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Sample records for benzene exposure identified

  1. Diversity Outbred Mice Identify Population-Based Exposure Thresholds and Genetic Factors that Influence Benzene-Induced Genotoxicity

    Science.gov (United States)

    Gatti, Daniel M.; Morgan, Daniel L.; Kissling, Grace E.; Shockley, Keith R.; Knudsen, Gabriel A.; Shepard, Kim G.; Price, Herman C.; King, Deborah; Witt, Kristine L.; Pedersen, Lars C.; Munger, Steven C.; Svenson, Karen L.; Churchill, Gary A.

    2014-01-01

    Background Inhalation of benzene at levels below the current exposure limit values leads to hematotoxicity in occupationally exposed workers. Objective We sought to evaluate Diversity Outbred (DO) mice as a tool for exposure threshold assessment and to identify genetic factors that influence benzene-induced genotoxicity. Methods We exposed male DO mice to benzene (0, 1, 10, or 100 ppm; 75 mice/exposure group) via inhalation for 28 days (6 hr/day for 5 days/week). The study was repeated using two independent cohorts of 300 animals each. We measured micronuclei frequency in reticulocytes from peripheral blood and bone marrow and applied benchmark concentration modeling to estimate exposure thresholds. We genotyped the mice and performed linkage analysis. Results We observed a dose-dependent increase in benzene-induced chromosomal damage and estimated a benchmark concentration limit of 0.205 ppm benzene using DO mice. This estimate is an order of magnitude below the value estimated using B6C3F1 mice. We identified a locus on Chr 10 (31.87 Mb) that contained a pair of overexpressed sulfotransferases that were inversely correlated with genotoxicity. Conclusions The genetically diverse DO mice provided a reproducible response to benzene exposure. The DO mice display interindividual variation in toxicity response and, as such, may more accurately reflect the range of response that is observed in human populations. Studies using DO mice can localize genetic associations with high precision. The identification of sulfotransferases as candidate genes suggests that DO mice may provide additional insight into benzene-induced genotoxicity. Citation French JE, Gatti DM, Morgan DL, Kissling GE, Shockley KR, Knudsen GA, Shepard KG, Price HC, King D, Witt KL, Pedersen LC, Munger SC, Svenson KL, Churchill GA. 2015. Diversity Outbred mice identify population-based exposure thresholds and genetic factors that influence benzene-induced genotoxicity. Environ Health Perspect 123:237

  2. Changes in the peripheral blood transcriptome associated with occupational benzene exposure identified by cross-comparison on two microarray platforms

    Energy Technology Data Exchange (ETDEWEB)

    McHale, Cliona M.; Zhang, Luoping; Lan, Qing; Li, Guilan; Hubbard, Alan E.; Forrest, Matthew S.; Vermeulen, Roel; Chen, Jinsong; Shen, Min; Rappaport, Stephen M.; Yin, Songnian; Smith, Martyn T.; Rothman, Nathaniel

    2009-03-01

    Benzene is an established cause of leukemia and a possible cause of lymphoma in humans but the molecular pathways underlying this remain largely undetermined. This study sought to determine if the use of two different microarray platforms could identify robust global gene expression and pathway changes associated with occupational benzene exposure in the peripheral blood mononuclear cell (PBMC) gene expression of a population of shoe-factory workers with well-characterized occupational exposures to benzene. Microarray data was analyzed by a robust t-test using a Quantile Transformation (QT) approach. Differential expression of 2692 genes using the Affymetrix platform and 1828 genes using the Illumina platform was found. While the overall concordance in genes identified as significantly associated with benzene exposure between the two platforms was 26% (475 genes), the most significant genes identified by either array were more likely to be ranked as significant by the other platform (Illumina = 64%, Affymetrix = 58%). Expression ratios were similar among the concordant genes (mean difference in expression ratio = 0.04, standard deviation = 0.17). Four genes (CXCL16, ZNF331, JUN and PF4), which we previously identified by microarray and confirmed by real-time PCR, were identified by both platforms in the current study and were among the top 100 genes. Gene Ontology analysis showed over representation of genes involved in apoptosis among the concordant genes while Ingenuity{reg_sign} Pathway Analysis (IPA) identified pathways related to lipid metabolism. Using a two-platform approach allows for robust changes in the PBMC transcriptome of benzene-exposed individuals to be identified.

  3. Benzene exposures in urban areas

    International Nuclear Information System (INIS)

    Valerio, F.; Pala, M.; Cipolla, M.; Stella, A.

    2001-01-01

    Benzene exposures in urban areas were reviewed. Available data confirm that both in USA and Europe, benzene concentrations measured by fixed outdoor monitoring stations underestimate personal exposures of urban residents. Indoor sources, passive smoke and the high exposures during commuting time may explain this difference. Measures in European towns confirm that very frequently mean daily personal exposures to benzene exceed 10 μg/m 3 , current European air quality guideline for this carcinogenic compound [it

  4. Occupational exposure to benzene in South Korea.

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    Kang, Seong-Kyu; Lee, Mi-Young; Kim, Tae-Kyun; Lee, Jeong-Oh; Ahn, Yeon Soon

    2005-05-30

    Benzene has been used in various industries as glues or solvents in Korea. Since 1981, a preparation containing more than 1% benzene is not allowed to be manufactured, used or dealt with in the workplace, except in laboratories and in those situations benzene must be used in a completely sealed process as specified in Industrial Safety and Health Act (ISHA). Claims for compensation of hematopoietic diseases related to benzene have been rising even though the work environment has been improved. This study was conducted to assess the status of benzene exposure in different industries in Korea. We reviewed the claimed cases investigated by the Korea Occupational Safety and Health Agency (KOSHA) between 1992 and 2000. The Survey of National Work Environment Status in 1998 was analyzed to assume the number of workers and factories exposed to benzene. In 2000, six factories were investigated to evaluate benzene exposure. Personal air monitoring was performed in 61 workers and urine samples were collected from 57 workers to measure trans,trans-muconic acid (t,t-MA). Hematologic examination has performed. Thirty-four cases of hematopoietic diseases were investigated by KOSHA including eight cases of myelodysplastic syndrome and eight cases of acute myelocytic leukemia. Eight cases were accepted as related to benzene exposure. The number of workers possibly exposed to benzene can be estimated to be 196,182 workers from 6219 factories based on the database. The geometric mean of benzene in air was 0.094 (0.005-5.311) ppm. Seven samples were higher than 1 ppm but they did not go over the 10 ppm occupational exposure limit (OEL) value in Korea. The geometric mean of trans,trans-muconic acid in urine was 0.966 (0.24-2.74) mg/g creatinine. The benzene exposure level was low except in a factory where benzene was used to polymerize other chemicals. The ambient benzene from 0.1 to 1 ppm was significantly correlated with urine t,t-MA concentration (r=0.733, p<0.01). Hematologic

  5. Variability of benzene exposure among filling station attendants

    International Nuclear Information System (INIS)

    Carere, A.; Iacovella, N.; Turrio Baldassarri, L.; Fuselli, S.; Iavarone, I.; Lagorio, S.; Proietto, A.R.

    1996-12-01

    A monitoring survey of filling station attendants aimed at identifying sources of variability of exposure to benzene and other aromatics was carried out. Concurrent samples of the worker's breathing zone air, atmospheric air in the service station proximity, and gasoline were collected, along with information about daily workloads and other exposure-related factors. Benzene personal exposure was characterised by a small between-worker variability and a predominant within-worker variance component. Such elevated day-to-day variability yields to imprecise estimates of mean personal exposure. Almost 70% of the overall personal exposure variance was explained by a model including daily benzene from dispensed fuel, presence of a shelter over the refueling area, amount of fuel supplied to the station if a delivery occurred, and background atmospheric benzene concentration

  6. Urban benzene pollution and population exposure

    Energy Technology Data Exchange (ETDEWEB)

    Cocheo, V.; Sacco, P.; Boaretto, C. [Fondazione Salvatore, Maugeri-IRCCS, Padova (Italy); Saeger, E. de; Ballesta, P.P. [Joint Research Centre, Ispra (Italy); Skov, H. [National Environmental Research Institute, Frederiksborgvej (Denmark); Goelen, E. [Vlaamse Instelling voor Technologisch Onderzoek, Mol (Belgium); Gonzalez, N. [Institut National de l' environnement Industriel et des Risques, 60 - Verneuil en Halatte (France); Caracena, A.B. [Universidad de Murcia, Dept. de Ingenieria Quimica-Murcia (Spain)

    2001-07-01

    Benzene is among the gasoline components and is airborne by vehicular traffic. It is a myelo-toxic and leukaemia-inducing compound. The risk level, expressed as myeloid leukaemia cases increment estimate among the population not professionally exposed to benzene, has been stated to range 3.8 to 7.5 cases every million people exposed during the lifetime to 1 {mu}g/m{sup 3}. All the estimates deal with exposure, not with environmental concentration. Since the two parameters can be not coincident, the citizens' risk level, which depends on actual exposure, can not be simply estimated by means of urban pollution. Therefore, once a socially acceptable exposure risk level is stated by a political decision, one can set a limiting value for benzene concentration in urban air only if the relationship between personal exposure and urban pollution is known. We find the citizens' exposure level, whatever their occupation or the fraction of time spent outdoors, is higher than urban average level and is equal, on average in Europe, to twice its value. To establish this relationship, six towns and a sample of their citizens and their homes have undergone environmental monitoring for an entire year. The towns were distributed among the Northern, Central and Southern European countries, comprising a wide range of different lifestyles, climates and development features. (authors)

  7. Effect of repeated benzene inhalation exposures on benzene metabolism, binding to hemoglobin, and induction of micronuclei

    International Nuclear Information System (INIS)

    Sabourin, P.J.; Sun, J.D.; MacGregor, J.T.; Wehr, C.M.; Birnbaum, L.S.; Lucier, G.; Henderson, R.F.

    1990-01-01

    Metabolism of benzene is thought to be necessary to produce the toxic effects, including carcinogenicity, associated with benzene exposure. To extrapolate from the results of rodent studies to potential health risks in man, one must know how benzene metabolism is affected by species, dose, dose rate, and repeated versus single exposures. The purpose of our studies was to determine the effect of repeated inhalation exposures on the metabolism of [14C]benzene by rodents. Benzene metabolism was assessed by characterizing and quantitating urinary metabolites, and by quantitating 14C bound to hemoglobin and micronuclei induction. F344/N rats and B6C3F1 mice were exposed, nose-only, to 600 ppm benzene or to air (control) for 6 hr/day, 5 days/week for 3 weeks. On the last day, both benzene-pretreated and control animals were exposed to 600 ppm, 14C-labeled benzene for 6 hr. Individual benzene metabolites in urine collected for 24 hr after the exposure were analyzed. There was a significant decrease in the respiratory rate of mice (but not rats) pretreated with benzene which resulted in lower levels of urinary [14C]benzene metabolites. The analyses indicated that the only effects of benzene pretreatment on the metabolite profile in rat or mouse urine were a slight shift from glucuronidation to sulfation in mice and a shift from sulfation to glucuronidation in rats. Benzene pretreatment also had no effect, in either species, on formation of [14C]benzene-derived hemoglobin adducts. Mice and rats had similar levels of hemoglobin adduct binding, despite the higher metabolism of benzene by mice. This indicates that hemoglobin adduct formation occurs with higher efficiency in rats. After 1 week of exposure to 600 ppm benzene, the frequency of micronucleated, polychromatic erythrocytes (PCEs) in mice was significantly increased

  8. Biomarkers of susceptibility following benzene exposure: influence of genetic polymorphisms on benzene metabolism and health effects.

    Science.gov (United States)

    Carbonari, Damiano; Chiarella, Pieranna; Mansi, Antonella; Pigini, Daniela; Iavicoli, Sergio; Tranfo, Giovanna

    2016-01-01

    Benzene is a ubiquitous occupational and environmental pollutant. Improved industrial hygiene allowed airborne concentrations close to the environmental context (1-1000 µg/m(3)). Conversely, new limits for benzene levels in urban air were set (5 µg/m(3)). The biomonitoring of exposure to such low benzene concentrations are performed measuring specific and sensitive biomarkers such as S-phenylmercapturic acid, trans, trans-muconic acid and urinary benzene: many studies referred high variability in the levels of these biomarkers, suggesting the involvement of polymorphic metabolic genes in the individual susceptibility to benzene toxicity. We reviewed the influence of metabolic polymorphisms on the biomarkers levels of benzene exposure and effect, in order to understand the real impact of benzene exposure on subjects with increased susceptibility.

  9. Benzene exposure and risk of lymphohaematopoietic cancers in 25 000 offshore oil industry workers

    Science.gov (United States)

    Stenehjem, J S; Kjærheim, K; Bråtveit, M; Samuelsen, S O; Barone-Adesi, F; Rothman, N; Lan, Q; Grimsrud, T K

    2015-01-01

    Background: The aim of this work was to examine the risk of lymphohaematopoietic (LH) cancer according to benzene exposure among offshore workers. Methods: Cancer registry data were used to identify 112 cancer cases diagnosed during 1999–2011 in a cohort of 24 917 Norwegian men reporting offshore work between 1965 and 1999. Analyses were conducted according to a stratified case–cohort design with a reference subcohort of 1661 workers. Cox regression was used to estimate hazard ratios with 95% confidence intervals, adjusted for other benzene exposure and smoking. Results: Most workers were exposed to benzene for benzene exposure and risk for AML, MM, and suggestively for CLL. PMID:25867262

  10. Indicators of benzene emissions and exposure in Bangkok street

    International Nuclear Information System (INIS)

    Leong, S.T.; Laortanakul, Preecha

    2003-01-01

    Ambient benzene measurements were conducted for the first time at four air monitoring sites in the Bangkok metropolitan region (BMR), from January to December 2001. Analytical results show that the mean benzene concentrations range from 42.4 μg/m 3 at the Din Daeng urban site to 15.1 μg/m 3 at the Chaeng Wattana suburban site. The monitoring results show that at a larger distance from the roadside or a higher level from the street surface, the level of benzene decreases. Analysis of the ambient benzene concentrations was carried out with reference to meteorological influences and traffic density. In traffic analysis, the combined effects of street topography and traffic flows established high impact on the overall benzene concentration in Bangkok. Statistical analysis shows good correlations of blood benzene levels and trans, trans-muconic acid with ambient benzene and demonstrated substantial exposure from traffic

  11. Evidence for non-linear metabolism at low benzene exposures? A reanalysis of data.

    Science.gov (United States)

    McNally, K; Sams, C; Loizou, G D; Jones, K

    2017-12-25

    The presence of a high-affinity metabolic pathway for low level benzene exposures of less than one part per million (ppm) has been proposed although a pathway has not been identified. The variation of metabolite molar fractions with increasing air benzene concentrations was suggested as evidence of significantly more efficient benzene metabolism at concentrations benzene concentrations (not just "low level"). In this work we undertake a further independent re-analysis of this data with a focus on the evidence for an increase in the rate of metabolism of benzene exposures of less than 1 ppm. The analysis dataset consisted of measurements of benzene and toluene from personal air samplers, and measurements of unmetabolised benzene and toluene and five metabolites (phenol hydroquinone, catechol, trans, trans-muconic acid and s-phenylmercapturic acid) from post-shift urine samples for 213 workers with an occupational exposure to benzene (and toluene) and 139 controls. Measurements from control subjects were used to estimate metabolite concentrations resulting from non-occupational sources, including environmental sources of benzene. Data from occupationally exposed subjects were used to estimate metabolite concentrations as a function of benzene exposure. Correction for background (environmental exposure) sources of metabolites was achieved through a comparison of geometric means in occupationally exposed and control populations. The molar fractions of the five metabolites as a function of benzene exposure were computed. A supra-linear relationship between metabolite concentrations and benzene exposure was observed over the range 0.1-10 ppm benzene, however over the range benzene exposures of between 0.1 and 1 ppm only a modest departure from linearity was observed. The molar fractions estimated in this work were near constant over the range 0.1-10 ppm. No evidence of high affinity metabolism at these low level exposures was observed. Our reanalysis brings in to

  12. Benzene exposure in the shoemaking industry in China, a literature survey, 1978-2004.

    Science.gov (United States)

    Wang, Laiming; Zhou, Yimei; Liang, Youxin; Wong, Otto; Armstrong, Thomas; Schnatter, A Robert; Wu, Qiangen; Fang, Jinbin; Ye, Xibiao; Fu, Hua; Irons, Richard D

    2006-11-01

    This article presents a summary of benzene exposure levels in the shoemaking industry in China reported in the Chinese medical literature between 1978 and 2004. A comprehensive search identified 182 papers reporting such exposure data. These papers could be classified into two categories: benzene poisoning case reports and industrial hygiene surveys. From each paper, the following information was abstracted whenever available: location and year of occurrence, occupation and/or task involved, benzene content in adhesives/solvents, work environment, working conditions, working hours, diagnosis, and air monitoring data of benzene. A total of 333 benzene measurements (88 averages, 116 minimums, 129 maximums) in the shoemaking industry were reported in the 182 papers identified. The data were analyzed in terms of geographical location, time period, type of ownership (state, township, or foreign), type of report (benzene poisoning reports vs. industrial hygiene surveys), and job title (work activity) or process. The reported data covered a wide range; some measurements were in excess of 4500 mg/m(3). Thirty-five percent of the reported benzene concentrations were below 40 mg/m(3), which was the national occupational exposure limit (OEL) for benzene between 1979 and 2001. The remaining 65% measurements, which exceeded the national OEL in effect at the time, and were distributed as follows: 40-100 mg/m(3), 11%; 100-300 mg/m(3), 21%; 300-500 mg/m(3), 13%; and 500+ mg/m(3), 20%. However, only 24% of the reported measurements after 2002 were below 6 mg/m(3), i.e., Permissible Concentration-Time Weighted Average (PC-TWA) and 10 mg/m(3), i.e., Permissible Concentration-Short Term Exposure Limit (PC-STEL), the newly amended benzene OELs in effect after May 2002. The data demonstrated that the majority of the facilities in the shoemaking industry reported in the literature were not in compliance of the OEL for benzene in effect at the time. Overall, the data show a clear downward

  13. Benzene exposure is associated with cardiovascular disease risk.

    Directory of Open Access Journals (Sweden)

    Wesley Abplanalp

    Full Text Available Benzene is a ubiquitous, volatile pollutant present at high concentrations in toxins (e.g. tobacco smoke known to increase cardiovascular disease (CVD risk. Despite its prevalence, the cardiovascular effects of benzene have rarely been studied. Hence, we examined whether exposure to benzene is associated with increased CVD risk. The effects of benzene exposure in mice were assessed by direct inhalation, while the effects of benzene exposure in humans was assessed in 210 individuals with mild to high CVD risk by measuring urinary levels of the benzene metabolite trans,trans-muconic acid (t,t-MA. Generalized linear models were used to assess the association between benzene exposure and CVD risk. Mice inhaling volatile benzene had significantly reduced levels of circulating angiogenic cells (Flk-1+/Sca-1+ as well as an increased levels of plasma low-density lipoprotein (LDL compared with control mice breathing filtered air. In the human cohort, urinary levels of t,t-MA were inversely associated several populations of circulating angiogenic cells (CD31+/34+/45+, CD31+/34+/45+/AC133-, CD34+/45+/AC133+. Although t,t-MA was not associated with plasma markers of inflammation or thrombosis, t,t-MA levels were higher in smokers and in individuals with dyslipidemia. In smokers, t,t-MA levels were positively associated with urinary metabolites of nicotine (cotinine and acrolein (3-hydroxymercapturic acid. Levels of t,t-MA were also associated with CVD risk as assessed using the Framingham Risk Score and this association was independent of smoking. Thus, benzene exposure is associated with increased CVD risk and deficits in circulating angiogenic cells in both smokers and non-smokers.

  14. Alternatives for Benzene in the Extraction of Bitumen Fume from Exposure Sample Media.

    Science.gov (United States)

    Sutter, Benjamin; Ravera, Christel; Hussard, Caroline; Langlois, Eddy

    2016-01-01

    Benzene is frequently used to extract collected bitumen fumes from personal sampler substrates. However, this solvent is particularly dangerous because of its carcinogenicity (group 1 of the International Agency for Research on Cancer classification). Therefore, to prevent the exposure of laboratory technicians to benzene during the fume extraction step from samplers, a compromise had to be found to identify a less toxic solvent with the same extraction capacity. To compare the extraction capacities of selected solvents, bitumen fumes were generated in the laboratory from three different batches of road surfacing bitumen collected on dedicated bitumen fume samplers. The samplers were then extracted by benzene and the solvents tested. Of 11 selected solvents less toxic than benzene and used in studies on bitumen and bitumen fume analyses, n-hexane and n-heptane were identified as alternatives to benzene. In particular, the results demonstrated that n-heptane was the best candidate solvent for benzene replacement, due to its extraction efficiency comparable to benzene for the three bitumen fumes tested and its low toxicity, which is highly compatible with benzene replacement. © The Author 2015. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

  15. Environmental, Occupational Exposures to Benzene and Cancer: a Meta –analysis

    Directory of Open Access Journals (Sweden)

    Onny Setiani

    2015-12-01

    Full Text Available ABSTRACT Background: Many epidemiological studies have been able to address the relationships between benzene exposure in the environment  and  the level of risk. Incidence has risen in industrialized countries since the 1960s and is highly and rapidly fatal and represent the fifth leading cause of deaths from cancer  and 50%-100%  more  common in men than women. To identify, appraising and synthesizing  the risk of cancer from benzene exposure in environment or workplace,  a meta analysis is conducted. Method: Epidemiological studies were identified through a computerized Medline and search on follow up and case control studies.  The risk were identified as Standardized Mortality Ratios (SMRs, Standardized Incidence Ratios (SIRs, Relative Risk (RR and Odd Ratio (OR.   Data extraction covered characteristic of the study (publication year, country, study type, case definition, sources of cases, reference population, follow up period, risk measures and  risk estimates. The extracted data were checked for consistency and entered into a database and checked for correctness. Summary of  relative risk was calculated from log(RR and log(upper and lower limit of 95% CI of log RR. SE and weight of all studies were estimated by fixed effect model. Results: The identified studies  were industrial-based (n=6, community-based (n=2,  and multicentre hospital-based study (n=2. RR of each study were also show benzene exposure was favour to risk of malignancy. This findings indicated workers who were exposed to benzene have risk to get malignancy 2 times higher than  person who were not exposed to benzene. The excess risk found for Benzene was based on 8 population that were exposed with benzene from oil or petroleum  industry. The risk of soft tissue carcinoma due to benzene exposure was highest  with RR=15,59 (95% CI= 1.74-139.3.  The lowest risk was  stomach carcinoma RR 2,51  (95% CI= 1,60-2,94 and hemopoetic malignancy in general with RR

  16. Characterization of changes in gene expression and biochemical pathways at low levels of benzene exposure.

    Directory of Open Access Journals (Sweden)

    Reuben Thomas

    Full Text Available Benzene, a ubiquitous environmental pollutant, causes acute myeloid leukemia (AML. Recently, through transcriptome profiling of peripheral blood mononuclear cells (PBMC, we reported dose-dependent effects of benzene exposure on gene expression and biochemical pathways in 83 workers exposed across four airborne concentration ranges (from 10 ppm compared with 42 subjects with non-workplace ambient exposure levels. Here, we further characterize these dose-dependent effects with continuous benzene exposure in all 125 study subjects. We estimated air benzene exposure levels in the 42 environmentally-exposed subjects from their unmetabolized urinary benzene levels. We used a novel non-parametric, data-adaptive model selection method to estimate the change with dose in the expression of each gene. We describe non-parametric approaches to model pathway responses and used these to estimate the dose responses of the AML pathway and 4 other pathways of interest. The response patterns of majority of genes as captured by mean estimates of the first and second principal components of the dose-response for the five pathways and the profiles of 6 AML pathway response-representative genes (identified by clustering exhibited similar apparent supra-linear responses. Responses at or below 0.1 ppm benzene were observed for altered expression of AML pathway genes and CYP2E1. Together, these data show that benzene alters disease-relevant pathways and genes in a dose-dependent manner, with effects apparent at doses as low as 100 ppb in air. Studies with extensive exposure assessment of subjects exposed in the low-dose range between 10 ppb and 1 ppm are needed to confirm these findings.

  17. Characterization of Changes in Gene Expression and Biochemical Pathways at Low Levels of Benzene Exposure

    Science.gov (United States)

    Thomas, Reuben; Hubbard, Alan E.; McHale, Cliona M.; Zhang, Luoping; Rappaport, Stephen M.; Lan, Qing; Rothman, Nathaniel; Vermeulen, Roel; Guyton, Kathryn Z.; Jinot, Jennifer; Sonawane, Babasaheb R.; Smith, Martyn T.

    2014-01-01

    Benzene, a ubiquitous environmental pollutant, causes acute myeloid leukemia (AML). Recently, through transcriptome profiling of peripheral blood mononuclear cells (PBMC), we reported dose-dependent effects of benzene exposure on gene expression and biochemical pathways in 83 workers exposed across four airborne concentration ranges (from 10 ppm) compared with 42 subjects with non-workplace ambient exposure levels. Here, we further characterize these dose-dependent effects with continuous benzene exposure in all 125 study subjects. We estimated air benzene exposure levels in the 42 environmentally-exposed subjects from their unmetabolized urinary benzene levels. We used a novel non-parametric, data-adaptive model selection method to estimate the change with dose in the expression of each gene. We describe non-parametric approaches to model pathway responses and used these to estimate the dose responses of the AML pathway and 4 other pathways of interest. The response patterns of majority of genes as captured by mean estimates of the first and second principal components of the dose-response for the five pathways and the profiles of 6 AML pathway response-representative genes (identified by clustering) exhibited similar apparent supra-linear responses. Responses at or below 0.1 ppm benzene were observed for altered expression of AML pathway genes and CYP2E1. Together, these data show that benzene alters disease-relevant pathways and genes in a dose-dependent manner, with effects apparent at doses as low as 100 ppb in air. Studies with extensive exposure assessment of subjects exposed in the low-dose range between 10 ppb and 1 ppm are needed to confirm these findings. PMID:24786086

  18. Benzene exposure among auto-repair workers from workplace ambience: a pioneer study from Pakistan.

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    Kamal, Atif; Rashid, Audil

    2014-10-01

    In Pakistan, the reports on benzene exposure among workers in chemical industries are almost non-existing due to limited research work in the field of exposure science. This study aimed to investigate such exposure in a widely adopted occupation in Rawalpindi city. In this cross-sectional study, 60 blood samples (N = 20/group) of mechanics (MCs), spray painters (PNs) and control participants (CN) were analyzed. The socio-economic and demographic information of workers and that of workplaces was documented using a short questionnaire. We identified that the workers in spray-painting occupation are highly at risk of benzene exposure. The results showed that PNs were more at risk of exposure to benzene than MCs, and this exposure was significantly correlated with long working hours (r = 0.68, p chemicals, other identified predictors of exposure included active and passive smoking, poor workplace hygiene and substandard ventilation. To mitigate workplace exposure, it is necessary to reduce working hours and encourage regular use of self-protective equipments and adoption of proper hygiene in chemical workplaces.

  19. Characterization of changes in gene expression and biochemical pathways at low levels of benzene exposure

    NARCIS (Netherlands)

    Thomas, Reuben; Hubbard, Alan E.; McHale, Cliona M.; Zhang, Luoping; Rappaport, Stephen M.; Lan, Qing; Rothman, Nathaniel; Vermeulen, Roel; Guyton, Kathryn Z.; Jinot, Jennifer; Sonawane, Babasaheb R.; Smith, Martyn T.

    2014-01-01

    Benzene, a ubiquitous environmental pollutant, causes acute myeloid leukemia (AML). Recently, through transcriptome profiling of peripheral blood mononuclear cells (PBMC), we reported dose-dependent effects of benzene exposure on gene expression and biochemical pathways in 83 workers exposed across

  20. Evaluation of inflammatory reactions and genotoxic effects after exposure of nasal respiratory epithelia to benzene.

    Science.gov (United States)

    Gosepath, Jan; Grebneva, Nina; Brieger, Juergen; Mann, Wolf J

    2003-01-01

    The aim of this study was to identify inflammatory changes as well as genotoxic effects in cultivated human respiratory epithelial cells after in vitro exposure to benzene. Primary cell cultures of nasal respiratory mucosa were exposed to synthetic air enriched with 5,000 microg/m(3) of benzene at an air/liquid interface over 8 h and then to synthetic air only over the following 24 h. Controls were continuously exposed to synthetic air over 32 h. To detect inflammatory reactions, release of prostaglandin E(2) was quantified using a competitive enzyme immunoassay. The Comet Assay was used to quantify the ratio of apoptotic cells with benzene-induced DNA fragmentation. Prostaglandin release as well as DNA fragmentation increased after 8 h of exposure and remained elevated throughout the following 24 h but did not increase in controls. High concentrations of benzene induce an inflammatory response and possibly fragmentation of DNA in respiratory epithelial cells. These findings have to be discussed with respect to possible mutagenic or carcinogenic effects of benzene in nasal respiratory cells. Copyright 2003 S. Karger AG, Basel

  1. Occupational exposure to carcinogens: Benzene, pesticides and fibers (Review).

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    Falzone, Luca; Marconi, Andrea; Loreto, Carla; Franco, Sabrina; Spandidos, Demetrios A; Libra, Massimo

    2016-11-01

    It is well known that the occupational exposure to contaminants and carcinogens leads to the development of cancer in exposed workers. In the 18th century, Percivall Pott was the first to hypothesize that chronic exposure to dust in the London chimney sweeps was associated with an increased risk of developing cancer. Subsequently a growing body of evidence indicated that other physical factors were also responsible for oncogenic mutations. Over the past decades, many carcinogens have been found in the occupational environment and their presence is often associated with an increased incidence of cancer. Occupational exposure involves several factors and the association between carcinogens, occupational exposure and cancer is still unclear. Only a fraction of factors is recognized as occupational carcinogens and for each factor, there is an increased risk of cancer development associated with a specific work activity. According to the International Agency for Research on Cancer (IARC), the majority of carcinogens are classified as 'probable' and 'possible' human carcinogens, while, direct evidence of carcinogenicity is provided in epidemiological and experimental studies. In the present review, exposures to benzene, pesticides and mineral fibers are discussed as the most important cancer risk factors during work activities.

  2. Occupational exposure to carcinogens: Benzene, pesticides and fibers

    Science.gov (United States)

    Falzone, Luca; Marconi, Andrea; Loreto, Carla; Franco, Sabrina; Spandidos, Demetrios A.; Libra, Massimo

    2016-01-01

    It is well known that the occupational exposure to contaminants and carcinogens leads to the development of cancer in exposed workers. In the 18th century, Percivall Pott was the first to hypothesize that chronic exposure to dust in the London chimney sweeps was associated with an increased risk of developing cancer. Subsequently a growing body of evidence indicated that other physical factors were also responsible for oncogenic mutations. Over the past decades, many carcinogens have been found in the occupational environment and their presence is often associated with an increased incidence of cancer. Occupational exposure involves several factors and the association between carcinogens, occupational exposure and cancer is still unclear. Only a fraction of factors is recognized as occupational carcinogens and for each factor, there is an increased risk of cancer development associated with a specific work activity. According to the International Agency for Research on Cancer (IARC), the majority of carcinogens are classified as ‘probable’ and ‘possible’ human carcinogens, while, direct evidence of carcinogenicity is provided in epidemiological and experimental studies. In the present review, exposures to benzene, pesticides and mineral fibers are discussed as the most important cancer risk factors during work activities. PMID:27748850

  3. Simultaneous exposure to ethyl benzene and noise : synergistic effects on outer hair cells

    NARCIS (Netherlands)

    Cappaert, N.L.M.; Klis, S.F.L.; Muijser, H.; Kulig, B.M.; Smoorenburg, G.F.

    2001-01-01

    The effects on hearing of simultaneous exposure to the ototoxic organic solvent ethyl benzene and broad-band noise were evaluated in rats. The effects of three ethyl benzene concentrations (0, 300 or 400 ppm) and three noise levels (95 or 105 dBlin SPL or background noise at 65 dBlin SPL) and all

  4. The immunotoxicological pattern of subchronic and chronic benzene exposure in rats.

    Science.gov (United States)

    Karaulov, Alexander V; Mikhaylova, Irina V; Smolyagin, Alexander I; Boev, Viktor M; Kalogeraki, Alexandra; Tsatsakis, Aristides M; Engin, Ayse Basak

    2017-06-05

    Exposure to benzene and its inevitable metabolites can result in deleterious effects on human health, including lymphocytopenia, hematotoxicity and cancer. However, the duration of exposure might alter the effects including immune consequences. The aim of this study was to determine whether benzene could modulate lymphocyte proliferation induced by the T cell mitogen concanavalin A, in rats, at different exposure durations. 386 Wistar rats were assigned into control and treatment groups which were subdivided into groups for 45, 90 and 135days for 0,6mL/kg of drinking water mixed benzene treatment. The percentage of CD3+, CD4+, CD8+ spleen lymphocytes was defined using the flow cytometer. Interleukin (IL)-4, IL-6, IL-10 and interferon-gamma, in supernatants of splenocyte cultures stimulated with Concanavalin A, were assessed by enzyme-linked immunosorbent assay (ELISA) technique. The decrease in the total lymphocyte and T cell counts were associated with increased benzene exposure duration. Th2-type cytokine, IL-4 significantly increased, whereas IL-6, CD4+T cells, CD4+/CD8+ ratio and CD3+ T cells decreased. Despite the positive correlation between benzene toxicity and indicated increased immune responses, 45-day exposure to benzene appeared to be the most sensitive time point for evaluating benzene cytotoxicity. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Benzene and naphthalene in air and breath as indicators of exposure to jet fuel

    OpenAIRE

    Egeghy, P; Hauf-Cabalo, L; Gibson, R; Rappaport, S

    2003-01-01

    Aims: To estimate exposures to benzene and naphthalene among military personnel working with jet fuel (JP-8) and to determine whether naphthalene might serve as a surrogate for JP-8 in studies of health effects.

  6. An overview of published benzene exposure data by industry in China, 1960-2003.

    Science.gov (United States)

    Liang, You-Xin; Wong, Otto; Armstrong, Thomas; Ye, Xi-Biao; Miao, Li-Zhuang; Zhou, Yi-Mei; Wu, Qiang-En; Qian, Hao-Jun; Fu, Hua

    2005-05-30

    This article presents an overview of occupational benzene exposures in China based on data published in Chinese medical journals. The data were derived from 384 reports of benzene poisoning or industrial hygiene surveys published in Chinese medical journals between 1960 and 2003. The following information was extracted whenever available: industry, occupation, task, date, benzene levels, sampling location, workplace descriptions and, for case reports, medical diagnosis. Each paper provided one or more sets of benzene data, each set representing a sampling location or job title with one to several measurements including, mainly, breathing zone area concentration measurements, and much less frequently personal monitoring. Two criteria based on data quality were applied to select suitable data for analyses. The selected exposure data were analyzed by industry and time period. Nine hundred five sets of benzene measurements from 72 industries were reported in the 384 papers selected for this review, and 621 sets (68.6%) presented average benzene concentrations, which covered 55 industries. The distribution of the reported average benzene exposures was skewed with a median of 51.5 mg/m3. The average benzene concentrations were below 100 mg/m3 for 406 (65%) of the 621 reported average concentrations. The medians of the reported averages in mg/m3 for the five industries with the highest exposures were: 124.8 for leather products, 98.7 for electronic devices, 75.4 for machinery, 50.4 for shoes, and 50.3 for office supplies and sports equipment manufacturing. These data describe the concentrations and changing patterns of occupational benzene exposure by industry and time period in China.

  7. Comparison of personal air benzene and urine t,t-muconic acid as a benzene exposure surrogate during turnaround maintenance in petrochemical plants.

    Science.gov (United States)

    Koh, Dong-Hee; Lee, Mi-Young; Chung, Eun-Kyo; Jang, Jae-Kil; Park, Dong-Uk

    2018-04-12

    Previous studies have shown that biomarkers of chemicals with long half-lives may be better surrogates of exposure for epidemiological analyses, leading to less attenuation of the exposure-disease association, than personal air samples. However, chemicals with short half-lives have shown inconsistent results. In the present study, we compared pairs of personal air benzene and its short-half-life urinary metabolite trans,trans-muconic acid (t,t-MA), and predicted attenuation bias of theoretical exposure-disease association. Total 669 pairs of personal air benzene and urine t,t-MA samples were taken from 474 male workers during turnaround maintenance operations held in seven petrochemical plants. Maintenance jobs were classified into 13 groups. Variance components were calculated for personal air benzene and urine t, t-MA separately to estimate the attenuation of the theoretical exposure-disease association. Personal air benzene and urine t, t-MA showed similar attenuation of the theoretical exposure-disease association. Analyses for repeated measurements showed similar results, while in analyses for values above the limits of detection (LODs), urine t, t-MA showed less attenuation of the theoretical exposure-disease association than personal air benzene. Our findings suggest that there may be no significant difference in attenuation bias when personal air benzene or urine t,t-MA is used as a surrogate for benzene exposure.

  8. Retrospective benzene exposure assessment for a multi-center case-cohort study of benzene-exposed workers in China.

    Science.gov (United States)

    Portengen, Lützen; Linet, Martha S; Li, Gui-Lan; Lan, Qing; Dores, Graça M; Ji, Bu-Tian; Hayes, Richard B; Yin, Song-Nian; Rothman, Nathaniel; Vermeulen, Roel

    2016-01-01

    Quality of exposure assessment has been shown to be related to the ability to detect risk of lymphohematopoietic disorders in epidemiological investigations of benzene, especially at low levels of exposure. We set out to build a statistical model for reconstructing exposure levels for 2898 subjects from 501 factories that were part of a nested case-cohort study within the NCI-CAPM cohort of more than 110,000 workers. We used a hierarchical model to allow for clustering of measurements by factory, workshop, job, and date. To calibrate the model we used historical routine monitoring data. Measurements below the limit of detection were accommodated by constructing a censored data likelihood. Potential non-linear and industry-specific time-trends and predictor effects were incorporated using regression splines and random effects. A partial validation of predicted exposures in 2004/2005 was performed through comparison with full-shift measurements from an exposure survey in facilities that were still open. Median cumulative exposure to benzene at age 50 for subjects that ever held an exposed job (n=1175) was 509 mg/m(3) years. Direct comparison of model estimates with measured full-shift personal exposure in the 2004/2005 survey showed moderate correlation and a potential downward bias at low (<1 mg/m(3)) exposure estimates. The modeling framework enabled us to deal with the data complexities generally found in studies using historical exposure data in a comprehensive way and we therefore expect to be able to investigate effects at relatively low exposure levels.

  9. The use of biomonitoring data in exposure and human health risk assessment: benzene case study.

    Science.gov (United States)

    Arnold, Scott M; Angerer, Juergen; Boogaard, Peter J; Hughes, Michael F; O'Lone, Raegan B; Robison, Steven H; Schnatter, A Robert

    2013-02-01

    Abstract A framework of "Common Criteria" (i.e. a series of questions) has been developed to inform the use and evaluation of biomonitoring data in the context of human exposure and risk assessment. The data-rich chemical benzene was selected for use in a case study to assess whether refinement of the Common Criteria framework was necessary, and to gain additional perspective on approaches for integrating biomonitoring data into a risk-based context. The available data for benzene satisfied most of the Common Criteria and allowed for a risk-based evaluation of the benzene biomonitoring data. In general, biomarker (blood benzene, urinary benzene and urinary S-phenylmercapturic acid) central tendency (i.e. mean, median and geometric mean) concentrations for non-smokers are at or below the predicted blood or urine concentrations that would correspond to exposure at the US Environmental Protection Agency reference concentration (30 µg/m(3)), but greater than blood or urine concentrations relating to the air concentration at the 1 × 10(-5) excess cancer risk (2.9 µg/m(3)). Smokers clearly have higher levels of benzene exposure, and biomarker levels of benzene for non-smokers are generally consistent with ambient air monitoring results. While some biomarkers of benzene are specific indicators of exposure, the interpretation of benzene biomonitoring levels in a health-risk context are complicated by issues associated with short half-lives and gaps in knowledge regarding the relationship between the biomarkers and subsequent toxic effects.

  10. The use of biomonitoring data in exposure and human health risk assessment: benzene case study

    Science.gov (United States)

    Angerer, Juergen; Boogaard, Peter J.; Hughes, Michael F.; O’Lone, Raegan B.; Robison, Steven H.; Robert Schnatter, A.

    2013-01-01

    A framework of “Common Criteria” (i.e. a series of questions) has been developed to inform the use and evaluation of biomonitoring data in the context of human exposure and risk assessment. The data-rich chemical benzene was selected for use in a case study to assess whether refinement of the Common Criteria framework was necessary, and to gain additional perspective on approaches for integrating biomonitoring data into a risk-based context. The available data for benzene satisfied most of the Common Criteria and allowed for a risk-based evaluation of the benzene biomonitoring data. In general, biomarker (blood benzene, urinary benzene and urinary S-phenylmercapturic acid) central tendency (i.e. mean, median and geometric mean) concentrations for non-smokers are at or below the predicted blood or urine concentrations that would correspond to exposure at the US Environmental Protection Agency reference concentration (30 µg/m3), but greater than blood or urine concentrations relating to the air concentration at the 1 × 10−5 excess cancer risk (2.9 µg/m3). Smokers clearly have higher levels of benzene exposure, and biomarker levels of benzene for non-smokers are generally consistent with ambient air monitoring results. While some biomarkers of benzene are specific indicators of exposure, the interpretation of benzene biomonitoring levels in a health-risk context are complicated by issues associated with short half-lives and gaps in knowledge regarding the relationship between the biomarkers and subsequent toxic effects. PMID:23346981

  11. Benzene and naphthalene in air and breath as indicators of exposure to jet fuel

    Science.gov (United States)

    Egeghy, P; Hauf-Cabalo, L; Gibson, R; Rappaport, S

    2003-01-01

    Aims: To estimate exposures to benzene and naphthalene among military personnel working with jet fuel (JP-8) and to determine whether naphthalene might serve as a surrogate for JP-8 in studies of health effects. Methods: Benzene and naphthalene were measured in air and breath of 326 personnel in the US Air Force, who had been assigned a priori into low, moderate, and high exposure categories for JP-8. Results: Median air concentrations for persons in the low, moderate, and high exposure categories were 3.1, 7.4, and 252 µg benzene/m3 air, 4.6, 9.0, and 11.4 µg benzene/m3 breath, 1.9, 10.3, and 485 µg naphthalene/m3 air, and 0.73, 0.93, and 1.83 µg naphthalene/m3 breath, respectively. In the moderate and high exposure categories, 5% and 15% of the benzene air concentrations, respectively, were above the 2002 threshold limit value (TLV) of 1.6 mg/m3. Multiple regression analyses of air and breath levels revealed prominent background sources of benzene exposure, including cigarette smoke. However, naphthalene exposure was not unduly influenced by sources other than JP-8. Among heavily exposed workers, dermal contact with JP-8 contributed to air and breath concentrations along with several physical and environmental factors. Conclusions: Personnel having regular contact with JP-8 are occasionally exposed to benzene at levels above the current TLV. Among heavily exposed workers, uptake of JP-8 components occurs via both inhalation and dermal contact. Naphthalene in air and breath can serve as useful measures of exposure to JP-8 and uptake of fuel components in the body. PMID:14634191

  12. Adverse Health Effects of Benzene Exposure Among Children Following a Flaring Incident at the British Petroleum Refinery in Texas City.

    Science.gov (United States)

    D'Andrea, Mark A; Reddy, G Kesava

    2016-03-01

    This study examined the health effects of benzene exposure among children from a flaring incident at the British Petroleum (BP) refinery in Texas City, Texas. A total of 899 children (benzene exposed, n = 641 and unexposed, n = 258), aged benzene are at a higher risk of developing both hepatic and bone marrow-related disorders. © The Author(s) 2015.

  13. Health Risk Assessment of Inhalation Exposure to Formaldehyde and Benzene in Newly Remodeled Buildings, Beijing

    Science.gov (United States)

    Huang, Lihui; Mo, Jinhan; Sundell, Jan; Fan, Zhihua; Zhang, Yinping

    2013-01-01

    Objective To assess health risks associated with inhalation exposure to formaldehyde and benzene mainly emitted from building and decoration materials in newly remodeled indoor spaces in Beijing. Methods We tested the formaldehyde and benzene concentrations in indoor air of 410 dwellings and 451 offices remodeled within the past year, in which the occupants had health concerns about indoor air quality. To assess non-carcinogenic health risks, we compared the data to the health guidelines in China and USA, respectively. To assess carcinogenic health risks, we first modeled indoor personal exposure to formaldehyde and benzene using the concentration data, and then estimated the associated cancer risks by multiplying the indoor personal exposure by the Inhalation Unit Risk values (IURs) provided by the U.S. EPA Integrated Risk Information System (U.S. EPA IRIS) and the California Office of Environmental Health Hazard Assessment (OEHHA), respectively. Results (1) The indoor formaldehyde concentrations of 85% dwellings and 67% offices were above the acute Reference Exposure Level (REL) recommended by the OEHHA and the concentrations of all tested buildings were above the chronic REL recommended by the OEHHA; (2) The indoor benzene concentrations of 12% dwellings and 32% offices exceeded the reference concentration (RfC) recommended by the U.S. EPA IRIS; (3) The median cancer risks from indoor exposure to formaldehyde and benzene were 1,150 and 106 per million (based on U.S. EPA IRIS IURs), 531 and 394 per million (based on OEHHA IURs). Conclusions In the tested buildings, formaldehyde exposure may pose acute and chronic non-carcinogenic health risks to the occupants, whereas benzene exposure may pose chronic non-carcinogenic risks to the occupants. Exposure to both compounds is associated with significant carcinogenic risks. Improvement in ventilation, establishment of volatile organic compounds (VOCs) emission labeling systems for decorating and refurbishing materials

  14. Exposure Evaluation for Benzene, Lead and Noise in Vehicle and Equipment Repair Shops

    Energy Technology Data Exchange (ETDEWEB)

    Sweeney, Lynn C. [Washington State Univ., Pullman, WA (United States)

    2013-04-01

    An exposure assessment was performed at the equipment and vehicle maintenance repair shops operating at the U. S. Department of Energy Hanford site, in Richland, Washington. The maintenance shops repair and maintain vehicles and equipment used in support of the Hanford cleanup mission. There are three general mechanic shops and one auto body repair shop. The mechanics work on heavy equipment used in construction, cranes, commercial motor vehicles, passenger-type vehicles in addition to air compressors, generators, and farm equipment. Services include part fabrication, installation of equipment, repair and maintenance work in the engine compartment, and tire and brake services. Work performed at the auto body shop includes painting and surface preparation which involves applying body filler and sanding. 8-hour time-weighted-average samples were collected for benzene and noise exposure and task-based samples were collected for lead dust work activities involving painted metal surfaces. Benzene samples were obtained using 3M™ 3520 sampling badges and were analyzed for additional volatile organic compounds. These compounds were selected based on material safety data sheet information for the aerosol products used by the mechanics for each day of sampling. The compounds included acetone, ethyl ether, toluene, xylene, VM&P naphtha, methyl ethyl ketone, and trichloroethylene. Laboratory data for benzene, VM&P naphtha, methyl ethyl ketone and trichloroethylene were all below the reporting detection limit. Airborne concentrations for acetone, ethyl ether, toluene and xylene were all less than 10% of their occupational exposure limit. The task-based samples obtained for lead dusts were submitted for a metal scan analysis to identify other metals that might be present. Laboratory results for lead dusts were all below the reporting detection limit and airborne concentration for the other metals observed in the samples were less than 10% of the occupational exposure limit

  15. Parental occupational exposure to benzene and the risk of childhood cancer: A census-based cohort study.

    Science.gov (United States)

    Spycher, Ben Daniel; Lupatsch, Judith Eva; Huss, Anke; Rischewski, Johannes; Schindera, Christina; Spoerri, Adrian; Vermeulen, Roel; Kuehni, Claudia Elisabeth

    2017-11-01

    Previous studies on occupational exposures in parents and cancer risks in their children support a link between solvents and paints with childhood leukaemia. Few studies have focused specifically on benzene. To examine whether parental occupational exposure to benzene is associated with an increased cancer risk in a census-based cohort of children. From a census-based cohort study in Switzerland, we included children aged benzene using a job exposure matrix. We identified incident cancer cases through record linkage with the Swiss Childhood Cancer Registry. We fitted Cox proportional-hazards models to assess associations between exposures and the following outcomes: any cancer, leukaemia, acute lymphoid leukaemia (ALL), acute myeloid leukaemia (AML), lymphoma, non-Hodgkin lymphoma, central nervous system (CNS) tumours, and glioma. We adjusted models for a range of socio-economic, perinatal and environmental factors. Analyses of maternal (paternal) exposure were based on 9.0 (13.2)millionperson years at risk and included 1004 (1520) cases of cancer, of which 285 (438) had leukaemia, 186 (281) lymphoma, 227 (339) a CNS tumour. Maternal exposure was associated with an increased risk of childhood leukaemia (hazard ratio 1.73, 95% CI 1.12-2.67) and ALL (1.88, 1.16-3.04). We found little evidence of an association for other outcomes or for paternal exposure. Adjusting for potential confounders did not materially affect the results. This nationwide cohort study suggests an increased risk of leukaemia among children whose mothers were exposed to benzene at work. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Dermal exposure assessment to benzene and toluene using charcoal cloth pads

    NARCIS (Netherlands)

    Joode, De B.V.; Tielemans, E.; Vermeulen, R.; Wegh, H.C.P.; Kromhout, H.

