovery site to characterize workers' exposure. Results for silica and respirable particulate were stratified by area and personal samples as well as job task for analysis. Of 1108 samples included in the analysis, 693 were personal and 415 were area. The mean result for personal silica samples was 42 μg/m(3) (Range: 4.2-1800 μg/m(3)). Workers identified as drillers had the highest mean silica exposure (72 μg/m(3); range: 5.8-800 μg/m(3)) followed by workers identified as dock builders (67 μg/m(3); range: 5.8-670 μg/m(3)). The mean result for personal samples for respirable particulate was 0.44 mg/m(3) (range: 0.00010-13 mg/m(3)). There were no discernable trends in personal respirable dust and silica concentrations with date.

  4. Evaluation of the Webler-Brown model for estimating tetrachloroethylene exposure from vinyl-lined asbestos-cement pipes

    Directory of Open Access Journals (Sweden)

    Heeren Timothy C

    2008-06-01

    Full Text Available Abstract Background From May 1968 through March 1980, vinyl-lined asbestos-cement (VL/AC water distribution pipes were installed in New England to avoid taste and odor problems associated with asbestos-cement pipes. The vinyl resin was applied to the inner pipe surface in a solution of tetrachloroethylene (perchloroethylene, PCE. Substantial amounts of PCE remained in the liner and subsequently leached into public drinking water supplies. Methods Once aware of the leaching problem and prior to remediation (April-November 1980, Massachusetts regulators collected drinking water samples from VL/AC pipes to determine the extent and severity of the PCE contamination. This study compares newly obtained historical records of PCE concentrations in water samples (n = 88 with concentrations estimated using an exposure model employed in epidemiologic studies on the cancer risk associated with PCE-contaminated drinking water. The exposure model was developed by Webler and Brown to estimate the mass of PCE delivered to subjects' residences. Results The mean and median measured PCE concentrations in the water samples were 66 and 0.5 μg/L, respectively, and the range extended from non-detectable to 2432 μg/L. The model-generated concentration estimates and water sample concentrations were moderately correlated (Spearman rank correlation coefficient = 0.48, p Conclusion PCE concentration estimates generated using the Webler-Brown model were moderately correlated with measured water concentrations. The present analysis suggests that the exposure assessment process used in prior epidemiological studies could be improved with more accurate characterization of water flow. This study illustrates one method of validating an exposure model in an epidemiological study when historical measurements are not available.

  5. Ceiling (attic) dust: a "museum" of contamination and potential hazard.

    Science.gov (United States)

    Davis, Jeffrey J; Gulson, Brian L

    2005-10-01

    Ceiling or attic dusts provide an indirect measure of air pollution integrated over varying time periods. We undertook an investigation into the particle-size distributions and sources and exposure pathways of metals in ceiling dusts from 38 houses in the city of Sydney, Australia. The houses ranged in age from 4 to 106 years and were grouped into three settings: industrial, semi-industrial, and non-industrial. The main roof types were terracotta tile (n=23), cement tile (n=8), and corrugated iron (n=4), with two slate and one asbestos. Soils and rocks from the Sydney area were also analyzed to provide "background" values and allow the estimation of enrichment factors. The bulk of the dusts contained particles derived from soil of crustal origin and organic plant material, with an anthropogenic component estimated at up to 25%. Particle sizes from selected dust samples showed a bimodal distribution, and the volumes of fine dusts were 50% terracotta tile, cement, and iron, median regression analyses showed that there were no significant effects with respect to age. Median regression analyses for terracotta tile, cement tile, and corrugated iron roofs showed a "roof" effect for Cu and V. Significant correlations (P0.03) were observed between most of the metals As-Cd-Cu-Pb-Sb-Zn, especially from the industrial settings. Pathways of dust exposure in this study are classified as being passive or active based upon the probable route of dust infiltration. Ceiling dusts pose a probable health hazard if the dust is disturbed and allowed to plume within the living areas of a dwelling, thereby exposing the occupants, especially children, to elevated levels of metals and fine particulates. Modeling shows that exposure to the elevated levels of Pb in dust could give rise to blood lead concentrations exceeding current guidelines for the industrial and semi-industrial areas.

  6. Cotton Dust Exposure and Respiratory Disorders among Textile Workers at a Textile Company in the Southern Part of Benin

    Science.gov (United States)

    Hinson, Antoine Vikkey; Lokossou, Virgil K.; Schlünssen, Vivi; Agodokpessi, Gildas; Sigsgaard, Torben; Fayomi, Benjamin

    2016-01-01

    The textile industry sector occupies a prominent place in the economy of Benin. It exposes workers to several occupational risks, including exposure to cotton dust. To assess the effect of exposure to cotton dust on the health of workers, this study was initiated and conducted in a Beninese cotton industry company. The objective of the study was to evaluate the respiratory disorders among the textile workers exposed to cotton dust and the cross-sectional study involved 656 subjects exposed to cotton dust and 113 non-exposed subjects. The methods used are mainly based on a survey using a questionnaire of organic dust designed by the International Commission of Occupational Health (ICOH); and on the measures of lung function parameters (FEV1 and FVC). The main results of the different analyzes revealed that subjects exposed to cotton dust have more respiratory symptoms than unexposed subjects (36.9% vs. 21.2%). The prevalence of chronic cough, expectorations, dyspnoea, asthma and chronic bronchitis are 16.8%, 9.8%, 17.3%, 2.6%, and 5.9% respectively among the exposed versus 2.6%, 0.8%, 16.8%, 0% and 0.8% among the unexposed subjects. The prevalence of byssinosis is 44.01%.The prevalence of symptoms is dependent on the sector of activity and the age of the subject. These results should encourage medical interventions and technical prevention especially since the textile industry occupies an important place in the Benin’s economy. PMID:27618081

  7. Cotton Dust Exposure and Respiratory Disorders among Textile Workers at a Textile Company in the Southern Part of Benin.

    Science.gov (United States)

    Hinson, Antoine Vikkey; Lokossou, Virgil K; Schlünssen, Vivi; Agodokpessi, Gildas; Sigsgaard, Torben; Fayomi, Benjamin

    2016-01-01

    The textile industry sector occupies a prominent place in the economy of Benin. It exposes workers to several occupational risks, including exposure to cotton dust. To assess the effect of exposure to cotton dust on the health of workers, this study was initiated and conducted in a Beninese cotton industry company. The objective of the study was to evaluate the respiratory disorders among the textile workers exposed to cotton dust and the cross-sectional study involved 656 subjects exposed to cotton dust and 113 non-exposed subjects. The methods used are mainly based on a survey using a questionnaire of organic dust designed by the International Commission of Occupational Health (ICOH); and on the measures of lung function parameters (FEV₁ and FVC). The main results of the different analyzes revealed that subjects exposed to cotton dust have more respiratory symptoms than unexposed subjects (36.9% vs. 21.2%). The prevalence of chronic cough, expectorations, dyspnoea, asthma and chronic bronchitis are 16.8%, 9.8%, 17.3%, 2.6%, and 5.9% respectively among the exposed versus 2.6%, 0.8%, 16.8%, 0% and 0.8% among the unexposed subjects. The prevalence of byssinosis is 44.01%.The prevalence of symptoms is dependent on the sector of activity and the age of the subject. These results should encourage medical interventions and technical prevention especially since the textile industry occupies an important place in the Benin's economy.

  8. Traffic signatures in suspended dust at pedestrian levels in semiarid zones: Implications for human exposure

    Science.gov (United States)

    Meza-Figueroa, Diana; González-Grijalva, Belem; Del Río-Salas, Rafael; Coimbra, Rute; Ochoa-Landin, Lucas; Moreno-Rodríguez, Verónica

    2016-08-01

    Deeper knowledge on dust suspension processes along semiarid zones is critical for understanding potential impacts on human health. Hermosillo city, located in the heart of the Sonoran Desert was chosen to evaluate such impacts. A one-year survey of Total Suspended Particulate Matter (TSPM) was conducted at two different heights (pedestrian and rooftop level). The minimum values of TSPM were reported during monsoon season and winter. Maximum values showed a bimodal distribution, with major peaks associated with increase and decrease of temperature, as well as decreasing humidity. Concentrations of TSPM were significantly exceeded at pedestrian level (∼44% of analyzed days) when compared to roof level (∼18% of analyzed days). Metal concentrations of As, Pb, Cu, Sb, Be, Mg, Ni, and Co were higher at pedestrian level than at roof level. Pixel counting and interpretations based on scanning electron microscopy of dust filters showed a higher percentage of fine particulate fractions at pedestrian level. These fractions occur mainly as metal-enriched agglomerates resembling coarser particles. According to worldwide guidelines, particulate matter sampling should be conducted by monitoring particle sizes equal and inferior to PM10. However, this work suggests that such procedures may compromise risk assessment in semiarid environments, where coarse particles act as main carriers for emergent contaminants related to traffic. This effect is especially concerning at pedestrian level, leading to an underestimation of potential impacts of human exposure. This study brings forward novel aspects that are of relevance for those concerned with dust suspension processes across semiarid regions and related impact on human health.

  9. Household mold and dust allergens: Exposure, sensitization and childhood asthma morbidity

    Energy Technology Data Exchange (ETDEWEB)

    Gent, Janneane F., E-mail: janneane.gent@yale.edu [Yale Center for Perinatal, Pediatric and Environmental Epidemiology, Department of Epidemiology and Public Health, Yale University School of Medicine, One Church Street, 6th Floor, New Haven, CT 06510 (United States); Kezik, Julie M., E-mail: julie.colburn@yale.edu [Yale Center for Perinatal, Pediatric and Environmental Epidemiology, Department of Epidemiology and Public Health, Yale University School of Medicine, One Church Street, 6th Floor, New Haven, CT 06510 (United States); Hill, Melissa E., E-mail: melissa.hill@yale.edu [Yale Center for Perinatal, Pediatric and Environmental Epidemiology, Department of Epidemiology and Public Health, Yale University School of Medicine, One Church Street, 6th Floor, New Haven, CT 06510 (United States); Tsai, Eling, E-mail: tsai.umiami@gmail.com [Yale Center for Perinatal, Pediatric and Environmental Epidemiology, Department of Epidemiology and Public Health, Yale University School of Medicine, One Church Street, 6th Floor, New Haven, CT 06510 (United States); Li, De-Wei, E-mail: DeWei.Li@ct.gov [Connecticut Agricultural Experiment Station, Valley Laboratory, 153 Cook Hill Road, Windsor, CT 06095 (United States); Leaderer, Brian P., E-mail: brian.leaderer@yale.edu [Yale Center for Perinatal, Pediatric and Environmental Epidemiology, Department of Epidemiology and Public Health, Yale University School of Medicine, One Church Street, 6th Floor, New Haven, CT 06510 (United States)

    2012-10-15

    Background: Few studies address concurrent exposures to common household allergens, specific allergen sensitization and childhood asthma morbidity. Objective: To identify levels of allergen exposures that trigger asthma exacerbations in sensitized individuals. Methods: We sampled homes for common indoor allergens (fungi, dust mites (Der p 1, Der f 1), cat (Fel d 1), dog (Can f 1) and cockroach (Bla g 1)) for levels associated with respiratory responses among school-aged children with asthma (N=1233) in a month-long study. Blood samples for allergy testing and samples of airborne fungi and settled dust were collected at enrollment. Symptoms and medication use were recorded on calendars. Combined effects of specific allergen sensitization and level of exposure on wheeze, persistent cough, rescue medication use and a 5-level asthma severity score were examined using ordered logistic regression. Results: Children sensitized and exposed to any Penicillium experienced increased risk of wheeze (odds ratio [OR] 2.12 95% confidence interval [CI] 1.12, 4.04), persistent cough (OR 2.01 95% CI 1.05, 3.85) and higher asthma severity score (OR 1.99 95% CI 1.06, 3.72) compared to those not sensitized or sensitized but unexposed. Children sensitized and exposed to pet allergen were at significantly increased risk of wheeze (by 39% and 53% for Fel d 1>0.12 {mu}g/g and Can f 1>1.2 {mu}g/g, respectively). Increased rescue medication use was significantly associated with sensitization and exposure to Der p 1>0.10 {mu}g/g (by 47%) and Fel d 1>0.12 {mu}g/g (by 32%). Conclusion: Asthmatic children sensitized and exposed to low levels of common household allergens Penicillium, Der p 1, Fel d 1 and Can f 1 are at significant risk for increased morbidity. - Highlights: Black-Right-Pointing-Pointer Few studies address concurrent allergen exposures, sensitization and asthma morbidity. Black-Right-Pointing-Pointer Children with asthma were tested for sensitivity to common indoor allergens

  10. Effect of jute dust exposure on ventilatory function and the pertinence of cough and smoking to the response.

    Science.gov (United States)

    Chattopadhyay, B P; Alams, J; Gangopadhyay, P K; Saiyed, H N

    1995-06-01

    The ventilatory capacity of 32 men exposed to jute dust in the jute industry, was estimated at the beginning and end of shifts on the first day and last day of a working week. A detailed occupational, clinical and smoking history was recorded and a more detailed questionnaire on respiratory symptoms was completed prior to the pulmonary function tests. The presence of a productive cough among workers was noted. A mean decrease of forced expiratory volume at one second (FEV1) was observed among workers according to processes, concentration of dust exposure and smoking habit on the first day and last day of the week. The mean difference of values was observed in most of the comparisons but only a few were statistically significant. Low mean values of FEV1 were observed in workers having high dust exposure, a smoking history and productive cough in comparison to the low dust exposure group, non-smokers and workers without cough symptoms. The significant deterioration of FEV1 was found between before shift and after shift values of the low dust exposed group of workers who had a cough and smoking history. The relevance of these factors on the ventilatory function is observed and discussed.

  11. Estimation of individual dust exposure by magnetopneumography in stainless steel production.

    Science.gov (United States)

    Huvinen, M; Oksanen, L; Kalliomäki, K; Kalliomäki, P L; Moilanen, M

    1997-06-20

    The objectives of the study were to measure the magnetic dust lung burden of workers in stainless steel production by magnetopneumography (MPG) and to investigate the relationship of the results with air-borne concentrations of dust, total and hexavalent chromium as well as urinary excretion of chromium. There were 128 workers from the chromite mine, sintering plant, ferrochrome smelter, stainless steel smelting shop, cold rolling mill and welding shop in the exposed groups and five persons from the office staff in the control group. The remanent magnetic field (RMF) in the lungs was slightly elevated among workers in the ferrochromium and steel smelting shops; the levels were, however, lower than those reported for welders earlier and those observed in the welding/repair shop. Workers in the mine, concentrator and sintering plants and in the cold rolling mill exhibited remanent magnetic fields comparable to the referents. There was a relationship between the RMF and the actual urinary chromium concentration. Miners and concentrator and sintering plant workers showed retarded relaxation rate (ReR) of the remanent magnetic field. However, the RMF of the first two of these groups were low (< 0.1 nT) and this made it difficult to measure the ReR accurately. The duration of exposure correlated weakly but significantly with the relaxation rate, while smoking was not related to it.

  12. Human Arsenic exposure via dust across the different ecological zones of Pakistan.

    Science.gov (United States)

    Alamdar, Ambreen; Eqani, Syed Ali Musstjab Akber Shah; Ali, Saeed Waqar; Sohail, Mohammad; Bhowmik, Avit Kumar; Cincinelli, Alessandra; Subhani, Marghoob; Ghaffar, Bushra; Ullah, Rizwan; Huang, Qingyu; Shen, Heqing

    2016-04-01

    The present study aims to assess the arsenic (As) levels into dust samples and its implications for human health, of four ecological zones of Pakistan, which included northern frozen mountains (FMZ), lower Himalyian wet mountains (WMZ), alluvial riverine plains (ARZ), and low lying agricultural areas (LLZ). Human nail samples (N=180) of general population were also collected from the similar areas and all the samples were analysed by using ICP-MS. In general the higher levels (pPakistan. Risk estimation reflected higher hazard index (HI) values of non-carcinogenic risk (HI>1) for children populations in all areas (except FMZ), and for adults in LLZ (0.74) and ARZ (0.55), suggesting that caution should be paid about the dust exposure. Similarly, carcinogenic risk assessment also highlighted potential threats to the residents of LLZ and ARZ, as in few cases (5-10%) the values exceeded the range of US-EPA threshold limits (10(-6)-10(-4)).

  13. Wood dust exposure during furniture manufacture--results from an Australian survey and considerations for threshold limit value development.

    Science.gov (United States)

    Pisaniello, D L; Connell, K E; Muriale, L

    1991-11-01

    A survey of time-weighted average (TWA) personal inhalable dust exposures for woodworkers in 15 Australian furniture factories was undertaken. There was significant variation in the individual dust measurements with mean exposures of 3.2, 5.2, and 3.5 mg/m3 for wood machinists, cabinetmakers, and chair framemakers, respectively. Hardwoods, softwoods, and reconstituted woods are used in the industry, but only minor differences in mean exposures or particle size distributions were found for the broad categories. In addition, a modified British Medical Research Council respiratory questionnaire was used to obtain information about work-related symptoms and job activities. Compared with a control group, the woodworkers reported more eye, ear, and nasal problems, with the differences being statistically significant. However, among the woodworkers themselves, with the exception of several nasal symptoms, the prevalences of reported symptoms were poorly correlated with gravimetric measurements of personal dust exposure. The problem of selection bias in cross-sectional studies is discussed. For a mean TWA personal exposure of about 3 mg/m3, hardwood users were more likely to report nasal symptoms than users of reconstituted wood. The question of appropriate exposure standards for woods in general is addressed by reference to those important health effects, besides sino-nasal cancer, that have been investigated. Further exposure guidelines should be formulated for groups of woods that are known to cause a common health effect, such as nasal/respiratory sensitization.

  14. Effects of Fetal Exposure to Asian Sand Dust on Development and Reproduction in Male Offspring.

    Science.gov (United States)

    Yoshida, Seiichi; Ichinose, Takamichi; Arashidani, Keiichi; He, Miao; Takano, Hirohisa; Shibamoto, Takayuki

    2016-11-23

    In recent experimental studies, we reported the aggravating effects of Asian sand dust (ASD) on male reproduction in mice. However, the effects of fetal ASD exposure on male reproduction have not been investigated. The present study investigated the effects of fetal ASD exposure on reproduction in male offspring. Using pregnant CD-1 mice, ASD was administered intratracheally on days 7 and 14 of gestation, and the reproduction of male offspring was determined at 5, 10, and 15 weeks after birth. The secondary sex ratio was significantly lower in the fetal ASD-exposed mice than in the controls. Histologic examination showed partial vacuolation of seminiferous tubules in immature mice. Moreover, daily sperm production (DSP) was significantly less in the fetal ASD-exposed mice than in the controls. DSP in the fetal ASD-exposed mice was approximately 10% less than the controls at both 5 and 10 weeks. However, both the histologic changes and the DSP decrease were reversed as the mice matured. These findings suggest that ASD exposure affects both the fetal development and the reproduction of male offspring. In the future, it will be necessary to clarify the onset mechanisms of ASD-induced male fetus death and male reproductive disorders.

  15. K-ras mutations in sinonasal cancers in relation to wood dust exposure

    DEFF Research Database (Denmark)

    Bornholdt, Jette; Hansen, Johnni; Steiniche, Torben

    2008-01-01

    carefully reviewed pathologically before inclusion. Paraffin embedded tumour samples from 58 adenocarcinomas, 109 squamous cell carcinomas and 7 other carcinomas were analysed for K-ras codon 12, 13 and 61 point mutations by restriction fragment length polymorphisms and direct sequencing. Information...... mutations were suggested to be related to wood dust exposure, but these studies were too limited to detect statistically significant associations. Methods We examined 174 cases of sinonasal cancer diagnosed in Denmark in the period from 1991 to 2001. To ensure uniformity, all histological diagnoses were...... to unexposed [OR = 21.0, CI = 8.0–55.0]. K-ras was mutated in 13% of the adenocarcinomas (seven patients) and in 1% of squamous cell carcinomas (one patient). Of these eight mutations, five mutations were located in the codon 12. The exact sequence change of remaining three could not be identified...

  16. A Comparison of "Total Dust" and Inhalable Personal Sampling for Beryllium Exposure

    Energy Technology Data Exchange (ETDEWEB)

    Carter, Colleen M. [Tulane Univ., New Orleans, LA (United States). School of Public Health and Tropical Medicine

    2012-05-09

    In 2009, the American Conference of Governmental Industrial Hygienists (ACGIH) reduced the Beryllium (Be) 8-hr Time Weighted Average Threshold Limit Value (TLV-TWA) from 2.0 μg/m3 to 0.05 μg/m3 with an inhalable 'I' designation in accordance with ACGIH's particle size-selective criterion for inhalable mass. Currently, per the Department of Energy (DOE) requirements, the Lawrence Livermore National Laboratory (LLNL) is following the Occupational Health and Safety Administration (OSHA) Permissible Exposure Limit (PEL) of 2.0 μg/m3 as an 8-hr TWA, which is also the 2005 ACGIH TLV-TWA, and an Action Level (AL) of 0.2 μg/m3 and sampling is performed using the 37mm (total dust) sampling method. Since DOE is considering adopting the newer 2009 TLV guidelines, the goal of this study was to determine if the current method of sampling using the 37mm (total dust) sampler would produce results that are comparable to what would be measured using the IOM (inhalable) sampler specific to the application of high energy explosive work at LLNL's remote experimental test facility at Site 300. Side-by-side personal sampling using the two samplers was performed over an approximately two-week period during chamber re-entry and cleanup procedures following detonation of an explosive assembly containing Beryllium (Be). The average ratio of personal sampling results for the IOM (inhalable) vs. 37-mm (total dust) sampler was 1.1:1 with a P-value of 0.62, indicating that there was no statistically significant difference in the performance of the two samplers. Therefore, for the type of activity monitored during this study, the 37-mm sampling cassette would be considered a suitable alternative to the IOM sampler for collecting inhalable particulate matter, which is important given the many practical and economic advantages that it presents. However, similar comparison studies would be necessary for this conclusion to be

  17. Exposure to rubber process dust and fume since 1970s in the United Kingdom; influence of origin of measurement data.

    NARCIS (Netherlands)

    Agostini, M.; de Vocht, F.; van Tongeren, M.; Cherrie, J.W.; Galea, K.S.; Kromhout, H.

    2010-01-01

    The objective of this study was to compare measured concentrations of rubber process dust and rubber fume originating from different sources in the British rubber manufacturing industry. Almost 8000 exposure measurements were obtained from industry-based survey results collected by the British Rubbe

  18. Quartz and respirable dust in the Dutch construction industry: a baseline exposure assessment as part of a multidimensional intervention approach.

    Science.gov (United States)

    van Deurssen, Erik; Pronk, Anjoeka; Spaan, Suzanne; Goede, Henk; Tielemans, Erik; Heederik, Dick; Meijster, Tim

    2014-07-01

    Quartz exposure can cause several respiratory health effects. Although quartz exposure has been described in several observational workplace studies, well-designed intervention studies that investigate the effect of control strategies are lacking. This article describes a baseline exposure study that is part of a multidimensional intervention program aiming to reduce quartz exposure among construction workers. In this study, personal respirable dust and quartz exposure was assessed among 116 construction workers (bricklayers, carpenters, concrete drillers, demolishers, and tuck pointers). Possible determinants of exposure, like job, tasks, and work practices, use of control measures, and organizational and psychosocial factors, were explored using exposure models for respirable dust and quartz separately. Stratified analyses by job title were performed to evaluate the effect of control measures on exposure and to explore the association between control measures and psychosocial factors. Overall, 62% of all measurements exceeded the Dutch occupational exposure limit for quartz and 11% for respirable dust. Concrete drillers and tuck pointers had the highest exposures for quartz and respirable dust (0.20 and 3.43mg m(-3), respectively). Significant predictors of elevated quartz exposure were abrasive tasks and type of material worked on. Surprisingly, in a univariate model, an increased knowledge level was associated with an increase in exposure. Although control measures were used infrequently, if used they resulted in approximately 40% reduction in quartz exposure among concrete drillers and tuck pointers. Only among concrete drillers, the use of control measures was associated with a higher score for social influence (factor 1.6); knowledge showed an inverse association with use of control measures for concrete drillers, demolishers, and tuck pointers. In conclusion, the detailed information on determinants of exposure, use of control measures, and constraints to

  19. Inhaled dust and disease

    Energy Technology Data Exchange (ETDEWEB)

    Holt, P.F.

    1987-01-01

    This book discusses the following: the respiratory system; respirable dust; the fate of inhaled dust; translocation and some general effects of inhaled dust; silicosis; experimental research on silica-related disease; natural fibrous silicates; asbestos dust levels and dust sources; asbestos-related diseases - asbestosis, lung cancer, mesothelioma and other diseases, cancers at sites other than lung and pleura; experimental research relating to asbestos-related diseases; asbestos hazard - mineral types and hazardous occupations, neighbourhood and domestic hazard; silicates other than asbestos-man-made mineral fibres, mineral silicates and cement; metals; coal mine dust, industrial carbon and arsenic; natural and synthetic organic substances; dusts that provoke allergic alveolitis; tobacco smoke.

  20. Effect of reduced exposure times on the cytotoxicity of resin luting cements cured by high-power led

    Directory of Open Access Journals (Sweden)

    Gulfem Ergun

    2011-06-01

    Full Text Available OBJECTIVE: Applications of resin luting agents and high-power light-emitting diodes (LED light-curing units (LCUs have increased considerably over the last few years. However, it is not clear whether the effect of reduced exposure time on cytotoxicity of such products have adequate biocompatibility to meet clinical success. This study aimed at assessing the effect of reduced curing time of five resin luting cements (RLCs polymerized by high-power LED curing unit on the viability of a cell of L-929 fibroblast cells. MATERIAL AND METHODS: Disc-shaped samples were prepared in polytetrafluoroethylene moulds with cylindrical cavities. The samples were irradiated from the top through the ceramic discs and acetate strips using LED LCU for 20 s (50% of the manufacturer's recommended exposure time and 40 s (100% exposure time. After curing, the samples were transferred into a culture medium for 24 h. The eluates were obtained and pipetted onto L-929 fibroblast cultures (3x10(4 per well and incubated for evaluating after 24 h. Measurements were performed by dimethylthiazol diphenyltetrazolium assay. Statistical significance was determined by two-way ANOVA and two independent samples were compared by t-test. RESULTS: Results showed that eluates of most of the materials polymerized for 20 s (except Rely X Unicem and Illusion reduced to a higher extent cell viability compared to samples of the same materials polymerized for 40 s. Illusion exhibited the least cytotoxicity for 20 s exposure time compared to the control (culture without samples followed by Rely X Unicem and Rely X ARC (90.81%, 88.90%, and 83.11%, respectively. For Rely X ARC, Duolink and Lute-It 40 s exposure time was better (t=-1.262 p=0,276; t=-9.399 p=0.001; and t=-20.418 p<0.001, respectively. CONCLUSION: The results of this study suggest that reduction of curing time significantly enhances the cytotoxicity of the studied resin cement materials, therefore compromising their clinical

  1. Checklist Model to Improve Work Practices in Small-Scale Demolition Operations with Silica Dust Exposures

    Directory of Open Access Journals (Sweden)

    Paul Succop

    2012-01-01

    Full Text Available A systematic approach was developed to review, revise and adapt existing exposure control guidance used in developed countries for use in developing countries. One-page employee and multiple-page supervisor guidance sheets were adapted from existing documents using a logic framework and workers were trained to use the information to improve work practices. Interactive, hands-on training was delivered to 26 workers at five small-scale demolition projects in Maputo City, Mozambique, and evaluated. A pre-and-post walkthrough survey used by trained observers documented work practice changes. Worker feedback indicated that the training was effective and useful. Workers acquired knowledge (84% increase, p < 0.01 and applied the work practice guidance. The difference of proportions between use of work practice components before and after the intervention was statistically significant (p < 0.05. Changes in work practices following training included preplanning, use of wet methods and natural ventilation and end-of-task review. Respirable dust measurements indicated a reduction in exposure following training. Consistency in observer ratings and observations support the reliability and validity of the instruments. This approach demonstrated the short-term benefit of training in changing work practices; follow-up is required to determine the long-term impact on changes in work practices, and to evaluate the need for refresher training.

  2. Investigating relationships between biomarkers of exposure and environmental copper and manganese levels in house dusts from a Portuguese industrial city.

    Science.gov (United States)

    Reis, A P; Costa, S; Santos, I; Patinha, C; Noack, Y; Wragg, J; Cave, M; Sousa, A J

    2015-08-01

    This study reports on data obtained from a pilot survey focusing on house dust and toenail metal(loids) concentrations in residents living in the industrial city of Estarreja. The study design hereby described aims at investigating relationships between human toenails and both copper and manganese levels in settled house dusts. A total of 21 households and 30 individuals were recruited for the pilot study: 19 households corresponding to 27 residents living near the industrial complex, forming the exposed group, plus 2 households and 3 residents from residential areas with no anticipated environmental contaminants that were used for comparison. Factorial analysis was used for source identification purposes. Investigation on the potential influence of environmental factors over copper and manganese levels in the toenails was carried out via questionnaire data and multiple correspondence analysis. The results show that copper concentrations are more elevated in the indoor dusts, while manganese concentrations are more elevated in the outdoor dust samples. The geometrical relationships in the datasets suggest that the backyard soil is a probable source of manganese to the indoor dust. Copper and manganese contents in the toenail clippings are more elevated in children than in adults, but the difference between the two age groups is not statistically significant (p > 0.05). Investigation of environmental factors influencing the exposure-biomarker association indicates a probable relationship between manganese contents in indoor dust and manganese levels in toenail clippings, a result that is partially supported by the bioaccessibility estimates. However, for copper, no relationship was found between indoor dusts and the biomarkers of exposure.

  3. Effect of Wood Dust on Respiratory Health Status of Carpenters

    OpenAIRE

    Mohan, Mamta; Aprajita; Panwar, Neeraj Kant

    2013-01-01

    Introduction: Occupational lung diseases form an important part of clinical medicine. Exposure to various chemicals or toxins which are manufactured or processed in industries are lethal for the workers in industries. Although these chemicals at workplace are known to invariably affect all body systems, lungs are most vulnerable to airborne hazards which are caused due to exposure to wood dust in welding, cement and wood industrial sectors.

  4. Lifetime occupational exposure to dusts, gases and fumes is associated with bronchitis symptoms and higher diffusion capacity in COPD patients.

    Directory of Open Access Journals (Sweden)

    Esther Rodríguez

    Full Text Available BACKGROUND: Occupational exposure to dusts, gases and fumes has been associated with reduced FEV1 and sputum production in COPD patients. The effect of occupational exposure on other characteristics of COPD, especially those reflecting emphysema, has not been studied in these patients. METHODS: We studied 338 patients hospitalized for a first exacerbation of COPD in 9 Spanish hospitals, obtaining full occupational history in a face-to-face interview; job codes were linked to a job exposure matrix for semi-quantitative estimation of exposure to mineral/biological dust, and gases/fumes for each job held. Patients underwent spirometry, diffusing capacity testing and analysis of gases in stable conditions. Quality of life, dyspnea and chronic bronchitis symptoms were determined with a questionnaire interview. A high- resolution CT scan was available in 133 patients. RESULTS: 94% of the patients included were men, with a mean age of 68(8.5 years and a mean FEV1% predicted 52 (16. High exposure to gases or fumes was associated with chronic bronchitis, and exposure to mineral dust and gases/fumes was associated with higher scores for symptom perception in the St. George's questionnaire. No occupational agent was associated with a lower FEV1. High exposure to all occupational agents was associated with better lung diffusion capacity, in long-term quitters. In the subgroup with CT data, patients with emphysema had 18% lower DLCO compared to those without emphysema. CONCLUSIONS: In our cohort of COPD patients, high exposure to gases or fumes was associated with chronic bronchitis, and high exposure to all occupational agents was consistently associated with better diffusion capacity in long-term quitters.

  5. Evaluation of workers' exposure to total, respirable and silica dust and the related health symptoms in Senjedak stone quarry, Iran.

    Science.gov (United States)

    Golbabaei, Farideh; Barghi, Mohammad-Ali; Sakhaei, Manouchehr

    2004-01-01

    The present research was conducted in a stone quarry of marble located in northeast of Iran. Time weighted average of total dust, respirable dust, and crystalline silica (alpha-quartz) concentration in workers' breathing zone were monitored by using both gravimetric and XRD methods. The results showed that the employees working in hammer drill process had the highest exposure to the total and respirable dust: 107.9 +/- 8.0 mg/m3, 11.2 +/- 0.77 mg/m3 respectively, while the cutting machine workers had the lowest exposure (9.3 +/- 3.0 mg/m3, 1.8 +/- 0.82 mg/m3). The maximum concentration of a-quartz in total and respirable dust were detected equal to 0.670 +/- 8.49 x 10(-2) and 5.7 x 10(-2) +/- 1.6 x 10(-2) mg/m3 respectively, which belonged to the exposure of the workers of hammer drill process. The prevalence of skin and respiratory symptoms were higher in hammer drill workers, however, respiratory symptoms showed no significant prevalence. Regarding the average age of workers (31.6 +/- 1.9 yr) and average of their work history (3.8 +/- 1.0 yr), these results were predictable.

  6. Dust, endotoxin, fungi, and bacteria exposure as determined by work task, season, and type of plant in a flower greenhouse

    DEFF Research Database (Denmark)

    Thilsing, T.; Madsen, A. M.; Basinas, I.;

    2015-01-01

    of this study was to assess the occupational exposure in a flower greenhouse and to investigate the impact of work tasks on the intensity and variability in exposure. METHODS: Seventy-six personal full-shift exposure measurements were performed on 38 employees in a Danish flower greenhouse producing Campanula...... the greenhouse electronic task logging system. Associations between log-transformed exposure outcomes, season, and work tasks were examined in linear mixed-effects regression with worker identity as random effect. RESULTS: Measured concentrations ranged between 0.04 and 2.41mg m(-3) for inhalable dust...... or packing Rhipsalideae, and fungi exposure was elevated by subtasks performed in the research and development area for Campanula, and by potting, packing/dumping Campanula. Sticking and working with subtasks in the research and development area for Campanula increased bacteria exposure. CONCLUSION...

  7. Assessing the Effect of Cement Dust Emission on the Physicochemical Nature of Soil around Messebo area, Tigray, North Ethopia

    Directory of Open Access Journals (Sweden)

    SAMUEL ESTIFANOS

    2012-12-01

    Full Text Available Twenty six soil samples were collected around the vicinity of Messebo cement factory in Mekelle, Ethiopia from 0-5 and 5-15 cm depths and determined their physicochemical properties and heavy metals contents. The results indicated that the soils are calcareous having sandy loam to loamy sand texture. The top and lower parts of the soil are found to be alkaline with mean pH 8.97 and 8.93; EC 223.06 and 88.22 µS/cm respectively. The cation exchange capacity of the top soil (0-5cm range from 9 to 27 mmolc kg-1, while the exchangeable Ca and Mg range from 6.4 to 16 and 2.2 to 5.0 mmolc kg- 1 respectively. The average Ca concentration values for the upper and lower soil depths are 418ppm and 404.36ppm respectively. Water extractable analysis results verify the degree of leaching of the metals from anthropogenic source. Geoaccumulation index confirms that the two soil depths are similarly categorized as very heavily contaminated with (As, Cr, Co and Ni and moderately to heavily contaminated with (Cu, Pb and Mo whereas the top part is moderately contaminated with Zn. Based on Enrichment Factor (EF, both soil depths have moderate enrichment with Pb ( 2 EF >20, very high enrichment with Cr (2040. The severe contamination is evident to the east western direction towards which the wind blow predominantly.

  8. A study of New Zealand wood workers: exposure to wood dust, respiratory symptoms, and suspected cases of occupational asthma.

    Science.gov (United States)

    Norrish, A E; Beasley, R; Hodgkinson, E J; Pearce, N

    1992-05-27

    A randomly selected group of 50 New Zealand wood workers was studied. The level of airborne wood dust to which they were exposed ranged from 1.0-24.5 mg/m3. The wood workers reported experiencing higher rates of both lower and upper respiratory tract symptoms than a control group of office workers. Inhaled wood dust, in particular from rimu (Dacrydium cupressinum), was frequently cited by workers as being associated with respiratory tract symptoms. The wood workers' responses to the respiratory symptom questionnaire, and serial recordings of peak expiratory flow rate were used to screen the group for suspected cases of occupational asthma. Five cases fulfilled the study's criteria for suspected occupational asthma. In four of these, further evidence was found to support this diagnosis. We conclude that exposure to wood dust may cause occupational asthma in the woodworking industry in New Zealand.

  9. Job categories and their effect on exposure to fungal alpha-amylase and inhalable dust in the U.K. baking industry.

    Science.gov (United States)

    Elms, Joanne; Beckett, Paul; Griffin, Peter; Evans, Paul; Sams, Craig; Roff, Martin; Curran, Andrew D

    2003-01-01

    Enzymes in flour improver, in particular fungal alpha-amylase, are known to be a significant cause of respiratory allergy in the baking industry. This study measured total inhalable dust and fungal alpha-amylase exposures in U.K. bakeries, mills, and a flour improver production and packing facility and determined whether assignment of job description could identify individuals with the highest exposures to fungal alpha-amylase and inhalable dust. A total of 117 personal samples were taken for workers in 19 bakeries, 2 mills, and a flour improver production and packing facility and were analyzed using a monoclonal based immunoassay. Occupational hygiene surveys were undertaken for each site to assign job description and identify individuals who worked directly with flour improvers. Analysis of exposure data identified that mixers and weighers from large bakeries had the highest exposures to both inhalable dust and fungal alpha-amylase among the different categories of bakery workers (p<.01). Currently, the maximum exposure limit for flour dust in the United Kingdom is 10 mg/m(3) (8-hour time-weighted average reference period). In this study 25% of the total dust results for bakers exceeded 10 mg/m(3), and interestingly, 63% of the individuals with exposure levels exceeding 10 mg/m(3) were weighers and mixers. Individuals who worked directly with flour improvers were exposed to higher levels of both inhalable dust and fungal alpha-amylase (p<.01) than those who were not directly handling these products. Before sensitive immunoassays were utilized for the detection of specific inhalable allergens, gravimetric analysis was often used as a surrogate. There was a weak relationship between inhalable dust and fungal alpha-amylase exposures; however, inhalable dust levels could not be used to predict amylase exposures, which highlights the importance of measuring both inhalable dust and fungal alpha-amylase exposures.

  10. Occurrence and levels of polybrominated diphenyl ethers (PBDEs) in house dust and hair samples from Northern Poland; an assessment of human exposure.

    Science.gov (United States)

    Król, Sylwia; Namieśnik, Jacek; Zabiegała, Bożena

    2014-09-01

    Polybrominated diphenyl ethers (PBDEs) are among most ubiquitous compounds to be found in indoor environment and ingestion of household dust is considered an important route of exposure to PBDEs, especially in toddlers and young children. The present work reported concentration levels of PBDE congeners (PBDE-28, -47, -99, -100, -153, -154, -183 and -209) in hair and dust samples from selected households from Northern Poland. The concentrations of PBDEs in dust ranged from PBDEs via ingestion of household dust varied from 21 to 92ngd(-1) in toddlers and from 3.7 to 20ngd(-1) in adults. By comparison of correlation between the concentrations of PBDEs in paired hair and dust samples the present work also investigated the possibility of use of hair for reflecting the actual exposure to PBDEs in humans. Finally the possible uncertainties associated with exposure assessment were investigated in the present study.

  11. Children's Phthalate Intakes and Resultant Cumulative Exposures Estimated from Urine Compared with Estimates from Dust Ingestion, Inhalation and Dermal Absorption in Their Homes and Daycare Centers

    DEFF Research Database (Denmark)

    Bekö, Gabriel; Weschler, Charles J; Langer, Sarka

    2013-01-01

    . For each child the intake attributable to exposures in the indoor environment via dust ingestion, inhalation and dermal absorption were estimated from the phthalate levels in the dust collected from the child's home and daycare center. Based on the urine samples, DEHP had the highest total daily intake...

  12. Colorectal cancer and non-malignant respiratory disease in asbestos cement and cement workers. Studies on mortality, cancer morbidity, and radiographical changes in lung parenchyma and pleura

    Energy Technology Data Exchange (ETDEWEB)

    Jacobsson, K.

    1993-09-01

    Radiologically visible parenchymal changes (small opacities >= 1/0;ILO 1980 classification) were present in 20% of a sample of workers (N=174), employed for 20 years (median) in an asbestos cement plant. Exposure-response relationships were found, after controlling for age and smoking habits. In a sample of asbestos cement workers with symptoms and signs suggestive of pulmonary disease (N=33), increased lung density measured by x-ray computed tomography, and reduced static lung volumes and lung compliance was found. In a cohort of asbestos cement workers (N=1.929) with an estimated median exposure of 1.2 fibres/ml, the mortality from non-malignant respiratory disease was increased in comparison to a regional reference cohort (N=1.233). A two-to three-fold increase of non-malignant respiratory mortality was noted among workers employed for more than a decade in the asbestos cement plant, compared to cement workers (N=1.526), who in their turn did not experience and increased risk compared to the general population. In the cohorts of asbestos cement and cement workers, there was a tow-to three-fold increased incidence of cancer in the right part of the colon, compared to the general population as well as to external reference cohorts of other industrial workers (N=3.965) and fishermen (N=8.092). A causal relation with the exposure to mineral dust and fibres was supported by the findings of higher risk estimated in subgroups with high cumulated asbestos doses or longer duration of cement work. The incidence of cancer in the left part of the colon was not increased. Morbidity data, but not mortality data, disclosed the subsite-specific risk pattern. Both asbestos cement workers and cement workers has an increased incidence of rectal cancer, compared with the general population, and with the fishermen. The risk was, however, of the same magnitude among the other industrial workers. 181 refs.

  13. Simple Explanation on System Reform of Kiln Trail Dust Collector for 3000t/d Cement Production Line%浅谈3000t/d水泥生产线窑尾收尘系统改造

    Institute of Scientific and Technical Information of China (English)

    杨如顺; 吕忠明; 田源

    2012-01-01

      The paper presents the background, technical program, constructive program and engineering costs of system reform of kiln trail dust col ector for 3000t/d cement production line in Nanyang Hangtian Cement Plant. The fol owing program is:one similar bag dust col ector is paral el connected at the bag col ector with reversing blower and spun glass of high tempera-ture in original kiln trail, so as to increase the filtering area of kiln trail bag dust col ector and decrease the filtering wind speed. The reform shows an obvious result.%  介绍了南阳航天水泥厂3000t/d水泥生产线窑尾收尘系统的改造背景、技术方案、施工方案和工程造价。改造采用了在原窑尾反吹风高温玻纤袋收尘器旁并联一台同类型单排袋式收尘器的方案,以增大窑尾袋收尘器过滤面积和降低过滤风速。该窑尾收尘系统的改造取得了明显的成效。

  14. Dust exposure, eye redness, eye cytology and mucous membrane irritation in a tobacco industry

    DEFF Research Database (Denmark)

    Kjærgaard, Søren K.; Pedersen, O.F.

    1989-01-01

    In a study of 75 workers employed in a tobacco factory producing cheroots we measured cellular contents of tear fluid, redness of eyes, discomfort, total (0–5.7 mg/m3) and respirable dust in the breathing zone and total ambient dust by stationary sampling (0.08–1.0 mg/m3). A matched group of 50...

  15. Occurrence of Respiratory Symptoms Resulting from Exposure to House Dust Mites in Early Childhood

    Science.gov (United States)

    Jedrychowski, Wieslaw; Maugeri, Umberto; Zembala, Marek; Hajto, Barbara; Flak, Elzbieta; Mroz, Elzbieta; Jacek, Ryszard; Sowa, Agata; Perera, Frederica P.