    2005-01-01

    Charcoal cloth pads have been used to assess volatile chemicals on the skin in a laboratory setting; however, they have not yet been applied to measure dermal exposure in occupational settings. This study aimed at evaluating whether charcoal pads can be used to assess dermal exposure to benzene and

  17. Low personal exposure to benzene and 1,3-butadiene in the Swedish petroleum refinery industry.

    Science.gov (United States)

    Almerud, Pernilla; Akerstrom, M; Andersson, E M; Strandberg, B; Sallsten, G

    2017-10-01

    Petroleum refinery workers are exposed to the carcinogens benzene and 1,3-butadiene. Declining exposures have been reported internationally but information on current exposure in the Swedish refinery industry is limited. The aim was to examine refinery workers' personal exposure to benzene and 1,3-butadiene and increase awareness of exposure conditions by collaboration with involved refineries. Altogether 505 repeated personal exposure measurements were performed among workers at two refineries. Full-shift measurements were conducted in different exposure groups using Perkin Elmer diffusive samplers filled with Carbopack X. Mean levels were calculated using mixed-effects models. A large fraction of measurements below the limit of detection (LOD) required imputation of computer-generated data. Mean benzene exposure among process technicians was 15.3 µg/m 3 (95% CI 10.4-22.5 µg/m 3 ) and 13.7 µg/m 3 (95% CI 8.3-22.7 µg/m 3 ) for Refinery 1 and 2, respectively. Process technicians working outdoors had higher exposure than maintenance workers (20.7 versus 5.9 µg/m 3 , p butadiene exposure was low, 5.4 and 1.8 µg/m 3 , respectively. The total variation was generally attributed to within-worker variability. Low benzene and 1,3-butadiene levels were found among refinery workers. Mean benzene exposure was about 1% of the Swedish occupational limit (1500 µg/m 3 ) and for 1,3-butadiene, exposure was even lower. A large fraction of values below the LOD can be managed by carefully modelled, computer-generated data.

  18. An analysis of violations of Osha's (1987) occupational exposure to benzene standard.

    Science.gov (United States)

    Williams, Pamela R D

    2014-01-01

    The Occupational Safety and Health Administration (OSHA), which was formed by the Occupational Safety and Health Act of 1970 (OSH Act), establishes enforceable health and safety standards in the workplace and issues violations and penalties for non-compliance with these standards. The purpose of the current study was to evaluate the number and type of violations of the OSHA (1987) Occupational Exposure to Benzene Standard. Violations of the OSHA Hazard Communication Standard (HCS), particularly those that may pertain to specific provisions of the benzene standard, were also assessed. All analyses were based on OSHA inspection data that have been collected since the early 1970s and that are publicly available from the U.S. Department of Labor enforcement website. Analysis of these data shows that fewer than a thousand OSHA violations of the benzene standard have been issued over the last 25+ years. The results for benzene are in contrast to those for some other toxic and hazardous substances that are regulated by OSHA, such as blood-borne pathogens, lead, and asbestos, for which there have been issued tens of thousands of OSHA violations. The number of benzene standard violations also varies by time period, standard provision, industry sector, and other factors. In particular, the greatest number of benzene standard violations occurred during the late 1980s to early/mid 1990s, soon after the 1987 final benzene rule was promulgated. The majority of benzene standard violations also pertain to noncompliance with specific provisions and subprovisions of the standard dealing with initial exposure monitoring requirements, the communication of hazards to employees, and medical surveillance programs. Only a small fraction of HCS violations are attributed, at least in part, to potential benzene hazards in the workplace. In addition, most benzene standard violations are associated with specific industries within the manufacturing sector where benzene or benzene

  19. Anaerobic benzene degradation under denitrifying conditions: Peptococcaceae was identified as dominant benzene degrader by Stable Isotope Probing (SIP)

    NARCIS (Netherlands)

    Zaan, van der B.M.; Talarico Saia, F.; Plugge, C.M.; Vos, de W.M.; Smidt, H.; Stams, A.J.M.; Langenhoff, A.A.M.; Gerritse, J.

    2012-01-01

    An anaerobic microbial community was enriched in a chemostat that was operated for more than 8 years with benzene and nitrate as electron acceptor. The coexistence of multiple species in the chemostat and the presence of a biofilm, led to the hypothesis that benzene-degrading species coexist in a

  20. Managing Exposure to Benzene and Total Petroleum Hydrocarbons at Two Oil Refineries 1977-2014.

    Science.gov (United States)

    Tuomi, Tapani; Veijalainen, Henna; Santonen, Tiina

    2018-01-24

    Air concentrations of and inhalation exposure to total petroleum hydrocarbons (TPH) and benzene was monitored separately at two oil refineries from 1977 to 2014. Prevention policies and control measures that may explain changes were surveyed. The aim was to evaluate how the application of of Occupational Health and Safety Assessment Series OHSAS 18001.04 principles as well as Environmental protection Agency EPA and European Oil Company Organisation for Environment, Health and Safety CONCAWE practices have influenced air concentrations. Benzene air concentrations declined in 11 of 17 units, six of which were associated with declining exposures. Benzene air concentrations declined across all units on average by 46%. This amounts to an average yearly decline of 1.7%. TPH air concentrations declined in 10 of 17 units, seven of which were associated with declining exposures. The average decline in TPH air concentrations was 49%, corresponding to 1.3% per year. As a result, average working day exposure in 10 of 17 units have declined significantly and today, benzene and TPH exposure in most units are well below 10% of the current Occupational Exposure Limit (OEL 8h :s). A decline in air concentrations have coincided with consistent implementation of control measures. Such measures include on-line monitoring of leaks; benzene recovery; floating container roofs; improved valves and seals; hermetic pumps; recovery of loading gases and instalment of torches in terminals; cutback in coke combustion; a new production line spanning directly from the dock to aromatics production; and recovery of loading gases in the doc. Other tools in exposure management include personal leak monitors, on-line measurements, monitoring campaigns, risk assessment, and availability and user training of protective equipment. However, improvements are still needed. Hydrocarbon or benzene air concentrations have not declined in 8 of 17 units, in some of which concentrations exceed 10% of the relevant

  1. Managing Exposure to Benzene and Total Petroleum Hydrocarbons at Two Oil Refineries 1977–2014

    Science.gov (United States)

    Tuomi, Tapani; Veijalainen, Henna; Santonen, Tiina

    2018-01-01

    Air concentrations of and inhalation exposure to total petroleum hydrocarbons (TPH) and benzene was monitored separately at two oil refineries from 1977 to 2014. Prevention policies and control measures that may explain changes were surveyed. The aim was to evaluate how the application of of Occupational Health and Safety Assessment Series OHSAS 18001.04 principles as well as Environmental protection Agency EPA and European Oil Company Organisation for Environment, Health and Safety CONCAWE practices have influenced air concentrations. Benzene air concentrations declined in 11 of 17 units, six of which were associated with declining exposures. Benzene air concentrations declined across all units on average by 46%. This amounts to an average yearly decline of 1.7%. TPH air concentrations declined in 10 of 17 units, seven of which were associated with declining exposures. The average decline in TPH air concentrations was 49%, corresponding to 1.3% per year. As a result, average working day exposure in 10 of 17 units have declined significantly and today, benzene and TPH exposure in most units are well below 10% of the current Occupational Exposure Limit (OEL8h:s). A decline in air concentrations have coincided with consistent implementation of control measures. Such measures include on-line monitoring of leaks; benzene recovery; floating container roofs; improved valves and seals; hermetic pumps; recovery of loading gases and instalment of torches in terminals; cutback in coke combustion; a new production line spanning directly from the dock to aromatics production; and recovery of loading gases in the doc. Other tools in exposure management include personal leak monitors, on-line measurements, monitoring campaigns, risk assessment, and availability and user training of protective equipment. However, improvements are still needed. Hydrocarbon or benzene air concentrations have not declined in 8 of 17 units, in some of which concentrations exceed 10% of the relevant

  2. Managing Exposure to Benzene and Total Petroleum Hydrocarbons at Two Oil Refineries 1977–2014

    Directory of Open Access Journals (Sweden)

    Tapani Tuomi

    2018-01-01

    Full Text Available Air concentrations of and inhalation exposure to total petroleum hydrocarbons (TPH and benzene was monitored separately at two oil refineries from 1977 to 2014. Prevention policies and control measures that may explain changes were surveyed. The aim was to evaluate how the application of of Occupational Health and Safety Assessment Series OHSAS 18001.04 principles as well as Environmental protection Agency EPA and European Oil Company Organisation for Environment, Health and Safety CONCAWE practices have influenced air concentrations. Benzene air concentrations declined in 11 of 17 units, six of which were associated with declining exposures. Benzene air concentrations declined across all units on average by 46%. This amounts to an average yearly decline of 1.7%. TPH air concentrations declined in 10 of 17 units, seven of which were associated with declining exposures. The average decline in TPH air concentrations was 49%, corresponding to 1.3% per year. As a result, average working day exposure in 10 of 17 units have declined significantly and today, benzene and TPH exposure in most units are well below 10% of the current Occupational Exposure Limit (OEL8h:s. A decline in air concentrations have coincided with consistent implementation of control measures. Such measures include on-line monitoring of leaks; benzene recovery; floating container roofs; improved valves and seals; hermetic pumps; recovery of loading gases and instalment of torches in terminals; cutback in coke combustion; a new production line spanning directly from the dock to aromatics production; and recovery of loading gases in the doc. Other tools in exposure management include personal leak monitors, on-line measurements, monitoring campaigns, risk assessment, and availability and user training of protective equipment. However, improvements are still needed. Hydrocarbon or benzene air concentrations have not declined in 8 of 17 units, in some of which concentrations exceed 10

  3. Evaluating Occupational Exposure to Carcinogenic Volatile Organic Compounds in an Oil-Dependent Chemical Industry: a Case Study on Benzen and Epichlorohydrin

    Directory of Open Access Journals (Sweden)

    Amir Reza Negahban

    2014-04-01

    Full Text Available Background & Objectives: Exposure of workers to carcinogenic compounds in chemical industries during a long period might cause irreversible health effects. This study evaluated workers exposure to benzene and epichlorohydrin in breathing air in one of the oil-dependent chemical industries of Iran. Methods: This descriptive-analytic study was performed in one of the oil-dependent chemical industries of south of Iran, winter, 2012. A total of 173 workers were examined in this study. NIOSH 1501 and 1010 methods were used to assess personal exposure to benzene and epichlorohydrin, correspondingly. Collected samples were analyzed with gas chromatography-mass spectrophotometry method. Results: Among 346 collected samples, benzene was identified in all cases (100% and epichlorohydrin in 156 samples (45%. A significant difference was found in the mean of exposure to benzene and epichlorohydrin in various workshops (Pvalue 0.05. Conclusion: It seems that work nature of employees in chemical industry affects their exposure to volatile organic compounds in workplace. According to the results, due to the proximity of compounds concentration to the action level, especially benzene and also the workers exposure to less than the maximum limit in the long-term, reducing exposure through appropriate control measures are necessary.

  4. Benzene exposure assessed by metabolite excretion in Estonian oil shale mineworkers: influence of glutathione s-transferase polymorphisms

    DEFF Research Database (Denmark)

    Sørensen, Mette; Poole, Jason; Autrup, Herman

    2004-01-01

    Measurement of urinary excretion of the benzene metabolites S-phenylmercapturic acid (S-PMA) and trans,trans-muconic acid (t,t-MA) has been proposed for assessing benzene exposure, in workplaces with relatively high benzene concentrations. Excretion of S-PMA and t,t-MA in underground workers...... the last shift of the week. Personal benzene exposure was 114 +/- 35 mug/m(3) in surface workers (n = 15) and 190 +/- 50 mug/m(3) in underground workers (n = 15) in measurements made prior to the study. We found t,t-MA excretion to be significantly higher in underground workers after the end of shifts 1...... of benzene metabolites as biomarkers for assessment of exposure at modest levels and warrant for further investigations of health risks of occupational benzene exposure in shale oil mines....

  5. Exposure to benzene at work and the risk of leukemia: a systematic review and meta-analysis

    Directory of Open Access Journals (Sweden)

    Pukkala Eero

    2010-06-01

    Full Text Available Abstract Background A substantial number of epidemiologic studies have provided estimates of the relation between exposure to benzene at work and the risk of leukemia, but the results have been heterogeneous. To bridge this gap in knowledge, we synthesized the existing epidemiologic evidence on the relation between occupational exposure to benzene and the risk of leukemia, including all types combined and the four main subgroups acute myeloid leukemia (AML, acute lymphocytic leukemia (ALL, chronic lymphocytic leukemia (CLL, and chronic myeloid leukemia (CML. Methods A systematic literature review was carried out using two databases 'Medline' and 'Embase' from 1950 through to July 2009. We selected articles which provided information that can be used to estimate the relation between benzene exposure and cancer risk (effect size. Results In total 15 studies were identified in the search, providing 16 effect estimates for the main analysis. The summary effect size for any leukemia from the fixed-effects model was 1.40 (95% CI, 1.23-1.57, but the study-specific estimates were strongly heterogeneous (I2 = 56.5%, Q stat = 34.47, p = 0.003. The random-effects model yielded a summary- effect size estimate of 1.72 (95% CI, 1.37-2.17. Effect estimates from 9 studies were based on cumulative exposures. In these studies the risk of leukemia increased with a dose-response pattern with a summary-effect estimate of 1.64 (95% CI, 1.13-2.39 for low ( 100 ppm-years. In a meta-regression, the trend was statistically significant (P = 0.015. Use of cumulative exposure eliminated heterogeneity. The risk of AML also increased from low (1.94, 95% CI, 0.95-3.95, medium (2.32, 95% CI, 0.91-5.94 to high exposure category (3.20, 95% CI, 1.09-9.45, but the trend was not statistically significant. Conclusions Our study provides consistent evidence that exposure to benzene at work increases the risk of leukemia with a dose-response pattern. There was some evidence of an

  6. Occupational Exposure to Benzene and Non-Hodgkin Lymphoma in a Population-Based Cohort: The Shanghai Women's Health Study.

    Science.gov (United States)

    Bassig, Bryan A; Friesen, Melissa C; Vermeulen, Roel; Shu, Xiao-Ou; Purdue, Mark P; Stewart, Patricia A; Xiang, Yong-Bing; Chow, Wong-Ho; Zheng, Tongzhang; Ji, Bu-Tian; Yang, Gong; Linet, Martha S; Hu, Wei; Zhang, Heping; Zheng, Wei; Gao, Yu-Tang; Rothman, Nathaniel; Lan, Qing

    2015-10-01

    The association between benzene exposure and non-Hodgkin lymphoma (NHL) has been the subject of debate as a result of inconsistent epidemiologic evidence. An International Agency for Research on Cancer (IARC) working group evaluated benzene in 2009 and noted evidence for a positive association between benzene exposure and NHL risk. We evaluated the association between occupational benzene exposure and NHL among 73,087 women enrolled in the prospective population-based Shanghai Women's Health Study. Benzene exposure estimates were derived using a previously developed exposure assessment framework that combined ordinal job-exposure matrix intensity ratings with quantitative benzene exposure measurements from an inspection database of Shanghai factories collected between 1954 and 2000. Associations between benzene exposure metrics and NHL (n = 102 cases) were assessed using Cox proportional hazard models, with study follow-up occurring from December 1996 through December 2009. Women ever exposed to benzene had a significantly higher risk of NHL [hazard ratio (HR) = 1.87, 95% CI: 1.19, 2.96]. Compared with unexposed women, significant trends in NHL risk were observed for increasing years of benzene exposure (p(trend) = 0.006) and increasing cumulative exposure levels (p(trend) = 0.005), with the highest duration and cumulative exposure tertiles having a significantly higher association with NHL (HR = 2.07, 95% CI: 1.07, 4.01 and HR = 2.16, 95% CI: 1.17, 3.98, respectively). Our findings, using a population-based prospective cohort of women with diverse occupational histories, provide additional evidence that occupational exposure to benzene is associated with NHL risk.

  7. Investigating the effects of in utero benzene exposure on epigenetic modifications in maternal and fetal CD-1 mice

    International Nuclear Information System (INIS)

    Philbrook, Nicola A.; Winn, Louise M.

    2015-01-01

    Exposure to the ubiquitous environmental pollutant benzene is positively correlated with leukemia in adults and may be associated with childhood leukemia following in utero exposure. While numerous studies implicate oxidative stress and DNA damage as playing a role in benzene-mediated carcinogenicity, emerging evidence suggests that alterations in epigenetic regulations may be involved. The present study aimed to determine whether DNA methylation and/or various histone modifications were altered following in utero benzene exposure in CD-1 mice. Global DNA methylation and promoter-specific methylation of the tumor suppressor gene, p15, were assessed. Additionally, levels of acetylated histones H3, H4, and H3K56, as well as methylated histones H3K9 and H3K27 were assessed by Western blotting. A significant decrease in global DNA methylation of maternal bone marrow was observed following benzene exposure; however no effect on global DNA methylation was detected in fetal livers. Additionally, no effect of benzene exposure was observed on p15 promoter methylation or any measured histone modifications in both maternal bone marrow and fetal livers. These results suggest that the methodology used in the present study did not reveal alterations in DNA methylation and histone modifications following in utero exposure to benzene; however further experimentation investigating these modifications at the whole genome/epigenome level, as well as at later stages of benzene-induced carcinogenesis, are warranted. - Highlights: • Benzene exposure in pregnant mice decreased global DNA methylation in maternal bone marrow. • Benzene exposure in pregnant mice had no effect on global DNA methylation in fetal livers. • No effect of benzene exposure was observed on p15 promoter methylation. • No effect of benzene on measured histone modifications in both maternal bone marrow and fetal livers was observed.

  8. Retrospective benzene and total hydrocarbon exposure assessment for a petroleum marketing and distribution worker epidemiology study.

    Science.gov (United States)

    Armstrong, T W; Pearlman, E D; Schnatter, A R; Bowes, S M; Murray, N; Nicolich, M J

    1996-04-01

    A quantitative exposure-estimating algorithm for benzene and total hydrocarbons was developed for a case control study of petroleum marketing and distribution workers. The algorithm used a multiplicative model to adjust recently measured quantitative exposure data to past scenarios for which representative exposure measurement data did not exist. This was accomplished through the development of exposure modifiers to account for differences in the workplace, the materials handled, the environmental conditions, and the tasks performed. Values for exposure modifiers were obtained empirically and through physical/chemical relationships. Dates for changes that altered exposure potential were obtained from archive records, retired employee interviews, and from current operations personnel. Exposure modifiers were used multiplicatively, adjusting available measured data to represent the relevant exposure scenario and time period. Changes in exposure modifiers translated to step changes in exposure estimates. Though limited by availability of data, a validation exercise suggested that the algorithm provided accurate exposure estimates for benzene (compared with measured data in industrial hygiene survey reports); the estimates generally differed by an average of less than 20% from the measured values. This approach is proposed to quantify exposures retrospectively where there are sufficient data to develop reliable current era estimates and where a historical accounting of key exposure modifiers can be developed, but where there are insufficient historic exposure measurements to directly assess historic exposures.

  9. Population exposure to benzene: One day cross-sections in six European cities

    Science.gov (United States)

    Ballesta, Pascual Pérez; Field, Robert A.; Connolly, Richard; Cao, Natale; Baeza Caracena, Antonia; De Saeger, Emile

    This paper describes the experimental methodology and basic results of the PEOPLE project (Population Exposure to Air Pollutants in Europe). Simultaneous diffusive measurements of outdoor, indoor and human exposure benzene concentrations were made during one day campaigns. Six cities were assessed, namely: Brussels and Lisbon (22 October 2002), Bucharest and Ljubljana (27 May 2003), Madrid (3 December 2003) and Dublin (28 April 2004). In general, human exposure to benzene was higher than concentrations reported at urban background monitoring sites. Traffic was the dominant source of benzene in all the six cities that were studied. The highest exposure levels from the commuting groups were car users. The control group, with no influence from commuting or smoking, reported concentrations closer to the background level of the city. The smoking group had the highest level of exposure. The level of exposure of school children was similar to that of the commuting groups. Indoor locations that were influenced by smoking sources, or with free access to busy streets, reported relatively high concentrations. The highest indoor concentrations were measured in bars and inside motor vehicles. When considering the six cities together, a linear relationship was evident between ambient levels and human exposure. Daily median values of human exposure for non-smoking commuters were 1.5 times the level of urban background and 0.6 times the maximum outdoor value (hotspot).

  10. Biomonitoring of benzene and 1,3-butadiene exposure and early biological effects in traffic policemen.

    Science.gov (United States)

    Arayasiri, Manaswee; Mahidol, Chulabhorn; Navasumrit, Panida; Autrup, Herman; Ruchirawat, Mathuros

    2010-09-15

    The objective of this study was to determine benzene and 1,3-butadiene exposure through ambient air and personal air monitoring, as well as through biomarkers of exposure, and to evaluate the potential health risk of exposure through the use of biomarkers of early biological effects in central Bangkok traffic policemen. Ambient air concentrations of benzene and 1,3-butadiene at the roadsides were significantly higher than in police offices used as control sites (pbutadiene (median 3.08 microg/m(3)) than office policemen (median 6.17 microg/m(3) for benzene and 0.37 microg/m(3) for 1,3-butadiene) (pbutadiene metabolite, monohydroxy-butenyl mercapturic acid. Biomarkers of early biological effects, 8-hydroxy-2'-deoxyguanosine in leukocytes (8-OHdG), DNA-strand breaks, and DNA-repair capacity, measured as an increase in gamma ray-induced chromosome aberrations were significantly higher in traffic policemen than controls (pbutadiene exposure were significantly associated with 8-OHdG and olive tail moment at pbutadiene on DNA damage. These results indicated that traffic policemen, who are exposed to benzene and 1,3-butadiene at the roadside in central Bangkok, are potentially at a higher risk for development of diseases such as cancer than office policemen. Copyright 2010 Elsevier B.V. All rights reserved.

  11. Resolving uncertainty in the spatial relationships between passive benzene exposure and risk of non-Hodgkin lymphoma.

    Science.gov (United States)

    Switchenko, Jeffrey M; Bulka, Catherine; Ward, Kevin; Koff, Jean L; Bayakly, A Rana; Ryan, P Barry; Waller, Lance A; Flowers, Christopher R

    2016-04-01

    Benzene is a known occupational carcinogen associated with increased risk of hematologic cancers, but the relationships between quantity of passive benzene exposure through residential proximity to toxic release sites, duration of exposure, lag time from exposure to cancer development, and lymphoma risk remain unclear. We collected release data through the Environmental Protection Agency's Toxics Release Inventory (TRI) from 1989 to 2003, which included location of benzene release sites, years when release occurred, and amount of release. We also collected data on incident cases of non-Hodgkin lymphoma (NHL) from the Georgia Comprehensive Cancer Registry (GCCR) for the years 1999-2008. We constructed distance-decay surrogate exposure metrics and Poisson and negative binomial regression models of NHL incidence to quantify associations between passive exposure to benzene and NHL risk and examined the impact of amount, duration of exposure, and lag time on cancer development. Akaike's information criteria (AIC) were used to determine the scaling factors for benzene dispersion and exposure periods that best predicted NHL risk. Using a range of scaling factors and exposure periods, we found that increased levels of passive benzene exposure were associated with higher risk of NHL. The best fitting model, with a scaling factor of 4 kilometers (km) and exposure period of 1989-1993, showed that higher exposure levels were associated with increased NHL risk (Level 4 (1.1-160kilograms (kg)) vs. Level 1: risk ratio 1.56 [1.44-1.68], Level 5 (>160kg) vs. Level 1: 1.60 [1.48-1.74]). Higher levels of passive benzene exposure are associated with increased NHL risk across various lag periods. Additional epidemiological studies are needed to refine these models and better quantify the expected total passive benzene exposure in areas surrounding release sites. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  12. A review of the data quality and comparability of case-control studies of low-level exposure to benzene in the petroleum industry.

    NARCIS (Netherlands)

    Miller, B.G.; Fransman, W.|info:eu-repo/dai/nl/314000461; Heederik, D.|info:eu-repo/dai/nl/072910542; Hurley, J.F.; Kromhout, H.|info:eu-repo/dai/nl/074385224; Fitzsimons, E.

    2010-01-01

    PURPOSE: Published case-control studies of risks of leukaemia following low exposures to benzene in the distribution of petroleum (gasoline) have not all identified the same level of risk, but the studies have had differences in cohort inclusion, case determination and availability of occupational

  13. Exposure to benzene in a pooled analysis of petroleum industry case-control studies.

    Science.gov (United States)

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

    2017-11-01

    Cases of lymphohematopoietic cancer from three petroleum industry cohorts, matched to controls from the respective cohort, were pooled into single study. Average benzene exposure was quantitatively estimated in ppm for each job based on measured data from the relevant country, adjusted for the specific time period, site and job exposure characteristics and the certainty of the exposure estimate scored. The probability of dermal exposure and of peak exposure was also assessed. Before risk was examined, an exposure estimate comparison and rationalisation exercise was performed across the studies to ensure accuracy and consistency of approach. This article evaluates the final exposure estimates and their use in the risk assessments. Overall benzene exposure estimates were low: 90% of participants accumulated less than 20 ppm-years. Mean cumulative exposure was estimated as 5.15 ppm-years, mean duration was 22 years, and mean exposure intensity was 0.2 ppm. 46% of participants were allocated a peak exposure (>3 ppm at least weekly). 40% of participants had a high probability of dermal exposure (based on the relative probability of at least weekly exposure). There were differences in mean intensity of exposure, probability of peak, and/or dermal exposure associated with job category, job site, and decade of exposure. Terminal Operators handling benzene-containing products were the most highly exposed group, followed by Tanker Drivers carrying gasoline. Exposures were higher around 1940-1950 and lower in more recent decades. Overall confidence in the exposure estimates was highest for recently held jobs and for white-collar jobs. We used sensitivity analyses, which included and excluded case-sets on the basis of exposure certainty scores, to inform the risk assessment. The above analyses demonstrated that the different patterns of exposure across the three studies are largely attributable to differences in jobs, site types, and time frames rather than study. This

  14. Personal exposure to benzene from fuel emissions among commercial fishers: comparison of two-stroke, four-stroke and diesel engines.

    Science.gov (United States)

    Kirrane, Ellen; Loomis, Dana; Egeghy, Peter; Nylander-French, Leena

    2007-03-01

    Commercial fishers are exposed to unburned hydrocarbon vapors and combustion products present in the emissions from their boat engines. The objective of this study was to measure personal exposure to benzene as a marker of fuel exposure, and to predict exposure levels across categories of carbureted two-stroke, four-stroke and diesel engines. A self-monitoring approach, employing passive monitors, was used to obtain measurements of personal exposure to benzene over time. Mixed-effect linear regression models were used to predict exposure levels, identify significant effects and determine restricted maximum likelihood estimates for within- and between-person variance components. Significant fixed effects for engine type and refueling a car or truck were identified. After controlling for refueling, predicted benzene exposure levels to fishers on boats equipped with two-stroke, four-stroke and diesel engines were 58.4, 38.9 and 15.7 microg/m3, respectively. The logged within-person variance component was 1.43, larger than the between-person variance component of 1.13, indicating that the total variation may be attributable to monitor placement, environmental conditions and other factors that change over time as well as differences between individual work practices. The health consequences of exposure to marine engine emissions are not known. The predicted levels are well below those at which health effects have been attributed, however.

  15. Personal exposure to benzene of selected population groups and impact of commuting modes in Ho Chi Minh, Vietnam.

    Science.gov (United States)

    Lan, Tran Thi Ngoc; Liem, Ngo Quang; Binh, Nguyen Thi Thanh

    2013-04-01

    Personal exposure to benzene of selected population groups, and impacts of traffic on commuters in Ho Chi Minh City were investigated. The study was carried out in June, July and November 2010. The preliminary data showed that on average, personal exposure to benzene for non-occupational people in Ho Chi Minh is ~18 μg/m(3) and most of the exposure is due to commuting. Benzene exposure during travelling by bus, taxi and motorcycle is, respectively, 22-30, 22-39 and 185-240 μg/m(3). Motorcycle-taxi drivers, petrol filling employees and street vendors suffer high daily exposures at 116, 52, 32 μg/m(3), respectively. Further measurements are needed for a better risk assessment and finding effective measures to reduce exposure. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Evaluating the effects of maternal exposure to benzene, toluene, ethyl benzene, and xylene on oral clefts among offspring in Texas: 1999-2008.

    Science.gov (United States)

    Ramakrishnan, Anushuya; Lupo, Philip J; Agopian, A J; Linder, Stephen H; Stock, Thomas H; Langlois, Peter H; Craft, Elena

    2013-08-01

    There is evidence from previous studies that maternal occupational exposure to hazardous air pollutants (HAPs) is positively associated with oral clefts; however, studies evaluating the association between residential exposure to these toxicants and oral clefts are lacking. Therefore, our goal was to conduct a case-control study examining the association between estimated maternal residential exposure to benzene, toluene, ethyl benzene, and xylene (BTEX) and the risk of oral clefts among offspring. Data on 6045 nonsyndromic isolated oral cleft cases (3915 cleft lip with or without cleft palate [CL ± P] and 2130 nonsyndromic isolated cleft palate [CP] cases) delivered between 1999 and 2008 were obtained from the Texas Birth Defects Registry. The control group was a sample of unaffected live births, frequency matched to cases on year of birth. Census tract-level estimates of annual average exposures were obtained from the U.S. Environmental Protection Agency 2005 Hazardous Air Pollutant Exposure Model (HAPEM5) for each pollutant and assigned to each subject based on maternal residence during pregnancy. Logistic regression was used to assess the relationship between estimated maternal exposure to each pollutant (BTEX) separately and the risk of oral clefts in offspring. High estimated maternal exposure to benzene was not associated with oral clefts, compared with low estimated exposure (CL ± P adjusted OR = 0.95; 95% CI = 0.81 - 1.12; CP adjusted OR = 0.85; 95% CI = 0.67 - 1.09). Similar results were seen for the other pollutants. In our study, there was no evidence that maternal exposure to environmental levels of BTEX was associated with oral clefts. Copyright © 2013 Wiley Periodicals, Inc.

  17. Biological monitoring of exposure to low concentrations of benzene in workers at a metallurgical coke production plant: new insights into S-phenylmercapturic acid and urinary benzene.

    Science.gov (United States)

    Lovreglio, Piero; De Palma, Giuseppe; Barbieri, Anna; Andreoli, Roberta; Drago, Ignazio; Greco, Luciano; Gallo, Elisabetta; Diomede, Laura; Scaramuzzo, Pietro; Ricossa, Maria Cristina; Fostinelli, Jacopo; Apostoli, Pietro; Soleo, Leonardo

    2018-02-01

    Urinary S-phenylmercapturic acid (SPMA) and benzene (U-Ben) are usually measured at the end of the work shift (ES), although their kinetic of elimination is not clearly known. To investigate SPMA and U-Ben elimination 16 h after the ES, in 93 coke production workers exposed to low benzene concentrations. Airborne benzene (A-Ben) was measured by passive samplings, while SPMA, U-Ben, methyl-tert-butyl ether (U-MTBE), cotinine (U-Cot) and creatinine were determined on urine samples collected at ES and before the beginning of the next work shift (next BS). Median A-Ben concentrations were 17.2 µg/m 3 in the personal and 34.7 µg/m 3 in the stationary samplings. SPMA was always detectable, whereas U-Ben was below the limit of quantification in 26.7% of the ES and 35.6% of the next BS samples, and U-MTBE in more than the 80.0% of the samples. At both the sampling times, SPMA and U-Ben showed a positive dependence on personal A-Ben, as well as on creatinine and U-Cot values. SPMA and U-Ben at the next BS were dependent on the exposure to low benzene concentrations suffered in the previous work shift, prompting a reconsideration of the urine sampling time recommended by the American Conference Governmental Industrial Hygienists (ACGIH).

  18. Utilization of breath analysis for exposure estimates of benzene associated with active smoking.

    Science.gov (United States)

    Jo, W K; Pack, K W

    2000-06-01

    This study included three different experiments for benzene exposures associated with active smoking. In the first experiment, the mean exhaled breath benzene concentrations measured 1 min after an active smoke ranged from 58.1 to 81.3 microgram/m(3), depending on the commercial cigarette brand, while those measured prior to an active smoke ranged from 15.9 to 19.2 microgram/m(3). The postexposure breath concentrations were much higher than the mean breath concentrations reported by some previous studies whose exposure conditions and postsampling times were not controlled. Similar to some previous decay studies conducted for different volatile organic compounds in different microenvironments, our second experiment showed that there was a rapid fall in the breath concentration and thereafter the decrease was much slower. One-compartment half-lives ranged from 30.1 to 57.8 min. Two-compartment half-lives ranged from 3.2 to 25.7 min for the first half-life and from 67 to 462 min for the second half-life. In the final repeated smoke experiment conducted with two specified time intervals, the breath concentrations showed increasing trends for both the pre- and the post exposure concentrations, with few exceptions. However, none of the changes were statistically significant at P<0.05. Copyright 2000 Academic Press.

  19. Customer exposure to MTBE, TAME, C6 alkyl methyl ethers, and benzene during gasoline refueling.

    Science.gov (United States)

    Vainiotalo, S; Peltonen, Y; Ruonakangas, A; Pfäffli, P

    1999-02-01

    We studied customer exposure during refueling by collecting air samples from customers' breathing zone. The measurements were carried out during 4 days in summer 1996 at two Finnish self-service gasoline stations with "stage I" vapor recovery systems. The 95-RON (research octane number) gasoline contained approximately 2.7% methyl tert-butyl ether (MTBE), approximately 8.5% tert-amyl methyl ether (TAME), approximately 3.2% C6 alkyl methyl ethers (C6 AMEs), and 0.75% benzene. The individual exposure concentrations showed a wide log-normal distribution, with low exposures being the most frequent. In over 90% of the samples, the concentration of MTBE was higher (range values were well below the short-term (15 min) threshold limits set for occupational exposure (250-360 mg/m3). At station A, the geometric mean concentrations in individual samples were 3.9 mg/m3 MTBE and 2. 2 mg/m3 TAME. The corresponding values at station B were 2.4 and 1.7 mg/m3, respectively. The average refueling (sampling) time was 63 sec at station A and 74 sec at station B. No statistically significant difference was observed in customer exposures between the two service stations. The overall geometric means (n = 167) for an adjusted 1-min refueling time were 3.3 mg/m3 MTBE and 1.9 mg/m3 TAME. Each day an integrated breathing zone sample was also collected, corresponding to an arithmetic mean of 20-21 refuelings. The overall arithmetic mean concentrations in the integrated samples (n = 8) were 0.90 mg/m3 for benzene and 0.56 mg/m3 for C6 AMEs calculated as a group. Mean MTBE concentrations in ambient air (a stationary point in the middle of the pump island) were 0.16 mg/m3 for station A and 0.07 mg/m3 for station B. The mean ambient concentrations of TAME, C6 AMEs, and benzene were 0.031 mg/m3, approximately 0.005 mg/m3, and approximately 0.01 mg/m3, respectively, at both stations. The mean wind speed was 1.4 m/sec and mean air temperature was 21 degreesC. Of the gasoline refueled during the

  20. Exposures to jet fuel and benzene during aircraft fuel tank repair in the U.S. Air Force.

    Science.gov (United States)

    Carlton, G N; Smith, L B

    2000-06-01

    Jet fuel and benzene vapor exposures were measured during aircraft fuel tank entry and repair at twelve U.S. Air Force bases. Breathing zone samples were collected on the fuel workers who performed the repair. In addition, instantaneous samples were taken at various points during the procedures with SUMMA canisters and subsequent analysis by mass spectrometry. The highest eight-hour time-weighted average (TWA) fuel exposure found was 1304 mg/m3; the highest 15-minute short-term exposure was 10,295 mg/m3. The results indicate workers who repair fuel tanks containing explosion suppression foam have a significantly higher exposure to jet fuel as compared to workers who repair tanks without foam (p fuel, absorbed by the foam, to volatilize during the foam removal process. Fuel tanks that allow flow-through ventilation during repair resulted in lower exposures compared to those tanks that have only one access port and, as a result, cannot be ventilated efficiently. The instantaneous sampling results confirm that benzene exposures occur during fuel tank repair; levels up to 49.1 mg/m3 were found inside the tanks during the repairs. As with jet fuel, these elevated benzene concentrations were more likely to occur in foamed tanks. The high temperatures associated with fuel tank repair, along with the requirement to wear vapor-permeable cotton coveralls for fire reasons, could result in an increase in the benzene body burden of tank entrants.

  1. A review of the data quality and comparability of case-control studies of low-level exposure to benzene in the petroleum industry.

    Science.gov (United States)

    Miller, B G; Fransman, W; Heederik, D; Hurley, J F; Kromhout, H; Fitzsimons, E

    2010-01-01

    Published case-control studies of risks of leukaemia following low exposures to benzene in the distribution of petroleum (gasoline) have not all identified the same level of risk, but the studies have had differences in cohort inclusion, case determination and availability of occupational and lifestyle data. We reviewed the quality and comparability of the data from three (of four) studies. Through site visits, discussions with the investigators and reading study reports, we reviewed and audited the methods used for selecting cases and controls, for estimating individual exposures and for analysing and interpreting the data. Case-control comparisons of exposures were examined using customized graphs. We found that there were no issues of subject selection, methods or general data quality that were likely to have distorted their internal comparisons; we could not check in detail whether the metric for exposure assessments was the same across the studies; the exposure assessments for the Australian study required the least backward estimation, and the Canadian, which also had fewest cases, the most; evidence of an increased risk at higher exposures in Australia was convincing. The findings are consistent with some effect of benzene at higher lifetime exposures. A proposed pooled analysis should improve quantification of any exposure-response relationship.

  2. Toxicogenomic analysis of gene expression changes in rat liver after a 28-day oral benzene exposure

    NARCIS (Netherlands)

    Heijne, W.H.M.; Jonker, D.; Stierum, R.H.; Ommen, B. van; Groten, J.P.

    2005-01-01

    Benzene is an industrial chemical, component of automobile exhaust and cigarette smoke. After hepatic bioactivation benzene induces bone marrow, blood and hepatic toxicity. Using a toxicogenomics approach this study analysed the effects of benzene at three dose levels on gene expression in the liver

  3. Exposure to benzene induces oxidative stress, alters the immune response and expression of p53 in gasoline filling workers.

    Science.gov (United States)

    Uzma, Nazia; Kumar, B Santhosh; Hazari, Mohammed Abdul Hannan

    2010-12-01

    Chronic exposure to benzene can lead to deleterious effects on many biological systems including blood and blood-forming organs. We investigated the adverse effects of benzene among workers occupationally exposed to benzene in India. Four hundred twenty-eight gasoline filling workers occupationally exposed to benzene and 78 unexposed individuals were recruited for this study. Benzene concentration was determined by gas chromatography, reactive oxygen species (ROS) by dichlorofluorescin diacetate (DCFH-DA) method, malondialdehyde (MDA) by thiobarbituric acid reactive substances assay (TBARS), total superoxide dismutase (T-SOD) by RANSOD kit and glutathione (GSH) by 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB) reaction, respectively. CD4, CD8, IgG were carried out by using fluorescence activated cell sorter (FACS Calibur) and mRNA expression of p53 by reverse transcriptase PCR (RT-PCR). A significant increase in the concentration of benzene and its byproducts in both blood and urine were found in the workers compared with the controls. The levels of ROS and MDA were significantly elevated, and GSH and total T-SOD were decreased in the workers compared with the controls. A statistically significant decrease in the immunoglobulin levels, CD4T cells, CD4/CD8 ratio was observed in workers (vs. controls), whereas no significant difference was observed in CD8T cells. p53 gene expression was markedly higher in workers than in controls. Occupational exposure to benzene causes oxidative stress, immune suppression and increases the expression of tumor-suppressing gene p53 in gasoline filling workers. These bio-functional markers might be useful in screening and surveillance for occupational hazard.

  4. Evaluation of neuropsychological symptoms and exposure to benzene, toluene and xylene among two different furniture worker groups in Izmir.

    Science.gov (United States)

    Mandiracioglu, Aliye; Akgur, Serap; Kocabiyik, Nesrin; Sener, Ufuk

    2011-10-01

    This study was conducted to determine whether there was any exposure to toluene, xylene and benzene and to assess the health impact of these solvents on workers in furniture enterprises in Karabaglar, Izmir. This cross-sectional study covered furniture enterprises in Karabaglar, Izmir. This study was comprised of an exposed group consisting of workers engaged in painting and varnishing and therefore exposed either directly or indirectly toluene, xylene and benzene in the workplace and the non-exposed group engaged in other aspects of production. While a total of 261 individuals completed questionnaires, 210 workers agreed to provide blood samples. Blood solvents levels were determined using gas chromatograph at Ege University, Intoxication Research and Application Centre. The modified EUROQUEST questionnaire was used to assess neuropsychological symptoms and neurological and general examination were performed. Occupational and exposure history, demographic and work-related information was collected. In this study of workers, blood toluene and benzene levels were found to be significantly higher among those engaged in painting and varnishing compared to those who perform other tasks. The average blood toluene and benzene concentrations among exposed workers were 6.95 times and 1.64 times respectively higher than those in the nonexposed groups. Smokers and participants who worked in excess of 8 hours/day had higher blood toluene and benzene levels. The most frequently work-related health complaints were back pain, allergies and asthma. No differences were found in the average scores in the neuropsychological symptoms questionnaire between exposed and non-exposed groups. Neurological examination of two individuals with these complaints revealed a loss of reflexes. The workers were unaware that they were being exposed to solvents at work. Tobacco smoke is a major source of internal exposure to benzene. Improving working conditions in furniture work places is a priority.

  5. Health risk characterization for exposure to benzene in service stations and petroleum refineries environments using human adverse response data.

    Science.gov (United States)

    Edokpolo, Benjamin; Yu, Qiming Jimmy; Connell, Des

    2015-01-01

    Health risk characterization of exposure to benzene in service stations and petroleum refineries has been carried out in previous studies using guideline values set by various agencies. In this work, health risk was characterized with the exposure data as cumulative probability distribution (CPD) plots but using human epidemiological data. This was achieved by using lowest observable adverse effects levels (LOAEL) data plotted as cumulative probability lowest effects distribution (CPLED). The health risk due to benzene was characterized by using probabilistic methods of hazard quotient (HQ 50/50 and HQ 95/5 ), Monte-Carlo simulation (MCS) and overall risk probability (ORP). CPD relationships of adverse health effects relationships and exposure data were in terms of average daily dose (ADD) and lifetime average daily dose (LADD) for benzene. For service station environments HQ 50/50 and HQ 95/5 were in a range of 0.000071-0.055 and 0.0049-21, respectively. On the other hand, the risk estimated for petroleum refinery environments suggests higher risk with HQ 50/50 and HQ 95/5 values ranging from 0.0012 to 77 and 0.17 to 560, respectively. The results of Monte-Carlo risk probability (MRP) and ORP indicated that workers in petroleum refineries (MRP of 2.9-56% and ORP of 4.6-52% of the affected population) were at a higher risk of adverse health effects from exposure to benzene as compared to exposure to benzene in service station environments (MRP of 0.051 -3.4% and ORP of 0.35-2.7% affected population). The adverse effect risk probabilities estimated by using the Monte-Carlo simulation technique and the ORP method were found to be generally consistent.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-12-01

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

  7. Ensuring comparability of benzene exposure estimates across three nested case-control studies in the petroleum industry in support of a pooled epidemiological analysis.

    Science.gov (United States)

    Glass, D C; Armstrong, T W; Pearlman, E D; Verma, D K; Schnatter, A R; Rushton, L

    2010-03-19

    least two studies in two eras. If the AM of the WE group differed by more than 20%, the data were examined to see whether the difference was justified by differences in local exposure conditions, such as an enclosure versus open work area. Estimates were adjusted in the absence of justification for the difference. Reconciliation of differences resulted in changes to a small number of underlying BEs, particularly the background values, also the BEs attributed to some individuals and changes to the allocation of jobs between Job Categories. Although the studies covered some differing sectors of the industry and different time periods, for 22 Job Categories there was sufficient overlap, particularly in the downstream distribution sector, to make comparisons possible. After adjustment 12 Job Categories were judged to be similar and 10 were judged to be justifiably different. Job-based peak and skin exposure estimates were applied in a uniform way across the studies and a single approach to scoring the certainty of the exposure estimates was identified. The revised exposure estimates will be used in the pooled analysis to examine the risk of haematopoietic cancers and benzene exposure. This exercise provided an important quality control check on the exposure estimates and identified similarly exposed Job Categories that could be grouped for risk assessment analyses. Copyright (c) 2009 Elsevier Ireland Ltd. All rights reserved.

  8. Altered Expression of Genes in Signaling Pathways Regulating Proliferation of Hematopoietic Stem and Progenitor Cells in Mice with Subchronic Benzene Exposure.

    Science.gov (United States)

    Sun, Rongli; Zhang, Juan; Xiong, Mengzhen; Wei, Haiyan; Tan, Kehong; Yin, Lihong; Pu, Yuepu

    2015-08-07

    Leukemias and hematopoietic disorders induced by benzene may arise from the toxicity of benzene to hematopoietic stem or progenitor cells (HS/PCs). Since there is a latency period between initial benzene exposure and the development of leukemia, subsequent impact of benzene on HS/PCs are crucial for a deeper understanding of the carcinogenicity and hematotoxicity in post-exposure stage. This study aims to explore the effects of benzene on HS/PCs and gene-expression in Wnt, Notch and Hh signaling pathways in post-exposure stage. The C3H/He mice were injected subcutaneously with benzene (0, 150, 300 mg/kg/day) for three months and were monitored for another 10 months post-exposure. The body weights were monitored, the relative organ weights, blood parameters and bone marrow smears were examined. Frequency of lineage(-) sca-1(+) c-kit(+) (LSK) cells, capability of colony forming and expression of genes in Wnt, Notch and Hedghog (Hh) signaling pathways were also analyzed. The colony formation of the progenitor cells for BFU-E, CFU-GEMM and CFU-GM was significantly decreased with increasing benzene exposure relative to controls, while no significant difference was observed in colonies for CFU-G and CFU-M. The mRNA level of cyclin D1 was increased and Notch 1 and p53 were decreased in LSK cells in mice exposed to benzene but with no statistical significance. These results suggest that subsequent toxic effects of benzene on LSK cells and gene expression in Wnt, Notch and Hh signaling pathways persist in post-exposure stage and may play roles in benzene-induced hematotoxicity.

  9. Occupational Exposure to Benzene and Non-Hodgkin Lymphoma in a Population-Based Cohort: The Shanghai Women’s Health Study

    Science.gov (United States)

    Friesen, Melissa C.; Vermeulen, Roel; Shu, Xiao-Ou; Purdue, Mark P.; Stewart, Patricia A.; Xiang, Yong-Bing; Chow, Wong-Ho; Zheng, Tongzhang; Ji, Bu-Tian; Yang, Gong; Linet, Martha S.; Hu, Wei; Zhang, Heping; Zheng, Wei; Gao, Yu-Tang; Rothman, Nathaniel; Lan, Qing

    2015-01-01

    Background The association between benzene exposure and non-Hodgkin lymphoma (NHL) has been the subject of debate as a result of inconsistent epidemiologic evidence. An International Agency for Research on Cancer (IARC) working group evaluated benzene in 2009 and noted evidence for a positive association between benzene exposure and NHL risk. Objective We evaluated the association between occupational benzene exposure and NHL among 73,087 women enrolled in the prospective population-based Shanghai Women’s Health Study. Methods Benzene exposure estimates were derived using a previously developed exposure assessment framework that combined ordinal job-exposure matrix intensity ratings with quantitative benzene exposure measurements from an inspection database of Shanghai factories collected between 1954 and 2000. Associations between benzene exposure metrics and NHL (n = 102 cases) were assessed using Cox proportional hazard models, with study follow-up occurring from December 1996 through December 2009. Results Women ever exposed to benzene had a significantly higher risk of NHL [hazard ratio (HR) = 1.87, 95% CI: 1.19, 2.96]. Compared with unexposed women, significant trends in NHL risk were observed for increasing years of benzene exposure (ptrend = 0.006) and increasing cumulative exposure levels (ptrend = 0.005), with the highest duration and cumulative exposure tertiles having a significantly higher association with NHL (HR = 2.07, 95% CI: 1.07, 4.01 and HR = 2.16, 95% CI: 1.17, 3.98, respectively). Conclusions Our findings, using a population-based prospective cohort of women with diverse occupational histories, provide additional evidence that occupational exposure to benzene is associated with NHL risk. Citation Bassig BA, Friesen MC, Vermeulen R, Shu XO, Purdue MP, Stewart PA, Xiang YB, Chow WH, Zheng T, Ji BT, Yang G, Linet MS, Hu W, Zhang H, Zheng W, Gao YT, Rothman N, Lan Q. 2015. Occupational exposure to benzene and non-Hodgkin lymphoma in a population

  10. A simultaneous job- and task-based exposure evaluation of petroleum tanker drivers to benzene and total hydrocarbons.

    Science.gov (United States)

    Verma, Dave K; Cheng, Wai K; Shaw, Don S; Shaw, M Lorraine; Verma, Paul; Julian, Jim A; Dumschat, Reinhard E; Mulligan, Sharon J P

    2004-11-01

    A simultaneous job- and task-based exposure study was conducted for tanker drivers delivering petroleum products from several bulk terminals and an agency to retail outlets. Full-shift (job-based) samples and job component tasks samples were collected simultaneously. The tasks sampled included loading, unloading, and travel. Three hundred sixty-six personal charcoal tube samples were collected. Full-shift visual observations of work practices and real-time monitoring using a data logging hydrocarbon analyzer were also conducted. Multiple measurements per worker were made, which permitted an assessment of sampling variability within and between workers. The highest exposures for drivers occurred during unloading at the agency. The mean benzene exposure for agency drivers was 0.88 ppm for full-shift time-weighted average, 2.86 ppm for unloading, and 0.54 ppm for loading. For bulk terminal drivers, the mean benzene level without vapor control was 0.12 ppm for time weighted average, 0.24 ppm for unloading, and 0.33 ppm for loading. The time-weighted average exposure of the agency and bulk terminal drivers based on the data collected and the lognormal model can be expected to exceed threshold limit value-time weighted average of 0.5 ppm for benzene about 70 and 2% of the time, respectively. Agency drivers' unloading and loading tasks accounted for approximately 30% and 7% of the total time, and 95% and 4% of total exposure, respectively. For the bulk terminal drivers, mean unloading and loading tasks constituted 24% and 12% of the total time, and 68% and 19% of the total exposure, respectively. Travel activity accounted for an average of 63% of the total time for agency and 64% for bulk terminal drivers, but only contributed agencies. Vapor control technology at the terminal effectively reduces exposure (by almost 50%) and fugitive emissions.