    2009-01-01

    The aim of the study was to describe the distribution of house dust mite (HDM) allergens within homes of three-year-old children, to identify factors responsible for its variation and to test the hypothesis whether the content of HDM allergens exceeding 2 [mu]g/g dust may be regarded as a risk level of sensitization possibly affecting respiratory…

  16. Human lead (Pb) exposure via dust from different land use settings of Pakistan: A case study from two urban mountainous cities.

    Science.gov (United States)

    Eqani, Syed Ali Musstjab Akber Shah; Khalid, Ramsha; Bostan, Nazish; Saqib, Zafeer; Mohmand, Jawad; Rehan, Mohammad; Ali, Nadeem; Katsoyiannis, Ioannis A; Shen, Heqing

    2016-07-01

    The current study aims to determine the dust-borne lead (Pb) levels into outdoor dust, which were collected from the areas nearby the cities/districts of Islamabad and Swat in Pakistan. In general dust samples from all land use settings (industrial, urban and rural) showed significantly higher (patmospheric deposition from surrounding polluted areas. According to the calculated chemical daily intake (mg/kg-day) values, dust ingestion is one of the major routes of human exposure for lead. Hazard Index (HI) values, calculated for both adult and children populations, were above unity in industrial and urban areas, indicating serious health risks especially to the children populations.

  17. Evaluation of Quantitative Exposure Assessment Method for Nanomaterials in Mixed Dust Environments: Application in Tire Manufacturing Facilities.

    Science.gov (United States)

    Kreider, Marisa L; Cyrs, William D; Tosiano, Melissa A; Panko, Julie M

    2015-11-01

    Current recommendations for nanomaterial-specific exposure assessment require adaptation in order to be applied to complicated manufacturing settings, where a variety of particle types may contribute to the potential exposure. The purpose of this work was to evaluate a method that would allow for exposure assessment of nanostructured materials by chemical composition and size in a mixed dust setting, using carbon black (CB) and amorphous silica (AS) from tire manufacturing as an example. This method combined air sampling with a low pressure cascade impactor with analysis of elemental composition by size to quantitatively assess potential exposures in the workplace. This method was first pilot-tested in one tire manufacturing facility; air samples were collected with a Dekati Low Pressure Impactor (DLPI) during mixing where either CB or AS were used as the primary filler. Air samples were analyzed via scanning transmission electron microscopy (STEM) coupled with energy dispersive spectroscopy (EDS) to identify what fraction of particles were CB, AS, or 'other'. From this pilot study, it was determined that ~95% of all nanoscale particles were identified as CB or AS. Subsequent samples were collected with the Dekati Electrical Low Pressure Impactor (ELPI) at two tire manufacturing facilities and analyzed using the same methodology to quantify exposure to these materials. This analysis confirmed that CB and AS were the predominant nanoscale particle types in the mixing area at both facilities. Air concentrations of CB and AS ranged from ~8900 to 77600 and 400 to 22200 particles cm(-3), respectively. This method offers the potential to provide quantitative estimates of worker exposure to nanoparticles of specific materials in a mixed dust environment. With pending development of occupational exposure limits for nanomaterials, this methodology will allow occupational health and safety practitioners to estimate worker exposures to specific materials, even in scenarios

  18. Assessment of cancer and noncancer health risks from exposure to PAHs in street dust in the Tamale Metropolis, Ghana.

    Science.gov (United States)

    Obiri, Samuel; Cobbina, Samuel J; Armah, Frederick A; Luginaah, Isaac

    2013-01-01

    This study is part of a broader initiative to characterize, quantify and assess the human health risk associated with exposure to polycyclic aromatic hydrocarbons (PAHs) in street dust along the Trans-ECOWAS highway in West Africa. In the first part, PAHs were characterized and quantified in low- and high-traffic zones. In this study, cancer and noncancer human health risks from exposure to (PAHs) in street dust in the Tamale metropolis, Ghana were assessed in accordance with the USEPA risk assessment guidelines. The results of the study as obtained from inhalation of benzo [a] anthracene (BaA), benzo [a] pyrene (BaP), benzo [k] fluoranthene (BkF) and chrysene via central tendency exposure parameters (CTE) by trespassers (street hawkers including children and adults) in street dust within low traffic zones in the Tamale metropolis are 1.6E-02, 4.7E-02, 1.8E-03, and 1.6E-04 respectively. For reasonable maximum exposure parameters (RME), risk values of 1.2E-01, 3.5E-01, 1.3E-02 and 1.2E-03 respectively were obtained for benzo [a] anthracene, benzo [a] pyrene, benzo [k] fluoranthene and chrysene. Hazard index for acenaphthene, anthracene, fluoranthene, fluorine, naphthalene and pyrene in the CTE and RME scenarios were 2.2, 3.E-01, 2.6, 2.6, 100, 38 and 12, 1.7,15, 14, 550, 210 respectively. Generally, the cancer health risk associated with inhalation of benzo [a] anthracene, benzo [a] pyrene, benzo [k] fluoranthene and chrysene revealed that resident adults and children in the Tamale metropolis are at risk from exposure to these chemicals. The results of this preliminary assessment that quantified PAH related health risks along this part of the Trans-ECOWAS highway revealed that, there is the need for regulatory agencies to put in comprehensive measures to mitigate the risks posed to these categories of human receptors.

  19. [Exposure to ceramic fibers in the work environment. II. Occupational exposure to dust in plants producing ceramic fiber; fibrogenic effect of the fibers].

    Science.gov (United States)

    Wojtczak, J; Lao, I; Krajnow, A

    1996-01-01

    The aim of the work was to assess the exposure to dust containing ceramic fibres among workers employed in the plant producing aluminosilicate fibres, and to investigate fibrogenic properties of produced ceramic aluminosilicate fibres (L-1). The studies carried out in the work environment revealed that workers were exposed to dust containing respirable fibres from materials produced (fibres, mats). Mean concentrations of these fibres ranged from 0.07 to 0.37 f/cm3 and they were considerably lower than MAC value (1 f/cm3) proposed for respirable ceramic fibres. Mean total dust concentrations ranged from 0.4 to 2.9 mg/m3, and at two working posts they exceeded the proposed MAC value (2 mg/m3). In animal experiments (Wistar female rats) a single dose (25 mg) of L-1 fibres administered intratracheally induced pathological symptoms in lungs, limited to reactive changes in the form of granuloma with weakly pronounced cytolysis, and mean levels of hydroxyproline in the lungs did not differ significantly from the physiological level. The L-1 fibre was classified in the group of dusts with insignificant fibrogenic effects.

  20. Effectiveness of dust control methods for crystalline silica and respirable suspended particulate matter exposure during manual concrete surface grinding.

    Science.gov (United States)

    Akbar-Khanzadeh, Farhang; Milz, Sheryl A; Wagner, Cynthia D; Bisesi, Michael S; Ames, April L; Khuder, Sadik; Susi, Pam; Akbar-Khanzadeh, Mahboubeh

    2010-12-01

    Concrete grinding exposes workers to unacceptable levels of crystalline silica dust, known to cause diseases such as silicosis and possibly lung cancer. This study examined the influence of major factors of exposure and effectiveness of existing dust control methods by simulating field concrete grinding in an enclosed workplace laboratory. Air was monitored during 201 concrete grinding sessions while using a variety of grinders, accessories, and existing dust control methods, including general ventilation (GV), local exhaust ventilation (LEV), and wet grinding. Task-specific geometric mean (GM) of respirable crystalline silica dust concentrations (mg/m³ for LEV:HEPA-, LEV:Shop-vac-, wet-, and uncontrolled-grinding, while GV was off/on, were 0.17/0.09, 0.57/0.13, 1.11/0.44, and 23.1/6.80, respectively. Silica dust concentrations (mg/m³ using 100-125 mm (4-5 inch) and 180 mm (7 inch) grinding cups were 0.53/0.22 and 2.43/0.56, respectively. GM concentrations of silica dust were significantly lower for (1) GV on (66.0%) vs. off, and (2) LEV:HEPA- (99.0%), LEV:Shop-vac- (98.1%) or wet- (94.4%) vs. uncontrolled-grinding. Task-specific GM of respirable suspended particulate matter (RSP) concentrations (mg/m³ for LEV:HEPA-, LEV:Shop-vac-, wet-, and uncontrolled grinding, while GV was off/on, were 1.58/0.63, 7.20/1.15, 9.52/4.13, and 152/47.8, respectively. GM concentrations of RSP using 100-125 mm and 180 mm grinding cups were 4.78/1.62 and 22.2/5.06, respectively. GM concentrations of RSP were significantly lower for (1) GV on (70.2%) vs. off, and (2) LEV:HEPA- (98.9%), LEV:Shop-vac- (96.9%) or wet- (92.6%) vs. uncontrolled grinding. Silica dust and RSP were not significantly affected by (1) orientation of grinding surfaces (vertical vs. inclined); (2) water flow rates for wet grinding; (3) length of task-specific sampling time; or, (4) among cup sizes of 100, 115 or 125 mm. No combination of factors or control methods reduced an 8-hr exposure level to below the

  1. The effects of indoor and outdoor dust exposure on the growth, sensitivity to oxidative-stress, and biofilm production of three opportunistic bacterial pathogens.

    Science.gov (United States)

    Suraju, Mohammed O; Lalinde-Barnes, Sloan; Sanamvenkata, Sachindra; Esmaeili, Mahsa; Shishodia, Shishir; Rosenzweig, Jason A

    2015-12-15

    Within the last decade, many studies have highlighted the radical changes in the components of indoor and outdoor dust. For example, agents like automobile emitted platinum group elements and different kinds of organic phthalates and esters have been reported to be accumulating in the biosphere. Humans consistently face dermal, respiratory, and dietary exposures to these particles while indoors and outdoors. In fact, dust particulate matter has been associated with close to 500,000 deaths per year in Europe and about 200,000 deaths per year in the United States. To date, there has been limited examination of the physiological impact of indoor and outdoor dust exposure on normal flora microbes. In this study, the effect of indoor- and outdoor-dust exposure on three opportunistic bacterial species (Escherichia coli, Enterococcus faecalis, and Pseudomonas aeruginosa) was assessed. Specifically, bacterial growth, oxidative stress resistance, and biofilm production were measured following indoor- and outdoor-dust exposures. Studies were conducted in nutritionally-rich and -poor environments typically encountered by bacteria. Surprisingly, indoor-dust (200μg/mL), enhanced the growth of all three bacterial species in nutrient-poor conditions, but slowed growth in nutrient-rich conditions. In nutrient-rich medium, 100μg/mL exposure of either indoor- or outdoor-dust resulted in significantly reduced oxidative stress resistance in E. coli. Most interestingly, dust (indoor and outdoor), either in nutrient-rich or -poor conditions, significantly increased biofilm production in all three bacterial species. These data suggest that indoor and outdoor dust, can modify opportunistic bacteria through altering growth, sensitivity to oxidative stress, and their virulence potential through enhanced biofilm formation.

  2. A study on respiratory problems and pulmonary function indexes among cement industry workers in Mashhad, Iran

    Directory of Open Access Journals (Sweden)

    Ehsan Rafeemanesh

    2015-08-01

    Full Text Available Background: The respiratory system is the most vulnerable system in the cement industry. This study was conducted to determine the effects of occupational exposure to cement dust on the respiratory system more thoroughly. Material and Methods: In this cross sectional study an interviewer-administered questionnaire on socio-demographic characteristics and respiratory symptoms was completed and pulmonary function tests were carried out on 100 exposed and 120 non-exposed workers at the cement factory in Mashhad, Iran. The data was statistically analyzed by SPSS 16. Results: The mean of age and work duration in the exposed group was 37.5±6.3 and 10.7±5.4 years compared with the non-exposed group that was 36.1±7.1 and 10.1±5.7 years, respectively. Levels of exposure to inhalable cement dust in the exposed group were 23.13 mg/m3 (higher than national occupational exposure limits for such particles. Among the exposed group, respiratory symptoms as cough (6% vs. 0.8% of the non-exposed and sputum (7% vs. 0.8% of the nonexposed were significantly more prevalent (p < 0.05. Forced expiratory flow 25–75% (FEF25–75% was significantly lower in the exposed workers compared with non-exposed ones (p < 0.05. Also forced expiratory volume in 1 s / forced vital capacity (FEV1/FVC and FEF25–75% had a reverse correlation with the length of employment (p = 0.000 and p = 0.003, respectively. Conclusions: The findings of this study showed that occupational exposure to cement dust could be a significant factor of respiratory system dysfunction. Strict implementation of a respiratory protection program is recommended in cement industries. Med Pr 2015;66(4:471–477

  3. Exposure assessment of organophosphorus and organobromine flame retardants via indoor dust from elementary schools and domestic houses.

    Science.gov (United States)

    Mizouchi, Shigekazu; Ichiba, Masayoshi; Takigami, Hidetaka; Kajiwara, Natsuko; Takamuku, Toshiyuki; Miyajima, Toru; Kodama, Hiroki; Someya, Takashi; Ueno, Daisuke

    2015-03-01

    To assess the exposure of flame retardants (FRs) for school-children, organophosphorus flame retardants and plasticizers (PFRs) and organobromine flame retardants (BFRs) were determined in the indoor dust samples collected from elementary schools and domestic houses in Japan in 2009 and 2010. PFRs were detected in all the dust samples analyzed and the highest concentration of total PFRs was thousand-fold higher than that of BFRs. Among the PFRs, tris(butoxyethyl)phosphate (TBOEP) showed the highest concentration with a median (med.) of 270,000 ng g(-1) dry weight (3700-5,500,000 ng g(-1) dry weight), followed by tris(methylphenyl)phosphate (TMPPs)>triphenyl phosphate (TPHP)=tris(1,3-dichloro-2-propyl)phosphate (TDCIPP)=tris(2-chloroisopropyl)phosphate (TCIPP)=tris(2chloroethyl)phosphate (TCEP)>ethylhexyl diphenyl phosphate (EHDPP). Significantly higher concentrations of TBOEP, tri-n-butyl phosphate (TNBP), TPHP, TMPPs, and total-PFRs were found in dust samples from elementary schools than from domestic houses. It might be due to that higher concentrations of TBOEP (as leveling agent) were detected from the floor polisher/wax products collected in those elementary schools. On the other hand, significantly higher concentrations of TCEP, TCIPPs, and total chloroalkyl-PFRs were found in domestic houses than in elementary schools. Exposure assessments of PFRs via indoor dust from elementary schools and domestic houses were conducted by calculating the hazard quotient (HQ). Among PFRs, HQs for TBOEP exceeded 1 (higher than reference dose: RfD) and its highest value was 1.9. To reduce the intake of TBOEP by school-children, it is recommended that the use of floor polisher/wax containing TBOEP be reduced in schools.

  4. Cement Conundrum

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    China aims to streamline the crowded cement industry Policymakers are looking to build a concrete wall around the cement-making industry as they seek to solidify the fluid cement market and cut excessive production.

  5. Overview on relative importance of house dust ingestion in human exposure to polybrominated diphenyl ethers (PBDEs): International comparison and Korea as a case.

    Science.gov (United States)

    Kim, Seung-Kyu; Kim, Kyoung-Soo; Sang, Hee Hong

    2016-11-15

    Human exposure studies to polybrominated diphenyl ethers (PBDEs) have reached different results about the relative importance of diet intake and house dust ingestion. In the present study, concentrations of PBDEs in Korean house dust (n=15) from geographically different cities were measured, which were in agreement with a previous result, and compared with those for 22 countries of five continents collected from the most recent scientific literature. Compared with other exposure pathways, diet intake was the most important contributor to total PBDEs exposure of Korean adults (i.e., 71% of overall intake). On global comparison, total PBDE levels in house dust differed by two to three orders of magnitude among the countries investigated, with a significant relationship with gross domestic product (GDP). Whereas, dietary daily intakes exhibited a narrow difference within one order of magnitude worldwide and no relationship with GDP. Consequently, the relative importance of major two pathways depended on the contamination extent of PBDEs in house dust, which may be associated with the amount of PBDE products in use. In most countries except for UK and USA, the contribution of house dust ingestion was less important than diet intake in the current and are expected to much more mitigate in the future. However, how fast the effect of regulation will be reflected to house dust and human exposure is necessary to be monitored steadily.

  6. A study of pulmonary function test among tea garden factory workers in relation to exposure of tea dust

    Directory of Open Access Journals (Sweden)

    Birinchi Kartik Das

    2015-10-01

    Results: The investigator is interested to test whether there were significant differences between parameters of PFT among the study and control group. For this purpose student t test has been applied and significant differences were found in all the parameters of PFT as P < 0.01. Conclusions: Exposure to tea dust affects the lung volumes and flow rates, thereby causing increased prevalence of respiratory, allergic symptoms and significant degree of airway obstruction. [Int J Res Med Sci 2015; 3(10.000: 2686-2693

  7. New tools to monitor personal exposure to respirable coal mine dust

    Energy Technology Data Exchange (ETDEWEB)

    Volkwein, J.C.; Thimons, E.D. [NIOSH/Pittsburgh Research Laboratory, Pittsburgh, PA (USA)

    2001-07-01

    The compliance sampling method for coal mine dust in the United States has not changed appreciably in the last 30 years. A call for more frequent sampling with immediately available results is leading to new instruments that may supplement or replace the existing sampler. This report discusses two such instruments that provide immediate results of dust levels. The first, called the Respirable Dust Dosimeter (RDD), is designed to supplement the existing U. S. cyclone compliance sampling method. It uses the pressure drop across a filter to provide an inexpensive screening type of measurement. The RDD has been tested in the laboratory and a limited number of coal mines. Side by side testing has compared the RDD performance with personal coal mine samplers in triplicate area sample measurements. Results show that the differential pressure of specific filtration media can be an effective surrogate for respirable mass. Data show that there is a dependence on coal type and an effect of relative humidity. There also appear to be two distinct responses related to coal type. For specific coals the coefficients of determination, R{sub 2}, are better than 0.9. For general use the detector tube, using laboratory generated calibration curves, can be used to estimate respirable dust levels. However, a calibration to a specific coal type may substantially improve the accuracy. Another sampler in development is called the Personal Dust Monitor (PDM). Designed to give compliance quality accuracy, the PDM uses the frequency change of a vibrating element to measure dust and give immediate feedback of results. Results of laboratory comparison of the prototype PDM sampler to personal gravimetric samplers indicate R{sub 2} values of better than 0.99 for three different coal types. Work is in progress to package the components into a person-wearable unit combined with a cap lamp system with a total projected weight of less than 1.4 kg (3 lbs). 4 refs., 10 figs.

  8. Biomonitoring of industrial dusts on animals. II. Bioindication on alveolar macrophages.

    Science.gov (United States)

    Kaváciková, Z

    1986-01-01

    Rats and rabbits were exposed through the respiratory system to industrial dusts (magnesite emissions, solid wastes from nickel refinery dump, cement emissions) at biomonitory stations or in experimental chamber. Following exposure the animals were killed, the alveolar macrophages isolated and acid phosphatase and beta-glucuronidase estimated in the isolated cells. The activity of both enzymes was enhanced in the exposed animals in all cases. The enhancement was dependent on the length of exposure and amount of inhaled particles.

  9. Exposure Factors in Health Risk Assessment for Soil and Dust Exposure%土壤/尘健康风险评价中的暴露参数

    Institute of Scientific and Technical Information of China (English)

    王宗爽; 段小丽; 王贝贝; 王叶晴; 钱岩; 聂静; 张金良

    2012-01-01

    该文在参考美国暴露参数手册及国内外相关研究的基础上,总结了土壤/尘摄入率及皮肤黏附系数的研究方法,阐述不同土壤/尘摄入人群的分级定义,并对国外报道中各类人群土壤/尘摄入率及不同情境下的土壤/尘-皮肤黏附系数进行了归纳,为土壤暴露相关的健康风险评价提供资料参考.%Based on the US Exposure Factor Handbook and domestic and foreign related researches, the research methods of soil intake rate were described, the rating definition of different levels that people ingesting soil was defined. And then, exposure factors such as soil and dust intake rate, soil/dust -skin adhesion factor were stated, in order to provide recommendation to health risk assessment for the people exposed to environmental soil.

  10. Exposure to respirable dust and crystalline silica in bricklaying education at Dutch vocational training centers.

    NARCIS (Netherlands)

    Huizer, D.; Spee, T.; Lumens, M.E.G.L.; Kromhout, H.

    2010-01-01

    BACKGROUND: Construction workers are educated at vocational training centers before they begin their working lives. Future bricklayers and their instructors are exposed to respirable dust and possibly to hazardous respirable crystalline silica from trial mortar. METHODS: Thirty-six personal air samp

  11. Macrocyclic-, polycyclic-, and nitro musks in cosmetics, household commodities and indoor dusts collected from Japan: implications for their human exposure.

    Science.gov (United States)

    Nakata, Haruhiko; Hinosaka, Mari; Yanagimoto, Hayato

    2015-01-01

    This paper reported the occurrence and concentrations of macrocyclic-, polycyclic- and nitro musks in cosmetics and household commodities collected from Japan. The high concentrations and detection frequencies of Musk T, habanolide, and exaltolides were found in commercial products, suggesting their large amounts of production and usage in Japan. Polycyclic musks, HHCB and OTNE, also showed high concentrations in cosmetics and products. The estimated dairy intakes of Musk T and HHCB by the dermal exposure to commercial products were 7.8 and 7.9 μg/kg/day in human, respectively, and perfume and body lotion are dominant exposure sources. We also analyzed synthetic musks in house dusts. Polycyclic musks, HHCB and OTNE, showed high concentrations in samples, but macrocyclic musks were detected only in a few samples, although these types of musks were highly detected in commercial products. This is probably due to easy-degradation of macrocyclic musks in indoor environment. The dairy intakes of HHCB by dust ingestions were 0.22 ng/kg/day in human, which were approximately five orders of magnitudes lower than those of dermal absorption from commercial household commodities.

  12. Cellulosic building insulation versus mineral wool, fiberglass or perlite: installer's exposure by inhalation of fibers, dust, endotoxin and fire-retardant additives.

    Science.gov (United States)

    Breum, N O; Schneider, T; Jørgensen, O; Valdbjørn Rasmussen, T; Skibstrup Eriksen, S

    2003-11-01

    A task-specific exposure matrix was designed for workers installing building insulation materials. A priori, a matrix element was defined by type of task (installer or helper), type of work area (attic spaces or wall cavities) and type of insulation material (slabs from mineral wool, fiberglass or flax; loose-fill cellulosic material or perlite). In the laboratory a mock-up (full scale) of a one-family house was used for simulated installation of insulation materials (four replicates per matrix element). Personal exposure to dust and fibers was measured. The dust was analyzed for content of endotoxin and some trace elements (boron and aluminum) from fire-retardant or mold-resistant additives. Fibers were characterized as WHO fibers or non-WHO fibers. In support of the exposure matrix, the dustiness of all the materials was measured in a rotating drum tester. For installers in attic spaces, risk of exposure was low for inhalation of dust and WHO fibers from slab materials of mineral wool or fiberglass. Slab materials from flax may cause high risk of exposure to endotoxin. The risk of exposure by inhalation of dust from loose-fill materials was high for installers in attic spaces and for some of the materials risk of exposure was high for boron and aluminum. Exposure by inhalation of cellulosic WHO fibers was high but little is known about the health effects and a risk assessment is not possible. For the insulation of walls, the risk of installers' exposure by inhalation of dust and fibers was low for the slab materials, while a high risk was observed for loose-fill materials. The exposure to WHO fibers was positively correlated to the dust exposure. A dust level of 6.1 mg/m3 was shown to be useful as a proxy for screening exposure to WHO fibers in excess of 10(6) fibers/m3. In the rotating drum, slabs of insulation material from mineral wool or fiberglass were tested as not dusty. Cellulosic loose-fill materials were tested as very dusty, and perlite proved to be

  13. Occurrence of phthalate diesters (phthalates), p-hydroxybenzoic acid esters (parabens), bisphenol A diglycidyl ether (BADGE) and their derivatives in indoor dust from Vietnam: Implications for exposure.

    Science.gov (United States)

    Tran, Tri Manh; Minh, Tu Binh; Kumosani, Taha A; Kannan, Kurunthachalam

    2016-02-01

    Phthalate diesters (phthalates), esters of p-hydroxybenzoic acid (parabens), and bisphenol A diglycidyl ether (BADGE) are used in personal care products, food packages, household products, or pharmaceuticals. These compounds possess endocrine-disrupting potentials and have been reported to occur in the environment. Nevertheless, no previous studies have reported the occurrence of these compounds in indoor dust from Vietnam. In this study, nine phthalates, six parabens, and four BADGEs were determined in indoor dust samples collected from Hanoi, Hatinh, Hungyen, and Thaibinh, in Vietnam. Total concentrations of phthalates, parabens, and BADGEs in indoor dust ranged from 3440 to 106,000 ng/g (median: 22,600 ng/g), 40-840 ng/g (median: 123 ng/g), and 23 to 1750 ng/g (median: 184 ng/g), respectively. Based on the measured median concentration of phthalates, parabens, and BADGEs in indoor dust, we estimated human exposure doses to these compounds through indoor dust ingestion for various age groups. The exposure doses to phthalates, parabens, and BADGEs decreased with age and ranged from 19.4 to 90.4 ng/kg-bw/d, 0.113-0.528 ng/kg-bw/d, and 0.158-0.736 ng/kg-bw/d, respectively. This is the first study on the occurrence and human exposure of phthalates, parabens, and BADGEs in indoor dust from Vietnam.

  14. Utilizing TEMPO surface estimates to determine changes in emissions, community exposure and environmental impacts from cement kilns across North America using alternative fuels

    Science.gov (United States)

    Pegg, M. J.; Gibson, M. D.; Asamany, E.

    2015-12-01

    community exposure research in NA. The application of the new NASA TEMPO satellite to track the dispersion of SO2, PM2.5 and NO2 in plumes and secondary O3 and aerosol formation downwind of cement kilns opens up an exciting new avenue of air pollution research in NA.

  15. A GM-CSF/IL-33 pathway facilitates allergic airway responses to sub-threshold house dust mite exposure.

    Directory of Open Access Journals (Sweden)

    Alba Llop-Guevara

    Full Text Available Allergic asthma is a chronic immune-inflammatory disease of the airways. Despite aeroallergen exposure being universal, allergic asthma affects only a fraction of individuals. This is likely related, at least in part, to the extent of allergen exposure. Regarding house dust mite (HDM, we previously identified the threshold required to elicit allergic responses in BALB/c mice. Here, we investigated the impact of an initial immune perturbation on the response to sub-threshold HDM exposure. We show that transient GM-CSF expression in the lung facilitated robust eosinophilic inflammation, long-lasting antigen-specific Th2 responses, mucus production and airway hyperresponsiveness. This was associated with increased IL-33 levels and activated CD11b(+ DCs expressing OX40L. GM-CSF-driven allergic responses were significantly blunted in IL-33-deficient mice. IL-33 was localized on alveolar type II cells and in vitro stimulation of human epithelial cells with GM-CSF enhanced intracellular IL-33 independently of IL-1α. Likewise, GM-CSF administration in vivo resulted in increased levels of IL-33 but not IL-1α. These findings suggest that exposures to environmental agents associated with GM-CSF production, including airway infections and pollutants, may decrease the threshold of allergen responsiveness and, hence, increase the susceptibility to develop allergic asthma through a GM-CSF/IL-33/OX40L pathway.

  16. Brominated flame retardants in house dust from e-waste recycling and urban areas in South China: implications on human exposure.

    Science.gov (United States)

    Wang, Jing; Ma, Yun-Juan; Chen, She-Jun; Tian, Mi; Luo, Xiao-Jun; Mai, Bi-Xian

    2010-08-01

    Brominated flame retardants (BFRs) were examined in house dust from the electronic waste (e-waste) recycling and urban areas of South China. The concentrations of polybrominated diphenyl ethers (PBDEs) were in the range of 227-160,000 ng/g in the e-waste recycling area and 530-44,000 ng/g in the urban area. These values were much higher than other BFRs, except for novel decabromodiphenyl ethane (DBDPE) whose value of 100-47,000 ng/g was dominant in approximately 1/4 of the samples from the urban area. Urban dust PBDE levels were generally higher than those in many European and Asian countries and comparable to the values found in North America. Urban dust DBDPE levels were higher than those of other areas in the world. The distinct dust BFR profiles observed in the two studied areas were reflective of activities in these areas (electronics industry vs. e-waste recycling). The presence of BDE202, as well as the BDE197 to BDE201 and the nona-BDEs to deca-BDE ratios in the dust samples from the studied areas were probably indicative of environmental degradation of deca-BDE. The estimated daily intakes (EDIs) of average adult and toddler via house dust ranged from 37.0 to 304 ng/day for PBDEs and from 3.01 to 87.6 ng/day for all other BFRs in the studied areas. The EDIs via house dust were much higher than those via other indoor pathways (air, fish, human milk, and toys). Despite the potentially low deleterious risk of PBDE exposure via house dust as suggested by the hazard quotients, this exposure pathway should be of great concern because of the higher BFR exposures for children and the presence of other BFRs (such as DBDPE) which have not yet been fully investigated.

  17. Risk evaluation and exposure control of mineral dust containing free crystalline silica: a study case at a quarry in the Recife Metropolitan Area.

    Science.gov (United States)

    Lira, Mario; Kohlman Rabbani, E; Barkokébas Junior, Beda; Lago, Eliane

    2012-01-01

    During the production of aggregates at quarry sites, elevated quantities of micro-particulate mineral dust are produced in all stages of the process. This dust contains appreciable amounts of free crystalline silica in a variety of forms which, if maintained suspended in the air in the work environment, expose the workers to the risk of developing occupational silicosis, which causes reduced ability to work and potential shortening of lifespan. This study was conducted to qualitatively and quantitatively evaluate workers' exposure to mineral dust containing free crystalline silica at a midsized quarry in the Recife metropolitan area, in the State of Pernambuco. It involved evaluation of the industrial process, collection and analysis of representative dust samples, and interviews with the management team of the company with the intent to assess the compliance of the company with Regulatory Standard (NR) 22--Occupational safety and health in mining. In order to assist the company in managing risks related to dust exposure, three protocols were developed, implemented and made available, the first based on NR 22, from which the company was also given an economic safety indicator, the second based on the recommendations and requirements of Fundacentro to implement a Respiratory Protection Program and, finally, an assessment protocol with respect to the guidelines of the International Labor Organization to implement a health and safety management system. This study also showed the inadequacy of the formula for calculating tolerance limits in Brazilian legislation when compared with the more strict internationally accepted control parameters. From the laboratory results, unhealthy conditions at the quarry site were confirmed and technical and administrative measures were suggested to reduce and control dust exposure at acceptable levels, such as the implementation of an occupational health and safety management system, integrated with other management systems. From these

  18. Determinants of Wood Dust Exposure in the Danish Furniture Industry—Results from Two Cross-Sectional Studies 6 Years Apart

    Science.gov (United States)

    Schlünssen, Vivi; Jacobsen, Gitte; Erlandsen, Mogens; Mikkelsen, Anders B.; Schaumburg, Inger; Sigsgaard, Torben

    2008-01-01

    Objectives: This paper investigates determinants of wood dust exposure and trends in dust level in the furniture industry of Viborg County, Denmark, using data from two cross-sectional studies 6 years apart. Methods: During the winter 1997/1998, 54 factories were visited (hereafter study 1). In the winter 2003/2004, 27 factories were revisited, and personal dust measurements were repeated. In addition, 14 new factories were included (hereafter study 2). A total of 2303 woodworkers participated in study 1, and 2358 measurements from 1702 workers were available. From study 2, 1581 woodworkers participated and 1355 measurements from 1044 workers were available. Information on occupational variables describing potential determinants of exposures like work task, exhaust ventilation, enclosure and cleaning procedures were collected. A total of 2627 measurements and 1907 persons were included in the final mixed model in order to explore determinants of exposure and trends in dust level. Results: The overall inhalable wood dust concentration (geometric means (geometric standard deviation)) has decreased from 0.95 mg/m3 (2.05) in study 1 to 0.60 mg/m3 (1.63) in study 2, representing a 7% annual decrease in dust concentration, which was confirmed in the mixed model. From study 1 to study 2 there has been a change towards less manual work and more efficient cleaning methods, but on the contrary also more inadequate exhaust ventilation systems. The following determinants were found to ‘increase’ dust concentration: sanding; use of compressed air; use of full-automatic machines; manual work; cleaning of work pieces with compressed air; kitchen producing factories and small factories (industry in Viborg County, further improvements are possible. There should be more focus on improved exhaust ventilation, professional cleaning methods and avoiding use of compressed air. PMID:18407937

  19. Respirable coal dust exposure and respiratory symptoms in South-African coal miners: A comparison of current and ex-miners

    Energy Technology Data Exchange (ETDEWEB)

    Naidoo, R.N.; Robins, T.G.; Seixas, N.; Lalloo, U.G.; Becklake, M. [University of KwaZuluNatal, Congella (South Africa). Nelson R Mandela School of Medicine

    2006-06-15

    Dose-response associations between respirable dust exposure and respiratory symptoms and between symptoms and spirometry outcomes among currently employed and formerly employed South-African coal miners were investigated. Work histories, interviews, and spirometry and cumulative exposure were assessed among 684 current and 212 ex-miners. Results: Lower prevalences of symptoms were found among employed compared with ex-miners. Associations with increasing exposure for symptoms of phlegm and past history of tuberculosis were observed, whereas other symptom prevalences were higher in the higher exposure categories. Symptomatic ex-miners exhibited lower lung-function compared to the nonsymptomatic. Compared with published data, symptoms rates were low in current miners but high in ex-miners. Although explanations could include the low prevalence of smoking and/or reporting/selection bias, a 'Survivor' and/or a 'hire' effect is more likely, resulting in an underestimation of the dust-related effect.

  20. The effects of exposure to diesel fumes, low-level radiation and respirable dust and quartz on cancer mortality in coalminers

    Energy Technology Data Exchange (ETDEWEB)

    Miller, B.G.; Buchanan, D.; Hurley, J.F.; Robertson, A.; Hutchison, P.A.; Kidd, M.W.; Pilkington, A.; Soutar, C.A.

    1997-07-01

    Following findings of the British National Coal Board's Pneumoconiosis Field Research (PFR) major research programme into the health effects of respirable coal mine dust, a new programme was set up to identify and quantify any relationships between mortality from lung, stomach and other cancers, and exposure to respirable dust and quartz, diesel exhaust particulates from underground vehicles, and radon and thoron daughters. The cohort for analysis was 18,166 men, entering follow-up at various surveys from the 2nd to 6th round of the PFR programme. These contributed over 408,000 person-years at risk up to the end of 1992, and 7002 deaths. Investigations of exposure-response relationships for specific causes of death were based on comparisons within the cohort, using the general framework of Cox's proportional hazard regression models to adjust for age, smoking hazards, periods of cohort entry etc. Mortality from pneumoconiosis showed a clear relationship with exposure to respirable dust, which was a better predictor of risk than respirable quartz. Neither bladder cancer or leukaemia showed a significant relationship with any of the exposures. Stomach cancer risks were not related to dust or quartz exposure, nor to time spent in the industry, suggesting that the explanation for the raised Standardised Mortality Ratio lies elsewhere than in the conditions of work. In most of the analyses of lung cancer, there was no strong evidence of exposure effects. In one series of analyses, exposure to respirable quartz was related to lung cancer mortality at conventional levels of statistical significance, but the effect was strongly confounded with pit differences. A similar but weaker effect was observed with radiation exposures. These findings could be artefacts of other factors which differed between the working practices or surrounding environments of the collieries involved.

  1. Increased mortality in COPD among construction workers exposed to inorganic dust.

    Science.gov (United States)

    Bergdahl, I A; Torén, K; Eriksson, K; Hedlund, U; Nilsson, T; Flodin, R; Järvholm, B

    2004-03-01

    The aim of this study was to find out if occupational exposure to dust, fumes or gases, especially among never-smokers, increased the mortality from chronic obstructive pulmonary disease (COPD). A cohort of 317,629 Swedish male construction workers was followed from 1971 to 1999. Exposure to inorganic dust (asbestos, man-made mineral fibres, dust from cement, concrete and quartz), gases and irritants (epoxy resins, isocyanates and organic solvents), fumes (asphalt fumes, diesel exhaust and metal fumes), and wood dust was based on a job-exposure matrix. An internal control group with "unexposed" construction workers was used, and the analyses were adjusted for age and smoking. When all subjects were analysed, there was an increased mortality from COPD among those with any airborne exposure (relative risk 1.12 (95% confidence interval (CI) 1.03-1.22)). In a Poisson regression model, including smoking, age and the major exposure groups, exposure to inorganic dust was associated with an increased risk (hazard ratio (HR) 1.10 (95% CI 1.06-1.14)), especially among never-smokers (HR 2.30 (95% CI 1.07-4.96)). The fraction of COPD among the exposed attributable to any airborne exposure was estimated as 10.7% overall and 52.6% among never-smokers. In conclusion, occupational exposure among construction workers increases mortality due to chronic obstructive pulmonary disease, even among never-smokers.

  2. Pulmonary and gastrointestinal exposure to cadmium oxide dust in a battery factory

    Energy Technology Data Exchange (ETDEWEB)

    Adamsson, E.; Piscator, M.; Nogawa, K.

    1979-02-01

    The elimination of cadmium in feces was studied in a group of 15 male workers exposed to cadmium oxide dust in a nickel-cadmium battery factory. The elimination of cadmium in feces was on the average 619 and 268 microgram/day in seven smokers and eight nonsmokers, respectively. The cadmium concentrations in blood were significantly higher in smokers than in nonsmokers, both before and after one month of vacation. Among the smokers there was a significant decrease in the cadmium concentrations during the vacation period, but not among the nonsmokers. It was estimated that cadmium naturally occurring in food and cigarettes, cadmium excreted from the gastrointestinal tract, and cadmium transported from the lungs by mucocillary clearance to the gastrointestinal tract only could explain up to 100 microgram of the cadmium in the feces.

  3. Health risk assessment of exposure to polybrominated diphenyl ethers (PBDEs) contained in residential air particulate and dust in Guangzhou and Hong Kong

    Science.gov (United States)

    Wang, Wei; Zheng, Jinshu; Chan, Chuen-Yu; Huang, Min-juan; Cheung, Kwai Chung; Wong, Ming Hung

    2014-06-01

    Polybrominated diphenyl ethers (PBDEs) were measured in air particulate PM2.5 (less than 2.5 μm), TSP (Total Suspend Particle) and dust samples from different households of two major urban centers of Pearl River Delta (PRD). ∑PBDEs in PM2.5 of households in Guangzhou (GZ) (52.9-2.03 × 103 pg m-3 mean 239 pg m-3) were significantly higher than Hong Kong (HK) (0.25-160 pg m-3, mean 43.8 pg m-3). Higher ∑PBDEs occurred in indoor TSP, ranging between 117 and 1.14 × 103 pg m-3, with a median of 333 pg m-3. BDE-209 was the largest contributor to PBDEs contained in household dust, PM2.5 and TSP samples of GZ. Among the particles in household environment, PM2.5 accumulated the highest PBDEs, especially BDE-209. The constant Cparticle/Cdust values suggested that sorption is the dominant mechanism through which PBDEs are associated with settled dust and airborne particles. PBDEs were fairly uniform from urban sites to suburban sites, indicating the predominant indoor sources of PBDEs. Compared with indoor PM2.5, indoor dust ingestion made an important contribution of particle associated PBDEs exposure for adults (25 years old) and toddlers (1-2 years old). Non-dietary exposure dominated total PBDEs exposure, accounting for 91.8-99.0% exposure dose for toddlers and 45.1-82.2% for adults. Dust ingestion (69.3-96.1%) was the predominant PBDEs exposure route for toddlers.

  4. Cement Formation

    DEFF Research Database (Denmark)

    Telschow, Samira; Jappe Frandsen, Flemming; Theisen, Kirsten

    2012-01-01

    Cement production has been subject to several technological changes, each of which requires detailed knowledge about the high multiplicity of processes, especially the high temperature process involved in the rotary kiln. This article gives an introduction to the topic of cement, including...... an overview of cement production, selected cement properties, and clinker phase relations. An extended summary of laboratory-scale investigations on clinkerization reactions, the most important reactions in cement production, is provided. Clinker formations by solid state reactions, solid−liquid and liquid...

  5. Biomonitoring Study of Heavy Metals in Blood from a Cement Factory Based Community

    Directory of Open Access Journals (Sweden)

    Bank M.S.

    2014-07-01

    Full Text Available Little is known about the effects of cement factory pollution, emissions, and kiln dust on contaminant exposure in human populations, including school environments, in close proximity to these point sources. In Ravena, New York, USA and vicinity, environmental pollution from a local cement plant is considered significant and substantial according to the United States Environmental Protection Agency’s Toxic Release Inventory, published in 2006, 2007, and 2010. We hypothesized that cement factory based communities, such as the one in Ravena, NY, may be differentially exposed to heavy metals, including mercury, via dust, soil, and air in addition to any contributions from fish consumption, dental amalgams, smoking habits, and occupational exposures, etc. Here we report measurements of several heavy metals in blood (Pb, Cd, As, Hg, Se and Al and, for comparative purposes, total mercury in hair from a local (six-mile radius population of Caucasian adults and children. We also report and synthesize local atmospheric emissions inventory information and new indoor air data (NYSERDA, 2011 from the local school which is situated directly across the street (within 750 feet from the cement factory and quarry. In addition, to our human and environmental heavy metal results we also discuss scientific outreach coordination, and public health action opportunities that will likely have wide applicability for other community and environmental health studies confronting similar pollution issues.

  6. Effects of Mikania glomerata Spreng. and Mikania laevigata Schultz Bip. ex Baker (Asteraceae) extracts on pulmonary inflammation and oxidative stress caused by acute coal dust exposure

    Energy Technology Data Exchange (ETDEWEB)

    Freitas, T.P.; Silveira, P.C.; Rocha, L.G.; Rezin, G.T.; Rocha, J.; Citadini-Zanette, V.; Romao, P.T.; Dal-Pizzol, F.; Pinho, R.A.; Andrade, V.M.; Streck, E.L. [University Extremo Catarinense, Criciuma (Brazil)

    2008-12-15

    Several studies have reported biological effects of Mikania glomerata and Mikania laevigata, used in Brazilian folk medicine for respiratory diseases. Pneumoconiosis is characterized by pulmonary inflammation caused by coal dust exposure. In this work, we evaluated the effect of pretreatment with M. glomerata and M. laevigata extracts (MGE and MLE, respectively) (100 mg/kg, s.c.) on inflammatory and oxidative stress parameters in lung of rats subjected to a single coal dust intratracheal instillation. Rats were pretreated for 2 weeks with saline solution, MGE, or MLE. On day 15, the animals were anesthetized, and gross mineral coal dust or saline solutions were administered directly in the lung by intratracheal instillation. Fifteen days after coal dust instillation, the animals were killed. Bronchoalveolar lavage (BAL) was obtained; total cell count and lactate dehydrogenase (LDH) activity were determined. In the lung, myeloperoxidase activity, thiobarbituric acid-reactive substances (TBARS) level, and protein carbonyl and sulfhydryl contents were evaluated. In BAL of treated animals, we verified an increased total cell count and LDH activity. MGE and MLE prevented the increase in cell count, but only MLE prevented the increase in LDH. Myeloperoxidase and TBARS levels were not affected, protein carbonylation was increased, and the protein thiol levels were decreased by acute coal dust intratracheal administration. The findings also suggest that both extracts present an important protective effect on the oxidation of thiol groups. Moreover, pretreatment with MGE and MLE also diminished lung inflammatory infiltration induced by coal dust, as assessed by histopathologic analyses.

  7. Effectiveness of interventions to reduce flour dust exposures in supermarket bakeries in South Africa

    NARCIS (Netherlands)

    Baatjies, Roslynn; Meijster, Tim; Heederik, Dick; Sander, Ingrid; Jeebhay, Mohamed F.

    2014-01-01

    Rationale: A recent study of supermarket bakery workers in South Africa demonstrated that 25% of workers were sensitised to flour allergens and 13% had baker's asthma. Evidence on exposure reduction strategies using specifically designed interventions aimed at reducing the risk of baker's asthma is

  8. [Polychlorinated biphenyls in house dust at an e-waste site and urban site in the Pearl River Delta, southern China: sources and human exposure and health risks].

    Science.gov (United States)

    Zhu, Zhi-Cheng; Chen, She-Jun; Ding, Nan; Wang, Jing; Luo, Xiao-Jun; Mai, Bi-Xian

    2014-08-01

    Polychlorinated biphenyls (PCBs) were measured in house dust from an e-waste site and urban site in the Pearl River Delta, southern China. The PCB concentrations in house dust at the e-waste site ranged from 12.4 to 87 765 ng x g(-1), with an average of 10 167 ng x g(-1). There was no significant difference in the PCB concentrations between indoor and outdoor dust. The PCB homologue pattern was dominated by tri-, penta-, hexa-, and tetra-CBs, which was not similar to that in Chinese technical PCB product. There was also no significant difference in the PCB compositions between indoor and outdoor dust. PCB sources in house dust at the e-waste site were apportioned by chemical mass balance (CMB) model. The results showed that the PCBs were derived primarily from Aroclor 1262 (36.7% ), Aroclor 1254 (26.7%), Aroclor 1242 (21.4%), and Aroclor 1248 (18.5%). The daily exposure doses were 42, 17, and 2.9 ng x (kg x d)(-1) for toddlers, children/adolescents, and adults in the e-waste area, respectively. Risk assessment indicated that the hazard quotients were higher than 1 for toddlers and children/adolescents indicating adverse effects for them. The lifetime average excess carcinogenic risk for population in the e-waste area was 4.5 x 10(-5), within the acceptable range of U. S. Environmental Protection Agency. The mean concentrations of PCBs in house dust in Guangzhou was 48.7 ng x g(-1). The low PCB level is consistent with the fact that technical PCBs were not widely used in China in the past. The risks of exposure to PCBs via house dust in Guangzhou are very low.

  9. Contamination of indoor dust and air by polychlorinated biphenyls and brominated flame retardants and relevance of non-dietary exposure in Vietnamese informal e-waste recycling sites.

    Science.gov (United States)

    Tue, Nguyen Minh; Takahashi, Shin; Suzuki, Go; Isobe, Tomohiko; Viet, Pham Hung; Kobara, Yuso; Seike, Nobuyasu; Zhang, Gan; Sudaryanto, Agus; Tanabe, Shinsuke

    2013-01-01

    This study investigated the occurrence of polychlorinated biphenyls (PCBs), and several additive brominated flame retardants (BFRs) in indoor dust and air from two Vietnamese informal e-waste recycling sites (EWRSs) and an urban site in order to assess the relevance of these media for human exposure. The levels of polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), 1,2-bis-(2,4,6-tribromophenoxy)ethane (BTBPE) and decabromodiphenyl ethane (DBDPE) in settled house dust from the EWRSs (130-12,000, 5.4-400, 5.2-620 and 31-1400 ng g(-1), respectively) were significantly higher than in urban house dust but the levels of PCBs (4.8-320 ng g(-1)) were not higher. The levels of PCBs and PBDEs in air at e-waste recycling houses (1000-1800 and 620-720 pg m(-3), respectively), determined using passive sampling, were also higher compared with non-e-waste houses. The composition of BFRs in EWRS samples suggests the influence from high-temperature processes and occurrence of waste materials containing older BFR formulations. Results of daily intake estimation for e-waste recycling workers are in good agreement with the accumulation patterns previously observed in human milk and indicate that dust ingestion contributes a large portion of the PBDE intake (60%-88%), and air inhalation to the low-chlorinated PCB intake (>80% for triCBs) due to their high levels in dust and air, respectively. Further investigation of both indoor dust and air as the exposure media for other e-waste recycling-related contaminants and assessment of health risk associated with exposure to these contaminant mixtures is necessary.

  10. Pulmonary and gastrointestinal exposure to cadmium oxide dust in a battery factory.

    Science.gov (United States)

    Adamsson, E; Piscator, M; Nogawa, K

    1979-02-01

    The elimination of cadmium in feces was studied in a group of 15 male workers exposed to cadmium oxide dust in a nickel-cadmium battery factory. The elimination of cadmium in feces was on the average 619 and 268 microgram/day in seven smokers and eight nonsmokers, respectively. The corresponding ranges were 97-2577 and 31-1102 microgram/day. The cadmium concentrations in blood were significantly higher in smokers than in nonsmokers, both before and after one month of vacation. Among the smokers there was a significant decrease in the cadmium concentrations during the vacation period, but not among the nonsmokers. It was estimated that cadmium naturally occurring in food and cigarettes, cadmium excreted from the gastrointestinal tract, and cadmium transported from the lungs by mucocillary clearance to the gastrointestinal tract only could explain up to 100 microgram of the cadmium in the feces. Since even among some nonsmokers much higher values for fecal cadmium were recorded, this was interpreted as being the result of ingestion of cadmium from contaminated hands and other body surfaces. Among the smokers, direct oral contact with contaminated cigarettes or pipes is an additional factor; the smokers also inhale cadmium in the tobacco smoke from contaminated cigarettes. Part of that cadmium is transferred to the gastrointestinal tract by mucociliary clearance and also adds to the fecal cadmium.

  11. Exploring hotspots of pneumococcal pneumonia and potential impacts of ejecta dust exposure following the Christchurch earthquakes.

    Science.gov (United States)

    Pearson, Amber L; Kingham, Simon; Mitchell, Peter; Apparicio, Philippe

    2013-12-01

    The etiology of pneumococcal pneumonia (PP) is well-known. Yet, some events may increase its incidence. Natural disasters may worsen air quality, a risk factor for PP. We investigated spatial/spatio-temporal clustering of PP pre- and post-earthquakes in Christchurch, New Zealand. The earthquakes resulted in deaths, widespread damage and liquefaction ejecta (a source of air-borne dust). We tested for clusters and associations with ejecta, using 97 cases (diagnosed 10/2008-12/2011), adjusted for age and area-level deprivation. The strongest evidence to support the potential role of ejecta in clusters of PP cases was the: (1) geographic shift in the spatio-temporal cluster after deprivation adjustment to match the post-earthquake clusters and; (2) increased relative risk in the fully-adjusted post-earthquake compared to the pre-earthquake cluster. The application of spatial statistics to study PP and ejecta are novel. Further studies to assess the long-term impacts of ejecta inhalation are recommended particularly in Christchurch, where seismic activity continues.

  12. Fluoride Release From Three Different Types of Giass- lonomer Cements After Exposure to Acidic and Neutral NaF Solution

    Directory of Open Access Journals (Sweden)

    Kousari A

    2000-06-01

    Full Text Available The purpose of this study was to assess the fluoride release of three fluoride- containing materials exposed to fluoride solutions. This study compared the initial fluoride release and release following re-fluoridation (neutral or acidic 2% NaF of three different filling materials, conventional glass ionomer cement (CG1C, resin- modified glass ionomer cement (RMGIC, polyacid- modified composite resin (PAMCR. Twenty discs of each material, measuring 2mm height and 6mm diameter, were suspended in separate vials of 2" laboratory artificial saliva. The amount of fluoride release was measured over two periods of 28 days each. Fluoride release was determined at 1,3,7,14 and 28 days of each period. Fluoride was measured with a fluoride ion- specific electrode and an ion analyzer previously calibrated with standard solution .T- test and ANOVA were used to evaluate the data. Fluoride release for all products at days 1 and 3 was significantly greater than the rest of the time intervals. Then, the fluoride release decreased significantly. CGIC released significantly more fluoride than the other products. This was followed by RMGIC, which exhibited significantly more fluoride release than PAMCR. In second period of experiment, the specimens were assigned to two subgroups often each. The samples exposed to two different solution of NaF (neutral or acidic. All groups showed the capacity of re-fluoridation and fluoride uptake. The specimens exposed to acidic NaF solution showed statistically more significant rechargeability than the neutral NaF solution. It may be concluded that glass ionomer cements act as a rechargeable slow fluoride release systems and as an effective caries preventive material in caries preventing programs for caries susceptible children.

  13. Historical exposure levels of inhalable dust in the Polish rubber industry compared to levels in Western Europe

    Science.gov (United States)

    de Vocht, F.; Kromhout, H.; Sobala, W.; Peplonska, B.

    2009-02-01

    Although studies have been carried out to assess inhalable dust exposure levels in the rubber manufacturing industry, the levels of exposure in factories in Eastern Europe are less well documented. Routine stationary sampling for compliance testing of inhalable aerosols has however been conducted in a large factory producing tires and tubes in Poland between 1981 and 1996 (N=6,152). This study was conducted to assess historical inhalable aerosol levels in different departments in this rubber plant and to compare the results with estimates based on European data from the UK, Sweden, the Netherlands and Germany, and also Poland (EXASRUB project). Geometric mean (GM) concentrations in the factory ranged from 2.41 mg/m3 to 5.82 mg/m3 and were to a large extent associated to the actual production capacity of the plant and flow of the production process. Whereas 3-4 fold differences between departments existed prior to about 1985, stronger reduction of exposure in the raw materials and finishing departments (-12%/year) compared to other departments (range -5%/yr to -3%/yr), resulted in comparable levels in the 1990s. However, in the pre-treating departments, average concentrations were still about a factor 2-3 higher than in other departments, which could presumably be attributed to the use of anti-tacking agents. GM concentrations have been modelled using (1) stationary measurements collected in the Polish factory only, or (2) all European data collected in the EXASRUB project. Comparison of the estimates showed that these were fairly similar for both datasets. This analysis showed that the levels of inhalable aerosols in the Polish rubber industry have been at least a factor three to four higher than in Western European countries in the 1980s and 1990s, depending on the department, but that these differences were getting smaller in the 1990s. Furthermore, the estimates based on all European data from EXASRUB provides valid estimates compared to factory-specific data.

  14. Pulmonary exposure to particles from diesel exhaust, urban dust or single-walled carbon nanotubes and oxidatively damaged DNA and vascular function in apoE(-/-)mice

    DEFF Research Database (Denmark)

    Vesterdal, Lise K; Jantzen, Kim; Sheykhzade, Majid;

    2012-01-01

    Abstract This study compared the oxidative stress level and vasomotor dysfunction after exposure to urban dust, diesel exhaust particles (DEP) or single-walled carbon nanotubes (SWCNT). DEP and SWCNT increased the production of reactive oxygen species (ROS) in cultured endothelial cells......, Hmox-1 and Ogg1. The levels of oxidatively damaged DNA were unchanged in lung tissue. The exposure to SWCNT significantly increased the expression of Ccl-2 in the lung tissue of the mice. The exposure to DEP and SWCNT was associated with elevated ROS production in cultured cells, whereas intratracheal...

  15. Respiratory consequences of exposure to wood dust and formaldehyde of workers manufacturing oriented strand board.

    Science.gov (United States)

    Herbert, F A; Hessel, P A; Melenka, L S; Yoshida, K; Nakaza, M

    1994-01-01

    A cross-sectional study was performed at a plant in which 99 workers were employed in the manufacture of oriented strand board. This group was compared with 165 unexposed workers from the petroleum industry. Both groups were assessed, using a questionnaire, spirometry, and skin prick tests to common environmental antigens. Environmental studies showed a low dust level of 0.27 mg/m3, consisting of particles of a mass median aerodynamic equivalent diameter of 2.5 microns. There were variable concentrations of formaldehyde, up to 0.27 ppm. A significant difference between the oriented strand board workers and oil field workers was noted for the forced expiratory volume in 1 s/forced vital capacity ratio, without significant differences in either the forced expiratory volume in 1 s or the forced vital capacity. Oriented strand board workers who were current smokers were three times as likely to have a forced expiratory volume in 1 s/forced vital capacity ratio of less than 75% of that found in the currently smoking oil field workers. Significant reductions in forced expiratory volume in 1 s (p = .044) and forced vital capacity (p = .022) in oriented strand board workers were noted across the work shift. The oriented strand board workers complained of self-reported asthma and of lower respiratory tract symptoms significantly more frequently than did oil workers for all of the symptoms examined. The prevalence of atopy was not different in the two groups. Lung function was significantly better in oriented strand board workers who had no symptoms, compared with oriented strand board workers who were symptomatic.(ABSTRACT TRUNCATED AT 250 WORDS)

  16. [Evaluating exposure of population to dust, with consideration of components and dispersion contents of industrial discharges from enterprise extracting and processing mineral raw materials (discussion)].

    Science.gov (United States)

    Mai, I V; Zagorodnov, S Iu; Popova, E V

    2014-01-01

    The article covers results of study concerning disperse content of solid components of discharges from main dust- generating technologic operations in extraction and processing of mineral raw materials (pouring ore to conveyor, drying with combustion gas in fluid-bed, pouring of end product, sorting ore on riddle, drying on vibration dry and cool device, etc). Findings are that fractions under 10 and 2.5 micrometers approach 50% in general structure of dust discharges. Maximal share of low-disperse dust enters ambient air from vibraion dry and cool devices, riddles and pouring places. Exceeded reference values for acute and chronic exposure are registered on TSP and PM10 at a sanitary protection zone border and in the nearest living area points--that can forecast intolerable risks for health of population exposed and necessitate instrumental confirmation of the detected jeopardy level.

  17. Children's phthalate intakes and resultant cumulative exposures estimated from urine compared with estimates from dust ingestion, inhalation and dermal absorption in their homes and daycare centers.

    Directory of Open Access Journals (Sweden)

    Gabriel Bekö

    Full Text Available Total daily intakes of diethyl phthalate (DEP, di(n-butyl phthalate (DnBP, di(isobutyl phthalate (DiBP, butyl benzyl phthalate (BBzP and di(2-ethylhexyl phthalate (DEHP were calculated from phthalate metabolite levels measured in the urine of 431 Danish children between 3 and 6 years of age. For each child the intake attributable to exposures in the indoor environment via dust ingestion, inhalation and dermal absorption were estimated from the phthalate levels in the dust collected from the child's home and daycare center. Based on the urine samples, DEHP had the highest total daily intake (median: 4.42 µg/d/kg-bw and BBzP the lowest (median: 0.49 µg/d/kg-bw. For DEP, DnBP and DiBP, exposures to air and dust in the indoor environment accounted for approximately 100%, 15% and 50% of the total intake, respectively, with dermal absorption from the gas-phase being the major exposure pathway. More than 90% of the total intake of BBzP and DEHP came from sources other than indoor air and dust. Daily intake of DnBP and DiBP from all exposure pathways, based on levels of metabolites in urine samples, exceeded the Tolerable Daily Intake (TDI for 22 and 23 children, respectively. Indoor exposures resulted in an average daily DiBP intake that exceeded the TDI for 14 children. Using the concept of relative cumulative Tolerable Daily Intake (TDI(cum, which is applicable for phthalates that have established TDIs based on the same health endpoint, we examined the cumulative total exposure to DnBP, DiBP and DEHP from all pathways; it exceeded the tolerable levels for 30% of the children. From the three indoor pathways alone, several children had a cumulative intake that exceeded TDI(cum. Exposures to phthalates present in the air and dust indoors meaningfully contribute to a child's total intake of certain phthalates. Such exposures, by themselves, may lead to intakes exceeding current limit values.

  18. Relationship between dust exposure and chronic obstructive pulmonary diseases and heat shock protein 72 and 73 in lymphocytes among coal miners

    Energy Technology Data Exchange (ETDEWEB)

    Xing J.C.; Chen W.H.; Wang F.; Han W.H.; Ren H.M; ; Wu T.C. [Huazhong University of Science and Technology, Wuhan (China). MOE Key Laboratory of Environmental Health, School of Public Health

    2006-09-15

    To assess the expression of Hsp72 and Hsp73 in chronic obstructive pulmonary disease (COPD) and to evaluate their roles in damage from coal dust exposure. A case control study of 50 coal miners suffering from COPD and 50 healthy coal miners were selected from one coal mine. The levels of Hsp72 and Hsp73 in peripheral blood lymphocytes were determined by flow cytometry for all subjects. The expression of basic Hsp72 of peripheral blood lymphocytes for patients and controls was not different from that inducible expressed Hsp72 by 42 degrees C heat stress or by BPDE exposure. (2) The expression of Hsp72 in COPD patients was significantly lower than that in healthy coal miners. On the other hand, the expression of Hsp73 in COPD patients was higher than that in healthy coal miners. (3) A-positive relationship between the expression of Hsp72 and cumulative inhaling coal dust exposure was observed. No relationship was found between Hsp73 and cumulative inhaling coal dust exposure. The decreased expressions of Hsp72 in peripheral blood lymphocytes of COPD coal miners.

  19. Properties of Portland cement concretes containing pozzolanic admixtures

    Science.gov (United States)

    Simmons, D. D.; Pasko, T. J., Jr.; Jones, W. R.

    1981-04-01

    A laboratory comparison was made of the properties of a concrete containing no pozzolan with several mixtures containing pozzolans. Used were a natural pozzolan (Lassenite), two fly ashes of different fineness and low carbon and an amorphous silica fume dust from a metal-producing plant. One cement, one coarse crushed limestone aggregate, and one fine river aggregate were used. Replacing a faster reacting binder with a slower one, produced lower early strengths and adversely affected the properties which are highly dependent on strength. The measures of durability were greatly affected by the air contents and aging or treatment prior to exposure. The amorphous silica fume dust increased the early strengths of a fly ash mixture.

  20. Mechanisms of metal dusting corrosion

    DEFF Research Database (Denmark)

    Hummelshøj, Thomas Strabo

    In this thesis the early stages of metal dusting corrosion is addressed; the development of carbon expanded austenite, C, and the decomposition hereof into carbides. Later stages of metal dusting corrosion are explored by a systematic study of stainless steel foils exposed to metal dusting...... influence of oxygen and carbon on the metal dusting corrosion is explored. The results indicate that exposure to metal dusting conditions have a detrimental effect on the resistance against oxidation and, conversely, that exposure to oxidation has a detrimental effect on the resistance towards metal dusting....... Consequently, a combination of carburizing and oxidizing conditions has a strong mutual catalyzing effect on the metal dusting corrosion....

  1. Prevalence and determinants of mucous membrane irritations in a community near a cement factory in Zambia: a cross sectional study.

    Science.gov (United States)

    Nkhama, Emmy; Ndhlovu, Micky; Dvonch, J Timothy; Siziya, Seter; Voyi, Kuku

    2015-01-16

    Exposure to cement dust has been associated with deleterious health effects in humans. This study investigated whether residing near a cement factory increases the risk of irritations to the mucous membranes of the eyes and respiratory system. A cross sectional study was conducted in Freedom Compound, a community bordering a cement factory in Chilanga, Zambia and a control community, Bauleni, located 18 km from the cement plant. A modified American Thoracic Society questionnaire was administered to 225 and 198 respondents aged 15-59 years from Freedom and Bauleni, respectively, to capture symptoms of the irritations. Respondents from Freedom Compound, were more likely to experience the irritations; adjusted ORs 2.50 (95% CI: 1.65, 3.79), 4.36 (95% CI (2.96, 6.55)) and 1.94 (95% CI (1.19, 3.18)) for eye, nose and sinus membrane irritations respectively. Cohort panel studies to determine associations of cement emissions to mucous membrane irritations and respiratory symptoms, coupled with field characterization of the exposure are needed to assess whether the excess prevalence of symptoms of mucous membrane irritations observed in Freedom compound are due to emissions from the cement factory.

  2. [Particle Size Distribution, Seasonal Variation Characteristics and Human Exposure Assessment of Heavy Metals in Typical Settled Dust from Beijing].

    Science.gov (United States)

    Cao, Zhi-guo; Yu, Gang; Lü, Xiang-ying; Wang, Meng-lei; Li, Qi-lu; Feng, Jing-lan; Yan, Guang-xuan; Yu, Hao; Sun, Jian-hui

    2016-04-15

    Four types of dust from dormitories, offices, hotels and roads in Beijing were collected and fractionated into 9 fractions, respectively. Totally 36 samples were obtained and analyzed for heavy metals including Cu, Zn, Cr, Pb, Cd and Ni. Particle size distributions of those heavy metals in these four types of dust were investigated and the influencing mechanisms were discussed. Distribution patterns of the same heavy metal in different types of dust showed various characteristics. Also different metals in the same type of dust represented different distribution patterns. Heavy metals in road dust tended to concentrate in finer particles. Two offices from the same building, located in Beijing, China, were selected to study the seasonality of heavy metals in dust. Dust sampling from Office A was conducted at weekly intervals between March 2012 and August 2012, while dust from Office B was sampled fortnightly from March 2012 to December 2012. Generally, levels of all heavy metals remained stable among different seasons, however, Cr and Pb represented more significant fluctuations than other four heavy metals. Based on the geo-accumulation index method, the pollution of Zn, Cu and Pb was more serious in the investigated samples, and dust from offices and hotels were moderately polluted by Zn. According to the risk assessment results, the carcinogenic health risks of the six heavy metals in the four types of dust were negligible.

  3. Domestic mite antigens in floor and airborne dust at workplaces in comparison to living areas: a new immunoassay to assess personal airborne allergen exposure.

    Directory of Open Access Journals (Sweden)

    Ingrid Sander

    Full Text Available OBJECTIVES: Allergens produced by domestic mites (DM are among the most common allergic sensitizers and risk factors for asthma. To compare exposure levels between workplaces and living areas a new assay able to measure airborne DM antigen concentrations was developed. METHODS: At workplaces and in living areas, 213 floor dust samples and 92 personal inhalable dust samples were collected. For sensitive quantification of DM antigens, a new enzyme immunoassay (EIA based on polyclonal antibodies to Dermatophagoides farinae extract was developed. Reactivity of five house dust mite and four storage mite species was tested. All dust samples were tested with the new EIA and with the Der f 1 and Der p 1-EIAs (Indoor Biotechnologies, UK which detect major allergens from D. farinae and D. pteronyssinus by monoclonal antibodies. Samples below the detection limit in the DM-EIA were retested in an assay variant with a fluorogenic substrate (DM-FEIA. RESULTS: The newly developed DM-EIA detects antigens from all nine tested domestic mite species. It has a lower detection limit of 200 pg/ml of D.farinae protein, compared to 50 pg/ml for the DM-FEIA. DM antigens were detected by DM-EIA/FEIA in all floor dust and 80 (87% of airborne samples. Der f 1 was found in 133 (62% floor dust and in only 6 airborne samples, Der p 1 was found in 70 (33% of floor samples and in one airborne sample. Der f 1 and DM concentrations were highly correlated. DM-antigens were significantly higher in inhalable airborne samples from textile recycling, bed feather filling, feed production, grain storage and cattle stables in comparison to living areas. CONCLUSIONS: A new sensitive EIA directed at DM antigens was developed. DM antigen quantities were well correlated to Der f 1 values and were measurable in the majority (87% of airborne dust samples. Some workplaces had significantly higher DM antigen concentrations than living areas.

  4. Flame retardants and organochlorines in indoor dust from several e-waste recycling sites in South China: composition variations and implications for human exposure.

    Science.gov (United States)

    Zheng, Xiaobo; Xu, Fuchao; Chen, Kehui; Zeng, Yanhong; Luo, Xiaojun; Chen, Shejun; Mai, Bixian; Covaci, Adrian

    2015-05-01

    Several classes of flame retardants, such as polybrominated diphenyl ethers (PBDEs), novel brominated flame retardants (NBFRs), dechlorane plus (DPs), and organophosphate flame retardants (PFRs), together with polychlorinated biphenyls (PCBs) were measured in indoor dust from five villages located in three e-waste recycling regions in Guangdong Province, South China. The medians of PBDEs, NBFRs, and PFRs in dust in five sites ranged from 685-67,500, 1460-50,010, and 2180-29,000ng/g, respectively. These concentrations were much higher than the medians of PCBs (52-2900ng/g). BDE 209 and decabromodiphenyl ethane (DBDPE) were the two major halogen flame retardants in dust, while tris-(1-chloro-2-propyl) phosphate (TCIPP) and triphenyl phosphate (TPHP) were the major PFRs. Principle component analysis revealed the different pollutant patterns among different sites. The estimated median human exposures of PBDEs, NBFRs, PFRs, and PCBs via dust ingestion were 1.1-24.1, 0.73-20.3, 1.36-23.5, and 0.04-0.93ng/kgbw/day for adults, and 16.2-352, 10.7-296, 19.9-343, 0.05-0.61, 0.65-13.6ng/kgbw/day for toddlers, respectively. Residents from Site 5 had the highest exposure (95 percentile levels and high dust ingestion for toddlers) of PBDEs (3920ng/kgbw/day), NBFRs (3200ng/kgbw/day), and PFRs (5280ng/kgbw/day). More attention should be paid to the contamination with NBFRs and PFRs, instead of PCBs, in these e-waste recycling regions, and local public health threat from PBDE alternatives should remain of concern. To the best of our knowledge, this is the first study on human exposure assessment of PFRs at e-waste sites.

  5. Steel dust in the New York City subway system as a source of manganese, chromium, and iron exposures for transit workers.

    Science.gov (United States)

    Chillrud, Steven N; Grass, David; Ross, James M; Coulibaly, Drissa; Slavkovich, Vesna; Epstein, David; Sax, Sonja N; Pederson, Dee; Johnson, David; Spengler, John D; Kinney, Patrick L; Simpson, H James; Brandt-Rauf, Paul

    2005-03-01

    The United States Clean Air Act Amendments of 1990 reflected increasing concern about potential effects of low-level airborne metal exposure on a wide array of illnesses. Here we summarize results demonstrating that the New York City (NYC) subway system provides an important microenvironment for metal exposures for NYC commuters and subway workers and also describe an ongoing pilot study of NYC transit workers' exposure to steel dust. Results from the TEACH (Toxic Exposure Assessment, a Columbia and Harvard) study in 1999 of 41 high-school students strongly suggest that elevated levels of iron, manganese, and chromium in personal air samples were due to exposure to steel dust in the NYC subway. Airborne concentrations of these three metals associated with fine particulate matter were observed to be more than 100 times greater in the subway environment than in home indoor or outdoor settings in NYC. While there are currently no known health effects at the airborne levels observed in the subway system, the primary aim of the ongoing pilot study is to ascertain whether the levels of these metals in the subway air affect concentrations of these metals or related metabolites in the blood or urine of exposed transit workers, who due to their job activities could plausibly have appreciably higher exposures than typical commuters. The study design involves recruitment of 40 transit workers representing a large range in expected exposures to steel dust, the collection of personal air samples of fine particulate matter, and the collection of blood and urine samples from each monitored transit worker.

  6. An assessment of polybrominated diphenyl ethers and polychlorinated biphenyls in the indoor dust of e-waste recycling facilities in South Africa: implications for occupational exposure.

    Science.gov (United States)

    Abafe, Ovokeroye A; Martincigh, Bice S

    2015-09-01

    Workplace exposure to persistent organic pollutants is a concern for human health. This study examined the presence of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in the indoor dust from two major e-waste recycling sites and a university electronic equipment repair workshop in Durban, South Africa, in order to evaluate the implication of dust for occupational exposure. The mean ∑(n = 8)PBDEs and ∑(n = 3)PCBs were 20,094 and 235 ng g(-1), respectively. The levels of PBDEs and PCBs obtained in one of the recycling sites (123-27,530 and 161-593 ng g(-1)) were significantly higher than the levels obtained (91-7686 and e-waste facilities are cleaned thoroughly regularly.

  7. Lung dust analysis in the assessment of past exposure of man-made mineral fibre workers.

    Science.gov (United States)

    McDonald, J C; Case, B W; Enterline, P E; Henderson, V; McDonald, A D; Plourde, M; Sébastien, P

    1990-10-01

    In the cohort of American MMMF workers reported by ENTERLINE et al. [Ann. occup. Hyg. 31, 625-656 (1987)] autopsies were recorded in 652 (13.5%) of 4840 deaths. Lung tissue samples were sought from all pathologists and obtained in 145 (22.2%), together with similar samples from 124 matched referents. Lung fibre counts by phase contrast microscopy were 60% higher (P less than 0.05) in workers than referents. Electron microscopy (ATEM) also showed more fibres of all kinds--MMMF, asbestos and other--but no convincing excess of any one type. Lung samples of only 26% of workers contained any MMMF, almost all siliceous in nature and in low concentration. There were too few cases of lung cancer (19) for any useful conclusion; however, in the plant with the highest lung cancer SMR (200), and a probable mesothelioma, amosite at greater than 1.0 fibres per micrograms (f micrograms-1) was found in four of six workers but in none of their matched referents. Although our findings contribute little to the interpretation of the results obtained by ENTERLINE et al. they indicate the potential value of tissue analyses in monitoring epidemiological studies of MMMF exposure.

  8. Respiratory symptoms and cross-shift lung function in relation to cotton dust and endotoxin exposure in textile workers in Nepal: a cross-sectional study

    OpenAIRE

    Paudyal, Priyamvada; Semple, SEAN; Gairhe, Santosh; Steiner, Markus F C; Niven, Rob; Jon G. Ayres

    2015-01-01

    Objectives: Inhalation of a cotton-based particulates has previously been associated with respiratory symptoms and impaired lung function. This study investigates the respiratory health of Nepalese textile workers in relation to dust and endotoxin exposure. Methods: A total of 938 individuals from four sectors (garment, carpet, weaving and recycling) of the textile industry in Kathmandu, Nepal completed a health questionnaire and performed spirometry. A subset (n=384) performed cross-shift sp...

  9. Assessment on the occupational exposure of urban public bus drivers to bioaccessible trace metals through resuspended fraction of settled bus dust

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Peng [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, No. 73 Huanghe Road, Nangang District, Harbin 150090 (China); Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA 01003 (United States); Liu, Sa [Environmental Health Sciences Division, School of Public Health, University of California, Berkeley, CA, 94720-7360 (United States); Ye, Wenyuan [Department of Chemical Engineering, KU Leuven, Willem de Croylaan 46, B-3001 Heverlee (Belgium); Lin, Nan; Meng, Ping [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, No. 73 Huanghe Road, Nangang District, Harbin 150090 (China); Feng, Yujie, E-mail: yujief@hit.edu.cn [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, No. 73 Huanghe Road, Nangang District, Harbin 150090 (China); Zhang, Zhaohan; Cui, Fuyi; Lu, Binyu [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, No. 73 Huanghe Road, Nangang District, Harbin 150090 (China); Xing, Baoshan [Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA 01003 (United States)

    2015-03-01

    Limited information is available on the bioaccessible fraction of trace metals in the resuspended fraction of settled bus dust in order to estimate bus drivers ' occupational exposure. In this study, 45 resuspended fraction of settled dust samples were collected from gasoline and compressed natural gas (CNG) powered buses and analyzed for trace metals and their fraction concentrations using a three-step sequential extraction procedure. Experimental results showed that zinc (Zn) had the greatest bioaccessible fraction, recorded as an average of 608.53 mg/kg, followed in order of decreasing concentration by 129.80 mg/kg lead (Pb), 56.77 mg/kg copper (Cu), 34.03 mg/kg chromium (Cr), 22.05 mg/kg nickel (Ni), 13.17 mg/kg arsenic (As) and 2.77 mg/kg cadmium (Cd). Among the three settled bus dust exposure pathways, ingestion was the main route. Total exposure hazard index (HIt) for non-carcinogenic effect trace metals was lower than the safety level of 1. The incremental lifetime cancer risk (ILCR) for drivers was estimated for trace metal exposure. Pb and Ni presented relatively high potential risks in the non-carcinogenic and potentially carcinogenic health assessment for all drivers. ILCR was in the range of 1.84E − 05 to 7.37E − 05 and 1.74E − 05 to 6.95E − 05 for gasoline and CNG buses, respectively. - Highlights: • As, Cd and Ni had relatively higher bioaccessibility and mobility in the resuspended fraction of settled bus dust. • Bioaccessible metal concentrations were higher in gasoline-fueled buses than those in CNG-fueled buses. • The carcinogenic risk probabilities to drivers were around the acceptable level.

  10. Chloride ingress in cement paste and mortar

    DEFF Research Database (Denmark)

    Jensen, Ole Mejlhede; Hansen, Per Freiesleben; Coats, Alison M.

    1999-01-01

    In this paper chloride ingress in cement paste and mortar is followed by electron probe microanalysis. The influence of several paste and exposure parameters on chloride ingress are examined (e.g., water-cement ratio, silica fume addition, exposure time, and temperature), The measurements...

  11. Historical exposure levels of inhalable dust in the Polish rubber industry compared to levels in Western Europe

    Energy Technology Data Exchange (ETDEWEB)

    Vocht, F de [Occupational and Environmental Health Research Group, School of Translational Medicine, Faculty of Medical and Human Sciences, The University of Manchester, Manchester (United Kingdom); Kromhout, H [Division of Environmental Epidemiology, Institute for Risk Assessment Sciences, Utrecht University, Utrecht (Netherlands); Sobala, W; Peplonska, B, E-mail: Frank.devocht@manchester.ac.u [Department of Occupational and Environmental Epidemiology, NOFER Institute of Occupational Medicine, Lodz (Poland)

    2009-02-01

    Although studies have been carried out to assess inhalable dust exposure levels in the rubber manufacturing industry, the levels of exposure in factories in Eastern Europe are less well documented. Routine stationary sampling for compliance testing of inhalable aerosols has however been conducted in a large factory producing tires and tubes in Poland between 1981 and 1996 (N=6,152). This study was conducted to assess historical inhalable aerosol levels in different departments in this rubber plant and to compare the results with estimates based on European data from the UK, Sweden, the Netherlands and Germany, and also Poland (EXASRUB project). Geometric mean (GM) concentrations in the factory ranged from 2.41 mg/m{sup 3} to 5.82 mg/m{sup 3} and were to a large extent associated to the actual production capacity of the plant and flow of the production process. Whereas 3-4 fold differences between departments existed prior to about 1985, stronger reduction of exposure in the raw materials and finishing departments (-12%/year) compared to other departments (range -5%/yr to -3%/yr), resulted in comparable levels in the 1990s. However, in the pre-treating departments, average concentrations were still about a factor 2-3 higher than in other departments, which could presumably be attributed to the use of anti-tacking agents. GM concentrations have been modelled using (1) stationary measurements collected in the Polish factory only, or (2) all European data collected in the EXASRUB project. Comparison of the estimates showed that these were fairly similar for both datasets. This analysis showed that the levels of inhalable aerosols in the Polish rubber industry have been at least a factor three to four higher than in Western European countries in the 1980s and 1990s, depending on the department, but that these differences were getting smaller in the 1990s. Furthermore, the estimates based on all European data from EXASRUB provides valid estimates compared to factory

  12. Metal Exposure and Associated Health Risk to Human Beings by Street Dust in a Heavily Industrialized City of Hunan Province, Central China

    Directory of Open Access Journals (Sweden)

    Guangyi Sun

    2017-03-01

    Full Text Available Fifty-five urban street dust samples were collected from Zhuzhou, an industrial city in central China and analyzed for a range of toxic elements. Potential carcinogenic and non-carcinogenic health effects on children and adults due to exposure to street dust were assessed. Concerning the two subgroups, the child cohort is confronted with considerably greater health risks than adults. According to the Hazard Quotient (HQ method, ingestion of dust particles poses primary risk to children and adults, followed by dermal contact and inhalation for all of the metals investigated except Hg, for which inhalation of its elemental vapor constitute a slightly higher risk than ingestion. For children, Pb, As, Cd, Cr, Hg and Sb exposure were deemed as the highest contributors to non-cancer health risks, while As and Cr represent an enhanced cancer risk for children. For adults, risk indicator values for both cancer and non-cancer effects obtained were within the safety threshold. In a comparison with other locations within and outside mainland China, exposure to arsenic is prominent for the population of Zhuzhou, indicating more attention and preventive actions should been taken.

  13. Effect of hydrogen sulfide emissions on cement mortar specimens

    Energy Technology Data Exchange (ETDEWEB)

    Idriss, A. F. [Alberta Environment, Science and Technology Branch, Edmonton, AB (Canada); Negi, S. C.; Jofriet, J. C.; Haywoard, G. L. [Guelph Univ., Guelph, ON (Canada)

    2001-07-01

    Six different cement mortar specimens used in animal buildings, where they were exposed to hydrogen sulfide generated from anaerobic fermentation of manure during a period of one year, were investigated. Primary interest was on comparing the corrosion resistance of different cement mortar specimens under long term exposure to hydrogen sulfide. The impressed voltage technique was used to test the specimens in the laboratory. Results revealed that test specimens made with eight per cent silica fume cement replacement performed best and similar Portland cement mortar specimens with a water-cement ratio of 0.55 (PC55) the poorest. All other treatments, (Portland cement with a water to cement ratio of 045, Portland cement Type 50, Portland cement with fibre mesh and Portland cement Type 10 coated with linseed oil) all with water-cement ratios of 0.45, were less effective in preventing corrosion than silica fume replacement.

  14. Cancer mortality and wood dust exposure among participants in the American Cancer Society Cancer Prevention Study-II (CPS-II).

    Science.gov (United States)

    Stellman, S D; Demers, P A; Colin, D; Boffetta, P

    1998-09-01

    In 1994, the International Agency for Research on Cancer (IARC) classified wood duct as a human carcinogen, based on very strong evidence of a carcinogenic risk of sino-nasal cancer. Excesses of other cancers, including lung and stomach, have been reported among persons employed in wood industries or occupationally exposed to wood dust, but not as consistently. We investigated such possible associations using the mortality experience of 362,823 men enrolled in the American Cancer Society's Cancer Prevention Study-II in 1982 and followed up for 6 years. Within this group, 45,399 men (12.5%) reported either employment in a wood-related occupation or exposure to wood dust or both. Among woodworkers, a small but significant excess risk was found for all cases of death (RR 1.17 (95% CI 1.11-1.24)) and for total malignancies (RR 1.17 (1.05-1.30)). Among men who reported exposure to wood dust, there was an elevated risk of total mortality (Rr 1.07 (1.03-1.11)), total malignancies (RR 1.08 (1.01-1.15)), and lung cancer (RR 1.17 (1.04-1.31)). Among woodworkers, a significant trend (P = 0.02) of increasing risk of lung cancer with increasing duration of exposure was observed. An unexpected, significantly increased mortality from prostate cancer was observed in both wood-employed and wood-exposed, and a twofold increased risk of fatal brain cancer was seen among the former. Lung cancer mortality was especially high among woodworkers who also reported exposure to asbestos or formaldehyde, and it appears that exposure to these known carcinogens may partly explain the observed increased risks. Excess sino-nasal cancer was not observed, but the number of cases was small.

  15. Investigation and control measures of occupational hazards in grinding station of a cement enterprise of Aoxi%奥西某水泥公司粉磨站职业病危害调查及控制措施

    Institute of Scientific and Technical Information of China (English)

    卢建国; 朱春兰; 陈枨光

    2013-01-01

    目的 调查奥西某水泥公司水泥粉磨站的工艺特点、职业病危害因素的种类及浓(强)度,提出相应的控制措施.方法 对水泥粉磨站的工艺流程、职业病危害因素种类及现场检测的资料进行收集、整理与分析.结果 该水泥粉磨站工艺特点为采用新技术设备.职业病危害因素主要是粉尘(水泥尘、矽尘、石灰石粉尘、石膏粉尘和熟料尘)和噪声2类.粉尘时间加权平均(TWA)浓度范围0.3~44.4 mg/m3,超标率53.3%;短时间接触浓度(STEL)范围0.3~68.0 mg/m3,超标率19.0%.水泥粉尘浓度超标38.9%~58.3%,熟料尘浓度超标11.1%~33.3%,矽尘、石灰石粉尘和石膏粉尘浓度均在国家职业卫生限值范围内.作业岗位的个体噪声强度为78.9~ 86.4 dB(A),超标率为16.7%.结论 该项目职业病危害因素为水泥粉尘、熟料粉尘和噪声.对此提出了职业病危害预防控制措施和管理措施,以保护劳动者身体健康.%[Objective]To investigate the process characteristics, species and exposure levels of occupational hazards in grinding station of a cement enterprise of Aoxi, and put forward related control measures. [ Methods] The production process, species of occupational hazards and field detection data in the cement grinding station were collected and analyzed. [Results] The cement grinding station technology was characterized by adopting new technology and equipment. Noise and dust (cement dust, silica dust, limestone dust, gypsum dust and clinker dust) were primary occupational hazards. Dust TWA ranged from 0.3-44.4 mg/m3, with over standard rate of 53.3% ; The STEL ranged from 0.3-68.0 mg/m3, with over standard rate of 19.0%. Cement dust concentrations exceeded the standard from 38.9%-58. 3% ; clinker dust concentrations exceeded the standard from 11. 1%-33. 3% ; silica dust, limestone dust and plaster dust concentration were within the national occupation health limits. The individual noise

  16. Characterization of heavy metals and brominated flame retardants in the indoor and outdoor dust of e-waste workshops: implication for on-site human exposure.

    Science.gov (United States)

    Xu, Feng; Liu, Yangcheng; Wang, Junxia; Zhang, Gang; Zhang, Wei; Liu, Lili; Wang, Jinfu; Pan, Bishu; Lin, Kuangfei

    2015-04-01

    Forty-four indoor and outdoor dust samples were collected from e-waste workshops and were analyzed to characterize the heavy metals and brominated flame retardants (BFRs) as well as on-site human exposure. The results showed that the most abundant Polybrominated diphenyl ethers (PBDE) congener from three sites was deca-BDE, and it was penta-BDE for the other site. A significant and positive association was found between BDE-209 and decabromodiphenyl ethane (DBDPE). The high percentage of nona-BDE indicated the debromination of deca-BDE during e-waste recycling. The ratio comparison of BDE-47 to (BDE-100 + BDE-99) indicated that the outdoor dust went through more physiochemical processes. The enrichment factors for Cu and Pb were high in both the indoor and outdoor samples. Cd significantly exceeded the Chinese soil guideline grade III. The PCA results combined with the enrichment factor (EF) values suggested common sources and behaviours of Cu, Pb and Sb in the indoor dust. Co, Cr, Ni, Zn and Mn in the outdoor samples were more likely affected by crust. Strong correlations were found only for Pb and Sb with polybrominated diphenyl ethers (PBDEs). The hazard index for on-site human exposure to Pb was at a chronic risk. Despite the low deleterious risk of BFRs, concern should be given to DBDPE; the chronic toxicity of which is not known.

  17. Biomonitoring of Air Pollution by Magnetic Measurements of Native and Transplanted Lichens; Two Case Studies Around Cement Plants

    Science.gov (United States)

    Winkler, A.; Paoli, L.; Kodnik, D.; Candotto Carniel, F.; Guttová, A.; Loppi, S.; Sagnotti, L.; Tretiach, M.