  11. Benzene Exposure Alters Expression of Enzymes Involved in Fatty Acid β-Oxidation in Male C3H/He Mice

    Directory of Open Access Journals (Sweden)

    Rongli Sun

    2016-10-01

    Full Text Available Benzene is a well-known hematotoxic carcinogen that can cause leukemia and a variety of blood disorders. Our previous study indicated that benzene disturbs levels of metabolites in the fatty acid β-oxidation (FAO pathway, which is crucial for the maintenance and function of hematopoietic and leukemic cells. The present research aims to investigate the effects of benzene on changes in the expression of key enzymes in the FAO pathway in male C3H/He mice. Results showed that benzene exposure caused reduced peripheral white blood cell (WBC, red blood cell (RBC, platelet (Pit counts, and hemoglobin (Hgb concentration. Investigation of the effects of benzene on the expression of FA transport- and β-oxidation-related enzymes showed that expression of proteins Cpt1a, Crat, Acaa2, Aldh1l2, Acadvl, Crot, Echs1, and Hadha was significantly increased. The ATP levels and mitochondrial membrane potential decreased in mice exposed to benzene. Meanwhile, reactive oxygen species (ROS, hydrogen peroxide (H2O2, and malondialdehyde (MDA levels were significantly increased in the benzene group. Our results indicate that benzene induces increased expression of FA transport and β-oxidation enzymes, mitochondrial dysfunction, and oxidative stress, which may play a role in benzene-induced hematotoxicity.

  12. Leukemia mortality by cell type in petroleum workers with potential exposure to benzene.

    OpenAIRE

    Raabe, G K; Wong, O

    1996-01-01

    Workers in the petroleum industry are potentially exposed to a variety of petrochemicals, including benzene or benzene-containing liquids. Although a large number of studies of petroleum workers have been conducted to examine leukemia and other cancer risks, few existing studies have investigated cell-type-specific leukemias. One of the major reasons for the lack of cell-type-specific analysis was the small number of deaths by cell type in individual studies. In the present investigation, all...

  13. Socioeconomic status and exposure to outdoor NO2 and benzene in the Asturias INMA birth cohort, Spain.

    Science.gov (United States)

    Fernández-Somoano, Ana; Tardon, Adonina

    2014-01-01

    It is commonly assumed that low socioeconomic levels are associated with greater exposure to pollution, but this is not necessarily valid. Our goal was to examine how individual socioeconomic characteristics are associated with exposure levels in a Spanish region included in the INfancia y Medio Ambiente (INMA) cohort. The study population comprised 430 pregnant women from the Asturias INMA cohort. Air pollution exposure was estimated using land-use regression techniques. Information about the participants' lifestyle and socioeconomic variables was collected through questionnaires. In multivariate analysis, the levels of NO2 and benzene assigned to each woman were considered as dependent variables. Other variables included in the models were residential zone, age, education, parity, smoking, season, working status during pregnancy and social class. The average NO2 level was 23.60 (SD=6.50) μg/m(3). For benzene, the mean value was 2.31 (SD=1.32) μg/m(3). We found no association of any pollutant with education. We observed an association between social class and benzene levels. Social classes I and II had the highest levels. The analysed socioeconomic and lifestyle variables accounted for little variability in air pollution in the models; this variability was explained mainly by residential zone (adjusted R(2): 0.27 for NO2; 0.09 for benzene). Education and social class were not clearly associated with pollution. Administrations should monitor the environment of residential areas regardless of the socioeconomic level, and they should increase the distances between housing and polluting sources to prevent settlements at distances that are harmful to health.

  14. Optimization of SPE for Analysis of Mandelic Acid as a Biomarker of Exposure to Ethyl Benzene

    Directory of Open Access Journals (Sweden)

    SJ Shahtaheri, M Abdollahi, F Golbabaei, A Rahimi-Froushani, F Ghamari

    2004-10-01

    Full Text Available Ethyl benzene is an important constituent of widely used solvents in industries and laboratories, causing widespread environmental and industrial pollutions. For evaluation of occupational exposure to such pollutants, biological monitoring is an essential process, in which, preparation of environmental and biological samples is one of the most time-consuming and error-prone aspects prior to chromatographic techniques. The use of solid-phase extraction (SPE has been grown and is a fertile technique of sample preparation as it provides better results than those of liquid-liquid extraction (LLE. In this study, SPE using bonded silica has been optimized with regard to sample pH, sample concentration, elution solvent, elution volume, sorbent type, and sorbent mass. Through experimental evaluation, a strong anion exchange silica cartridge (SAX has been found successful in simplifying sample preparation. The present approach proved that, mandelic acid could be retained on SAX sorbent based on specific interaction. Further study was employed using 10% acetic acid to extract the analyte from spiked urine and gave a clean sample for HPLC-UV system. In this study, a high performance liquid chromatography, using reverse-phase column was used. The isocratic run was done at a constant flow rate of 0.85 ml/min, the mobile phase was water/methanol/acetic acid and a UV detector was used, setting at 225 nm. At the developed conditions the extraction recovery was exceeded 98%. The factors were evaluated statically and also validated with three different pools of spiked urine samples and showed a good reproducibility over six consecutive days as well as six within-day experiments.

  15. Comparison of the near field/far field model and the advanced reach tool (ART) model V1.5: exposure estimates to benzene during parts washing with mineral spirits.

    Science.gov (United States)

    LeBlanc, Mallory; Allen, Joseph G; Herrick, Robert F; Stewart, James H

    2018-03-01

    The Advanced Reach Tool V1.5 (ART) is a mathematical model for occupational exposures conceptually based on, but implemented differently than, the "classic" Near Field/Far Field (NF/FF) exposure model. The NF/FF model conceptualizes two distinct exposure "zones"; the near field, within approximately 1m of the breathing zone, and the far field, consisting of the rest of the room in which the exposure occurs. ART has been reported to provide "realistic and reasonable worst case" estimates of the exposure distribution. In this study, benzene exposure during the use of a metal parts washer was modeled using ART V1.5, and compared to actual measured workers samples and to NF/FF model results from three previous studies. Next, the exposure concentrations expected to be exceeded 25%, 10% and 5% of the time for the exposure scenario were calculated using ART. Lastly, ART exposure estimates were compared with and without Bayesian adjustment. The modeled parts washing benzene exposure scenario included distinct tasks, e.g. spraying, brushing, rinsing and soaking/drying. Because ART can directly incorporate specific types of tasks that are part of the exposure scenario, the present analysis identified each task's determinants of exposure and performance time, thus extending the work of the previous three studies where the process of parts washing was modeled as one event. The ART 50th percentile exposure estimate for benzene (0.425ppm) more closely approximated the reported measured mean value of 0.50ppm than the NF/FF model estimates of 0.33ppm, 0.070ppm or 0.2ppm obtained from other modeling studies of this exposure scenario. The ART model with the Bayesian analysis provided the closest estimate to the measured value (0.50ppm). ART (with Bayesian adjustment) was then used to assess the 75th, the 90th and 95th percentile exposures, predicting that on randomly selected days during this parts washing exposure scenario, 25% of the benzene exposures would be above 0.70ppm; 10

  16. Characterisation of urban inhalation exposures to benzene, formaldehyde and acetaldehyde in the European Union: comparison of measured and modelled exposure data.

    Science.gov (United States)

    Bruinen de Bruin, Yuri; Koistinen, Kimmo; Kephalopoulos, Stylianos; Geiss, Otmar; Tirendi, Salvatore; Kotzias, Dimitrios

    2008-07-01

    All across Europe, people live and work in indoor environments. On average, people spend around 90% of their time indoors (homes, workplaces, cars and public transport means, etc.) and are exposed to a complex mixture of pollutants at concentration levels that are often several times higher than outdoors. These pollutants are emitted by different sources indoors and outdoors and include volatile organic compounds (VOCs), carbonyls (aldehydes and ketones) and other chemical substances often adsorbed on particles. Moreover, legal obligations opposed by legislations, such as the European Union's General Product Safety Directive (GPSD) and Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH), increasingly require detailed understanding of where and how chemical substances are used throughout their life-cycle and require better characterisation of their emissions and exposure. This information is essential to be able to control emissions from sources aiming at a reduction of adverse health effects. Scientifically sound human risk assessment procedures based on qualitative and quantitative human exposure information allows a better characterisation of population exposures to chemical substances. In this context, the current paper compares inhalation exposures to three health-based EU priority substances, i.e. benzene, formaldehyde and acetaldehyde. Distributions of urban population inhalation exposures, indoor and outdoor concentrations were created on the basis of measured AIRMEX data in 12 European cities and compared to results from existing European population exposure studies published within the scientific literature. By pooling all EU city personal exposure, indoor and outdoor concentration means, representative EU city cumulative frequency distributions were created. Population exposures were modelled with a microenvironment model using the time spent and concentrations in four microenvironments, i.e. indoors at home and at work, outdoors

  17. Benzene and its Health Effects

    Directory of Open Access Journals (Sweden)

    Mustafa Tozun

    2008-12-01

    Full Text Available Benzene is an aromatic hydrocarbon, colorless, sweet-smelling liquid. It is an important industrial solvent, is used in the manufacture of plastics, detergents, pesticides, and other chemicals. Benzene is a carcinogen. Short-term and high level benzene exposure causes symptoms of the central nervous system. Long-term benzene exposure may affect to bone marrow and blood production. Additionally, genotoxic, immunological, and urogenital negative effects may occur with chronicle benzene exposure. [TAF Prev Med Bull 2008; 7(6.000: 541-546

  18. Promoter methylation status in genes related with inflammation, nitrosative stress and xenobiotic metabolism in low-level benzene exposure: Searching for biomarkers of oncogenesis.

    Science.gov (United States)

    Jiménez-Garza, Octavio; Guo, Liqiong; Byun, Hyang-Min; Carrieri, Mariella; Bartolucci, Giovanni Battista; Zhong, Jia; Baccarelli, Andrea A

    2017-11-01

    Exposure to low levels of benzene may cause acute myeloid leukemia in humans. Epigenetic effects in benzene exposure have been studied for tumor suppressor genes and oxidative stress-related genes, but other cellular pathways must be explored. Here, we studied promoter DNA methylation of IL6, CYP2E1 and iNOS in blood cells from three groups of workers: a) gas station attendants (GS) exposed to low levels of benzene; b) plastic shoe factory workers (PS) exposed to other solvents different to benzene and c) administrative workers as a reference group with no solvent exposure (C). IL6 promoter methylation was higher in GS workers (p benzene levels (r = -0.47, p benzene. Correlations between iNOS methylation with both CYP2E1 methylation and urinary SPMA levels represent novel evidence about CYP2E1 epigenetic regulation and activity related with nitrosative stress, making promoter methylation status of these genes a potential biomarker in early stages of oncogenesis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Validation of Armadillo officinalis Dumèril, 1816 (Crustacea, Isopoda, Oniscidea) as a bioindicator: in vivo study of air benzene exposure.

    Science.gov (United States)

    Agodi, A; Oliveri Conti, G; Barchitta, M; Quattrocchi, A; Lombardo, B M; Montesanto, G; Messina, G; Fiore, M; Ferrante, M

    2015-04-01

    This study tests the potential for using Armadillo officinalis as a bioindicator of exposure to and activation of benzene metabolic pathways using an in vivo model. A. officinalis specimens collected in a natural reserve were divided into a control and three test groups exposed to 2.00, 5.32 or 9.09 µg/m(3) benzene for 24h. Three independent tests were performed to assess model reproducibility. Animals were dissected to obtain three pooled tissue samples per group: hepatopancreas (HEP), other organs and tissues (OOT), and exoskeleton (EXO). Muconic acid (MA), S-phenylmercapturic acid (S-PMA), two human metabolites of benzene, and changes in mtDNA copy number, a human biomarker of benzene exposure, were determined in each sample; benzene was determined only in EXO. MA was measured by high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection, S-PMA by triple quadrupole mass spectrometer liquid chromatography with electro spray ionization (LC-MS-ESI-TQD), mtDNA by real-time quantitative PCR and end-point PCR, and benzene by quadrupole mass spectrometer head-space gas chromatography (HSGC-MS). MA and S-PMA levels rose both in HEP and OOT; EXO exhibited increasing benzene concentrations; and mtDNA copy number rose in HEP but not in OOT samples. Overall, our findings demonstrate that A. officinalis is a sensitive bioindicator of air benzene exposure and show for the first time its ability to reproduce human metabolic dynamics. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Benzene and superior counterpart; Benzene et homologues superieurs

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-07-01

    A century ago, the first case of purpura and acute anemia provoked by benzene was described. Afterwards, others important toxic effects in relation with the exposure to this solvent were known: medullar aplasia, acute leukemia,carcinogenesis. The chronic intoxication by benzene is called benzenism, the term of benzolism is devoted to the intoxication provoked by the mixture of benzene and superior counterparts: toluene, xylenes. (N.C.)

  1. Subclinical effects of groundwater contaminants. Pt. 4. Effects of repeated oral exposure to combinations of benzene and toluene on regional brain monoamine metabolism in mice

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, G.C.; Parker, R.D.R. (Utah State Univ., Logan, UT (USA). Dept. of Biology); Sharma, R.P. (Utah State Univ., Logan, UT (USA). Dept. of Animal, Dairy and Veterinary Sciences)

    1990-11-01

    The effect of combined treatment with benzene and toluene on the endogenous concentrations of the catecholamines norepinephrine (NE) and dopamine (DA), the catecholamine metabolites vanillylmandelic acid (VMA), 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), and the indoleamine serotonin (5-HT) and its metabolite 5-hydroxyindoleacetic acid (5-HIAA), were investigated in six discrete brain regions of CD-1 mice. Groups of male, adult mice were continuously exposed to benzene (166 mg/l), toluene (80 and 325 mg/l), and combinations of benzene + toluene (80 or 325 mg/l) in drinking water for 4 weeks. Benzene produced increases of NE in the hypothalamus, cortex, midbrain and medulla oblongata, DA in the hypothalamus and corpus striatum, and 5-HT in all dissected brain regions except cerebellum. Elevated levels of various monoamine metabolites were also observed in these brain areas. Toluene ingestion alone also significantly increased the concentrations of NE, DA, 5-HT, and their metabolites in several brain regions. Mice given the combined treatments exhibited raised regional neurochemical levels when compared to the untreated controls. Increased concentrations of biogenic amine metabolites in several brain regions were greater in the combined exposures of benzene and toluene than when either chemical was used alone. The findings were different from those observed on immune parameters using similar treatment protocols, where simultaneous exposure to toluene prevented the immunotoxic effects of benzene. (orig./MG).

  2. Bayesian Algorithm Implementation in a Real Time Exposure Assessment Model on Benzene with Calculation of Associated Cancer Risks

    Directory of Open Access Journals (Sweden)

    Pavlos A. Kassomenos

    2009-02-01

    Full Text Available The objective of the current study was the development of a reliable modeling platform to calculate in real time the personal exposure and the associated health risk for filling station employees evaluating current environmental parameters (traffic, meteorological and amount of fuel traded determined by the appropriate sensor network. A set of Artificial Neural Networks (ANNs was developed to predict benzene exposure pattern for the filling station employees. Furthermore, a Physiology Based Pharmaco-Kinetic (PBPK risk assessment model was developed in order to calculate the lifetime probability distribution of leukemia to the employees, fed by data obtained by the ANN model. Bayesian algorithm was involved in crucial points of both model sub compartments. The application was evaluated in two filling stations (one urban and one rural. Among several algorithms available for the development of the ANN exposure model, Bayesian regularization provided the best results and seemed to be a promising technique for prediction of the exposure pattern of that occupational population group. On assessing the estimated leukemia risk under the scope of providing a distribution curve based on the exposure levels and the different susceptibility of the population, the Bayesian algorithm was a prerequisite of the Monte Carlo approach, which is integrated in the PBPK-based risk model. In conclusion, the modeling system described herein is capable of exploiting the information collected by the environmental sensors in order to estimate in real time the personal exposure and the resulting health risk for employees of gasoline filling stations.

  3. Gene expression profile in bone marrow and hematopoietic stem cells in mice exposed to inhaled benzene

    International Nuclear Information System (INIS)

    Faiola, Brenda; Fuller, Elizabeth S.; Wong, Victoria A.; Recio, Leslie

    2004-01-01

    Acute myeloid leukemia and chronic lymphocytic leukemia are associated with benzene exposure. In mice, benzene induces chromosomal breaks as a primary mode of genotoxicity in the bone marrow (BM). Benzene-induced DNA lesions can lead to changes in hematopoietic stem cells (HSC) that give rise to leukemic clones. To gain insight into the mechanism of benzene-induced leukemia, we investigated the DNA damage repair and response pathways in total bone marrow and bone marrow fractions enriched for HSC from male 129/SvJ mice exposed to benzene by inhalation. Mice exposed to 100 ppm benzene for 6 h per day, 5 days per week for 2 week showed significant hematotoxicity and genotoxicity compared to air-exposed control mice. Benzene exposure did not alter the level of apoptosis in BM or the percentage of HSC in BM. RNA isolated from total BM cells and the enriched HSC fractions from benzene-exposed and air-exposed mice was used for microarray analysis and quantitative real-time RT-PCR. Interestingly, mRNA levels of DNA repair genes representing distinct repair pathways were largely unaffected by benzene exposure, whereas altered mRNA expression of various apoptosis, cell cycle, and growth control genes was observed in samples from benzene-exposed mice. Differences in gene expression profiles were observed between total BM and HSC. Notably, p21 mRNA was highly induced in BM but was not altered in HSC following benzene exposure. The gene expression pattern suggests that HSC isolated immediately following a 2 weeks exposure to 100 ppm benzene were not actively proliferating. Understanding the toxicogenomic profile of the specific target cell population involved in the development of benzene-associated diseases may lead to a better understanding of the mechanism of benzene-induced leukemia and may identify important interindividual and tissue susceptibility factors

  4. A review of the data quality and comparability of case-control studies of low-level exposure to benzene in the petroleum industry

    NARCIS (Netherlands)

    Miller, B.G.; Fransman, W.; Heederik, D.; Hurley, J.F.; Kromhout, H.; Fitzsimons, E.

    2010-01-01

    Purpose Published case–control studies of risks of leukaemia following low exposures to benzene in the distribution of petroleum (gasoline) have not all identiWed the same level of risk, but the studies have had diVerences in cohort inclusion, case determination and availability of occupational and

  5. Benzene patterns in different urban environments and a prediction model for benzene rates based on NOx values

    Science.gov (United States)

    Paz, Shlomit; Goldstein, Pavel; Kordova-Biezuner, Levana; Adler, Lea

    2017-04-01

    Exposure to benzene has been associated with multiple severe impacts on health. This notwithstanding, at most monitoring stations, benzene is not monitored on a regular basis. The aims of the study were to compare benzene rates in different urban environments (region with heavy traffic and industrial region), to analyse the relationship between benzene and meteorological parameters in a Mediterranean climate type, to estimate the linkages between benzene and NOx and to suggest a prediction model for benzene rates based on NOx levels in order contribute to a better estimation of benzene. Data were used from two different monitoring stations, located on the eastern Mediterranean coast: 1) a traffic monitoring station in Tel Aviv, Israel (TLV) located in an urban region with heavy traffic; 2) a general air quality monitoring station in Haifa Bay (HIB), located in Israel's main industrial region. At each station, hourly, daily, monthly, seasonal, and annual data of benzene, NOx, mean temperature, relative humidity, inversion level, and temperature gradient were analysed over three years: 2008, 2009, and 2010. A prediction model for benzene rates based on NOx levels (which are monitored regularly) was developed to contribute to a better estimation of benzene. The severity of benzene pollution was found to be considerably higher at the traffic monitoring station (TLV) than at the general air quality station (HIB), despite the location of the latter in an industrial area. Hourly, daily, monthly, seasonal, and annual patterns have been shown to coincide with anthropogenic activities (traffic), the day of the week, and atmospheric conditions. A strong correlation between NOx and benzene allowed the development of a prediction model for benzene rates, based on NOx, the day of the week, and the month. The model succeeded in predicting the benzene values throughout the year (except for September). The severity of benzene pollution was found to be considerably higher at the

  6. Biomass fuels and coke plants are important sources of human exposure to polycyclic aromatic hydrocarbons, benzene and toluene.

    Science.gov (United States)

    Fan, Ruifang; Li, Junnan; Chen, Laiguo; Xu, Zhencheng; He, Dechun; Zhou, Yuanxiu; Zhu, Yuanyuan; Wei, Fusheng; Li, Jihua

    2014-11-01

    Large amounts of carcinogenic polycyclic aromatic hydrocarbons (PAHs), benzene and toluene (BT) might be emitted from incomplete combustion reactions in both coal tar factories and biomass fuels in rural China. The health effects arising from exposure to PAHs and BT are a concern for residents of rural areas close to coal tar plants. To assess the environmental risk and major exposure sources, 100 coke plant workers and 25 farmers in Qujing, China were recruited. The levels of 10 mono-hydroxylated PAHs (OH-PAHs), four BT metabolites and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in the urine collected from the subjects were measured. The 8-OHdG levels in the urine were determined to evaluate the oxidative DNA damage induced by the PAHs and BT. The results showed that the levels of the OH-PAHs, particularly those of 1-hydroxynathalene and 1-hydroxypyrene, in the farmers were 1-7 times higher than those in the workers. The concentrations of the BT metabolites were comparable between the workers and farmers. Although the exact work location within a coke oven plant might affect the levels of the OH-PAHs, one-way ANOVA revealed no significant differences for either the OH-PAHs levels or the BT concentrations among the three groups working at different work sites. The geometric mean concentration (9.17 µg/g creatinine) of 8-OHdG was significantly higher in the farmers than in the plant workers (6.27 µg/g creatinine). The levels of 8-OHdG did not correlate with the total concentrations of OH-PAHs and the total levels of BT metabolites. Incompletely combusted biomass fuels might be the major exposure source, contributing more PAHs and BT to the local residents of Qujing. The estimated daily intakes (EDIs) of naphthalene and fluorene for all of the workers and most of the farmers were below the reference doses (RfDs) recommended by the U.S. Environmental Protection Agency (EPA), except for the pyrene levels in two farmers. However, the EDIs of benzene in the workers and local

  7. Low-dose occupational exposure to benzene and signal transduction pathways involved in the regulation of cellular response to oxidative stress.

    Science.gov (United States)

    Fenga, Concettina; Gangemi, Silvia; Giambò, Federica; Tsitsimpikou, Christina; Golokhvast, Kirill; Tsatsakis, Aristidis; Costa, Chiara

    2016-02-15

    Benzene metabolism seems to modulate NF-κB, p38-MAPK (mitogen-activated protein kinase) and signal transducer and activator of transcription 3 (STAT3) signalling pathways via the production of reactive oxygen species. This study aims to evaluate the effects of low-dose, long-term exposure on NF-κB, STAT3, p38-MAPK and stress-activated protein kinase/Jun amino-terminal kinase (SAPK/JNK) signal transduction pathways in peripheral blood mononuclear cells in gasoline station attendants. The influence of consumption of vegetables and fruits on these pathways has also been evaluated. A total of 91 men, employed in gasoline stations located in eastern Sicily, were enrolled for this study and compared with a control group of 63 male office workers with no history of exposure to benzene. The exposure was assessed by measuring urinary trans,trans-muconic acid (t,t-MA) concentration. Quantitative analyses were performed for proteins NF-κB p65, phospho-NF-κB p65, phospho-IκB-α, phospho-SAPK/JNK, phospho-p38 MAPK and phospho-STAT3 using an immunoenzymatic assay. The results of this study indicate significantly higher t,t-MA levels in gasoline station attendants. With regard to NF-κB, phospho-IκB-α and phospho-STAT3 proteins, statistically significant differences were observed in workers exposed to benzene. However, no differences were observed in SAPK/JNK and p38-MAPK activation. These changes were positively correlated with t,t-MA levels, but only phospho-NF-κB p65 was associated with the intake of food rich in antioxidant active principles. Chronic exposure to low-dose benzene can modulate signal transduction pathways activated by oxidative stress and involved in cell proliferation and apoptosis. This could represent a possible mechanism of carcinogenic action of chronic benzene exposure. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Ambient air benzene at background sites in China's most developed coastal regions: exposure levels, source implications and health risks.

    Science.gov (United States)

    Zhang, Zhou; Wang, Xinming; Zhang, Yanli; Lü, Sujun; Huang, Zhonghui; Huang, Xinyu; Wang, Yuesi

    2015-04-01

    Benzene is a known human carcinogen causing leukemia, yet ambient air quality objectives for benzene are not available in China. The ambient benzene levels at four background sites in China's most developed coastal regions were measured from March 2012 to February 2013. The sites are: SYNECP, in the Northeast China Plain (NECP); YCNCP, in the North China Plain (NCP); THYRD, in the Yangtze River Delta (YRD) and DHPRD, in the Pearl River Delta (PRD). It was found that the mean annual benzene levels (578-1297 ppt) at the background sites were alarmingly higher, especially when compared to those of 60-480 pptv monitored in 28 cities in the United States. Wintertime benzene levels were significantly elevated at both sites (SYNECP and YCNCP) in northern China due to heating with coal/biofuels. Even at these background sites, the lifetime cancer risks of benzene (1.7-3.7E-05) all exceeded 1E-06 set by USEPA as acceptable for adults. At both sites in northern China, good correlations between benzene and CO or chloromethane, together with much lower toluene/benzene (T/B) ratios, suggested that benzene was largely related to coal combustion and biomass/biofuel burning. At the DHPRD site in the PRD, benzene revealed a highly significant correlation with methyl tert-butyl ether (MTBE), indicating that its source was predominantly from vehicle emissions. At the THYRD site in the YRD, higher T/B ratios and correlations between benzene and tetrachloroethylene, or MTBE, implied that benzene levels were probably affected by both traffic-related and industrial emissions. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Does maternal exposure to benzene and PM10 during pregnancy increase the risk of congenital anomalies? A population-based case-control study

    Science.gov (United States)

    Vinceti, Marco; Malagoli, Carlotta; Malavolti, Marcella; Cherubini, Andrea; Maffeis, Giuseppe; Rodolfi, Rossella; Heck, Julia E.; Astolfi, Gianni; Calzolari, Elisa; Nicolini, Fausto

    2015-01-01

    A few studies have suggested an association between maternal exposure to ambient air pollution from vehicular traffic and risk of congenital anomalies in the offspring, but epidemiologic evidence is neither strong nor entirely consistent. In a population-based case-control study in a Northern Italy community encompassing 228 cases of birth defects and 228 referent newborns, we investigated if maternal exposure to PM10 and benzene from vehicular traffic during early pregnancy, as estimated through a dispersion model, was associated with excess teratogenic risk. In conditional logistic regression analysis, and with adjustment for the other pollutant, we found that higher exposure to PM10 but not benzene was associated with increased risk of birth defects overall. Anomaly categories showing the strongest dose-response relation with PM10 exposure were musculoskeletal and chromosomal abnormalities but not cardiovascular defects, with Down syndrome being among the specific abnormalities showing the strongest association, though risk estimates particularly for the less frequent defects were statistically very unstable. Further adjustment in the regression model for potential confounders did not considerably alter the results. All the associations were stronger for average levels of PM10 than for their maximal level. Findings of this study give some support for an excess teratogenic risk following maternal exposure during pregnancy to PM10, but not benzene. Such association appears to be limited to some birth defect categories. PMID:26410719

  10. Occupational exposure to benzene: a prevention program for employees and contractors; PPEOB - Programa de Prevencao a Exposicao Ocupacional ao Benzeno para Empregados Proprios e Contratados

    Energy Technology Data Exchange (ETDEWEB)

    Moraes, Paulo Sergio de; Silva, Edson Ferreira da; Patto, Claudio Monteiro [TRANSPETRO, Rio de Janeiro, RJ (Brazil)

    2004-07-01

    PETROBRAS/TRANSPETRO Pipelines and Terminals has 500 regular employees and 5.064 out sourced workers in its Southeast Division. The out sourced employees work through 125 contracts involving a wide range of activities such as maintenance, operational, pipeline launching , engineering, administrative and auxiliary services. Among these workers, 200 people are subjected to benzene occupational exposure, which might be present in the products we transport in our pipelines. Benzene is recognized as a carcinogen according to ACGIH and Brazilian Ministry of Labour regulation NR- 15. Exposure to benzene in an uncontrolled way, be it chronic or sharp, may affect the worker's health such as: hematological alterations, neoplasys, neurobehavior alterations. Our program PPEOB (acronym in Portuguese for benzene occupational exposure prevention program) involved the work force and fosters health by anticipation, recognition, evaluation and control of the situations that may result in injuries. Further actions include the acquisition of equipment for benzene detection in the air or diluted in liquids and the introduction of new technologies for process control. The priority is the acquisition of equipment for collective protection not forgetting the individual protection equipment (IPE) and the required training. Implementation of this program counted with the effective participation of managers, contract supervisors and HSE professionals whose main task was to advise all involved parts. Furthermore, an auto-evaluation was released in order to assess the adherence of the PPEOB related to the facility reality. Since a suitable level of adherence is reached, the PPEOB can be used as a standard in the whole TRANSPETRO. (author)

  11. Formaldehyde and co-exposure with benzene induce compensation of bone marrow and hematopoietic stem/progenitor cells in BALB/c mice during post-exposure period

    International Nuclear Information System (INIS)

    Wei, Chenxi; Chen, Mouying; You, Huihui; Qiu, Feng; Wen, Huaxiao; Yuan, Junlin; Xiang, Shuanglin; Yang, Xu

    2017-01-01

    Formaldehyde (FA) is a human leukemogen. Since there is a latency period between initial FA exposure and the development of leukemia, the subsequent impact of FA on hematopoietic stem or progenitor cells (HSCs/HPCs) in post-exposure stage is crucial for a deep understanding of FA-induced hematotoxicity. BALB/c mice were exposed to 3 mg/m 3 FA for 2 weeks, mimicking occupational exposure, and were monitored for another 7 days post-exposure. Meanwhile, we included benzene (BZ) as a positive control, separately and together with FA because co-exposure occurs frequently. After 7-day recovery, colonies of progenitors for CFU-GM and BFU-E, and nucleated bone marrow cells in FA-exposed mice were comparable to controls, although they were significantly reduced during exposure. Levels of reactive oxygen species (ROS) and 8-hydroxy-2′-deoxyguanosine (8-OHdG) in CFU-GM and BFU-E from FA-exposed mice were higher than controls, although the increase in 8-OHdG was not significant. Granulocyte-macrophage colony stimulating factor (GM-CSF) level in the FA group was lower than controls, but the expression level for the receptor was not upregulated. It suggests that HSCs/HPCs in FA-exposed mice respond to a small amount of GM-CSF and proliferate rapidly, which may cause a possible risk of expansion of abnormal stem/progenitor cell clones. FA co-exposure with BZ was more potent for promoting CFU-GM formation and inducing ROS in BFU-E and 8-OHdG in CFU-GM during the post-exposure period. The compensation of myeloid progenitors with elevated ROS and 8-OHdG may lead to a risk of transforming normal HSCs/HPCs to leukemic stem/progenitor cells. Thus, co-exposure may pose a greater leukemia risk. - Highlights: • Nucleated bone marrow cell count recovered after 7 days post-FA and/or BZ exposure. • CFU-GM showed an increase in colonies and 8-OHdG after 7 days post-FA + BZ exposure. • Levels of ROS in CFU-GM and BFU-E were increased by FA or FA + BZ during recovery. • Levels of GM

  12. Anaerobic benzene degradation by bacteria.

    Science.gov (United States)

    Vogt, Carsten; Kleinsteuber, Sabine; Richnow, Hans-Hermann

    2011-11-01

    Benzene is a widespread and toxic contaminant. The fate of benzene in contaminated aquifers seems to be primarily controlled by the abundance of oxygen: benzene is aerobically degraded at high rates by ubiquitous microorganisms, and the oxygen-dependent pathways for its breakdown were elucidated more than 50 years ago. In contrast, benzene was thought to be persistent under anoxic conditions until 25 years ago. Nevertheless, within the last 15 years, several benzene-degrading cultures have been enriched under varying electron acceptor conditions in laboratories around the world, and organisms involved in anaerobic benzene degradation have been identified, indicating that anaerobic benzene degradation is a relevant environmental process. However, only a few benzene degraders have been isolated in pure culture so far, and they all use nitrate as an electron acceptor. In some highly enriched strictly anaerobic cultures, benzene has been described to be mineralized cooperatively by two or more different organisms. Despite great efforts, the biochemical mechanism by which the aromatic ring of benzene is activated in the absence of oxygen is still not fully elucidated; methylation, hydroxylation and carboxylation are discussed as likely reactions. This review summarizes the current knowledge about the 'key players' of anaerobic benzene degradation under different electron acceptor conditions and the possible pathway(s) of anaerobic benzene degradation. © 2011 The Authors; Journal compilation © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

  13. Benzene-Induced Aberrant miRNA Expression Profile in Hematopoietic Progenitor Cells in C57BL/6 Mice.

    Science.gov (United States)

    Wei, Haiyan; Zhang, Juan; Tan, Kehong; Sun, Rongli; Yin, Lihong; Pu, Yuepu

    2015-11-12

    Benzene is a common environmental pollutant that causes hematological alterations. MicroRNAs (miRNAs) may play a role in benzene-induced hematotoxicity. In this study, C57BL/6 mice showed significant hematotoxicity after exposure to 150 mg/kg benzene for 4 weeks. Benzene exposure decreased not only the number of cells in peripheral blood but also hematopoietic progenitor cells in the bone marrow. Meanwhile, RNA from Lin(-) cells sorted from the bone marrow was applied to aberrant miRNA expression profile using Illumina sequencing. We found that 5 miRNAs were overexpressed and 45 miRNAs were downregulated in the benzene exposure group. Sequencing results were confirmed through qRT-PCR. Furthermore, we also identified five miRNAs which significantly altered in Lin(-)c-Kit⁺ cells obtained from benzene-exposed mice, including mmu-miR-34a-5p; mmu-miR-342-3p; mmu-miR-100-5p; mmu-miR-181a-5p; and mmu-miR-196b-5p. In summary, we successfully established a classical animal model to induce significant hematotoxicity by benzene injection. Benzene exposure may cause severe hematotoxicity not only to blood cells in peripheral circulation but also to hematopoietic cells in bone marrow. Benzene exposure also alters miRNA expression in hematopoietic progenitor cells. This study suggests that benzene induces alteration in hematopoiesis and hematopoiesis-associated miRNAs.

  14. Anaerobic benzene degradation by bacteria

    Science.gov (United States)

    Vogt, Carsten; Kleinsteuber, Sabine; Richnow, Hans‐Hermann

    2011-01-01

    Summary Benzene is a widespread and toxic contaminant. The fate of benzene in contaminated aquifers seems to be primarily controlled by the abundance of oxygen: benzene is aerobically degraded at high rates by ubiquitous microorganisms, and the oxygen‐dependent pathways for its breakdown were elucidated more than 50 years ago. In contrast, benzene was thought to be persistent under anoxic conditions until 25 years ago. Nevertheless, within the last 15 years, several benzene‐degrading cultures have been enriched under varying electron acceptor conditions in laboratories around the world, and organisms involved in anaerobic benzene degradation have been identified, indicating that anaerobic benzene degradation is a relevant environmental process. However, only a few benzene degraders have been isolated in pure culture so far, and they all use nitrate as an electron acceptor. In some highly enriched strictly anaerobic cultures, benzene has been described to be mineralized cooperatively by two or more different organisms. Despite great efforts, the biochemical mechanism by which the aromatic ring of benzene is activated in the absence of oxygen is still not fully elucidated; methylation, hydroxylation and carboxylation are discussed as likely reactions. This review summarizes the current knowledge about the ‘key players’ of anaerobic benzene degradation under different electron acceptor conditions and the possible pathway(s) of anaerobic benzene degradation. PMID:21450012

  15. Leukemia and Benzene

    Science.gov (United States)

    Snyder, Robert

    2012-01-01

    Excessive exposure to benzene has been known for more than a century to damage the bone marrow resulting in decreases in the numbers of circulating blood cells, and ultimately, aplastic anemia. Of more recent vintage has been the appreciation that an alternative outcome of benzene exposure has been the development of one or more types of leukemia. While many investigators agree that the array of toxic metabolites, generated in the liver or in the bone marrow, can lead to traumatic bone marrow injury, the more subtle mechanisms leading to leukemia have yet to be critically dissected. This problem appears to have more general interest because of the recognition that so-called “second cancer” that results from prior treatment with alkylating agents to yield tumor remissions, often results in a type of leukemia reminiscent of benzene-induced leukemia. Furthermore, there is a growing literature attempting to characterize the fine structure of the marrow and the identification of so called “niches” that house a variety of stem cells and other types of cells. Some of these “niches” may harbor cells capable of initiating leukemias. The control of stem cell differentiation and proliferation via both inter- and intra-cellular signaling will ultimately determine the fate of these transformed stem cells. The ability of these cells to avoid checkpoints that would prevent them from contributing to the leukemogenic response is an additional area for study. Much of the study of benzene-induced bone marrow damage has concentrated on determining which of the benzene metabolites lead to leukemogenesis. The emphasis now should be directed to understanding how benzene metabolites alter bone marrow cell biology. PMID:23066403

  16. Genome-Wide Functional Profiling Reveals Genes Required for Tolerance to Benzene Metabolites in Yeast

    Science.gov (United States)

    North, Matthew; Tandon, Vickram J.; Thomas, Reuben; Loguinov, Alex; Gerlovina, Inna; Hubbard, Alan E.; Zhang, Luoping; Smith, Martyn T.; Vulpe, Chris D.

    2011-01-01

    Benzene is a ubiquitous environmental contaminant and is widely used in industry. Exposure to benzene causes a number of serious health problems, including blood disorders and leukemia. Benzene undergoes complex metabolism in humans, making mechanistic determination of benzene toxicity difficult. We used a functional genomics approach to identify the genes that modulate the cellular toxicity of three of the phenolic metabolites of benzene, hydroquinone (HQ), catechol (CAT) and 1,2,4-benzenetriol (BT), in the model eukaryote Saccharomyces cerevisiae. Benzene metabolites generate oxidative and cytoskeletal stress, and tolerance requires correct regulation of iron homeostasis and the vacuolar ATPase. We have identified a conserved bZIP transcription factor, Yap3p, as important for a HQ-specific response pathway, as well as two genes that encode putative NAD(P)H:quinone oxidoreductases, PST2 and YCP4. Many of the yeast genes identified have human orthologs that may modulate human benzene toxicity in a similar manner and could play a role in benzene exposure-related disease. PMID:21912624

  17. Evaluation of benzene exposure in petrol pump attendants and in mechanics by urinary trans, trans-muconic acid (t, t-MA determination

    Directory of Open Access Journals (Sweden)

    Teresa Cirillo

    2004-12-01

    Full Text Available

    Occupational exposure to benzene in petrol pump attendants and in mechanics was studied by examining the benzene content in both the air breathed and in the urinary metabolite trans,trans-muconic acid (t,t-MA. Thirty petrol pump attendants and thirty mechanics (as exposed workers and thirty adult male office workers (as non exposed workers were involved in the study. Measures were taken at the begin and at the end of the working shifts.

     The benzene concentrations in the breathing air samples varied from 2 to 88 μg m-3, lower than the EU acceptable limit for occupational environment. The average urinary t,t-MA in the petrol pump attendants at the begin and at the end of the working shifts ranged between 133 ± 69 and 255 ± 174 μg g-1 creatinine and in the mechanics between 204 ± 139 and 300 ± 211 μg g-1 creatinine, respectively.

    In all the participants the mean levels of urinary t,t-MA at the end of the working shifts were significantly higher than those at the beginning. In the exposed workers mean levels of urinary t,t-MA were significantly higher than in those of the non-exposed workers. The influence of the smoking was demonstrated by the urinary t,t-MA levels in smoking non-exposed subjects.

  18. An efficient analytical method for determination of S-phenylmercapturic acid in urine by HPLC fluorimetric detector to assessing benzene exposure.

    Science.gov (United States)

    Mendes, Michele P Rocha; Silveira, Josianne Nicácio; Andre, Leiliane Coelho

    2017-09-15

    Benzene is an important occupational and environmental contaminant, naturally present in petroleum and as by-product in the steel industry. Toxicological studies showed pronounced myelotoxic action, causing leukemic and others blood cells disorders. Assessing of benzene exposure is performed by biomarkers as trans, trans-muconic acid (AttM) and S-phenylmercapturic acid (S-PMA) in urine. Due to specificity of S-PMA, this biomarker has been proposed to asses lower levels of benzene in air. The aim of this study was to validate an analytical method for the quantification of S-PMA by High-Performance Liquid Chromatography with fluorometric detector. The development of an analytical method of S-PMA in urine was carried out by solid phase extraction (SPE) using C-18 phase. The eluated were submitted to water bath at 75°C and nitrogen to analyte concentration, followed by alkaline hydrolysis and derivatization with monobromobimane. The chromatography conditions were reverse phase C-18 column (240mm, 4mm and 5μm) at 35°C; acetonitrile and 0.5% acetic acid (50:50) as mobile phase with a flow of 0.8mL/min. The limits of detection and quantification were 0.22μg/L and 0.68μg/L, respectively. The linearity was verified by simple linear regression, and the method exhibited good linearity in the range of 10-100μg/L. There was no matrix effect for S-PMA using concentrations of 40, 60, 80 and 100μg/L. The intra- and interassay precision showed coefficient of variation of less than 10% and the recovery ranged from 83.4 to 102.8% with an average of 94.4%. The stability of S-PMA in urine stored at -20°C was of seven weeks. The conclusion is that this method presents satisfactory results per their figures of merit. This proposed method for determining urinary S-PMA showed adequate sensitivity for assessment of occupational and environmental exposure to benzene using S-PMA as biomarker of exposure. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. [Exposure to benzene and hematologic changes in workers at the Ina-Oki Drnisplast factory in Drnis].

    Science.gov (United States)

    Mikulandra, O; Cala, D; Marković, V; Zorić, A

    1993-12-01

    In the summer of 1984 workers in the "INA-OKI Drnisplast" factory frequently complained about headaches, weight loss and irregular menstrual cycles. According to the factory engineers that might have been due to an altered composition of the paints and glues that were used in the manufacturing process that year. Those had been found to lack specifications of chemical composition. Experts from the Institute for the Safety at Work from Zagreb were called in to perform measurements of organic solvents content in the workroom air. Benzene concentrations were found to be up to five times higher than the maximum permissible levels, those of toluene up to three times and of cyclohexane up to ten times higher. The polluted part of the factory was closed down, changes were introduced into the working process (use of paints was stopped, only glues without benzene content were allowed and proper ventilation was installed) and all the workers, twenty in all, received medical treatment. After three months the working process was resumed. In 1989 all the twenty workers underwent a control medical examination. All showed signs of recovery, both objective and subjective. Their blood tests values were within normal range. All the workers continued working, save one who retired in 1988 upon recommendation of a disability commission. The cause of disablement was occupational disease--benzene poisoning. On the basis of this experience emphasis is placed on the importance, in working with benzene, of complying with the Legislation on working capacity assessment for jobs requiring special working conditions and with the Safety at work act.

  20. Identifying and managing adverse environmental health effects: 3. Lead exposure

    Science.gov (United States)

    Sanborn, Margaret D.; Abelsohn, Alan; Campbell, Monica; Weir, Erica

    2002-01-01

    LEAD LEVELS IN NORTH AMERICAN CHILDREN AND ADULTS have declined in the past 3 decades, but lead persists in the environment in lead paint, old plumbing and contaminated soil. There are also a number of occupations and hobbies that carry a high risk of lead exposure. There is no evidence for a threshold below which lead has no adverse health effects. Blood lead levels previously considered safe are now known to cause subtle, chronic health effects. The health effects of lead exposure include developmental neurotoxicity, reproductive dysfunction and toxicity to the kidneys, blood and endocrine systems. Most lead exposures are preventable, and diagnosing lead poisoning is relatively simple compared with diagnosing health effects of exposures to other environmental toxins. Accurate assessment of lead poisoning requires specific knowledge of the sources, high-risk groups and relevant laboratory tests. In this article we review the multiple, systemic toxic effects of lead and provide current information on groups at risk, prevention, diagnosis and clinical treatment. We illustrate how the CH2OPD2 mnemonic (Community, Home, Hobbies, Occupation, Personal habits, Diet and Drugs) and specific screening questions are useful tools for physicians to quickly obtain an environmental exposure history and identify patients at high risk of lead exposure. By applying effective primary prevention, case-finding and treatment interventions for lead exposure, both the individual patient and the larger community reap the benefits of better health. PMID:12041847

  1. Reactions of benzene oxide with thiols including glutathione.

    Science.gov (United States)

    Henderson, Alistair P; Barnes, Martine L; Bleasdale, Christine; Cameron, Richard; Clegg, William; Heath, Sarah L; Lindstrom, Andrew B; Rappaport, Stephen M; Waidyanatha, Suramya; Watson, William P; Golding, Bernard T

    2005-02-01

    S-Phenylmercapturic acid is a minor metabolite of benzene used as a biomarker for human benzene exposures. The reaction of intracellular glutathione with benzene oxide-oxepin, the initial metabolite of benzene, is presumed to give 1-(S-glutathionyl)-cyclohexa-3,5-dien-2-ol, which undergoes dehydration to S-phenylglutathione, the precursor of S-phenylmercapturic acid. To validate the proposed route to S-phenylglutathione, reactions of benzene oxide-oxepin with glutathione and other sulfur nucleophiles have been studied. The reaction of benzene oxide with an excess of aqueous sodium sulfide, followed by acetylation, gave bis-(6-trans-5-acetoxycyclohexa-1,3-dienyl)sulfide, the structure of which was proved by X-ray crystallography. Reactions of benzene oxide-oxepin in a 95:5 (v/v) mixture of phosphate buffer in D2O with (CD3)2SO were monitored by 1H NMR spectroscopy. In the absence of glutathione, the half-life of benzene oxide-oxepin was ca. 34 min at 25 degrees C and pD 7.0. The half-life was not affected in the range of 2-15 mM glutathione in the presence and absence of a commercial sample of human glutathione S-transferase (at pH 7.0, 8.0, 8.5, or 10.0). The adduct 1-(S-glutathionyl)-cyclohexa-3,5-diene-2-ol was identified in these reaction mixtures, especially at higher pH, by mass spectrometry and by its acid-catalyzed decomposition to S-phenylglutathione. Incubation of benzene oxide with N-acetyl-L-cysteine at 37 degrees C and pH 10.0 and subsequent mass spectrometric analysis of the mixture showed formation of pre-S-phenylmercapturic acid and the dehydration product, S-phenylmercapturic acid. The data validate the premise that benzene oxide-oxepin can be captured by glutathione to give (1R,2R)- and/or (1S,2S)-1-(S-glutathionyl)-cyclohexa-3,5-dien-2-ol, which dehydrate to S-phenylglutathione. The capture is a relatively inefficient process at pH 7 that is accelerated at higher pH. These studies account for the observation that the metabolism of benzene is

  2. Bioremediation of Benzene-contaminated Underground Aquifers

    Science.gov (United States)

    Watanabe, Kazuya; Takahata, Yoh

    Contamination of underground aquifers with gasoline occurs frequently. Among the gasoline constituents, benzene is of great environmental concern, since it is carcinogenic, water-soluble and persistent under anaerobic conditions. We have analyzed a gasoline-contaminated underground aquifer undergoing natural attenuation, where benzene was degraded, albeit slowly, under anaerobic conditions. RNA-based stable-isotope probing identified that bacteria affiliated with the genus AZOARCUS was responsible for benzene degradation under nitrate-reducing conditions. This result was confirmed by isolating an anaerobic benzene-degrading bacterium AZOARCUS sp. strain DN11. This strain degraded benzene at relatively low concentrations (as low as 10 ppb). It could also degrade toluene and xylenes. In laboratory bioaugmentation experiments using benzene-contaminated groundwater, it was demonstrated that supplementation with DN11 significantly accelerated benzene degradation under a nitrate-reducing condition. These results indicate that DN11 is potentially useful for degrading benzene that contaminates underground aquifers at relatively low concentrations.

  3. Increased leukemia-associated gene expression in benzene-exposed workers

    Science.gov (United States)

    Li, Keqiu; Jing, Yaqing; Yang, Caihong; Liu, Shasha; Zhao, Yuxia; He, Xiaobo; Li, Fei; Han, Jiayi; Li, Guang

    2014-01-01

    Long-term exposure to benzene causes several adverse health effects, including an increased risk of acute myeloid leukemia. This study was to identify genetic alternations involved in pathogenesis of leukemia in benzene-exposed workers without clinical symptoms of leukemia. This study included 33 shoe-factory workers exposed to benzene at levels from 1 ppm to 10 ppm. These workers were divided into 3 groups based on the benzene exposure time, 1- benzene exposure history were recruited as controls. Cytogenetic analysis using Affymetrix Cytogenetics Array found copy-number variations (CNVs) in several chromosomes of benzene-exposed workers. Expression of targeted genes in these altered chromosomes, NOTCH1 and BSG, which play roles in leukemia pathogenesis, was further examined using real-time PCR. The NOTCH1 mRNA level was significantly increased in all 3 groups of workers, and the NOTCH1 mRNA level in the 12- benzene-exposed workers. PMID:24993241

  4. Exposure of Tg.AC transgenic mice to benzene suppresses hematopoietic progenitor cells and alters gene expression in critical signaling pathways

    International Nuclear Information System (INIS)

    Nwosu, Veronica C.; Kissling, Grace E.; Trempus, Carol S.; Honeycutt, Hayden; French, John E.

    2004-01-01

    The effects of acute benzene (BZ) exposure on hematopoietic progenitor cells (HPCs) derived from bone marrow cells were studied using homozygous male v-Ha-ras Tg.AC mice at 8-10 weeks of age. The mice were given 0.02% BZ in their drinking water for 28 days with the dose rate estimated to be 34 mg benzene/kg BW/day. Analysis of cultured HPCs indicated that BZ suppressed the proliferation of the multilineage colony forming unit-granulocyte, erythrocyte, macrophage, megakaryocyte (CFU-GEMM); colony forming unit-granulocyte, macrophage (CFU-GM); and blast forming unit erythrocyte/colony forming unit erythrocyte (BFUE/CFUE). A gene expression profile was generated using nylon arrays spotted with 23 cDNAs involved in selected signal pathways involved in cell distress, inflammation, DNA damage, cell cycle arrest, and apoptosis. Of the 23 marker genes, 6 (bax, c-fos, E124, hsf1, ikBa, and p57) were significantly (Mann-Whitney U tests, P < 0.05) overexpressed in BZ-exposed mice. Two genes (c-myc and IL-2) approached significance (at P = 0.053). The pattern of gene expression was consistent with BZ toxicity and the suppression of HPCs

  5. Peer Review Comments on the IRIS Assessment of Benzene

    Science.gov (United States)

    Attachment to IRIS file for benzene, January 19, 2000, RESPONSE TO THE PEER REVIEW COMMENTS, II. Extrapolation of the Benzene Inhalation Unit Risk Estimate to the Oral Route of Exposure (EPA/NCEA-W-0517, July 1999)

  6. Fuel Dependence of Benzene Pathways

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, H; Eddings, E; Sarofim, A; Westbrook, C

    2008-07-14

    The relative importance of formation pathways for benzene, an important precursor to soot formation, was determined from the simulation of 22 premixed flames for a wide range of equivalence ratios (1.0 to 3.06), fuels (C{sub 1}-C{sub 12}), and pressures (20 to 760 torr). The maximum benzene concentrations in 15 out of these flames were well reproduced within 30% of the experimental data. Fuel structural properties were found to be critical for benzene production. Cyclohexanes and C{sub 3} and C{sub 4} fuels were found to be among the most productive in benzene formation; and long-chain normal paraffins produce the least amount of benzene. Other properties, such as equivalence ratio and combustion temperatures, were also found to be important in determining the amount of benzene produced in flames. Reaction pathways for benzene formation were examined critically in four premixed flames of structurally different fuels of acetylene, n-decane, butadiene, and cyclohexane. Reactions involving precursors, such as C{sub 3} and C{sub 4} species, were examined. Combination reactions of C{sub 3} species were identified to be the major benzene formation routes with the exception of the cyclohexane flame, in which benzene is formed exclusively from cascading fuel dehydrogenation via cyclohexene and cyclohexadiene intermediates. Acetylene addition makes a minor contribution to benzene formation, except in the butadiene flame where C{sub 4}H{sub 5} radicals are produced directly from the fuel, and in the n-decane flame where C{sub 4}H{sub 5} radicals are produced from large alkyl radical decomposition and H atom abstraction from the resulting large olefins.

  7. Subclinical effects of groundwater contaminants. Pt. 3. Effects of repeated oral exposure to combinations of benzene and toluene on immunologic responses in mice

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, G.C.; Parker, R.D.R. (Utah State Univ., Logan (USA). Dept. of Biology); Sharma, R.P.; Hughes, B.J. (Utah Univ., Logan, UT (USA). Dept. of Animal, Dairy and Veterinary Sciences)

    1990-06-01

    Toxicity of environmental pollutants may be expressed as combined effects of chemicals. Benzene, a proven hematotoxic agent, frequently occurs with toluene in cocontaminated groundwater. Groups of CD-1 male mice were exposed continuously for 4 weeks to benzene (166 mg/l), toluene (80 and 325 mg/l), and combinations of benzene (166 mg/l) + toluene (80 mg/l or 325 mg/l) in drinking water. Benzene-induced anemia was alleviated by simultaneous toluene treatment. Leukopenia and lymphopenia were observed in the case of benzene only and benzene + toluene (80 mg/l)-treated mice. The cytopenia, however, was less severe in the benzen + toluene (325 mg/l)-treated group. Immunotoxicity induced by benzene treatment alone was characterized by involution of thymic mass and suppressions of both B- and T-cell mitogeneses, mixed lymphocyte culture response to alloantigens, the tumor lytic ability of cytotoxic T-lymphocytes as determined by {sup 51}Cr-release assay, and antibody production response to T-dependent antigen (sheep red blood cells). IL-2 secretion by Con A-stimulated mouse T-cells was decreased in the benzene-treated group. Toluene (325 mg/l) completely inhibited these adverse effects when it was coadministered with benzene, while the low dose of toluene (80 mg/l) did not protect against benzene-induced depressions of immune functions. Toluene administered alone at levels up to 325 mg/l showed no abvious immunotoxic effects. Results of this study demonstrated that toluene, in sufficient amounts, has an antagonistic effect on benzene immunotoxicity. (orig.).

  8. Benzene and lymphohematopoietic malignancies in humans.

    Science.gov (United States)

    Hayes, R B; Songnian, Y; Dosemeci, M; Linet, M

    2001-08-01

    Quantitative evaluations of benzene-associated risk for cancer have relied primarily on findings from a cohort study of highly exposed U.S. rubber workers. An epidemiologic investigation in China (NCI/CAPM study) extended quantitative evaluations of cancer risk to a broader range of benzene exposures, particularly at lower levels. We review the evidence implicating benzene in the etiology of hematopoietic disorders, clarify methodologic aspects of the NCI/CAPM study, and examine the study in the context of the broader literature on health effects associated with occupational benzene exposure. Quantitative relationships for cancer risk from China and the U.S. show a relatively smooth increase in risk for acute myeloid leukemia and related conditions over a broad dose range of benzene exposure (below 200 ppm-years mostly from the China study and above 200 ppm-years mostly from the U.S. study). Risks of acute myeloid leukemia and other malignant and nonmalignant hematopoietic disorders associated with benzene exposure in China are consistent with other information about benzene exposure, hematotoxicity, and cancer risk, extending evidence for hematopoietic cancer risks to levels substantially lower than had previously been established. Published 2001 Wiley-Liss, Inc.

  9. Benzene formation in electronic cigarettes.

    Directory of Open Access Journals (Sweden)

    James F Pankow

    Full Text Available The heating of the fluids used in electronic cigarettes ("e-cigarettes" used to create "vaping" aerosols is capable of causing a wide range of degradation reaction products. We investigated formation of benzene (an important human carcinogen from e-cigarette fluids containing propylene glycol (PG, glycerol (GL, benzoic acid, the flavor chemical benzaldehyde, and nicotine.Three e-cigarette devices were used: the JUULTM "pod" system (provides no user accessible settings other than flavor cartridge choice, and two refill tank systems that allowed a range of user accessible power settings. Benzene in the e-cigarette aerosols was determined by gas chromatography/mass spectrometry. Benzene formation was ND (not detected in the JUUL system. In the two tank systems benzene was found to form from propylene glycol (PG and glycerol (GL, and from the additives benzoic acid and benzaldehyde, especially at high power settings. With 50:50 PG+GL, for tank device 1 at 6W and 13W, the formed benzene concentrations were 1.9 and 750 μg/m3. For tank device 2, at 6W and 25W, the formed concentrations were ND and 1.8 μg/m3. With benzoic acid and benzaldehyde at ~10 mg/mL, for tank device 1, values at 13W were as high as 5000 μg/m3. For tank device 2 at 25W, all values were ≤~100 μg/m3. These values may be compared with what can be expected in a conventional (tobacco cigarette, namely 200,000 μg/m3. Thus, the risks from benzene will be lower from e-cigarettes than from conventional cigarettes. However, ambient benzene air concentrations in the U.S. have typically been 1 μg/m3, so that benzene has been named the largest single known cancer-risk air toxic in the U.S. For non-smokers, chronically repeated exposure to benzene from e-cigarettes at levels such as 100 or higher μg/m3 will not be of negligible risk.

  10. Benzene formation in electronic cigarettes.

    Science.gov (United States)

    Pankow, James F; Kim, Kilsun; McWhirter, Kevin J; Luo, Wentai; Escobedo, Jorge O; Strongin, Robert M; Duell, Anna K; Peyton, David H

    2017-01-01

    The heating of the fluids used in electronic cigarettes ("e-cigarettes") used to create "vaping" aerosols is capable of causing a wide range of degradation reaction products. We investigated formation of benzene (an important human carcinogen) from e-cigarette fluids containing propylene glycol (PG), glycerol (GL), benzoic acid, the flavor chemical benzaldehyde, and nicotine. Three e-cigarette devices were used: the JUULTM "pod" system (provides no user accessible settings other than flavor cartridge choice), and two refill tank systems that allowed a range of user accessible power settings. Benzene in the e-cigarette aerosols was determined by gas chromatography/mass spectrometry. Benzene formation was ND (not detected) in the JUUL system. In the two tank systems benzene was found to form from propylene glycol (PG) and glycerol (GL), and from the additives benzoic acid and benzaldehyde, especially at high power settings. With 50:50 PG+GL, for tank device 1 at 6W and 13W, the formed benzene concentrations were 1.9 and 750 μg/m3. For tank device 2, at 6W and 25W, the formed concentrations were ND and 1.8 μg/m3. With benzoic acid and benzaldehyde at ~10 mg/mL, for tank device 1, values at 13W were as high as 5000 μg/m3. For tank device 2 at 25W, all values were ≤~100 μg/m3. These values may be compared with what can be expected in a conventional (tobacco) cigarette, namely 200,000 μg/m3. Thus, the risks from benzene will be lower from e-cigarettes than from conventional cigarettes. However, ambient benzene air concentrations in the U.S. have typically been 1 μg/m3, so that benzene has been named the largest single known cancer-risk air toxic in the U.S. For non-smokers, chronically repeated exposure to benzene from e-cigarettes at levels such as 100 or higher μg/m3 will not be of negligible risk.

  11. A critique of the exposure assessment in the epidemiologic study of benzene-exposed workers in China conducted by the Chinese Academy of Preventive Medicine and the US National Cancer Institute.

    Science.gov (United States)

    Wong, O

    1999-12-01

    As reviewed in some detail in the present paper, workers employed in a wide variety of industries were included in the Chinese benzene study, and were exposed to not only benzene but also a wide range of other industrial chemicals. To attribute any or all health effects observed in the exposed cohort to benzene without examining other concomitant exposures is not appropriate. Although it was stated that one of the major objectives of the expanded study was to examine the effects of other risk factors, no such examination was made in any of the analyses in the expanded CAPM-NCI study. The CAPM-NCI study suffered from a number of limitations. One of the most serious limitations of the study involved the exposure estimates developed by the US NCI team. Comparing the assumptions used in the development of estimates and the exposure estimates themselves to actual data reported previously by the Chinese investigators revealed numerous inconsistencies and, in many cases, large discrepancies. It appeared that the exposure estimates were consistently lower than the actual exposure data. The so-called indirect validation conducted by the NCI team served no useful purpose, since by definition it could not validate the absolute values of the estimates. NCI was fully aware of some of the inadequacies of its exposure estimates. Although in a 1994 paper, the NCI team recognized that little confidence could be attached to the estimated (e.g., only 2% of the estimates for the time interval 1949-1959 and only 6% of the estimates prior to 1975 were rated in the high confidence category), the inadequacy of the estimates was never mentioned or discussed in any subsequent analyses or in the latest report (Hayes et al., 1998). Instead, the exposure of the workers was hailed as "well characterized" (Hayes et al., 1998). In conclusion both CAPM and NCI have made substantial efforts in studying the relationship between benzene exposure and various malignancies. Unfortunately, there were

  12. Benzene observations and source appointment in a region of oil and natural gas development

    Science.gov (United States)

    Halliday, Hannah Selene

    Benzene is a primarily anthropogenic volatile organic compound (VOC) with a small number of well characterized sources. Atmospheric benzene affects human health and welfare, and low level exposure (air quality within the Wattenburg Gas Field (WGF) in the Denver-Julesburg Basin. The measurements were carried out in July and August 2014 as part of NASA's DISCOVER-AQ field campaign. The PTR-QMS data were supported by pressurized whole air canister samples and airborne vertical and horizontal surveys of VOCs. Unexpectedly high benzene mixing ratios were observed at PAO at ground level (mean benzene = 0.53 ppbv, maximum benzene = 29.3 ppbv), primarily at night (mean nighttime benzene = 0.73 ppbv). These high benzene levels were associated with southwesterly winds. The airborne measurements indicate that benzene originated from within the WGF, and typical source signatures detected in the canister samples implicate emissions from O&NG activities rather than urban vehicular emissions as primary benzene source. This conclusion is backed by a regional toluene-to-benzene ratio analysis which associated southerly flow with vehicular emissions from the Denver area. Weak benzene-to-CO correlations confirmed that traffic emissions were not responsible for the observed high benzene levels. Previous measurements at the Boulder Atmospheric Observatory (BAO) and our data obtained at PAO allow us to locate the source of benzene enhancements between the two atmospheric observatories. Fugitive emissions of benzene from O&NG operations in the Platteville area are discussed as the most likely causes of enhanced benzene levels at PAO. A limited information source attribution with the PAO dataset was completed using the EPA's positive matrix factorization (PMF) source receptor model. Six VOCs from the PTR-QMS measurement were used along with CO and NO for a total of eight chemical species. Six sources were identified in the PMF analysis: a primarily CO source, an aged vehicle emissions

  13. 40 CFR 721.1350 - Benzene, (1-methylethyl)(2-phenylethyl)-.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzene, (1-methylethyl)(2-phenylethyl... Substances § 721.1350 Benzene, (1-methylethyl)(2-phenylethyl)-. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified as benzene, (1-methylethyl)(2...

  14. 40 CFR 721.1210 - Benzene, (2-chloroethoxy)-.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzene, (2-chloroethoxy)-. 721.1210... Substances § 721.1210 Benzene, (2-chloroethoxy)-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as benzene, (2-chloroethoxy)- (PMN P-87-1471) is subject to...

  15. Transcriptomics analysis of interactive effects of benzene, trichloroethylene and methyl mercury within binary and ternary mixtures on the liver and kidney following subchronic exposure in the rat

    International Nuclear Information System (INIS)

    Hendriksen, Peter J.M.; Freidig, Andreas P.; Jonker, Diana; Thissen, Uwe; Bogaards, Jan J.P.; Mumtaz, Moiz M.; Groten, John P.; Stierum, Rob H.

    2007-01-01

    The present research aimed to study the interaction of three chemicals, methyl mercury, benzene and trichloroethylene, on mRNA expression alterations in rat liver and kidney measured by microarray analysis. These compounds were selected based on presumed different modes of action. The chemicals were administered daily for 14 days at the Lowest-Observed-Adverse-Effect-Level (LOAEL) or at a two- or threefold lower concentration individually or in binary or ternary mixtures. The compounds had strong antagonistic effects on each other's gene expression changes, which included several genes encoding Phase I and II metabolizing enzymes. On the other hand, the mixtures affected the expression of 'novel' genes that were not or little affected by the individual compounds. The three compounds exhibited a synergistic interaction on gene expression changes at the LOAEL in the liver and both at the sub-LOAEL and LOAEL in the kidney. Many of the genes induced by mixtures but not by single compounds, such as Id2, Nr2f6, Tnfrsf1a, Ccng1, Mdm2 and Nfkb1 in the liver, are known to affect cellular proliferation, apoptosis and tissue-specific function. This indicates a shift from compound specific response on exposure to individual compounds to a more generic stress response to mixtures. Most of the effects on cell viability as concluded from transcriptomics were not detected by classical toxicological endpoints illustrating the benefit of increased sensitivity of assessing gene expression profiling. These results emphasize the benefit of applying toxicogenomics in mixture interaction studies, which yields biomarkers for joint toxicity and eventually can result in an interaction model for most known toxicants

  16. A comprehensive study of benzene concentrations and emissions in Houston

    Science.gov (United States)

    Müller, Markus; Eichler, Philipp; Berk Knighton, W.; Estes, Mark; Crawford, James H.; Mikoviny, Tomas; Wisthaler, Armin

    2014-05-01

    The Houston Metropolitan Area (Greater Houston) has a population of over 6 million people, it ranks among the three fastest growing metropolises in the developed world and population growth scenarios predict it to reach megacity status in the coming two to four decades. Greater Houston is home to the largest petrochemical-manufacturing complex in the world with important consequences for the environment in the region. Direct and fugitive emissions of hydrocarbons adversely affect Houston's air quality which has been subject to intense studies over the past two decades. In 2013, NASA conducted the DISCOVER-AQ field campaign in support of developing a satellite-based capability to assess Houston's air quality in the future. Amongst other measurements, airborne, mobile ground-based and stationary ground-based measurements of benzene were carried out. Benzene is a carcinogenic air toxic with strict exposure regulations in the U.S. and in Europe. We have used the obtained comprehensive dataset to map benzene concentrations in the Houston metropolitan area, locate and identify point sources, compare industrial and traffic emissions and put them in relation to previous measurements and emission inventories. The obtained data will allow a better assessment of health risks associated with benzene exposure in a large metropolitan area that includes both traffic and industrial benzene sources. This work was funded by BMVIT / FFG-ALR in the frame of the Austrian Space Application Programme (ASAP 8, project 833451). PE was funded through the PIMMS ITN (EU-FP7, agreement number 287382). Additional resources were provided through NASA's Earth Venture program (EV-1) and the NASA Postdoctoral Program (NPP). We want to thank Scott Herndon and Aerodyne Research for their support.

  17. Benzene: questions and answers

    International Nuclear Information System (INIS)

    1999-01-01

    This information booklet is intended to inform residents near natural gas dehydration facilities about benzene and its levels in the atmosphere. It was issued following the federal government's decision to place benzene on its Priority Substances List and to require industry to establish means for reducing benzene emissions from natural gas dehydrators and to inform residents about benzene emissions from glycol dehydration facilities. Accordingly, the booklet explains what benzene is (a colourless flammable liquid component of hydrocarbons) how it gets into the air (during gasoline refining, vehicle refueling and the production of steel and petrochemicals), the associated health hazards (a recognized carcinogen, causing an increased incidence of leukemia in concentrations of 100 parts per million), defines a glycol dehydrator (a facility built at or near some natural gas fields for the removal of water from the natural gas to prevent corrosion and freezing of pipelines), and enumerates the steps that are being taken to reduce benzene levels in the air (benzene levels in gasoline have been reduced, along with benzene emissions from petrochemical plants, refineries, steel plants and glycol dehydrators by 54 per cent to date; this will rise to 90 per cent by 2005). In addition to these actions, industry plans call for all existing glycol dehydrators within 750 metres of any permanent residence to be limited to benzene emissions of no more than three tonnes per year before 2001; new glycol dehydrators after that date will be expected to have benzene emissions reduced to the lowest level that can be practically achieved

  18. Benzene monitoring at CPPI service stations

    International Nuclear Information System (INIS)

    Davis, C.S.

    1996-01-01

    A study was conducted in which ambient airborne concentration levels of benzene were measured at a representative set of gasoline service stations in Toronto and Vancouver. Benzene is considered to be toxic under the Canadian Environmental Protection Act (CEPA). It is a component in gasoline (0.1 to 4.7 per cent by volume) and is present in vehicle evaporative and exhaust emissions. Measurements were made every 18 days at each station for one year. The objective of the study was to assess the ambient and employee exposure levels of benzene at service stations and to determine whether the levels were typical of those published in the literature. In a 1986 PACE (Petroleum Association for Conservation of the Canadian Environment) survey of exposure to gasoline hydrocarbon vapours at Canadian service stations, airborne benzene concentration data was inconsistent with similar ambient and personal exposure data in the international literature. It was concluded that both the mean ambient benzene concentration and the personal exposure level measurements in this study were generally lower than similar measurements made in other countries. The same observation was made with respect to ambient and personal exposure levels measured in this study vis-a-vis those measured during the PACE study conducted in 1985/86. . 31 refs., 24 tabs., 5 figs

  19. Benzene and childhood acute leukemia in Oklahoma.

    Science.gov (United States)

    Janitz, Amanda E; Campbell, Janis E; Magzamen, Sheryl; Pate, Anne; Stoner, Julie A; Peck, Jennifer D

    2017-10-01

    Although childhood cancer is a leading cause of childhood mortality in the US, evidence regarding the etiology is lacking. The goal of this study was to evaluate the association between benzene, a known carcinogen, and childhood acute leukemia. We conducted a case-control study including cases diagnosed with acute leukemia between 1997 and 2012 (n = 307) from the Oklahoma Central Cancer Registry and controls matched on week of birth from birth certificates (n = 1013). We used conditional logistic regression to evaluate the association between benzene, measured with the 2005 National-Scale Air Toxics Assessment (NATA) at census tract of the birth residence, and childhood acute leukemia. We observed no differences in benzene exposure overall between cases and controls. However, when stratified by year of birth, cases born from 2005 to 2010 had a three-fold increased unadjusted odds of elevated exposure compared to controls born in this same time period (4th Quartile OR: 3.53, 95% CI: 1.35, 9.27). Furthermore, the estimates for children with acute myeloid leukemia (AML) were stronger than those with acute lymphoid leukemia, though not statistically significant. While we did not observe an association between benzene and childhood leukemia overall, our results suggest that acute leukemia is associated with increased benzene exposure among more recent births, and children with AML may have increased benzene exposure at birth. Using the NATA estimates allowed us to assess a specific pollutant at the census tract level, providing an advantage over monitor or point source data. Our study, however, cannot rule out the possibility that benzene may be a marker of other traffic-related exposures and temporal misclassification may explain the lack of an association among earlier births. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Identifying occupational and nonoccupational exposure to mercury in dental personnel.

    Science.gov (United States)

    Shirkhanloo, Hamid; Fallah Mehrjerdi, Mohammad Ali; Hassani, Hamid

    2017-03-04

    The objective of this study was to investigate the occupational and nonoccupational exposure to mercury (Hg) vapor in dental personnel by examining the relationships between blood mercury, urine mercury, and their ratio with air mercury. The method was performed on 50 occupational exposed and 50 unexposed controls (25 men and 25 women). The mercury concentrations in air and human biological samples were determined based on the National Institute for Occupational Safety and Health (NIOSH) method and standard method (SM) by a new mode of liquid-phase microextraction, respectively. The mean mercury concentrations in urine (μg Hg 0 /g creatinine) and blood were significantly higher than control group, respectively (19.41 ± 5.18 vs 2.15 ± 0.07 μg/g and 16.40 ± 4.97 vs 2.50 ± 0.02 μg/L) (p mercury concentration in blood/urine ratio (r = .380) with dental office air are new indicators for assessing occupational exposure in dental personnel.

  1. Densities and Kinematic Viscosities for the Systems Benzene + Methyl Formate, Benzene + Ethyl Formate, Benzene + Propyl Formate, and Benzene + Butyl Formate

    DEFF Research Database (Denmark)

    Emmerling, Uwe; Rasmussen, Peter

    1998-01-01

    Densities and kinematic viscosities have been measured for the system benzene + methyl formate at 20°C and for the systems benzene + ethyl formate, benzene + propyl formate, and benzene + butyl formate from 20°C to 50°C. The results for the system benzene + methyl formate have been correlated usi...

  2. Protecting Critical Infrastructure by Identifying Pathways of Exposure to Risk

    Directory of Open Access Journals (Sweden)

    Philip O’Neill

    2013-08-01

    Full Text Available Increasingly, our critical infrastructure is managed and controlled by computers and the information networks that connect them. Cyber-terrorists and other malicious actors understand the economic and social impact that a successful attack on these systems could have. While it is imperative that we defend against such attacks, it is equally imperative that we realize how best to react to them. This article presents the strongest-path method of analyzing all potential pathways of exposure to risk – no matter how indirect or circuitous they may be – in a network model of infrastructure and operations. The method makes direct use of expert knowledge about entities and dependency relationships without the need for any simulation or any other models. By using path analysis in a directed graph model of critical infrastructure, planners can model and assess the effects of a potential attack and develop resilient responses.

  3. Benzene and toluene in the surface air of northern Eurasia from TROICA-12 campaign along the Trans-Siberian Railway

    Science.gov (United States)

    Skorokhod, Andrey I.; Berezina, Elena V.; Moiseenko, Konstantin B.; Elansky, Nikolay F.; Belikov, Igor B.

    2017-05-01

    Volatile organic compounds (VOCs) were measured by proton transfer reaction mass spectrometry (PTR-MS) on a mobile laboratory in a transcontinental TROICA-12 (21 July-4 August 2008) campaign along the Trans-Siberian Railway from Moscow to Vladivostok. Surface concentrations of benzene (C6H6) and toluene (C7H8) along with non-methane hydrocarbons (NMHCs), CO, O3, SO2, NO, NO2 and meteorology are analyzed in this study to identify the main sources of benzene and toluene along the Trans-Siberian Railway. The most measurements in the TROICA-12 campaign were conducted under low-wind/stagnant conditions in moderately ( ˜ 78 % of measurements) to weakly polluted ( ˜ 20 % of measurements) air directly affected by regional anthropogenic sources adjacent to the railway. Only 2 % of measurements were identified as characteristic of highly polluted urban atmosphere. Maximum values of benzene and toluene during the campaign reached 36.5 and 45.6 ppb, respectively, which is significantly less than their short-term exposure limits (94 and 159 ppb for benzene and toluene, respectively). About 90 % of benzene and 65 % of toluene content is attributed to motor vehicle transport and 10 and 20 %, respectively, provided by the other local- and regional-scale sources. The highest average concentrations of benzene and toluene are measured in the industrial regions of the European Russia (up to 0.3 and 0.4 ppb for benzene and toluene, respectively) and south Siberia (up to 0.2 and 0.4 ppb for benzene and toluene, respectively). Total contribution of benzene and toluene to photochemical ozone production along the Trans-Siberian Railway is about 16 % compared to the most abundant organic VOC - isoprene. This contribution, however, is found to be substantially higher (up to 60-70 %) in urbanized areas along the railway, suggesting an important role of anthropogenic pollutant sources in regional ozone photochemistry and air quality.

  4. Transcriptomics analysis of interactive effects of benzene, trichloroethylene and methyl mercury within binary and ternary mixtures on the liver and kidney following subchronic exposure in the rat

    NARCIS (Netherlands)

    Hendriksen, P.J.M.; Freidig, A.P.; Jonker, D.; Thissen, U.; Bogaards, J.J.P.; Mumtaz, M.M.; Groten, J.P.; Stierum, R.H.

    2007-01-01

    The present research aimed to study the interaction of three chemicals, methyl mercury, benzene and trichloroethylene, on mRNA expression alterations in rat liver and kidney measured by microarray analysis. These compounds were selected based on presumed different modes of action. The chemicals were

  5. The investigation of exposure to benzene, toluene, ethylbenzene and xylene (BTEX with Solid Phase Microextr action Method in gas station in Yazd province

    Directory of Open Access Journals (Sweden)

    Mohammad Hossein Mosaddegh Mehrjerdi

    2014-01-01

    Full Text Available Abstract Background: Benzene, toluene, ethylbenzene and xylene (BTEX are volatile organic compounds which their physical and chemical characteristics are similar. Evaporation of BTEX from gasoline in petrol station into the air causes gasoline station attendants expose to them. A new extraction method of volatile organic compounds is solid phase microextraction (SPME. The aim of this study is to optimize extraction conditions of BTEX from air samples and then determination of gasoline station air contamination with BTEX in Yazd. Material and Methods: In this study air samples were collected using Tedlar bags and then extracted and analyzed with SPME fiber and gas chromatography equipped with a flame ionization detector. Results: Our results indicate that PDMS/CAR has the best peak area in comparison with two other fibers The Optimized extraction and desorption times are estimated 3 and 1 minutes, respectively Mean concentration of benzene, toluene, ethyl benzene and xylene in gas station’s air were 1932±807, 667±405, 148±89, 340±216 µg/m3 respectively. Conclusion: Benzene mean concentration is above threshold limit value (0.5PPM. Whereas, toluene, ethylbenzene and xylene mean concentration are lower than threshold limit values.

  6. Benzene and its Isomers

    Indian Academy of Sciences (India)

    instantly brings benzene to mind. Benzene is one of the most basic structural units of thousands of the so-called aromatic compounds, which include dyes, drugs, polymers and many more types of compounds that are very useful for our existence and progress. The whole gamut of the chemistry of aromatic compounds, ...

  7. Benzene and its Isomers

    Indian Academy of Sciences (India)

    present vast knowledge of extremely complex structures of thou- sands of organic compounds, the structure of benzene now appears ridiculously simple, but it had taken nearly half a century of effort by some of the greatest ever scientists to arrive at it correctly. Benzene was discovered by Michael Faraday in the year 1825 ...

  8. Densities and Kinematic Viscosities for the Systems Benzene + Methyl Formate, Benzene + Ethyl Formate, Benzene + Propyl Formate, and Benzene + Butyl Formate

    DEFF Research Database (Denmark)

    Emmerling, Uwe; Rasmussen, Peter

    1998-01-01

    Densities and kinematic viscosities have been measured for the system benzene + methyl formate at 20°C and for the systems benzene + ethyl formate, benzene + propyl formate, and benzene + butyl formate from 20°C to 50°C. The results for the system benzene + methyl formate have been correlated using...... a Redlich-Kister type of expression with temperature-independent parameters and the data for the systems benzene + ethyl formate, benzene + propyl formate, and benzene + butyl formate with temperature-dependent parameters. The viscosities have furthermore been compared to values predicted by means of the GC...

  9. Are polymorphisms in metabolism protective or a risk for reduced white blood cell counts in a Chinese population with low occupational benzene exposures?

    Science.gov (United States)

    Ye, Ling-li; Zhang, Guang-hui; Huang, Jing-wen; Li, Yong; Zheng, Guo-qiao; Zhang, De-ting; Zhou, Li-fang; Tao, Xi-dan; Zhang, Jing; Ye, Yun-jie; Sun, Pin; Frank, Arthur; Xia, Zhao-lin

    2015-01-01

    Background: Genetic variations in metabolic enzyme genes may enhance hematotoxicity in benzene-exposed populations. Objective: To investigate the association between polymorphisms of metabolism genes and white blood cells (WBCs). Methods: Three hundred and eighty-five benzene-exposed workers and 220 unexposed indoor workers were recruited in China. We explored the relationship between metabolic enzymes polymorphisms [glutathione S-transferase T1/M1 (GSTT1/M1) null, glutathione S-transferase P1 (GSTP1)rs1695, Cytochrome P450 2E1 (CYP2E1) rs3813867, rs2031920, rs6413432, microsomal epoxide hydrolase (mEH) rs1051740, rs2234922] by polymerase chain reaction (PCR)–restriction fragment length polymorphism (RFLP) analysis and WBC. Results: The exposed group had lower WBC counts (Pbenzene-exposed workers in China, and we can make use of it to select susceptible population. PMID:26179485

  10. Perinatal bisphenol A exposure and adult glucose homeostasis: identifying critical windows of exposure.

    Directory of Open Access Journals (Sweden)

    Jingli Liu

    Full Text Available Bisphenol A (BPA is a widespread endocrine-disrupting chemical used as the building block for polycarbonate plastics. Epidemiological evidence has correlated BPA exposure with higher risk of heart disease and type 2 diabetes. However, it remains unknown whether there are critical windows of susceptibility to BPA exposure on the development of dysglycemia. This study was an attempt to investigate the critical windows and the long-term consequences of perinatal exposure to BPA on glucose homeostasis. Pregnant mice were given either vehicle or BPA (100 µg/kg/day at different time of perinatal stage: 1 on days 1-6 of pregnancy (P1-P6, preimplantation exposure; 2 from day 6 of pregnancy until postnatal day (PND 0 (P6-PND0, fetal exposure; 3 from lactation until weaning (PND0-PND21, neonatal exposure; and 4 from day 6 of gestation until weaning (P6-PND21, fetal and neonatal exposure. At 3, 6 and 8 months of age, offspring in each group were challenged with glucose and insulin tolerance tests. Then islet morphometry and β-cell function were measured. The glucose homeostasis was impaired in P6-PND0 mice from 3 to 6 months of age, and this continued to 8 months in males, but not females. While in PND0-PND21 and P6-PND21 BPA-treated groups, only the 3-month-old male offspring developed glucose intolerance. Moreover, at the age of 3 months, perinatal exposure to BPA resulted in the increase of β-cell mass mainly due to the coordinate changes in cell replication, neogenesis, and apoptosis. The alterations of insulin secretion and insulin sensitivity, rather than β-cell mass, were consistent with the development of glucose intolerance. Our findings suggest that BPA may contribute to metabolic disorders relevant to glucose homeostasis and the effects of BPA were dose, sex, and time-dependent. Fetal development stage may be the critical window of susceptibility to BPA exposure.

  11. Cytokine Network Involvement in Subjects Exposed to Benzene

    Science.gov (United States)

    Gangemi, Sebastiano

    2014-01-01

    Benzene represents an ubiquitous pollutant both in the workplace and in the general environment. Health risk and stress posed by benzene have long been a concern because of the carcinogenic effects of the compound which was classified as a Group 1 carcinogen to humans and animals. There is a close correlation between leukemia, especially acute myeloid leukemia, and benzene exposure. In addition, exposure to benzene can cause harmful effects on immunological, neurological, and reproductive systems. Benzene can directly damage hematopoietic progenitor cells, which in turn could lead to apoptosis or may decrease responsiveness to cytokines and cellular adhesion molecules. Alternatively, benzene toxicity to stromal cells or mature blood cells could disrupt the regulation of hematopoiesis, including hematopoietic commitment, maturation, or mobilization, through the network of cytokines, chemokines, and adhesion molecules. Today there is mounting evidence that benzene may alter the gene expression, production, or processing of several cytokines in vitro and in vivo. The purpose of this review was to systematically analyze the published cases of cytokine effects on human benzene exposure, particularly hematotoxicity, and atopy, and on lungs. PMID:25202711

  12. Benzene from Traffic

    DEFF Research Database (Denmark)

    Palmgren, F.; Berkowicz, R.; Skov, H.

    number of petrol vehicles with three way catalysts, 60-70% in 1999. The very steep decreasing trend for benzene at the beginning of the period from 1994 was explained by the combination of more catalyst vehicles and reduced benzene content in Danish petrol. The total amount of aromatics in petrol......, including toluene, increased only weakly. The analyses of air concentrations were confirmed by analyses of petrol sold in Denmark. The concentration of benzene at Jagtvej in Copenhagen is still in 1998 above the expected new EU limit value, 5 µg/m3 as annual average. However, the reduced content of benzene...... in petrol from 1998 and the increasing number of vehicles with catalysts will probably lead to compliance with this limit value...

  13. Benzene Monitor System report

    International Nuclear Information System (INIS)

    Livingston, R.R.

    1992-01-01

    Two systems for monitoring benzene in aqueous streams have been designed and assembled by the Savannah River Technology Center, Analytical Development Section (ADS). These systems were used at TNX to support sampling studies of the full-scale open-quotes SRAT/SME/PRclose quotes and to provide real-time measurements of benzene in Precipitate Hydrolysis Aqueous (PHA) simulant. This report describes the two ADS Benzene Monitor System (BMS) configurations, provides data on system operation, and reviews the results of scoping tests conducted at TNX. These scoping tests will allow comparison with other benzene measurement options being considered for use in the Defense Waste Processing Facility (DWPF) laboratory. A report detailing the preferred BMS configuration statistical performance during recent tests has been issued under separate title: Statistical Analyses of the At-line Benzene Monitor Study, SCS-ASG-92-066. The current BMS design, called the At-line Benzene Monitor (ALBM), allows remote measurement of benzene in PHA solutions. The authors have demonstrated the ability to calibrate and operate this system using peanut vials from a standard Hydragard trademark sampler. The equipment and materials used to construct the ALBM are similar to those already used in other applications by the DWPF lab. The precision of this system (±0.5% Relative Standard Deviation (RSD) at 1 sigma) is better than the purge ampersand trap-gas chromatograpy reference method currently in use. Both BMSs provide a direct measurement of the benzene that can be purged from a solution with no sample pretreatment. Each analysis requires about five minutes per sample, and the system operation requires no special skills or training. The analyzer's computer software can be tailored to provide desired outputs. Use of this system produces no waste stream other than the samples themselves (i.e. no organic extractants)

  14. Pesticide-exposure Matrix helps identify active ingredients in pesticides used in past years

    Science.gov (United States)

    Pesticide-exposure Matrix was developed to help epidemiologists and other researchers identify the active ingredients to which people were likely exposed when their homes and gardens were treated for pests in past years

  15. Investigation into Variation of Endogenous Metabolites in Bone Marrow Cells and Plasma in C3H/He Mice Exposed to Benzene

    Science.gov (United States)

    Sun, Rongli; Zhang, Juan; Yin, Lihong; Pu, Yuepu

    2014-01-01

    Benzene is identified as a carcinogen. Continued exposure of benzene may eventually lead to damage to the bone marrow, accompanied by pancytopenia, aplastic anemia or leukemia. This paper explores the variations of endogenous metabolites to provide possible clues for the molecular mechanism of benzene-induced hematotoxicity. Liquid chromatography coupled with time of flight-mass spectrometry (LC-TOF-MS) and principal component analysis (PCA) was applied to investigate the variation of endogenous metabolites in bone marrow cells and plasma of male C3H/He mice. The mice were injected subcutaneously with benzene (0, 300, 600 mg/day) once daily for seven days. The body weights, relative organ weights, blood parameters and bone marrow smears were also analyzed. The results indicated that benzene caused disturbances in the metabolism of oxidation of fatty acids and essential amino acids (lysine, phenylalanine and tyrosine) in bone marrow cells. Moreover, fatty acid oxidation was also disturbed in plasma and thus might be a common disturbed metabolic pathway induced by benzene in multiple organs. This study aims to investigate the underlying molecular mechanisms involved in benzene hematotoxicity, especially in bone marrow cells. PMID:24658442

  16. Validation of an online dual-loop cleanup device with an electrospray ionization tandem mass spectrometry-based system for simultaneous quantitative analysis of urinary benzene exposure biomarkers trans, trans-muconic acid and S-phenylmercapturic acid

    International Nuclear Information System (INIS)

    Lin, L.-C.; Chiung, Y.-M.; Shih, J.-F.; Shih, T.-S.G; Liao, P.-C.

    2006-01-01

    The aim of this study is to validate isotope-dilution electrospray ionization tandem mass spectrometry (ESI-MS-MS) method with a dual-loop cleanup device for simultaneous quantitation of two benzene metabolites, trans, trans-muconic acid (ttMA) and S-phenylmercapturic acid (SPMA), in human urine. In this study, a pooled blank urine matrix from rural residents was adopted for validation of the analytical method. The calibration curve, detection limit, recovery, precision, accuracy and the stability of sample storage for the system have been characterized. Calibration plots of ttMA and SPMA standards spiked into two kinds of urine matrixes over a wide concentration range, 1/32-8-fold biological exposure indices (BEIs) values, showed good linearity (R > 0.9992). The detection limits in pooled urine matrix for ttMA and SPMA were 1.27 and 0.042 μg g -1 creatinine, respectively. For both of ttMA and SPMA, the intra- and inter-day precision values were considered acceptable well below 25% at the various spiked concentrations. The intra- and inter-day apparent recovery values were also considered acceptable (apparent recovery >90%). The ttMA accuracy was estimated by urinary standard reference material (SRM). The accuracy reported in terms of relative error (RE) was 5.0 ± 2.0% (n = 3). The stability of sample storage at 4 or -20 deg. C were assessed. Urinary ttMA and SPMA were found to be stable for at least 8 weeks when stored at 4 or -20 deg. C. In addition, urine samples from different benzene exposure groups were collected and measured in this system. Without tedious manual sample preparation procedure, the analytical system was able to quantify simultaneously ttMA and SPMA in less than 20 min

  17. Comparative metabolism of [14C]benzene to excretable products and bioactivation to DNA-binding derivatives in maternal and neonatal mice

    International Nuclear Information System (INIS)

    Iba, M.M.; Ghosal, A.; Snyder, R.

    2001-01-01

    Lactating adult female mice treated with a single dose of 880 mg/kg i.p. [ 14 C]benzene, and their 2-day-old sucklings similarly treated or nursed by their treated dams were compared in terms of their ability to metabolize benzene to urinary products or reactive intermediates as assessed by covalently-bound benzene derivatives in whole blood or liver DNA. Six metabolite fractions were identified in the urine of sucklings by high performance liquid chromatographic (HPLC) analysis at 5 h following intraperitoneal (direct) treatment with benzene. Three of the metabolite fractions co-chromatographed with authentic phenol, phenyl glucuronide, and muconic acid, and contributed 11, 6.9 and 0.6%, respectively, to the total urinary benzene metabolites. Two of the fractions were unidentified. The sixth and most polar fraction consisted of multiple metabolites, 21% of which were conjugates, and accounted for 72% of the total urinary metabolites. A similar metabolite profile was observed in 24-h urine samples from treated dams with the exception that one of the unidentified fractions in the sucklings was absent and levels of the metabolites were quantitatively higher than those observed in sucklings 5 h following their treatment with benzene. Furthermore, 78% of the most polar fraction from the dams consisted of conjugates compared with 21% of that from the sucklings. The metabolite pattern in urine of sucklings nursed by treated dams was qualitatively similar to, but quantitatively different from the pattern in treated dams. Five hours following intraperitoneal treatment with benzene, covalent binding of the compound to DNA (expressed as pmol benzene equivalents/mg DNA) in sucklings was slightly higher in whole blood (1.15±0.07) than in liver (0.77±0.07), whereas in the dam, it was slightly lower in whole blood (0.88±0.48) than in liver (1.63±0.61). Twenty four hours following benzene exposure in sucklings of benzene-treated dams, DNA binding by the compound in whole

  18. Non-parametric estimation of low-concentration benzene metabolism.

    Science.gov (United States)

    Cox, Louis A; Schnatter, A Robert; Boogaard, Peter J; Banton, Marcy; Ketelslegers, Hans B

    2017-12-25

    Two apparently contradictory findings in the literature on low-dose human metabolism of benzene are as follows. First, metabolism is approximately linear at low concentrations, e.g., below 10 ppm. This is consistent with decades of quantitative modeling of benzene pharmacokinetics and dose-dependent metabolism. Second, measured benzene exposure and metabolite concentrations for occupationally exposed benzene workers in Tianjin, China show that dose-specific metabolism (DSM) ratios of metabolite concentrations per ppm of benzene in air decrease steadily with benzene concentration, with the steepest decreases below 3 ppm. This has been interpreted as indicating that metabolism at low concentrations of benzene is highly nonlinear. We reexamine the data using non-parametric methods. Our main conclusion is that both findings are correct; they are not contradictory. Low-concentration metabolism can be linear, with metabolite concentrations proportional to benzene concentrations in air, and yet DSM ratios can still decrease with benzene concentrations. This is because a ratio of random variables can be negatively correlated with its own denominator even if the mean of the numerator is proportional to the denominator. Interpreting DSM ratios that decrease with air benzene concentrations as evidence of nonlinear metabolism is therefore unwarranted when plots of metabolite concentrations against benzene ppm in air show approximately straight-line relationships between them, as in the Tianjin data. Thus, an apparent contradiction that has fueled heated discussions in the recent literature can be resolved by recognizing that highly nonlinear, decreasing DSM ratios are consistent with linear metabolism. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  19. Anaerobic benzene degradation by bacteria

    OpenAIRE

    Vogt, Carsten; Kleinsteuber, Sabine; Richnow, Hans‐Hermann

    2011-01-01

    Summary Benzene is a widespread and toxic contaminant. The fate of benzene in contaminated aquifers seems to be primarily controlled by the abundance of oxygen: benzene is aerobically degraded at high rates by ubiquitous microorganisms, and the oxygen‐dependent pathways for its breakdown were elucidated more than 50 years ago. In contrast, benzene was thought to be persistent under anoxic conditions until 25 years ago. Nevertheless, within the last 15 years, several benzene‐degrading cultures...

  20. Influence of Type and Amount of Carbon in Cigarette Filters on Smokers’ Mouth Level Exposure to “Tar”, Nicotine, 1,3-Butadiene, Benzene, Toluene, Isoprene, and Acrylonitrile

    Directory of Open Access Journals (Sweden)

    Nother Kathryn

    2016-04-01

    Full Text Available Activated carbons are effective adsorbents for many volatile organic compounds and are used in cigarette filters to remove selected smoke toxicants. Polymer-derived carbon is more effective in removing many vapour phase toxicants found in cigarette smoke than coconut-shell-derived carbon. We compared mouth-level exposure to “tar”, nicotine and five vapour phase constituents (1,3- butadiene, benzene, toluene, isoprene, acrylonitrile in two groups of Romanian smokers of 4-mg or 8-mg International Organization for Standardization (ISO “tar” bands. Test cigarettes with 4 and 8 mg ISO “tar” were manufactured for the study with two target levels of polymer-derived carbon (30 mg and 56 mg, along with control cigarettes containing a target level of 56 mg of coconut-shell-derived carbon in both “tar” bands. No significant differences were found between mouth-level exposure to “tar” or nicotine yields obtained from control and test products (p > 0.05 in either ISO “tar” band. Mouth-level exposure to each of the five vapour phase constituents was significantly lower from the test products with polymer-derived carbon (p < 0.0001 than from control cigarettes with coconut-shell-derived carbon, by an average of 25% with 30 mg polymer-derived carbon and around 50% with 56 mg. [Beitr. Tabakforsch. Int. 27 (2016 40-53

  1. Lagged kernel machine regression for identifying time windows of susceptibility to exposures of complex mixtures.

    Science.gov (United States)

    Liu, Shelley H; Bobb, Jennifer F; Lee, Kyu Ha; Gennings, Chris; Claus Henn, Birgit; Bellinger, David; Austin, Christine; Schnaas, Lourdes; Tellez-Rojo, Martha M; Hu, Howard; Wright, Robert O; Arora, Manish; Coull, Brent A

    2017-09-06

    The impact of neurotoxic chemical mixtures on children's health is a critical public health concern. It is well known that during early life, toxic exposures may impact cognitive function during critical time intervals of increased vulnerability, known as windows of susceptibility. Knowledge on time windows of susceptibility can help inform treatment and prevention strategies, as chemical mixtures may affect a developmental process that is operating at a specific life phase. There are several statistical challenges in estimating the health effects of time-varying exposures to multi-pollutant mixtures, such as: multi-collinearity among the exposures both within time points and across time points, and complex exposure-response relationships. To address these concerns, we develop a flexible statistical method, called lagged kernel machine regression (LKMR). LKMR identifies critical exposure windows of chemical mixtures, and accounts for complex non-linear and non-additive effects of the mixture at any given exposure window. Specifically, LKMR estimates how the effects of a mixture of exposures change with the exposure time window using a Bayesian formulation of a grouped, fused lasso penalty within a kernel machine regression (KMR) framework. A simulation study demonstrates the performance of LKMR under realistic exposure-response scenarios, and demonstrates large gains over approaches that consider each time window separately, particularly when serial correlation among the time-varying exposures is high. Furthermore, LKMR demonstrates gains over another approach that inputs all time-specific chemical concentrations together into a single KMR. We apply LKMR to estimate associations between neurodevelopment and metal mixtures in Early Life Exposures in Mexico and Neurotoxicology, a prospective cohort study of child health in Mexico City. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. Subtoxic and toxic concentrations of benzene and toluene induce Nrf2-mediated antioxidative stress response and affect the central carbon metabolism in lung epithelial cells A549.

    Science.gov (United States)

    Murugesan, Kalaimathi; Baumann, Sven; Wissenbach, Dirk K; Kliemt, Stefanie; Kalkhof, Stefan; Otto, Wolfgang; Mögel, Iljana; Kohajda, Tibor; von Bergen, Martin; Tomm, Janina M

    2013-11-01

    Since people in industrialized countries spend most of their time indoors, the effects of indoor contaminants such as volatile organic compounds become more and more relevant. Benzene and toluene are among the most abundant compounds in the highly heterogeneous group of indoor volatile organic compounds. In order to understand their effects on lung epithelial cells (A549) representing lung's first line of defense, we chose a global proteome and a targeted metabolome approach in order to detect adverse outcome pathways caused by exposure to benzene and toluene. Using a DIGE approach, 93 of 469 detected protein spots were found to be differentially expressed after exposure to benzene, and 79 of these spots were identified by MS. Pathway analysis revealed an enrichment of proteins involved in Nrf2-mediated and oxidative stress response glycolysis/gluconeogenesis. The occurrence of oxidative stress at nonacute toxic concentrations of benzene and toluene was confirmed by the upregulation of the stress related proteins NQO1 and SOD1. The changes in metabolism were validated by ion chromatography MS/MS analysis revealing significant changes of glucose-6-phosphate, fructose-6-phosphate, 3-phosphoglycerate, and NADPH. The molecular alterations identified as a result of benzene and toluene exposure demonstrate the detrimental effect of nonacute toxic concentrations on lung epithelial cells. The data provided here will allow for a targeted validation in in vivo models. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Benzene and its Isomers

    Indian Academy of Sciences (India)

    part of an assignment given by a gas company. The gas obtained by thermal decomposition of whale oil used to be stored in cylinders under pressure for illuminating streetlights. Faraday succeeded in isolating benzene by distillation and crystalliza- tion of the light mobile oil left behind in the gas cylinders. He was also able ...

  4. Benzene and its Isomers

    Indian Academy of Sciences (India)

    Benzene and its Isomers atomic weights and availability of improved analytical methods. At this time the .... geometry. Forcing them in cyclic structures would lead to signifi- cant strain. Bicyclic structures do not easily accommodate double bonds at bridgehead positions (Bredt's rule). Many of the polycy- clic isomers clearly ...

  5. On Benzene and Aromaticity

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 4. On Benzene and Aromaticity History and Some Folklore. M V Bhatt. General Article Volume 3 Issue 4 April 1998 pp 88-93. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/003/04/0088-0093 ...

  6. Benzene and its Isomers

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 6; Issue 5. Benzene and its Isomers - How many Structures can we Draw for C6H6? Gopalpur Nagendrappa. General Article Volume 6 Issue 5 May 2001 pp 74-78. Fulltext. Click here to view fulltext PDF. Permanent link:

  7. Benzene as a Chemical Hazard in Processed Foods

    Directory of Open Access Journals (Sweden)

    Vânia Paula Salviano dos Santos

    2015-01-01

    Full Text Available This paper presents a literature review on benzene in foods, including toxicological aspects, occurrence, formation mechanisms, and mitigation measures and analyzes data reporting benzene levels in foods. Benzene is recognized by the IARC (International Agency for Research on Cancer as carcinogenic to humans, and its presence in foods has been attributed to various potential sources: packaging, storage environment, contaminated drinking water, cooking processes, irradiation processes, and degradation of food preservatives such as benzoates. Since there are no specific limits for benzene levels in beverages and food in general studies have adopted references for drinking water in a range from 1–10 ppb. The presence of benzene has been reported in various food/beverage substances with soft drinks often reported in the literature. Although the analyses reported low levels of benzene in most of the samples studied, some exceeded permissible limits. The available data on dietary exposure to benzene is minimal from the viewpoint of public health. Often benzene levels were low as to be considered negligible and not a consumer health risk, but there is still a need of more studies for a better understanding of their effects on human health through the ingestion of contaminated food.