    2015-12-01

    A cement plant is a source of dust pollution and lichens are suitable biomonitors of the impact of airborne pollutants released during cement production. We investigated the magnetic and chemical properties of lichens exposed around two cement plants, located in SW Slovakia and in NE Italy, respectively. We characterized the magnetic properties of the lichen Evernia prunastri exposed for 180 days at selected sites around a Slovak cement plant in order to define the magnetic mineralogy and test the correlations between the concentration-dependent magnetic parameters and the content of heavy metals and crustal elements in the thalli. In addition, we compared the magnetic properties of the transplants to those carried by native thalli of the lichen Xanthoria parietina and neighboring soils, barks and rocks. The data indicated a substantial homogenous magnetic mineralogy, with the exception of a sample collected from a basalt quarry. The transplants showed an excellent correlation between the saturation remanent magnetization (Mrs) and the concentration of Fe; the concentrations of the elements linked to cement production also correlated to Mrs values, apart from the basalt quarry sample. In the second context, we characterized the magnetic properties of the lichen Pseudevernia furfuracea transplanted near a cement plant in NE Italy. The transplants were exposed for 2 months in 40 sites distributed in surrounding rural, urban and industrial areas. In this case, the agreement between the magnetic and elemental datasets pointed out a modest environmental impact of the cement plant compared to the neighboring industrial activities, which resulted in significantly higher values of the concentration-dependent magnetic parameters. Magnetic analyses on lichens can expand the dataset of passive dust collectors in environmental magnetism, with the advantage, for the transplants, of precisely knowing the exposure time and the initial conditions.

  18. Influence of the temperature on the cement disintegration in cement-retained implant restorations.

    Science.gov (United States)

    Linkevicius, Tomas; Vindasiute, Egle; Puisys, Algirdas; Linkeviciene, Laura; Svediene, Olga

    2012-01-01

    The aim of this study was to estimate the average disintegration temperature of three dental cements used for the cementation of the implant-supported prostheses. One hundred and twenty metal frameworks were fabricated and cemented on the prosthetic abutments with different dental cements. After heat treatment in the dental furnace, the samples were set for the separation to test the integration of the cement. Results have shown that resin-modified glass-ionomer cement (RGIC) exhibited the lowest disintegration temperature (pcement (ZPC) and dual cure resin cement (RC) (p>0.05). Average separation temperatures: RGIC - 306 ± 23 °C, RC - 363 ± 71 °C, it could not be calculated for the ZPC due to the eight unseparated specimens. Within the limitations of the study, it could be concluded that RGIC cement disintegrates at the lowest temperature and ZPC is not prone to break down after exposure to temperature.

  19. Correlation of in vivo relative bioavailability to in vitro bioaccessibility for arsenic in household dust from China and its implication for human exposure assessment.

    Science.gov (United States)

    Li, Hong-Bo; Li, Jie; Juhasz, Albert L; Ma, Lena Q

    2014-12-01

    Incidental ingestion of household dust is an important arsenic (As) exposure pathway for children. However, compared to soils, assessment of As relative bioavailability (RBA) in household dust is limited. In this study, As-RBA in 12 household dust samples (7–38 mg kg(–1)) was measured using an in vivo mouse model and compared to As bioaccessibility determined using 4 assays [Solubility Bioaccessibility Research Consortium method (SBRC), in vitro gastrointestinal method (IVG), Deutsches Institut für Normunge.V. method (DIN), and physiologically based extraction test (PBET)]. Arsenic RBA ranged from 21.8 ± 1.6 to 85.6 ± 7.2% with samples containing low Fe and high total organic carbon content having higher As-RBA. Strong in vivo–in vitro correlations (IVIVC) were found between As-RBA and As bioaccessibility for SBRC and DIN (r2 = 0.63–0.85), but weaker ones were obtained for IVG and PBET (r2 = 0.29–0.55). The developed IVIVC for SBRC and DIN were used to calculate As-RBA based on As bioaccessibility for an additional 12 household dust samples. Although As bioaccessibility differed significantly (up to 7.7-fold) based on in vitro methods, predicted As-RBA was less variable (up to 3.0-fold) when calculated using As bioaccessibility data and the corresponding IVIVC. Our data suggested that both SBRC and DIN had potential to assess As bioavailability in household dust samples; however, additional research is needed.

  20. Evaluation of the fate and pathological response in the lung and pleura of brake dust alone and in combination with added chrysotile compared to crocidolite asbestos following short-term inhalation exposure

    Energy Technology Data Exchange (ETDEWEB)

    Bernstein, D.M., E-mail: davidb@itox.ch [Consultant in Toxicology, Geneva (Switzerland); Rogers, R.A., E-mail: rarogers5@yahoo.com [Rogers Imaging, Needham, MA (United States); Sepulveda, R. [Rogers Imaging, Needham, MA (United States); Kunzendorf, P., E-mail: Peter.Kunzendorf@GSA-Ratingen.de [GSA Gesellschaft für Schadstoffanalytik mbH, Ratingen (Germany); Bellmann, B. [Fraunhofer Institute for Toxicology and Experimental Medicine, Hannover (Germany); Ernst, H., E-mail: Heinrich.ernst@item.fraunhofer.de [Fraunhofer Institute for Toxicology and Experimental Medicine, Hannover (Germany); Creutzenberg, O. [Fraunhofer Institute for Toxicology and Experimental Medicine, Hannover (Germany); Phillips, J.I., E-mail: jim.phillips@nioh.nhls.ac.za [National Institute for Occupational Health, National Health Laboratory Service, Johannesburg South Africa and Department of Biomedical Technology, Faculty of Health Sciences, University of Johannesburg, Johannesburg (South Africa)

    2015-02-15

    This study was designed to provide an understanding of the biokinetics and potential toxicology in the lung and pleura following inhalation of brake dust following short term exposure in rats. The deposition, translocation and pathological response of brake-dust derived from brake pads manufactured with chrysotile were evaluated in comparison to the amphibole, crocidolite asbestos. Rats were exposed by inhalation 6 h/day for 5 days to either brake-dust obtained by sanding of brake-drums manufactured with chrysotile, a mixture of chrysotile and the brake-dust or crocidolite asbestos. The chrysotile fibers were relatively biosoluble whereas the crocidolite asbestos fibers persisted through the life-time of the animal. This was reflected in the lung and the pleura where no significant pathological response was observed at any time point in the brake dust or chrysotile/brake dust exposure groups through 365 days post exposure. In contrast, crocidolite asbestos produced a rapid inflammatory response in the lung parenchyma and the pleura, inducing a significant increase in fibrotic response in both of these compartments. Crocidolite fibers were observed embedded in the diaphragm with activated mesothelial cells immediately after cessation of exposure. While no chrysotile fibers were found in the mediastinal lymph nodes, crocidolite fibers of up to 35 μm were observed. These results provide support that brake-dust derived from chrysotile containing brake drums would not initiate a pathological response in the lung or the pleural cavity following short term inhalation. - Highlights: • Evaluated brake dust w/wo added chrysotile in comparison to crocidolite asbestos. • Persistence, translocation, pathological response in the lung and pleural cavity. • Chrysotile cleared rapidly from the lung while the crocidolite asbestos persisted. • No significant pathology in lung or pleural cavity observed at any time point in the brake-dust groups. • Crocidolite quickly

  1. Decreased mitochondrial DNA content in association with exposure to polycyclic aromatic hydrocarbons in house dust during wintertime: from a population enquiry to cell culture.

    Directory of Open Access Journals (Sweden)

    Nicky Pieters

    Full Text Available Polycyclic aromatic hydrocarbons (PAHs are widespread environmental pollutants that are formed in combustion processes. At the cellular level, exposure to PAHs causes oxidative stress and/or some of it congeners bind to DNA, which may interact with mitochondrial function. However, the influence of these pollutants on mitochondrial DNA (mtDNA content remains largely unknown. We determined whether indoor exposure to PAHs is associated with mitochondrial damage as represented by blood mtDNA content. Blood mtDNA content (ratio mitochondrial/nuclear DNA copy number was determined by real-time qPCR in 46 persons, both in winter and summer. Indoor PAH exposure was estimated by measuring PAHs in sedimented house dust, including 6 volatile PAHs and 8 non-volatile PAHs. Biomarkers of oxidative stress at the level of DNA and lipid peroxidation were measured. In addition to the epidemiologic enquiry, we exposed human TK6 cells during 24 h at various concentrations (range: 0 to 500 µM of benzo(apyrene and determined mtDNA content. Mean blood mtDNA content averaged (± SD 0.95 ± 0.185. The median PAH content amounted 554.1 ng/g dust (25(th-75(th percentile: 390.7-767.3 and 1385 ng/g dust (25(th-75(th percentile: 1000-1980 in winter for volatile and non-volatile PAHs respectively. Independent for gender, age, BMI and the consumption of grilled meat or fish, blood mtDNA content decreased by 9.85% (95% CI: -15.16 to -4.2; p = 0.002 for each doubling of non-volatile PAH content in the house dust in winter. The corresponding estimate for volatile PAHs was -7.3% (95% CI: -13.71 to -0.42; p = 0.04. Measurements of oxidative stress were not correlated with PAH exposure. During summer months no association was found between mtDNA content and PAH concentration. The ability of benzo(apyrene (range 0 µM to 500 µM to lower mtDNA content was confirmed in vitro in human TK6 cells. Based on these findings, mtDNA content can be a target of PAH toxicity in humans.

  2. Decreased mitochondrial DNA content in association with exposure to polycyclic aromatic hydrocarbons in house dust during wintertime: from a population enquiry to cell culture.

    Science.gov (United States)

    Pieters, Nicky; Koppen, Gudrun; Smeets, Karen; Napierska, Dorota; Plusquin, Michelle; De Prins, Sofie; Van De Weghe, Hendrik; Nelen, Vera; Cox, Bianca; Cuypers, Ann; Hoet, Peter; Schoeters, Greet; Nawrot, Tim S

    2013-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental pollutants that are formed in combustion processes. At the cellular level, exposure to PAHs causes oxidative stress and/or some of it congeners bind to DNA, which may interact with mitochondrial function. However, the influence of these pollutants on mitochondrial DNA (mtDNA) content remains largely unknown. We determined whether indoor exposure to PAHs is associated with mitochondrial damage as represented by blood mtDNA content. Blood mtDNA content (ratio mitochondrial/nuclear DNA copy number) was determined by real-time qPCR in 46 persons, both in winter and summer. Indoor PAH exposure was estimated by measuring PAHs in sedimented house dust, including 6 volatile PAHs and 8 non-volatile PAHs. Biomarkers of oxidative stress at the level of DNA and lipid peroxidation were measured. In addition to the epidemiologic enquiry, we exposed human TK6 cells during 24 h at various concentrations (range: 0 to 500 µM) of benzo(a)pyrene and determined mtDNA content. Mean blood mtDNA content averaged (± SD) 0.95 ± 0.185. The median PAH content amounted 554.1 ng/g dust (25(th)-75(th) percentile: 390.7-767.3) and 1385 ng/g dust (25(th)-75(th) percentile: 1000-1980) in winter for volatile and non-volatile PAHs respectively. Independent for gender, age, BMI and the consumption of grilled meat or fish, blood mtDNA content decreased by 9.85% (95% CI: -15.16 to -4.2; p = 0.002) for each doubling of non-volatile PAH content in the house dust in winter. The corresponding estimate for volatile PAHs was -7.3% (95% CI: -13.71 to -0.42; p = 0.04). Measurements of oxidative stress were not correlated with PAH exposure. During summer months no association was found between mtDNA content and PAH concentration. The ability of benzo(a)pyrene (range 0 µM to 500 µM) to lower mtDNA content was confirmed in vitro in human TK6 cells. Based on these findings, mtDNA content can be a target of PAH toxicity in humans.

  3. Effect of cement industry pollution on chlorophyll content of some crops at Kodinar, Gujarat, India

    OpenAIRE

    2013-01-01

    Study was carried out to assess the impact of cement industry pollution on some selected plant species around cement industry. Effect of cement dust on chlorophyll was studied in Arachis hypogaea, Sesamum indicum and Triticum species. Sampling was done at different distance like 0.5 km, 1.0 km and 2.0 km from the cement industry. The Chlorophyll pigments were reduced in dust-exposed plant species compared with control site Pransli (15 km away from the cement industry). Changes in chlorophyll ...

  4. Predicted risk of childhood allergy, asthma, and reported symptoms using measured phthalate exposure in dust and urine

    DEFF Research Database (Denmark)

    Hsu, N.-Y.; Lee, C.-C.; Wang, J.-Y.;

    2012-01-01

    The associated risk of phthalate exposure, both parent compounds in the home and their metabolites in urine, to childhood allergic and respiratory morbidity, after adjusting for exposures of indoor pollutants, especially bioaerosols, was comprehensively assessed. Levels of five phthalates...

  5. Organic contaminants and heavy metals in indoor dust from e-waste recycling, rural, and urban areas in South China: Spatial characteristics and implications for human exposure.

    Science.gov (United States)

    He, Chun-Tao; Zheng, Xiao-Bo; Yan, Xiao; Zheng, Jing; Wang, Mei-Huan; Tan, Xiao; Qiao, Lin; Chen, She-Jun; Yang, Zhong-Yi; Mai, Bi-Xian

    2017-02-27

    The concentrations of several organic contaminants (OCs) and heavy metals were measured in indoor dust from e-waste recycling, rural, and urban areas in South China to illustrate the spatial characteristics of these pollutants and to further evaluate human exposure risks. The median concentrations of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), decabromodiphenyl ethane (DBDPE), and dechlorane plus (DPs) were 38.6-3560, 2360-30,100, 665-2720, and 19.5-1860ng/g, while the median concentrations of Cd, Pb, Cu, Cr, and Zn were 2.46-40.4, 206-1380, 217- 1200, 25.3-134, and 176-212μg/g in indoor dust. The levels of all pollutants, except Zn, in dust from the e-waste recycling area were significantly higher than those from the other areas. Cd, Pb, and most OCs exhibited similar pollution patterns in the three areas, indicating that e-waste recycling activities are the major pollution source. In contrast, Cu, Cr, Zn, and penta-BDE are likely derived from household products in the rural and urban areas. The highest estimated daily intakes (EDIs) of PCBs, PBDEs, DBDPE, and DPs were 0.15-163, 3.97-1470, 1.26-169, and 0.11-134ng/kg bw/day for toddlers and adults. The highest EDIs of BDE 209 and Pb in toddlers in the e-waste recycling area were 16% and 18 times higher than the reference doses, indicating the high exposure risk of these pollutants in the e-waste recycling area.

  6. Some durability aspects of hybrid alkaline cements

    Directory of Open Access Journals (Sweden)

    Donatello S.

    2014-04-01

    Full Text Available Blended cements that contain a high content of fly ash and a low content of Portland cement typically suffer from low early strength development and long setting times. Recently, one method of overcoming these problems has been to use an alkali activator to enhance the reactivity of fly ash particles at early ages. Such cements can be grouped under the generic term “hybrid alkaline cements”, where both cement clinker and fly ash, encouraged by the presence of alkalis, are expected to contribute to cementitious gel formation. The work presented here examines some of the durability aspects of high fly ash content hybrid alkaline cement. Specifically, the aspects investigated were: exposure at high temperatures (up to 1000°C, resistance to immersion in aggressive solutions and susceptibility to the alkali aggregate reaction. All tests were repeated with a commercially available sulfate resistant Portland cement for comparison. When exposed to high temperatures, the hybrid alkaline cement showed strikingly different behaviour compared to the control Portland cement, showing fewer micro-cracks and maintaining residual compressive strengths at least equal to original strengths. Beyond 700°C, the hybrid alkaline cement began to sinter, which resulted in shrinkage of around 5% and a 100% increase in residual compressive strengths. No such sintering event was noted in the control Portland cement, which showed a drastic loss in residual compressive strengths upon heating. In immersion tests, the hybrid alkaline cement possessed excellent resistance to sulfate and seawater attack, similar to the control sulfate resistant cement. Both cements were however severely degraded by immersion in 0.1M HCl for 90 days. Both binders complied with the accelerated alkali-aggregate test but when this test was extended, the hybrid alkaline binder showed much greater dimensional stability. Possible reasons for the differences in durability behaviour in both cements

  7. Quartz and respirable dust in the Dutch construction industry: A baseline exposure assessment as part of a multidimensional intervention approach

    NARCIS (Netherlands)

    Deurssen, E. van; Pronk, A.; Spaan, S.; Goede, H.; Tielemans, E.; Heederik, D.; Meijster, T.

    2014-01-01

    Quartz exposure can cause several respiratory health effects. Although quartz exposure has been described in several observational workplace studies, well-designed intervention studies that investigate the effect of control strategies are lacking. Tis article describes a baseline exposure study that

  8. CEMENT SLURRIES FOR GEOTHERMAL WELLS CEMENTING

    Directory of Open Access Journals (Sweden)

    Nediljka Gaurina-Međimurec

    1994-12-01

    Full Text Available During a well cementing special place belongs to the cement slurry design. To ensure the best quality of cementing, a thorough understanding of well parameters is essential, as well as behaviour of cement slurry (especially at high temperatures and application of proven cementing techniques. Many cement jobs fail because of bad job planning. Well cementing without regarding what should be accomplished, can lead to well problems (channels in the cement, unwanted water, gas or fluid production, pipe corrosion and expensive well repairs. Cementing temperature conditions are important because bot-tomhole circulating temperatures affect slurry thickening time, arheology, set time and compressive strength development. Knowing the actual temperature which cement encounters during placement allows the selection of proper cementing materials for a specific application. Slurry design is affected by well depth, bottom hole circulating temperature and static temperature, type or drilling fluid, slurry density, pumping time, quality of mix water, fluid loss control, flow regime, settling and free water, quality of cement, dry or liquid additives, strength development, and quality of the lab cement testing and equipment. Most Portland cements and Class J cement have shown suitable performances in geot-hermal wells. Cement system designs for geothermal wells differ from those for conventional high temperature oil and gas wells in the exclusive use of silica flour instead of silica sand, and the avoidance of fly ash as an extender. In this paper, Portland cement behaviour at high temperatures is described. Cement slurry and set cement properties are also described. Published in literature, the composition of cement slurries which were tested in geothermal conditions and which obtained required compressive strength and water permeability are listed. As a case of our practice geothermal wells Velika Ciglena-1 and Velika Ciglena-la are described.

  9. [Evaluation of long-term occupational exposure to dust and its effect on health during production of ceramic tiles].

    Science.gov (United States)

    Gielec, L; Izycki, J; Woźniak, H

    1992-01-01

    A medical examination has been carried out of 500 workers (290 men and 210 women) of a ceramic plates plant. Also, the measurements of dust concentrations were made at some standard work places . In the materials used for manufacturing the plates crystalline phases and the content of free crystalline silica were determined using the X-ray diffraction method. In the animal experiments the fibrogenic activity of all materials used in the plant was examined and compared to the fibrogenic activity of standard quartz. As a result of the medical examination 64 cases of pneumoconiosis were diagnosed (13% of the subjects). The incidence rate of pneumoconiosis was similar for men and women. The radiological changes characteristic of pneumoconiosis took approximately 24 years of the workers tenure to develop. Type q changes were most frequent (69%), types p and r were observed in 14% of workers (mostly women). In 31% of workers tuberous changes of size B were observed. In 43.8% of the subjects restrictive disorders of ventilation were found. In 30% of workers chronic bronchitis was diagnosed. Dust concentrations at 11 work places were measured using the individual dosimetry method. Total dust concentrations ranged from 0.6 mg/m3 at the electricians posts to 60.1 mg/m3 at the workposts where the furnace truck restorers worked. Dust concentrations exceeded the MACs at 7 workposts. The respirable fraction concentrations ranged from 0.1 mg/m3 to 8.4 mg/m3. During the replacement of asbestos ropes and asbestos board used for insulating the furnace trucks mineral fibres (0.1-0.5 fibre/cm3) were found in the air. The following crystalline phases were determined in the materials: kaolinite, illite, quartz, orthoclase and microline.(ABSTRACT TRUNCATED AT 250 WORDS)

  10. Undisturbed dust as a metric of long-term indoor insecticide exposure: Residential DDT contamination from indoor residual spraying and its association with serum levels in the VHEMBE cohort.

    Science.gov (United States)

    Gaspar, Fraser W; Chevrier, Jonathan; Bornman, Riana; Crause, Madelein; Obida, Muvhulawa; Barr, Dana Boyd; Bradman, Asa; Bouwman, Henk; Eskenazi, Brenda

    2015-12-01

    Although approximately 123 million people may be exposed to high levels of insecticides through the use of indoor residual spraying (IRS) for malaria control, few studies exist on indoor insecticide contamination due to IRS and its relationship with human exposure. In the present study, we developed a sampling method to collect undisturbed dust from 50 homes in Limpopo, South Africa, a region where dichlorodiphenyltrichloroethane (DDT) has been used in IRS programs to prevent malaria for ~70years. We quantified DDT and its degradation products, dichlorodiphenyldichloroethylene (DDE), and dichlorodiphenyldichloroethane (DDD) in dust samples to determine dust loading levels and compared these levels to paired serum concentrations of p,p'-DDT and p,p'-DDE in women residents. p,p'-DDT and p,p'-DDE had the highest detection frequencies in both dust (58% and 34% detection, respectively) and serum samples (98% and 100% detection, respectively). Significantly higher detection frequencies for o,p'-DDT, p,p'-DDE, and p,p'-DDD were observed in dust samples collected in buildings that had been previously sprayed for malaria control. We also observed a significant, positive association between dust loading and serum concentrations of p,p'-DDT and p,p'-DDE (Spearman's rho=0.68 and 0.54, respectively). Despite the low detection frequency in dust, our results indicate that undisturbed dust may be a good metric to quantify long-term home exposure to DDT-related compounds and that contamination of the home environment may be an important determinant/source of DDT and DDE exposure.

  11. PCB-containing wood floor finish is a likely source of elevated PCBs in residents' blood, household air and dust: a case study of exposure

    Directory of Open Access Journals (Sweden)

    Seryak Liesel M

    2008-01-01

    Full Text Available Abstract Background Polychlorinated biphenyls (PCBs are persistent pollutants identified worldwide as human blood and breast milk contaminants. Because they bioaccumulate, consumption of meat, fish, and dairy products predicts human blood concentrations. PCBs were also used widely in building materials, including caulks and paints, but few studies have evaluated the contribution of these exposures to body burden. Methods In an earlier study, we detected PCBs in indoor air in 31% of 120 homes on Cape Cod, MA. Two of the homes had much higher concentrations than the rest, so we retested to verify the initial finding, evaluate blood PCB concentrations of residents, and identify the PCB source. Results Air and dust concentrations remained elevated over 5 years between initial and follow-up sampling. Blood serum concentrations of PCBs in residents of the homes were generally elevated above the 95th percentile of a representative sample of the US population. Serum concentrations in residents and air and dust concentrations were especially high in a home where a resident reported use of PCB-containing floor finish in the past, and where the floor of one room was sanded and refinished just prior to sample collection. Conclusion This case-study suggests that PCB residues in homes may be more significant contributors to overall exposure than diet for some people, and that use of a commercially-available PCB-containing wood floor finish in residences during the 1950s and 1960s is an overlooked but potentially important source of current PCB exposure in the general population.

  12. PBDEs Levels in House Dust and Human Exposure to PBDEs via Dust Ingestion in Hangzhou%杭州城区室内灰尘中多溴联苯醚的含量及人体暴露水平

    Institute of Scientific and Technical Information of China (English)

    金漫彤; 滕丹丹; 郑艳霞; 胡张璇; 沈学优; 金赞芳

    2016-01-01

    为了评估杭州城区室内灰尘中多溴联苯醚(PBDEs)污染程度,2013年3~8月,在杭州城区随机采集19个办公室、家庭和学生宿舍的室内灰尘样品.用 GC-ECD 定量分析了样品中14种 PBDEs 同系物的含量水平、同系物分布和可能的影响因素,并估算了成年人和儿童通过灰尘摄入对 PBDEs 的暴露水平.结果表明,办公室∑14 PBDEs 的平均值9.28×102 ng•g -1,中值为1.03×103 ng•g -1;家庭∑14 PBDEs 的平均值7.83×102 ng•g -1,中值为9.11×102 ng•g -1;学生宿舍∑14 PBDEs 的平均值4.07×102 ng•g -1,中值为4.03×102 ng•g -1,办公室的污染水平高于居住环境. BDE-209是贡献值最大的单体,其贡献值为75.48%,其次分别是 BDE-190、 BDE-154和 BDE-71.成年人和儿童通过灰尘摄入的 PBDEs 暴露水平分别为13.12~32.63 ng•d -1和32.40~54.54 ng•d -1,灰尘中儿童的 PBDEs 人体暴露量高于成人的人体暴露量,主要是因为儿童灰尘摄入量要高于成人.分析得出,从室内灰尘摄入的 PBDEs 存在健康隐患,儿童潜在危害最大.%In order to evaluate the pollution degree of the dust in Hangzhou City, the indoor dust samples of 19 offices, families and students’ dormitories were collected from August to March in 2013 at Hangzhou for evaluating the pollution level of polybrominated diphenyl ethers ( PBDEs), to analyze concentrations of 14 PBDEs congeners and congener distribution as well as the possible influencing factors, and to estimate the PBDEs exposure levels of adults and children through the dust intake. The results showed that the average ∑14 PBDEs of office was 9. 28 × 102 ng•g - 1 , and the median was 1. 03 × 103 ng•g - 1; the average ∑14 PBDEs of family was 7. 83 × 102 ng•g - 1 , and the median was 9. 11 × 102 ng•g - 1; the average ∑14 PBDEs of student dormitory was 4. 07 × 102 ng•g - 1 , and the median was 4. 03 × 102 ng•g - 1 . The pollution level of the office was higher

  13. Lunar cement

    Science.gov (United States)

    Agosto, William N.

    1992-01-01

    With the exception of water, the major oxide constituents of terrestrial cements are present at all nine lunar sites from which samples have been returned. However, with the exception of relatively rare cristobalite, the lunar oxides are not present as individual phases but are combined in silicates and in mixed oxides. Lime (CaO) is most abundant on the Moon in the plagioclase (CaAl2Si2O8) of highland anorthosites. It may be possible to enrich the lime content of anorthite to levels like those of Portland cement by pyrolyzing it with lunar-derived phosphate. The phosphate consumed in such a reaction can be regenerated by reacting the phosphorus product with lunar augite pyroxenes at elevated temperatures. Other possible sources of lunar phosphate and other oxides are discussed.

  14. Pollution and Prevention of Pb during Cement Calcination

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Emission pollution and prevention measures of Pb during cement calcination were discussed. The content of Pb and the variation of composition were explored by means of atomic absorption spectroscopy (AAS) and X-ray diffraction. The results show that a number of Pb emits during cement calcination, F and C1 promote the emission of Pb, and Pb is enriched in kiln dust. The smaller the particle of kiln dust, the higher the content of Pb. When utilizing the raw materials with a high content of Pb, a more efficient dust collector should be used and the kiln dust should be used as the addition of cement. Pb in clinker is enriched in the intermediate phase. The reduction of silica modulus is useful to increase the solidification content of Pb in clinker. The solidification content of Pb in calcium sulphoaluminate mineral is higher than that in calcium aluminate mineral.

  15. Assessment of violations of the proteomic profile in blood plasma in children being under inhalation exposure to fine dust containing vanadium

    Directory of Open Access Journals (Sweden)

    N.V. Zaitseva

    2016-03-01

    Full Text Available The results of research and evaluation of the protein profile in blood plasma in children, that have been exposed to long-term effect of fine dust containing vanadium in the zone of influence of metallurgical production sources, are demonstrated. It was established that under conditions of poor air quality in the residential area due to vanadium pentoxide dust content at the level up to 1.2 mean daily MAC (34 RfC chr , by the suspended solids – up to 0.6 mean daily MAC (1.2 RfC chr , there is vanadium concentration in blood of the exposed 4–7 aged children, that exceeds up to 6 times the reference level. The technology of the proteomic analysis showed that children with high content of vanadium in blood have changes in proteomic profile in blood plasma in the type of increase of the relative volume of acid glycoprotein alpha-1; reduction of clusterin, apolipoprotein A-IV, alpha-2-HS-glycoprotein, that are associated with vanadium concentration in blood. In the absence of timely primary and secondary prevention and the preservation of vanadium sustained exposure the revealed cell-molecular abnormalities allow us to predict further development of functional disturbances on tissue and organ levels as the early development of osteoporosis and osteoarticular pathology, atherosclerotic vascular changes, autoimmune allergic processes on the background of disorders of immune regulation, oncology diseases.

  16. Increased ventilation rate as way to reduce the exposure to house dust mites and improve the health of asthmatic children - an intervention design

    DEFF Research Database (Denmark)

    Spilak, Michal; Kolarik, Barbara; Gunnarsen, Lars

    2012-01-01

    International field studies have documented that indoor air quality is unsatisfactory in many buildings. The overall hypothesis of this project is that improving the indoor environment in dwellings can improve health and reduce suffering from indoor related diseases such as allergy and asthma...... that have shown a marked increase in incidence all around the world during last decades. The purpose of this study is to investigate the effect of increased ventilation and expected lower exposure to house dust mites on symptoms and medication intake among asthmatic children. This will be done by installing...... balanced mechanical ventilation systems in 80 single-family houses. Half of the houses will be equipped with an effective ventilation system increasing air change rates from normal to approximately 3 h-1. A fake ventilation system will be installed in the other half of the houses. Primary subjects...

  17. Comparing South African occupational exposure limits for pesticides, metals, dusts and fibres with those of developed countries / Jason Peter Viljoen

    OpenAIRE

    Viljoen, Jason Peter

    2014-01-01

    The ever-changing industrial processes which are becoming more globalised as well as the merging of markets in different economies, led to an increased focus on the health and safety of workers in the industries and the mining sector over the past decades. Occupational exposure limits (OELs) have been used for more than half a century as a risk management tool for the prevention of work-related illnesses which may arise from the exposure to a wide variety of hazardous chemical substances in t...

  18. Particulate Matter Emissions Factors for Dust from Unique Military Activities

    Science.gov (United States)

    2010-06-01

    processes, together with evaporites (including artificially added potassium sulfate) serve to cement the silicate and other particles in the soils, so...processes. A sub-microscopic veneer (desert varnish) of clay minerals, with or without iron oxides generally coats the silicates, making the...dolomite, originally inter-granular cement in undisturbed dust Backscattered Electron Image (BEI) of same particle Appendix B

  19. Evaluation of exposure risk in the weaving process of MWCNT-coated yarn with real-time particle concentration measurements and characterization of dust particles.

    Science.gov (United States)

    Takaya, Mitsutoshi; Ono-Ogasawara, Mariko; Shinohara, Yasushi; Kubota, Hisayo; Tsuruoka, Shuji; Koda, Shigeki

    2012-01-01

    Various applications of multiwalled carbon nanotubes (MWCNT) have been developed. One of these applications is an efficient sheet heating element that is woven from MWCNT-coated yarn. In this research, we assessed the exposure to MWCNT and/or the probability of particle release from broken MWCNT-coated yarn during the weaving process. This was accomplished using particle concentrations, microscopic observation, and carbon analysis. In the weaving process, neither an increase in the number of particles nor a difference in particle-size distribution was observed. In the scanning electron micrographic observation, nanosize MWCNT particles were not detected, but there were micron-size particles containing MWCNT as fragments of the yarn. Carbon analysis showed the concentration of micron-size particles containing MWCNT did not exceed 0.0053 mg-C/m(3) around the loom. This value was much lower than the respirable dust mass concentration. Most of micron-size particles seemed to originate from polyester yarn without MWCNT coating. It is recommended that workers use conventional (even not specialized for nanoparticles) personal protective equipment such as respirators and gloves to prevent exposure to respirable-size MWCNT-containing particles. The probability of MWCNT fall-off from the MWCNT-coated yarn was not detected by transmission electron microscopic observation of MWCNT-coated yarn before or after the weaving process.

  20. Combined basal cell carcinoma and Langerhans cell histiocytosis of the scrotum in a patient with occupational exposure to coal tar and dust

    Energy Technology Data Exchange (ETDEWEB)

    Izikson, L.; Vanderpool, J.; Brodsky, G.; Mihm, M.C.; Zembowicz, A. [Harvard University, Boston, MA (US). Massachusetts General Hospital

    2004-09-01

    The patient was a 77-year-old male former smoker, with history of several basal cell carcinomas (BCCs) in sun-protected areas around the waistline, who presented with another small ulceration on the anterior right upper scrotum near the base of the penis. BCC was suspected clinically and the lesion was treated with cryosurgery. The tumor recurred, became raised, and began to bleed. An excisional biopsy was performed. It showed nodular BCC surrounded by a cellular proliferation of round histiocytic cells with convoluted, lobulated and reniform nuclei and abundant cytoplasm . The patient had no history of exposure to ionizing radiation, chemotherapy, immunosuppressive medications, prior lymphoma or other malignancy. However, he spent 4 years on a ship loading coal into the furnace of a steam engine, during which he slept in adjacent quarters that were covered with coal dust. Additionally, he had a several-year history of occupational skin exposure to machine oil, oil refinery waste, sulfur waste, hydraulic fluid, and asbestos. He also reported a history of nude sunbathing. The scrotal lesion was re-excised and the patient remains disease-free more than 1 year after the diagnosis.

  1. Concentration of polybrominated diphenyl ethers (PBDEs) in house hold dust from various countries. Inhalation a potential route of human exposure

    Energy Technology Data Exchange (ETDEWEB)

    Sjoedin, A. [Centers for Disease Control and Prevention (CDC), Atlanta, GA (United States); Paepke, O. [ERGO Research, Hamburg (Germany); McGahee III, E. [Centers for Disease Control and Prevention (CDC), Atlanta, GA (US)] (and others)

    2004-09-15

    Polybrominated diphenyl ethers (PBDEs) are congeners of a class of environmental contaminants that have been present in the environment for decades. PBDEs were first identified in the River Viskan in Sweden and have since then been recognized as an environmental contaminant with a global distribution as shown by the detection of this compound class in aquatic and terrestrial environments in Europe and North America. However, PBDEs will still be present in consumer products sold prior to the phase out of pentaBDE and octaBDE for decades to come. Hence it is of utmost importance to identify the exposure routes to humans especially in the Unites States where much higher levels of PBDEs have been observed in people. An average level of 34 ng/g lipid has been observed in human serum pools collected in 2002 and values in the range of 2.9-272 ng lipid (average 41ng/g lipid) have been observed in human milk. This can be contrasted to levels observed in Swedish milk pools (2.3 ng/g lipid) collected in 1997. Human exposure to persistent chemicals like polychlorinated biphenyls has traditionally been considered to be mainly through food consumption. Other direct exposure routes such as inhalation and/or dermal exposure are only of quantitatively more importance in the case of occupational exposures. However, this may or may not be true for PBDEs which are still being used in the modern indoor environment. This is further supported by the relatively low concentrations recently reported in foodstuffs sampled in the United States.

  2. ULTRA-LIGHTWEIGHT CEMENT

    Energy Technology Data Exchange (ETDEWEB)

    Fred Sabins

    2002-07-30

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report includes results from laboratory testing of ULHS systems along with other lightweight cement systems, including foamed and sodium silicate slurries. During this project quarter, a comparison study of the three cement systems examined the effect that cement drillout has on the three cement systems. Testing to determine the effect of pressure cycling on the shear bond properties of the cement systems was also conducted. This report discusses testing that was performed to analyze the alkali-silica reactivity of ULHS in cement slurries.

  3. Comparison of dust sampling methods in Estonia and Sweden--a field study.

    Science.gov (United States)

    Berg, P; Jaakmees, V; Bodin, L

    1999-09-01

    The purpose of this field study was to compare an Estonian dust sampling method, a method also used in other former East Block countries, with a Swedish method and to estimate inter-method agreement with statistical analyses. The Estonian standard method (ESM), used to assess exposure in Estonia since the early 1950s, is based on a strategy where air samples are collected for 10 minutes every hour over a full shift. This method was compared to a Swedish standard method (SSM), a modified NIOSH method, comparable to international standards, where one air sample is collected during a full shift. The study was carried out at a cement plant that in the beginning of the 1990s was subjected to an epidemiological study, including collection of exposure data. The results of the analysis from 31 clusters of parallel samples of the two methods, when dust consisting of Portland cement was collected, showed a relatively weak correlation between the SSM and the ESM, ri = 0.81 (Pearson's intra-class correlation coefficient). A conversion factor between the two methods was estimated, where SSM is 0.69 times ESM and the limits of agreement are 0.25 and 1.84, respectively. These results indicate a substantial inter-method difference. We therefore recommend that measurements obtained from the two methods should not be used interchangeably. Because the present study is of limited extent, our findings are confined to the operations studied and further studies covering other exposure situations will be needed.

  4. Contact dermatitis in cement workers in Isfahan

    Directory of Open Access Journals (Sweden)

    Iraji Fariba

    2006-01-01

    Full Text Available BACKGROUND: Due to recent industrialization and inadequately protected workers or in other words poor supervision on constructive workers habits in our large city of Isfahan cement contact dermatitis is relatively high especially among cement factory workers and constructive personnel. PURPOSES: To investigate the prevalence rate of cement contact dermatitis in cement factory workers in Isfahan. METHODS: A case-control clinical study was carried out by randomly selecing 150 factory workders and 150 official clerks in a cement factory in Isfahan in 2001. After a complete physical examination, data was recorded in observational checklists. FINDINGS: The percentages of contact dermatitis prevalences in the first and the second groups were 22% and 5.3% respectively. About 60% of cement workers with contact dermatitis were between 30-40 years of age. There was a direct relationship with age in both groups of the workers. In the high-exposure group, the hand eczema along was 70% but in the other group the percentage of involvement was the same in exposed and unexposed anatomical areas. CONCLUSIONS: There was a direct relationship between occurrence and the severity of involvement and duration of contact in the first group. Cent percent of cement workers had contact dermatitis after 10 or less years, but the percentage among the other group was 35%. LIMITATION: Irritant contact dermatitis to cement has not been detected.

  5. Dermatoses in cement workers in southern Taiwan.

    Science.gov (United States)

    Guo, Y L; Wang, B J; Yeh, K C; Wang, J C; Kao, H H; Wang, M T; Shih, H C; Chen, C J

    1999-01-01

    Construction workers are known to have occupational dermatoses. The prevalence of such dermatoses was unknown in Taiwanese construction workers. The objective of this study was to determine the work exposure, prevalence of skin manifestations, and sensitivity to common contact allergens in cement workers of southern Taiwan. A total of 1147 current regular cement workers were telephone-interviewed about skin problems during the past 12 months, work exposure, and personal protection. Among those interviewed, 166 were examined and patch tested with common contact allergens. A high % of cement workers reported skin problems in the past 12 months. More men (13.9%) reported skin problems possibly related to work than women (5.4%). Prevalence was associated with lower use of gloves, duration of work as cement worker, and more time in jobs involving direct manual handling of cement, especially tiling. A high % of dermatitis was noted in the 166 workers examined, which correlated with reported skin problems. On patch testing, construction workers had a high frequency of sensitivity to chromate. Sensitivity to chromate or cobalt was associated with reported skin problems, or dorsal hand dermatitis on examination. These workers' dermatitis was under-diagnosed and inadequately managed. It is concluded that cement workers in southern Taiwan had a high prevalence of skin problems related to cement use. Protective measures, work practice, and physician education should be improved to prevent or manage such problems.

  6. Trabalho rural, exposição a poeiras e sintomas respiratórios entre agricultores Farm work, dust exposure and respiratory symptoms among farmers

    Directory of Open Access Journals (Sweden)

    Neice Müller Xavier Faria

    2006-10-01

    Full Text Available OBJETIVO: As condições ambientais do trabalho rural, em especial a exposição às poeiras orgânicas e minerais, têm sido associadas ao aumento de doenças respiratórias. O objetivo do estudo foi avaliar a prevalência de sintomas respiratórios entre agricultores e sua associação com fatores de risco ocupacionais. MÉTODOS: Estudo de delineamento transversal com 1.379 agricultores, de Antônio Prado e Ipê, na Serra Gaúcha, em 1996. Foram coletados dados sobre características sociodemográficas e produção agrícola, bem como a exposição a poeiras orgânicas e minerais. Os sintomas respiratórios foram aferidos por meio de questionário da American Thoracic Society-Division of Lung Disease modificado. Foi realizada análise de regressão logística múltipla, controlada para fatores de confusão. RESULTADOS: A maioria (52% dos entrevistados trabalhava em atividades com exposição intensa a poeiras. Os trabalhadores de estabelecimentos com melhores indicadores econômicos referiram menor freqüência de sintomas respiratórios do que os demais agricultores. Os avicultores relataram maior prevalência de sintomas de doença respiratória crônica (OR=1,60; IC 95%: 1,05-2,42. Os agricultores com exposição intensa a poeiras apresentaram uma elevação de mais de 70% no risco de sintomas de asma (OR=1,71; IC 95%: 1,10-2,67, como também de doença respiratória crônica (OR=1,77; IC 95%: 1,25-2,50. CONCLUSÕES: Os trabalhadores rurais apresentaram grande exposição ocupacional a poeiras orgânicas e minerais. Agricultores expostos a concentrações mais elevadas, como os avicultores, tiveram maior risco de apresentar sintomas respiratórios relacionados ao trabalho. Recomenda-se a implementação de programas de proteção respiratória, principalmente para os trabalhadores envolvidos com a produção de aves.OBJECTIVE: Environmental working conditions in rural areas, notably exposure to organic and mineral dusts, have been

  7. [Biological effect of wood dust].

    Science.gov (United States)

    Maciejewska, A; Wojtczak, J; Bielichowska-Cybula, G; Domańska, A; Dutkiewicz, J; Mołocznik, A

    1993-01-01

    The biological effect of exposure to wood dust depends on its composition and the content of microorganisms which are an inherent element of the dust. The irritant and allergic effects of wood dust have been recognised for a long time. The allergic effect is caused by the wood dust of subtropical trees, e.g. western red cedar (Thuja plicata), redwood (Sequoia sempervirens), obeche (Triplochiton scleroxylon), cocabolla (Dalbergia retusa) and others. Trees growing in the European climate such as: larch (Larix), walnut (Juglans regia), oak (Quercus), beech (Fagus), pine (Pinus) cause a little less pronounced allergic effect. Occupational exposure to irritative or allergic wood dust may lead to bronchial asthma, rhinitis, alveolitis allergica, DDTS (Organic dust toxic syndrome), bronchitis, allergic dermatitis, conjunctivitis. An increased risk of adenocarcinoma of the sinonasal cavity is an important and serious problem associated with occupational exposure to wood dust. Adenocarcinoma constitutes about half of the total number of cancers induced by wood dust. An increased incidence of the squamous cell cancers can also be observed. The highest risk of cancer applies to workers of the furniture industry, particularly those dealing with machine wood processing, cabinet making and carpentry. The cancer of the upper respiratory tract develops after exposure to many kinds of wood dust. However, the wood dust of oak and beech seems to be most carcinogenic. It is assumed that exposure to wood dust can cause an increased incidence of other cancers, especially lung cancer and Hodgkin's disease. The adverse effects of microorganisms, mainly mould fungi and their metabolic products are manifested by alveolitis allergica and ODTS. These microorganisms can induce aspergillomycosis, bronchial asthma, rhinitis and allergic dermatitis.

  8. Review of technologies for mercury removal from flue gas from cement production processes

    DEFF Research Database (Denmark)

    Zheng, Yuanjing; Jensen, Anker Degn; Windelin, Christian

    2012-01-01

    to the adsorption of mercury on the solids in the cold zone. However, recirculation of the kiln dust to the kiln will cause release of the captured mercury. The mercury chemistry in cement kiln systems is complicated and knowledge obtained from power plants and incinerators cannot be directly applied in cement......Mercury is a pollutant of concern and mercury emissions from cement plants are under environmental regulation. After coal-fired power plants, mercury emissions from cement and mineral production are the second largest anthropogenic sources. Compared to fuels, cement raw materials are the major...... sources of mercury in the cement kiln flue gas. Cement plants are quite different from power plants and waste incinerators regarding the flue gas composition, temperature, residence time, and material circulation. Cement kiln systems have some inherent ability to retain mercury in the solid materials due...