  8. 40 CFR 721.1240 - Benzene, (2-bromoethyl)-, ar-bromo derivatives.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzene, (2-bromoethyl)-, ar-bromo... Specific Chemical Substances § 721.1240 Benzene, (2-bromoethyl)-, ar-bromo derivatives. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as benzene...

  9. 40 CFR 721.9595 - Alkyl benzene sulfonic acids and alkyl sulfates, amine salts (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkyl benzene sulfonic acids and alkyl... Significant New Uses for Specific Chemical Substances § 721.9595 Alkyl benzene sulfonic acids and alkyl...) The chemical substances identified generically as alkyl benzene sulfonic acids and alkyl sulfates...

  10. 40 CFR 721.1230 - Benzene, ethenyl-, ar-bromo derivatives.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzene, ethenyl-, ar-bromo... Specific Chemical Substances § 721.1230 Benzene, ethenyl-, ar-bromo derivatives. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as benzene, ethenyl-, ar...

  11. 40 CFR 721.10096 - Benzene, 1,4-bis (methoxymethyl)-.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzene, 1,4-bis (methoxymethyl)-. 721... Substances § 721.10096 Benzene, 1,4-bis (methoxymethyl)-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as benzene, 1,4-bis (methoxymethyl)- (PMN P-03...

  12. 40 CFR 721.1325 - Benzene, 1-(1-methyl-bu-toxy)-4-nitro-.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzene, 1-(1-methyl-bu-toxy)-4-nitro... Substances § 721.1325 Benzene, 1-(1-methyl-bu-toxy)-4-nitro-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as benzene, 1-(1-methylbutoxy)-4-nitro- (PMN P...

  13. 40 CFR 721.1193 - Benzene, 2-bromo-1,4-dimethoxy-.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzene, 2-bromo-1,4-dimethoxy-. 721... Substances § 721.1193 Benzene, 2-bromo-1,4-dimethoxy-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as benzene, 2-bromo-1,4-dimethoxy- (PMN P-95...

  14. Current understandings and perspectives on non-cancer health effects of benzene: A global concern

    International Nuclear Information System (INIS)

    Bahadar, Haji; Mostafalou, Sara; Abdollahi, Mohammad

    2014-01-01

    Objective: Benzene, as a volatile organic compound, is known as one of the main air pollutants in the environment. The aim of this review is to summarize all available evidences on non-cancerous health effects of benzene providing an overview of possible association of exposure to benzene with human chronic diseases, specially, in those regions of the world where benzene concentration is being poorly monitored. Methodology: A bibliographic search of scientific databases including PubMed, Google Scholar, and Scirus was conducted with key words of “benzene toxic health effects”, “environmental volatile organic compounds”, “diabetes mellitus and environmental pollutants”, “breast cancer and environmental pollution”, “prevalence of lung cancer”, and “diabetes prevalence”. More than 300 peer reviewed papers were examined. Experimental and epidemiologic studies reporting health effects of benzene and volatile organic compounds were included in the study. Results: Epidemiologic and experimental studies suggest that benzene exposure can lead to numerous non-cancerous health effects associated with functional aberration of vital systems in the body like reproductive, immune, nervous, endocrine, cardiovascular, and respiratory. Conclusion: Chronic diseases have become a health burden of global dimension with special emphasis in regions with poor monitoring over contents of benzene in petrochemicals. Benzene is a well known carcinogen of blood and its components, but the concern of benzene exposure is more than carcinogenicity of blood components and should be evaluated in both epidemiologic and experimental studies. Aspect of interactions and mechanism of toxicity in relation to human general health problems especially endocrine disturbances with particular reference to diabetes, breast and lung cancers should be followed up. - Highlights: • Benzene is a volatile organic compound and established blood carcinogen. • Exposure to benzene needs to be

  15. Current understandings and perspectives on non-cancer health effects of benzene: A global concern

    Energy Technology Data Exchange (ETDEWEB)

    Bahadar, Haji [International Campus, Tehran University of Medical Sciences (Iran, Islamic Republic of); Pharmaceutical Sciences Research Center and Faculty of Pharmacy, Tehran University of Medical Sciences (Iran, Islamic Republic of); Mostafalou, Sara [Pharmaceutical Sciences Research Center and Faculty of Pharmacy, Tehran University of Medical Sciences (Iran, Islamic Republic of); Abdollahi, Mohammad, E-mail: Mohammad.Abdollahi@UToronto.Ca [Pharmaceutical Sciences Research Center and Faculty of Pharmacy, Tehran University of Medical Sciences (Iran, Islamic Republic of)

    2014-04-15

    Objective: Benzene, as a volatile organic compound, is known as one of the main air pollutants in the environment. The aim of this review is to summarize all available evidences on non-cancerous health effects of benzene providing an overview of possible association of exposure to benzene with human chronic diseases, specially, in those regions of the world where benzene concentration is being poorly monitored. Methodology: A bibliographic search of scientific databases including PubMed, Google Scholar, and Scirus was conducted with key words of “benzene toxic health effects”, “environmental volatile organic compounds”, “diabetes mellitus and environmental pollutants”, “breast cancer and environmental pollution”, “prevalence of lung cancer”, and “diabetes prevalence”. More than 300 peer reviewed papers were examined. Experimental and epidemiologic studies reporting health effects of benzene and volatile organic compounds were included in the study. Results: Epidemiologic and experimental studies suggest that benzene exposure can lead to numerous non-cancerous health effects associated with functional aberration of vital systems in the body like reproductive, immune, nervous, endocrine, cardiovascular, and respiratory. Conclusion: Chronic diseases have become a health burden of global dimension with special emphasis in regions with poor monitoring over contents of benzene in petrochemicals. Benzene is a well known carcinogen of blood and its components, but the concern of benzene exposure is more than carcinogenicity of blood components and should be evaluated in both epidemiologic and experimental studies. Aspect of interactions and mechanism of toxicity in relation to human general health problems especially endocrine disturbances with particular reference to diabetes, breast and lung cancers should be followed up. - Highlights: • Benzene is a volatile organic compound and established blood carcinogen. • Exposure to benzene needs to be

  16. Investigation of Occupational Asthma: Do Clinicians Fail to Identify rRelevant Occupational Exposures?

    Directory of Open Access Journals (Sweden)

    Carlo de Olim

    2015-01-01

    Full Text Available BACKGROUND: Specific inhalation challenges (SIC enable the identification of the agent responsible of occupational asthma (OA. A clinician may fail to identify a specific agent in the workplace, which may potentially lead to a misdiagnosis. The expert assessment method performed by an occupational hygienist has been used to evaluate occupational exposures in epidemiological studies.

  17. Early Liver and Kidney Dysfunction Associated with Occupational Exposure to Sub-Threshold Limit Value Levels of Benzene, Toluene, and Xylenes in Unleaded Petrol

    Directory of Open Access Journals (Sweden)

    Masoud Neghab

    2015-12-01

    Conclusion: The average exposure of petrol station workers to BTX did not exceed the current threshold limit values (TLVs for these chemicals. However, evidence of subtle, subclinical and prepathologic early liver and kidney dysfunction was evident in exposed individuals.

  18. Metagenomic and proteomic analyses to elucidate the mechanism of anaerobic benzene degradation

    Energy Technology Data Exchange (ETDEWEB)

    Abu Laban, Nidal [Helmholtz (Germany)

    2011-07-01

    This paper presents the mechanism of anaerobic benzene degradation using metagenomic and proteomic analyses. The objective of the study is to find out the microbes and biochemistry involved in benzene degradation. Hypotheses are proposed for the initial activation mechanism of benzene under anaerobic conditions. Two methods for degradation, molecular characterization and identification of benzene-degrading enzymes, are described. The physiological and molecular characteristics of iron-reducing enrichment culture are given and the process is detailed. Metagenome analysis of iron-reducing culture is presented using a pie chart. From the metagenome analysis of benzene-degrading culture, putative mobile element genes were identified in the aromatic-degrading configurations. Metaproteomic analysis of iron-reducing cultures and the anaerobic benzene degradation pathway are also elucidated. From the study, it can be concluded that gram-positive bacteria are involved in benzene degradation under iron-reducing conditions and that the catalysis mechanism of putative anaerobic benzene carboxylase needs further investigation.

  19. Surveillance of Washington OSHA exposure data to identify uncharacterized or emerging occupational health hazards.

    Science.gov (United States)

    Lofgren, Don J; Reeb-Whitaker, Carolyn K; Adams, Darrin

    2010-07-01

    Chemical substance exposure data from the Washington State Occupational Safety and Health Administration (OSHA) program were reviewed to determine if inspections conducted as a result of a report of a hazard from a complainant or referent may alert the agency to uncharacterized or emerging health hazards. Exposure and other electronically stored data from 6890 health inspection reports conducted between April 2003 and August 2008 were extracted from agency records. A total of 515 (7%) inspections with one or more personal airborne chemical substance samples were identified for further study. Inspections by report of a hazard and by targeting were compared for the following: number of inspections, number and percentage of inspections with workers exposed to substances above an agency's permissible exposure limit, types of industries inspected, and number and type of chemical substances assessed. Report of a hazard inspections documented work sites with worker overexposure at the same rate as agency targeted inspections (approximately 35% of the time), suggesting that complainants and referents are a credible pool of observers capable of directing the agency to airborne chemical substance hazards. Report of a hazard inspections were associated with significantly broader distribution of industries as well as a greater variety of chemical substance exposures than were targeted inspections. Narrative text that described business type and processes inspected was more useful than NAICS codes alone and critical in identifying processes and industries that may be associated with new hazards. Finally, previously identified emerging hazards were found among the report of a hazard data. These findings indicate that surveillance of OSHA inspection data can be a valid tool to identify uncharacterized and emerging health hazards. Additional research is needed to develop criteria for objective review and prioritization of the data for intervention. Federal OSHA and other state

  20. AN INTEGRATED NETWORK APPROACH TO IDENTIFYING BIOLOGICAL PATHWAYS AND ENVIRONMENTAL EXPOSURE INTERACTIONS IN COMPLEX DISEASES.

    Science.gov (United States)

    Darabos, Christian; Qiu, Jingya; Moore, Jason H

    2016-01-01

    Complex diseases are the result of intricate interactions between genetic, epigenetic and environmental factors. In previous studies, we used epidemiological and genetic data linking environmental exposure or genetic variants to phenotypic disease to construct Human Phenotype Networks and separately analyze the effects of both environment and genetic factors on disease interactions. To better capture the intricacies of the interactions between environmental exposure and the biological pathways in complex disorders, we integrate both aspects into a single "tripartite" network. Despite extensive research, the mechanisms by which chemical agents disrupt biological pathways are still poorly understood. In this study, we use our integrated network model to identify specific biological pathway candidates possibly disrupted by environmental agents. We conjecture that a higher number of co-occurrences between an environmental substance and biological pathway pair can be associated with a higher likelihood that the substance is involved in disrupting that pathway. We validate our model by demonstrating its ability to detect known arsenic and signal transduction pathway interactions and speculate on candidate cell-cell junction organization pathways disrupted by cadmium. The validation was supported by distinct publications of cell biology and genetic studies that associated environmental exposure to pathway disruption. The integrated network approach is a novel method for detecting the biological effects of environmental exposures. A better understanding of the molecular processes associated with specific environmental exposures will help in developing targeted molecular therapies for patients who have been exposed to the toxicity of environmental chemicals.

  1. Identifying the sources of greatest radiation exposure to NMT's during PET scanning

    International Nuclear Information System (INIS)

    Norton, Sarah; Cowell, Simon F.; Mi, Tian; Every, Bruce Van

    2009-01-01

    Full text: Introduction: The higher penetrating ability of 511 kev photons emitted by PET radionuclides combined with the long duration of the studies raises concern that NMTs receive higher radiation exposure levels while working with PET patients. Previous studies found the greatest exposure occurred while injecting the patient. This study aimed to determine the stage in the PET study with the highest radiation exposure to a NMT. Method: A Polimaster PM 1604A personal dosimeter was worn by one of the researchers whilst working alongside a NMT. 20 PET procedures were monitored over a four-day period. The average administered activity of F18-FDG was 332 MBq. Stages identified for measurement included: observing patient injection, escorting the patient to the toilet, setting-up the patient for the scan and escorting them to the change room. The time spent and the cumulative equivalent dose (CED) at each stage were recorded for each patient. Results: easurement Stage vg Time(min) vg CED(uSv), Observing patient injection .8 .26, Escorting patient to toilet .2 .39, Setting patient up for scan .0 .93, escorting patient to change room .8 .42. Total for all stages 1.8 .00. Discussion: This study found that 65% of a NMTs radiation exposure from a PET procedure occurred during scan setup, in proportion to their time spent with the patient. Strategies need to be implemented in PET departments to help minimise the exposure to MTs during each stage of a PET study.

  2. Benzene oxidation coupled to sulfate reduction

    Science.gov (United States)

    Lovley, D.R.; Coates, J.D.; Woodward, J.C.; Phillips, E.J.P.

    1995-01-01

    Highly reduced sediments from San Diego Bay, Calif., that were incubated under strictly anaerobic conditions metabolized benzene within 55 days when they were exposed initially to I ??M benzene. The rate of benzene metabolism increased as benzene was added back to the benzene-adapted sediments. When a [14C]benzene tracer was included with the benzene added to benzene-adapted sediments, 92% of the added radioactivity was recovered as 14CO2. Molybdate, an inhibitor of sulfate reduction, inhibited benzene uptake and production of 14CO2 from [14C]benzene. Benzene metabolism stopped when the sediments became sulfate depleted, and benzene uptake resumed when sulfate was added again. The stoichiometry of benzene uptake and sulfate reduction was consistent with the hypothesis that sulfate was the principal electron acceptor for benzene oxidation. Isotope trapping experiments performed with [14C]benzene revealed that there was no production of such potential extracellular intermediates of benzene oxidation as phenol, benzoate, p-hydroxybenzoate, cyclohexane, catechol, and acetate. The results demonstrate that benzene can be oxidized in the absence of O2, with sulfate serving as the electron acceptor, and suggest that some sulfate reducers are capable of completely oxidizing benzene to carbon dioxide without the production of extracellular intermediates. Although anaerobic benzene oxidation coupled to chelated Fe(III) has been documented previously, the study reported here provides the first example of a natural sediment compound that can serve as an electron acceptor for anaerobic benzene oxidation.

  3. Accumulation of chlorinated benzenes in earthworms

    Energy Technology Data Exchange (ETDEWEB)

    Beyer, W.N. [Patuxent Wildlife Research Center, Laurel, MD (United States)

    1996-12-31

    Chlorinated benzenes are widespread in the environment. Hexachlorobenzene, pentachlorobenzene and all isomers of dichlorobenzenes, trichlorobenzenes, and tetrachlorobenzenes, have been detected in fish, water, and sediments from the Great Lakes. They probably entered the water as leachates from chemical waste dumps and as effluents from manufacturing. Hexachlorobenzene and pentachlorobenzene are commonly present in Herring gull (Larus argentatus) eggs from the Great Lakes, and some of the isomers of trichlorobenzene and tetrachlorobenzene are occasionally detected at low concentrations. Hexachlorobenzene, which was formerly used as a fungicide, has been the most thoroughly studied chlorinated benzene, and has been detected in many species. Its use as a fungicide in the United States was canceled in 1984. Since about 1975 hexachlorobenzene has been formed mainly in the production of chlorinated solvents. It is highly persistent in the environment and some species are poisoned by hexachlorobenzene at very low chronic dietary exposures. As little as 1 ppm in the diet of mink (Mustela vison) reduced the birth weights of young, and 5 ppm in the diet of Japanese quail (Coturnix coturnix japonica) caused slight liver damage. This paper describes a long-term (26 wk) experiment relating the concentrations of chlorinated benzenes in earthworms to length of exposure and three 8 wk experiments relating concentration to the concentration in soil the soil organic matter content, and the degree of chlorination. 20 refs., 3 figs., 1 tab.

  4. [Myelofibrosis in a benzene-exposed cleaning worker].

    Science.gov (United States)

    Bausà, Roser; Navarro, Lydia; Cortès-Franch, Imma

    Long-term exposure to benzene has been associated with several blood malignancies, including aplastic anemia, myeloproliferative neoplasms, and different leukemias. We present a case of primary myelofibrosis in a 59-year-old woman who worked as a cleaner at a car dealership and automobile mechanic shop. For 25 years, she used gasoline as a degreaser and solvent to clean engine parts, floors and work desks on a daily basis. She was referred by her primary care provider to the Occupational Health Unit of Barcelona to assess whether her illness was work-related. Review of her job history and working conditions revealed chronic exposure to benzene in the absence of adequate preventive measures. An association between benzene exposure and myeloproliferative disease was established, suspicious for an occupational disease. Copyright belongs to the Societat Catalana de Salut Laboral.

  5. Assessing benzene-induced toxicity on wild type Euglena gracilis Z and its mutant strain SMZ.

    Science.gov (United States)

    Peng, Cheng; Arthur, Dionne M; Sichani, Homa Teimouri; Xia, Qing; Ng, Jack C

    2013-11-01

    Benzene is a representative member of volatile organic compounds and has been widely used as an industrial solvent. Groundwater contamination of benzene may pose risks to human health and ecosystems. Detection of benzene in the groundwater using chemical analysis is expensive and time consuming. In addition, biological responses to environmental exposures are uninformative using such analysis. Therefore, the aim of this study was to employ a microorganism, Euglena gracilis (E. gracilis) as a putative model to monitor the contamination of benzene in groundwater. To this end, we examined the wild type of E. gracilis Z and its mutant form, SMZ in their growth rate, morphology, chlorophyll content, formation of reactive oxygen species (ROS) and DNA damage in response to benzene exposure. The results showed that benzene inhibited cell growth in a dose response manner up to 48 h of exposure. SMZ showed a greater sensitivity compared to Z in response to benzene exposure. The difference was more evident at lower concentrations of benzene (0.005-5 μM) where growth inhibition occurred in SMZ but not in Z cells. We found that benzene induced morphological changes, formation of lipofuscin, and decreased chlorophyll content in Z strain in a dose response manner. No significant differences were found between the two strains in ROS formation and DNA damage by benzene at concentrations affecting cell growth. Based on these results, we conclude that E. gracilis cells were sensitive to benzene-induced toxicities for certain endpoints such as cell growth rate, morphological change, depletion of chlorophyll. Therefore, it is a potentially suitable model for monitoring the contamination of benzene and its effects in the groundwater. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Large-scale neurochemical metabolomics analysis identifies multiple compounds associated with methamphetamine exposure.

    Science.gov (United States)

    McClay, Joseph L; Adkins, Daniel E; Vunck, Sarah A; Batman, Angela M; Vann, Robert E; Clark, Shaunna L; Beardsley, Patrick M; van den Oord, Edwin J C G

    2013-04-01

    Methamphetamine (MA) is an illegal stimulant drug of abuse with serious negative health consequences. The neurochemical effects of MA have been partially characterized, with a traditional focus on classical neurotransmitter systems. However, these directions have not yet led to novel drug treatments for MA abuse or toxicity. As an alternative approach, we describe here the first application of metabolomics to investigate the neurochemical consequences of MA exposure in the rodent brain. We examined single exposures at 3 mg/kg and repeated exposures at 3 mg/kg over 5 days in eight common inbred mouse strains. Brain tissue samples were assayed using high-throughput gas and liquid chromatography mass spectrometry, yielding quantitative data on >300 unique metabolites. Association testing and false discovery rate control yielded several metabolome-wide significant associations with acute MA exposure, including compounds such as lactate ( p = 4.4 × 10 -5 , q = 0.013), tryptophan ( p = 7.0 × 10 -4 , q = 0.035) and 2-hydroxyglutarate ( p = 1.1 × 10 -4 , q = 0.022). Secondary analyses of MA-induced increase in locomotor activity showed associations with energy metabolites such as succinate ( p = 3.8 × 10 -7 ). Associations specific to repeated (5 day) MA exposure included phosphocholine ( p = 4.0 × 10 -4 , q = 0.087) and ergothioneine ( p = 3.0 × 10 -4 , q = 0.087). Our data appear to confirm and extend existing models of MA action in the brain, whereby an initial increase in energy metabolism, coupled with an increase in behavioral locomotion, gives way to disruption of mitochondria and phospholipid pathways and increased endogenous antioxidant response. Our study demonstrates the power of comprehensive MS-based metabolomics to identify drug-induced changes to brain metabolism and to develop neurochemical models of drug effects.

  7. Substituent Effect in Benzene Dication

    NARCIS (Netherlands)

    Palusiak, M.; Domagala, M.; Dominikowska, J.E.; Bickelhaupt, F.M.

    2014-01-01

    It was recently postulated that the benzene ring and its 4n + 2 π-electron analogues are resistant to the substituent effect due to the fact that such systems tend to retain their delocalized character. Therefore, the 4n π-electron dicationic form of benzene should appear to be less resistant to the

  8. Benzene Oxidation Coupled to Sulfate Reduction

    OpenAIRE

    Lovley, D. R.; Coates, J. D.; Woodward, J. C.; Phillips, E.

    1995-01-01

    Highly reduced sediments from San Diego Bay, Calif., that were incubated under strictly anaerobic conditions metabolized benzene within 55 days when they were exposed initially to 1 (mu)M benzene. The rate of benzene metabolism increased as benzene was added back to the benzene-adapted sediments. When a [(sup14)C]benzene tracer was included with the benzene added to benzene-adapted sediments, 92% of the added radioactivity was recovered as (sup14)CO(inf2). Molybdate, an inhibitor of sulfate r...

  9. Environmental and biological monitoring of benzene during self-service automobile refueling.

    Science.gov (United States)

    Egeghy, P P; Tornero-Velez, R; Rappaport, S M

    2000-12-01

    Although automobile refueling represents the major source of benzene exposure among the nonsmoking public, few data are available regarding such exposures and the associated uptake of benzene. We repeatedly measured benzene exposure and uptake (via benzene in exhaled breath) among 39 self-service customers using self-administered monitoring, a technique rarely used to obtain measurements from the general public (130 sets of measurements were obtained). Benzene exposures averaged 2.9 mg/m(3) (SD = 5.8 mg/m(3); median duration = 3 min) with a range of values falling within a 274-fold range, and was comprised entirely of the within-person component of variance (representing exposures of the same subject at different times of refueling). The corresponding range for benzene concentrations in breath was 41-fold and was comprised primarily of the within-person variance component (74% of the total variance). Our results indicate that environmental rather than interindividual differences are primarily responsible for benzene exposure and uptake during automobile refueling. The study also demonstrates that self-administered monitoring can be efficiently used to measure environmental exposures and biomarkers among the general public.

  10. Identifying With a Stereotype: The Divergent Effects of Exposure to Homosexual Television Characters.

    Science.gov (United States)

    McLaughlin, Bryan; Rodriguez, Nathian S

    2017-01-01

    Scholars examining homosexual television characters have typically come to one of two conclusions: either exposure to homosexual characters can lead to increased acceptance, or homosexual characters serve to reaffirm negative stereotypes. We seek to bridge these two bodies of research by introducing the concept of stereotyped identification-the idea that cognitively and emotionally identifying with fictional characters can increase acceptance of minorities, while reinforcing implicit stereotypes about how they look, act, and talk. Results from our national survey (N = 972) offer support for this hypothesis.

  11. Anaerobic Oxidation of Benzene by the Hyperthermophilic Archaeon Ferroglobus placidus▿†

    Science.gov (United States)

    Holmes, Dawn E.; Risso, Carla; Smith, Jessica A.; Lovley, Derek R.

    2011-01-01

    Anaerobic benzene oxidation coupled to the reduction of Fe(III) was studied in Ferroglobus placidus in order to learn more about how such a stable molecule could be metabolized under strict anaerobic conditions. F. placidus conserved energy to support growth at 85°C in a medium with benzene provided as the sole electron donor and Fe(III) as the sole electron acceptor. The stoichiometry of benzene loss and Fe(III) reduction, as well as the conversion of [14C]benzene to [14C]carbon dioxide, was consistent with complete oxidation of benzene to carbon dioxide with electron transfer to Fe(III). Benzoate, but not phenol or toluene, accumulated at low levels during benzene metabolism, and [14C]benzoate was produced from [14C]benzene. Analysis of gene transcript levels revealed increased expression of genes encoding enzymes for anaerobic benzoate degradation during growth on benzene versus growth on acetate, but genes involved in phenol degradation were not upregulated during growth on benzene. A gene for a putative carboxylase that was more highly expressed in benzene- than in benzoate-grown cells was identified. These results suggest that benzene is carboxylated to benzoate and that phenol is not an important intermediate in the benzene metabolism of F. placidus. This is the first demonstration of a microorganism in pure culture that can grow on benzene under strict anaerobic conditions and for which there is strong evidence for degradation of benzene via clearly defined anaerobic metabolic pathways. Thus, F. placidus provides a much-needed pure culture model for further studies on the anaerobic activation of benzene in microorganisms. PMID:21742914

  12. Identifying attentional bias and emotional response after appearance-related stimuli exposure.

    Science.gov (United States)

    Cho, Ara; Kwak, Soo-Min; Lee, Jang-Han

    2013-01-01

    The effect of media images has been regarded as a significant variable in the construction or in the activation of body images. Individuals who have a negative body image use avoidance coping strategies to minimize damage to their body image. We identified attentional biases and negative emotional responses following exposure to body stimuli. Female university students were divided into two groups based on their use of avoidance coping strategies (high-level group: high avoidance [HA]; low-group: low avoidance [LA]), and were assigned to two different conditions (exposure to thin body pictures, ET, and exposure to oversized body pictures, EO). Results showed that the HA group paid more attention to slim bodies and reported more negative emotions than the LA group, and that the EO had more negative effects than the ET. We suggest that HAs may attend more to slim bodies as a way of avoiding overweight bodies, influenced by social pressure, and in the search for a compensation of a positive emotional balance. However, attentional bias toward slim bodies can cause an upward comparison process, leading to increased body dissatisfaction, which is the main factor in the development of eating disorders (EDs). Therefore, altering avoidance coping strategies should be considered for people at risk of EDs.

  13. Identification of genes specifically required for the anaerobic metabolism of benzene in Geobacter metallireducens

    DEFF Research Database (Denmark)

    Zhang, Tian; Tremblay, Pier-Luc; Chaurasia, Akhilesh Kumar

    2014-01-01

    Although the biochemical pathways for the anaerobic degradation of many of the hydrocarbon constituents in petroleum reservoirs have been elucidated, the mechanisms for anaerobic activation of benzene, a very stable molecule, are not known. Previous studies have demonstrated that Geobacter...... metallireducens can anaerobically oxidize benzene to carbon dioxide with Fe(III) as the sole electron acceptor and that phenol is an intermediate in benzene oxidation. In an attempt to identify enzymes that might be involved in the conversion of benzene to phenol, whole-genome gene transcript abundance...... was compared in cells metabolizing benzene and cells metabolizing phenol. Eleven genes had significantly higher transcript abundance in benzene-metabolizing cells. Five of these genes had annotations suggesting that they did not encode proteins that could be involved in benzene metabolism and were not further...

  14. Spatial-temporal modeling of the association between air pollution exposure and preterm birth: identifying critical windows of exposure.

    Science.gov (United States)

    Warren, Joshua; Fuentes, Montserrat; Herring, Amy; Langlois, Peter

    2012-12-01

    Exposure to high levels of air pollution during the pregnancy is associated with increased probability of preterm birth (PTB), a major cause of infant morbidity and mortality. New statistical methodology is required to specifically determine when a particular pollutant impacts the PTB outcome, to determine the role of different pollutants, and to characterize the spatial variability in these results. We develop a new Bayesian spatial model for PTB which identifies susceptible windows throughout the pregnancy jointly for multiple pollutants (PM(2.5) , ozone) while allowing these windows to vary continuously across space and time. We geo-code vital record birth data from Texas (2002-2004) and link them with standard pollution monitoring data and a newly introduced EPA product of calibrated air pollution model output. We apply the fully spatial model to a region of 13 counties in eastern Texas consisting of highly urban as well as rural areas. Our results indicate significant signal in the first two trimesters of pregnancy with different pollutants leading to different critical windows. Introducing the spatial aspect uncovers critical windows previously unidentified when space is ignored. A proper inference procedure is introduced to correctly analyze these windows. © 2012, The International Biometric Society.

  15. The effect of dose, dose rate, route of administration, and species on tissue and blood levels of benzene metabolites

    International Nuclear Information System (INIS)

    Henderson, R.F.; Sabourin, P.J.; Bechtold, W.E.; Griffith, W.C.; Medinsky, M.A.; Birnbaum, L.S.; Lucier, G.W.

    1989-01-01

    Studies were completed in F344/N rats and B6C3F 1 mice to determine the effect of dose, dose rate, route of administration, and rodent species on formation of total and individual benzene metabolites. Oral doses of 50 mg/kg or higher saturated the capacity for benzene metabolism in both rats and mice, resulting in an increased proportion of the administered dose being exhaled as benzene. The saturating air concentration for benzene metabolism during 6-hr exposures was between 130 and 900 ppm. At the highest exposure concentration, rats exhaled approximately half of the internal dose retained at the end of the 6-hr exposure as benzene; mice exhaled only 15% as benzene. Mice were able to convert more of the inhaled benzene to metabolites than were rats. In addition, mice metabolized more of the benzene by pathways leading to the putative toxic metabolites, benzoquinone and muconaldehyde, than did rats. In both rats and mice, the effect of increasing dose, administered orally or by inhalation, was to increase the proportion of the total metabolites that were the products of detoxification pathways relative to the products of pathways leading to putative toxic metabolites. This indicates low-affinity, high-capacity pathways for detoxification and high-affinity, low-capacity pathways leading to putative toxic metabolites. If the results of rodent studied performed at high doses were used to assess the health risk at low-dose exposures to benzene, the toxicity of benzene would be underestimated

  16. The effects of benzene exposure on apoptosis in epithelial lung cells: localization by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) and the immunocytochemical localization of apoptosis-related gene products.

    Science.gov (United States)

    Weaver, C V; Liu, S-P; Lu, J-F; Lin, B-S

    2007-05-01

    Although benzene, a well-known human carcinogen, has been shown to induce apoptosis in vitro, no studies have been carried out to confirm and characterize its role in activating apoptosis in vivo. The present study investigated the effects of benzene inhalation on the epithelial cells lining the respiratory tract including bronchioles, terminal bronchioles, respiratory bronchioles and alveoli of male Sprague-Dawley rats. Inhalation of benzene 300 ppm for 7 days induced apoptotic changes in the parenchymal components in the lung that significantly exceeded the events of programmed cell death in normal control tissues. Apoptosis was confirmed by the electrophoretic analysis of internucleosomal DNA fragmentation of benzene-exposed lung tissues, which exhibited 180-200 bp laddering subunits indicative of genomic DNA degradation. Furthermore, semi-quantitative analysis of intracellular localization of terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling TUNEL) showed a significant (p respiratory bronchiolar 60.8% segmental epithelial components as well as alveolar (55%) epithelia. Analysis of immunohistochemical expression of apoptosis-related gene products also supported the hypothesis that benzene can induce apoptosis in chemosensitive target cells in the lung parenchyma. Quantitative immunhistochemistry showed a statistically significant increase p respiratory system that demonstrates that benzene inhalation induces lung cell apoptosis as confirmed by DNA electrophoresis, in situ nick end labeling, and the upregulation of apoptosis-related gene products that facilitate caspase-cleaved enzymes which lead to cell degradation via programmed cell death. These responses may represent an important defense mechanism within the parenchymal cells of the respiratory system that reduce mutational hazard and the potential carcinogenic effects of benzene-initiated pathogenesis.

  17. 40 CFR 721.10072 - Benzene, 1,1′-methylenebis[4-isocyanato-, polymer with benzenedicarboxylic acid, butyl dialkyl...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzene, 1,1â²-methylenebis , .alpha... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10072 Benzene, 1,1′-methylenebis... to reporting. (1) The chemical substance identified generically as benzene, 1,1′-methylenebis...

  18. 40 CFR 721.1225 - Benzene, 1,2-dimethyl-, poly-propene derivatives, sulfonated, po-tas-sium salts.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzene, 1,2-dimethyl-, poly-propene... Significant New Uses for Specific Chemical Substances § 721.1225 Benzene, 1,2-dimethyl-, poly-propene... reporting. (1) The chemical substance identified as benzene, 1,2-dimethyl-, polypropene derivatives...

  19. 40 CFR 721.2535 - Benzene, 1,1′-methylanebis[4-isocyanato-, homopolymer, Bu alc.-blocked.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzene, 1,1â²-methylanebis[4... Significant New Uses for Specific Chemical Substances § 721.2535 Benzene, 1,1′-methylanebis[4-isocyanato... chemical substance identified as benzene, 1,1′-methylanebis[4-isocyanato-, homopolymer, Bu alc.-blocked...

  20. Collision lifetimes of polyatomic molecules at low temperatures: benzene-benzene vs benzene-rare gas atom collisions.

    Science.gov (United States)

    Cui, Jie; Li, Zhiying; Krems, Roman V

    2014-10-28

    We use classical trajectory calculations to study the effects of the interaction strength and the geometry of rigid polyatomic molecules on the formation of long-lived collision complexes at low collision energies. We first compare the results of the calculations for collisions of benzene molecules with rare gas atoms He, Ne, Ar, Kr, and Xe. The comparison illustrates that the mean lifetimes of the collision complexes increase monotonically with the strength of the atom-molecule interaction. We then compare the results of the atom-benzene calculations with those for benzene-benzene collisions. The comparison illustrates that the mean lifetimes of the benzene-benzene collision complexes are significantly reduced due to non-ergodic effects prohibiting the molecules from sampling the entire configuration space. We find that the thermally averaged lifetimes of the benzene-benzene collisions are much shorter than those for Xe with benzene and similar to those for Ne with benzene.

  1. Chromosome-wide aneuploidy study (CWAS) in workers exposed to an established leukemogen, benzene

    Science.gov (United States)

    Zhang, Luoping; Lan, Qing; Guo, Weihong; Hubbard, Alan E.; Li, Guilan; Rappaport, Stephen M.; McHale, Cliona M.; Shen, Min; Ji, Zhiying; Vermeulen, Roel; Yin, Songnian; Rothman, Nathaniel; Smith, Martyn T.

    2011-01-01

    Evidence suggests that de novo, therapy-related and benzene-induced acute myeloid leukemias (AML) occur via similar cytogenetic and genetic pathways, several of which involve aneuploidy, the loss or gain of chromosomes. Aneuploidy of specific chromosomes has been detected in benzene-related leukemia patients as well as in healthy benzene-exposed workers, suggesting that aneuploidy precedes and may be a potential mechanism underlying benzene-induced leukemia. Here, we analyzed the peripheral blood lymphocytes of 47 exposed workers and 27 unexposed controls using a novel OctoChrome fluorescence in situ hybridization (FISH) technique that simultaneously detects aneuploidy in all 24 chromosomes. Through this chromosome-wide aneuploidy study (CWAS) approach, we found heterogeneity in the monosomy and trisomy rates of the 22 autosomes when plotted against continuous benzene exposure. In addition, statistically significant, chromosome-specific increases in the rates of monosomy [5, 6, 7, 10, 16 and 19] and trisomy [5, 6, 7, 8, 10, 14, 16, 21 and 22] were found to be dose dependently associated with benzene exposure. Furthermore, significantly higher rates of monosomy and trisomy were observed in a priori defined ‘susceptible’ chromosome sets compared with all other chromosomes. Together, these findings confirm that benzene exposure is associated with specific chromosomal aneuploidies in hematopoietic cells, which suggests that such aneuploidies may play roles in benzene-induced leukemogenesis. PMID:21216845

  2. MGMT hypomethylation is associated with DNA damage in workers exposed to low-dose benzene.

    Science.gov (United States)

    Li, Jie; Zhang, Xinjie; He, Zhini; Sun, Qing; Qin, Fei; Huang, Zhenlie; Zhang, Xiao; Sun, Xin; Liu, Linhua; Chen, Liping; Gao, Chen; Wang, Shan; Wang, Fangping; Li, Daochuan; Zeng, Xiaowen; Deng, Qifei; Wang, Qing; Zhang, Bo; Tang, Huanwen; Chen, Wen; Xiao, Yongmei

    2017-07-01

    This study aims to assess the effects of low-dose benzene on DNA damage and O 6 -methylguanine-DNA methyltransferase (MGMT) methylation in occupational workers. We recruited 96 nonsmoking male petrochemical industry workers exposed to low-dose benzene and 100 matched control workers. Urinary S-phenylmercapturic acid (SPMA) and S-benzylmercapturic acid (SBMA) were measured for indicating internal exposure of benzene and toluene. The degree of DNA damage was determined by the Comet assay. The levels of MGMT methylation were detected quantitatively by bisulphite-PCR pyrosequencing assay. The benzene-exposed workers had significantly higher levels of urinary SPMA, degree of DNA damage but decreased MGMT methylation than the controls (all p benzene-exposed workers and the controls. In all participants, MGMT methylation was negatively associated with the urinary SPMA and the degree of DNA damage, indicating that epigenetic regulation might be involved in response to low-dose benzene exposure-induced genetic damage. MGMT methylation could be a potent biomarker associated with low-dose benzene exposure and benzene-induced DNA damage.

  3. Alkyl-benzene-sulfonates; Alkylbenzenesulfonates

    Energy Technology Data Exchange (ETDEWEB)

    Marcou, L. [Ecole Superieure de Physique et Chimie Industrielles, 75 - Paris (France)]|[CEN, Comite europeen de normalisation (France)]|[Syndicat francais des producteurs d`agents de surface et produits auxiliaires industriels (ASPA) (France)

    1998-03-01

    The alkyl-benzene-sulfonates, or sulfophenyl-4-alkanes salts, (ABS) are anionic surface agents whose chemical formula is R-C{sub 6} H{sub 4}-SO{sub 3} M (where R is an aliphatic hydro-carbonated radical and M a metal). Like most of the surface agents, the ABS are complicated mixtures of isomers and homologues, the most usual products having 10 or 13 atoms of carbons. Their chemical preparation is carried out in two steps: 1)the alkyl-benzenes production by the alkanes or alkenes condensation on benzene 2)the alkyl-benzenes sulfonation and the neutralization of the sulfonic acids. The environmental impacts of these compounds are also given. (O.M.) 11 refs.

  4. The ototoxic effects of ethyl benzene in rats

    NARCIS (Netherlands)

    Cappaert, N.L.M.; Klis, S.F.L.; Muijser, H.; Groot, J.C.M.J. de; Kulig, B.M.; Smoorenburg, G.F.

    1999-01-01

    Exposure to organic solvents has been shown to be ototoxic in animals and there is evidence that these solvents can induce hearing loss in humans. In this study, the effects of inhalation of the possibly ototoxic solvent ethyl benzene on the cochlear function and morphology were evaluated using

  5. 76 FR 38175 - Notice of Release of the Exposure Draft Revisions to Identifying and Reporting Earmarked Funds...

    Science.gov (United States)

    2011-06-29

    ... FEDERAL ACCOUNTING STANDARDS ADVISORY BOARD Notice of Release of the Exposure Draft Revisions to Identifying and Reporting Earmarked Funds: Amending Statement of Federal Financial Accounting Standards 27... Funds: Amending Statement of Federal Financial Accounting Standards 27. The Exposure Draft is available...

  6. Detection of benzene, toluene, ethyl benzene, and xylenes (BTEX) using toluene dioxygenase-peroxidase coupling reactions.

    Science.gov (United States)

    Xu, Zhaohui; Mulchandani, Ashok; Chen, Wilfred

    2003-01-01

    We have developed a simple, whole-cell bioassay for the detection of bioavailable benzene, toluene, ethyl benzene, and xylenes (BTEX) and similar compounds. A genetically engineered E. coli strain expressing toluene dioxygenase (TDO) and toluene dihydrodiol dehydrogenase (TodD) was constructed, enabling the conversion of BTEX into their respective catechols, which were quickly converted into colored products by a horseradish peroxidase (HRP)-coupled reaction. The intensity of the color formation was correlated to concentrations of the BTEX compounds. Under the optimized conditions, a detection limit (defined as three times the standard deviation of the response obtained from the blank) of 10, 10, 20, and 50 microM was observed for benzene, toluene, ethyl benzene, and xylene, respectively. The bioassay was selective toward BTEX-related compounds with no interference observed with commonly used pesticides, herbicides, and organic solvent. The bioassay was very stable with little change in response over a 10-week period. The excellent stability suggests that the reported bioassay may be suitable for field monitoring of BTEX to identify and track contaminated water and follow the bioremediation progress.

  7. Exploring physical exposures and identifying high-risk work tasks within the floor layer trade.

    Science.gov (United States)

    McGaha, Jamie; Miller, Kim; Descatha, Alexis; Welch, Laurie; Buchholz, Bryan; Evanoff, Bradley; Dale, Ann Marie

    2014-07-01

    Floor layers have high rates of musculoskeletal disorders yet few studies have examined their work exposures. This study used observational methods to describe physical exposures within floor laying tasks. We analyzed 45 videos from 32 floor layers using Multimedia-Video Task Analysis software to determine the time in task, forces, postures, and repetitive hand movements for installation of four common flooring materials. We used the WISHA checklists to define exposure thresholds. Most workers (91%) met the caution threshold for one or more exposures. Workers showed high exposures in multiple body parts with variability in exposures across tasks and for different materials. Prolonged exposures were seen for kneeling, poor neck and low back postures, and intermittent but frequent hand grip forces. Floor layers experience prolonged awkward postures and high force physical exposures in multiple body parts, which probably contribute to their high rates of musculoskeletal disorders. Copyright © 2013 Elsevier Ltd and The Ergonomics Society. All rights reserved.

  8. Low-dose metabolism of benzene in humans: science and obfuscation

    Science.gov (United States)

    Rappaport, Stephen M.

    2013-01-01

    Benzene is a ubiquitous air pollutant that causes human leukemia and hematotoxic effects. Although the mechanism by which benzene causes toxicity is unclear, metabolism is required. A series of articles by Kim et al. used air and biomonitoring data from workers in Tianjin, China, to investigate the dose-specific metabolism (DSM) of benzene over a wide range of air concentrations (0.03–88.9 p.p.m.). Kim et al. concluded that DSM of benzene is greatest at air concentrations benzene concentrations, Price et al. argued that Kim’s methods were inappropriate for assigning benzene exposures to low exposed subjects (based on measurements of urinary benzene) and for adjusting background levels of metabolites (based on median values from the 60 lowest exposed subjects). Price et al. then performed uncertainty analyses under alternative approaches, which led them to conclude that ‘… the Tianjin data appear to be too uncertain to support any conclusions …’ regarding the DSM of benzene. They also argued that the apparent low-dose metabolism of benzene could be explained by ‘lung clearance.’ In addressing these criticisms, we show that the methods and arguments presented by Price et al. are scientifically unsound and that their results are unreliable. PMID:23222815

  9. Toxicity of Naphthalene and Benzene on Tribollium castaneum Herbst.

    Science.gov (United States)

    Pajaro-Castro, Nerlis; Caballero-Gallardo, Karina; Olivero-Verbel, Jesus

    2017-06-21

    Naphthalene and benzene are widely-used volatile organic compounds. The aim of this research was to examine the toxicological effects of naphthalene and benzene against Tribolium castaneum as an animal model. Adult insects were exposed to these aromatic compounds to assess mortality after 4-48 h of exposure. The lethal concentration 50 (LC 50 ) for naphthalene, naphthalin, and benzene were 63.6 µL/L, 20.0 µL/L, and 115.9 µL/L in air, respectively. Real-time polymerase chain reaction (PCR) analysis revealed expression changes in genes related to oxidative stress and metabolism [Glutathione S-Transferase (Gst), and Cytochrome P450 6BQ8 (Cyp6bq8)]; reproduction and metamorphosis [Hormone receptor in 39-like protein (Hr39), Ecdysone receptor: (Ecr), and Chitin synthase 2 (Chs2)]; and neurotransmission [Histamine-gated chloride channel 2 (Hiscl2)] in insects exposed for 4 h to 70.2 µL/L naphthalene. Adults exposed to benzene (80 µL/L; 4 h) overexpressed genes related to neurotransmission [GABA-gated anion channel (Rdl), Hiscl2, and GABA-gated ion channel (Grd)]; reproduction and metamorphosis [Ultraspiracle nuclear receptor (USP), Ecr; and Hr39]; and development (Chs2). The data presented here provides evidence that naphthalene and benzene inhalation are able to induce alterations on reproduction, development, metamorphosis, oxidative stress, metabolism, neurotransmission, and death of the insect.

  10. Early hematological and immunological alterations in gasoline station attendants exposed to benzene.

    Science.gov (United States)

    Moro, Angela M; Brucker, Natália; Charão, Mariele F; Sauer, Elisa; Freitas, Fernando; Durgante, Juliano; Bubols, Guilherme; Campanharo, Sarah; Linden, Rafael; Souza, Ana P; Bonorino, Cristina; Moresco, Rafael; Pilger, Diogo; Gioda, Adriana; Farsky, Sandra; Duschl, Albert; Garcia, Solange C

    2015-02-01

    Elucidation of effective biomarkers may provide tools for the early detection of biological alterations caused by benzene exposure and may contribute to the reduction of occupational diseases. This study aimed to assess early alterations on hematological and immunological systems of workers exposed to benzene. Sixty gasoline station attendants (GSA group) and 28 control subjects were evaluated. Environmental and biological monitoring of benzene exposure was performed in blood and urine. The potential effect biomarkers evaluated were δ-aminolevulinate dehydratase (ALA-D) activity, CD80 and CD86 expression in lymphocytes and monocytes, and serum interleukin-8 (IL-8). The influence of confounding factors and toluene co-exposure were considered. Although exposures were below ACGIH (American Conference of Governmental Industrial Hygienists) limits, reduced ALA-D activity, decreased CD80 and CD86 expression in monocytes and increased IL-8 levels were found in the GSA group compared to the control subjects. Furthermore, according to multiple linear regression analysis, benzene exposure was associated to a decrease in CD80 and CD86 expression in monocytes. These findings suggest, for the first time, a potential effect of benzene exposure on ALA-D activity, CD80 and CD86 expression, IL-8 levels, which could be suggested as potential markers for the early detection of benzene-induced alterations. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Accumulation of chlorinated benzenes in earthworms

    Science.gov (United States)

    Beyer, W.N.

    1996-01-01

    Chlorinated benzenes are widespread in the environment. Hexachlorobenzene, pentachlorobenzene and all isomers of dichlorobenzenes, trichlorobenzenes, and tetrachlorobenzenes, have been detected in fish, water, and sediments from the Great Lakes. This paper describes a long-term (26 week) experiment relating the concentrations of chlorinated benzenes in earthworms to 1) the length of exposure, and it describes three 8-week experiments relating concentrations of chlorinated benzenes in earthworms to 2) their concentration in soil 3) the soil organic matter content and, 4) the degree of chlorination. In the 26-week experiment, the concentration of 1,2,4 - trichlorobenzene in earthworms fluctuated only slightly about a mean of 0.63 ppm (Fig. 1). Although a statistically significant decrease can be demonstrated over the test (Pearson correlation coefficient, r = -0.62 p earthworms showed a cyclical trend that coincided with replacement of the media, and a slight but statistically significant tendency to increase from about 2 to 3 ppm over the 26 weeks (r = 0.55, p earthworms increased as the concentrations in the soil increased (Fig. 2), but leveled off at the highest soil concentrations. The most surprising result of this study was the relatively low concentrations in earthworms compared to those in soils. The average concentration of each of the six isomers of trichlorobenzene and tetrachlorobenzene in earthworms was only about 1 ppm (Table 2); the isomeric structure did not affect accumulation. The concentration of organic matter in soil had a prominent effect on hexachlorobenzene concentrations in earthworms (Fig. 3). Hexachlorobenzene concentrations decreased steadily from 9.3 ppm in earthworms kept in soil without any peat moss added to about 1 ppm in soil containing 16 or 32% organic matter.

  12. Personal exposure to volatile organic compounds in the Czech Republic.

    Science.gov (United States)

    Svecova, Vlasta; Topinka, Jan; Solansky, Ivo; Sram, Radim J

    2012-09-01

    Personal exposures to volatile organic compounds (VOCs) were measured in the three industrial cities in the Czech Republic, Ostrava, Karvina and Havirov, while the city of Prague served as a control in a large-scale molecular epidemiological study identifying the impacts of air pollution on human health. Office workers from Ostrava and city policemen from Karvina, Havirov and Prague were monitored in the winter and summer of 2009. Only adult non-smokers participated in the study (N=160). Radiello-diffusive passive samplers were used to measure the exposure to benzene, toluene, ethylbenzene, meta- plus para-xylene and ortho-xylene (BTEX). All participants completed a personal questionnaire and a time-location-activity diary (TLAD). The average personal BTEX exposure levels in both seasons were 7.2/34.3/4.4/16.1 μg/m(3), respectively. The benzene levels were highest in winter in Karvina, Ostrava and Prague: 8.5, 7.2 and 5.3 μg/m(3), respectively. The personal exposures to BTEX were higher than the corresponding stationary monitoring levels detected in the individual localities (Pfireplace or gas stove, automobile use and being in a restaurant were important predictors for benzene personal exposure. Ostrava's outdoor benzene pollution was a significant factor increasing the exposure of the Ostrava study participants in winter (P<0.05).

  13. Changes in the nervous system state and peripheral blood parameters under benzene intoxication during an experiment

    Directory of Open Access Journals (Sweden)

    R.A. Orujov

    2017-12-01

    Full Text Available Benzene is a widely spread chemical health risk factor. Our research goal was to examine the nervous system state and the blood system state under benzene intoxication during an experiment. An acute experiment was performed on 45 white mice with 5-fold poisoning with benzene; a chronic one was performed on 72 rabbits being under inhalation exposure to benzene during 4 months, its concentrations increasing and fluctuating. We determined the following blood parameters: number of reticulocytes, eosinophils, basocytes, and erythrocytes; erythrocytes sedimentation rate; blood clotting period; blood clot retraction; plasma re-calcification period; plasma tolerance to heparin; prothrombin time; prothrombin index; fibrinogen concentration; blood fibrinolytic activity; acetylcholine and choline esterase contents. We also determined adrenalin, noradrenalin, dopamine, and dihydroxyphenylalanine contents in urine. Acute experiments results revealed that one-time exposure to benzene exerted a narcotic effect on the central nervous system which had an excitation phase and inhibition phase. Under a repeat exposure to benzene animals' drug intoxication was shorter. And here neutrophils / leucocytes gradient first increased to 139.5 % from its standards value and then when down under consequent intoxications. We detected relevant changes in morphological picture of animals' peripheral blood and their central and vegetative nervous system under chronic exposure to intermittent and increasing benzene concentrations. So, our research revealed that effects exerted by benzene in small concentrations led to apparent shifts in white blood and catecholamines (adrenalin, noradrenalin, dopamine, and dihydroxyphenylalanine. We also detected certain signs that cate-cholamines endogenous reserves (dihydroxyphenylalanine were depleted and, and also signs of eosinophils-basocytes disso-ciation; such prognostic signs were considered to be unfavorable as it was exactly at that

  14. Benzene degradation in a denitrifying biofilm reactor

    OpenAIRE

    Waals, van der, Marcelle J.; Atashgahi, Siavash; Rocha, da, Ulisses Nunes; Zaan, van der, Bas M.; Smidt, Hauke; Gerritse, Jan

    2017-01-01

    Benzene is an aromatic compound and harmful for the environment. Biodegradation of benzene can reduce the toxicological risk after accidental or controlled release of this chemical in the environment. In this study, we further characterized an anaerobic continuous biofilm culture grown for more than 14 years on benzene with nitrate as electron acceptor. We determined steady state degradation rates, microbial community composition dynamics in the biofilm, and the initial anaerobic benzene degr...

  15. Progress of epidemiological and molecular epidemiological studies on benzene in China.

    Science.gov (United States)

    Li, Guilan; Yin, Songnian

    2006-09-01

    Benzene is an organic solvent that has been used in industry for about 100 years throughout the world. Since 1973, a series of toxicological and molecular epidemiological studies on benzene were conducted by researchers at the Chinese Academy of Preventive Medicine (CAPM) (1973-1986) and subsequently by a collaboration between the CAPM and the National Cancer Institute (NCI) in the United States that began in 1986, which was joined by investigators from the University of California at Berkeley, the University of North Carolina at Chapel Hill, and New York University. The findings demonstrated that the risk of leukemia and lymphoma among benzene-exposed workers was significantly increased, with elevated risks for leukemia present not only at higher exposure but also among workers exposed to under 10 ppm. Therefore, the benzene permissible level was decreased to 1.8 ppm (6 mg/m(3)) and benzene-induced leukemia is treated as an occupational cancer in China. The benzene permissible level is 1.0 in the United States and in several other developed countries and it has been suggested to be decreased to 0.5 ppm (ACGIH). A number of potential biomarkers are related to benzene exposure and poisoning. Some of these are benzene oxide-protein adducts, chromosome aberration of lymphocytes, and GPA mutations in erythrocytes, a decrease in B cell and CD4(-)T cell counts in peripheral blood, and altered expression of CXCL16, ZNF331, JUN, and PF4 in lymphocytes. Variation in multiple benzene metabolizing genes may be associated with risk of benzene hematotoxicity, including CYP2E1, MPO, NQO1, and GSTT1.

  16. Species differences in the metabolism of benzene

    Energy Technology Data Exchange (ETDEWEB)

    Henderson, R.F. [Inhalation Toxicology Research Institute, Albuquerque, NM (United States)

    1996-12-01

    The pathways of metabolism of benzene appear to be qualitatively similar in all species studied thus far. However, there are quantitative differences in the fraction of benzene metabolized by the different pathways. These species differences become important for risk assessments based on animal data. Mice have a greater overall capacity to metabolize benzene than rats or primates, based on mass balance studies conducted in vivo using radiolabled benzene. Mice and monkeys metabolize more of the benzene to hydroquinone metabolites than do rats or chimpanzees, especially at low doses. Nonhuman primates metabolize less of the benzene to muconic acid than do rodents or humans. In all species studied, a greater proportion of benzene is converted to hydroquinone and ring-breakage metabolites at low doses than at high doses. This finding should be considered in attempting to extrapolate the toxicity of benzene observed at high doses to predicted toxicity at low doses. Because ring-breakage metabolites and hydroquinone have both been implicated in the toxicity of benzene, the higher formation of those metabolites in the mouse may partially explain why mice are more sensitive to benzene than are rats. Metabolism of benzene in humans, the species of interest, does not exactly mimic that of any animal species studied. More information on the urinary and blood metabolites of occupationally exposed people is required to determine the fractional conversion of benzene to putative toxic metabolites and the degree of variability present in human subjects. 12 refs., 4 tabs.

  17. 46 CFR 30.25-3 - Benzene.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Benzene. 30.25-3 Section 30.25-3 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS GENERAL PROVISIONS Commodities Regulated § 30.25-3 Benzene. The provisions contained in 46 CFR part 197, subpart C, apply to liquid cargoes containing 0.5% or more benzene...

  18. 27 CFR 21.97 - Benzene.

    Science.gov (United States)

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Benzene. 21.97 Section 21... TREASURY LIQUORS FORMULAS FOR DENATURED ALCOHOL AND RUM Specifications for Denaturants § 21.97 Benzene. (a..., Standard No. D 836-77; for incorporation by reference, see § 21.6(b).) When 100 ml of benzene are distilled...

  19. Use of exposure history to identify patterns of immunity to pneumonia in bighorn sheep (Ovis canadensis)

    Science.gov (United States)

    Plowright, Raina K.; Manlove, Kezia; Cassirer, E. Frances; Besser, Thomas H.; Hudson, Peter J.

    2013-01-01

    Individual host immune responses to infectious agents drive epidemic behavior and are therefore central to understanding and controlling infectious diseases. However, important features of individual immune responses, such as the strength and longevity of immunity, can be challenging to characterize, particularly if they cannot be replicated or controlled in captive environments. Our research on bighorn sheep pneumonia elucidates how individual bighorn sheep respond to infection with pneumonia pathogens by examining the relationship between exposure history and survival in situ. Pneumonia is a poorly understood disease that has impeded the recovery of bighorn sheep (Ovis canadensis) following their widespread extirpation in the 1900s. We analyzed the effects of pneumonia-exposure history on survival of 388 radio-collared adults and 753 ewe-lamb pairs. Results from Cox proportional hazards models suggested that surviving ewes develop protective immunity after exposure, but previous exposure in ewes does not protect their lambs during pneumonia outbreaks. Paradoxically, multiple exposures of ewes to pneumonia were associated with diminished survival of their offspring during pneumonia outbreaks. Although there was support for waning and boosting immunity in ewes, models with consistent immunizing exposure were similarly supported. Translocated animals that had not previously been exposed were more likely to die of pneumonia than residents. These results suggest that pneumonia in bighorn sheep can lead to aging populations of immune adults with limited recruitment. Recovery is unlikely to be enhanced by translocating nai¨ve healthy animals into or near populations infected with pneumonia pathogens.

  20. Use of exposure history to identify patterns of immunity to pneumonia in bighorn sheep (Ovis canadensis.

    Directory of Open Access Journals (Sweden)

    Raina K Plowright

    Full Text Available Individual host immune responses to infectious agents drive epidemic behavior and are therefore central to understanding and controlling infectious diseases. However, important features of individual immune responses, such as the strength and longevity of immunity, can be challenging to characterize, particularly if they cannot be replicated or controlled in captive environments. Our research on bighorn sheep pneumonia elucidates how individual bighorn sheep respond to infection with pneumonia pathogens by examining the relationship between exposure history and survival in situ. Pneumonia is a poorly understood disease that has impeded the recovery of bighorn sheep (Ovis canadensis following their widespread extirpation in the 1900s. We analyzed the effects of pneumonia-exposure history on survival of 388 radio-collared adults and 753 ewe-lamb pairs. Results from Cox proportional hazards models suggested that surviving ewes develop protective immunity after exposure, but previous exposure in ewes does not protect their lambs during pneumonia outbreaks. Paradoxically, multiple exposures of ewes to pneumonia were associated with diminished survival of their offspring during pneumonia outbreaks. Although there was support for waning and boosting immunity in ewes, models with consistent immunizing exposure were similarly supported. Translocated animals that had not previously been exposed were more likely to die of pneumonia than residents. These results suggest that pneumonia in bighorn sheep can lead to aging populations of immune adults with limited recruitment. Recovery is unlikely to be enhanced by translocating naïve healthy animals into or near populations infected with pneumonia pathogens.

  1. Use of exposure history to identify patterns of immunity to pneumonia in bighorn sheep (Ovis canadensis).

    Science.gov (United States)

    Plowright, Raina K; Manlove, Kezia; Cassirer, E Frances; Cross, Paul C; Besser, Thomas E; Hudson, Peter J

    2013-01-01

    Individual host immune responses to infectious agents drive epidemic behavior and are therefore central to understanding and controlling infectious diseases. However, important features of individual immune responses, such as the strength and longevity of immunity, can be challenging to characterize, particularly if they cannot be replicated or controlled in captive environments. Our research on bighorn sheep pneumonia elucidates how individual bighorn sheep respond to infection with pneumonia pathogens by examining the relationship between exposure history and survival in situ. Pneumonia is a poorly understood disease that has impeded the recovery of bighorn sheep (Ovis canadensis) following their widespread extirpation in the 1900s. We analyzed the effects of pneumonia-exposure history on survival of 388 radio-collared adults and 753 ewe-lamb pairs. Results from Cox proportional hazards models suggested that surviving ewes develop protective immunity after exposure, but previous exposure in ewes does not protect their lambs during pneumonia outbreaks. Paradoxically, multiple exposures of ewes to pneumonia were associated with diminished survival of their offspring during pneumonia outbreaks. Although there was support for waning and boosting immunity in ewes, models with consistent immunizing exposure were similarly supported. Translocated animals that had not previously been exposed were more likely to die of pneumonia than residents. These results suggest that pneumonia in bighorn sheep can lead to aging populations of immune adults with limited recruitment. Recovery is unlikely to be enhanced by translocating naïve healthy animals into or near populations infected with pneumonia pathogens.

  2. Story of skeletally substituted benzenes

    Indian Academy of Sciences (India)

    Unknown

    corresponds to the out-of-plane distortion of the hydrogen atom connected to the heteroatoms, which is then ..... etc. exhibits significant localization.24 The skeletally substituted benzenes considered in the study with a wide ... involving cationic and anionic systems are expected to show considerable localization. In. Table 3.

  3. Comparative genomic analyses identify common molecular pathways modulated upon exposure to low doses of arsenic and cadmium

    Directory of Open Access Journals (Sweden)

    Fry Rebecca C

    2011-04-01

    Full Text Available Abstract Background Exposure to the toxic metals arsenic and cadmium is associated with detrimental health effects including cancers of various organs. While arsenic and cadmium are well known to cause adverse health effects at high doses, the molecular impact resulting from exposure to environmentally relevant doses of these metals remains largely unexplored. Results In this study, we examined the effects of in vitro exposure to either arsenic or cadmium in human TK6 lymphoblastoid cells using genomics and systems level pathway mapping approaches. A total of 167 genes with differential expression were identified following exposure to either metal with surprisingly no overlap between the two. Real-time PCR was used to confirm target gene expression changes. The gene sets were overlaid onto protein-protein interaction maps to identify metal-induced transcriptional networks. Interestingly, both metal-induced networks were significantly enriched for proteins involved in common biological processes such as tumorigenesis, inflammation, and cell signaling. These findings were further supported by gene set enrichment analysis. Conclusions This study is the first to compare the transcriptional responses induced by low dose exposure to cadmium and arsenic in human lymphoblastoid cells. These results highlight that even at low levels of exposure both metals can dramatically influence the expression of important cellular pathways.

  4. How to identify partial exposures to ionizing radiation? Proposal for a cytogenetic method

    International Nuclear Information System (INIS)

    Fernandes, T.S.; Silva, E.B.; Pinto, M.M.P.L.; Amaral, A.; Lloyd, David

    2013-01-01

    In cases of radiological incidents or in occupational exposures to ionizing radiation, the majority of exposures are not related to the total body, but only partial. In this context, if the cytogenetic dosimetry is performed, there will be an underestimation of the absorbed dose due to the dilution of irradiated cells with non-irradiated cells. Considering the norms of NR 32 - Safety and Health in the Work of Health Service - which recommends cytogenetic dosimetry in the investigation of accidental exposures to ionizing radiations, it is necessary to develop of a tool to provide a better identification of partial exposures. With this aim, a partial body exposure was simulated by mixing, in vitro, 70% of blood irradiated with 4 Gy of X-rays with 30% of unirradiated blood from the same healthy donor. Aliquots of this mixture were cultured for 48 and 72 hours. Prolonging the time of cell culture from 48 to 72 hours produced no significant change in the yield of dicentrics. However, when only M1 (first division cells) were analyzed, the frequency of dicentrics per cell was increased. Prolonging the time of cell culture allowed cells in mitotic delay by irradiation to reach metaphase, and thus provides enough time for the damage to be visualized. The results of this research present the proposed method as an important tool in the investigation of exposed individuals, allowing associating the cytogenetic analysis with the real percentage of irradiated cells, contributing significantly for the decision making in terms of occupational health. (author)

  5. 46 CFR 151.05-2 - Compliance with requirements for tank barges carrying benzene and benzene containing cargoes, or...

    Science.gov (United States)

    2010-10-01

    ... benzene and benzene containing cargoes, or butyl acrylate cargoes. 151.05-2 Section 151.05-2 Shipping... Compliance with requirements for tank barges carrying benzene and benzene containing cargoes, or butyl acrylate cargoes. A tank barge certificated to carry benzene and benzene containing cargoes or butyl...

  6. Indolent B-Cell Lymphoid Malignancy in the Spleen of a Man Who Handled Benzene: Splenic Marginal Zone Lymphoma

    Directory of Open Access Journals (Sweden)

    Jihye Lee

    2017-09-01

    Full Text Available We present the case of a 45-year-old man with a history of benzene exposure who developed splenic marginal zone lymphoma. For 6 years, he had worked in an enclosed space cleaning instruments with benzene. He was diagnosed with splenic marginal zone lymphoma 19 years after retirement. During his time of working in the laboratory in the 1980s, working environments were not monitored for hazardous materials. We indirectly estimated the cumulative level of past benzene exposure using job-exposure matrices and technical assumptions. Care must be taken in investigating the relevance of occupational benzene exposure in the occurrence of indolent B-cell lymphoma. Because of the long latency period and because occupational measurement data do not exist for the period during the patient's exposure, the epidemiological impact of benzene exposure may be underestimated.

  7. Acetyl-l-carnitine partially prevents benzene-induced hematotoxicity and oxidative stress in C3H/He mice.

    Science.gov (United States)

    Sun, Rongli; Zhang, Juan; Wei, Haiyan; Meng, Xing; Ding, Qin; Sun, Fengxia; Cao, Meng; Yin, Lihong; Pu, Yuepu

    2017-04-01

    Benzene is an environmental pollutant and occupational toxicant which induces hematotoxicity. Our previous metabonomics study suggested that acetyl-l-carnitine (ALCAR) decreased in the mouse plasma and bone marrow (BM) cells due to benzene exposure. In the present study, the topic on whether ALCAR influences hematotoxicity caused by benzene exposure was explored. Thirty-two male C3H/He mice were divided into four groups: control group (C: vehicle, oil), benzene group (150mg/kg body weight (b.w.) benzene), benzene+A1 group (150mg/kg b.w. benzene+100mg/kg b.w. ALCAR), and benzene+A2 group (150mg/kg b.w. benzene+200mg/kg b.w. ALCAR). Benzene was injected subcutaneously, and ALCAR was orally administrated via gavage once daily for 4 weeks consecutively. After the experimental period, the blood routine, BM cell number and frequency of hematopoietic stem/progenitor cell (HS/PC) were assessed. The mitochondrial membrane potential and ATP level were determined to evaluate the mitochondrial function. Reactive oxygen species (ROS), hydrogen peroxide (H 2 O 2 ) and malondialdehyde (MDA) levels were also examined, and the comet assay was performed to measure oxidative stress. Results showed that ALCAR intervention can partially reduce the benzene-induced damage on BM and HS/PCs and can simultaneously alleviate the DNA damage by reducing benzene-induced H 2 O 2, ROS, and MDA. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Leukemia risk in caprolactam workers exposed to benzene.

    Science.gov (United States)

    Swaen, Gerard M H; Scheffers, Theo; de Cock, Johan; Slangen, Jos; Drooge, Hinkelien

    2005-01-01

    To investigate the leukemia risk in a group of benzene exposed workers. We conducted a retrospective cohort mortality study on 311 men who worked between January 1, 1951 and December 31, 1968 in a Caprolactam plant in the Netherlands. In the production of Caprolactam (the Nylon 6 monomer) pure benzene is used as an extracting agent and the workers at this plant have been exposed to substantial concentrations of benzene. The cohort was followed for mortality until January 1, 2001. The total mortality was below the expected number, which was mainly caused by a deficit of cardiovascular disease mortality. In the total group, there was one death from leukemia, compared with an expected number of 1.17. Despite the substantial exposures to benzene (on average 159 ppm-years per person) there was no indication for increased leukemia mortality within the cohort. We have applied earlier quantitative risk assessments to our cohort and conclude that some of these assessments overestimate the risk observed in our cohort of Caprolactam workers.

  9. Scenarios identified internationally for occupational and public exposure to naturally occurring radioactive materials

    International Nuclear Information System (INIS)

    Fernandez Gomez, Isis Maria

    2012-01-01

    Natural radiation for decades was considered a normal phenomenon that existed in nature, so that man was conditioned to ignore; unlike artificial ionizing radiation. This mindset has changed, in the late seventies of the last century, because it has became aware of the danger that exposure to natural radiation could pose health. Studies on it have been initiated to conduct and publish. All humans are exposed to natural radiation; but, this exposure is not uniform, has depended on where they live and work, whether they have been in areas with rocks or soils particularly radioactive, their way of life, of the use of certain building materials in their homes, the use of natural gas, the use of home heating with coal. Air travel also have increased exposure to natural radiation. Ionizing radiation, whether natural or artificial, have interacted with the human body in the same way, there fore have failed to say that the natural are less or more harmful than artificial. Natural sources are grouped into two major categories. The first are the external sources: from abroad as cosmic radiation (the sun and interstellar spaces of the universe), terrestrial radiation (emitted by rocks and soil), the radiation of some buildings (e.g. granite, which can emit radon gas) and radiation contained in some foods. The second category are the internal resources: due to the presence in the human body from the environment radionuclides that are able to ionize (potassium-40, carbon-14). The naturally occurring radioactive materials (NORM for its acronym in English) have been referred to those naturally occurring radioactive materials on which any human technological activity has increased its exposure potential compared with the situation unchanged. (author) [es

  10. Prenatal radiation exposures at diagnostic procedures: methods to identify exposed pregnant patients

    International Nuclear Information System (INIS)

    Pettersson, H.; Sandborg, M.; Nilsson, J.; Olsson, S.

    2002-01-01

    Knowledge about frequency and doses to embryo/foetus from diagnostic radiology is of great importance both in the sense of estimating the radiation risks but also for optimizing the diagnostic procedures and making decisions regarding alternative procedures. In addition, the pregnant patient has the right to know the magnitude and type of radiation risks expected as a result of foetus exposure. From a risk perspective epidemiological data have shown that the embryo/foetus together with children experience higher radiation sensitivity in terms of induced leukemia and cancer compared to an adult population. Recent estimates give cancer excess lifetime mortality risks for whole body exposures of children and foetus (0-15 y age) of 0.06% (ICRP84, 2000) up to 0.14% per 10 mSv (BEIR-V 1990). In addition to the risk of cancer induction effects of cell killing, e.g. CNS abnormalities, cataracts, malformations, growth retardation, may occur. However, these effects are believed to have a threshold, about 100-200 mGy (ICRP84, 2000), and such foetus doses are rarely reached in diagnostic radiology procedures. There are 2 principal situations where foetus exposures may occur in diagnostic radiology; 1. The pregnancy of the patient is known at the time of examination, but due to the medical indications the examination can not be postponed or put forward in time, and there are no suitable alternative non-radiological procedures. 2. The pregnancy of the patient is not known at the time of examination, either due to the fact that the patient is unaware of her pregnancy or the medical personnel failed to obtain this information. The former situation may occur during the first few weeks from conception, whereas the latter situation may cover a greater gestation period

  11. Prenatal Radiation exposures at diagnostic procedures: methods to identify exposed pregnant patients

    Energy Technology Data Exchange (ETDEWEB)

    Pettersson, H.; Sandborg, M.; Nilsson, J.; Olsson, S.; Hellman, S. [Dept of Radiation Physics, Faculty of Health Sciences, Linkoeping University, Linkoeping(Sweden); Helmrot, E. [Radiology Dept, County Hospital Ryhov, Joenkoeping (Sweden); Persliden, J. [Dept of Medical Physics, Oerebro Univ Hospital, Oerebro (Sweden); Cederlund, T. [Swedish Radiation Protection Authority, Stockholm (Sweden)

    2003-06-01

    Knowledge about frequency and doses to embryo/foetus from diagnostic radiology is of great importance both in the sense of estimating the radiation risks but also for optimizing the diagnostic procedures and making decisions regarding alternative procedures. In addition, the pregnant patient has a right to know the magnitude and type of radiation risks expected as a result of foetus exposure. From a risk perspective epidemiological data has shown that the embryo/foetus together with children experience higher radiation sensitivity in terms of induced leukemia and cancer compared to an adult population. Recent estimates give cancer excess lifetime mortality risks for whole body exposures of children and foetus (0-15 y age) of 0.06% up to 0.14% per 10 mSv. In addition to the risk of cancer induction effects of cell killing, e.g. CNS abnormalities, cataracts, malformations, growth retardation, may occur. However, these effects are believed to have a threshold, about 100-200 mGy, and such foetus doses are rarely reached in diagnostic radiology procedures. There are 2 principal situations where foetus exposures may occur in diagnostic radiology; The pregnancy of the patient is known at the time of examination, but due to the medical indications the examination can not be postponed or put forward in time, and there are no suitable alternative non-radiological procedures. The pregnancy of the patient is not known at the time of examination, either due to the fact that the patient is unaware of her pregnancy or the medical personnel failed to obtain this information. The former situation may occur during the first few weeks from conception, whereas the latter situation may cover a greater gestation period. The frequency of foetus exposure is not well documented. In Sweden, there are well-established routines to track down pregnant patients before examinations are being performed. However, there are no general obligations or routines to document the cases either (i) when

  12. Identifying sources of metal exposure in organic and conventional dairy farming.

    Science.gov (United States)

    López-Alonso, M; Rey-Crespo, F; Herrero-Latorre, C; Miranda, M

    2017-10-01

    In humans the main route of exposure to toxic metals is through the diet, and there is therefore a clear need for this source of contamination to be minimized, particularly in food of animal origin. For this purpose, the various sources of toxic metals in livestock farming (which vary depending on the production system) must be taken into account. The objectives of the present study were to establish the profile of metal exposure in dairy cattle in Spain and to determine, by chemometric (multivariate statistical) analysis, any differences between organic and conventional systems. Blood samples from 522 cows (341 from organic farms and 181 from conventional farms) were analysed by inductively coupled plasma mass spectrometry to determine the concentrations of 14 elements: As, Cd, Co, Cr, Cu, Fe, Hg, I, Mn, Mo, Ni, Pb, Se and Zn. In conventional systems the generally high and balanced trace element concentrations in the mineral-supplemented concentrate feed strongly determined the metal status of the cattle. However, in organic systems, soil ingestion was an important contributing factor. Our results demonstrate that general information about the effects of mineral supplementation in conventional farming cannot be directly extrapolated to organic farming and special attention should be given to the contribution of ingestion of soil during grazing and/or ingestion of soil contaminated forage. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Assessment of benzene induced oxidative impairment in rat isolated pancreatic islets and effect on insulin secretion.

    Science.gov (United States)

    Bahadar, Haji; Maqbool, Faheem; Mostafalou, Sara; Baeeri, Maryam; Rahimifard, Mahban; Navaei-Nigjeh, Mona; Abdollahi, Mohammad

    2015-05-01

    Benzene (C6H6) is an organic compound used in petrochemicals and numerous other industries. It is abundantly released to our environment as a chemical pollutant causing widespread human exposure. This study mainly focused on benzene induced toxicity on rat pancreatic islets with respect to oxidative damage, insulin secretion and glucokinase (GK) activity. Benzene was dissolved in corn oil and administered orally at doses 200, 400 and 800mg/kg/day, for 4 weeks. In rats, benzene significantly raised the concentration of plasma insulin. Also the effect of benzene on the release of glucose-induced insulin was pronounced in isolated islets. Benzene caused oxidative DNA damage and lipid peroxidation, and also reduced the cell viability and total thiols groups, in the islets of exposed rats. In conclusion, the current study revealed that pancreatic glucose metabolism is susceptible to benzene toxicity and the resultant oxidative stress could lead to functional abnormalities in the pancreas. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. [Benzene in food and human environment].

    Science.gov (United States)

    Jedra, Małgorzata; Starski, Andrzej

    2010-01-01

    Benzene is releasing to environment in cause of industry activities. This compound is known as carcinogenic. This article contains information about benzene occurrence in people environment and sources of people exposition on this compound. Toxicology and metabolism in human organism were discussed. Benzene contamination of various food was presented on the basis of our results and also other European and American investigations and Codex Alimentarius documents. Especially formation and occurrence of benzene in non-alcoholic beverages preserved by benzoates were considered. Article describes also action, which was taken up by non-alcoholic beverages industry to mitigate benzene formation in soft drinks. National regulations concerning maximum levels of benzene in drinking water and air were also presented.

  15. Identifying areas of high risk of human exposure to coccidioidomycosis in Texas using serology data from dogs.

    Science.gov (United States)

    Gautam, R; Srinath, I; Clavijo, A; Szonyi, B; Bani-Yaghoub, M; Park, S; Ivanek, R

    2013-03-01

    Coccidioidomycosis or Valley Fever (VF) is an emerging soil-borne fungal zoonosis affecting humans and animals. Most non-human cases of VF are found in dogs, which we hypothesize may serve as sentinels for estimating the human exposure risk. The objective of this study is to use the spatial and temporal distribution and clusters of dogs seropositive for VF to define the geographic area in Texas where VF is endemic, and thus presents a higher risk of exposure to humans. The included specimens were seropositive dogs tested at a major diagnostic laboratory between 1999 and 2009. Data were aggregated by zip code and smoothed by empirical Bayesian estimation to develop an isopleth map of VF seropositive rates using kriging. Clusters of seropositive dogs were identified using the spatial scan test. Both the isopleth map and the scan test identified an area with a high rate of VF-seropositive dogs in the western and southwestern parts of Texas (relative risk = 31). This location overlapped an area that was previously identified as a potential endemic region based on human surveys. Together, these data suggest that dogs may serve as sentinels for estimating the risk of human exposure to VF. © 2012 Blackwell Verlag GmbH.

  16. Molecular epidemiology identifies HIV transmission networks associated with younger age and heterosexual exposure among Korean individuals.

    Science.gov (United States)

    Chin, Bum Sik; Chaillon, Antoine; Mehta, Sanjay R; Wertheim, Joel O; Kim, Gayeon; Shin, Hyoung-Shik; Smith, Davey M

    2016-10-01

    To evaluate if HIV transmission networks could be elucidated from data collected in a short time frame, 131 HIV-1 pol sequences were analyzed which were generated from treatment-naïve Korean individuals who were sequentially identified over 1 year. A transmission linkage was inferred when there was a genetic distance network, which demonstrated that molecular epidemiology with currently generated data (i.e., drug resistance genotypes) can be used to identify local transmission networks, even over a short timeframe. J. Med. Virol. 88:1832-1835, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  17. Using machine learning to identify air pollution exposure profiles associated with early cognitive skills among U.S. children.

    Science.gov (United States)

    Stingone, Jeanette A; Pandey, Om P; Claudio, Luz; Pandey, Gaurav

    2017-11-01

    Data-driven machine learning methods present an opportunity to simultaneously assess the impact of multiple air pollutants on health outcomes. The goal of this study was to apply a two-stage, data-driven approach to identify associations between air pollutant exposure profiles and children's cognitive skills. Data from 6900 children enrolled in the Early Childhood Longitudinal Study, Birth Cohort, a national study of children born in 2001 and followed through kindergarten, were linked to estimated concentrations of 104 ambient air toxics in the 2002 National Air Toxics Assessment using ZIP code of residence at age 9 months. In the first-stage, 100 regression trees were learned to identify ambient air pollutant exposure profiles most closely associated with scores on a standardized mathematics test administered to children in kindergarten. In the second-stage, the exposure profiles frequently predicting lower math scores were included within linear regression models and adjusted for confounders in order to estimate the magnitude of their effect on math scores. This approach was applied to the full population, and then to the populations living in urban and highly-populated urban areas. Our first-stage results in the full population suggested children with low trichloroethylene exposure had significantly lower math scores. This association was not observed for children living in urban communities, suggesting that confounding related to urbanicity needs to be considered within the first-stage. When restricting our analysis to populations living in urban and highly-populated urban areas, high isophorone levels were found to predict lower math scores. Within adjusted regression models of children in highly-populated urban areas, the estimated effect of higher isophorone exposure on math scores was -1.19 points (95% CI -1.94, -0.44). Similar results were observed for the overall population of urban children. This data-driven, two-stage approach can be applied to other

  18. Do mutations in DNMT3A/3B affect global DNA hypomethylation among benzene-exposed workers in Southeast China?: Effects of mutations in DNMT3A/3B on global DNA hypomethylation.

    Science.gov (United States)

    Zhang, Guang-Hui; Lu, Ye; Ji, Bu-Qiang; Ren, Jing-Chao; Sun, Pin; Ding, Shibin; Liao, Xiaoling; Liao, Kaiju; Liu, Jinyi; Cao, Jia; Lan, Qing; Rothman, Nathaniel; Xia, Zhao-Lin

    2017-12-01

    Global DNA hypomethylation is commonly observed in benzene-exposed workers, but the underlying mechanisms remain unclear. We sought to discover the relationships among reduced white blood cell (WBC) counts, micronuclear (MN) frequency, and global DNA methylation to determine whether there were associations with mutations in DNMT3A/3B. Therefore, we recruited 410 shoe factory workers and 102 controls from Wenzhou in Zhenjiang Province. A Methylated DNA Quantification Kit was used to quantify global DNA methylation, and single nucleotide polymorphisms (SNPs) in DNMT3A (rs36012910, rs1550117, and R882) and DNMT3B (rs1569686, rs2424909, and rs2424913) were identified using the restriction fragment length polymorphism method. A multilinear regression analysis demonstrated that the benzene-exposed workers experienced significant global DNA hypomethylation compared with the controls (β = -0.51, 95% CI: -0.69 to -0.32, P benzene exposure and that mutations in DNMTs are significantly associated with global DNA methylation, which might have influenced the induction of MN following exposure to benzene. Environ. Mol. Mutagen. 58:678-687, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  19. Ion photon-stimulated desorption as a tool to monitor the physisorption to chemisorption transition of benzene on Si(111) 7 x 7

    CERN Document Server

    Carbone, M; Casaletto, M P; Zanoni, R; Besnard-Ramage, M J; Comtet, G; Dujardin, G; Hellner, L

    2003-01-01

    We investigated the use of ion photodesorption as a tool to monitor the transition from the physisorbed to the chemisorbed state on a surface. The adsorption of benzene on Si(111) 7 x 7 in the temperature range 40-300 K is chosen as a prototype. The D sup + ion photodesorption yield was monitored as a function of temperature at various benzene exposures. Comparative measurements of the C 1s photoelectron yield in the same temperature range enable the physisorbed to chemisorbed state transition to be distinguished from that of the multilayer to the chemisorbed state. We find the onset at 110 K in the first case, and at 130-140 K in the second case. These results demonstrate that ion photodesorption is a potentially interesting method to identify physisorption to chemisorption transitions of adsorbed molecules on surfaces. (letter to the editor)

  20. Upstream petroleum industry glycol dehydrator benzene emissions status report

    International Nuclear Information System (INIS)

    1999-07-01

    The population of dehydrators referred to are located in the Western Sedimentary Basin in northeast British Columbia, Alberta and Saskatchewan, and includes units installed at wellsites, compressor stations, gas plants, central crude oil treating facilities, and reservoir or salt cavern gas storage facilities. Benzene emissions from the still column vent on glycol dehydrators occur as a result of glycol's strong affinity for aromatic hydrocarbons, including benzene. A study was carried out to: 1) develop a list of oil and gas companies operating in Canada, 2) develop an equipment and benzene emissions inventory of glycol dehydrators, 3) develop a database in Microsoft Access format to gather and maintain inventory and emission data, 4) evaluate and validate at least 10% of the reported data, 5) develop a list of companies that manufacture dehydrators and incinerators to determine how many new dehydrators were sold for use in Canada in 1998, and 6) prepare a report summarizing findings and recommendations. The companies included in the survey were the oil and gas companies identified by the Nickels' Oil and Gas Index and others provided by CAPP, CGA, and SEPAC. The project was carried out to gather glycol dehydrator equipment and still column vent benzene emissions information. 8 refs

  1. Human risk assessment of benzene after a gasoline station fuel leak

    Directory of Open Access Journals (Sweden)

    Miriam dos Anjos Santos

    2013-06-01

    Full Text Available OBJECTIVE: To assess the health risk of exposure to benzene for a community affected by a fuel leak. METHODS: Data regarding the fuel leak accident with, which occurred in the Brasilia, Federal District, were obtained from the Fuel Distributor reports provided to the environmental authority. Information about the affected population (22 individuals was obtained from focal groups of eight individuals. Length of exposure and water benzene concentration were estimated through a groundwater flow model associated with a benzene propagation model. The risk assessment was conducted according to the Agency for Toxic Substances and Disease Registry methodology. RESULTS: A high risk perception related to the health consequences of the accident was evident in the affected community (22 individuals, probably due to the lack of assistance and a poor risk communication from government authorities and the polluting agent. The community had been exposed to unsafe levels of benzene (> 5 µg/L since December 2001, five months before they reported the leak. The mean benzene level in drinking water (72.2 µg/L was higher than that obtained by the Fuel Distributer using the Risk Based Corrective Action methodology (17.2 µg/L.The estimated benzene intake from the consumption of water and food reached a maximum of 0.0091 µg/kg bw/day (5 x 10-7 cancer risk per 106 individuals. The level of benzene in water vapor while showering reached 7.5 µg/m3 for children (1 per 104 cancer risk. Total cancer risk ranged from 110 to 200 per 106 individuals. CONCLUSIONS: The population affected by the fuel leak was exposed to benzene levels that might have represented a health risk. Local government authorities need to develop better strategies to respond rapidly to these types of accidents to protect the health of the affected population and the environment.

  2. Anaerobic Benzene Oxidation by Geobacter Species

    Science.gov (United States)

    Bain, Timothy S.; Nevin, Kelly P.; Barlett, Melissa A.; Lovley, Derek R.

    2012-01-01

    The abundance of Geobacter species in contaminated aquifers in which benzene is anaerobically degraded has led to the suggestion that some Geobacter species might be capable of anaerobic benzene degradation, but this has never been documented. A strain of Geobacter, designated strain Ben, was isolated from sediments from the Fe(III)-reducing zone of a petroleum-contaminated aquifer in which there was significant capacity for anaerobic benzene oxidation. Strain Ben grew in a medium with benzene as the sole electron donor and Fe(III) oxide as the sole electron acceptor. Furthermore, additional evaluation of Geobacter metallireducens demonstrated that it could also grow in benzene-Fe(III) medium. In both strain Ben and G. metallireducens the stoichiometry of benzene metabolism and Fe(III) reduction was consistent with the oxidation of benzene to carbon dioxide with Fe(III) serving as the sole electron acceptor. With benzene as the electron donor, and Fe(III) oxide (strain Ben) or Fe(III) citrate (G. metallireducens) as the electron acceptor, the cell yields of strain Ben and G. metallireducens were 3.2 × 109 and 8.4 × 109 cells/mmol of Fe(III) reduced, respectively. Strain Ben also oxidized benzene with anthraquinone-2,6-disulfonate (AQDS) as the sole electron acceptor with cell yields of 5.9 × 109 cells/mmol of AQDS reduced. Strain Ben serves as model organism for the study of anaerobic benzene metabolism in petroleum-contaminated aquifers, and G. metallireducens is the first anaerobic benzene-degrading organism that can be genetically manipulated. PMID:23001648

  3. Reactions of benzene oxide, a reactive metabolite of benzene, with model nucleophiles and DNA.

    Science.gov (United States)

    Míčová, Kateřina; Linhart, Igor

    2012-10-01

    1. Reactivity of benzene oxide (BO), a reactive metabolite of benzene, was studied in model reactions with biologically relevant S- and N-nucleophiles by LC-ESI-MS. 2. Reaction with N-acetylcysteine (NAC) in aqueous buffer solutions gave N-acetyl-S-(6-hydroxycyclohexa-2,4-dien-1-yl)cysteine (pre-phenylmercapturic acid, PPhMA), which was easily dehydrated in acidic solutions to phenylmercapturic acid (PhMA). The yield of PPhMA + PhMA increased exponentially with pH up to 11% in the pH range from 5.5 to 11.4. 3. Primary 6-hydroxycyclohexa-2,4-dien-1-yl (HC) adducts were detected also in reactions of purine nucleosides and nucleotides under physiological conditions. After a vigorous acidic hydrolysis, all HC adducts were converted to corresponding phenyl purines, which were identified as 7-phenylguanine (7-PhG), 3-phenyladenine (3-PhA) and N(6)-phenyladenine (6-PhA). The yield of 7-PhG amounted to 14 ± 5 and 16 ± 7 ppm for 2'-deoxyguanosine and 2'-deoxyguanosine-5'-monophosphate, respectively, that of 6-PhA was 500 ± 70 and 455 ± 75 ppm with 2'-deoxyadenosine and 2'-deoxyadenosine-5'-phosphate, respectively, with only traces of 3-PhA. 4. Reactions with the DNA followed by acidic hydrolysis yielded 26 ± 11 ppm (mean ± SD; n = 9) of 7-PhG as the sole adduct detected. 5. In contrast to the reactions with S-nucleophiles, the reactivity of BO with nucleophilic sites in the DNA is very low and can therefore hardly account for a significant DNA damage caused by benzene.

  4. Gas chromatographic-mass spectroscopic determination of benzene in indoor air during the use of biomass fuels in cooking time.

    Science.gov (United States)

    Sinha, Sukesh Narayan; Kulkarni, P K; Desai, N M; Shah, S H; Patel, G M; Mansuri, M M; Parikh, D J; Saiyed, H N

    2005-02-18

    A gas chromatography-mass spectroscopic method in electron ionization (EI) mode with MS/MS ion preparation using helium at flow rate 1 ml min(-1) as carrier gas on DB-5 capillary column (30 m x 0.25 mm i.d. film thickness 0.25 microm) has been developed for the determination of benzene in indoor air. The detection limit for benzene was 0.002 microg ml(-1) with S/N: 4 (S: 66, N: 14). The benzene concentration for cooks during cooking time in indoor kitchen using dung fuel was 114.1 microg m(-3) while it was 6.6 microg m(-3) for open type kitchen. The benzene concentration was significantly higher (p analytical chemist dealing with GC-MS in confirmation and quantification of benzene in environmental samples with health risk exposure assessment.

  5. Benzene degradation in a denitrifying biofilm reactor

    NARCIS (Netherlands)

    Waals, van der Marcelle J.; Atashgahi, Siavash; Rocha, da Ulisses Nunes; Zaan, van der Bas M.; Smidt, Hauke; Gerritse, Jan

    2017-01-01

    Benzene is an aromatic compound and harmful for the environment. Biodegradation of benzene can reduce the toxicological risk after accidental or controlled release of this chemical in the environment. In this study, we further characterized an anaerobic continuous biofilm culture grown for more

  6. 29 CFR 1926.1128 - Benzene.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Benzene. 1926.1128 Section 1926.1128 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Toxic and Hazardous Substances § 1926.1128 Benzene. Note...

  7. 46 CFR 151.50-60 - Benzene.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Benzene. 151.50-60 Section 151.50-60 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES BARGES CARRYING BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-60 Benzene. The person in charge of a...

  8. 46 CFR 153.1060 - Benzene.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Benzene. 153.1060 Section 153.1060 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Operations Special Cargo Procedures § 153.1060 Benzene...

  9. 29 CFR 1915.1028 - Benzene.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Benzene. 1915.1028 Section 1915.1028 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED... Benzene. Note: The requirements applicable to shipyard employment under this section are identical to...

  10. Attitudes, Risk Behavior, and Noise Exposure among Young Adults with Hearing Problems: Identifying a Typology.

    Science.gov (United States)

    Hunter, Abby

    2017-11-01

    This study explored attitudes toward leisure noise, use of hearing protection, and perceived susceptibility to leisure-noise damage in young adults with hearing problems. Twelve participants aged between 18 and 35 years took part in a semistructured interview. Data were analyzed using framework analysis. The results showed that a positive attitude to noise, a passion for loud music, a lack of knowledge of the consequences of noise damage, and perceived low risk of hearing problems were associated with people not using earplugs. The aesthetics, comfort, perceived effects on music quality and attitude of others were all barriers to earplug use. Of those who had used earplugs, previous hearing-related symptoms and concern about future hearing damage were the main motivators for use. Four types of people were identified to describe the variation in attitudes and behaviors: those who had no change in behavior or concern about damage; those who were concerned and used earplugs; those who were concerned and avoided loud venues; and those who were concerned about communication difficulties only. Considering the wide variability, it may be more effective to shift attention from trying to change individual attitudes and behaviors to considering systemic changes to protect hearing, through ensuring the music industry and relevant authorities take greater responsibility.

  11. Anaerobic benzene degradation by Gram-positive sulfate-reducing bacteria.

    Science.gov (United States)

    Abu Laban, Nidal; Selesi, Drazenka; Jobelius, Carsten; Meckenstock, Rainer U

    2009-06-01

    Despite its high chemical stability, benzene is known to be biodegradable with various electron acceptors under anaerobic conditions. However, our understanding of the initial activation reaction and the responsible prokaryotes is limited. In the present study, we enriched a bacterial culture that oxidizes benzene to carbon dioxide under sulfate-reducing conditions. Community analysis using terminal restriction fragment length polymorphism, 16S rRNA gene sequencing and FISH revealed 95% dominance of one phylotype that is affiliated to the Gram-positive bacterial genus Pelotomaculum showing that sulfate-reducing Gram-positive bacteria are involved in anaerobic benzene degradation. In order to get indications of the initial activation mechanism, we tested the substrate utilization, performed cometabolism tests and screened for putative metabolites. Phenol, toluene, and benzoate could not be utilized as alternative carbon sources by the benzene-degrading culture. Cometabolic degradation experiments resulted in retarded rates of benzene degradation in the presence of phenol whereas toluene had no effect on benzene metabolism. Phenol, 2-hydroxybenzoate, 4-hydroxybenzoate, and benzoate were identified as putative metabolites in the enrichment culture. However, hydroxylated aromatics were shown to be formed abiotically. Thus, the finding of benzoate as an intermediate compound supports a direct carboxylation of benzene as the initial activation mechanism but additional reactions leading to its formation cannot be excluded definitely.

  12. Early life bisphenol A exposure and neurobehavior at 8years of age: Identifying windows of heightened vulnerability.

    Science.gov (United States)

    Stacy, Shaina L; Papandonatos, George D; Calafat, Antonia M; Chen, Aimin; Yolton, Kimberly; Lanphear, Bruce P; Braun, Joseph M

    2017-10-01

    Early life BPA exposure could affect neurobehavior, but few studies have investigated whether there are developmental periods when the fetus or child is more vulnerable to these potential effects. We explored windows of vulnerability to BPA exposure in a multiethnic cohort of 228 mothers and their children from Cincinnati, Ohio. We measured urinary BPA concentrations at up to two prenatal and six postnatal time points from the 2nd trimester of pregnancy until the child was age 8years. At age 8years, we administered the Behavioral Assessment System for Children-2 (BASC-2), Behavior Rating Inventory of Executive Function, and Wechsler Intelligence Scale for Children-IV. We estimated covariate-adjusted differences in composite scores from each instrument using a multiple informant model designed to identify heightened windows of vulnerability. Among all children, there was not strong evidence that the associations between BPA and neurobehavior varied by the timing of exposure (Visit x BPA p-values≥0.16). However, child sex modified the associations of repeated BPA measures with BASC-2 scores (Visit x Sex x BPA p-values=0.02-0.23). For example, each 10-fold increase in prenatal BPA was associated with more externalizing behaviors in girls (β=6.2, 95% CI: 0.8, 11.6), but not boys (β=-0.8, 95% CI: -5.0, 3.4). In contrast, a 10-fold increase in 8-year BPA was associated with more externalizing behaviors in boys (β=3.9, 95% CI: 0.6, 7.2), but not girls (β=0.3, 95% CI: -3.5, 4.1). We found that sex-dependent associations between BPA and child neurobehavior may depend on the timing of BPA exposure. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Acclimation of aerobic-activated sludge degrading benzene derivatives and co-metabolic degradation activities of trichloroethylene by benzene derivative-grown aerobic sludge.

    Science.gov (United States)

    Wang, Shizong; Yang, Qi; Bai, Zhiyong; Wang, Shidong; Wang, Yeyao; Nowak, Karolina M

    2015-01-01

    The acclimation of aerobic-activated sludge for degradation of benzene derivatives was investigated in batch experiments. Phenol, benzoic acid, toluene, aniline and chlorobenzene were concurrently added to five different bioreactors which contained the aerobic-activated sludge. After the acclimation process ended, the acclimated phenol-, benzoic acid-, toluene-, aniline- and chlorobenzene-grown aerobic-activated sludge were used to explore the co-metabolic degradation activities of trichloroethylene (TCE). Monod equation was employed to simulate the kinetics of co-metabolic degradation of TCE by benzene derivative-grown sludge. At the end of experiments, the mixed microbial communities grown under different conditions were identified. The results showed that the acclimation periods of microorganisms for different benzene derivatives varied. The maximum degradation rates of TCE for phenol-, benzoic acid-, toluene-, aniline- and chlorobenzene-grown aerobic sludge were 0.020, 0.017, 0.016, 0.0089 and 0.0047 mg g SS(-1) h(-1), respectively. The kinetic of TCE degradation in the absence of benzene derivative followed Monod equation well. Also, eight phyla were observed in the acclimated benzene derivative-grown aerobic sludge. Each of benzene derivative-grown aerobic sludge had different microbial community composition. This study can hopefully add new knowledge to the area of TCE co-metabolic by mixed microbial communities, and further the understanding on the function and applicability of aerobic-activated sludge.

  14. Epigenetic and Transcriptional Modifications in Repetitive Elements in Petrol Station Workers Exposed to Benzene and MTBE

    Directory of Open Access Journals (Sweden)

    Federica Rota

    2018-04-01

    Full Text Available Benzene, a known human carcinogen, and methyl tert-butyl ether (MTBE, not classifiable as to its carcinogenicity, are fuel-related pollutants. This study investigated the effect of these chemicals on epigenetic and transcriptional alterations in DNA repetitive elements. In 89 petrol station workers and 90 non-occupationally exposed subjects the transcriptional activity of retrotransposons (LINE-1, Alu, the methylation on repeated-element DNA, and of H3K9 histone, were investigated in peripheral blood lymphocytes. Median work shift exposure to benzene and MTBE was 59 and 408 µg/m3 in petrol station workers, and 4 and 3.5 µg/m3, in controls. Urinary benzene (BEN-U, S-phenylmercapturic acid, and MTBE were significantly higher in workers than in controls, while trans,trans-muconic acid (tt-MA was comparable between the two groups. Increased BEN-U was associated with increased Alu-Y and Alu-J expression; moreover, increased tt-MA was associated with increased Alu-Y and Alu-J and LINE-1 (L1-5′UTR expression. Among repetitive element methylation, only L1-Pa5 was hypomethylated in petrol station workers compared to controls. While L1-Ta and Alu-YD6 methylation was not associated with benzene exposure, a negative association with urinary MTBE was observed. The methylation status of histone H3K9 was not associated with either benzene or MTBE exposure. Overall, these findings only partially support previous observations linking benzene exposure with global DNA hypomethylation.

  15. Diallyl trisulfide (DATS) suppresses benzene-induced cytopenia by modulating haematopoietic cell apoptosis.

    Science.gov (United States)

    Han, Wenting; Wang, Shuo; Jiang, Lulu; Wang, Hui; Li, Ming; Wang, Xujing; Xie, Keqin

    2017-12-01

    Benzene is a well-known occupational and environmental toxicant associated with cytopenia, which is characterized by a disorder in the peripheral blood cell counts. However, no effective preventive strategy has been developed yet to tackle the exposure to benzene in daily life. The aim of this study was to evaluate the protective effects of diallyl trisulfide (DATS) on benzene-induced haematopoietic damage and to reveal its potential mechanisms of action. In our study, male Sprague-Dawley rats were divided into six groups. Rats were administered with benzene (1.3 g/kg BW by gavage) to establish the benzene poisoning model, while the DATS treatment groups were treated with benzene plus DATS (15 mg/kg, 30 mg/kg, 45 mg/kg, respectively, by gavage) for 28 days. Our results demonstrated that the counts of peripheral blood WBC and RBC decreased to 31.0% and 79.2%, respectively, in the benzene poisoning model group compared to the control. However, blood cell counts were restored by DATS treatment (30 mg/kg, 45 mg/kg). The apoptosis rates of peripheral blood mononuclear cells (PBMCs) and bone marrow cells (BMCs) were increased to 274% and 284%, respectively, following benzene exposure. Furthermore, expression levels of Bcl-2, PI3K and p-Akt were downregulated and those of Bax were upregulated in both cell types. Moreover, the oxidative parameters (oxygen species, malonaldehyde) were significantly increased, while the non-enzymatic GSH/GSSG ratios and the activities of enzymatic antioxidants (superoxide dismutase, glutathione peroxidase and catalase) were decreased. Interestingly, DATS treatment can restore the WBC number by 267.1% and 304.8% while RBC number by 108.6% and 117.7% in 30,45 mg/k DATS treated groups. In summary, we demonstrated that benzene-induced cytopenia was related to the apoptosis of PBMCs and BMCs, and DATS treatment could prevent benzene-induced cytopenia by suppressing oxidative stress-mediated cell apoptosis via the PI3K/Akt pathway. Copyright

  16. Adsorption selectivity of benzene and propene mixtures for various zeolites

    NARCIS (Netherlands)

    Ban, S.|info:eu-repo/dai/nl/304837288; van Laak, A.N.C.|info:eu-repo/dai/nl/304833223; de Jongh, P.E.|info:eu-repo/dai/nl/186125372; van der Eerden, J.P.J.M.|info:eu-repo/dai/nl/068420471; Vlugt, T.J.H.|info:eu-repo/dai/nl/205040187

    2007-01-01

    The nine-site benzene model of Zhao et al. (J. Phys. Chem. B 2005, 109, 5368-5374) has been used to systematically study the adsorption of benzene, propene, and benzene-propene mixtures in zeolites mordenite, Y, , silicalite, and MCM22. Interaction parameters for the benzene-zeolite interactions

  17. Bridging the Gap between Sample Collection and Laboratory Analysis: Using Dried Blood Spots to Identify Human Exposure to Chemical Agents.