  9. Magnesium oxychloride cement concrete

    Indian Academy of Sciences (India)

    A K Misra; Renu Mathur

    2007-06-01

    The scope of magnesium oxychloride (MOC) cement in concrete works has been evaluated. MOC cement concrete compositions of varying strengths having good placing and finishing characteristics were prepared and investigated for their compressive and flexural strengths, -values, abrasion resistance etc. The durability of MOC concrete compositions against extreme environmental conditions viz. heating–cooling, freezing–thawing, wetting–drying and penetration and deposition of salts etc were investigated. The results reveal that MOC concrete has high compressive strength associated with high flexural strength and the ratio of compressive to flexural strength varies between 6 and 8. The elastic moduli of the compositions studied are found to be 23–85 GPa and the abrasion losses between 0.11 and 0.20%. While alternate heating–cooling cycles have no adverse effect on MOC concrete, it can be made durable against freezing–thawing and the excessive exposure to water and salt attack by replacing 10% magnesium chloride solution by magnesium sulphate solution of the same concentration.

  10. 不同胶凝材料的精细混凝土高温后力学性能%MECHANICAL PROPERTY OF FINE GRAINED CONCRETE WITH DIFFERENT CEMENTING MATERIAL AFTER EXPOSURE TO HIGH-TEMPERATURE

    Institute of Scientific and Technical Information of China (English)

    沈玲华; 王激扬; 徐世烺; 付晔

    2015-01-01

    为了改善用于纤维编织网增强混凝土基体材料的精细混凝土的耐高温性能,该文进行了120个40mim×40mm×160mm棱柱体的高温后抗折强度试验和240个40mm×40mm×40mm立方体的高温后抗压强度试验.考察了不同胶凝材料对精细混凝土试件高温后力学性能的影响,包括外掺纳米材料以及以高铝水泥作为主要胶凝材料的影响.结果表明:体积掺量为1.5%和3.0%纳米SiO2气凝胶粉末未能改善精细混凝十的耐高温性能,质量掺量为5.0%纳米陶瓷粉在目标温度TR=800℃时使基体混凝土的抗压和抗折强度分别提高84.2%和120.9%.当TR=800℃时,采用高铝水泥作为主要胶凝材料的试件力学性能均比普通精细混凝土试件大幅提高;各组掺入活性粉末的高铝水泥混凝土试件在TR=800℃时,相对抗压和抗折强度均比未掺活性粉末时有所提高.%To improve the high temperature resistance of fine grained concrete for textile reinforced concrete matrices,120 prism specimens (40mm×40mm×160mm) for flexural tests and 240 cube specimens (40mm×40mm×40mm) were prepared in this paper for compressive strength tests after exposure to high temperature.The effects of different cementing materials on mechanical properties of fine grained concrete were studied,including the effect of nanomaterial admixtures and the use of alumina cement as main cementing material.The results show that nanometer SiO2 aerogel powder cannot improve the high temperature resistance of fine grained concrete when volume fraction is 1.5% or 3.0%.Nanosized ceramic powder with quality content of 5.0% can improve the residual compressive and flexural strength of fine grained concrete by 84.2% and 120.9%,respectively,over that of concrete without nanosized ceramic powder at 800℃.When TR=800℃,mechanical properties of specimens with alumina cement as the main cementing material increase greatly compared with ordinary fine grained

  11. Exposure to soil, house dust and decaying plants increases gut microbial diversity and decreases serum immunoglobulin E levels in BALB/c mice.

    Science.gov (United States)

    Zhou, Dongrui; Zhang, Honglin; Bai, Zhimao; Zhang, Aidi; Bai, Futian; Luo, Xing; Hou, Yue; Ding, Xiao; Sun, Beili; Sun, Xiao; Ma, Ning; Wang, Cuifen; Dai, Xiaoniu; Lu, Zuhong

    2016-05-01

    To assess the impact of sanitation of a living environment on gut microbiota and development of the immune system, we raised BALB/c mice under three distinct environmental conditions: a specific pathogen-free animal room (SPF), a general animal room (XZ) and a farmhouse (JD). All other variables like diet, age, genetic background, physiological status and original gut microbiota were controlled for in the three groups. Using high-throughput sequencing of the 16S rRNA gene, we found that each mouse group had a specific structure of the gut microbial community. Groups JD and XZ harboured a significantly more diverse and richer gut microbiota than did group SPF. Bacteroidetes were significantly more abundant in groups XZ and JD than in group SPF, whereas Firmicutes showed the inverse pattern. Total serum immunoglobulin E (IgE) levels were significantly lower in groups XZ and JD than in group SPF. There were no significant differences in gut microbiota diversity and serum IgE concentration between groups JD and XZ, but we found higher abundance of dominant genera in the gut microflora of group JD. We conclude that exposure to soil, house dust and decaying plant material enhances gut microbial diversity and innate immunity. Our results seem to provide new evidence supporting the hygiene hypothesis.

  12. Polybrominated diphenyl ethers in plastic products, indoor dust, sediment and fish from informal e-waste recycling sites in Vietnam: a comprehensive assessment of contamination, accumulation pattern, emissions, and human exposure.

    Science.gov (United States)

    Anh, Hoang Quoc; Nam, Vu Duc; Tri, Tran Manh; Ha, Nguyen Manh; Ngoc, Nguyen Thuy; Mai, Pham Thi Ngoc; Anh, Duong Hong; Minh, Nguyen Hung; Tuan, Nguyen Anh; Minh, Tu Binh

    2016-08-19

    Residue concentrations of polybrominated diphenyl ethers (PBDEs) in different kinds of samples including consumer products, indoor dust, sediment and fish collected from two e-waste recycling sites, and some industrial, urban and suburban areas in Vietnam were determined to provide a comprehensive assessment of the contamination levels, accumulation pattern, emission potential and human exposure through dust ingestion and fish consumption. There was a large variation of PBDE levels in plastic parts of obsolete electronic equipment (from 1730 to 97,300 ng/g), which is a common result observed in consumer plastic products reported elsewhere. PBDE levels in indoor dust samples collected from e-waste recycling sites ranged from 250 to 8740 ng/g, which were markedly higher than those in industrial areas and household offices. Emission rate of PBDEs from plastic parts of disposed electronic equipment to dust was estimated to be in a range from 3.4 × 10(-7) to 1.2 × 10(-5) (year(-1)) for total PBDEs and from 2.9 × 10(-7) to 7.2 × 10(-6) (year(-1)) for BDE-209. Some fish species collected from ponds in e-waste recycling villages contained elevated levels of PBDEs, especially BDE-209, which were markedly higher than those in fish previously reported. Overall, levels and patterns of PBDE accumulation in different kinds of samples suggest significant emission from e-waste sites and that these areas are potential sources of PBDE contamination. Intakes of PBDEs via fish consumption were generally higher than those estimated through dust ingestion. Intake of BDE-99 and BDE-209 through dust ingestion contributes a large proportion due to higher concentrations in dust and fish. Body weight normalized daily intake through dust ingestion estimated for the e-waste recycling sites (0.10-3.46 ng/day/kg body wt.) were in a high range as compared to those reported in other countries. Our results highlight the potential releases of PBDEs from informal recycling activities

  13. Asphalt cement poisoning

    Science.gov (United States)

    ... petroleum material that hardens when it cools. Asphalt cement poisoning occurs when someone swallows asphalt. If hot ... found in: Road paving materials Roofing materials Tile cements Asphalt may also be used for other purposes.

  14. Chloride ingress in cement paste and mortar

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, O.M.; Hansen, P.F.; Coats, A.M.; Glasser, F.P.

    1999-09-01

    In this paper chloride ingress in cement paste and mortar is followed by electron probe microanalysis. The influence of several paste and exposure parameters on chloride ingress are examined (e.g., water-cement ratio, silica fume addition, exposure time, and temperature). The measurements are modelled on Fick's law modified by a term for chloride binding. Inclusion of chloride binding significantly improves the profile shape of the modelled ingress profiles. The presence of fine aggregate and formation of interfacial transition zones at paste-aggregate boundaries does not significantly affect diffusion rates.

  15. Chemical and Physical Reactions of Wellbore Cement under CO2 Storage Conditions: Effects of Cement Additives

    Science.gov (United States)

    Kutchko, B. G.; Strazisar, B. R.; Huerta, N.; Lowry, G. V.; Dzombak, D. A.; Thaulow, N.

    2008-12-01

    Sequestration of CO2 into geologic formations requires long-term storage and low leakage rates to be effective. Active and abandoned wells in candidate storage formations must be evaluated as potential leakage points. Wellbore integrity is an important part of an overall integrated assessment program being developed at NETL to assess potential risks at CO2 storage sites. Such a program is needed for ongoing policy and regulatory decisions for geologic carbon sequestration. The permeability and integrity of the cement in the well is a primary factor affecting its ability to prevent leakage. Cement must be able to maintain low permeability over lengthy exposure to reservoir conditions in a CO2 injection and storage scenario. Although it is known that cement may be altered by exposure to CO2, the results of ongoing research indicate that cement curing conditions, fluid properties, and cement additives play a significant role in the rate of alteration and reaction. The objective of this study is to improve understanding of the factors affecting wellbore cement integrity for large-scale geologic carbon sequestration projects. Due to the high frequency use of additives (pozzolan) in wellbore cement, it is also essential to understand the reaction of these cement-pozzolan systems upon exposure to CO2 under sequestration conditions (15.5 MPa and 50°C). Laboratory experiments were performed to determine the physical and chemical changes, as well as the rate of alteration of commonly used pozzolan-cement systems under simulated sequestration reservoir conditions, including both supercritical CO2 and CO2-saturated brine. The rate of alteration of the cement-pozzolan systems is considerably faster than with neat cement. However, the alteration of physical properties is much less significant with the pozzolanic blends. Permeability of a carbonated pozzolanic cement paste remains sufficiently small to block significant vertical migration of CO2 in a wellbore. All of the

  16. The Magnetic Properties of Lichens Exposed Around a Cement Plant in Slovakia

    Science.gov (United States)

    Winkler, Aldo; Paoli, Luca; Guttová, Anna; Loppi, Stefano; Sagnotti, Leonardo

    2015-04-01

    A cement industry is a source of dust pollution, from quarrying and grinding of the raw material to kiln operations. Airborne pollutants related to combustion processes are also emitted, especially during kiln operations and power generation. The use of biomonitors can provide valuable information about the impact of airborne pollutants released during cement production and lichens are suitable bioindicators of air pollution, providing reliable information on the quality of the environment. We investigated the magnetic hysteresis properties and the elemental concentrations of epiphytic lichens from selected sites (a cement mill, two quarries, agricultural areas, and villages) in SW Slovakia; in particular, both transplanted and in situ lichens, bark, soil and rock samples from the sampling sites, as well as pre-transplant samples have been characterized. Evernia prunastri transplants, exposed up to 180 days, showed excellent correlations between the saturation magnetization (Ms) and saturation remanent magnetization (Mrs) values and the Fe concentrations; the analyzed samples were magnetically homogeneous, with marked differences only for the sample from a basalt quarry. Xanthoria parietina autochthonous samples have also a similar magnetic mineralogy; anyway their Ms and Mrs values were two orders of magnitude higher with respect to those from the transplants, implying increased concentration of magnetic particles according to the different lichen species and to the prolonged exposure. Magnetic methods can be valuable for discriminating various natural and anthropogenic sources of dust. In this study, we point out that the magnetic properties may also reflect the influence of the basalt quarry activity, of the soil and of the bedrock. For a proper evaluation of the pollution related to human activities, it is thus essential to verify the nature of the substrate and to select suitable and homogeneous pre/post lichen transplant sites.

  17. Neutralization of TSLP inhibits airway remodeling in a murine model of allergic asthma induced by chronic exposure to house dust mite.

    Directory of Open Access Journals (Sweden)

    Zhuang-Gui Chen

    Full Text Available Chronic allergic asthma is characterized by Th2-typed inflammation, and contributes to airway remodeling and the deterioration of lung function. However, the initiating factor that links airway inflammation to remodeling is unknown. Thymic stromal lymphopoietin (TSLP, an epithelium-derived cytokine, can strongly activate lung dendritic cells (DCs through the TSLP-TSLPR and OX40L-OX40 signaling pathways to promote Th2 differentiation. To determine whether TSLP is the underlying trigger of airway remodeling in chronic allergen-induced asthma, we induced allergic airway inflammation in mice by intranasal administration of house dust mite (HDM extracts for up to 5 consecutive weeks. We showed that repeated respiratory exposure to HDM caused significant airway eosinophilic inflammation, peribronchial collagen deposition, goblet cell hyperplasia, and airway hyperreactivity (AHR to methacholine. These effects were accompanied with a salient Th2 response that was characterized by the upregulation of Th2-typed cytokines, such as IL-4 and IL-13, as well as the transcription factor GATA-3. Moreover, the levels of TSLP and transforming growth factor beta 1 (TGF-β1 were also increased in the airway. We further demonstrated, using the chronic HDM-induced asthma model, that the inhibition of Th2 responses via neutralization of TSLP with an anti-TSLP mAb reversed airway inflammation, prevented structural alterations, and decreased AHR to methacholine and TGF-β1 level. These results suggest that TSLP plays a pivotal role in the initiation and persistence of airway inflammation and remodeling in the context of chronic allergic asthma.

  18. Dechlorane Plus in house dust from E-waste recycling and urban areas in South China: sources, degradation, and human exposure.

    Science.gov (United States)

    Wang, Jing; Tian, Mi; Chen, She-Jun; Zheng, Jing; Luo, Xiao-Jun; An, Tai-Cheng; Mai, Bi-Xian

    2011-09-01

    Dechlorane Plus (DP) was measured in house dust from e-waste recycling and from urban and rural areas of South China, with geometric mean concentrations of 604, 14.5, and 2.89 ng/g, respectively. Dechlorane Plus in house dust in the e-waste area originated from e-waste recycling activities, whereas household appliances served as a major source of DP in urban house dust. The isomer ratios (f(anti) ) of DP in most dust samples from the e-waste area were significantly lower than those in the urban and rural dust samples and the commercial mixture. Several [-1Cl + H] and [-2Cl + 2H] dechloro-DPs were identified in house dust from the e-waste area, and an a-Cl(11) DP was qualified with concentrations of <55.1 ng/g. Photolytic degradation experiments were conducted by exposing anti-DP, syn-DP, and commercial DP solutions to ultraviolet (UV) light. The slight difference in isomeric half-life derived by photodegradation, as well as the lower f(anti) values in the e-waste combusted residue, suggest a significant influence of isomer-specific thermal degradation of DP during e-waste burning on isomer composition in house dust in the e-waste area. The average estimated daily intakes (EDIs) of DP via house dust ranged from 0.06 to 30.2 ng/d for adults and 0.14 to 121 ng/d for toddlers in the studied area. The average EDIs of a-Cl(11) DP for adults and toddlers in the e-waste area were 0.07 and 0.18 ng/d, respectively.

  19. Hydration Characteristics and Immobilization of Cr (VI) in Slag Cement-CKD Pastes under Hydrothermal Treatment

    Institute of Scientific and Technical Information of China (English)

    M R Shatat; Gomaa A M Ali; M A Tantawy

    2015-01-01

    The effect of hydrothermal curing regimes on the hydration characteristics of slag cement containing different ratios of cement kiln dust has been studied. The samples for this study were combination of slag cement and cement kiln dust (5%-25%) without and with immobilization of 5% Cr (VI) by mass. Pastes were hydrothermally treated at 180℃ for different periods (2-24 h) in well closed stainless steel capsule. The hydration characteristics of these pastes were studied by measuring the compressive strength, bulk density, total porosity and combined water content. The findings were further supported by XRD and SEM analysis. The results indicated that the hydration characteristics of slag cement paste containing cement kiln dust 10% by mass were enhanced, especially at later ages (24 h) of hydration. That is due to the hydrothermal curing regimes of immobilized pastes accelerating hydration reactions and precipitation of CaCrO4, indicating that Cr (VI) can be solidiifed in the cement paste. This precipitation leads to pore formation in hydrated slag cement pastes.

  20. Characteristics of mercury cycling in the cement production process.

    Science.gov (United States)

    Wang, Fengyang; Wang, Shuxiao; Zhang, Lei; Yang, Hai; Wu, Qingru; Hao, Jiming

    2016-01-25

    The mercury cycling caused by dust shuttling significantly increases the atmospheric emissions from cement production. A comprehensive understanding of this mercury cycling can promote the development of mercury emission control technologies. In this study, the characteristics of mercury cycling in the cement production process were first investigated. Furthermore, the mercury enrichment and effects of dust treatment were evaluated based on the field tests conducted in two Chinese cement plants. The mercury cycling between the kiln system and the raw mill system was the most important aspect and contributed 57-73% to the total amount of mercury emitted from the kiln system. Mercury emitted from the kiln system with flue gas was enriched as high as 3.4-8.8 times in the two tested plants compared to the amount of mercury in the raw materials and coal due to mercury cycling. The mercury enrichment can be significantly affected by the proportion of mercury cycled back to the kiln system. The effects of dust treatment were evaluated, and dust treatment can efficiently reduce approximately 31-70% of atmospheric mercury emissions in the two plants. The reduction proportion approximately linearly decreased with the proportion of mercury removed from the collected dust.

  1. Allergies, asthma, and dust

    Science.gov (United States)

    Reactive airway disease - dust; Bronchial asthma - dust; Triggers - dust ... Things that make allergies or asthma worse are called triggers. Dust is a common trigger. When your asthma or allergies become worse due to dust, you are ...

  2. Health risk assessment of migrant workers' exposure to polychlorinated biphenyls in air and dust in an e-waste recycling area in China: Indication for a new wealth gap in environmental rights.

    Science.gov (United States)

    Wang, Yalin; Hu, Jinxing; Lin, Wei; Wang, Ning; Li, Cheng; Luo, Peng; Hashmi, Muhammad Zaffar; Wang, Wenbo; Su, Xiaomei; Chen, Chen; Liu, Yindong; Huang, Ronglang; Shen, Chaofeng

    2016-02-01

    Migrant workers who work and live in polluted environment are a special vulnerable group in the accelerating pace of urbanization and industrialization in China. In the electronic waste (e-waste) recycling area, for example, migrant workers' exposure to pollutants, such as PCBs (polychlorinated biphenyls), is the result of an informal e-waste recycling process. A village in an electronic waste recycling area where migrant workers gather was surveyed. The migrant workers' daily routines were simulated according to the three-space transition: work place-on the road-home. Indoor air and dust in the migrant workers' houses and workplaces and the ambient air on the roads were sampled. The PCB levels of the air and dust in the places corresponding to the migrant workers are higher than those for local residents. The migrant workers have health risks from PCBs that are 3.8 times greater than those of local residents. This is not only caused by the exposure at work but also by their activity patterns and the environmental conditions of their dwellings. These results revealed the reason for the health risk difference between the migrant workers and local residents, and it also indicated that lifestyle and economic status are important factors that are often ignored compared to occupational exposure.

  3. Lead and other elements in house dust of Japanese residences--source of lead and health risks due to metal exposure.

    Science.gov (United States)

    Yoshinaga, Jun; Yamasaki, Kumiko; Yonemura, Ayumi; Ishibashi, Yuri; Kaido, Takaya; Mizuno, Kodai; Takagi, Mai; Tanaka, Atsushi

    2014-06-01

    The levels of 25 elements in house dust collected from 100 general Japanese residences were measured. Factor analysis was applied on the multi-element data to explore source of Pb (median concentration 49.1 mg/kg) in house dust. Six factors were extracted and Pb was found to have great loading on the fifth factor with Sb and Sn, suggesting solder (Sn), and plastic and metals (Sb) may be the sources of Pb in the house dust of Japanese residences. No significant loading was found on soil-related factors indicating non-significant contribution of Pb in track-in soil. Seven heavy metals (Cd, Cu, Mo, Pb, Sb, Sn, and Zn) were found in house dust at >10 times more condensed than crustal abundance. Health risk of these elements to children via the ingestion of house dust was estimated based on the comparison with tolerable daily intake and found to be non-significant for most of the elements.

  4. Polycyclic Aromatic Hydrocarbons in Residential Dust: Sources of Variability

    OpenAIRE

    Whitehead, Todd P; Metayer, Catherine; Petreas, Myrto; Does, Monique; Buffler, Patricia A.; Rappaport, Stephen M.

    2013-01-01

    Background: There is interest in using residential dust to estimate human exposure to environmental contaminants. Objectives: We aimed to characterize the sources of variability for polycyclic aromatic hydrocarbons (PAHs) in residential dust and provide guidance for investigators who plan to use residential dust to assess exposure to PAHs. Methods: We collected repeat dust samples from 293 households in the Northern California Childhood Leukemia Study during two sampling rounds (from 2001 thr...

  5. Effective Permeability Change in Wellbore Cement with Carbon Dioxide Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Um, Wooyong; Jung, Hun Bok; Martin, Paul F.; McGrail, B. Peter

    2011-11-01

    Portland cement, a common sealing material for wellbores for geological carbon sequestration was reacted with CO{sub 2} in supercritical, gaseous, and aqueous phases at various pressure and temperature conditions to simulate cement-CO{sub 2} reaction along the wellbore from carbon injection depth to the near-surface. Hydrated Portland cement columns (14 mm diameter x 90 mm length; water-to-cement ratio = 0.33) including additives such as steel coupons and Wallula basalt fragments were reacted with CO{sub 2} in the wet supercritical (the top half) and dissolved (the bottom half) phases under carbon sequestration condition with high pressure (10 MPa) and temperature (50 C) for 5 months, while small-sized hydrated Portland cement columns (7 mm diameter x 20 mm length; water-to-cement ratio = 0.38) were reacted with CO{sub 2} in dissolved phase at high pressure (10 MPa) and temperature (50 C) for 1 month or with wet CO{sub 2} in gaseous phase at low pressure (0.2 MPa) and temperature (20 C) for 3 months. XMT images reveal that the cement reacted with CO{sub 2} saturated groundwater had degradation depth of {approx}1 mm for 1 month and {approx}3.5 mm for 5 month, whereas the degradation was minor with cement exposure to supercritical CO{sub 2}. SEM-EDS analysis showed that the carbonated cement was comprised of three distinct zones; the innermost less degraded zone with Ca atom % > C atom %, the inner degraded zone with Ca atom % {approx} C atom % due to precipitation of calcite, the outer degraded zone with C atom % > Ca atom % due to dissolution of calcite and C-S-H, as well as adsorption of carbon to cement matrix. The outer degraded zone of carbonated cement was porous and fractured because of dissolution-dominated reaction by carbonic acid exposure, which resulted in the increase in BJH pore volume and BET surface area. In contrast, cement-wet CO{sub 2}(g) reaction at low P (0.2 MPa)-T (20 C) conditions for 1 to 3 months was dominated by precipitation of micron

  6. The dissolution of natural and artificial dusts in glutamic acid

    Science.gov (United States)

    Ling, Zhang; Faqin, Dong; Xiaochun, He

    2015-06-01

    This article describes the characteristics of natural dusts, industrial dusts, and artificial dusts, such as mineral phases, chemical components, morphological observation and size. Quartz and calcite are the main phases of natural dusts and industrial dusts with high SiO2 and CaO and low K2O and Na2O in the chemical composition. The dissolution and electrochemical action of dusts in glutamic acid liquor at the simulated human body temperature (37 °C) in 32 h was investigated. The potential harm that the dust could lead to in body glutamic acid acidic environment, namely biological activity, is of great importance for revealing the human toxicological mechanism. The changes of pH values and electric conductivity of suspension of those dusts were similar, increased slowly in the first 8 h, and then the pH values increased rapidly. The total amount of dissolved ions of K, Ca, Na, and Mg was 35.4 to 429 mg/kg, particularly Ca was maximal of 20 to 334 mg/kg. The total amount of dissolved ions of Fe, Zn, Mn, Pb, and Ba was 0.18 to 5.59 mg/kg and in Al and Si was 3.0 to 21.7 mg/kg. The relative solubility order of dusts in glutamic acid is wollastonite > serpentine > sepiolite, the cement plant industrial dusts > natural dusts > power plant industrial dusts. The wollastonite and cement plant industrial dusts have the highest solubility, which also have high content of CaO; this shows that there are a poorer corrosion-resisting ability and lower bio-resistibility. Sepiolite and power plant industrial dusts have lowest solubility, which also have high content of SiO2; this shows that there are a higher corrosion-resisting ability and stronger bio-resistibility.

  7. ULTRA-LIGHTWEIGHT CEMENT

    Energy Technology Data Exchange (ETDEWEB)

    Fred Sabins

    2002-01-23

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report includes results from laboratory testing of ULHS systems along with other lightweight cement systems: foamed and sodium silicate slurries. Comparison studies of the three cement systems examined several properties: tensile strength, Young's modulus, water permeability, and shear bond. Testing was also done to determine the effect that temperature cycling has on the shear bond properties of the cement systems. In addition, analysis was carried out to examine alkali silica reactivity of slurries containing ULHS. Data is also presented from a study investigating the effects of mixing and pump circulation on breakage of ULHS. Information is also presented about the field application of ULHS in cementing a 7-in. intermediate casing in south Texas.

  8. Pulmonary Toxicity Studies of Lunar Dusts in Rodents

    Science.gov (United States)

    Lam, Chiu-wing; James, John T.

    2009-01-01

    NASA will build an outpost on the lunar surface for long-duration human habitation and research. The surface of the Moon is covered by a layer of fine, reactive dust, and the living quarters in the lunar outpost are expected to be contaminated by lunar dust. Because the toxicity of lunar dust is not known, NASA has tasked its toxicology laboratory to evaluate the risk of exposure to the dust and to establish safe exposure limits for astronauts working in the lunar habitat. Studies of the pulmonary toxicity of a dust are generally done first in rodents by intratracheal/intrapharyngeal instillation. This toxicity screening test is then followed by an inhalation study, which requires much more of the test dust and is labor intensive. Preliminary results obtained by examining lung lavage fluid from dust-treated mice show that lunar dust was somewhat toxic (more toxic than TiO2, but less than quartz dust). More extensive studies are in progress to further examine lung lavage fluid for biomarkers of toxicity and lung tissues for histopathological lesions in rodents exposed to aged and activated (ground) lunar dust samples. In these studies, reference dusts (TiO2 and quartz) of known toxicities and have industrial exposure limits will be studied in parallel so the relative toxicity of lunar dust can be determined. The results from the instillation studies will be useful for choosing exposure concentrations for the animal inhalation study. The animal inhalation exposure will be conducted with lunar dust simulant prior to the study with the lunar dust. The experiment with the simulate will ensure that the study techniques used with actual lunar dust will be successful. The results of instillation and inhalation studies will reveal the toxicological risk of exposures and are essential for setting exposure limits on lunar dust for astronauts living in the lunar habitat.

  9. Impact of Alkaline Dust Pollution on Soil Microbial Biomass Carbon

    OpenAIRE

    Kara, Ömer; Bolat, İlyas

    2007-01-01

    The effect of alkaline dust pollution emitted from Bartın cement plant on the soil microbial biomass carbon was investigated using the chloroform fumigation-extraction (CFE) method. Microbial biomass C (Cmic) values ranged from 157.82 to 1201.51 µg g-1 soils in the polluted area and from 726.70 to 1529.14 µg g-1 soils in the control area. Soils polluted with alkaline cement dust resulted in significant reductions in Cmic levels compared to control soils. Microbial biomass C correlated negativ...

  10. Impact of Alkaline Dust Pollution on Soil Microbial Biomass Carbon

    OpenAIRE

    KARA, Ömer; Bolat, İlyas

    2014-01-01

    The effect of alkaline dust pollution emitted from Bartın cement plant on the soil microbial biomass carbon was investigated using the chloroform fumigation-extraction (CFE) method. Microbial biomass C (Cmic) values ranged from 157.82 to 1201.51 µg g-1 soils in the polluted area and from 726.70 to 1529.14 µg g-1 soils in the control area. Soils polluted with alkaline cement dust resulted in significant reductions in Cmic levels compared to control soils. Microbial biomass C correlated negativ...

  11. Concentrations of polybrominated diphenyl ethers (PBDEs) in central air-conditioner filter dust and relevance of non-dietary exposure in occupational indoor environments in Greece.

    Science.gov (United States)

    Besis, Athanasios; Katsoyiannis, Athanasios; Botsaropoulou, Elisavet; Samara, Constantini

    2014-05-01

    Polybrominated Diphenyl Ethers (PBDEs) are ubiquitous in the indoor environment owing to their use in consumer products and various studies around the world have found higher concentrations indoors than outdoors. Central air conditioner (A/C) systems have been widely used in many workplaces, therefore, studying of PBDEs in central A/C filter dust is useful to better understand the occurrences and health implications of PBDEs in indoor environments. The present study examined the occurrence of PBDEs in central A/C filter dust collected from various workplaces (n = 20) in Thessaloniki, Greece. The sum concentrations of 21 target congeners (∑21PBDE) in A/C dust ranged between 84 and 4062 ng g(-1) with a median value of 1092 ng g(-1), while BDE-209 was found to be the most abundant BDE congener. The daily intake via dust ingestion of PBDEs estimated for the employees of the occupational settings ranged from 3 to 45 ng day(-1) (median 12 ng day(-1)).

  12. Stimuli-responsive cement-reinforced rubber.

    Science.gov (United States)

    Musso, Simone; Robisson, Agathe; Maheshwar, Sudeep; Ulm, Franz-Josef

    2014-05-14

    In this work, we report the successful development of a cement-rubber reactive composite with reversible mechanical properties. Initially, the composite behaves like rubber containing inert filler, but when exposed to water, it increases in volume and reaches a stiffness that is intermediate between that of hydrogenated nitrile butadiene rubber (HNBR) and hydrated cement, while maintaining a relatively large ductility characteristic of rubber. After drying, the modulus increases even further up to 400 MPa. Wet/drying cycles prove that the elastic modulus can reversibly change between 150 and 400 MPa. Utilizing attenuated total reflection Fourier transform infrared spectroscopy), we demonstrate that the high pH produced by the hydration of cement triggers the hydrolysis of the rubber nitrile groups into carboxylate anions. Thus, the salt bridges, generated between the carboxylate anions of the elastomer and the cations of the filler, are responsible for the reversible variations in volume and elastic modulus of the composite as a consequence of environmental moisture exposure. These results reveal that cement nanoparticles can successfully be used to accomplish a twofold task: (a) achieve an original postpolymerization modification that allows one to work with carboxylate HNBR (HXNBR) not obtained by direct copolymerization of carboxylate monomers with butadiene, and (b) synthesize a stimuli-responsive polymeric composite. This new type of material, having an ideal behavior for sealing application, could be used as an alternative to cement for oil field zonal isolation applications.

  13. Nasal cancer and occupational exposures. Preliminary report of a joint Nordic case-referent study

    DEFF Research Database (Denmark)

    Hernberg, S; Collan, Y; Degerth, R

    1983-01-01

    showed a connection with adenocarcinoma. Softwood dust exposure alone was associated with epidermoid and anaplastic carcinomas. No associations were found for a number of exposures, including agricultural chemicals, textile dust, asbestos, quartz dust, organic solvents, and leather work. Possible...

  14. Tympanoplasty with ionomeric cement

    DEFF Research Database (Denmark)

    Kjeldsen, A D; Grøntved, A M

    2000-01-01

    with isolated erosion of the long incus process have been treated with a new surgical technique in which the ossicular chain was rebuilt with ionomeric cement. The results in hearing performance (mean pure-tone average (PTA) 0.5, 1 and 2 kHz) were evaluated pre- and post-surgery, and compared to those...... of > 10 dB, in 4 there was a slight improvement and in 2 a decline. The difference was not statistically significant. Hearing improvement using ionomeric cement in type II tympanoplasty was satisfactory. Reconstruction of the ossicular chain with ionomeric cement is recommended, as the procedure is easy...

  15. Cement and concrete

    Science.gov (United States)

    Corley, Gene; Haskin, Larry A.

    1992-01-01

    To produce lunar cement, high-temperature processing will be required. It may be possible to make calcium-rich silicate and aluminate for cement by solar heating of lunar pyroxene and feldspar, or chemical treatment may be required to enrich the calcium and aluminum in lunar soil. The effects of magnesium and ferrous iron present in the starting materials and products would need to be evaluated. So would the problems of grinding to produce cement, mixing, forming in vacuo and low gravity, and minimizing water loss.

  16. POZZOLAN AND CEMENTS WITH POZZOLAN

    OpenAIRE

    Hasan KAPLAN; Hanifi BİNİCİ

    1995-01-01

    Cement, one of the basic material of construction engineering, has an important place in view of strength and cost of structures. Cement consumption is increasing parallel to development of building construction sector. For cement producers, minimal cost is desired by using new and economical material sources. On the other hand, the controllers and contractors need cheaper, safer and higher strength materials. From this respect cement industry tends to use cement with pozzolan. In Türkiye, ce...

  17. [Effect of lunar dust on humans: -lunar dust: regolith-].

    Science.gov (United States)

    Morimoto, Yasuo; Miki, Takeo; Higashi, Toshiaki; Horie, Seichi; Tanaka, Kazunari; Mukai, Chiaki

    2010-09-01

    We reviewed the effect of lunar dust (regolith) on humans by the combination of the hazard/exposure of regolith and microgravity of the moon. With regard to the physicochemical properties of lunar dust, the hazard-related factors are its components, fibrous materials and nanoparticles. Animal exposure studies have been performed using a simulant of lunar dust, and it was speculated that the harmful effects of the simulant lies between those of crystalline silica and titanium dioxide. Fibrous materials may not have a low solubility judging from their components. The nanoparticles in lunar dust may have harmful potentials from the view of the components. As for exposure to regolith, there is a possibility that particles larger than ones in earth (1 gravity) are respirable. In microgravity, 1) the deposition of particles of less than 1 µm in diameter in the human lung did not decrease, 2) the functions of macrophages including phagocytosis were suppressed, 3) pulmonary inflammation was changed. These data on hazard/exposure and microgravity suggest that fine and ultrafine particles in regolith may have potential hazards and risks for humans.

  18. Do cement nanoparticles exist in space ?

    CERN Document Server

    Bilalbegovic, G; Mohacek-Grosev, V

    2014-01-01

    The calcium-silicate-hydrate is used to model properties of cement on Earth. We study cementitious nanoparticles and propose these structures as components of cosmic dust grains. Quantum density functional theory methods are applied for the calculation of infrared spectra of Ca4Si4O14H4, Ca6Si3O13H2, and Ca12Si6O26H4 clusters. We find bands distributed over the near, mid and far-infrared region. A specific calcium-silicate-hydrate spectral feature at 14 microns, together with the bands at 10 and 18 microns which exist for other silicates as well, could be used for a detection of cosmic cement. We compare calculated bands with the 14 microns features in the spectra of HD 45677, HD 44179, and IRC+10420 which were observed by Infrared Space Observatory and classified as remaining. High abundance of oxygen atoms in cementitious nanoparticles could partially explain observed depletion of this element from the interstellar medium into dust grains.

  19. Dust Devil Tracks

    Science.gov (United States)

    Reiss, Dennis; Fenton, Lori; Neakrase, Lynn; Zimmerman, Michael; Statella, Thiago; Whelley, Patrick; Rossi, Angelo Pio; Balme, Matthew

    2016-11-01

    Dust devils that leave dark- or light-toned tracks are common on Mars and they can also be found on the Earth's surface. Dust devil tracks (hereinafter DDTs) are ephemeral surface features with mostly sub-annual lifetimes. Regarding their size, DDT widths can range between ˜1 m and ˜1 km, depending on the diameter of dust devil that created the track, and DDT lengths range from a few tens of meters to several kilometers, limited by the duration and horizontal ground speed of dust devils. DDTs can be classified into three main types based on their morphology and albedo in contrast to their surroundings; all are found on both planets: (a) dark continuous DDTs, (b) dark cycloidal DDTs, and (c) bright DDTs. Dark continuous DDTs are the most common type on Mars. They are characterized by their relatively homogenous and continuous low albedo surface tracks. Based on terrestrial and martian in situ studies, these DDTs most likely form when surficial dust layers are removed to expose larger-grained substrate material (coarse sands of ≥500 μm in diameter). The exposure of larger-grained materials changes the photometric properties of the surface; hence leading to lower albedo tracks because grain size is photometrically inversely proportional to the surface reflectance. However, although not observed so far, compositional differences (i.e., color differences) might also lead to albedo contrasts when dust is removed to expose substrate materials with mineralogical differences. For dark continuous DDTs, albedo drop measurements are around 2.5 % in the wavelength range of 550-850 nm on Mars and around 0.5 % in the wavelength range from 300-1100 nm on Earth. The removal of an equivalent layer thickness around 1 μm is sufficient for the formation of visible dark continuous DDTs on Mars and Earth. The next type of DDTs, dark cycloidal DDTs, are characterized by their low albedo pattern of overlapping scallops. Terrestrial in situ studies imply that they are formed when sand

  20. House dust in seven Danish offices

    Science.gov (United States)

    Mølhave, L.; Schneider, T.; Kjærgaard, S. K.; Larsen, L.; Norn, S.; Jørgensen, O.

    Floor dust from Danish offices was collected and analyzed. The dust was to be used in an exposure experiment. The dust was analyzed to show the composition of the dust which can be a source of airborne dust indoors. About 11 kg of dust from vacuum cleaner bags from seven Danish office buildings with about 1047 occupants (12 751 m 2) was processed according to a standardized procedure yielding 5.5 kg of processed bulk dust. The bulk dust contained 130.000-160.000 CFU g -1 microorganisms and 71.000-90.000 CFU g -1 microfungi. The content of culturable microfungi was 65-123 CFU 30 g -1 dust. The content of endotoxins ranged from 5.06-7.24 EU g -1 (1.45 ng g -1 to 1.01 ng g -1). Allergens (ng g -1) were from 147-159 (Mite), 395-746 (dog) and 103-330 (cat). The macro molecular organic compounds (the MOD-content) varied from 7.8-9.8 mg g -1. The threshold of release of histamine from basophil leukocytes provoked by the bulk dust was between 0.3 and 1.0 mg ml -1. The water content was 2% (WGT) and the organic fraction 33%. 6.5-5.9% (dry) was water soluble. The fiber content was less than 0.2-1.5% (WGT) and the desorbable VOCs was 176-319 μg g -1. Most of the VOC were aldehydes. However, softeners for plastic (DBP and DEHP) were present. The chemical composition includes human and animal skin fragments, paper fibers, glass wool, wood and textilefibers and inorganic and metal particles. The sizes ranged from 0.001-1 mm and the average specific density was 1.0 g m -3. The bulk dust was resuspended and injected into an exposure chamber. The airborne dust was sampled and analyzed to illustrate the exposures that can result from sedimented dirt and dust. The airborne dust resulting from the bulk dust reached concentrations ranging from 0.26-0.75 mg m -3 in average contained 300-170 CFU m -3. The organic fraction was from 55-70% and the water content about 2.5% (WGT). The content of the dust was compared to the similar results reported in the literature and its toxic potency is

  1. Genomic analysis of lung cell lines exposures to space radiation and the effect of lunar dust on selected fibrosis gene using RT2 PCR Array

    Science.gov (United States)

    Yeshitla, Samrawit

    In the United States (U.S.), lung cancer is the number one cause of cancer death among men and women. Previous studies on human and animal epithelial lung cells showed that ionizing radiation and certain environmental pollutants are carcinogens. The surface area of the lungs and the slow turnover rate of the epithelial cells are suggested to play a role in the vulnerability of the cells, which lead to increase in the progenitor cell of the lung. It has been proposed that these progenitor cells, when exposed to radiation undergo multiple alterations that cause the cells to become cancerous. The current thought is that the lungs contain several facultative progenitor cells that are situated throughout the lung epithelium and are regionally restricted in their regenerative capacity. In this study, normal Human Bronchial Epithelial Cells (HBECs) were immortalized through the expression of Cdk4 and hTERT and evaluated for the effects radiation using in vitro study. The HBECs retained its novel multipotent capacity in vitro and represented unrestricted progenitor cells of the adult lungs, which resemble an embryonic progenitor. Analysis of the transformed clones of human bronchial epithelial cell line, HEBC3KT exposed to Fe ions and gamma rays revealed chromosomal abnormality, which was detected with the Multi-color Fluorescent In Situ Hybridization (mFish). In Part two of this study the F344 rats exposed to lunar dust, for 4 weeks (6h/d; 5d/wk.) in nose-only inhalation chambers at concentrations of 0 (control air), 2.1, 6.8, 20.8, and 61 mg/m3 of lunar dust, were used to determine the lunar dust toxicity on the lung tissues and total RNA were prepared from the tissues and used for gene expression. Analysis of gene expression data using Ingenuity Pathway Analysis tool identified multiple pathways of which fibrosis was one of the pathways. The Rat Fibrosis RT 2 Profile PCR Array was used to profile the expression of 84 genes that are relevant to fibrosis in the lung

  2. Type 2 diabetes in Mexican workers exponed to a potential source of dioxins in the cement industry determined by a job exposure matrix Diabetes tipo 2 en trabajadores Mexicanos expuestos a una fuente potencial de dioxinas en la industria del cemento determinado a través de una matriz de exposición ocupacional

    Directory of Open Access Journals (Sweden)

    Luis Haro-García

    2010-06-01

    Full Text Available Purpose: To identify association between type 2 diabetes (DM2 with occupational exposure to potential dioxins source in Mexican cement industry workers. Materials and Methods: 56 medical files of cement industry workers with diagnosis of DM2 were included; 56 medical files of workers from the same industry without DM2 were the controls. The daily dose of exposure (DDE to the potential dioxins source per work years was estimated by a job exposure matrix and categorized as low, moderate, and high. Logistic regression model that correlated high exposure to potential source of dioxins (cement clinker confinement per work years and presence of DM2 was adjusted by work seniority, patient age at which DM2 diagnosis was established and DM2 familiar background. Results: the OR for the presence of DM2 in workers with moderate and high exposure to potential source of dioxins in the cement industry was 3.25 (1.10-9.57, p= 0.03, adjusted by work seniority, worker age at which DM2 diagnosis was established, and DM2 familiar background. Conclusions: In according with the data explored in the medical files of cement industry workers, there is an association between high exposure to the industrial confinement of the cement clinker as a potential source of dioxins and presence of DM2 in a modest dose-response gradient.Propósito: Identificar asociación entre diabetes tipo 2 (DM2 en trabajadores Mexicanos con la exposición ocupacional a una fuente potencial de dioxinas de la industria cementera. Material y métodos: Se incluyeron 56 expedientes clínicos de trabajadores de la industria cementera con diagnóstico de DM2; los controles lo constituyeron 56 expedientes clínicos de trabajadores de la misma industria pero sin DM2. La dosis diaria de exposición (DDE a la fuente potencial de dioxinas por años trabajados se estimó a través de una matriz de exposición ocupacional y fue categorizada como baja, moderada y alta. El modelo de regresión logística que

  3. Airborne exposures and risk of gastric cancer: a prospective cohort study.

    Science.gov (United States)

    Sjödahl, Krister; Jansson, Catarina; Bergdahl, Ingvar A; Adami, Johanna; Boffetta, Paolo; Lagergren, Jesper

    2007-05-01

    There is an unexplained male predominance among patients with gastric cancer, and many carcinogens are found in male-dominated dusty occupations. However, the relation between occupational exposures and risk of gastric cancer remains unclear. To investigate whether airborne occupational exposures might influence the risk of noncardia gastric cancer, we used a large, prospective cohort study of male Swedish construction workers. These workers were, during the period 1971-1993, regularly invited to health examinations by a nationwide occupational health service organization. Data on job titles and other variables were collected through self-administered questionnaires and forms completed by the health organization's staff. Industrial hygienists assessed 12 specific airborne occupational exposures for 200 job titles. Gastric cancer, death or emigration occurring during follow-up in 1971-2002 were identified by linkage to the Swedish registers of Cancer, Causes of Death and Total Population, respectively. Incidence rate ratios (IRR) and 95% confidence intervals (CI), adjusted for attained age, tobacco smoking, calendar period and body mass, were derived from Cox regression. Among 256,357 cohort members, contributing 5,378,012 person-years at risk, 948 noncardia gastric cancers were identified. Increased risk of this tumor was found among workers exposed to cement dust (IRR 1.5 [95% CI 1.1-2.1]), quartz dust (IRR 1.3 [95% CI 1.0-1.7]) and diesel exhaust (IRR 1.4 [95% CI 1.1-1.9]). Dose-response relations were observed for these exposures. No consistent positive associations were found regarding exposure to asbestos, asphalt fumes, concrete dust, epoxy resins, isocyanates, metal fumes, mineral fibers, organic solvents or wood dust. In conclusion, this study provides some support to the hypothesis that specific airborne exposures increase the risk of noncardia gastric cancer.

  4. Occupational Exposures and Chronic Airflow Limitation

    Directory of Open Access Journals (Sweden)

    Helen Dimich-Ward

    1996-01-01

    Full Text Available The recent literature was reviewed to evaluate whether chronic airflow limitation is associated with occupational exposures to dusts. Only those studies that controlled for the effects of smoking were included. There is compelling evidence that exposure to inorganic dusts, such as from coal and hardrock mining or asbestos, are associated with the development of chronic airflow limitation, independently of pneumoconiosis. Nonsmoking gold miners are particularly at high risk of airflow obstruction and emphysema. Findings from studies of organic dusts, such as exposures to wood, cotton, grain or other agricultural dusts, or to mixed dust exposures, were less consistent but tended to show positive dose-response associations. In the majority of studies, no statistical interaction was shown between dust exposures and smoking; however, the effects of the dust exposures were often more pronounced. An occupational history should be considered, in addition to a smoking history, as an integral part of an investigation of chronic airflow limitation in a patient.

  5. Durability of pulp fiber-cement composites

    Science.gov (United States)

    Mohr, Benjamin J.

    Wood pulp fibers are a unique reinforcing material as they are non-hazardous, renewable, and readily available at relatively low cost compared to other commercially available fibers. Today, pulp fiber-cement composites can be found in products such as extruded non-pressure pipes and non-structural building materials, mainly thin-sheet products. Although natural fibers have been used historically to reinforce various building materials, little scientific effort has been devoted to the examination of natural fibers to reinforce engineering materials until recently. The need for this type of fundamental research has been emphasized by widespread awareness of moisture-related failures of some engineered materials; these failures have led to the filing of national- and state-level class action lawsuits against several manufacturers. Thus, if pulp fiber-cement composites are to be used for exterior structural applications, the effects of cyclical wet/dry (rain/heat) exposure on performance must be known. Pulp fiber-cement composites have been tested in flexure to examine the progression of strength and toughness degradation. Based on scanning electron microscopy (SEM), environmental scanning electron microscopy (ESEM), energy dispersive spectroscopy (EDS), a three-part model describing the mechanisms of progressive degradation has been proposed: (1) initial fiber-cement/fiber interlayer debonding, (2) reprecipitation of crystalline and amorphous ettringite within the void space at the former fiber-cement interface, and (3) fiber embrittlement due to reprecipitation of calcium hydroxide filling the spaces within the fiber cell wall structure. Finally, as a means to mitigate kraft pulp fiber-cement composite degradation, the effects of partial portland cement replacement with various supplementary cementitious materials (SCMs) has been investigated for their effect on mitigating kraft pulp fiber-cement composite mechanical property degradation (i.e., strength and toughness

  6. ULTRA-LIGHTWEIGHT CEMENT

    Energy Technology Data Exchange (ETDEWEB)

    Fred Sabins

    2001-10-23

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). Work reported herein addresses tasks performed in the fourth quarter as well as the other three quarters of the past year. The subjects that were covered in previous reports and that are also discussed in this report include: Analysis of field laboratory data of active cement applications from three oil-well service companies; Preliminary findings from a literature review focusing on problems associated with ultra-lightweight cements; Summary of pertinent information from Russian ultra-lightweight cement literature review; and Comparison of compressive strengths of ULHS systems using ultrasonic and crush methods Results reported from the fourth quarter include laboratory testing of ULHS systems along with other lightweight cement systems--foamed and sodium silicate slurries. These comparison studies were completed for two different densities (10.0 and 11.5 lb/gal) and three different field application scenarios. Additional testing included the mechanical properties of ULHS systems and other lightweight systems. Studies were also performed to examine the effect that circulation by centrifugal pump during mixing has on breakage of ULHS.

  7. Lunar Dust Separation for Toxicology Studies

    Science.gov (United States)

    Cooper, Bonnie L.; McKay, D. S.; Riofrio, L. M.; Taylor, L. A.; Gonzalex, C. P.

    2010-01-01

    During the Apollo missions, crewmembers were briefly exposed to dust in the lunar module, brought in after extravehicular activity. When the lunar ascent module returned to micro-gravity, the dust that had settled on the floor now floated into the air, causing eye discomfort and occasional respiratory symptoms. Because our goal is to set an exposure standard for 6 months of episodic exposure to lunar dust for crew on the lunar surface, these brief exposures of a few days are not conclusive. Based on experience with industrial minerals such as sandblasting quartz, an exposure of several months may cause serious damage, while a short exposure may cause none. The detailed characteristics of sub-micrometer lunar dust are only poorly known, and this is the size range of particles that are of greatest concern. We have developed a method for extracting respirable dust (<2.5 micron) from Apollo lunar soils. This method meets stringent requirements that the soil must be kept dry, exposed only to pure nitrogen, and must conserve and recover the maximum amount of both respirable dust and coarser soil. In addition, we have developed a method for grinding coarser lunar soil to produce sufficient respirable soil for animal toxicity testing while preserving the freshly exposed grain surfaces in a pristine state.

  8. Foamed Cement Interactions with CO2

    Energy Technology Data Exchange (ETDEWEB)

    Verba, Circe [National Energy Technology Lab. (NETL), Albany, OR (United States); Montross, Scott [National Energy Technology Lab. (NETL), Albany, OR (United States). Oak Ridge Inst. for Science and Education (ORISE); Spaulding, Richard [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Dalton, Laura [National Energy Technology Lab. (NETL), Albany, OR (United States). Oak Ridge Inst. for Science and Education (ORISE); National Energy Technology Lab. (NETL), Morgantown, WV (United States); Crandall, Dustin [National Energy Technology Lab. (NETL), Morgantown, WV (United States); Moore, Jonathan [National Energy Technology Lab. (NETL), Morgantown, WV (United States); Glosser, Deborah [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Huerta, Nicolas [National Energy Technology Lab. (NETL), Albany, OR (United States); Kutchko, Barbara [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States)

    2017-01-23

    ultimately impacting the structural integrity of the wellbore. In this study, atmospheric foamed cements were generated using a neat cement and three foam qualities (volume of entrained gas in the cement) - 10%, 20%, and 30 % gas volume. The samples were immersed in a 0.25 M NaCl brine followed by the injection of supercritical CO2 at 28.9 MPa and 50°C. Petrophysical properties were examined for representative samples using computed tomography (CT) and scanning electron microscopy (SEM). CT scanning of representative samples across the range of reacted cements revealed macroscopic changes in structure due to brine/CO2/cement interactions. The high foam quality samples resulted in more CO2-saturated brine infiltrating radially deeper into the cement and thus were more susceptible to alteration. After 56 days of exposure, the 30% foam quality sample had the most reaction resulting in an alteration depth of 8.35 ± 0.13 mm with a calculated 34.6 ± 0.2% reacted area and 5.76 ± 0.2% reacted pore space area. The neat sample on the other hand, had a reaction depth of 0.31 ± 0.13 mm with a calculated 0.15 ± 0.08% reacted area and 0.57 ± 0.05% reacted pore area. Physical measurements of the exposed samples were consistent with this degree of alteration having 47.02% porosity and the highest permeability of 0.041 mD. These results indicate that the greater surface area provided by the increase of pore space in the higher quality foam coupled with carbonate diffusion reactions enabled greater alteration.

  9. PART II. HYDRATED CEMENTS

    Directory of Open Access Journals (Sweden)

    Milan Drabik

    2014-09-01

    Full Text Available Essential focus of the study has been to acquire thermoanalytical events, incl. enthalpies of decompositions - ΔH, of technological materials based on two types of Portland cements. The values of thermoanalytical events and also ΔH of probes of technological compositions, if related with the data of a choice of minerals of calcium-silicate-sulfate-aluminate hydrates, served as a valued input for the assessment of phases present and phase changes due to the topical hydraulic processes. The results indicate mainly the effects of "standard humidity" or "wet storage" of the entire hydration/hydraulic treatment, but also the presence of cement residues alongside calcium-silicate-sulfate-aluminate hydrates (during the tested period of treatment. "A diluting" effect of unhydrated cement residues upon the values of decomposition enthalpies in the studied multiphase system is postulated and discussed

  10. The mechanical effect of the existing cement mantle on the in-cement femoral revision.

    LENUS (Irish Health Repository)

    Keeling, Parnell

    2012-08-01

    Cement-in-cement revision hip arthroplasty is an increasingly popular technique to replace a loose femoral stem which retains much of the original cement mantle. However, some concern exists regarding the retention of the existing fatigued and aged cement in such cement-in-cement revisions. This study investigates whether leaving an existing fatigued and aged cement mantle degrades the mechanical performance of a cement-in-cement revision construct.

  11. Cement Mason's Curriculum. Instructional Units.

    Science.gov (United States)

    Hendirx, Laborn J.; Patton, Bob

    To assist cement mason instructors in providing comprehensive instruction to their students, this curriculum guide treats both the skills and information necessary for cement masons in commercial and industrial construction. Ten sections are included, as follow: related information, covering orientation, safety, the history of cement, and applying…

  12. Reducing cement's CO2 footprint

    Science.gov (United States)

    van Oss, Hendrik G.

    2011-01-01

    The manufacturing process for Portland cement causes high levels of greenhouse gas emissions. However, environmental impacts can be reduced by using more energy-efficient kilns and replacing fossil energy with alternative fuels. Although carbon capture and new cements with less CO2 emission are still in the experimental phase, all these innovations can help develop a cleaner cement industry.

  13. Cementing a wellbore using cementing material encapsulated in a shell

    Energy Technology Data Exchange (ETDEWEB)

    Aines, Roger D.; Bourcier, William L.; Duoss, Eric B.; Floyd, III, William C.; Spadaccini, Christopher M.; Vericella, John J.; Cowan, Kenneth Michael

    2017-03-14

    A system for cementing a wellbore penetrating an earth formation into which a pipe extends. A cement material is positioned in the space between the wellbore and the pipe by circulated capsules containing the cement material through the pipe into the space between the wellbore and the pipe. The capsules contain the cementing material encapsulated in a shell. The capsules are added to a fluid and the fluid with capsules is circulated through the pipe into the space between the wellbore and the pipe. The shell is breached once the capsules contain the cementing material are in position in the space between the wellbore and the pipe.

  14. Cementing a wellbore using cementing material encapsulated in a shell

    Science.gov (United States)

    Aines, Roger D.; Bourcier, William L.; Duoss, Eric B.; Spadaccini, Christopher M.; Cowan, Kenneth Michael

    2016-08-16

    A system for cementing a wellbore penetrating an earth formation into which a pipe extends. A cement material is positioned in the space between the wellbore and the pipe by circulated capsules containing the cement material through the pipe into the space between the wellbore and the pipe. The capsules contain the cementing material encapsulated in a shell. The capsules are added to a fluid and the fluid with capsules is circulated through the pipe into the space between the wellbore and the pipe. The shell is breached once the capsules contain the cementing material are in position in the space between the wellbore and the pipe.

  15. Technology Roadmaps: Cement

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    To support its roadmap work focusing on key technologies for emissions reductions, the International Energy Agency (IEA) also investigated one particular industry: cement. Cement production includes technologies that are both specific to this industry and those that are shared with other industries (e.g., grinding, fuel preparation, combustion, crushing, transport). An industry specific roadmap provides an effective mechanism to bring together several technology options. It outlines the potential for technological advancement for emissions reductions in one industry, as well as potential cross-industry collaboration.

  16. Cement og politik

    DEFF Research Database (Denmark)

    Lund, Joachim

    2012-01-01

    as well as in the public sphere. Most of the extensive job creating measures he carried out as a minister for public works necessarily involved the use of great amounts of cement – the primary produce of F.L. Smidth & Co. Gunnar Larsen thus became an easy target for Communist propaganda, picturing him...... of the Soviet Union (including an F.L. Smidth & Co. cement plant in former Estonia). He spent the last 15 months of the occupation in Sweden and was arrested after having returned to Copenhagen in May, 1945. Although a Copenhagen city court prison sentence for economic collaboration was reversed, he had...

  17. Novorossiysk agglomeration landscapes and cement production: geochemical impact assessment

    Science.gov (United States)

    Alekseenko, A. V.; Pashkevich, M. A.

    2016-09-01

    The article deals with assessing the environmental impact of marl mining and cement production in Novorossiysk city (Krasnodar krai, Russia). The existing methods of studying the environmental effects caused by the cement industry have been reviewed. Soil and aquatic vegetation sampling has been carried out and the gross concentration of metals in the samples has been defined. The research has been conducted in the certified and accredited laboratory using emission spectral analysis. The external control has been carried out via X-ray fluorescence analysis. Based on the collected data, main chemical pollutants in soil cover and water area near the cement plant have been identified. The contaminants released by urban enterprises and motor vehicle emissions, as well as fugitive dust from dumps and the cement factory, lead to multi-element lithogeochemical anomaly at geochemical barriers in soils. Accumulation of pollutants in soil depends on the type of land use and the area relief. The most contaminated aquatic landscapes have been identified in the inner bay. According to this information, the technical proposals can be prepared for environmental safety management in strongly polluted city areas, as well as for the reclamation design in the areas currently experiencing the negative impact of cement production.

  18. Perchlorate in dust fall and indoor dust in Malta: An effect of fireworks.

    Science.gov (United States)

    Vella, Alfred J; Chircop, Cynthia; Micallef, Tamara; Pace, Colette

    2015-07-15

    We report on the presence of perchlorate in the settleable dust of Malta, a small central Mediterranean island. Both dust fall collected directly as it precipitated from atmosphere over a period of one month and deposited indoor dust from domestic residences were studied. Perchlorate was determined by ion chromatography of water extracts of the collected dusts. Dust fall was collected from 43 towns during 2011 to 2013 and indoor dust was sampled from homes in the same localities. Perchlorate was detected in 108 of 153 samples of dust fall (71%) and in 28 of 37 indoor dust samples (76%). Detectable perchlorate in dust fall ranged from 0.52μgg(-1) to 561μgg(-1) with a median value of 6.2μgg(-1); in indoor dust, levels were from 0.79μgg(-1) to 53μgg(-1) with a median value of 7.8μgg(-1), the highest recorded anywhere to date. Statistical analysis suggested that there was no significant difference in perchlorate content of indoor dust and dust fall. Perchlorate levels in dust fall escalate during the summer in response to numerous religious feasts celebrated with fireworks and perchlorate persists at low μgg(-1) concentrations for several months beyond the summer festive period. In Malta, perchlorate derives exclusively from KClO4, imported for fireworks manufacture. Its residue in dust presents an exposure risk to the population, especially via ingestion by hand to mouth transfer. Our results suggest that wherever intensive burning of fireworks takes place, the environmental impact may be much longer lived than realised, mainly due to re-suspension and deposition of contaminated settled dust in the urban environment.

  19. Arthroscopic burring of exposed cement following curettage and cavity filling cementation for chondroblastoma of the proximal tibia.

    Science.gov (United States)

    Park, Jong-Hoon; Chae, In-Jung; Han, Seung-Beom; Lee, Dae-Hee

    2015-03-01

    Chondroblastoma of the proximal tibia is difficult to treat because of its epiphyseal predilection. This condition can be treated by curettage, which results in immediate restoration of stability and a reduced recurrence rate, followed by cement filling of the bone defect. Nevertheless, contact with cement can damage articular cartilage, potentially leading to severe knee osteoarthritis. Most previous reports regarding this complication described patients with giant cell tumors of the proximal tibia. We present here a patient who underwent arthroscopic treatment for cement exposure caused by articular cartilage loss of the tibial plateau, which occurred after initial curettage and cementation for chondroblastoma of the proximal tibia. To our knowledge, this is the first report on arthroscopic treatment of this condition.

  20. THE MEASUREMENT AND DISTRIBUTION OF WOOD DUST

    Directory of Open Access Journals (Sweden)

    Andrea Rosario Proto

    2010-03-01

    Full Text Available In Italy, the woodworking industry presents many issues in terms of occupational health and safety. This study on exposure to wood dust could contribute to the realization of a prevention model in order to limit exposure to carcinogenic agents to the worker. The sampling methodology illustrated the analysis of dust emissions from the woodworking machinery in operation throughout the various processing cycles. The quantitative and qualitative assessment of exposure was performed using two different methodologies. The levels of wood dust were determined according to EN indications and sampling was conducted using IOM and Cyclon personal samplers. The qualitative research of wood dust was performed using an advanced laser air particle counter. This allowed the number of particles present to be counted in real time. The results obtained allowed for an accurate assessment of the quality of the dust emitted inside the workplace during the various processing phases. The study highlighted the distribution of air particles within the different size classes, the exact number of both thin and ultra-thin dusts, and confirmed the high concentration of thin dust particles which can be very harmful to humans.

  1. Dust remobilization in fusion plasmas

    CERN Document Server

    Tolias, P; De Angeli, M; De Temmerman, G; Ripamonti, D; Riva, G; Bykov, I; Shalpegin, A; Vignitchouk, L; Brochard, F; Bystrov, K; Bardin, S; Litnovsky, A

    2016-01-01

    The first combined experimental and theoretical studies of dust remobilization by plasma forces are reported. The main theoretical aspects of remobilization are analyzed. In particular, the dominant role of adhesive forces is highlighted and generic remobilization conditions - detachment, sliding, rolling - are formulated. A novel experimental technique is proposed, based on controlled adhesion of dust grains on tungsten samples combined with detailed mapping of the dust deposition profile prior and post plasma exposure. Proof-of-principle experiments in the TEXTOR tokamak and the EXTRAP-T2R reversed-field pinch are presented. The versatile environment of the linear device Pilot-PSI allowed for experiments with different magnetic field topologies and varying plasma conditions that were complemented with camera observations.

  2. Osteotransductive bone cements.

    Science.gov (United States)

    Driessens, F C; Planell, J A; Boltong, M G; Khairoun, I; Ginebra, M P

    1998-01-01

    Calcium phosphate bone cements (CPBCs) are osteotransductive, i.e. after implantation in bone they are transformed into new bone tissue. Furthermore, due to the fact that they are mouldable, their osteointegration is immediate. Their chemistry has been established previously. Some CPBCs contain amorphous calcium phosphate (ACP) and set by a sol-gel transition. The others are crystalline and can give as the reaction product dicalcium phosphate dihydrate (DCPD), calcium-deficient hydroxyapatite (CDHA), carbonated apatite (CA) or hydroxyapatite (HA). Mixed-type gypsum-DCPD cements are also described. In vivo rates of osteotransduction vary as follows: gypsum-DCPD > DCPD > CDHA approximately CA > HA. The osteotransduction of CDHA-type cements may be increased by adding dicalcium phosphate anhydrous (DCP) and/or CaCO3 to the cement powder. CPBCs can be used for healing of bone defects, bone augmentation and bone reconstruction. Incorporation of drugs like antibiotics and bone morphogenetic protein is envisaged. Load-bearing applications are allowed for CHDA-type, CA-type and HA-type CPBCs as they have a higher compressive strength than human trabecular bone (10 MPa).

  3. Modeling Respiratory Toxicity of Authentic Lunar Dust

    Science.gov (United States)

    Santana, Patricia A.; James, John T.; Lam, Chiu-Wing

    2010-01-01

    The lunar expeditions of the Apollo operations from the 60 s and early 70 s have generated awareness about lunar dust exposures and their implication towards future lunar explorations. Critical analyses on the reports from the Apollo crew members suggest that lunar dust is a mild respiratory and ocular irritant. Currently, NASA s space toxicology group is functioning with the Lunar Airborne Dust Toxicity Assessment Group (LADTAG) and the National Institute for Occupational Safety and Health (NIOSH) to investigate and examine toxic effects to the respiratory system of rats in order to establish permissible exposure levels (PELs) for human exposure to lunar dust. In collaboration with the space toxicology group, LADTAG and NIOSH the goal of the present research is to analyze dose-response curves from rat exposures seven and twenty-eight days after intrapharyngeal instillations, and model the response using BenchMark Dose Software (BMDS) from the Environmental Protection Agency (EPA). Via this analysis, the relative toxicities of three types of Apollo 14 lunar dust samples and two control dust samples, titanium dioxide (TiO2) and quartz will be determined. This will be executed for several toxicity endpoints such as cell counts and biochemical markers in bronchoaveolar lavage fluid (BALF) harvested from the rats.

  4. Assessing the bioavailability and risk from metal-contaminated soils and dusts

    Science.gov (United States)

    Exposure to contaminated soil and dust is an important pathway in human health risk assessment. Physical and chemical characteristics, as well as biological factors, determine the bioaccessibility/bioavailability of soil and dust contaminants. Within a single sample, contaminat...

  5. Organophosphate esters in dust samples collected from Danish homes and daycare centers

    DEFF Research Database (Denmark)

    Langer, Sarka; Fredricsson, Malin; Weschler, Charles J.

    2016-01-01

    distribution of organophosphates in indoor dust is quite variable, with higher concentrations in industrialized countries. This trend differs from that for phthalate esters, whose geographic distribution is more homogeneous. Exposure to organophosphates via dust ingestion is relatively low, although...

  6. Corrosion of steel bars in cracked concrete made with ordinary portland, slag and fly ash cements

    Energy Technology Data Exchange (ETDEWEB)

    Mohammed, T.U.; Yamaji, T.; Hamada, H. [Port and Harbor Research Inst., Ministry of Land, Infrastructure and Transport (Japan); Aoyama, T. [PS Corp. (Japan)

    2001-07-01

    A study was conducted in which the marine durability of ordinary portland cement, slag and fly ash cement was examined using 15 year old plain and reinforced concrete cylindrical specimens. The performance of these cements was then examined for pre-cracked reinforced concrete prism samples. The process of manufacturing cement emits huge amounts of carbon dioxide into the global atmosphere. Replacing a portion of the cement with by-products from the steel industry and thermal power plants (which are both huge emitters of carbon dioxide) can lower carbon dioxide emissions and also solve the disposal issue of slag and fly ash while increasing the long-term durability of concrete structures. In this study, concrete cylindrical specimens were made of ordinary portland cement, slag and fly ash cements. The specimens were 100 x 100 x 600 mm prisms of different types of cement. Water-to-cement ratios were 0.45 and 0.55. Both tap water and seawater were used as mixing water. The samples were exposed in tidal pools for 15 years to evaluate the compressive strength of the concrete, corrosion of the steel bars, and chloride-ion concentrations in the concrete. It was shown that, with the exception of fly ash cements, the compressive strength of most cements increased after 15 years of exposure compared to its 28 day strength. Type C slag cement demonstrated the best performance against chloride-ion at the surface of concrete made with slag and fly ash. Voids in the steel-concrete interface make it possible for corrosion pits to develop. The use of seawater as mixing water results in earlier strength development at 28 days and does not cause to the strength of the concrete to regress after 15-years of exposure, but it causes more corrosion of steel bars at a lower cover depth. Corrosion of steel bars is not an issue at deeper cover depths. 15 refs., 19 tabs., 13 figs.

  7. Mineral resource of the month: hydraulic cement

    Science.gov (United States)

    van Oss, Hendrik G.

    2012-01-01

    Hydraulic cements are the binders in concrete and most mortars and stuccos. Concrete, particularly the reinforced variety, is the most versatile of all construction materials, and most of the hydraulic cement produced worldwide is portland cement or similar cements that have portland cement as a basis, such as blended cements and masonry cements. Cement typically makes up less than 15 percent of the concrete mix; most of the rest is aggregates. Not counting the weight of reinforcing media, 1 ton of cement will typically yield about 8 tons of concrete.

  8. Cement from magnesium substituted hydroxyapatite.

    Science.gov (United States)

    Lilley, K J; Gbureck, U; Knowles, J C; Farrar, D F; Barralet, J E

    2005-05-01

    Brushite cement may be used as a bone graft material and is more soluble than apatite in physiological conditions. Consequently it is considerably more resorbable in vivo than apatite forming cements. Brushite cement formation has previously been reported by our group following the mixture of nanocrystalline hydroxyapatite and phosphoric acid. In this study, brushite cement was formed from the reaction of nanocrystalline magnesium-substituted hydroxyapatite with phosphoric acid in an attempt to produce a magnesium substituted brushite cement. The presence of magnesium was shown to have a strong effect on cement composition and strength. Additionally the presence of magnesium in brushite cement was found to reduce the extent of brushite hydrolysis resulting in the formation of HA. By incorporating magnesium ions in the apatite reactant structure the concentration of magnesium ions in the liquid phase of the cement was controlled by the dissolution rate of the apatite. This approach may be used to supply other ions to cement systems during setting as a means to manipulate the clinical performance and characteristics of brushite cements.

  9. POZZOLAN AND CEMENTS WITH POZZOLAN

    Directory of Open Access Journals (Sweden)

    Hasan KAPLAN

    1995-02-01

    Full Text Available Cement, one of the basic material of construction engineering, has an important place in view of strength and cost of structures. Cement consumption is increasing parallel to development of building construction sector. For cement producers, minimal cost is desired by using new and economical material sources. On the other hand, the controllers and contractors need cheaper, safer and higher strength materials. From this respect cement industry tends to use cement with pozzolan. In Türkiye, cement with pozzolan is produced by adding the pozzolan, which has a large reservoir in the country, in cement in sertain amount. However this type of cement is consumed in the construction sector, sortage of scientific investigation and speculative news on the subject.are worried the users and producers. In this paper, prior to an experimental study on the cements having pozzolan additive, historical development of pozzolan, reservoir of Turkiye, and comparison with portland cement is carried out. Advantages and disadvantages of pozzolan are also discussed in some points.

  10. Minimally invasive maxillofacial vertical bone augmentation using brushite based cements.

    Science.gov (United States)

    Tamimi, Faleh; Torres, Jesus; Lopez-Cabarcos, Enrique; Bassett, David C; Habibovic, Pamela; Luceron, Elena; Barralet, Jake E

    2009-01-01

    An ideal material for maxillofacial vertical bone augmentation procedures should not only be osteoconductive, biocompatible and mechanically strong, but should also be applied using minimally invasive procedures and remain stable with respect to the original bone surfaces. This way, implant exposure and infection might be reduced and good mechanical stability may be achieved. Calcium phosphate cements are proven biocompatible and osteoconductive materials that can be injected using minimally invasive procedures. Among these cements, brushite based cements have the added advantage of being biodegradable in vivo. Therefore, this material has the potential for use in the aforementioned procedures. An in vivo study was performed in rabbits to evaluate the potential use of brushite cements in minimally invasive maxillofacial vertical bone augmentation procedures. In this study, we injected self-setting brushite cements on the subperiosteal bone surface using a minimally invasive tunnelling technique. The cement pastes were stable on the bone surface and hardened soon after they were injected thereby negating the need for additional supports such as membranes or meshes. The animals were sacrificed 8 weeks after the intervention and histological observations revealed signs of successful vertical bone augmentation. Therefore, we have demonstrated a minimally invasive vertical bone augmentation procedure that is an attractive alternative to current surgical procedures in terms of increased simplicity, reduced trauma, and lower cost of surgery.

  11. Coal acid mine drainage treatment using cement kiln dust

    Directory of Open Access Journals (Sweden)

    Edgar Alberto Martínez

    2014-01-01

    Full Text Available Los sulfuros están presentes en distintas rocas. Durante las actividades mineras y el proceso de remoción de sulfuros se pueden producir Drenajes Ácidos de Minería (DAM, con iones de sulfato (SO4-2. Los DAMs son fuente de polución en las actividades mineras y en Colombia su descarga en los cuerpos de agua debe cumplir las regulaciones nacionales (pH entre 5 y 9. Polvo de horno cementero (CKD, con carbonato de calcio principalmente, de una planta de Cementos Argos S.A. fue usado para neutralizar un DAM generado en la biodesulfurización de carbón. Los DAMs neutralizados tuvieron pHs entre 7,72 y 8,05 y la eliminación de sulfatos entre 67% a 70%. El precipitado se secó y analizó para determinar su composición química y mineralógica. Se encontró humedad entre 69% y 81%; yeso con un 50% de pureza aproximadamente y carbonato de calcio. Esta composición lo hace adecuado para uso en la producción de cemento.

  12. US cement industry

    Energy Technology Data Exchange (ETDEWEB)

    Nisbet, M.A.

    1997-12-31

    This paper describes the cement and concrete industry, and provides data on energy use and carbon dioxide emissions. The potential impact of an energy tax on the industry is briefly assessed. Opportunities identified for reducing carbon dioxide emissions include improved energy efficiency, alternative fuels, and alternative materials. The key factor in determining CO{sub 2} emissions is the level of domestic production. The projected improvement in energy efficiency and the relatively slow growth in domestic shipments indicate that CO{sub 2} emissions in 2000 should be about 5% above the 1990 target. However, due to the cyclical nature of cement demand, emissions will probably be above target levels during peak demand and below target levels during demand troughs. 7 figs., 2 tabs.

  13. Random ionic mobility on blended cements exposed to aggressive environments

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Rosario, E-mail: rosario.garcia@uam.es [Departamento de Geologia y Geoquimica, Facultad de Ciencias, Universidad Autonoma, 28049 Madrid (Spain); Rubio, Virginia [Departamento de Geografia, Facultad de Filosofia y Letras, Universidad Autonoma, 28049 Madrid (Spain); Vegas, Inigo [Labein-Tecnalia, 48160 Derio, Vizcaya (Spain); Frias, Moises [Instituto Eduardo Torroja, CSIC, c/ Serrano Galvache, 4, 28033 Madrid (Spain)

    2009-09-15

    It is known that the partial replacement of cement by pozzolanic admixtures generally leads to modifications in the diffusion rates of harmful ions. Recent research has centred on obtaining new pozzolanic materials from industrial waste and industrial by-products and on the way that such products can influence the performance of blended cements. This paper reports the behaviour of cements blended with calcined paper sludge (CPS) admixtures under exposure to two different field conditions: sea water and cyclic changes in temperature and humidity. Cement mortars were prepared with 0% and 10% paper sludge calcined at 700 deg. C. The penetration of ions within the microstructure of cement matrices was studied using X-ray diffraction (XRD) and scanning electron microscopy equipped with an energy dispersive X-ray analyser (SEM/EDX) analytical techniques. The results show that ionic mobility varies substantially according to the type of exposure and the presence of the calcined paper sludge. The incorporation of 10% CPS is shown to assist the retention and diffusion of the ions.

  14. Imaging-based dust sensors: equipment and methods

    Science.gov (United States)

    Bonifazi, Giuseppe; Greco, Sonia

    2004-05-01

    Dust detection and control in real time, represent one of the most challenging problem in all those environments where fine and ultrafine airborne particulate solids products are present. The presence of such products can be linked to several factors, often directly related and influenced by the working-production actions performed. Independently from the causes generating dust, airborne contaminants are an occupational problem of increasing interest as they are related to a wide number of diseases. In particular, airborne dusts are well known to be associated with several classical occupational lung diseases, such as the pneumoconiosis, especially at high levels of exposure. Nowadays there is also an increasing interest in other dust related diseases, from the most serious as cancer and asthma, to those related with allergies or irritation and other illnesses, also occurring at lower levels of exposure. Among the different critical factors influencing health risk for airborne dust exposure, mainly four have to be considered, that is: i) nature of the dust resulting from working in terms of presence of specific poisoning material, i.e. free silica, and morphological and morphometrical attributes of particulates constituting airborne dust; ii) size of the particles, iii) duration of exposure time and, finally, iv) airborne dust concentration in the breathing zone where the worker performs his activity. A correct dust detection is not easy, especially if some of the previous mentioned factors, have to be detected and quantified in real time in order to define specific "on-line" control actions aimed to reduce the level of the exposure to dust of the workers, as for example: i) modification of aspirating devices operating condition, change of filtering cleaning sequence, etc. . The more severe are the environmental conditions, in terms of dust presence (in quantity and quality) more difficult is to utilize efficient sampling devices. Detection devices, in fact, tend

  15. Advances in Glass Ionomer Cements

    OpenAIRE

    KAYA, Dt. Tuğba; TİRALİ, Yard. Doç. Dr. Resmiye Ebru

    2013-01-01

    In recent years there have been a number of innovations and developments with respect to glass ionomer cements and their applications in clinical dentistry. This article considers some of the recent outstanding studies regarding the field of glass ionomer cement applications, adhesion and setting mechanisms, types, advantage and disadvantages among themselves and also to enhance the physical and antibacterial properties under the title of 'Advances in Glass Ionomer Cements'. As their biologic...

  16. Cement penetration after patella venting.

    Science.gov (United States)

    Jones, Christopher W; Lam, Li-On; Butler, Adam; Wood, David J; Walsh, William R

    2009-01-01

    There is a high rate of patellofemoral complications following total knee arthroplasty. Optimization of the cement-bone interface by venting and suction of the tibial plateau has been shown to improve cement penetration. Our study was designed to investigate if venting the patella prior to cementing improved cement penetration. Ten paired cadaver patellae were allocated prior to resurfacing to be vented or non-vented. Bone mineral density (BMD) was measured by DEXA scanning. In vented specimens, a 1.6 mm Kirschner wire was used to breach the anterior cortex at the center. Specimens were resurfaced with standard Profix instrumentation and Versabond bone cement (Smith and Nephew PLC, UK). Cement penetration was assessed from Faxitron and sectioned images by a digital image software package (ImageJ V1.38, NIH, USA). Wilcoxon rank sum test was used to assess the difference in cement penetration between groups. The relationship between BMD and cement penetration was analyzed by Pearson correlation coefficient. There was a strong negative correlation between peak BMD and cement penetration when analyzed independent of experimental grouping (r(2)=-0.812, p=0.004). Wilcoxon rank sum testing demonstrated no significant difference (rank sum statistic W=27, p=0.579) in cement penetration between vented (10.53%+/-4.66; mean+/-std dev) and non-vented patellae (11.51%+/-6.23; mean+/-std dev). Venting the patella using a Kirschner wire does not have a significant effect on the amount of cement penetration achieved in vitro using Profix instrumentation and Versabond cement.

  17. Dust Studies in DIII-D and TEXTOR

    Energy Technology Data Exchange (ETDEWEB)

    Rudakov, D L; Litnovsky, A; West, W P; Yu, J H; Boedo, J A; Bray, B D; Brezinsek, S; Brooks, N H; Fenstermacher, M E; Groth, M; Hollmann, E M; Huber, A; Hyatt, A W; Krasheninnikov, S I; Lasnier, C J; Moyer, R A; Pigarov, A Y; Philipps, V; Pospieszczyk, A; Smirnov, R D; Sharpe, J P; Solomon, W M; Watkins, J G; Wong, C C

    2009-02-17

    Studies of naturally occurring and artificially introduced carbon dust are conducted in DIII-D and TEXTOR. In DIII-D, dust does not present operational concerns except immediately after entry vents. Submicron sized dust is routinely observed using Mie scattering from a Nd:Yag laser. The source is strongly correlated with the presence of Type I edge localized modes (ELMs). Larger size (0.005-1 mm diameter) dust is observed by optical imaging, showing elevated dust levels after entry vents. Inverse dependence of the dust velocity on the inferred dust size is found from the imaging data. Direct heating of the dust particles by the neutral beam injection (NBI) and acceleration of dust particles by the plasma flows are observed. Energetic plasma disruptions produce significant amounts of dust. Large flakes or debris falling into the plasma may result in a disruption. Migration of pre-characterized carbon dust is studied in DIII-D and TEXTOR by introducing micron-size dust in plasma discharges. In DIII-D, a sample holder filled with {approx}30 mg of dust is introduced in the lower divertor and exposed to high-power ELMing H-mode discharges with strike points swept across the divertor floor. After a brief exposure ({approx}0.1 s) at the outer strike point, part of the dust is injected into the plasma, raising the core carbon density by a factor of 2-3 and resulting in a twofold increase of the radiated power. In TEXTOR, instrumented dust holders with 1-45 mg of dust are exposed in the scrape-off layer 0-2 cm radially outside of the last closed flux surface in discharges heated with neutral beam injection (NBI) power of 1.4 MW. At the given configuration of the launch, the dust did not penetrate the core plasma and only moderately perturbed the edge plasma, as evidenced by an increase of the edge carbon content.

  18. Compacting of fly dusts from cupola and electric arc furnace

    Directory of Open Access Journals (Sweden)

    D. Baricová

    2012-01-01

    Full Text Available Recycling and utilization of dust waste is important not only from the point of view of its usage as an alternative source of raw materials, but regarding the environmental problems also. Dust emissions arise from thermal and chemical or physical processes and mechanical actions. Two kinds of fl y dusts from cupola furnaces (hot and cold blast cupola furnace and fl y dust from electric arc furnace were used by experiments. They were pelletized only with addition of water and briquetted with diff erent addition of water glass, bentonite and cement. Quality of briquettes was tested by compression – strength test and by break down test in green state, after drying and afterstoring (1 month.

  19. OCCUPATIONAL EXPOSURE AND COPD

    DEFF Research Database (Denmark)

    Würtz, Else Toft

    Chronic Obstructive Pulmonary Disease (COPD) is a common disease. The main risk factor is smoking although 15% of the COPD cases are expected to be preventable if the occupational exposures from vapour, gas, dust, and fume were eliminated; the population attributable fraction (PAF). The thesis...... addresses the association between occupational exposure and COPD in a population-based cohort of Danes aged 45-84-years. 4717 participants were included at baseline and 2624 at the four year follow-up. COPD was defined by spirometry and the occupational exposure was based on specialist defined jobs...... and questionnaires. The main occupational exposure was organic dust and 49% reported no lifetime occupational exposure. The results suggest occupational exposures to be associated to COPD also in never smokers and women. We found an exposure-response relation in the cross sectional analyses. The results...

  20. Simulation tests to assess occupational exposure to airborne asbestos from artificially weathered asphalt-based roofing products.

    Science.gov (United States)

    Sheehan, Patrick; Mowat, Fionna; Weidling, Ryan; Floyd, Mark

    2010-11-01

    Historically, asbestos-containing roof cements and coatings were widely used for patching and repairing leaks. Although fiber releases from these materials when newly applied have been studied, there are virtually no useful data on airborne asbestos fiber concentrations associated with the repair or removal of weathered roof coatings and cements, as most studies involve complete tear-out of old roofs, rather than only limited removal of the roof coating or cement during a repair job. This study was undertaken to estimate potential chrysotile asbestos fiber exposures specific to these types of roofing products following artificially enhanced weathering. Roof panels coated with plastic roof cement and fibered roof coating were subjected to intense solar radiation and daily simulated precipitation events for 1 year and then scraped to remove the weathered materials to assess chrysotile fiber release and potential worker exposures. Analysis of measured fiber concentrations for hand scraping of the weathered products showed 8-h time-weighted average concentrations that were well below the current Occupational Safety and Health Administration permissible exposure limit for asbestos. There was, however, visibly more dust and a few more fibers collected during the hand scraping of weathered products compared to the cured products previously tested. There was a notable difference between fibers released from weathered and cured roofing products. In weathered samples, a large fraction of chrysotile fibers contained low concentrations of or essentially no magnesium and did not meet the spectral, mineralogical, or morphological definitions of chrysotile asbestos. The extent of magnesium leaching from chrysotile fibers is of interest because several researchers have reported that magnesium-depleted chrysotile fibers are less toxic and produce fewer mesothelial tumors in animal studies than normal chrysotile fibers.

  1. Thermal Shock-resistant Cement

    Energy Technology Data Exchange (ETDEWEB)

    Sugama T.; Pyatina, T.; Gill, S.

    2012-02-01

    We studied the effectiveness of sodium silicate-activated Class F fly ash in improving the thermal shock resistance and in extending the onset of hydration of Secar #80 refractory cement. When the dry mix cement, consisting of Secar #80, Class F fly ash, and sodium silicate, came in contact with water, NaOH derived from the dissolution of sodium silicate preferentially reacted with Class F fly ash, rather than the #80, to dissociate silicate anions from Class F fly ash. Then, these dissociated silicate ions delayed significantly the hydration of #80 possessing a rapid setting behavior. We undertook a multiple heating -water cooling quenching-cycle test to evaluate the cement’s resistance to thermal shock. In one cycle, we heated the 200 and #61616;C-autoclaved cement at 500 and #61616;C for 24 hours, and then the heated cement was rapidly immersed in water at 25 and #61616;C. This cycle was repeated five times. The phase composition of the autoclaved #80/Class F fly ash blend cements comprised four crystalline hydration products, boehmite, katoite, hydrogrossular, and hydroxysodalite, responsible for strengthening cement. After a test of 5-cycle heat-water quenching, we observed three crystalline phase-transformations in this autoclaved cement: boehmite and #61614; and #61543;-Al2O3, katoite and #61614; calcite, and hydroxysodalite and #61614; carbonated sodalite. Among those, the hydroxysodalite and #61614; carbonated sodalite transformation not only played a pivotal role in densifying the cementitious structure and in sustaining the original compressive strength developed after autoclaving, but also offered an improved resistance of the #80 cement to thermal shock. In contrast, autoclaved Class G well cement with and without Class F fly ash and quartz flour failed this cycle test, generating multiple cracks in the cement. The major reason for such impairment was the hydration of lime derived from the dehydroxylation of portlandite formed in the autoclaved

  2. Phosphate based oil well cements

    Science.gov (United States)

    Natarajan, Ramkumar

    The main application of the cement in an oil well is to stabilize the steel casing in the borehole and protect it from corrosion. The cement is pumped through the borehole and is pushed upwards through the annulus between the casing and the formation. The cement will be exposed to temperature and pressure gradients of the borehole. Modified Portland cement that is being used presently has several shortcomings for borehole sealant. The setting of the Portland cement in permafrost regions is poor because the water in it will freeze even before the cement sets and because of high porosity and calcium oxide, a major ingredient it gets easily affected by the down hole gases such as carbon dioxide. The concept of phosphate bonded cements was born out of considerable work at Argonne National Laboratory (ANL) on their use in stabilization of radioactive and hazardous wastes. Novel cements were synthesized by an acid base reaction between a metal oxide and acid phosphate solution. The major objective of this research is to develop phosphate based oil well cements. We have used thermodynamics along with solution chemistry principles to select calcined magnesium oxide as candidate metal oxide for temperatures up to 200°F (93.3°C) and alumina for temperatures greater than 200°F (93.3°C). Solution chemistry helped us in selecting mono potassium phosphate as the acid component for temperatures less than 200°F (93.3°C) and phosphoric acid solution greater than 200°F (93.3°C). These phosphate cements have performance superior to common Portland well cements in providing suitable thickening time, better mechanical and physical properties.