    Science.gov (United States)

    Hamelin, Elizabeth I; Blake, Thomas A; Perez, Jonas W; Crow, Brian S; Shaner, Rebecca L; Coleman, Rebecca M; Johnson, Rudolph C

    2016-05-13

    Public health response to large scale chemical emergencies presents logistical challenges for sample collection, transport, and analysis. Diagnostic methods used to identify and determine exposure to chemical warfare agents, toxins, and poisons traditionally involve blood collection by phlebotomists, cold transport of biomedical samples, and costly sample preparation techniques. Use of dried blood spots, which consist of dried blood on an FDA-approved substrate, can increase analyte stability, decrease infection hazard for those handling samples, greatly reduce the cost of shipping/storing samples by removing the need for refrigeration and cold chain transportation, and be self-prepared by potentially exposed individuals using a simple finger prick and blood spot compatible paper. Our laboratory has developed clinical assays to detect human exposures to nerve agents through the analysis of specific protein adducts and metabolites, for which a simple extraction from a dried blood spot is sufficient for removing matrix interferents and attaining sensitivities on par with traditional sampling methods. The use of dried blood spots can bridge the gap between the laboratory and the field allowing for large scale sample collection with minimal impact on hospital resources while maintaining sensitivity, specificity, traceability, and quality requirements for both clinical and forensic applications.

  18. Bridging the gap between sample collection and laboratory analysis: using dried blood spots to identify human exposure to chemical agents

    Science.gov (United States)

    Hamelin, Elizabeth I.; Blake, Thomas A.; Perez, Jonas W.; Crow, Brian S.; Shaner, Rebecca L.; Coleman, Rebecca M.; Johnson, Rudolph C.

    2016-05-01

    Public health response to large scale chemical emergencies presents logistical challenges for sample collection, transport, and analysis. Diagnostic methods used to identify and determine exposure to chemical warfare agents, toxins, and poisons traditionally involve blood collection by phlebotomists, cold transport of biomedical samples, and costly sample preparation techniques. Use of dried blood spots, which consist of dried blood on an FDA-approved substrate, can increase analyte stability, decrease infection hazard for those handling samples, greatly reduce the cost of shipping/storing samples by removing the need for refrigeration and cold chain transportation, and be self-prepared by potentially exposed individuals using a simple finger prick and blood spot compatible paper. Our laboratory has developed clinical assays to detect human exposures to nerve agents through the analysis of specific protein adducts and metabolites, for which a simple extraction from a dried blood spot is sufficient for removing matrix interferents and attaining sensitivities on par with traditional sampling methods. The use of dried blood spots can bridge the gap between the laboratory and the field allowing for large scale sample collection with minimal impact on hospital resources while maintaining sensitivity, specificity, traceability, and quality requirements for both clinical and forensic applications.

  19. Benzene-induced genotoxicity in mice in vivo detected by the alkaline comet assay

    DEFF Research Database (Denmark)

    Tuo, J; Loft, S; Thomsen, M S

    1996-01-01

    The myelotoxic and genotoxic effects of benzene have been related to oxidative DNA damage after metabolism by CYP2E1. Single cell gel electrophoresis (alkaline comet assay) detects DNA damage and may thus be a convenient method for the study of benzene genotoxicity. Benzene exposure to NMRI mice...... as a single oral gavage at 40, 200 or 450 mg/kg resulted in dose-related DNA damage indicated by an increased comet tail length of peripheral blood lymphocytes and bone marrow nucleated cells sampled 6 h after exposure. After a dose of 40 mg/kg, there was a 1.6-fold increase of 'tail length' in bone marrow.......01). By comparing our data with those from genotoxicity studies on benzene using other methods, we conclude that the 'alkaline comet assay' is a sensitive method to detect DNA damage induced by benzene. We also infer that CYP2E1 contributes, at least partly, to the formation of the 'comet'-inducing metabolites...

  20. Gene expression profiling to identify the toxicities and potentially relevant human disease outcomes associated with environmental heavy metal exposure.

    Science.gov (United States)

    Korashy, Hesham M; Attafi, Ibraheem M; Famulski, Konrad S; Bakheet, Saleh A; Hafez, Mohammed M; Alsaad, Abdulaziz M S; Al-Ghadeer, Abdul Rahman M

    2017-02-01

    Heavy metals are the most commonly encountered toxic substances that increase susceptibility to various diseases after prolonged exposure. We have previously shown that healthy volunteers living near a mining area had significant contamination with heavy metals associated with significant changes in the expression of some detoxifying genes, xenobiotic metabolizing enzymes, and DNA repair genes. However, alterations of most of the molecular target genes associated with diseases are still unknown. Thus, the aims of this study were to (a) evaluate the gene expression profile and (b) identify the toxicities and potentially relevant human disease outcomes associated with long-term human exposure to environmental heavy metals in mining area using microarray analysis. For this purpose, 40 healthy male volunteers who were residents of a heavy metal-polluted area (Mahd Al-Dhahab city, Saudi Arabia) and 20 healthy male volunteers who were residents of a non-heavy metal-polluted area were included in the study. Total RNA was isolated from whole blood using PAXgene Blood RNA tubes and then reversed transcribed and hybridized to the gene array using the Affymetrix U219 GeneChip. Microarray analysis showed about 2129 genes were identified and differentially altered, among which a shared set of 425 genes was differentially expressed in the heavy metal-exposed groups. Ingenuity pathway analysis revealed that the most altered gene-regulated diseases in heavy metal-exposed groups included hematological and developmental disorders and mostly renal and urological diseases. Quantitative real-time polymerase chain reaction closely matched the microarray data for some genes tested. Importantly, changes in gene-related diseases were attributed to alterations in the genes encoded for protein synthesis. Renal and urological diseases were the diseases that were most frequently associated with the heavy metal-exposed group. Therefore, there is a need for further studies to validate these

  1. Identifying risk factors for exposure to culturable allergenic moulds in energy efficient homes by using highly specific monoclonal antibodies

    International Nuclear Information System (INIS)

    Sharpe, Richard A.; Cocq, Kate Le; Nikolaou, Vasilis; Osborne, Nicholas J.; Thornton, Christopher R.

    2016-01-01

    The aim of this study was to determine the accuracy of monoclonal antibodies (mAbs) in identifying culturable allergenic fungi present in visible mould growth in energy efficient homes, and to identify risk factors for exposure to these known allergenic fungi. Swabs were taken from fungal contaminated surfaces and culturable yeasts and moulds isolated by using mycological culture. Soluble antigens from cultures were tested by ELISA using mAbs specific to the culturable allergenic fungi Aspergillus and Penicillium spp., Ulocladium, Alternaria, and Epicoccum spp., Cladosporium spp., Fusarium spp., and Trichoderma spp. Diagnostic accuracies of the ELISA tests were determined by sequencing of the internally transcribed spacer 1 (ITS1)-5.8S-ITS2-encoding regions of recovered fungi following ELISA. There was 100% concordance between the two methods, with ELISAs providing genus-level identity and ITS sequencing providing species-level identities (210 out of 210 tested). Species of Aspergillus/Penicillium, Cladosporium, Ulocladium/Alternaria/Epicoccum, Fusarium and Trichoderma were detected in 82% of the samples. The presence of condensation was associated with an increased risk of surfaces being contaminated by Aspergillus/Penicillium spp. and Cladosporium spp., whereas moisture within the building fabric (water ingress/rising damp) was only associated with increased risk of Aspergillus/Penicillium spp. Property type and energy efficiency levels were found to moderate the risk of indoor surfaces becoming contaminated with Aspergillus/Penicillium and Cladosporium which in turn was modified by the presence of condensation, water ingress and rising damp, consistent with previous literature. - Highlights: • Monoclonal antibodies were used to track culturable allergenic moulds in homes. • Allergenic moulds were recovered from 82% of swabs from contaminated surfaces. • The mAbs were highly specific with 100% agreement to PCR of recovered fungi. • Improvements to energy

  2. Aromaticity of benzene in condensed phases. A case of a benzene-water system

    Science.gov (United States)

    Zborowski, Krzysztof K.

    2014-05-01

    A theoretical Density Functional Theory study was performed for a benzene molecule in water cages. Two DFT functionals (B3LYP and BLYP) were employed. The optimized geometries of the studied clusters were used to calculate the aromaticity of benzene in a condensed phase using the aromaticity indices: HOMA, NICS, PDI, and H. The results were compared with aromaticity of a single benzene molecule in the gas phase and in the solvent environment provided by the PCM continuum model. It is argued that high aromaticity of benzene in the gas phase is retained in the water environment.

  3. Benzene formation in Titan's lower atmosphere

    Science.gov (United States)

    Plane, J. M. C.; Douglas, K.; Blitz, M. A.; Heard, D. E.; Seakins, P. W.; Feng, W.; Willacy, K.

    2017-09-01

    The most distinctive feature of Saturn's moon Titan is that it is covered in a thick haze. The haze consists of organic particles called tholins, of which benzene is thought to be an important precursor. Here we examine two pathways to form benzene. The first involves reactions on cosmic dust particles, which mostly do not ablate when entering Titan's atmosphere and accumulate in the lower atmosphere. We have shown in the laboratory that acetylene molecules stick on synthetic cosmic dust at low temperatures, and react efficiently to make benzene. The second pathway is through gas phase reactions involving radical species formed through methane photochemistry. A new lab study shows that the rates of critical reactions involving these radicals vary unexpectedly at low temperatures, leading to significant changes in important benzene precursors.

  4. Three coordination compounds based on benzene tetracarboxylate ...

    Indian Academy of Sciences (India)

    YUNLONG WU

    Three coordination compounds based on benzene tetracarboxylate ligand: syntheses, structures, thermal behaviors and luminescence properties. YUNLONG WU, CHANGKUN XIA, JUN QIAN and JIMIN XIE. ∗. School of Chemistry and Chemical Engineering, Jiangsu University, Zhenjiang 212013,. People's Republic of ...

  5. Radiocarbon dating methods using benzene liquid scintillation

    International Nuclear Information System (INIS)

    Togashi, Shigeko; Matsumoto, Eiji

    1983-01-01

    The radiocarbon dating method using benzene liquid scintillation is reported in detail. The results of measurement of NBS oxalic acid agree with the recommended value, indicating that isotopic fractionation during benzene synthesis can be negligible. Ten samples which have been already measured by gas counter are dated by benzene liquid scintillation. There is no significant difference in age for the same sample between benzene liquid scintillation and gas counters. It is shown that quenching has to be corrected for the young sample. Memory effect in stainless steel reaction vessel can be removed by using an exchangeable inner vessel and by baking it in the air. Using this method, the oldest age that can be measured with 2.3 g carbon is 40,000 years B.P. (author)

  6. DNA damage and repair capacity in workers exposed to low concentrations of benzene.

    Science.gov (United States)

    Lovreglio, Piero; Doria, Denise; Fracasso, Maria Enrica; Barbieri, Anna; Sabatini, Laura; Drago, Ignazio; Violante, Francesco S; Soleo, Leonardo

    2016-03-01

    DNA damage and cellular repair capacity were studied in 18 male fuel tanker drivers and 13 male filling-station attendants exposed to low and very low concentrations of benzene, respectively, and compared to 20 males with no occupational exposure (controls). Exposure to airborne benzene was measured using passive personal samplers, and internal doses were assayed through the biomarkers t,t-muconic acid, S-phenylmercapturic acid and urinary benzene. DNA damage was evaluated using tail intensity (TI) determined by the comet assay in peripheral lymphocytes. Urinary 7-hydro-8-oxo-2'-deoxyguanosine (8-oxodG) was measured as a biomarker of oxidative damage. DNA repair kinetics were assessed using the comet assay in lymphocytes sampled 20 and 60 min post H2O2 exposure. Benzene exposure differed significantly between the drivers (median 246.3 µg/m(3)), attendants (median 13.8 µg/m(3)), and controls (median 4.1 µg/m(3)). There were no differences in TI and 8-oxodG among the three groups, or between smokers and non-smokers. DNA repair kinetics were similar among the drivers, attendants and controls, although the comet assay on H2 O2 -damaged lymphocytes after 60 min revealed significantly lower levels of TI only in drivers. The DNA repair process in smokers was similar to that observed in drivers. In conclusion, this study found no relationship between low levels of benzene exposure and DNA damage, although there was evidence that exposure interferes with DNA repair kinetics. The biological impact of this finding on the onset of genotoxic effects in exposed workers has still to be ascertained. © 2015 Wiley Periodicals, Inc.

  7. Ethyl benzene-induced ototoxicity in rats : a dose-dependent mild-frequency hearing loss

    NARCIS (Netherlands)

    Cappaert, N.L.M.; Klis, S.F.L.; Baretta, A.B.; Muijser, H.; Smoorenburg, G.F.

    2000-01-01

    Rats were exposed to ethyl benzene at 0, 300, 400 and 550 ppm for 8 hours/day for 5 consecutive days. Three to six weeks after the exposure, auditory function was tested by measuring compound action potentials (CAP) in the frequency range of 1-24 kHz and 2f1-f2 distortion product otoacoustic

  8. Alterations in leukocyte telomere length in workers occupationally exposed to Benzene

    NARCIS (Netherlands)

    Bassig, Bryan A.; Zhang, Luoping; Cawthon, Richard M.; Smith, Martyn T.; Yin, Songnian; Li, Guilan; Hu, Wei; Shen, Min; Rappaport, Stephen; Barone-Adesi, Francesco; Rothman, Nathaniel; Vermeulen, Roel; Lan, Qing

    2014-01-01

    Exposure to benzene, a known leukemogen and probable lymphomagen, has been demonstrated to result in oxidative stress, which has previously been associated with altered telomere length (TL). TL specifically has been associated with several health outcomes in epidemiologic studies, including cancer

  9. Reactions of iron atoms with benzene.

    Science.gov (United States)

    Parker, Stewart F

    2010-02-04

    The reaction of iron atoms with benzene has been studied for nearly 40 years. Despite this, there is no agreement as to the nature of the products. With the aid of density functional theory calculations of the energetics and the infrared spectra of the various species, the present work provides a rationalization of the conflicting reports regarding the nature of the products of the reaction of iron atoms with benzene in low-temperature matrices. At low temperature in dilute benzene matrices, Fe(eta(6)-C(6)H(6)) and Fe(eta(6)-C(6)H(6))(2) are the major products. At high iron concentrations, Fe(2)(eta(2)-C(6)H(6)) is also formed. In pure benzene at low temperature, Fe(eta(6)-C(6)H(6))(2) and Fe(eta(6)-C(6)H(6))(eta(4)-C(6)H(6)) are formed. None of the species undergo photoexcitation to give insertion products HFe(C(6)H(5)). In pure benzene at 77 K, Fe(eta(6)-C(6)H(6))(eta(4)-C(6)H(6)) is the major product, together with small amounts of Fe(eta(6)-C(6)H(6))(2) and iron clusters. The infrared spectra of pure benzene are complicated by the activation of infrared forbidden modes by the presence of the metal atom.

  10. Identifying Urinary and Serum Exosome Biomarkers for Radiation Exposure Using a Data Dependent Acquisition and SWATH-MS Combined Workflow

    Energy Technology Data Exchange (ETDEWEB)

    Kulkarni, Shilpa [Department of Radiation Oncology, Albert Einstein College of Medicine, Bronx, New York (United States); Koller, Antonius [Proteomics Center, Stony Brook University School of Medicine, Stony Brook, New York (United States); Proteomics Shared Resource, Herbert Irving Comprehensive Cancer Center, New York, New York (United States); Mani, Kartik M. [Department of Radiation Oncology, Albert Einstein College of Medicine, Bronx, New York (United States); Wen, Ruofeng [Department of Applied Mathematics and Statistics, Stony Brook University, Stony Brook, New York (United States); Alfieri, Alan; Saha, Subhrajit [Department of Radiation Oncology, Albert Einstein College of Medicine, Bronx, New York (United States); Wang, Jian [Center for Computational Mass Spectrometry, University of California, San Diego, California (United States); Department of Computer Science and Engineering, University of California, San Diego, California (United States); Patel, Purvi [Proteomics Shared Resource, Herbert Irving Comprehensive Cancer Center, New York, New York (United States); Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York (United States); Bandeira, Nuno [Center for Computational Mass Spectrometry, University of California, San Diego, California (United States); Department of Computer Science and Engineering, University of California, San Diego, California (United States); Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, California (United States); Guha, Chandan, E-mail: cguha@montefiore.org [Department of Radiation Oncology, Albert Einstein College of Medicine, Bronx, New York (United States); and others

    2016-11-01

    Purpose: Early and accurate assessment of radiation injury by radiation-responsive biomarkers is critical for triage and early intervention. Biofluids such as urine and serum are convenient for such analysis. Recent research has also suggested that exosomes are a reliable source of biomarkers in disease progression. In the present study, we analyzed total urine proteome and exosomes isolated from urine or serum for potential biomarkers of acute and persistent radiation injury in mice exposed to lethal whole body irradiation (WBI). Methods and Materials: For feasibility studies, the mice were irradiated at 10.4 Gy WBI, and urine and serum samples were collected 24 and 72 hours after irradiation. Exosomes were isolated and analyzed using liquid chromatography mass spectrometry/mass spectrometry-based workflow for radiation exposure signatures. A data dependent acquisition and SWATH-MS combined workflow approach was used to identify significantly exosome biomarkers indicative of acute or persistent radiation-induced responses. For the validation studies, mice were exposed to 3, 6, 8, or 10 Gy WBI, and samples were analyzed for comparison. Results: A comparison between total urine proteomics and urine exosome proteomics demonstrated that exosome proteomic analysis was superior in identifying radiation signatures. Feasibility studies identified 23 biomarkers from urine and 24 biomarkers from serum exosomes after WBI. Urinary exosome signatures identified different physiological parameters than the ones obtained in serum exosomes. Exosome signatures from urine indicated injury to the liver, gastrointestinal, and genitourinary tracts. In contrast, serum showed vascular injuries and acute inflammation in response to radiation. Selected urinary exosomal biomarkers also showed changes at lower radiation doses in validation studies. Conclusions: Exosome proteomics revealed radiation- and time-dependent protein signatures after WBI. A total of 47 differentially secreted

  11. Identifying Urinary and Serum Exosome Biomarkers for Radiation Exposure Using a Data Dependent Acquisition and SWATH-MS Combined Workflow

    International Nuclear Information System (INIS)

    Kulkarni, Shilpa; Koller, Antonius; Mani, Kartik M.; Wen, Ruofeng; Alfieri, Alan; Saha, Subhrajit; Wang, Jian; Patel, Purvi; Bandeira, Nuno; Guha, Chandan

    2016-01-01

    Purpose: Early and accurate assessment of radiation injury by radiation-responsive biomarkers is critical for triage and early intervention. Biofluids such as urine and serum are convenient for such analysis. Recent research has also suggested that exosomes are a reliable source of biomarkers in disease progression. In the present study, we analyzed total urine proteome and exosomes isolated from urine or serum for potential biomarkers of acute and persistent radiation injury in mice exposed to lethal whole body irradiation (WBI). Methods and Materials: For feasibility studies, the mice were irradiated at 10.4 Gy WBI, and urine and serum samples were collected 24 and 72 hours after irradiation. Exosomes were isolated and analyzed using liquid chromatography mass spectrometry/mass spectrometry-based workflow for radiation exposure signatures. A data dependent acquisition and SWATH-MS combined workflow approach was used to identify significantly exosome biomarkers indicative of acute or persistent radiation-induced responses. For the validation studies, mice were exposed to 3, 6, 8, or 10 Gy WBI, and samples were analyzed for comparison. Results: A comparison between total urine proteomics and urine exosome proteomics demonstrated that exosome proteomic analysis was superior in identifying radiation signatures. Feasibility studies identified 23 biomarkers from urine and 24 biomarkers from serum exosomes after WBI. Urinary exosome signatures identified different physiological parameters than the ones obtained in serum exosomes. Exosome signatures from urine indicated injury to the liver, gastrointestinal, and genitourinary tracts. In contrast, serum showed vascular injuries and acute inflammation in response to radiation. Selected urinary exosomal biomarkers also showed changes at lower radiation doses in validation studies. Conclusions: Exosome proteomics revealed radiation- and time-dependent protein signatures after WBI. A total of 47 differentially secreted

  12. Identifying inequitable exposure to toxic air pollution in racialized and low-income neighbourhoods to support pollution prevention

    Directory of Open Access Journals (Sweden)

    Suzanne Kershaw

    2013-05-01

    Full Text Available Numerous environmental justice studies have confirmed a relationship between population characteristics such as low-income or minority status and the location of environmental health hazards. However, studies of the health risks from exposure to harmful substances often do not consider their toxicological characteristics. We used two different methods, the unit-hazard and the distance-based approach, to evaluate demographic and socio-economic characteristics of the population residing near industrial facilities in the City of Toronto, Canada. In addition to the mass of air emissions obtained from the national pollutant release inventory (NPRI, we also considered their toxicity using toxic equivalency potential (TEP scores. Results from the unit-hazard approach indicate no significant difference in the proportion of low-income individuals living in host versus non-host census tracts (t(107 = 0.3, P = 0.735. However, using the distance-based approach, the proportion of low-income individuals was significantly higher (+5.1%, t(522 = 6.0, P <0.001 in host tracts, while the indicator for “racialized” communities (“visible minority” was 16.1% greater (t(521 = 7.2, P <0.001 within 2 km of a NPRI facility. When the most toxic facilities by non-carcinogenic TEP score were selected, the rate of visible minorities living near the most toxic NPRI facilities was significantly higher (+12.9%, t(352 = 3.5, P = 0.001 than near all other NPRI facilities. TEP scores were also used to identify areas in Toronto that face a double burden of poverty and air toxics exposure in order to prioritise pollution prevention.

  13. Radiolysis of Aqueous Benzene Solutions

    International Nuclear Information System (INIS)

    Christensen, H.

    1964-05-01

    Aerated and deaerated aqueous solutions of benzene have been irradiated with 60 Co γ-rays. The products of radiolysis in deaerated, unbuffered or acid, solutions were phenol, biphenyl, hydrogen and in acid solutions also hydrogen peroxide with the following yields: G(phenol) = 0. 37 (0. 37), G(biphenyl) = 1.3 (1.7), G(H 2 ) = 0.44 (0. 43) and G(H 2 O 2 ) = 0 (0.60), the figures in brackets giving the results for acid solutions. The results are shown to agree with the conclusion that k(e - aq + H 2 O 2 ) >> k(H + H 2 O 2 ). Furthermore, the results indicate that a competition takes place between the reactions: 2 C 6 H 6 OH · -> dimer -> biphenyl. C 6 H 7 · + C 6 H 6 OH · -> dimer -> biphenyl. The yields in aerated, unbuffered or acid, solutions were: G(phenol) = 2.1 (2.3), G(biphenyl) = 0 (0), and G(H 2 O 2 ) = 2.2 (3.1), the figures in brackets being valid for acid solutions. The ratio k(H + C 6 H 6 )/k(H + O 2 ) was 1.4x10 -2 . The results indicate that peroxides, or more probably hydroperoxides, take part in the reactions. After the addition of Fe 2+ or Fe 3+ to aerated acid solutions G(phenol) was increased to 6.6 and 3.4 respectively. Oxygen was consumed more rapidly in the presence of Fe. Reaction mechanisms are discussed

  14. Anaerobic Benzene Oxidation via Phenol in Geobacter metallireducens

    Science.gov (United States)

    Tremblay, Pier-Luc; Chaurasia, Akhilesh Kumar; Smith, Jessica A.; Bain, Timothy S.; Lovley, Derek R.

    2013-01-01

    Anaerobic activation of benzene is expected to represent a novel biochemistry of environmental significance. Therefore, benzene metabolism was investigated in Geobacter metallireducens, the only genetically tractable organism known to anaerobically degrade benzene. Trace amounts (benzene to carbon dioxide with the reduction of Fe(III). Phenol was not detected in cell-free controls or in Fe(II)- and benzene-containing cultures of Geobacter sulfurreducens, a Geobacter species that cannot metabolize benzene. The phenol produced in G. metallireducens cultures was labeled with 18O during growth in H218O, as expected for anaerobic conversion of benzene to phenol. Analysis of whole-genome gene expression patterns indicated that genes for phenol metabolism were upregulated during growth on benzene but that genes for benzoate or toluene metabolism were not, further suggesting that phenol was an intermediate in benzene metabolism. Deletion of the genes for PpsA or PpcB, subunits of two enzymes specifically required for the metabolism of phenol, removed the capacity for benzene metabolism. These results demonstrate that benzene hydroxylation to phenol is an alternative to carboxylation for anaerobic benzene activation and suggest that this may be an important metabolic route for benzene removal in petroleum-contaminated groundwaters, in which Geobacter species are considered to play an important role in anaerobic benzene degradation. PMID:24096430

  15. Best management practices for the control of benzene emissions from glycol dehydrators

    International Nuclear Information System (INIS)

    1997-11-01

    The effective management of benzene emissions from the upstream oil and gas industry in Canada was discussed. The processing of natural gas makes use of any one of following three glycols for dehydration: triethylene glycol, diethylene glycol, and ethylene glycol. The three factors that influence the need for dehydration are: (1) process requirements for water content in the gas stream, (2) potential for hydrate formation, and (3) corrosion protection. Alternatives to glycol dehydration include: (1) methanol or glycol injection, (2) separator packages, and (3) line heaters. An overview of the main properties of benzene was also presented. Human health risks and risk controls associated with exposure to benzene in the workplace and in domestic environments were reviewed. Industry, recognizing its responsibility, has agreed to minimize health risks related to benzene emissions from glycol dehydrator operations by progressively reducing benzene emissions. A target of 90 per cent reduction from the 1995 national emissions baseline has been established for the year 2005. 23 refs., 4 tabs

  16. Multi-scale simulation on solid benzene

    Science.gov (United States)

    Liu, Hua; Heinz, Hendrik

    2009-03-01

    Solid Benzene is used in organic semiconductors for photovoltaics, which often include pi-conjugated systems. We use MD simulations method to explore the relationship between the structure and interaction energy of two kinds of solid benzene, with the Pbca and P21c crystallgraphic structures respectively. Simple relevant force fields (PCFF and CVFF) are examined with regard to their performance on the structure and energetics of benzene dimers and benzene crystals which serve as well characterized model systems. However, MD simulations cannot get the transport properties. So the combination of reliable classical atomistic simulations and quantum-mechanical methods is needed to understand the dynamics of charge transport and self-assembly processes involving pi-conjugated oligomers and polymers. As alternative and accurate models, we explore atomistic models with additional sites which represent the location of the pi electrons and are characterized by suitable charges and van-der-Waals parameters. With these parameters, it will be possible to reproduce the dimer geometries and energies, the crystal structure of solid benzene, as well as pi-stacking forces and free energies for similar systems.

  17. Evaluation of chromosome aberration and micronucleus frequencies in blood lymphocytes of workers exposed to low concentrations of benzene.

    Science.gov (United States)

    Lovreglio, Piero; Maffei, Francesca; Carrieri, Mariella; D'Errico, Maria N; Drago, Ignazio; Hrelia, Patrizia; Bartolucci, Giovanni B; Soleo, Leonardo

    2014-08-01

    The frequency of chromosome aberrations (CA) and micronuclei (MN) was investigated in the peripheral lymphocytes of workers occupationally exposed to low or very low concentrations of benzene. The study included 43 exposed workers (all males), namely 19 fuel-tanker drivers and 24 filling-station attendants, and 31 male subjects with no occupational exposure to the toxicant (controls). Benzene exposure was verified by means of environmental monitoring with passive personal samplers (Radiello(®)), and through biological monitoring, i.e. by measurement of urinary trans,trans-muconic acid, S-phenylmercapturic acid and benzene. The frequency of CA and MN in peripheral lymphocytes was determined according to standard procedures. Exposure to benzene was found to be significantly higher for fuel-tanker drivers (median 246.6 μg/m(3)) than for filling-station attendants (median 19.9 μg/m(3)). Both groups had significantly higher exposure than controls (median 4.3 μg/m(3)). No increased frequency of CA and MN was observed in either fuel-tanker drivers or filling-station attendants compared with controls. In all subjects examined as a single group, the frequency of MN was significantly dependent on age. Only in the fuel-tanker drivers was the frequency of MN found to depend not only on age, but also on exposure to benzene. In conclusion, the frequency of MN, but not of CA, could be influenced by exposure to benzene concentrations of up to one order of magnitude lower than the threshold limit value (time-weighted average). Copyright © 2014 Elsevier B.V. All rights reserved.

  18. A retrospective cohort study of leukemia and other cancers in benzene workers

    Energy Technology Data Exchange (ETDEWEB)

    Yin, S.N.; Li, G.L.; Tain, F.D.; Fu, Z.I.; Jin, C. (Chinese Academy of Preventive Medicine, Beijing (China)); Chen, Y.J. (Station for Health and Prevention of Infection of Shanghai (China)); Luo, S.J. (Station for Health and Prevention of Infection of Sichuan (China)); Ye, P.Z. (Station for Health and Prevention of Infection of Tianjin (China)); Zhang, J.Z. (Station for Health and Prevention of Infection of Nanchang (China)); Wang, G.C. (China Institute for Prevention and Treatment of Occupational Disease of Heilongjing (China)); Zhang, X.C. (China Institute for Prevention and Treatment of Occupational Disease of Shenyang (China)); Wu, H.N. (China Institute for Prevention and Treatment of Occupational Disease of Helan (China)); Zhong, Q.C. (China Institute for Prevention and Treatment of Occupational Disease of Guangzhou (China))

    1989-07-01

    A retrospective cohort study was carried out in 1982-1983 among 28,460 benzene-exposed workers (15,643 males, 12,817 females) from 233 factories and 28,257 control workers (16,621 males, 12,366 females) from 83 factories in 12 large cities in China. All-cause mortality was significantly higher among the exposed than among the unexposed, as was mortality from all malignant neoplasms. For certain cancers, increased mortality was noted among benzene-exposed males in comparison with that among unexposed males; the standardized mortality ratios (SMR) were elevated for leukemia, lung cancer, primary hepatocarcinoma, and stomach cancer. For females only leukemia occurred in excess among the exposed. Risk of leukemia rose as duration to exposure to benzene increased up to 15 years, and then declined with additional years of exposure. Leukemia occurred among some workers with as little as 6 to 10 ppm average exposure and 50 ppm-years (or possibly less) cumulative lifetime exposure. During 1972 to 1981, the annual incidence of leukemia ranged from 5.83 to 28.33 per 100,000 with higher rates occurring in the interval 1977 to 1981 than in the earlier years of the study period. Future studies should evaluate more precisely the relationship between exposure levels, job title, and development of leukemia among cases and noncases within the exposed cohort.

  19. WORKSHOP TO IDENTIFY CRITICAL WINDOWS OF EXPOSURE FOR CHILDREN'S HEALTH: REPRODUCTIVE HEALTH IN CHILDREN AND ADOLESCENTS WORK GROUP SUMMARY

    Science.gov (United States)

    This workgroup report addresses the central question: what are the critical windows during development (pre-conception through puberty) when exposure to xenobiotics may have the greatest adverse impact on subsequent reproductive health. The reproductive system develops in stages...

  20. Soil adsorption alters bioavailability of benzene in dermally exposed male rats.

    Science.gov (United States)

    Skowronski, G A; Turkall, R M; Abdel-Rahman, M S

    1988-10-01

    The potential for exposure to chemically contaminated soil is a concern for chemical industry and waste disposal site workers as well as for individuals living near the contamination site. Current assessment of potential health risks from these types of exposures relies almost exclusively on extrapolations from data derived with pure chemicals. Complex interactions with soil, however, may alter greatly the way in which a chemical subsequently interacts with the body. This study was conducted to determine if soil adsorption alters the way in which benzene, a common chemical contaminant, enters and is handled by the body following dermal exposure. A shallow glass cap covering approximately a 13-cm2 area was fixed tightly to the shaved skin of each adult male rat tested; 300 microL of 14C-benzene alone or with 1 g of clay or sandy soil was introduced under the cap through an opening which was sealed immediately. Pure benzene produced the highest peak plasma concentration of radioactivity, followed closely by sandy soil-adsorbed benzene, with the lowest value exhibited by clay soil-adsorbed benzene. The plasma elimination half-lives were as follows:sandy (24.5 hr), pure (23.0 hr), and clay (19.4 hr). The tissue concentrations of radioactivity 48 hr post administration were highest in treated skin (covered by the glass cap), followed by the kidney and liver in both soil-treated groups, and were highest in the kidney followed by the liver and treated skin in the pure group.(ABSTRACT TRUNCATED AT 250 WORDS)

  1. Benzene derivatives produced by Fusarium graminearum - Short communication.

    Science.gov (United States)

    Ntushelo, Khayalethu; Setshedi, Itumeleng

    2015-06-01

    Using NMR spectroscopy benzene derivatives were detected in mycelia of Fusarium graminearum, a pathogen of wheat and maize. In previous studies F. graminearum was found to cause cancer to humans and benzene derivatives were detected in breath of cancer sufferers. Surprisingly, no study found benzene derivatives to be the cancerous agents in F. graminearum. In this study we detected benzene derivatives in F. graminearum and propose to study their role as cancer agents.

  2. 40 CFR 721.1187 - Bis(imidoethylene) benzene.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Bis(imidoethylene) benzene. 721.1187... Substances § 721.1187 Bis(imidoethylene) benzene. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance bis(imidoethylene)benzene (PMN P-93-1447) is subject to reporting...

  3. Recommended sublimation pressure and enthalpy of benzene

    Czech Academy of Sciences Publication Activity Database

    Růžička, K.; Fulem, Michal; Červinka, C.

    2014-01-01

    Roč. 68, Jan (2014), s. 40-47 ISSN 0021-9614 Institutional support: RVO:68378271 Keywords : benzene * vapor pressure * heat capacity * ideal-gas thermodynamic properties * sublimation enthalpy * recommended vapor pressure Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.679, year: 2014

  4. Three coordination compounds based on benzene tetracarboxylate ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 129; Issue 8. Three coordination compounds based on benzene tetracarboxylate ligand: syntheses, structures, thermal behaviors and luminescence properties. YUNLONG WU CHANGKUN XIA JUN QIAN JIMIN XIE. REGULAR ARTICLE Volume 129 Issue 8 August ...

  5. Formation of Benzene in the Interstellar Medium

    Science.gov (United States)

    Jones, Brant M.; Zhang, Fangtong; Kaiser, Ralf I.; Jamal, Adeel; Mebel, Alexander M.; Cordiner, Martin A.; Charnley, Steven B.; Crim, F. Fleming (Editor)

    2010-01-01

    Polycyclic aromatic hydrocarbons and related species have been suggested to play a key role in the astrochemical evolution of the interstellar medium, but the formation mechanism of even their simplest building block-the aromatic benzene molecule-has remained elusive for decades. Here we demonstrate in crossed molecular beam experiments combined with electronic structure and statistical calculations that benzene (C6H6) can be synthesized via the barrierless, exoergic reaction of the ethynyl radical and 1,3- butadiene, C2H + H2CCHCHCH2 --> C6H6, + H, under single collision conditions. This reaction portrays the simplest representative of a reaction class in which aromatic molecules with a benzene core can be formed from acyclic precursors via barrierless reactions of ethynyl radicals with substituted 1,3-butadlene molecules. Unique gas-grain astrochemical models imply that this low-temperature route controls the synthesis of the very first aromatic ring from acyclic precursors in cold molecular clouds, such as in the Taurus Molecular Cloud. Rapid, subsequent barrierless reactions of benzene with ethynyl radicals can lead to naphthalene-like structures thus effectively propagating the ethynyl-radical mediated formation of aromatic molecules in the interstellar medium.

  6. Organocalcium-mediated nucleophilic alkylation of benzene.

    Science.gov (United States)

    Wilson, Andrew S S; Hill, Michael S; Mahon, Mary F; Dinoi, Chiara; Maron, Laurent

    2017-12-01

    The electrophilic aromatic substitution of a C-H bond of benzene is one of the archetypal transformations of organic chemistry. In contrast, the electron-rich π-system of benzene is highly resistant to reactions with electron-rich and negatively charged organic nucleophiles. Here, we report that this previously insurmountable electronic repulsion may be overcome through the use of sufficiently potent organocalcium nucleophiles. Calcium n -alkyl derivatives-synthesized by reaction of ethene, but-1-ene, and hex-1-ene with a dimeric calcium hydride-react with protio and deutero benzene at 60°C through nucleophilic substitution of an aromatic C-D/H bond. These reactions produce the n- alkyl benzenes with regeneration of the calcium hydride. Density functional theory calculations implicate an unstabilized Meisenheimer complex in the C-H activation transition state. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  7. Formation of benzene in the interstellar medium

    Science.gov (United States)

    Jones, Brant M.; Zhang, Fangtong; Kaiser, Ralf I.; Jamal, Adeel; Mebel, Alexander M.; Cordiner, Martin A.; Charnley, Steven B.

    2011-01-01

    Polycyclic aromatic hydrocarbons and related species have been suggested to play a key role in the astrochemical evolution of the interstellar medium, but the formation mechanism of even their simplest building block—the aromatic benzene molecule—has remained elusive for decades. Here we demonstrate in crossed molecular beam experiments combined with electronic structure and statistical calculations that benzene (C6H6) can be synthesized via the barrierless, exoergic reaction of the ethynyl radical and 1,3-butadiene, C2H + H2CCHCHCH2 → C6H6 + H, under single collision conditions. This reaction portrays the simplest representative of a reaction class in which aromatic molecules with a benzene core can be formed from acyclic precursors via barrierless reactions of ethynyl radicals with substituted 1,3-butadiene molecules. Unique gas-grain astrochemical models imply that this low-temperature route controls the synthesis of the very first aromatic ring from acyclic precursors in cold molecular clouds, such as in the Taurus Molecular Cloud. Rapid, subsequent barrierless reactions of benzene with ethynyl radicals can lead to naphthalene-like structures thus effectively propagating the ethynyl-radical mediated formation of aromatic molecules in the interstellar medium. PMID:21187430

  8. Self-diffusion in benzene-toluene and benzene-cyclohexane solutions

    International Nuclear Information System (INIS)

    Reimschuessel, W.; Hawlicka, E.

    1977-01-01

    The self-diffusion in benzene-toluene and benzene-cyclohexane solutions have been measured at different temperatures. The capillary-cell method was employed. The activation parameters of self-diffusion for the systems are presented. The data have been used to test the validity of various diffusion equations proposed in the literature. The hypothesis that the self-diffusion was realized by movement of aggregates of molecules is suggested. (orig.) [de

  9. Removal efficiencies of constructed wetland and efficacy of plant on treating benzene

    Directory of Open Access Journals (Sweden)

    Florencio Ballesteros, Jr.

    2016-03-01

    Full Text Available Leaking underground petroleum storage poses human and environmental health risks as it contaminates the soil and the groundwater. Of the many contaminants, benzene – a major constituent of gasoline, is of primary concern. It is an identified carcinogen with a permissible limit set at a low level of 0.005 mg L−1. This poses technical and regulatory challenge to remediation of contaminated sites. Various specialized treatment methods are available, but despite of the high removal efficiencies of sophisticated treatments, the residual level still poses health risks. Thus, additional alternative ways that are cost effective and require minimum technical expertise are necessary, and a constructed wetland (CW is a potential alternative. This study evaluates the performance of a surface flow type CW for the removal of benzene from the contaminated water. It further determines the efficacy of a common reed plant Phragmites karka in treating benzene. Planted and unplanted CW were acclimated with benzene for 16 wk and tested for an 8-d hydraulic retention time at benzene levels of 66 and 45 mg L−1. Results indicate that the planted CW performed better and gave reliable and stable results.

  10. Urinary benzene biomarkers and DNA methylation in Bulgarian petrochemical workers: study findings and comparison of linear and beta regression models.

    Directory of Open Access Journals (Sweden)

    Wei Jie Seow

    Full Text Available Chronic occupational exposure to benzene is associated with an increased risk of hematological malignancies such as acute myeloid leukemia (AML, but the underlying mechanisms are still unclear. The main objective of this study was to investigate the association between benzene exposure and DNA methylation, both in repeated elements and candidate genes, in a population of 158 Bulgarian petrochemical workers and 50 unexposed office workers. Exposure assessment included personal monitoring of airborne benzene at work and urinary biomarkers of benzene metabolism (S-phenylmercapturic acid [SPMA] and trans,trans-muconic acid [t,t-MA] at the end of the work-shift. The median levels of airborne benzene, SPMA and t,t-MA in workers were 0.46 ppm, 15.5 µg/L and 711 µg/L respectively, and exposure levels were significantly lower in the controls. Repeated-element DNA methylation was measured in Alu and LINE-1, and gene-specific methylation in MAGE and p15. DNA methylation levels were not significantly different between exposed workers and controls (P>0.05. Both ordinary least squares (OLS and beta-regression models were used to estimate benzene-methylation associations. Beta-regression showed better model specification, as reflected in improved coefficient of determination (pseudo R(2 and Akaike's information criterion (AIC. In beta-regression, we found statistically significant reductions in LINE-1 (-0.15%, P<0.01 and p15 (-0.096%, P<0.01 mean methylation levels with each interquartile range (IQR increase in SPMA. This study showed statistically significant but weak associations of LINE-1 and p15 hypomethylation with SPMA in Bulgarian petrochemical workers. We showed that beta-regression is more appropriate than OLS regression for fitting methylation data.

  11. Identification of C2-C4 alkylated benzenes in flash pyrolysates of kerogens, coals and asphaltenes

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Hartgers, W.A.; Leeuw, J.W. de

    1992-01-01

    Pseudo-Kováts indices were determined for all positional isomers of C2-C4 alkylated benzenes using a non-polar capillary column (CP Sil-5). These indices were applied in combination with mass spectral data to identify these compounds in complex mixtures of a relatively non-polar nature generated

  12. Angiogenic Potential of 3-Nitro-4-Hydroxy Benzene Arsonic Acid (Roxarsone)

    OpenAIRE

    Basu, Partha; Ghosh, Richik N.; Grove, Linnette E.; Klei, Linda; Barchowsky, Aaron

    2008-01-01

    Background Roxarsone (3-nitro-4-hydroxy benzene arsonic acid) is an arsenic compound widely used in the poultry industry as a feed additive to prevent coccidiosis, stimulate growth, and to improve tissue pigmentation. Little is known about the potential human health effects from roxarsone released into the environment from chicken waste or from residual compound in chicken products. Objective The growth potentiation and enhanced tissue pigmentation suggest that low levels of roxarsone exposur...

  13. Exposure Medium: Key in Identifying Free Ag+ as the Exclusive Species of Silver Nanoparticles with Acute Toxicity to Daphnia magna

    Science.gov (United States)

    Shen, Mo-Hai; Zhou, Xiao-Xia; Yang, Xiao-Ya; Chao, Jing-Bo; Liu, Rui; Liu, Jing-Fu

    2015-04-01

    It is still not very clear what roles the various Ag species play in the toxicity of silver nanoparticles (AgNPs). In this study, we found that traditional exposure media result in uncontrollable but consistent physicochemical transformation of AgNPs, causing artifacts in determination of median lethal concentration (LC50) and hindering the identification of Ag species responsible for the acute toxicity of AgNPs to Daphnia magna. This obstacle was overcome by using 8 h exposure in 0.1 mmol L-1 NaNO3 medium, in which we measured the 8-h LC50 of seven AgNPs with different sizes and coatings, and determined the concentrations of various Ag species. The LC50 as free Ag+ of the seven AgNPs (0.37-0.44 μg L-1) agreed very well with that of AgNO3 (0.40 μg L-1), and showed the lowest value compared to that as total Ag, total Ag+, and dissolved Ag, demonstrating free Ag+ is exclusively responsible for the acute toxicity of AgNPs to D. magna, while other Ag species in AgNPs have no contribution to the acute toxicity. Our results demonstrated the great importance of developing appropriate exposure media for evaluating risk of nanomaterials.

  14. Metatranscriptome of an Anaerobic Benzene-Degrading, Nitrate-Reducing Enrichment Culture Reveals Involvement of Carboxylation in Benzene Ring Activation

    Science.gov (United States)

    Luo, Fei; Gitiafroz, Roya; Devine, Cheryl E.; Gong, Yunchen; Hug, Laura A.; Raskin, Lutgarde

    2014-01-01

    The enzymes involved in the initial steps of anaerobic benzene catabolism are not known. To try to elucidate this critical step, a metatranscriptomic analysis was conducted to compare the genes transcribed during the metabolism of benzene and benzoate by an anaerobic benzene-degrading, nitrate-reducing enrichment culture. RNA was extracted from the mixed culture and sequenced without prior mRNA enrichment, allowing simultaneous examination of the active community composition and the differential gene expression between the two treatments. Ribosomal and mRNA sequences attributed to a member of the family Peptococcaceae from the order Clostridiales were essentially only detected in the benzene-amended culture samples, implicating this group in the initial catabolism of benzene. Genes similar to each of two subunits of a proposed benzene-carboxylating enzyme were transcribed when the culture was amended with benzene. Anaerobic benzoate degradation genes from strict anaerobes were transcribed only when the culture was amended with benzene. Genes for other benzoate catabolic enzymes and for nitrate respiration were transcribed in both samples, with those attributed to an Azoarcus species being most abundant. These findings indicate that the mineralization of benzene starts with its activation by a strict anaerobe belonging to the Peptococcaceae, involving a carboxylation step to form benzoate. These data confirm the previously hypothesized syntrophic association between a benzene-degrading Peptococcaceae strain and a benzoate-degrading denitrifying Azoarcus strain for the complete catabolism of benzene with nitrate as the terminal electron acceptor. PMID:24795366

  15. Formation of reactive metabolites from benzene

    International Nuclear Information System (INIS)

    Snyder, R.; Jowa, L.; Witz, G.; Kalf, G.; Rushmore, T.

    1986-01-01

    Rat liver mitoplasts were incubated first with [ 3 H]dGTP, to form DNA labeled in G, and then with [ 14 C]benzene. The DNA was isolated and upon isopycnic density gradient centrifugation in CsCl yielded a single fraction of DNA labeled with both [ 3 H] and [ 14 C]. These data are consistent with the covalent binding of one or more metabolites of benzene to DNA. The DNA was enzymatically hydrolyzed to deoxynucleosides and chromatographed to reveal at least seven deoxyguanosine adducts. Further studies with labeled deoxyadenine revealed one adduct on deoxyadenine. [ 3 H]Deoxyguanosine was reacted with [ 14 C]hydroquinone or benzoquinone. The product was characterized using uv, fluorescence, mass and NMR spectroscopy. A proposed structure is described. (orig.)

  16. Computer simulations of homogeneous nucleation of benzene from the melt.

    Science.gov (United States)

    Shah, Manas; Santiso, Erik E; Trout, Bernhardt L

    2011-09-08

    Nucleation is the key step in crystallization by which the molecules (or atoms or ions) aggregate together, find the right relative orientations, and start to grow to form the final crystal structure. Since nucleation is an activated step involving a large gap in time scales between molecular motions and the nucleation event itself, nucleation must be studied using rare events methods. We employ a technique developed previously in our group known as aimless shooting [Peters, B.; Trout, B. L. J. Chem. Phys., 2006, 125, 054108], which is based on transition path sampling, to generate reactive trajectories between the disordered and ordered phases of benzene. Using the likelihood maximization algorithm, we analyze the aimless shooting trajectories to identify the key order parameters or collective variables to describe the reaction coordinate for the nucleation of benzene from the melt. We find that the local bond orientation and local relative orientation order parameters are the most important collective variables in describing the reaction coordinate for homogeneous nucleation from the melt, as compared to cluster size and space-averaged order parameters. This study also demonstrates the utility of recently developed order parameters for molecular crystals [Santiso, E. E.; Trout, B. L. J. Chem. Phys., 2011, 134, 064109].

  17. Irradiated Benzene Ice Provides Clues to Meteoritic Organic Chemistry

    Science.gov (United States)

    Callahan, Michael Patrick; Gerakines, Perry Alexander; Martin, Mildred G.; Hudson, Reggie L.; Peeters, Zan

    2013-01-01

    Aromatic hydrocarbons account for a significant portion of the organic matter in carbonaceous chondrite meteorites, as a component of both the low molecular weight, solvent-extractable compounds and the insoluble organic macromolecular material. Previous work has suggested that the aromatic compounds in carbonaceous chondrites may have originated in the radiation-processed icy mantles of interstellar dust grains. Here we report new studies of the organic residue made from benzene irradiated at 19 K by 0.8 MeV protons. Polyphenyls with up to four rings were unambiguously identified in the residue by gas chromatography-mass spectrometry. Atmospheric pressure photoionization Fourier transform mass spectrometry was used to determine molecular composition, and accurate mass measurements suggested the presence of polyphenyls, partially hydrogenated polyphenyls, and other complex aromatic compounds. The profile of low molecular weight compounds in the residue compared well with extracts from the Murchison and Orgueil meteorites. These results are consistent with the possibility that solid phase radiation chemistry of benzene produced some of the complex aromatics found in meteorites.