  3. Research by NIOSH for controlling respirable dust and methane gas on continuous miner faces

    Energy Technology Data Exchange (ETDEWEB)

    Goodman, G.V.R.; Taylor, C.D.; Colinet, J.F.; Thimons, E.D. [National Institute for Occupational Safety and Health, Pittsburgh, PA (USA). Pittsburgh Research Laboratory, Dust and Toxic Substances Control Branch

    2001-07-01

    The importance of controlling respirable dust and methane gas levels in underground coal mining cannot be underestimated. While respirable dust can significantly affect the occupational health of underground coal miners, methane gas accumulations pose significant safety concerns for these same workers. Water sprays and machine mounted dust scrubbers offer effective control of respirable dust exposures and methane gas accumulations. Water must not only be applied carefully to avoid dust rollback to the machine operator but must create sufficient turbulence to remove dead zones that could contain high concentrations of methane gas. While the flooded-bed dust scrubber has been generally responsible for decreased worker exposures to respirable dusts, this device has proved effective in controlling methane levels at the face. This paper reviews practical applications of water sprays and dust scrubbers to control respirable dust and methane gas on continuous miner faces. 15 refs., 6 figs.

  4. Deconstruction of the asbestos cement roof of the central market in Alicante difficulties in the practical application of RD 396/2006 (works with risk of exposure to asbestos); Deconstruccion de la cubierta de asbesto-cemento del Mercado Central de Abastos de Alicante. Dificultades en la aplicacion practica del RD 396/2006 (trabajos con riesgo de exposicion al amianto)

    Energy Technology Data Exchange (ETDEWEB)

    Sirvent Perez, C. D.

    2010-07-01

    The project and the works described below mainly deal with the deconstruction of the current asbestos-cement roof of the Central Market in Alicante in order to replace it with another roof of zinc diamond scales, similar to the original which was implementation in 1921 when the building went into service. These works were necessary to avoid the causes (and consequences) that generate the appearance of rainwater infiltration, as was described in an earlier report that was done in 2006, also drafted by the undersigned technicians. The article shows the difficulty of the practical application of RD 396/2006 (minimum health and safety requirements for works with risks of exposure to asbestos) in a case of a certain complexity such as this, especially in areas such as economic (rising costs), technical (increasing difficulty of implementation), and the total duration of the work (total time extension due to interference with other trades). (Author) 14 refs.

  5. Rubberwood dust and lung function among Thai furniture factory workers.

    Science.gov (United States)

    Thetkathuek, Anamai; Yingratanasuk, Tanongsak; Demers, Paul A; Thepaksorn, Phayong; Saowakhontha, Sastri; Keifer, Matthew C

    2010-01-01

    The objective of this study was to assess factors affecting lung function among 685 workers in the rubberwood (Hevea brasiliensis) furniture industry in the Chonburi and Rayung provinces of eastern Thailand. Study data were gathered using questionnaires, by sampling wood dust, and by spirometry. The mean wood dust exposure level in the factories was 4.08 mg/m3 (SD = 1.42, range: 1.15-11.17 mg/m3). The mean overall percent of predicted forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and FEV1/FVC values were 84 % (SD = 13.41), 86 % (SD = 14.40), and 99% (SD = 10.42), respectively. Significant negative correlations were found between mean dust exposure levels and FVC (p = 0.0008), and FEV1/FVC% (p lung function and wood dust levels among wood workers suggests that rubberwood dust exposure negatively affects lung function.

  6. Occurrence and human exposure of p-hydroxybenzoic acid esters (parabens), bisphenol A diglycidyl ether (BADGE), and their hydrolysis products in indoor dust from the United States and three East Asian countries.

    Science.gov (United States)

    Wang, Lei; Liao, Chunyang; Liu, Fang; Wu, Qian; Guo, Ying; Moon, Hyo-Bang; Nakata, Haruhiko; Kannan, Kurunthachalam

    2012-11-06

    p-Hydroxybenzoic acid esters (parabens) and bisphenol A diglycidyl ether (BADGE) are widely present in personal care products, food packages, and material coatings. Nevertheless, little is known about the occurrence of these compounds in indoor dust. In this study, we collected 158 indoor dust samples from the U.S., China, Korea, and Japan and determined the concentrations of 11 target chemicals, viz., six parabens and their common hydrolysis product, 4-hydroxybenzoic acid (4-HB), as well as BADGE and its three hydrolysis products (BADGE·H(2)O, BADGE·2H(2)O, and BADGE·HCl·H(2)O). All of the target compounds were found in dust samples from four countries. Concentrations of sum of six parabens in dust were on the order of several hundred to several thousands of nanogram per gram. Geometric mean concentrations of BADGEs in dust ranged from 1300 to 2890 ng/g among four countries. Methyl paraben (MeP), propyl paraben (PrP), BADGE·2H(2)O, and BADGE·HCl·H(2)O were the predominant compounds found in dust samples. This is the first report of BADGE and its hydrolysis products (BADGEs) in indoor dust samples and of parabens in indoor dust from Asian countries. On the basis of the measured concentrations of target chemicals, we estimated the daily intake (EDI) via dust ingestion. The EDIs of parabens via dust ingestion were 5-10 times higher in children than in adults. Among the four countries studied, the EDIs of parabens (5.4 ng/kg-bw/day) and BADGEs (6.5 ng/kg-bw/day) through dust ingestion were the highest for children in Korea and Japan.

  7. Crystalline silica dust and respirable particulate matter during indoor concrete grinding - wet grinding and ventilated grinding compared with uncontrolled conventional grinding.

    Science.gov (United States)

    Akbar-Khanzadeh, Farhang; Milz, Sheryl; Ames, April; Susi, Pamela P; Bisesi, Michael; Khuder, Sadik A; Akbar-Khanzadeh, Mahboubeh

    2007-10-01

    The effectiveness of wet grinding (wet dust reduction method) and ventilated grinding (local exhaust ventilation method, LEV) in reducing the levels of respirable crystalline silica dust (quartz) and respirable suspended particulate matter (RSP) were compared with that of uncontrolled (no dust reduction method) conventional grinding. A field laboratory was set up to simulate concrete surface grinding using hand-held angle grinders in an enclosed workplace. A total of 34 personal samples (16 pairs side-by-side and 2 singles) and 5 background air samples were collected during 18 concrete grinding sessions ranging from 15-93 min. General ventilation had no statistically significant effect on operator's exposure to dust. Overall, the arithmetic mean concentrations of respirable crystalline silica dust and RSP in personal air samples during: (i) five sessions of uncontrolled conventional grinding were respectively 61.7 and 611 mg/m(3) (ii) seven sessions of wet grinding were 0.896 and 11.9 mg/m(3) and (iii) six sessions of LEV grinding were 0.155 and 1.99 mg/m(3). Uncontrolled conventional grinding generated relatively high levels of respirable silica dust and proportionally high levels of RSP. Wet grinding was effective in reducing the geometric mean concentrations of respirable silica dust 98.2% and RSP 97.6%. LEV grinding was even more effective and reduced the geometric mean concentrations of respirable silica dust 99.7% and RSP 99.6%. Nevertheless, the average level of respirable silica dust (i) during wet grinding was 0.959 mg/m(3) (38 times the American Conference of Governmental Industrial Hygienists [ACGIH] threshold limit value [TLV] of 0.025 mg/m(3)) and (ii) during LEV grinding was 0.155 mg/m(3) (6 times the ACGIH TLV). Further studies are needed to examine the effectiveness of a greater variety of models, types, and sizes of grinders on different types of cement in different positions and also to test the simulated field lab experimentation in the field.

  8. X线胸片异常与粉尘暴露、吸烟、工龄等因素的相关性研究%Correlation study between dust exposures, smoking length of service and other factors and chest X-ray abnormalities

    Institute of Scientific and Technical Information of China (English)

    杨慧; 游志容; 梁海荣; 翟璐; 邵军丽; 唐焕文

    2013-01-01

    目的 了解石材加工工人粉尘暴露、吸烟、工龄等因素对X线胸片异常的影响,为预防该行业相关疾病的发生提供参考依据.方法 采用以医院放射科进行X线胸片检查的人员为基础的病例对照研究,病例组为胸片异常的396例病人,对照组为同期没有胸片异常的538例健康体检者.对石材加工所涉及工种的环境用滤膜称重法和滤膜溶解涂片法分别进行总粉尘浓度和粉尘分散度的测定.结果 对照组和病例组粉尘暴露情况差异有显著性[x2=22.32,P<0.05,OR=5.17,95%CI为(2.44,10.91)];抽检的石材加工厂中各工种环境的总粉尘浓度和分散度均符合GBZ2-2002限值的要求.粉尘暴露对X线胸片有影响,危险度随粉尘暴露而增加.吸烟和工龄是胸片异常的危险因素(x2=15.83,4.74; P<0.05);工种对X线胸片异常无显著影响.结论 石材加工工人X线胸片异常与粉尘暴露、吸烟、工龄相关,与工种无关.%Objective To understand the impact of stone processing workers' dust exposures,smoking,length of service and other factors on the chest X-ray abnormalities,and provide a reference for the prevention for the occurrence of related diseases in the industry.Methods A case control study was conducted.396 patients with chest X-ray abnormalities and 538 personnel without chest X-ray abnormalities in the same period as healthy subjects were enrolled.The total dust concentration and dust dispersity of stone processing environment were detected by the membrane filter weighing methods and the membrane filter dissolved smear methods.Results Dust exposures of the control group and the case group were statistically significant,X 2=22.32,p<0.05,OR=5.17,95%CI( 2.44,10.91 ).The total dust concentration and dust dispersity of the stone processing in different work environment were consistent with ( GBZ 2-2002)limit requirements.Dust exposures had an effect on X-ray chest radiograph,and the risk increasd with the

  9. Distribution of polybrominated diphenyl ethers and dust particle size fractions adherent to skin in indoor dust, Pretoria, South Africa.

    Science.gov (United States)

    Kefeni, Kebede Keterew; Okonkwo, Jonathan O

    2014-03-01

    In order to determine human exposure to the indoor toxicant, selection of dust fraction and understanding dust particle size distribution in settled indoor dust are very important. This study examined the influence of dust particle size on the concentration of polybrominated diphenyl ethers (PBDEs) congeners, assessed the distribution of dust particle size and characterized the main indoor emission sources of PBDEs. Accordingly, the concentrations of PBDE congeners determined in different indoor dust fractions were found to be relatively higher in the order of dust particle size: 45-106 μm>(106-150 μm. The finding shows arbitrary selection of dust fractions for exposure determination may result in wrong conclusions. Statistically significant moderate correlation between the concentration of Σ9PBDEs and organic matter content calculated with respect to the total dust mass was also observed (r=0.55, p=0.001). On average, of total dust particle size <250 μm, 93.4 % (m/m%) of dust fractions was associated with less than 150 μm. Furthermore, of skin adherent dust fractions considered (<150 μm), 86 % (v/v%) is in the range of particle size 9.25-104.7 μm. Electronic materials treated with PBDEs were found the main emission sources of PBDE congeners in indoor environment. Based on concentrations of PBDEs determined and mass of indoor dust observed, 150 μm metallic sieve is adequate for human exposure risk assessment. However, research in this area is very limited and more research is required to generalize the fact.

  10. Microwave assisted preparation of magnesium phosphate cement (MPC) for orthopedic applications: A novel solution to the exothermicity problem

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Huan, E-mail: Huan.Zhou@rockets.utoledo.edu [Department of Mechanical, Industrial and Manufacturing Engineering, The University of Toledo, Toledo, OH 43606 (United States); Agarwal, Anand K.; Goel, Vijay K. [Department of Bioengineering, The University of Toledo, Toledo, OH 43606 (United States); Bhaduri, Sarit B. [Department of Mechanical, Industrial and Manufacturing Engineering, The University of Toledo, Toledo, OH 43606 (United States); Division of Dentistry, The University of Toledo, Toledo, OH 43606 (United States)

    2013-10-15

    There are two interesting features of this paper. First, we report herein a novel microwave assisted technique to prepare phosphate based orthopedic cements, which do not generate any exothermicity during setting. The exothermic reactions during the setting of phosphate cements can cause tissue damage during the administration of injectable compositions and hence a solution to the problem is sought via microwave processing. This solution through microwave exposure is based on a phenomenon that microwave irradiation can remove all water molecules from the alkaline earth phosphate cement paste to temporarily stop the setting reaction while preserving the active precursor phase in the formulation. The setting reaction can be initiated a second time by adding aqueous medium, but without any exothermicity. Second, a special emphasis is placed on using this technique to synthesize magnesium phosphate cements for orthopedic applications with their enhanced mechanical properties and possible uses as drug and protein delivery vehicles. The as-synthesized cements were evaluated for the occurrences of exothermic reactions, setting times, presence of Mg-phosphate phases, compressive strength levels, microstructural features before and after soaking in (simulated body fluid) SBF, and in vitro cytocompatibility responses. The major results show that exposure to microwaves solves the exothermicity problem, while simultaneously improving the mechanical performance of hardened cements and reducing the setting times. As expected, the cements are also found to be cytocompatible. Finally, it is observed that this process can be applied to calcium phosphate cements system (CPCs) as well. Based on the results, this microwave exposure provides a novel technique for the processing of injectable phosphate bone cement compositions. - Highlights: • A microwave assisted system for bone cement manufacturing • A solution to exothermicity problem of acid–base reaction based bone cement

  11. Cemented total hip arthroplasty with Boneloc bone cement.

    Science.gov (United States)

    Markel, D C; Hoard, D B; Porretta, C A

    2001-01-01

    Boneloc cement (WK-345, Biomet Inc, Warsaw, Ind) attempted to improve cement characteristics by reducing exotherm during polymerization, lowering residual monomer and solubility, raising molecular weight, and lowering airborne monomer and aromatic amines. To study the efficacy of this cement, a selected group of 20 patients were prospectively enrolled and followed up after hip arthroplasty. All components were cemented. During the enrollment period, approximately 70 other hip arthroplasties were performed. Clinical evaluation was based on the Harris hip score. Radiographic evaluation was based on assessment of position of the components, subsidence, and/or presence of radiolucencies. Patients had follow-up for an average of 42 months (11 to 58 months); 1 was lost to follow-up. Of these, 7 (35%) had failure at last follow-up. Despite its initial promise, Boneloc cement had an unacceptably high failure rate over a relatively short follow-up period and is not recommended for use. Despite the longevity and odor toxicity problems with conventional bone cement, new cement technologies must be approached with caution.

  12. Dust-off

    OpenAIRE

    Maycroft, Neil; Cheang, Shu Lea

    2015-01-01

    The fan of a motherboard switches on and off intermittently. It blows household dust, removed from the inside of a computer carcass, into the air. The dust then settles onto the motherboard, to be blown off again. This continual movement of dust is contained in the piece. However, it should remind us that the ceaseless creation and motion of unconfined dust accompanies all stages of the e-waste journey.

  13. Physics of interstellar dust

    CERN Document Server

    Krugel, Endrik

    2002-01-01

    The dielectric permeability; How to evaluate grain cross sections; Very small and very big particles; Case studies of Mie calculus; Particle statistics; The radiative transition probability; Structure and composition of dust; Dust radiation; Dust and its environment; Polarization; Grain alignment; PAHs and spectral features of dust; Radiative transport; Diffuse matter in the Milky Way; Stars and their formation; Emission from young stars. Appendices Mathematical formulae; List of symbols.

  14. Interactions between chloride and cement-paste materials.

    Science.gov (United States)

    Barberon, Fabien; Baroghel-Bouny, Véronique; Zanni, Hélène; Bresson, Bruno; d'Espinose de la Caillerie, Jean-Baptiste; Malosse, Lucie; Gan, Zehong

    2005-02-01

    The durability of cement-based materials with respect to exterior aggressions is one of the current priorities in civil engineering. Depending on their use, the cement-based materials can be exposed to different types of aggressive environments. For instance, damages to concrete structures in contact with a saline environment (sea water on bridges, deicing salts on roads, etc.) are of utmost importance. Upon exposure to saline water, Cl- ions penetrate into the structures and subsequently lead to reinforcement corrosion. Chloride attack is often combined with other aggressive influences such as temperature (e.g., freezing) or the ingress of other ions (e.g., sulfates in sea water). We therefore aim to explore the effect of sodium chloride (NaCl) on the structural chemistry of cement paste. Existing studies about reinforcement corrosion by chloride have focused on the penetration of Cl- ions and the comparison between "free" ions (water-soluble ions) and bound ones. However, little is known about the fixation mechanisms, the localization of Cl in the cement matrix and the structural interaction between Cl and the silicate and aluminate hydrate phases present in cement paste. We present here results of a multinuclear nuclear magnetic resonance study on the fixation of chloride in the hydration products and the characterization of new phases potentially appearing due to chloride ingress.

  15. Grout cement. ; Grout cement to fill ground/grout cement to fill cracks. Chunyuyo cement. ; Jiban chunyuyo cement /hibiware chunyuyo cement

    Energy Technology Data Exchange (ETDEWEB)

    Okaue, H. (Nittetsu Cement Co. Ltd., Hokkaido (Japan))

    1991-09-01

    Ground grout cement is grouted into the ground under high pressure in high water ratio (100 to 1000%) in the form of milk differing from concrete in terms of the water-cement ratio. The grouted milk is governed by characteristics of the cement the milk itself possesses, resulting in variable grouting modes, which are divided in fracture grouting, permeation grouting and boundary grouting. Their applications include cutting off of water in dams, ground reinforcement, prevention of water gushing in tunnel excavation, natural ground reinforcement, improvement of sandy soil and prevention of its collapse, and stabilization of ground for urban civil engineering works such as subway, water supply and sewerage constructions. Grout cement to fill cracks in concrete structures is so grouted into cracks that the slurry fills up contiguous cracks to a certain level and goes upward while pushing out air or water existing in the cracks. The slurry filled into the cracks solidifies and hardens while being absorbed into the concrete, and finally integrates with the concrete. The grout cement is used to rework such concrete structures as dams, tunnels, and bridge bases. 6 figs., 4 tabs.

  16. Dust in the Universe

    Science.gov (United States)

    Hemenway, Mary Kay; Armosky, Brad J.

    2004-01-01

    Space is seeming less and less like empty space as new discoveries and reexaminations fill in the gaps. And, ingenuity and technology, like the Spitzer Space Telescope, is allowing examination of the far reaches of the Milky Way and beyond. Even dust is getting its due, but not the dust everyone is familiar with. People seldom consider the dust in…

  17. 21 CFR 888.4200 - Cement dispenser.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cement dispenser. 888.4200 Section 888.4200 Food... DEVICES ORTHOPEDIC DEVICES Surgical Devices § 888.4200 Cement dispenser. (a) Identification. A cement dispenser is a nonpowered syringe-like device intended for use in placing bone cement (§ 888.3027)...

  18. Cements containing by-product gypsum

    Energy Technology Data Exchange (ETDEWEB)

    Bensted, J. [University of Greenwich, London (United Kingdom). School of Biological and Chemical Sciences

    1995-12-31

    Chemical by-product gypsum can readily replace natural gypsum in Portland cements and in blended cements like Portland pfa cement and Portland blast furnace cement without technical detriment in many instances. Indeed, sometimes the technical performance of the cement can be enhanced. The hydration chemistry is often changed, in that where there is at least some retardation of setting, more AFT phase (ettringite) is formed during early hydration at the expense of calcium silicate hydrates. By-product gypsum can also replace natural gypsum in speciality products like calcium aluminate cement-Portland cement mixes for producing quick setting cements and in calcium sulphoaluminate-type expansive cements. However, by-products gypsum have proved to be less successful for utilization in API Classes of oilwell cements, because of the greater difficulty in obtaining batch-to-batch consistency in properties like thickening time and slurry rheology. 11 refs., 3 figs., 5 tabs.

  19. 29 CFR 1910.1043 - Cotton dust.

    Science.gov (United States)

    2010-07-01

    ... exposure to cotton dust; (E) A copy of this standard and its appendices, except that the employer may keep... displacement of at least 2 liters and should be accurate to within ±30 milliliters. ii. technique for... testing that the same position be used and, if possible, the same spirometer. Particular attention...

  20. Toxicity of lunar dust

    CERN Document Server

    Linnarsson, Dag; Fubini, Bice; Gerde, Per; Karlsson, Lars L; Loftus, David J; Prisk, G Kim; Staufer, Urs; Tranfield, Erin M; van Westrenen, Wim

    2012-01-01

    The formation, composition and physical properties of lunar dust are incompletely characterised with regard to human health. While the physical and chemical determinants of dust toxicity for materials such as asbestos, quartz, volcanic ashes and urban particulate matter have been the focus of substantial research efforts, lunar dust properties, and therefore lunar dust toxicity may differ substantially. In this contribution, past and ongoing work on dust toxicity is reviewed, and major knowledge gaps that prevent an accurate assessment of lunar dust toxicity are identified. Finally, a range of studies using ground-based, low-gravity, and in situ measurements is recommended to address the identified knowledge gaps. Because none of the curated lunar samples exist in a pristine state that preserves the surface reactive chemical aspects thought to be present on the lunar surface, studies using this material carry with them considerable uncertainty in terms of fidelity. As a consequence, in situ data on lunar dust...

  1. Acute effect of glucan-spiked office dust on nasal and pulmonary inflammation in guinea pigs

    DEFF Research Database (Denmark)

    Straszek, Sune; Adamcakova-Dodd, Andrea; Nervana, Metwali

    2007-01-01

     office dust and glucan on nasal and pulmonary inflammation. This is relevant for humans with occupational exposure in waste handling and farming and buildings with mold problems.  Office dust collected from Danish offices was spiked with 1% (1-3)-β-glucan (curdlan). Guinea pig nasal cavity volume was measured...... office dust exposures produced a delayed nasal sub-acute congestion in guinea pigs compared to office dust alone but extrapolated to nasal congestion in humans, paralleling the nasal congestion seen in human volunteers exposed to the same dust, it may not have clinical importance....

  2. House dust mite control measures for asthma: systematic review

    DEFF Research Database (Denmark)

    Gøtzsche, Peter C.; Johansen, Helle Krogh

    2008-01-01

    The major allergen in house dust comes from mites. We performed a systematic review of the randomized trials that had assessed the effects of reducing exposure to house dust mite antigens in the homes of people with mite-sensitive asthma, and had compared active interventions with placebo...... improved (relative risk 1.01, 95% CI 0.80-1.27), asthma symptom scores (standardized mean difference -0.04, 95% CI -0.15 to 0.07) or in medication usage (standardized mean difference -0.06, 95% CI -0.18 to 0.07). Chemical and physical methods aimed at reducing exposure to house dust mite allergens cannot...

  3. Alternative Fuels in Cement Production

    DEFF Research Database (Denmark)

    Larsen, Morten Boberg

    for the most significant alternative fuel energy contributors in the German cement industry. Solid alternative fuels are typically high in volatile content and they may differ significantly in physical and chemical properties compared to traditional solid fossil fuels. From the process point of view......The substitution of alternative for fossil fuels in cement production has increased significantly in the last decade. Of these new alternative fuels, solid state fuels presently account for the largest part, and in particular, meat and bone meal, plastics and tyre derived fuels (TDF) accounted......, considering a modern kiln system for cement production, the use of alternative fuels mainly influences 1) kiln process stability (may accelerate build up of blockages preventing gas and/or solids flow), 2) cement clinker quality, 3) emissions, and 4) decreased production capacity. Kiln process stability...

  4. Magnesium substitution in brushite cements.

    Science.gov (United States)

    Alkhraisat, Mohammad Hamdan; Cabrejos-Azama, Jatsue; Rodríguez, Carmen Rueda; Jerez, Luis Blanco; Cabarcos, Enrique López

    2013-01-01

    The use of magnesium-doped ceramics has been described to modify brushite cements and improve their biological behavior. However, few studies have analyzed the efficiency of this approach to induce magnesium substitution in brushite crystals. Mg-doped ceramics composed of Mg-substituted β-TCP, stanfieldite and/or farringtonite were reacted with primary monocalcium phosphate (MCP) in the presence of water. The cement setting reaction has resulted in the formation of brushite and newberyite within the cement matrix. Interestingly, the combination of SAED and EDX analyses of single crystal has indicated the occurrence of magnesium substitution within brushite crystals. Moreover, the effect of magnesium ions on the structure, and mechanical and setting properties of the new cements was characterized as well as the release of Ca(2+) and Mg(2+) ions. Further research would enhance the efficiency of the system to incorporate larger amounts of magnesium ions within brushite crystals.

  5. Formation, release and control of dioxins in cement kilns.

    Science.gov (United States)

    Karstensen, Kåre Helge

    2008-01-01

    /precalciner kilns generally seems to have lower emissions than older wet-process cement kilns. It seems that the main factors stimulating formation of PCDD/PCDFs is the availability of organics in the raw material and the temperature of the air pollution control device. Feeding of materials containing elevated concentrations of organics as part of raw-material-mix should therefore be avoided and the exhaust gases should be cooled down quickly in long wet and long dry cement kilns without preheating. PCDD/PCDFs could be detected in all types of solid samples analysed: raw meal, pellets and slurry; alternative raw materials as sand, chalk and different ashes; cement kiln dust, clinker and cement. The concentrations are however generally low, similar to soil and sediment.

  6. Exposure to organic dust and respiratory disorders.

    NARCIS (Netherlands)

    Smid, T.

    1993-01-01

    Chapter 1 summarises the background of the study. Nonmalignant respiratory disorders account for a significant part of sick leave diagnoses (19%), disability pension (3.4%) and mortality (7%). The rate of chronic obstructive pulmonary diseases has risen substantially during the last 10 to 20 years.

  7. Portland cement-blast furnace slag blends in oilwell cementing applications

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, D.T.; DiLullo, G.; Hibbeler, J. [and others

    1995-12-31

    Recent investigations of blast furnace slag cementing technologies. have been expanded to include Portland cement/blast furnace slag blends. Mixtures of Portland cement and blast furnace slag, while having a long history of use in the construction industry, have not been used extensively in oilwell cementing applications. Test results indicate that blending blast furnace slag with Portland cement produces a high quality well cementing material. Presented are the design guidelines and laboratory test data relative to mixtures of blast furnace slag and Portland cements. Case histories delineating the use of blast furnace slag - Portland cement blends infield applications are also included.

  8. Calcium Orthophosphate Cements and Concretes

    Directory of Open Access Journals (Sweden)

    Sergey V. Dorozhkin

    2009-03-01

    Full Text Available In early 1980s, researchers discovered self-setting calcium orthophosphate cements, which are a bioactive and biodegradable grafting material in the form of a powder and a liquid. Both phases form after mixing a viscous paste that after being implanted, sets and hardens within the body as either a non-stoichiometric calcium deficient hydroxyapatite (CDHA or brushite, sometimes blended with unreacted particles and other phases. As both CDHA and brushite are remarkably biocompartible and bioresorbable (therefore, in vivo they can be replaced with newly forming bone, calcium orthophosphate cements represent a good correction technique for non-weight-bearing bone fractures or defects and appear to be very promising materials for bone grafting applications. Besides, these cements possess an excellent osteoconductivity, molding capabilities and easy manipulation. Furthermore, reinforced cement formulations are available, which in a certain sense might be described as calcium orthophosphate concretes. The concepts established by calcium orthophosphate cement pioneers in the early 1980s were used as a platform to initiate a new generation of bone substitute materials for commercialization. Since then, advances have been made in the composition, performance and manufacturing; several beneficial formulations have already been introduced as a result. Many other compositions are in experimental stages. In this review, an insight into calcium orthophosphate cements and concretes, as excellent biomaterials suitable for both dental and bone grafting application, has been provided.

  9. Continuous respirable mine dust monitor development

    Energy Technology Data Exchange (ETDEWEB)

    Cantrell, B.K.; Williams, K.L.; Stein, S.W. [and others

    1996-12-31

    In June 1992, the Mine Safety and Health Administration (MSHA) published the Report of the Coal Mine Respirable Dust Task Group, Review of the Program to Control Respirable Coal Mine Dust in the United States. As one of its recommendations, the report called for the accelerated development of two mine dust monitors: (1) a fixed-site monitor capable of providing continuous information on dust levels to the miner, mine operator, and to MSHA, if necessary, and (2) a personal sampling device capable of providing both a short-term personal exposure measurement as well as a full-shift measurement. In response to this recommendation, the U.S. Bureau of Mines initiated the development of a fixed-site machine-mounted continuous respirable dust monitor. The technology chosen for monitor development is the Rupprecht and Patashnick Co., Inc. tapered element oscillating microbalance. Laboratory and in-mine tests have indicated that, with modification, this sensor can meet the humidity and vibration requirements for underground coal mine use. The U.S. Department of Energy Pittsburgh Research Center (DOE-PRC) is continuing that effort by developing prototypes of a continuous dust monitor based on this technology. These prototypes are being evaluated in underground coal mines as they become available. This effort, conducted as a joint venture with MSHA, is nearing completion with every promise of success.

  10. Deposition of inhaled wood dust in the nasal cavity.

    Science.gov (United States)

    Tian, Z F; Inthavong, K; Tu, J Y

    2007-11-01

    Detailed deposition patterns of inhaled wood dust in an anatomically accurate nasal cavity were investigated using computational fluid dynamics (CFD) techniques. Three wood dusts, pine dust, heavy oak dust, and light oak dust, with a particle size distribution generated by machining (Chung et al., 2000), were simulated at an inhalation flow rate of 10 L/min. It was found that the major particle deposition sites were the nasal valve region and anterior section of the middle turbinate. Wood dust depositing in these regions is physiologically removed much more slowly than in other regions. This leads to the surrounding layer of soft tissues being damaged by the deposited particles during continuous exposure to wood dust. Additionally, it was found that pine dust had a higher deposition efficiency in the nasal cavity than the two oak dusts, due to the fact that it comprises a higher proportion of larger sized particles. Therefore, this indicates that dusts with a large amount of fine particles, such as those generated by sanding, may penetrate the nasal cavity and travel further into the lung.

  11. Low pH Cements

    Energy Technology Data Exchange (ETDEWEB)

    Savage, David; Benbow, Steven [Quintessa Ltd., Henley-on-Thames (United Kingdom)

    2007-05-15

    The development of low-pH cements for use in geological repositories for radioactive waste stems from concerns over the potential for deleterious effects upon the host rock and other EBS materials (notably bentonite) under the hyperalkaline conditions (pH > 12) of cement pore fluids. Low pH cement (also known as low heat cement) was developed by the cement industry for use where large masses of cement (e.g. dams) could cause problems regarding heat generated during curing. In low pH cements, the amount of cement is reduced by substitution of materials such as fly ash, blast furnace slag, silica fume, and/or non-pozzolanic silica flour. SKB and Posiva have ruled out the use of blast furnace slag and fly-ash and are focusing on silica fume as a blending agent. Currently, no preferred composition has been identified by these agencies. SKB and Posiva have defined a pH limit {<=} 11 for cement grout leachates. To attain this pH, blending agents must comprise at least 50 wt % of dry materials. Because low pH cement has little, or no free portlandite, the cement consists predominantly of calcium silicate hydrate (CSH) gel with a Ca/Si ratio {<=} 0.8. Although there are potential implications for the performance of the spent fuel and cladding due to the presence of hyperalkaline fluids from cement, the principal focus for safety assessment lies with the behaviour of bentonite. There are a number of potential constraints on the interaction of hyperalkaline cement pore fluids with bentonite, including mass balance, thermodynamic issues, mass transport, and kinetics, but none of these is likely to be limiting if conventional OPC cements are employed in repository construction. Nevertheless: Low-pH cements may supply approximately 50 % less hydroxyl ions than conventional OPC for a given volume of cement, but mass balance constraints are complicated by the uncertainty concerning the type of secondary minerals produced during cement-bentonite interaction. The change of aqueous

  12. Low pH Cements

    Energy Technology Data Exchange (ETDEWEB)

    Savage, David; Benbow, Steven [Quintessa Ltd., Henley-on-Thames (United Kingdom)

    2007-05-15

    The development of low-pH cements for use in geological repositories for radioactive waste stems from concerns over the potential for deleterious effects upon the host rock and other EBS materials (notably bentonite) under the hyperalkaline conditions (pH > 12) of cement pore fluids. Low pH cement (also known as low heat cement) was developed by the cement industry for use where large masses of cement (e.g. dams) could cause problems regarding heat generated during curing. In low pH cements, the amount of cement is reduced by substitution of materials such as fly ash, blast furnace slag, silica fume, and/or non-pozzolanic silica flour. SKB and Posiva have ruled out the use of blast furnace slag and fly-ash and are focusing on silica fume as a blending agent. Currently, no preferred composition has been identified by these agencies. SKB and Posiva have defined a pH limit {<=} 11 for cement grout leachates. To attain this pH, blending agents must comprise at least 50 wt % of dry materials. Because low pH cement has little, or no free portlandite, the cement consists predominantly of calcium silicate hydrate (CSH) gel with a Ca/Si ratio {<=} 0.8. Although there are potential implications for the performance of the spent fuel and cladding due to the presence of hyperalkaline fluids from cement, the principal focus for safety assessment lies with the behaviour of bentonite. There are a number of potential constraints on the interaction of hyperalkaline cement pore fluids with bentonite, including mass balance, thermodynamic issues, mass transport, and kinetics, but none of these is likely to be limiting if conventional OPC cements are employed in repository construction. Nevertheless: Low-pH cements may supply approximately 50 % less hydroxyl ions than conventional OPC for a given volume of cement, but mass balance constraints are complicated by the uncertainty concerning the type of secondary minerals produced during cement-bentonite interaction. The change of aqueous

  13. A review of binders used in cemented paste tailings for underground and surface disposal practices.

    Science.gov (United States)

    Tariq, Amjad; Yanful, Ernest K

    2013-12-15

    Increased public awareness of environmental issues coupled with increasingly stringent environmental regulations pertaining to the disposal of sulphidic mine waste necessitates the mining industry to adopt more competent and efficient approaches to manage acid rock drainage. Cemented paste tailings (CPT) is an innovative form of amalgamated material currently available to the mining industry in developed countries. It is made usually from mill tailings mingled with a small amount of binder (customarily Portland cement) and water. The high cost associated with production and haulage of ordinary Portland cement and its alleged average performance as a sole binder in the long term (due to vulnerability to internal sulphate attack) have prompted users to appraise less expensive and technically efficient substitutes for mine tailings paste formulations. Generally, these binders include but are not limited to sulphate resistant cements, and/or as a partial replacement for Portland cement by artificial pozzolans, natural pozzolans, calcium sulphate substances and sodium silicates. The approach to designing environmentally efficient CPT is to ensure long-term stability and effective control over environmental contaminants through the use of composite binder systems with enhanced engineering properties to cater for inherit deficiencies in the individual constituents. The alkaline pore solution created by high free calcium rich cement kiln dust (CKD) (byproduct of cement manufacturing) is capable of disintegrating the solid glassy network of artificial pozzolans to produce reactive silicate and aluminate species when attacked by (OH(-)) ions. The augmented pozzolanic reactivity of CKD-slag and CKD-fly ash systems may produce resilient CPT. Since cemented paste comprising mine tailings and binders is a relatively new technology, a review of the binding materials used in such formulations and their performance evaluation in mechanical fill behaviour was considered pertinent in

  14. Study the air pollution due to Dorud Cement Plant (in Iran

    Directory of Open Access Journals (Sweden)

    Vahid Mokhtari

    2016-09-01

    Full Text Available Cement industry is one of the most important industries in the country. Dorud Cement Plant is one of the largest and oldest Iran's cement factories, which is working in the center of the city of Dorud. In this study, aimed to investigate air pollution resulting from Dorud cement plant, the parameters of CO, CO2, O2, NO, NO2, NOx, SO2, dry dust particles, particles weight and environmental particulates of PM10 and PM2.5 were measured with conventional methods of measuring emissions from industrial chimneys and by using automatic measuring equipment, and the rates of emissions from the chimneys of the plant were calculated during a working year. These measurements were made over three months, from February 20, 2015 to May 21, 2015, at 3 stations of Link1-k1, Link2-k1 and Link3-k1, which are the chimneys of the three-lines of the plant. It was found in this study that the chimney No. 3 enters the maximum contaminant into the environment. The results also showed that based on the standards defined for the cement industry, Dorud cement plant meets the relative optimal conditions in terms of comparing performance with the standards, and the emissions from the factory are less than the enacted standards for this industry. Also, the preventive measures and equipment for reducing emissions established in this industrial unit have a relative utility. In this study, the factors including type of raw materials used, old production lines and old factory equipment, type of producing cement and proximity to the city were determined as main reasons for the emissions produced by this industry. Also, some management solutions such as the use of environment designing inside the manufacturing process of the plant and outside the plant, using flame-reducing, construction of a new phase and relocating the plant were suggested to reduce emissions from Dorud cement plants.

  15. 21 CFR 888.3027 - Polymethylmethacrylate (PMMA) bone cement.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Polymethylmethacrylate (PMMA) bone cement. 888... Polymethylmethacrylate (PMMA) bone cement. (a) Identification. Polymethylmethacrylate (PMMA) bone cement is a device...: Polymethylmethacrylate (PMMA) Bone Cement.”...

  16. Research of fluidized bed cement clinker sintering system by pilot plant; Ryudosho cement shosei gijutsu no kaihatsu. 7

    Energy Technology Data Exchange (ETDEWEB)

    Sugiyama, T. [Center for Coal Utilization, Japan, Tokyo (Japan); Sato, N.; Hashimoto, I.; Nakatsuka, M. [The Cement Association of Japan, Tokyo (Japan)

    1996-09-01

    While a cement manufacturing process generally performs sintering by using a rotary kiln, a development work has been carried out as a subsidy operation of the Agency of Natural Resources and Energy on a cement sintering technology using a fluidized bed consisted of two furnaces: a jet flow bed granulating furnace and a fluidized bed sintering furnace. This paper reports the results of tests and researches performed during fiscal 1995. A plant with a scale of 20 ton-a-day production started in 1993 after having gone through bench scale tests. The year 1995 conducted by August its performance evaluation, review of the operation method and the safety criteria, and generalization of the tests. A multi-stage cyclone system has been employed in the preheating equipment for cement material powder. A number of improvements have been realized in the aspects of construction and operation, such as stabilization of dust collecting efficiency by employing a high-efficiency type cyclone, and operation with reduced pressure variation. Based on these results, a construction had been progressed in parallel on a new plant upscaled to 200 ton-a-day production. The new plant was completed in December, 1995. 9 figs., 8 tabs.

  17. Effect of mattress and pillow encasings on children with asthma and house dust mite allergy

    DEFF Research Database (Denmark)

    Halken, Susanne; Høst, Arne; Niklassen, Ulla

    2003-01-01

    House dust mite (HDM) allergy is a frequent cause of allergic asthma in children. Reduction of exposure seems to be the most logical way to treat these patients.......House dust mite (HDM) allergy is a frequent cause of allergic asthma in children. Reduction of exposure seems to be the most logical way to treat these patients....

  18. House dust mite control measures for asthma

    DEFF Research Database (Denmark)

    Gøtzsche, Peter C.; Johansen, Helle Krogh

    2008-01-01

    antigens in the homes of people with mite-sensitive asthma. SEARCH STRATEGY: PubMed and The Cochrane Library (last searches Nov 2007), reference lists. SELECTION CRITERIA: Randomised trials of mite control measures vs placebo or no treatment in people with asthma known to be sensitive to house dust mites.......07), or in medication usage (standardised mean difference -0.06, 95% CI -0.18 to 0.07). AUTHORS' CONCLUSIONS: Chemical and physical methods aimed at reducing exposure to house dust mite allergens cannot be recommended. It is doubtful whether further studies, similar to the ones in our review, are worthwhile. If other...

  19. Association between PM10 concentrations and school absences in proximity of a cement plant in northern Italy.

    Science.gov (United States)

    Marcon, Alessandro; Pesce, Giancarlo; Girardi, Paolo; Marchetti, Pierpaolo; Blengio, Gianstefano; de Zolt Sappadina, Simona; Falcone, Salvatore; Frapporti, Guglielmo; Predicatori, Francesca; de Marco, Roberto

    2014-03-01

    Dusts are one of the main air pollutants emitted during cement manufacturing. A substantial part of these are breathable particles that are less than 10 μm in diameter (PM10), which represent a potential threat for the health of the exposed population. This study aimed at evaluating the short-term effects of PM10 concentrations on the health of children, aged 6-14 years, who attended the schools in Fumane (Italy), in proximity (1.2 km) to a large cement plant. School absenteeism was used as a proxy indicator of child morbidity. Time series of daily school absences and PM10 concentrations were collected for 3 school-years from 2007 to 2010 (541 school-days, 462 children on average). The associations between PM10 concentrations and school absence rates in the same day (lag0) and in the following 4 days (lag1 to lag4) were evaluated using generalised additive models, smoothed for medium/long term trends and adjusted for day of the week, influenza outbreaks, daily temperature and rain precipitations. The average concentration of PM10 in the period was 34 (range: 4-183) μg/m(3). An average 10 μg/m(3) increase of PM10 concentration in the previous days (lag0-4) was associated with a statistically significant 2.5% (95%CI: 1.1-4.0%) increase in the rate of school absences. The highest increase in the absence rates (2.4%; 95%CI: 1.2-3.5%) was found 2 days after exposure (lag2). These findings provide epidemiological evidence of the acute health effects of PM10 in areas with annual concentrations that are lower than the legal European Union limit of 40 μg/m(3), and support the need to establish more restrictive legislative standards.

  20. Intraoperative monitoring for safety of total hip arthroplasty using third-generation cementing technique

    Institute of Scientific and Technical Information of China (English)

    LI Zi-jian; ZHANG Ke; YANG Hong; LIU Yan; L(U) Jing-qiao

    2009-01-01

    Background Controversies on the safety of the cement application between cemented and uncemented total hip arthroplasty (THA) have been existing for decades. The purpose of this study was to observe the changes in mean arterial pressure (MAP), heart rate (HR) and oxygen pressure (PaO2) during cemented THA, and to evaluate the intraoperative safety of using the third-generation cementing technique and investigate whether the intraoperative risk is higher in acute femoral neck fracture patients than non-traumatic patients. Methods Forty-two patients who underwent cemented THA between November 2005 and September 2007 were prospectively included in this study. The third-generation cementing technique as vacuum mixing and pulsatile lavage was used strictly. The MAP and HR were monitored and documented during each operation. Blood gas analysis was performed at exposure, cup implantation, stem implantation and wound closure. MAP, HR and PaO2 were compared between pre- and post-cement application. Comparisons of MAP, HR and PaO2 between patients with acute femoral neck fracture and non-traumatic patiens were performed as well. Results No intraoperative cardiopulmonary complication occurred in these cases. No obvious changes were observed in MAP, HR and PaO2 after cement application. There was no significant difference in MAP, HR and PaO2 between acute femoral fracture patients (18 patients) and non-traumatic patients (24 patients).Conclusions The results of this study suggested that the invasive blood pressure monitoring and blood gas analysis are essential for patients undergoing cemented THA, especially for patients with femoral neck fracture. The third-generation cementing technique is safe to use in THA.

  1. Properties and Acceleration Mechanism of Cement Mortar Added with Low Alkaline Liquid State Setting Accelerator

    Institute of Scientific and Technical Information of China (English)

    PAN Zhihua; WANG Xuebing; LIU Weiqing

    2014-01-01

    Low alkaline liquid state setting accelerator(LSA) for Portland cement was prepared in laboratory from aqueous solution of several inorganic sulfate salts and some organic chemical substances. Properties of cement with addition of LSA relating to its setting time and strength development as well as its resistance to sulfate attack for short and long term exposure were experimentally examined. The experimental results showed that 5%-7%addition of LSA significantly accelerated the initial and final setting of Portland cement in the presence or absence of the blending of mineral admixtures, the initial and final setting time being less than 3 min and 6 min respectively. Meanwhile, the early 1 day curing age compressive strength increased remarkably by 20%, while the late 28th day curing age compressive strength remained almost unchanged as compared with that of the reference accelerator free cement mortar specimen. Furthermore, mortar specimens of cement added with LSA and exposed to 5%Na2SO4 solution showed their excellent resistance to sulfate attack, with their short and long term curing age resistance coefficient to sulfate attack being around 1.04 to 1.17, all larger than 1.0. XRD analysis on hardened cement paste specimens at very early curing ages of several minutes disclosed the existence of more ettringite in specimens added with LSA than that of the reference specimens, meanwhile SEM observation also revealed the existence of well crystallized ettringite at very early hydration stage, suggesting that the accelerated setting of Portland cement can be attributed to the early and rapid formation of ettringite over the whole cement paste matrix due to the introduction of LSA. MIP measurement revealed that hardened cement paste specimens with the addition of LSA presented less medium diameter pores, more proportion of small pores and less proportion of large capillary pores, which is in a very good coincidence with the improvement of strength development of

  2. Cementation of Loose Sand Particles based on Bio-cement

    Institute of Scientific and Technical Information of China (English)

    RONG Hui; QIAN Chunxiang

    2014-01-01

    Loose sand particles could be cemented to sandstone by bio-cement (microbial induced magnesium carbonate). The bio-sandstone was firstly prepared, and then the compressive strength and the porosity of the sandstone cemented by microbial induced magnesium carbonate were tested to characterize the cementation effectiveness. In addition, the formed mineral composition and the microstructure of bio-sandstone were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The experimental results show that the feasibility of binding loose sand particles using microbial induced magnesium carbonate precipitation is available and the acquired compressive strength of bio-sandstone can be excellent at certain ages. Moreover, the compressive strength and the porosity could be improved with the increase of microbial induced magnesium carbonate content. XRD results indicate that the morphology of magnesium carbonate induced by microbe appears as needles and SEM results show that the cementation of loose sand particles to sandstone mainly relies on the microbial induced formation of magnesium carbonate precipitation around individual particles and at particle-particle contacts.

  3. Operational Dust Prediction

    Science.gov (United States)

    Benedetti, Angela; Baldasano, Jose M.; Basart, Sara; Benincasa, Francesco; Boucher, Olivier; Brooks, Malcolm E.; Chen, Jen-Ping; Colarco, Peter R.; Gong, Sunlin; Huneeus, Nicolas; Jones, Luke; Lu, Sarah; Menut, Laurent; Morcrette, Jean-Jacques; Mulcahy, Jane; Nickovic, Slobodan; Garcia-Pando, Carlos P.; Reid, Jeffrey S.; Sekiyama, Thomas T.; Tanaka, Taichu Y.; Terradellas, Enric; Westphal, Douglas L.; Zhang, Xiao-Ye; Zhou, Chun-Hong

    2014-01-01

    Over the last few years, numerical prediction of dust aerosol concentration has become prominent at several research and operational weather centres due to growing interest from diverse stakeholders, such as solar energy plant managers, health professionals, aviation and military authorities and policymakers. Dust prediction in numerical weather prediction-type models faces a number of challenges owing to the complexity of the system. At the centre of the problem is the vast range of scales required to fully account for all of the physical processes related to dust. Another limiting factor is the paucity of suitable dust observations available for model, evaluation and assimilation. This chapter discusses in detail numerical prediction of dust with examples from systems that are currently providing dust forecasts in near real-time or are part of international efforts to establish daily provision of dust forecasts based on multi-model ensembles. The various models are introduced and described along with an overview on the importance of dust prediction activities and a historical perspective. Assimilation and evaluation aspects in dust prediction are also discussed.

  4. Marine durability of 15 year old concrete specimens made with ordinary portland, slag, and fly ash cements

    Energy Technology Data Exchange (ETDEWEB)

    Mohammed, T.U.; Yamaji, T.; Hamada, H. [Port and Harbor Research Inst., Ministry of Land, Infrastructure and Transport (Japan); Aoyama, T. [PS Corp. (Japan)

    2001-07-01

    A study was conducted in which the marine durability of ordinary portland cement, slag and fly ash cement was examined using 15 year old plain and reinforced concrete cylindrical specimens. In addition, the performance of these cements was also examined in another study for pre-cracked reinforced concrete prism samples. The process of manufacturing cement emits huge amounts of carbon dioxide into the global atmosphere. Replacing a portion of the cement with by-products from the steel industry and thermal power plants (which are both huge emitters of carbon dioxide) can lower carbon dioxide emissions and also solve the disposal issue of slag and fly ash while increasing the long-term durability of concrete structures. In this study, concrete cylindrical specimens were made of ordinary portland cement, slag and fly ash cements. Water-to-cement ratios were 0.45 and 0.55 and the compressive strength of the concrete, corrosion of the steel bars, and chloride-ion concentrations in the concrete were evaluated. It was shown that, with the exception of fly ash cements, the compressive strength of most cements increased after 15 years of exposure compared to its 28 day strength. Type C slag cement demonstrated the best performance against chloride-ion at the surface of concrete made with slag and fly ash. Voids in the steel-concrete interface make it possible for corrosion pits to develop. The use of seawater as mixing water results in earlier strength development at 28 days and does not cause to the strength of the concrete to regress after 15-years of exposure, but it causes more corrosion of steel bars at a lower cover depth. Corrosion of steel bars is not an issue at deeper cover depths. 15 refs., 18 tabs., 8 figs.

  5. Influence of Blended Cements with Calcareous Fly Ash on Chloride Ion Migration and Carbonation Resistance of Concrete for Durable Structures

    Directory of Open Access Journals (Sweden)

    Michał A. Glinicki

    2016-01-01

    Full Text Available The objective of this paper is to examine the possible use of new blended cements containing calcareous fly ash in structural concrete, potentially adequate for structural elements of nuclear power plants. The investigation included five new cements made with different contents of non-clinker constituents: calcareous fly ash, siliceous fly ash, ground granulated blastfurnace slag, and a reference cement—ordinary Portland cement. The influence of innovative cements on the resistance of concrete to chloride and carbonation exposure was studied. Additionally, an evaluation of the microstructure was performed using optical microscopy on concrete thin sections. Test results revealed a substantial improvement of the resistance to chloride ion penetration into concrete containing blended cements. The resistance was higher for increased clinker replacement levels and increased with curing time. However, concrete made with blended cements exhibited higher depth of carbonation than the Portland cement concrete, except the Portland-fly ash cement with 14.3% of calcareous fly ash. The thin sections analysis confirmed the values of the carbonation depth obtained from the phenolphthalein test. Test results indicate the possible range of application for new cements containing calcareous fly ash.

  6. Polychlorinated biphenyls in settled dust from informal electronic waste recycling workshops and nearby highways in urban centers and suburban industrial roadsides of Chennai city, India: Levels, congener profiles and exposure assessment.

    Science.gov (United States)

    Chakraborty, Paromita; Prithiviraj, Balasubramanian; Selvaraj, Sakthivel; Kumar, Bhupander

    2016-12-15

    Polychlorinated biphenyls (PCBs) were quantified in settled dust collected from informal electronic waste (e-waste) recycling workshops and nearby highways in the urban centers and roadside dust from the suburban industrial belt of Chennai city in India. Further dust samples were subjected to a high resolution field emission scanning electron microscope equipped with an energy dispersive X-ray spectrometer (FESEM/EDX) to characterize the shape, size and elemental composition of the dust particles. Geomean of total PCB concentration followed the following order: informal e-waste metal recovery workshops (53ngg(-1))>e-waste dismantling sites (3.6ngg(-1))>nearby highways (1.7ngg(-1))>suburban industrial roadsides (1.6ngg(-1)). In e-waste workshops, tetra, penta and hexa-PCB homologs contributed two third of Σ26PCB concentration. Informal e-waste recycling workshops contributed more than 80% concentration of all the PCB congeners loaded in the first principal component. Predominance of dioxin like PCBs, PCB-l14, -118 and -126 in the e-waste metal recovery sites were presumably due to combustion and pyrolytic processes performed during recycling of electrical components. According to the morphology and elemental composition, settled dust from e-waste workshops were irregular particles heavily embedded with toxic metals and industrial roadside dust were distinct angular particles. FESEM revealed that average particle size (in Ferret diameter) increased in the following order: e-waste recycling workshops (0.5μm)

  7. Stone dusting process advance

    Energy Technology Data Exchange (ETDEWEB)

    Matt Ryan; David Humphreys [Mining Attachments (Qld.) Pty Ltd. (Australia)

    2009-01-15

    The coal mining industry has, for many years, used dry stone dust or calcium carbonate (CaCO{sub 3}) in the prevention of the propagation of coal dust explosions throughout their underground mines in Australia. In the last decade wet stone dusting has been introduced. This is where stone dust and water are mixed together to form a paste like slurry. This mixture is pumped and sprayed on to the underground roadway surfaces. This method solved the contamination of the intake airways but brought with it a new problem known as 'caking'. Caking is the hardened layer that is formed as the stone dust slurry dries. It was proven that this hardened layer compromises the dispersal characteristics of the stone dust and therefore its ability to suppress a coal dust explosion. This project set out to prove a specially formulated, non toxic slurry additive and process that could overcome the caking effect. The slurry additive process combines dry stone dust with water to form a slurry. The slurry is then treated with the additive and compressed air to create a highly vesicular foam like stone dusted surface. The initial testing on a range of additives and the effectiveness in minimising the caking effect of wet dusting were performed at Applied Chemical's research laboratory in Melbourne, Victoria and independently tested at the SGS laboratory in Paget, Queensland. The results from these tests provided the platform to conduct full scale spraying trials at the Queensland Mines Rescue Station and Caledon Coal's Cook Colliery, Blackwater. The project moved into the final stage of completion with the collection of data. The intent was to compare the slurry additive process to dry stone dusting in full-scale methane explosions at the CSIR Kloppersbos explosion facility in Kloppersbos, South Africa.

  8. Seating load parameters impact on dental ceramic reinforcement conferred by cementation with resin-cements.

    LENUS (Irish Health Repository)

    Addison, Owen

    2010-09-01

    Cementation of all-ceramic restorations with resin-cements has been demonstrated to reduce the incidence of fracture in service. The aim was to investigate the influence of loading force and loading duration applied during cementation on the reinforcement conferred by a resin-cement on a leucite reinforced glass-ceramic.

  9. 76 FR 76760 - Gray Portland Cement and Cement Clinker From Japan

    Science.gov (United States)

    2011-12-08

    ... Portland Cement and Cement Clinker From Japan Determination On the basis of the record \\1\\ developed in the... antidumping duty order on gray Portland cement and cement clinker from Japan would be likely to lead to... the Commission are contained in USITC Publication 4281 (December 2011), entitled Gray Portland...

  10. Polycyclic aromatic hydrocarbons in household dust near diesel transport routes.

    Science.gov (United States)

    Kuo, Chung-Yih; Chen, Heng-Chun; Cheng, Fang-Ching; Huang, Li-Ru; Chien, Po-Shan; Wang, Jing-Ya

    2012-02-01

    A river-dredging project has been undertaken in Nantou, Taiwan. A large number of diesel vehicles carrying gravel and sand shuttle back and forth on the main roads. Ten stations along major thoroughfares were selected as the exposure sites for testing, while a small village located about 9 km from a main traffic route was selected as the control site. Levels of household dust loading at the exposure sites (60.3 mg/m(2)) were significantly higher than those at the control site (38.2 mg/m(2)). The loading (μg/m(2)) of t-PAHs (total polycyclic aromatic hydrocarbons) in the household dust at the exposure sites was significantly higher (P < 0.05) than was the case at the control site. The diagnostic ratios of PAHs showed that diesel emissions were the dominant source of PAHs at the exposure sites. The lack of a significant correlation between the concentrations of Fe and t-PAHs suggested that the t-PAHs in household dust might come from diverse sources. However, a significant correlation (P = 0.003) between the concentrations of Mo and t-PAHs implied that the most of the t-PAHs in the household dust might have resulted from diesel emissions. The lifetime cancer risks of BaP(eq) from household dust exposure were markedly higher than those resulting from inhalation exposure.

  11. Antibacterial potential of contemporary dental luting cements.

    Science.gov (United States)

    Daugela, Povilas; Oziunas, Rimantas; Zekonis, Gediminas

    2008-01-01

    The aims of this investigation were to evaluate the antibacterial activities of different types of dental luting cements and to compare antibacterial action during and after setting. Agar diffusion testing was used to evaluate the antibacterial properties of seven types of dental luting cements (glass ionomer cements (GICs), resin modified GICs, resin composite, zinc oxide eugenol, zinc oxide non-eugenol, zinc phosphate, zinc polycarboxylate cements) on Streptococcus mutans bacteria. Instantly mixed zinc phosphate cements showed the strongest antibacterial activity in contrast to the non-eugenol, eugenol and resin cements that did not show any antibacterial effects. Non-hardened glass ionomer, resin modified and zinc polycarboxylate cements exhibited moderate antibacterial action. Hardened cements showed weaker antibacterial activities, than those ones applied right after mixing.

  12. Freezing resistance of high iron phoasphoaluminate cement

    Science.gov (United States)

    Zhang, S. X.; Lu, L. C.; Wang, S. D.; Zhao, P. Q.; Gong, C. C.

    2017-03-01

    The influence of freeze-thaw cycle on the mechanical properties of high iron phoasphoaluminate cement was investigated in the present study. The visual examination was conducted to evaluate the surface damage. The deterioration considering the weight loss, modulus loss of relative dynamic elastic and strength loss of mortar were also investigated. The morphology of hydration products were analysed by SEM. Compared with ordinary Portland cement and sulphoaluminate cement, the frost resistance of high iron phosphoraluminate cement is better. Hydration products of high iron phoasphoaluminate cement contain sheet crystals, and a lot of gel form a dense three-dimensional network structure, which results in a lower porosity. Different from ordinary Portland cement, the hydration product of high iron phoasphoaluminate cement does not contain Ca(OH)2, and low alkalinity reduces its osmotic pressure. The lower porosity and osmotic pressure are the two main reasons which causes in the higher frost resistance of high iron phoasphoaluminate cement.

  13. Application of ESP for gas cleaning in cement industry--with reference to India.

    Science.gov (United States)

    Bapat, J D

    2001-02-16

    Electrostatic precipitators (ESP) are used for gas cleaning in almost every section of cement manufacture. Application of ESP is studied, keeping in view Indian conditions. The characterisation of dust emissions has been done for different units, such as rotary kiln and raw mill, alkali by-pass, clinker cooler, cement and coal mill, in terms of exit gas quantity, temperature, dew point, dust content and particle size. It is seen that all these characteristics have a wide range of variance. The ESP system must effectively deal with these variations. The fundamental analytical expression governing the performance of ESP, i.e. the Deutsch equation, and that for particle migration velocity, were analysed to predict the effect of major operating parameters, namely particle size, temperature and applied voltage. Whereas the migration velocity (and the efficiency) varies directly with the particle size, it is proportional to the square and square root of applied voltage and absolute temperature of the gas, respectively. The increase in efficiency due to temperature is not seen in dc based ESP, perhaps due to more pronounced negative effect on the applied voltage due to the increase in dust resistivity at higher temperatures. The effect of gas and dust characteristics on the collection efficiency of ESP, as seen in the industrial practice, is summarised. Some main process and design improvements effectively dealing with the problem of gas and dust characteristics have been discussed. These are gas conditioning, pulse energization, ESP-fabric filter (FF) combination, improved horizontal flow as well as open top ESP.Generally, gas conditioning entails higher operating and maintenance costs. Pulse energization allows the use of hot gas, besides reducing the dust emission and power consumption. The improved horizontal flow ESP has been successfully used in coal dust cleaning. The open top or vertical flow ESP has a limitation on collection efficiency as it provides for only

  14. Hyperstrength Cement Testing.

    Science.gov (United States)

    1986-03-01

    18 E. SPECIMEN BLANKS ............................................... 22 III ENVIRONMENTAL HISTORY EFFECTS ON FLEXURAL...Moisture Exposure ............. 28 7 Thermal Environmental History Effects on Flexural Properties ......... 32 8 Flexural Vibration Damping and Modulus...All tests were performed at room temperature. Section III is concerned with environmental history effects. The flexur- al properties were used to judge

  15. Porosity and Permeability Evolution in Cemented Rock Cores under Reactive Flowing Conditions: Comparative Analysis between Limestone and Sandstone Host Rocks

    Science.gov (United States)

    Cao, P.; Karpyn, Z.; Li, L.

    2013-12-01

    CO2-brine has the potential to alter wellbore cement in depleted oil and gas reservoirs under geological CO2 sequestration conditions. A better understanding of CO2-brine-cement-rock interaction is needed to evaluate the seal integrity of candidate sequestration formation in the long run. This work investigates possible alteration of wellbore cement when bonded by different host formation rock upon exposure to CO2-saturated brine. Composite cement-sandstone and cement-limestone core samples were created to perform reactive coreflood experiments. After an eight-day dynamic flow-through period, both cores had a similar extent of porosity increase, while the cement-limestone core experienced a ten-fold higher increase in permeability. With the aid of X-ray Micro-CT imaging and Scanning Electron Microscopy, it is observed that cement underwent greater degradation at the cement-sandstone interface. Degradation of cement-limestone core mainly took place on the host rock matrix. Worm holes were developed and a solution channel was formed in the limestone, creating a dominant flow path that altered both flow and reaction behavior. Limestone buffered the injected acidic brine preventing further deterioration of cement near the core outlet. Changes in fluid chemistry of limestone and sandstone coreflood effluents are compared. Results from this work are aimed at assisting the development and validation of robust reactive transport models through direct measurement of cemented rock core porosity and permeability evolution as well as the effluent aqueous chemistry change. This will subsequently improve predictive capabilities of reactive transport models associated with CO2 sequestration in geologic environments. Permeability Evolution of Cement-Rock Core Sample during Dynamic Flow of CO2-Brine

  16. 76 FR 24519 - Gray Portland Cement and Cement Clinker From Japan; Institution of a Five-Year Review Concerning...

    Science.gov (United States)

    2011-05-02

    ... COMMISSION Gray Portland Cement and Cement Clinker From Japan; Institution of a Five-Year Review Concerning the Antidumping Duty Order on Gray Portland Cement and Cement Clinker From Japan AGENCY: United States... determine whether revocation of the antidumping duty order on gray portland cement and cement clinker...

  17. 76 FR 50252 - Gray Portland Cement and Cement Clinker From Japan; Scheduling of an Expedited Five-Year Review...

    Science.gov (United States)

    2011-08-12

    ... COMMISSION Gray Portland Cement and Cement Clinker From Japan; Scheduling of an Expedited Five-Year Review Concerning the Antidumping Duty Order on Gray Portland Cement and Cement Clinker From Japan AGENCY: United... cement and cement clinker from Japan would be likely to lead to continuation or recurrence of...

  18. Galactic dust properties

    Science.gov (United States)

    Paradis, D.

    2011-12-01

    Recent studies have shown evidence for variations in the dust emissivity law with temperature and wavelength. A recent dust emission model, called TLS model (for two-level systems), based on the description of the disordered internal structure of the amorphous dust grains has been developped to interpret observations in the far-infrared/submillimeter (FIR/submm) domain. A recent work focusing on the comparison between data of the diffuse interstellar medium seen by FIRAS-WMAP, as well as Archeops compact sources, with the TLS model allowed us to constrain the model parameters characterizing the general Galactic dust properties. Using the newly available Herschel/Hi-GAL data of the inner Galactic plane, we report a 500 μm emissivity excess in the peripheral parts of the Galactic plane, that can reach up to 20% of the emissivity. Results of the TLS modeling indicate significant changes in the dust properties from the central to peripheral parts of the Galactic plane.

  19. Effective dust control systems on concrete dowel drilling machinery.

    Science.gov (United States)

    Echt, Alan S; Sanderson, Wayne T; Mead, Kenneth R; Feng, H Amy; Farwick, Daniel R; Farwick, Dawn Ramsey

    2016-09-01

    Rotary-type percussion dowel drilling machines, which drill horizontal holes in concrete pavement, have been documented to produce respirable crystalline silica concentrations above recommended exposure criteria. This places operators at potential risk for developing health effects from exposure. United States manufacturers of these machines offer optional dust control systems. The effectiveness of the dust control systems to reduce respirable dust concentrations on two types of drilling machines was evaluated under controlled conditions with the machines operating inside large tent structures in an effort to eliminate secondary exposure sources not related to the dowel-drilling operation. Area air samples were collected at breathing zone height at three locations around each machine. Through equal numbers of sampling rounds with the control systems randomly selected to be on or off, the control systems were found to significantly reduce respirable dust concentrations from a geometric mean of 54 mg per cubic meter to 3.0 mg per cubic meter on one machine and 57 mg per cubic meter to 5.3 mg per cubic meter on the other machine. This research shows that the dust control systems can dramatically reduce respirable dust concentrations by over 90% under controlled conditions. However, these systems need to be evaluated under actual work conditions to determine their effectiveness in reducing worker exposures to crystalline silica below hazardous levels.

  20. PERFORMANCE OF PULVERIZED SLAG-SUBSTITUTED CEMENT

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The Portland cement is equivalently substituted by slag micropowders with various specific areas. The workability,activity and acid-corrosion resistance of the slag-substituted cements are investigated,the activation of gypsum is discussed,also the porosity and pore distribution of mortars of the slag micropowders cement are determined by mercury intrusion porosimetry.

  1. 21 CFR 872.3275 - Dental cement.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Dental cement. 872.3275 Section 872.3275 Food and... DENTAL DEVICES Prosthetic Devices § 872.3275 Dental cement. (a) Zinc oxide-eugenol—(1) Identification... filling or as a base cement to affix a temporary tooth filling, to affix dental devices such as crowns...

  2. Cementation in adhesive dentistry: the weakest link

    NARCIS (Netherlands)

    Jongsma, L.A.

    2012-01-01

    Het succesvol bevestigen van tandrestauraties is een belangrijke en veeleisende procedure. Met behulp van cement wordt het restauratiemateriaal aan de tandstructuur verbonden. Op die manier worden twee hechtvlakken gecreëerd: het raakvlak tussen tand en cement, en het raakvlak tussen cement en resta

  3. Performance of Periwinkle Shell Ash Blended Cement Concrete Exposed to Magnesium Sulphate

    Directory of Open Access Journals (Sweden)

    Umoh A.A.

    2013-01-01

    Full Text Available The study examined the compressive strength of periwinkle shell ash (PSA blended cement concrete in magnesium sulphate medium. Specimens were prepared from designed characteristics strength of 25 MPa. The cement replacement with PSA ranged between 0 and 40% by volume. A total of 180 cube specimens were cast and cured in water. At 28 days curing, 45 specimens each were transferred into magnesium sulphate of 1%, 3%, and 5% solution, while others were continuously cured in water and tested at 62, 92, and 152 days. The results revealed a higher loss in compressive strength with the control mix, and that it increases with increased in MgSO4 concentration and exposure period, whereas, the attack on the PSA blended cement concrete was less and the least value recorded by 10% PSA content. Therefore, the study concluded that the optimum percentage replacement of cement with 10% PSA could mitigate magnesium sulphate attack.

  4. ADVANCED CEMENTS FOR GEOTHERMAL WELLS

    Energy Technology Data Exchange (ETDEWEB)

    SUGAMA,T.

    2007-01-01

    Using the conventional well cements consisting of the calcium silicate hydrates (CaO-SiO{sub 2}-H{sub 2}O system) and calcium aluminum silicate hydrates (CaO-Al{sub 2}O{sub 3}-SiO{sub 2}-H{sub 2}O system) for the integrity of geothermal wells, the serious concern confronting the cementing industries was their poor performance in mechanically supporting the metallic well casing pipes and in mitigating the pipe's corrosion in very harsh geothermal reservoirs. These difficulties are particularly acute in two geological regions: One is the deep hot downhole area ({approx} 1700 m depth at temperatures of {approx} 320 C) that contains hyper saline water with high concentrations of CO{sub 2} (> 40,000 ppm) in conjunction with {approx} 100 ppm H{sub 2}S at a mild acid of pH {approx} 5.0; the other is the upper well region between the well's surface and {approx} 1000 m depth at temperatures up to 200 C. The specific environment of the latter region is characterized by highly concentrated H{sub 2}SO{sub 4} (pH < 1.5) brine containing at least 5000 ppm CO{sub 2}. When these conventional cements are emplaced in these harsh environments, their major shortcoming is their susceptibility to reactions with hot CO{sub 2} and H{sub 2}SO4, thereby causing their deterioration brought about by CO{sub 2}-catalyzed carbonation and acid-initiated erosion. Such degradation not only reduced rapidly the strength of cements, lowering the mechanical support of casing pipes, but also increased the extent of permeability of the brine through the cement layer, promoting the rate of the pipe's corrosion. Severely carbonated and acid eroded cements often impaired the integrity of a well in less than one year; in the worst cases, casings have collapsed within three months, leading to the need for costly and time-consuming repairs or redrilling operations. These were the reasons why the geothermal well drilling and cementing industries were concerned about using conventional well

  5. Asian dust storm particles induce a broad toxicological transcriptional program in human epidermal keratinocytes.

    Science.gov (United States)

    Choi, Hyun; Shin, Dong Wook; Kim, Wonnyon; Doh, Seong-Jae; Lee, Soo Hwan; Noh, Minsoo

    2011-01-15

    Exposure to airborne dust particles originated from seasonal Asian dust storms in Chinese and Mongolian deserts results in increased incidence of a range of diseases including asthma, contact dermatitis and conjunctivitis. The areas affected by Asian dust particles extend from East China to the west coast of North America. In order to study toxicological mechanisms in human skin, we evaluated the effects of dust particles collected during Asian dust storms (Asian dust particles) on gene expression in human epidermal keratinocytes (HEK). In HEK, exposure to Asian dust particles significantly increased gene expressions of cytochrome P450 1A1 (CYP1A1), CYP1A2, and CYP1B1, which is an indication of aryl hydrocarbon receptor (AHR) activation. In addition, Asian dust particles increased gene transcription of the cytokines IL-6, IL-8, and GM-CSF, which have broad pro-inflammatory and immunomodulatory properties. Asian dust particles significantly up-regulated expression of caspase 14 in HEK, suggesting that Asian dust particles directly affect keratinocyte differentiation. We also demonstrated that protein extract of pollen, a material frequently adsorbed onto Asian dust particles, potentially contributes to the increased transcription of IL-6, CYP1A1, CYP1A2, and CYP1B1. Taken together, these studies suggest that Asian dust particles can exert toxicological effects on human skin through the activation of the cellular detoxification system, the production of pro-inflammatory and immunomodulatory cytokines, and changes in the expression of proteins essential in normal epidermal differentiation.

  6. Strength development in concrete with wood ash blended cement and use of soft computing models to predict strength parameters

    Directory of Open Access Journals (Sweden)

    S. Chowdhury

    2015-11-01

    Full Text Available In this study, Wood Ash (WA prepared from the uncontrolled burning of the saw dust is evaluated for its suitability as partial cement replacement in conventional concrete. The saw dust has been acquired from a wood polishing unit. The physical, chemical and mineralogical characteristics of WA is presented and analyzed. The strength parameters (compressive strength, split tensile strength and flexural strength of concrete with blended WA cement are evaluated and studied. Two different water-to-binder ratio (0.4 and 0.45 and five different replacement percentages of WA (5%, 10%, 15%, 18% and 20% including control specimens for both water-to-cement ratio is considered. Results of compressive strength, split tensile strength and flexural strength showed that the strength properties of concrete mixture decreased marginally with increase in wood ash contents, but strength increased with later age. The XRD test results and chemical analysis of WA showed that it contains amorphous silica and thus can be used as cement replacing material. Through the analysis of results obtained in this study, it was concluded that WA could be blended with cement without adversely affecting the strength properties of concrete. Also using a new statistical theory of the Support Vector Machine (SVM, strength parameters were predicted by developing a suitable model and as a result, the application of soft computing in structural engineering has been successfully presented in this research paper.

  7. Strength development in concrete with wood ash blended cement and use of soft computing models to predict strength parameters.

    Science.gov (United States)

    Chowdhury, S; Maniar, A; Suganya, O M

    2015-11-01

    In this study, Wood Ash (WA) prepared from the uncontrolled burning of the saw dust is evaluated for its suitability as partial cement replacement in conventional concrete. The saw dust has been acquired from a wood polishing unit. The physical, chemical and mineralogical characteristics of WA is presented and analyzed. The strength parameters (compressive strength, split tensile strength and flexural strength) of concrete with blended WA cement are evaluated and studied. Two different water-to-binder ratio (0.4 and 0.45) and five different replacement percentages of WA (5%, 10%, 15%, 18% and 20%) including control specimens for both water-to-cement ratio is considered. Results of compressive strength, split tensile strength and flexural strength showed that the strength properties of concrete mixture decreased marginally with increase in wood ash contents, but strength increased with later age. The XRD test results and chemical analysis of WA showed that it contains amorphous silica and thus can be used as cement replacing material. Through the analysis of results obtained in this study, it was concluded that WA could be blended with cement without adversely affecting the strength properties of concrete. Also using a new statistical theory of the Support Vector Machine (SVM), strength parameters were predicted by developing a suitable model and as a result, the application of soft computing in structural engineering has been successfully presented in this research paper.

  8. Biomonitoring with epiphytic lichens as a complementary method for the study of mercury contamination near a cement plant.

    Science.gov (United States)

    Ljubič Mlakar, Tanja; Horvat, Milena; Kotnik, Jože; Jeran, Zvonka; Vuk, Tomaž; Mrak, Tanja; Fajon, Vesna

    2011-10-01

    The study was focused on understanding the mercury contamination caused by a cement plant. Active and passive biomonitoring with epiphytic lichens was combined with other instrumental measurements of mercury emissions, mercury concentrations in raw materials, elemental mercury concentrations in air, quantities of dust deposits, temperatures, precipitation and other measurements from the cement plant's regular monitoring programme. Active biomonitoring with transplanted lichens Pseudevernia furfuracea (L.) Zopf was performed at seven of the most representative sites around the cement plant and one distant reference site for periods of 3, 6 and 12 months. In situ lichens of different species were collected at the beginning of the monitoring period at the same sites. Mercury speciation of the plant exhaust gas showed that the main form of emitted mercury is reactive gaseous mercury Hg²⁺, which is specific for cement plants. Elemental mercury in air was measured in different meteorological conditions using a portable mercury detector. Concentrations in air were relatively low (on average below 10 ng m⁻³). In situ lichens showed Hg concentrations comparable to lichens taken from the background area for transplantation, indicating that the local pollution is not severe. Transplanted lichens showed an increase of mercury, especially at one site near the cement plant. A correlation between precipitation and Hg uptake was not found probably due to a rather uniform rainfall in individual periods. Dust deposits did not influence Hg uptake significantly. Lichens vitality was affected over longer biomonitoring periods, probably due to some elements in dust particles, their alkalinity and the influence of other emissions. Mercury uptake measured in vital transplanted lichens was in a good correlation with the working hours (i.e. emitted Hg quantity) of the kiln. The study showed that selected lichens could be used to detect low to moderate Hg emissions from a cement plant

  9. Evaluation of cement production using a pressurized fluidized-bed combustor

    Energy Technology Data Exchange (ETDEWEB)

    DeLallo, M.; Eshbach, R.

    1994-01-01

    There are several primary conclusions which can be reached and used to define research required in establishing the feasibility of using PFBC-derived materials as cement feedstock. 1. With appropriate blending almost any material containing the required cement-making materials can be utilized to manufacture cement. However, extensive blending with multiple materials or the use of ash in relatively small quantities would compromise the worth of this concept. 2. The composition of a potential feedstock must be considered not only with respect to the presence of required materials, but just as significantly, with respect to the presence and concentration of known deleterious materials. 3. The processing costs for rendering the feedstock into an acceptable composition and the energy costs associated with both processing and burning must be considered. It should be noted that the cost of energy to produce cement, expressed as a percentage of the price of the product is higher than for any other major industrial product. Energy consumption is, therefore, a major issue. 4. The need for conformance to environmental regulations has a profound effect on the cement industry since waste materials can neither be discharged to the atmosphere or be shipped to a landfill. 5. Fifth, the need for achieving uniformity in the composition of the cement is critical to controlling its quality. Unfortunately, certain materials in very small concentrations have the capability to affect the rate and extent to which the cementitious compound in portland cement are able to form. Particularly critical are variations in the ash, the sulfur content of the coal or the amount and composition of the stack dust returned to the kiln.

  10. 'Nuisance Dust' - a Case for Recalibration?

    Science.gov (United States)

    Datson, Hugh; Marker, Brian

    2013-04-01

    This paper considers the case for a review and recalibration of limit values and acceptability criteria for 'nuisance dust', a widely encountered but poorly defined and regulated aspect of particulate matter pollution. Specific dust fractions such as PM10 and asbestiforms are well characterised and have limit values enshrined in legislation. National, and international, limit values for acceptable concentrations of PM10 and other fractions of particulate matter have been defined and agreed. In the United Kingdom (UK), these apply to both public and workplace exposures. By contrast, there is no standard definition or universal criteria against which acceptable levels for 'nuisance dust' can be assessed. This has implications for land-use planning and resource utilisation. Without meaningful limit values, inappropriate development might take place too near to residential dwellings or land containing economically important mineral resources may be effectively sterilised. Furthermore, the expression 'nuisance dust' is unhelpful in that 'nuisance' has a specific meaning in environmental law whilst 'nuisance dust' is often taken to mean 'generally visible particulate matter'. As such, it is associated with the social and broader environmental impacts of particulate matter. PM10 concentrations are usually expressed as a mass concentration over time. These can be determined using a range of techniques. While results from different instruments are generally comparable, data obtained from alternative methods for measuring 'nuisance dust' are rarely interchangeable. In the UK, many of the methods typically used are derived from approaches developed under the HMIP (Her Majesty's Inspectorate of Pollution) regime in the 1960s onwards. Typical methods for 'nuisance dust' sampling focus on measurement of dust mass (from the weight of dust collected in an open container over time) or dust soiling (from loss of reflectance and or obscuration of a surface discoloured by dust over

  11. Lunar Airborne Dust Toxicity Hazard Assessments (Invited)

    Science.gov (United States)

    Cooper, B. L.; McKay, D. S.; Taylor, L. A.; Wallace, W. T.; James, J.; Riofrio, L.; Gonzalez, C. P.

    2009-12-01

    The Lunar Airborne Dust Toxicity Assessment Group (LADTAG) is developing data to set the permissible limits for human exposure to lunar dust. This standard will guide the design of airlocks and ports for EVA, as well as the requirements for filtering and monitoring the atmosphere in habitable vehicles, rovers and other modules. LADTAG’s recommendation for permissible exposure limits will be delivered to the Constellation Program in late 2010. The current worst-case exposure limit of 0.05 mg/m3, estimated by LADTAG in 2006, reflects the concern that lunar dust may be as toxic as quartz dust. Freshly-ground quartz is known to be more toxic than un-ground quartz dust. Our research has shown that the surfaces of lunar soil grains can be more readily activated by grinding than quartz. Activation was measured by the amount of free radicals generated—activated simulants generate Reactive Oxygen Species (ROS) i.e., production of hydroxyl free radicals. Of the various influences in the lunar environment, micrometeorite bombardment probably creates the most long-lasting reactivity on the surfaces of grains, although solar wind impingement and short-wavelength UV radiation also contribute. The comminution process creates fractured surfaces with unsatisfied bonds. When these grains are inhaled and carried into the lungs, they will react with lung surfactant and cells, potentially causing tissue damage and disease. Tests on lunar simulants have shown that dissolution and leaching of metals can occur when the grains are exposed to water—the primary component of lung fluid. However, simulants may behave differently than actual lunar soils. Rodent toxicity testing will be done using the respirable fraction of actual lunar soils (particles with physical size of less than 2.5 micrometers). We are currently separating the fine material from the coarser material that comprises >95% of the mass of each soil sample. Dry sieving is not practical in this size range, so a new system

  12. Thoughts on the Current Cement Industry Development

    Institute of Scientific and Technical Information of China (English)

    Gan Zhihe

    2003-01-01

    According to the analysis of cement capacity andits relations with macro economy running index, the mainreasons for the present rapid development of cement capacityare the rapid development of economy and the shot up ofwhole society fixed asset investment. According to the presentspeed of economy development, cement still enjoys a po-tential increase, So here has not been an overall excessivepopularity of cement industry. The best way to prevent lowlevel repeated construction is to promote the development ofnew dry- process cement as well as try to get rid of blindness.

  13. Variability of exposure and estimation of cumulative exposure in a manually operated coal mine

    Energy Technology Data Exchange (ETDEWEB)

    Mamuya, S.H.D.; Bratveit, M.; Mwaiselage, J.; Moen, B.E. [University of Bergen, Bergen (Norway). Center for International Health

    2006-10-15

    This study aims at estimating variability in exposure to respirable dust and assessing whether the a priori grouping by job team is appropriate for an exposure-response study on respiratory effects among workers in a manually operated coal mine in Tanzania. Furthermore, estimated exposure levels were used to calculate cumulative exposure. Full-shift personal respirable dust samples (n = 204) were collected from 141 randomly chosen workers at underground and surface work sites. The geometric mean exposure for respirable dust varied from 0.07 mg m{sup -3} for office workers to 1.96 mg m{sup -3} for the development team. The analogous range of respirable quartz exposure was 0.006-0.073 mg m{sup -3}. Variance components were estimated using random effect models. For most job teams the within-worker variance component was considerably higher than the between-worker variance component. For respirable dust the estimated attenuation of the linear exposure-response relationship was low (5.9%) when grouping by job team. Grouping by job team was considered appropriate for studying the association between current dust exposure and respiratory effects. Based on the estimated worker-specific mean exposure in the job teams, the arithmetic mean cumulative exposure for the 299 workers who participated in the epidemiological part of the study was 38.1 mg. yr m{sup -3} for respirable dust and 2.0 mg. yr m{sup -3} for quartz.

  14. Wood dust: an occupational hazard which increases the risk of respiratory disease.

    Science.gov (United States)

    Baran, S; Teul, I

    2007-11-01

    The main source of emission of harmful dust in the work place comes from technological processes. European legislation aims to minimize the health risks from dangerous substances in the workplace. European Directives are transferred into national legislation. Such matters as risk assessment, technical measures, and exposure limits are regulated by the law. In Poland, manufacturing processes in which hardwood dust is discharged, are considered as carcinogenic. Numerous studies have shown that occupational exposure to wood dust is strongly associated with the development of cancer of the nasal cavity and paranasal sinuses (NSC), but data regarding the development of lung cancer are conflicting and inconclusive. In the study, the exposure to inhalable wood dust was assessed among wood-workers in mid-west Poland. The assessment of occupational exposure was made on the basis of measurements of the concentration of dust in the work place. This was defined by exposure rates to dust in reference to daily work time and by comparing that to the maximum acceptable concentration values of dust defined by the regulation by the Minister of Work and Social Policy. The health assessment of workers was made on the basis of periodical medical check-ups, whose range and frequency is defined by the regulation of the Minister of Health and Social Security. The study did not show effects of wood dust exposure on the of lung cancer.

  15. CO2 Capture by Cement Raw Meal

    DEFF Research Database (Denmark)

    Pathi, Sharat Kumar; Lin, Weigang; Illerup, Jytte Boll

    2013-01-01

    The cement industry is one of the major sources of CO2 emissions and is likely to contribute to further increases in the near future. The carbonate looping process has the potential to capture CO2 emissions from the cement industry, in which raw meal for cement production could be used...... as the sorbent. Cyclic experiments were carried out in a TGA apparatus using industrial cement raw meal and synthetic raw meal as sorbents, with limestone as the reference. The results show that the CO2 capture capacities of the cement raw meal and the synthetic raw meal are comparable to those of pure limestone...... that raw meal could be used as a sorbent for the easy integration of the carbonate looping process into the cement pyro process for reducing CO2 emissions from the cement production process....

  16. Understanding cement mechanical behavior in SAGD wells

    Energy Technology Data Exchange (ETDEWEB)

    Xie, J.; Zahacy, T. A. [C-FER Technologies (Canada)

    2011-07-01

    In the heavy oil industry, the steam assisted gravity drainage process is often used to enhance oil recovery but it can cause cracks in the cement sheath. These cracks are the result of high steam temperatures and thermal expansion. In order to mitigate this risk, improved well designs are required. The aim of this paper is to present the mechanical behavior of the cement sheath during the heating phase. An analysis of the impact of design and operating parameters was conducted through thermal hydraulic and thermal mechanical analyses to assess cement integrity. These analyses were then performed on an example of an SAGD project in the southern part of the Athabasca oilsands region to assess the performance of the cement sheath. Results showed that potential damage to the cement can be reduced by slow heating and a lower Young's modulus cement blend. This paper makes recommendations for optimizing cement design in thermal recovery wells.

  17. Microwave assisted preparation of magnesium phosphate cement (MPC) for orthopedic applications: a novel solution to the exothermicity problem.

    Science.gov (United States)

    Zhou, Huan; Agarwal, Anand K; Goel, Vijay K; Bhaduri, Sarit B

    2013-10-01

    There are two interesting features of this paper. First, we report herein a novel microwave assisted technique to prepare phosphate based orthopedic cements, which do not generate any exothermicity during setting. The exothermic reactions during the setting of phosphate cements can cause tissue damage during the administration of injectable compositions and hence a solution to the problem is sought via microwave processing. This solution through microwave exposure is based on a phenomenon that microwave irradiation can remove all water molecules from the alkaline earth phosphate cement paste to temporarily stop the setting reaction while preserving the active precursor phase in the formulation. The setting reaction can be initiated a second time by adding aqueous medium, but without any exothermicity. Second, a special emphasis is placed on using this technique to synthesize magnesium phosphate cements for orthopedic applications with their enhanced mechanical properties and possible uses as drug and protein delivery vehicles. The as-synthesized cements were evaluated for the occurrences of exothermic reactions, setting times, presence of Mg-phosphate phases, compressive strength levels, microstructural features before and after soaking in (simulated body fluid) SBF, and in vitro cytocompatibility responses. The major results show that exposure to microwaves solves the exothermicity problem, while simultaneously improving the mechanical performance of hardened cements and reducing the setting times. As expected, the cements are also found to be cytocompatible. Finally, it is observed that this process can be applied to calcium phosphate cements system (CPCs) as well. Based on the results, this microwave exposure provides a novel technique for the processing of injectable phosphate bone cement compositions.

  18. The role of glass composition in the behaviour of glass acetic acid and glass lactic acid cements.

    Science.gov (United States)

    Shahid, Saroash; Billington, R W; Pearson, G J

    2008-02-01

    Cements have recently been described, made from glass ionomer glass reacted with acetic and lactic acid instead of polymeric carboxylic acid. From their behaviour a theory relating to a possible secondary setting mechanism of glass ionomer has been adduced. However, only one glass (G338) was used throughout. In this study a much simpler glass ionomer glass (MP4) was compared with G338. This produced very different results. With acetic acid G338 formed cement which became resistant to water over a period of hours, as previously reported, MP4 formed cement which was never stable to water. With lactic acid G338 behaved similarly to G338 with acetic acid, again as reported, but MP4 produced a cement which was completely resistant to water at early exposure and unusually became slightly less resistant if exposure was delayed for 6 h or more. These findings indicate that the theories relating to secondary setting in glass ionomer maturation may need revision.

  19. Nano Dust Analyzer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a new highly sensitive inst