  18. Application of toxicogenomic profiling to evaluate effects of benzene and formaldehyde: from yeast to human

    Science.gov (United States)

    McHale, Cliona M.; Smith, Martyn T.; Zhang, Luoping

    2014-01-01

    Genetic variation underlies a significant proportion of the individual variation in human susceptibility to toxicants. The primary current approaches to identify gene–environment (GxE) associations, genome-wide association studies (GWAS) and candidate gene association studies, require large exposed and control populations and an understanding of toxicity genes and pathways, respectively. This limits their application in the study of GxE associations for the leukemogens benzene and formaldehyde, whose toxicity has long been a focus of our research. As an alternative approach, we applied innovative in vitro functional genomics testing systems, including unbiased functional screening assays in yeast and a near-haploid human bone marrow cell line (KBM7). Through comparative genomic and computational analyses of the resulting data, we have identified human genes and pathways that may modulate susceptibility to benzene and formaldehyde. We have validated the roles of several genes in mammalian cell models. In populations occupationally exposed to low levels of benzene, we applied peripheral blood mononuclear cell transcriptomics and chromosome-wide aneuploidy studies (CWAS) in lymphocytes. In this review of the literature, we describe our comprehensive toxicogenomic approach and the potential mechanisms of toxicity and susceptibility genes identified for benzene and formaldehyde, as well as related studies conducted by other researchers. PMID:24571325

  19. Screening-level exposure-based prioritization to identify potential POPs, vPvBs and planetary boundary threats among Arctic contaminants

    Directory of Open Access Journals (Sweden)

    Efstathios Reppas-Chrysovitsinos

    2017-06-01

    Full Text Available A report that reviews Arctic contaminants that are not currently regulated as persistent organic pollutants (POPs under international treaties was recently published by the Arctic Monitoring and Assessment Programme (AMAP. We evaluated 464 individual chemicals mentioned in the AMAP report according to hazard profiles for POPs, very persistent and very bioaccumulative (vPvB chemicals, and two novel and distinct hazard profiles we derived from the planetary boundary threat framework. The two planetary boundary threat profiles assign high priority to chemicals that will be mobile and poorly reversible environmental contaminants. Utilizing persistence as a proxy for poor reversibility, we defined two exposure-based hazard profiles; airborne persistent contaminants (APCs and waterborne persistent contaminants (WPCs that are potential planetary boundary threats. We used in silico estimates of physicochemical properties and multimedia models to calculate hazard metrics for persistence, bioaccumulation and long-range transport potential, then we synthesized this information into four exposure-based hazard scores of the potential of each AMAP chemical to fit each of the POP, vPvB, APC and WPC exposure-based hazard profiles. As an alternative to adopting a “bright line” score that represented cause for concern, we scored the AMAP chemicals by benchmarking against a reference set of 148 known and relatively well-studied contaminants and expressed their exposure-based hazard scores as percentile ranks against the scores of the reference set chemicals. Our results show that scores in the four exposure-based hazard profiles provide complementary information about the potential environmental exposure-based hazards of the AMAP chemicals. Our POP, vPvB, APC and WPC exposure-based hazard scores identify high priority chemicals for further study from among the AMAP contaminants.

  20. Genome-wide gene-asbestos exposure interaction association study identifies a common susceptibility variant on 22q13.31 associated with lung cancer risk

    Science.gov (United States)

    Liu, Chen-yu; Stücker, Isabelle; Chen, Chu; Goodman, Gary; McHugh, Michelle K.; D’Amelio, Anthony M.; Etzel, Carol J.; Li, Su; Lin, Xihong; Christiani, David C.

    2015-01-01

    Background Occupational asbestos exposure has been found to increase lung cancer risk in epidemiological studies. Methods We conducted an asbestos exposure-gene interaction analyses among several Caucasian populations who were current or ex-smokers. The discovery phase included 833 Caucasian cases and 739 Caucasian controls, and used a genome-wide association study (GWAS) to identify single nucleotide polymorphisms (SNPs) with gene-asbestos interaction effects. The top ranked SNPs from the discovery phase were replicated within the International Lung and Cancer Consortium (ILCCO). First, in silico replication was conducted in those groups that had GWAS and asbestos exposure data, including 1,548 cases and 1,527 controls. This step was followed by de novo genotyping to replicate the results from the in silico replication, and included 1,539 cases and 1,761 controls. Multiple logistic regression was used to assess the SNP-asbestos exposure interaction effects on lung cancer risk. Results We observed significantly increased lung cancer risk among MIRLET7BHG (MIRLET7B host gene located at 22q13.31) polymorphisms rs13053856, rs11090910, rs11703832, and rs12170325 heterozygous and homozygous variant allele(s) carriers [pasbestos exposure score was associated with age-, sex-, smoking status- and center-adjusted ORs of 1.34 (95%CI=1.18–1.51), 1.24 (95%CI=1.14–1.35), 1.28 (95%CI=1.17–1.40), and 1.26 (95%CI=1.15–1.38), respectively for lung cancer risk. Conclusion Our findings suggest that MIRLET7BHG polymorphisms may be important predictive markers for asbestos exposure-related lung cancer. Impact To our knowledge, our study is the first report using a systematic genome-wide analysis in combination with detailed asbestos exposure data and replication to evaluate asbestos-associated lung cancer risk. PMID:26199339

  1. Investigation on the influence of time-of-day on benzene metabolic pharmacokinetics by direct breath analysis in mice.

    Science.gov (United States)

    Zhang, Yuling; Sun, Wanyang; Shang, Dewei; Gao, Hao; Zhou, Zhen; Li, Xue

    2017-10-01

    Benzene, well known as a ubiquitous environmental pollutant, can lead to increasing risk of cancer, bone marrow failure as well as other serious diseases. Benzene has been classified as carcinogenic to humans with no recommended safe level of exposure. In this study, the influence of time-of-day on benzene metabolism has been tentatively explored in a mouse model based on direct real-time breath analysis by using membrane inlet single photon ionization time of flight mass spectrometry (MI-SPI-TOFMS). The exhaled breath of eight mice was monitored at a time resolution of less than 20 s after intraperitoneal (I.P.) injection of benzene in the morning, afternoon and evening on different days, and two rounds of experiments were carried out in total. The pharmacokinetic parameters such as total exposure AUC 0-∞ (h ng/mL), peak level C max (ng/mL), time of peak level t max (h), and terminal half-life t 1/2z (h) were calculated and discussed. The values of individual parameter varied greatly among the eight mice, e.g., AUC 0-∞ in the morning of the first round of experiment ranged from 10.66 to 162.17 h ng/mL and the mean ± SD was 103.72 ± 99.72 h ng/mL (n = 8). Significant difference has also been observed between two rounds of experiments, implying the damage in the liver caused by the benzene exposure. However, there is no significant difference among the results from the morning, afternoon and evening for each round of the experiment. In our follow-up study, the influence of time-of-day will be further investigated, in which the metabolites of benzene as well as endogenous metabolites will be considered. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Health risk assessment of ambient air concentrations of benzene, toluene and xylene (BTX) in service station environments.

    Science.gov (United States)

    Edokpolo, Benjamin; Yu, Qiming Jimmy; Connell, Des

    2014-06-18

    A comprehensive evaluation of the adverse health effects of human exposures to BTX from service station emissions was carried out using BTX exposure data from the scientific literature. The data was grouped into different scenarios based on activity, location and occupation and plotted as Cumulative Probability Distributions (CPD) plots. Health risk was evaluated for each scenario using the Hazard Quotient (HQ) at 50% (CEXP50) and 95% (CEXP95) exposure levels. HQ50 and HQ95 > 1 were obtained with benzene in the scenario for service station attendants and mechanics repairing petrol dispensing pumps indicating a possible health risk. The risk was minimized for service stations using vapour recovery systems which greatly reduced the benzene exposure levels. HQ50 and HQ95 service station attendants than any other scenario.

  3. The aromatic volatile organic compounds toluene, benzene and styrene induce COX-2 and prostaglandins in human lung epithelial cells via oxidative stress and p38 MAPK activation.

    Science.gov (United States)

    Mögel, Iljana; Baumann, Sven; Böhme, Alexander; Kohajda, Tibor; von Bergen, Martin; Simon, Jan-Christoph; Lehmann, Irina

    2011-10-28

    Toluene, benzene and styrene are volatile organic compounds (VOCs) widely distributed in the environment. Tobacco smoke, traffic exposure and solvents used for paints, rubber and adhesives are known sources for these compounds. The aim of the present study was to investigate whether toluene, benzene and styrene can induce inflammatory reactions in lung cells and to characterize possible underlying mechanisms. A previous study gave evidence that expression of cyclooxygenase-2 (COX-2) is upregulated following exposure to the aromatic VOC chlorobenzene. Here, we investigated the effects of the aromatics toluene, benzene and styrene on human lung cells, with emphasis on COX-2, the rate-limiting enzyme of the prostaglandin pathway. In addition, we studied the potential role of oxidative stress and p38 MAPK activation in the toluene/benzene/styrene-dependent COX-2 induction. Following exposure to the aromatic compounds the expression level of COX-2 increased markedly. In addition, prostaglandin E(2) (PGE(2)) and prostaglandin F(2α) (PGF(2α)), major products of the COX enzyme, were found to be upregulated in response to toluene, benzene or styrene exposure. Furthermore, we observed an activation of p38 MAPK resulting from aromatic VOC exposure. Treatment of the cells with a specific p38 inhibitor (SB203580) or the antioxidant N-acetylcysteine (NAC) was able to prevent the toluene/benzene/styrene-dependent COX-2 activation, and subsequent increased PGE(2) and PGF(2α) secretion. These results suggest that toluene, benzene and styrene induce production and secretion of PGE(2) and PGF(2α) in lung epithelial cells via p38 MAPK and COX-2 activation in a redox sensitive manner. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  4. A systems biology pipeline identifies new immune and disease related molecular signatures and networks in human cells during microgravity exposure.

    Science.gov (United States)

    Mukhopadhyay, Sayak; Saha, Rohini; Palanisamy, Anbarasi; Ghosh, Madhurima; Biswas, Anupriya; Roy, Saheli; Pal, Arijit; Sarkar, Kathakali; Bagh, Sangram

    2016-05-17

    Microgravity is a prominent health hazard for astronauts, yet we understand little about its effect at the molecular systems level. In this study, we have integrated a set of systems-biology tools and databases and have analysed more than 8000 molecular pathways on published global gene expression datasets of human cells in microgravity. Hundreds of new pathways have been identified with statistical confidence for each dataset and despite the difference in cell types and experiments, around 100 of the new pathways are appeared common across the datasets. They are related to reduced inflammation, autoimmunity, diabetes and asthma. We have identified downregulation of NfκB pathway via Notch1 signalling as new pathway for reduced immunity in microgravity. Induction of few cancer types including liver cancer and leukaemia and increased drug response to cancer in microgravity are also found. Increase in olfactory signal transduction is also identified. Genes, based on their expression pattern, are clustered and mathematically stable clusters are identified. The network mapping of genes within a cluster indicates the plausible functional connections in microgravity. This pipeline gives a new systems level picture of human cells under microgravity, generates testable hypothesis and may help estimating risk and developing medicine for space missions.

  5. Physiological and phylogenetic characterization of a stable benzene-degrading, chlorate-reducing microbial community

    NARCIS (Netherlands)

    Weelink, S.A.B.; Tan, N.C.G.; Broeke, H. ten; Doesburg, W. van; Langenhoff, A.A.M.; Gerritse, J.; Stams, A.J.M.

    2007-01-01

    A stable anoxic enrichment culture was obtained that degraded benzene with chlorate as an electron acceptor. The benzene degradation rate was 1.65 mM benzene per day, which is similar to reported aerobic benzene degradation rates but 20-1650 times higher than reported for anaerobic benzene

  6. Weighted cumulative exposure models helped identify an association between early knee-pain consultations and future knee OA diagnosis.

    Science.gov (United States)

    Yu, Dahai; Peat, George; Bedson, John; Edwards, John J; Turkiewicz, Aleksandra; Jordan, Kelvin P

    2016-08-01

    To establish the association between prior knee-pain consultations and early diagnosis of knee osteoarthritis (OA) by weighted cumulative exposure (WCE) models. Data were from an electronic health care record (EHR) database (Consultations in Primary Care Archive). WCE functions for modeling the cumulative effect of time-varying knee-pain consultations weighted by recency were derived as a predictive tool in a population-based case-control sample and validated in a prospective cohort sample. Two WCE functions ([i] weighting of the importance of past consultations determined a priori; [ii] flexible spline-based estimation) were comprehensively compared with two simpler models ([iii] time since most recent consultation; total number of past consultations) on model goodness of fit, discrimination, and calibration both in derivation and validation phases. People with the most recent and most frequent knee-pain consultations were more likely to have high WCE scores that were associated with increased risk of knee OA diagnosis both in derivation and validation phases. Better model goodness of fit, discrimination, and calibration were observed for flexible spline-based WCE models. WCE functions can be used to model prediagnostic symptoms within routine EHR data and provide novel low-cost predictive tools contributing to early diagnosis. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  7. The resonance energy of benzene: a revisit.

    Science.gov (United States)

    Mo, Yirong

    2009-04-30

    Zielinski and van Lenthe recently extended the block-localized wave function (BLW) method by introducing the resonating BLW (RBLW) method and performed test calculations on hexagonal H(6) and benzene [J. Phys. Chem. A 2008, 112, 13197]. However, the Pauling's resonance energies from their RBLW and ab initio valence bond (VB) calculations were greatly underestimated largely due to the imperfect use of either one-electron orbitals (method = delocal) or resonance structures (method = local). Whereas it has been well recognized that electronic resonance within a molecular system plays a stabilizing role, there are many indirect experimental evidences available to evaluate the resonance energy and, thus, to justify computational results. Here we used the BLW method, which can be regarded as the simplest variant of modern ab initio VB theory, to re-evaluate the resonance energy of benzene at the B3LYP level, following the original definition by Pauling and Wheland, who obtained the resonance energy "by subtracting the actual energy of the molecule in question from that of the most stable contributing structure". The computed vertical resonance energy (or quantum mechanical resonance energy) in benzene is 88.8, 92.2, or 87.9 kcal/mol with the basis sets of 6-31G(d), 6-311+G(d,p), or cc-pVTZ, respectively, while the adiabatic resonance energy (or theoretical resonance energy) is 61.4, 63.2, or 62.4 kcal/mol, exhibiting insignificant basis set dependency for moderate basis sets. In line with predictions, the geometry optimization of the elusive cyclohexatriene (i.e., the Kekule structure) with the BLW method also resulted in carbon-carbon bond lengths (e.g., 1.322 and 1.523 A with the cc-pVTZ basis set) comparable to those in ethylene or ethane.

  8. Benzene-free synthesis of adipic acid.

    Science.gov (United States)

    Niu, Wei; Draths, K M; Frost, J W

    2002-01-01

    Strains of Escherichia coli were constructed and evaluated that synthesized cis,cis-muconic acid from D-glucose under fed-batch fermentor conditions. Chemical hydrogenation of the cis,cis-muconic acid in the resulting fermentation broth has also been examined. Biocatalytic synthesis of adipic acid from glucose eliminates two environmental concerns characteristic of industrial adipic acid manufacture: use of carcinogenic benzene and benzene-derived chemicals as feedstocks and generation of nitrous oxide as a byproduct of a nitric acid catalyzed oxidation. While alternative catalytic syntheses that eliminate the use of nitric acid have been developed, most continue to rely on petroleum-derived benzene as the ultimate feedstock. In this study, E. coli WN1/pWN2.248 was developed that synthesized 36.8 g/L of cis,cis-muconic acid in 22% (mol/mol) yield from glucose after 48 h of culturing under fed-batch fermentor conditions. Optimization of microbial cis,cis-muconic acid synthesis required expression of three enzymes not typically found in E. coli. Two copies of the Klebsiella pneumoniae aroZ gene encoding DHS dehydratase were inserted into the E. coli chromosome, while the K. pneumoniae aroY gene encoding PCA decarboxylase and the Acinetobacter calcoaceticus catA gene encoding catechol 1,2-dioxygenase were expressed from an extrachromosomal plasmid. After fed-batch culturing of WN1/pWN2.248 was complete, the cells were removed from the broth, which was treated with activated charcoal and subsequently filtered to remove soluble protein. Hydrogenation of the resulting solution with 10% Pt on carbon (5% mol/mol) at 3400 kPa of H2 pressure for 2.5 h at ambient temperature afforded a 97% (mol/mol) conversion of cis,cis-muconic acid into adipic acid.

  9. Evaluation of Trans, Trans-Muconic Acid in Urine of Exposed Workers to Benzene in a Cokery Plant

    Directory of Open Access Journals (Sweden)

    M. Rahiminejad

    2006-07-01

    Full Text Available Introduction & Objective: Benzene is a light yellow liquid with aromatic odor and has effects to human body. The main and dangerous health effect of chronic exposure to benzene in workplace is hematopoetic system disease or blood cancer that it's primarily clinical figures are anemia, leucopenia, thrombocytopenia. The objective of this study was evaluation of benzene exposure by analysis of urinary trans, trans-muconic acid (t,t-ma in post shift of workers.Materials & Methods: A case-control study was conducted. The urine samples were collected from 42 workers exposed to benzene at a cokery plant and it’s by –product refinery site and 40 non exposed villagers from rural areas without nearby factories. The t,t-ma was extracted from urine by solid phase extraction (SPE and analyzed via high performance liquid chromatography (HPLC. The urinary creatinine level was measured by Kone – Pro autoanalyzer . Results: The mean urinary t,t – ma level was 3.33 mg/g creatinine for exposed workers and 0.1007 mg/g creatinine for non exposed workers. The urinary levels in exposed group differed among workplaces, and were higher for subjects that worked in cokery plant ( cokery plant, 3.68 mg / g creatinine; its by product refinery site, 0.64 mg / g creatinine.Conclusion: The results showed that the mean level of urinary t,t-ma was about 6 to 7 times more than biological exposure index; thus, there is a high risk of hematopoetic damage and other adverse effects in these workers. We suggest that the company must decrease benzene exposure via engineering and management controls to lower than threshold limit value.

  10. Hombres Sanos: exposure and response to a social marketing HIV prevention campaign targeting heterosexually identified Latino men who have sex with men and women.

    Science.gov (United States)

    Martínez-Donate, Ana P; Zellner, Jennifer A; Fernández-Cerdeño, Araceli; Sañudo, Fernando; Hovell, Melbourne F; Sipan, Carol L; Engelberg, Moshe; Ji, Ming

    2009-10-01

    This study examined the reach and impact of a social marketing intervention to reduce HIV risk among heterosexually identified (HI) Latino men who have sex with men and women (MSMW). Repeated cross-sectional intercept surveys were conducted in selected community venues during and after the campaign with 1,137 HI Latino men. Of them, 6% were classified as HI Latino MSMW. On average, 85.9% of the heterosexual respondents and 86.8% of the HI MSMW subsample reported exposure to the campaign. Responses to the campaign included having made an appointment for a male health exam that included HIV testing and using condoms. Campaign exposure was significantly associated with HIV testing behavior and intentions and with knowledge of where to get tested. The campaign reached its underserved target audience and stimulated preventive behaviors. Social marketing represents a promising approach for HIV prevention among HI Latinos, in general, and HI Latino MSMW, in particular.

  11. Benzene and cyclohexane separation using 1-butyl-3-methylimidazolium thiocyanate

    Science.gov (United States)

    Gonfa, Girma; Ismail, Marhaina; Bustam, Mohamad Azmi

    2017-09-01

    Cyclohexane is mainly produced by catalytic hydrogenation of benzene. Removal of unreacted benzene from the product stream is very important in this process. However, due to their close boiling points and azeotrope formation, it is very difficult to separate cyclohexane and benzene by conventional distillation. Currently, special separation processes such as processes extractive distillation is commercially used for this separation. However, this extractive distillation suffers from process complexity and higher energy consumption due to their low extractive selectivity of molecular entrainers used. The aim of the present work is to investigate the applicability of ionic liquids as entrainer in extractive distillation of benzene and cyclohexane mixture. In this study, we investigated 1-butyl-3-methylimidazolium thiocyanate ([BMIM][SCN]) ionic liquid for separation of benzene and cyclohexane by measuring the Vapor Liquid Equilibrium data of the two components in the presence of the ionic liquid. As green and potential environmentally friendly solvents, ionic liquids have attracted increasing attention as alternative conventional entrainers in extractive distillation. Isothermal Vapor Liquid Equilibrium for the benzene + cyclohexane + [BMIM][SCN] ternary system was obtained at 353.15 K using a Head Space Gas Chromatography. The addition of [BMIM][SCN] breaks the benzene-cyclohexane azeotrope and increased the relative volatility cyclohexane to benzene in the mixture. The effect of [BMIM][SCN] on the relative volatility cyclohexane to benzene was studied at various benzene and cyclohexane compositions and solvent to feed ratios. The performance of [BMIM][SCN] was compared with typical conventional solvents, dimethylformamide (DMF) and dimethylsulfoxide (DMSO). The results show that the relative volatility of cyclohexane to benzene in the presence of [BMIM][SCN] is higher compared that of DMSO and DMF.

  12. A factor analysis of global GABAergic gene expression in human brain identifies specificity in response to chronic alcohol and cocaine exposure.

    Science.gov (United States)

    Enoch, Mary-Anne; Baghal, Basel; Yuan, Qiaoping; Goldman, David

    2013-01-01

    Although expression patterns of GABAergic genes in rodent brain have largely been elucidated, no comprehensive studies have been performed in human brain. The purpose of this study was to identify global patterns of GABAergic gene expression in healthy adults, including trans and cis effects in the GABAA gene clusters, before determining the effects of chronic alcohol and cocaine exposure on gene expression in the hippocampus. RNA-Seq data from 'BrainSpan' was obtained across 16 brain regions from postmortem samples from nine adults. A factor analysis was performed on global expression of 21 GABAergic pathway genes. Factor specificity for response to chronic alcohol/cocaine exposure was subsequently determined from the analysis of RNA-Seq data from postmortem hippocampus of eight alcoholics, eight cocaine addicts and eight controls. Six gene expression factors were identified. Most genes loaded (≥0.5) onto one factor; six genes loaded onto two. The largest factor (0.30 variance) included the chromosome 5 gene cluster that encodes the most common GABAA receptor, α1β2γ2, and genes encoding the α3β3γ2 receptor. Genes within this factor were largely unresponsive to chronic alcohol/cocaine exposure. In contrast, the chromosome 4 gene cluster factor (0.14 variance) encoding the α2β1γ1 receptor was influenced by chronic alcohol/cocaine exposure. Two other factors (0.17 and 0.06 variance) showed expression changes in alcoholics/cocaine addicts; these factors included genes involved in GABA synthesis and synaptic transport. Finally there were two factors that included genes with exceptionally low (0.10 variance) and high (0.09 variance) expression in the cerebellum; the former factor was unaffected by alcohol/cocaine exposure. This study has shown that there appears to be specificity of GABAergic gene groups, defined by covariation in expression, for response to chronic alcohol/cocaine exposure. These findings might have implications for combating stress

  13. Use of medaka (Oryzias latipes) as a model teleost to identify reproductive endpoints indicative of exposure to endocrine disrupting chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Papoulias, D.M.; Tillitt, D.; Jones, S. [National Biological Service, Columbia, MO (United States); Noltie, D. [Univ. of Missouri, Columbia, MO (United States)

    1995-12-31

    The purpose of this research is to identify effects of endocrine disrupting chemicals on the reproductive system of fish at various stages of sexual differentiation and development. The model teleost used was the d-rR strain of medaka (Oryzias latipes) which has a heritable sex-linked color gene. In medaka, sex differences are first detected at the cellular level at hatch. In males, the mitotic activity of the primordial germ cells (PGC) is arrested while the PGCs of the females continue to divide. The germ cells of the gonochoristic medaka have been demonstrated to be totipotent with respective to gonia production. Because endogenous sex steroid hormones are believed to regulate this early process of sexual differentiation, the authors have hypothesized that mitotic activity in males and females exposed to endocrine disrupting chemicals will be different than unexposed individuals. Results are presented for tests conducted by injecting medaka eggs within 36 hours post-hatch with 3 doses of 2,3,7,8-TCDD (nominally 2.3, 1.3, 0.2 pg/embryo), a known anti-estrogen, dissolved in triolein.

  14. In situ synthesis of silver benzene-dithiolate hybrid films

    Energy Technology Data Exchange (ETDEWEB)

    Brenier, Roger, E-mail: roger.brenier@univ-lyon1.fr [Institut Lumière Matière, UMR 5306, Université Lyon 1-CNRS, Université de Lyon, Domaine Scientifique de La Doua, Batiment Kastler, 10 rue Ada Byron, 69622 Villeurbanne, Cedex (France); Piednoir, Agnès, E-mail: agnes.piednoir@univ-lyon1.fr [Institut Lumière Matière, UMR 5306, Université Lyon 1-CNRS, Université de Lyon, Domaine Scientifique de La Doua, Batiment Kastler, 10 rue Ada Byron, 69622 Villeurbanne, Cedex (France); Bertorelle, Franck, E-mail: franck.bertorelle@univ-lyon1.fr [Institut Lumière Matière, UMR 5306, Université Lyon 1-CNRS, Université de Lyon, Domaine Scientifique de La Doua, Batiment Kastler, 10 rue Ada Byron, 69622 Villeurbanne, Cedex (France); Penuelas, José, E-mail: jose.penuelas@ec-lyon.fr [Université de Lyon, Institut des Nanotechnologies de Lyon, Ecole Centrale de Lyon, CNRS, UMR 5270, 36 rue Guy de Collongues, F69134 Ecully (France); Grenet, Geneviève, E-mail: genevieve.grenet@ec-lyon.fr [Université de Lyon, Institut des Nanotechnologies de Lyon, Ecole Centrale de Lyon, CNRS, UMR 5270, 36 rue Guy de Collongues, F69134 Ecully (France)

    2016-02-01

    In this article, a method for in situ synthesis of silver benzene-dithiolate hybrid films is presented. Silver nanoparticles, generated on ZrO{sub 2} films, are transformed into silver benzene 1,4-dithiolate or, partially, into silver benzene 1,2-dithiolate after sample immersion in the corresponding thiol solutions. These transformations occur at room temperature owing to the catalytic action of ZrO{sub 2}. It is also shown that TiO{sub 2} in place of ZrO{sub 2} is very efficient, both for the catalytic generation of silver nanoparticles and for their further transformation in benzene 1,4-dithiolate compound. This latter semiconductor has an optical bandgap of about 3 eV and the film is made of touching nanoparticles in an amorphous state. Our work has potential applications in the electronic and photovoltaic fields. - Highlights: • A method for in situ synthesis of silver benzene-dithiolate hybrid semiconductor films is presented. • Silver nanoparticles are, first, generated on ZrO{sub 2} or on TiO{sub 2} coated silica substrates. • The samples are immersed in benzene dithiol solution for two days at room temperature. • During the immersion, the silver nanoparticles are transformed into silver benzene dithiolate. • The silver benzene dithiolate film is made of amorphous nanoparticles with a banbgap of 3 eV.

  15. The excited state antiaromatic benzene ring: a molecular Mr Hyde?

    Science.gov (United States)

    Papadakis, Raffaello; Ottosson, Henrik

    2015-09-21

    The antiaromatic character of benzene in its first ππ* excited triplet state (T1) was deduced more than four decades ago by Baird using perturbation molecular orbital (PMO) theory [J. Am. Chem. Soc. 1972, 94, 4941], and since then it has been confirmed through a range of high-level quantum chemical calculations. With focus on benzene we now first review theoretical and computational studies that examine and confirm Baird's rule on reversal in the electron count for aromaticity and antiaromaticity of annulenes in their lowest triplet states as compared to Hückel's rule for the ground state (S0). We also note that the rule according to quantum chemical calculations can be extended to the lowest singlet excited state (S1) of benzene. Importantly, Baird, as well as Aihara [Bull. Chem. Soc. Jpn. 1978, 51, 1788], early put forth that the destabilization and excited state antiaromaticity of the benzene ring should be reflected in its photochemical reactivity, yet, today these conclusions are often overlooked. Thus, in the second part of the article we review photochemical reactions of a series of benzene derivatives that to various extents should stem from the excited state antiaromatic character of the benzene ring. We argue that benzene can be viewed as a molecular "Dr Jekyll and Mr Hyde" with its largely unknown excited state antiaromaticity representing its "Mr Hyde" character. The recognition of the "Jekyll and Hyde" split personality feature of the benzene ring can likely be useful in a range of different areas.

  16. Small-angle neutron scattering studies of sodium butyl benzene ...

    Indian Academy of Sciences (India)

    shape and size of the aggregates of sodium n-butyl benzene sulfonate in aqueous solutions. To the best of our knowledge this is the first SANS report on the aggre- gation behaviour of a hydrotrope in aqueous solutions. 2. Materials and methods n-Butyl benzene, procured from Herdilia Chemicals, Mumbai, was sulfonated ...

  17. Nonthermal plasma assisted photocatalytic oxidation of dilute benzene

    Indian Academy of Sciences (India)

    to utilize the UV light for photocatalytic decomposition of chlorinated VOCs.23. Benzene, a commonly used industrial solvent, whose abatement under dilute concentrations (<1000 ppm) may not be economical by conventional techniques. The present study was aimed at the total oxidation of dilute benzene in a DBD reactor.

  18. Evidence that humans metabolize benzene via two pathways.

    NARCIS (Netherlands)

    Rappaport, S.M.; Kim, S.; Lan, Q.; Vermeulen, R.C.H.; Waidyanatha, S.; Zhang, L.; Li, G.; Yin, S.; Hayes, R.B.; Rothman, N.; Smith, M.T.

    2009-01-01

    BACKGROUND: Recent evidence has shown that humans metabolize benzene more efficiently at environmental air concentrations than at concentrations > 1 ppm. This led us to speculate that an unidentified metabolic pathway was mainly responsible for benzene metabolism at ambient levels. OBJECTIVE: We

  19. Benzene degradation coupled with chlorate reduction in soil column study

    NARCIS (Netherlands)

    Tan, N.C.G.; Doesburg, van W.C.J.; Langenhoff, A.A.M.; Stams, A.J.M.

    2006-01-01

    Perchlorate and chlorate are electron acceptors that during reduction result in the formation of molecular oxygen. The produced oxygen can be used for activation of anaerobic persistent pollutants, like benzene. In this study chlorate was tested as potential electron acceptor to stimulate benzene

  20. An evidence-based analysis of epidemiologic associations between lymphatic and hematopoietic cancers and occupational exposure to gasoline.

    Science.gov (United States)

    Keenan, J J; Gaffney, S; Gross, S A; Ronk, C J; Paustenbach, D J; Galbraith, D; Kerger, B D

    2013-10-01

    The presence of benzene in motor gasoline has been a health concern for potential increased risk of acute myelogenous leukemia and perhaps other lymphatic/hematopoietic cancers for approximately 40 years. Because of the widespread and increasing use of gasoline by consumers and the high exposure potential of occupational cohorts, a thorough understanding of this issue is important. The current study utilizes an evidence-based approach to examine whether or not the available epidemiologic studies demonstrate a strong and consistent association between occupational exposure to gasoline and lymphatic/hematopoietic cancers. Among 67 epidemiologic studies initially identified, 54 were ranked according to specific criteria relating to the relevance and robustness of each study for answering the research question. The 30 highest-ranked studies were sorted into three tiers of evidence and were analyzed for strength, specificity, consistency, temporality, dose-response trends and coherence. Meta statistics were also calculated for each general and specific lymphatic/hematopoietic cancer category with adequate data. The evidence-based analysis did not confirm any strong and consistent association between occupational exposure to gasoline and lymphatic/hematopoietic cancers based on the epidemiologic studies available to date. These epidemiologic findings, combined with the evidence showing relatively low occupational benzene vapor exposures associated with gasoline formulations during the last three decades, suggest that current motor gasoline formulations are not associated with increased lymphatic/hematopoietic cancer risks related to benzene.

  1. Catalytic conversion of alcohols to hydrocarbons with low benzene content

    Energy Technology Data Exchange (ETDEWEB)

    Narula, Chaitanya K.; Davison, Brian H.; Keller, Martin

    2016-03-08

    A method for converting an alcohol to a hydrocarbon fraction having a lowered benzene content, the method comprising: converting said alcohol to a hydrocarbon fraction by contacting said alcohol, under conditions suitable for converting said alcohol to said hydrocarbon fraction, with a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon fraction, and contacting said hydrocarbon fraction with a benzene alkylation catalyst, under conditions suitable for alkylating benzene, to form alkylated benzene product in said hydrocarbon fraction. Also described is a catalyst composition useful in the method, comprising a mixture of (i) a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon, and (ii) a benzene alkylation catalyst, in which (i) and (ii) may be in a mixed or separated state. A reactor for housing the catalyst and conducting the reaction is also described.

  2. Catalytic conversion of alcohols to hydrocarbons with low benzene content

    Energy Technology Data Exchange (ETDEWEB)

    Narula, Chaitanya K.; Davison, Brian H.; Keller, Martin

    2016-09-06

    A method for converting an alcohol to a hydrocarbon fraction having a lowered benzene content, the method comprising: converting said alcohol to a hydrocarbon fraction by contacting said alcohol, under conditions suitable for converting said alcohol to said hydrocarbon fraction, with a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon fraction, and contacting said hydrocarbon fraction with a benzene alkylation catalyst, under conditions suitable for alkylating benzene, to form alkylated benzene product in said hydrocarbon fraction. Also described is a catalyst composition useful in the method, comprising a mixture of (i) a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon, and (ii) a benzene alkylation catalyst, in which (i) and (ii) may be in a mixed or separated state. A reactor for housing the catalyst and conducting the reaction is also described.

  3. Influence of benzene emission from motorcycle on Bangkok air quality

    Science.gov (United States)

    Leong, Shing Tet; Muttamara, S.; Laortanakul, Preecha

    This study investigated the influence of benzene concentration from motorcycle exhaust emissions on ambient air quality in Bangkok Metropolitan Region (BMR). Measurement of benzene concentration in exhaust emissions is performed on a standard test driving cycle through which each motorcycle to be tested is driven. The test result revealed that average benzene concentrations in exhaust emission for the test motorcycles ranged from 3.02 to 109.68 mg/m 3. The finding also indicated that two-stroke motorcycles emitted five times more benzene than that of four-stroke motorcycles. Four air monitoring sites were strategically established to determine the relationship between average benzene concentrations with different traffic configurations in each traffic zone of BMR during peak/non-peak hours, day/night times and weekday/weekend. The shape of the curve for benzene level usually shows two peaks corresponding to the morning and evening traffic rush or commuter rush hours. The finding shows that the mean concentrations for benzene in all monitoring stations in the ambient air for peak hours (07:00-09:00 and 16:00-18:00 h) ranged from 15.1 to 42.4 μg/m 3. For non-peak hour (11:30-15:00 h), benzene levels were found in the range 16.3-30.9 μg/m 3. It is observed that higher levels of benzene are found among roadside stations with slow moving traffic while lower levels are found among roadside stations with fast traffic movement. Additional factors such as temperature, wind speed, rainfall, etc. are also considered in this study to determine the relationship between traffic conditions and ambient benzene levels.

  4. Competitive Nitration of Benzene-Fluorobenzene and Benzene-Toluene Mixtures: Orientation and Reactivity Studies Using HPLC

    Science.gov (United States)

    Blankespoor, Ronald L.; Hogendoorn, Stephanie; Pearson, Andrea

    2007-01-01

    The reactivity and orientation effects of a substituent are analyzed by using HPLC to determine the competitive nitration of the benzene-toluene and benzene-fluorobenzene mixtures. The results have shown that HPLC is an excellent instrumental method to use in analyzing these mixtures.

  5. Implications of Thermal Annealing on the Benzene Vapor Sensing Behavior of PEVA-Graphene Nanocomposite Threads.

    Science.gov (United States)

    Patel, Sanjay V; Cemalovic, Sabina; Tolley, William K; Hobson, Stephen T; Anderson, Ryan; Fruhberger, Bernd

    2018-02-14

    The effect of thermal treatments, on the benzene vapor sensitivity of polyethylene (co-)vinylacetate (PEVA)/graphene nanocomposite threads, used as chemiresistive sensors, was investigated using DC resistance measurements, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). These flexible threads are being developed as low-cost, easy-to-measure chemical sensors that can be incorporated into smart clothing or disposable sensing patches. Chemiresistive threads were solution-cast or extruded from PEVA and vapor in dry air. In addition, annealing increased the speed of response and recovery upon exposure to and removal of benzene vapor. DSC results showed that the presence of graphene raises the freezing point, and may allow greater crystallinity, in the nanocomposite after annealing. SEM images confirm increased surface roughness/area, which may account for the increase response speed after annealing. Benzene vapor detection at 5 ppm is demonstrated with limits of detection estimated to be as low as 1.5 ppm, reflecting an order of magnitude improvement over unannealed threads.

  6. Effect of benzene and ethylbenzene on the transcription of methyl-tert-butyl ether degradation genes of Methylibium petroleiphilum PM1.

    Science.gov (United States)

    Joshi, Geetika; Schmidt, Radomir; Scow, Kate M; Denison, Michael S; Hristova, Krassimira R

    2016-09-01

    Methyl-tert-butyl ether (MTBE) and its degradation by-product, tert-butyl alcohol (TBA), are widespread contaminants detected frequently in groundwater in California. Since MTBE was used as a fuel oxygenate for almost two decades, leaking underground fuel storage tanks are an important source of contamination. Gasoline components such as BTEX (benzene, toluene, ethylbenzene and xylenes) are often present in mixtures with MTBE and TBA. Investigations of interactions between BTEX and MTBE degradation have not yielded consistent trends, and the molecular mechanisms of BTEX compounds' impact on MTBE degradation are not well understood. We investigated trends in transcription of biodegradation genes in the MTBE-degrading bacterium, Methylibium petroleiphilum PM1 upon exposure to MTBE, TBA, ethylbenzene and benzene as individual compounds or in mixtures. We designed real-time quantitative PCR assays to target functional genes of strain PM1 and provide evidence for induction of genes mdpA (MTBE monooxygenase), mdpJ (TBA hydroxylase) and bmoA (benzene monooxygenase) in response to MTBE, TBA and benzene, respectively. Delayed induction of mdpA and mdpJ transcription occurred with mixtures of benzene and MTBE or TBA, respectively. bmoA transcription was similar in the presence of MTBE or TBA with benzene as in their absence. Our results also indicate that ethylbenzene, previously proposed as an inhibitor of MTBE degradation in some bacteria, inhibits transcription of mdpA, mdpJ and bmoAgenes in strain PM1.

  7. Indoor Residential Chemical Exposures as Risk Factors for Asthmaand Allergy in Infants and Children: a Review

    Energy Technology Data Exchange (ETDEWEB)

    Mendell, M.J.

    2006-03-01

    Most research into effects of residential indoor air exposures on asthma and allergies has focused on exposures to biologic allergens, moisture and mold, endotoxin, or combustion byproducts. This paper briefly reviews reported findings on associations of asthma or allergy in infants or children with risk factors related to indoor chemical emissions from residential materials or surface coatings. Associations, some strong (e.g., odds ratios up to 13), were reported. The most frequently identified risk factors were formaldehyde, aromatic organic compounds such as toluene and benzene, plastic materials and plasticizers, and recent painting. Exposures and consequent effects from indoor sources may be exacerbated by decreased ventilation. Identified risk factors may be proxies for correlated exposures. Findings suggest the frequent occurrence of important but preventable effects on asthma and allergy in infants and children worldwide from modern residential building materials and coatings.

  8. Measurement of BTEX (benzene, toluene, ethybenzene, and xylene) levels at urban and semirural areas of Algiers City using passive air samplers.

    Science.gov (United States)

    Kerchich, Yacine; Kerbachi, Rabah

    2012-12-01

    The study presents the levels of air pollution by aromatic organic compounds BTEX (benzene, toluene, ethylbenzene, o-, m-, and p-xylenes) in the city of Algiers. The sampling was carried out using Radiello passive sampler. Three sampling campaigns were carried out in roadside, tunnel, urban background, and semirural sites in Algiers. In order to determine the diurnal mean levels of air pollution by BTEX to which people are exposed, a modified passive sampler was used for the first time. In addition, monitoring of pollution inside vehicles was also made. In the spring of 2009, more than 27 samplings were carried out. In the background and road traffic sites the Radiello sampler was exposed for 7 days, whereas the time exposure was reduced to 1 day in the case of the vehicle as well as the tunnel. The results indicate that average benzene concentrations in the roadside and inside vehicle exceed largely the limit value of 5 microg m(-3) established by the European Community (EC). On the other hand, it has been noticed that the concentration levels of other BTEX are relatively high. Also, in order to identify the origin of emission sources, ratios and correlations between the BTEX species have been highlighted. This study shows that road traffic remains the main source of many local emission in Algiers. The vehicle fleet in Algeria is growing rapidly since the 1990s following economic growth and is responsible for the increasing air pollution in large cities. Because there are no data collection of BTEX carried out by national air quality network, all environmental and transportation policies are based on European emissions standards, but national emission standards are currently not in place. This work will contribute to the analysis of real emissions of BTEX in Algiers, for the development of management and for assessment of population exposure variation depending on the location in the city of Algiers.

  9. Uptake, distribution, and depuration of 14C-benzene in northern anchovy, Engraulis mordax, and striped bass, Morone saxatilis

    International Nuclear Information System (INIS)

    Korn, S.; Hirsch, N.; Struhsaker, J.W.

    1976-01-01

    The uptake, distribution, and depuration of water-soluble, monocyclic hydrocarbon contained in petroleum and refined products was studied in two species of marine fish. Mature northern anchovy, Engraulis mordax, and juvenile striped bass, Morone saxatilis, were exposed to sublethal concentrations of O 14 -benzene for 48 h. Residues in tissues exhibiting a high lipid content or representing apparent major metabolic sites were measured during the exposure and afterwards when the fish were transferred to clean seawater. Fish exhibited a rapid uptake over a wide range of benzene concentrations in the water column. Accumulation in anchovy was considerably greater than in striped bass. Results indicate that the pathway of hydrocarbons through the liver, gallbladder, intestines, and colon is a major depuration route. Residues were depurated rapidly after cessation of exposure; in striped bass tissues most residues were undetectable by 7 days

  10. 40 CFR 80.1295 - How are gasoline benzene credits used?

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false How are gasoline benzene credits used... PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Benzene Averaging, Banking and Trading (abt) Program § 80.1295 How are gasoline benzene credits used? (a) Credit use. (1) Gasoline benzene...

  11. 40 CFR 80.1356 - What are the attest engagement requirements for gasoline benzene compliance?

    Science.gov (United States)

    2010-07-01

    ... requirements for gasoline benzene compliance? 80.1356 Section 80.1356 Protection of Environment ENVIRONMENTAL... Benzene Attest Engagements § 80.1356 What are the attest engagement requirements for gasoline benzene... that contain gasoline benzene and gasoline volume information. (2) Agree the yearly volumes of gasoline...

  12. Electronic structure of benzene adsorbed on Ni and Cu surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Weinelt, M.; Nilsson, A.; Wassdahl, N. [Uppsala Univ. (Sweden)] [and others

    1997-04-01

    Benzene has for a long time served as a prototype adsorption system of large molecules. It adsorbs with the molecular plane parallel to the surface. The bonding of benzene to a transition metal is typically viewed to involve the {pi} system. Benzene adsorbs weakly on Cu and strongly on Ni. It is interesting to study how the adsorption strength is reflected in the electronic structure of the adsorbate-substrate complex. The authors have used X-ray Emission (XE) and X-ray Absorption (XA) spectroscopies to selectively study the electronic states localized on the adsorbed benzene molecule. Using XES the occupied states can be studies and with XAS the unoccupied states. The authors have used beamline 8.0 and the Swedish endstation equipped with a grazing incidence x-ray spectrometer and a partial yield absorption detector. The resolution in the XES and XAS were 0.5 eV and 0.05 eV, respectively.

  13. Positronium quenching in liquid and solid octanol and benzene

    DEFF Research Database (Denmark)

    Shantarovich, V.P.; Mogensen, O.E.; Goldanskii, V.I.

    1970-01-01

    The lifetimes of orthopositronium in several solutions in liquid and solid octanol and benzene have been measured. The Ps-quenching constant was found to be two to thirty times higher in the solid than in the liquid phase....

  14. Toxicity of substituted benzene derivatives to four chemolithotrophic ...

    African Journals Online (AJOL)

    The toxicity of benzene, hydroxylbenzene (phenol), chlorobenzene, methylbenzene (toluene) and dimethylbenzene (xylene) to four chemolithotrophic bacteria (Nitrosomonas, Nitrobacter, Thiobacillus and Leptothrix isolated from the New Calabar River water was investigated. The static method for acute toxicity assessment ...

  15. Vacuum ultraviolet photoabsorption spectroscopy of crystalline and amorphous benzene

    DEFF Research Database (Denmark)

    Dawes, Anita; Pascual, Natalia; Hoffmann, Soren V.

    2017-01-01

    We present the first high resolution vacuum ultraviolet photoabsorption study of amorphous benzene with com parisons to annealed crystalline benzene and the gas phase. Vapour deposited benzene layers w ere grow n at 25 K and annealed to 90 K under conditions pertinent to interstellaricy dust grains...... and icy planetary bodies in our solar system. Three single t-single t electronic transitions in solid benzene correspond to the B-1(2u), B-1(1u) and E-1(1u) states, redshifted by 0.05, 0.25 and 0.51 eV respectively with respect to the gas phase. The symmetry forbidden B-1(2u)...

  16. Intrinsic and enhanced biodegradation of benzene in strongly reduced aquifers

    NARCIS (Netherlands)

    Heiningen, W.N.M. van; Rijnaarts, H.H.M; Langenhoff, A.A.M.

    1999-01-01

    Laboratory microcosm studies were performed to examine intrinsic and enhanced benzene bioremediation using five different sediment and groundwater samples from three deeply anaerobic aquifers sited in northern Netherlands. The influence of addition of nitrate, sulfate, limited amounts of oxygen, and

  17. Measurements of benzene and formaldehyde in a medium sized urban environment. Indoor/outdoor health risk implications on special population groups.

    Science.gov (United States)

    Pilidis, Georgios A; Karakitsios, Spyros P; Kassomenos, Pavlos A; Kazos, Elias A; Stalikas, Constantine D

    2009-03-01

    In the present study, the results of a measurement campaign aiming to assess cancer risk among two special groups of population: policemen and laboratory technicians exposed to the toxic substances, benzene and formaldehyde are presented. The exposure is compared to general population risk. The results show that policemen working outdoor (traffic regulation, patrol on foot or in vehicles, etc.) are exposed at a significantly higher benzene concentration (3-5 times) than the general population, while the exposure to carbonyls is in general lower. The laboratory technicians appear to be highly exposed to formaldehyde while no significant variation of benzene exposure in comparison to the general population is recorded. The assessment revealed that laboratory technicians and policemen run a 20% and 1% higher cancer risk respectively compared to the general population. Indoor working place air quality is more significant in assessing cancer risk in these two categories of professionals, due to the higher Inhalation Unit Risk (IUR) of formaldehyde compared to benzene. Since the origin of the danger to laboratory technicians is clear (use of chemicals necessary for the experiments), in policemen the presence of carbonyls in indoor air concentrations due to smoking or used materials constitute a danger equal to the exposure to traffic originated air pollutants.

  18. Modeling the formation and reactions of benzene metabolites.

    Science.gov (United States)

    Golding, Bernard T; Barnes, Martine L; Bleasdale, Christine; Henderson, Alistair P; Jiang, Dong; Li, Xin; Mutlu, Esra; Petty, Hannah J; Sadeghi, Majid M

    2010-03-19

    One or more of the muconaldehyde isomers is a putative product of benzene metabolism. As muconaldehydes are highly reactive dienals and potentially mutagenic they might be relevant to the carcinogenicity of benzene. Muconaldehydes may be derived through the action of a cytochrome P450 mono-oxygenase on benzene oxide-oxepin, which are established metabolites of benzene. Oxidation of benzene oxide-oxepin either by the one-electron oxidant cerium(IV) ammonium nitrate (CAN) or by iron(III) tris(1,10-phenanthroline) hexafluorophosphate in acetone at -78 degrees C or acetonitrile at -40 degrees C gave (E,Z)-muconaldehyde, which was a single diastereoisomer according to analysis by (1)H NMR spectroscopy. Reaction of toluene-1,2-oxide/2-methyloxepin with CAN gave (2E,4Z)-6-oxo-hepta-2,4-dienal. Similarly, the action of CAN on 1,6-dimethylbenzene oxide-2,7-dimethyloxepin gave (3Z,5E)-octa-3,5-diene-2,7-dione. In vivo, benzene oxide-oxepin could suffer one-electron oxidation by cytochrome P450 mono-oxygenase giving (E,Z)-muconaldehyde. The observations presented may be relevant to the toxicology of benzene oxide-oxepin and other arene oxide-oxepins as we have previously shown that (E,Z)-muconaldehyde, analogously to (Z,Z)-muconaldehyde, affords pyrrole adducts with the exocyclic amino groups of the DNA bases adenine and guanine. Independent of their possible toxicological significance, the experiments described provide preparatively useful routes to (E,Z)-muconaldehyde and its congeners. Methods are also described for the trapping and analysis of reactive benzene metabolites, e.g. using the Diels-Alder reaction with the dienophile 4-phenyl-1,2,4-triazoline-3,5-dione to trap arene oxides and with the diene 1,3-diphenylisobenzofuran to trap enals. Copyright (c) 2010 Elsevier Ireland Ltd. All rights reserved.

  19. Metabolism of Benzene, Toluene, and Xylene Hydrocarbons in Soil†

    OpenAIRE

    Tsao, C.-W.; Song, H.-G.; Bartha, R.

    1998-01-01

    Enrichment cultures obtained from soil exposed to benzene, toluene, and xylene (BTX) mineralized benzene and toluene but cometabolized only xylene isomers, forming polymeric residues. This observation prompted us to investigate the metabolism of 14C-labeled BTX hydrocarbons in soil, either individually or as mixtures. BTX-supplemented soil was incubated aerobically for up to 4 weeks in a sealed system that automatically replenished any O2 consumed. The decrease in solvent vapors and the produ...

  20. The active and passive sampling of benzene, toluene, ethyl benzene and xylenes compounds using the inside needle capillary adsorption trap device.

    Science.gov (United States)

    Shojania, S; Oleschuk, R D; McComb, M E; Gesser, H D; Chow, A

    1999-08-23

    A new and simple method of solventless extraction of volatile organic compounds (VOCs) from air is presented. The sampling device has an adsorbing carbon coating on the interior surface of a hollow needle, and is called the inside needle capillary adsorption trap (INCAT). This paper describes a study of the reproducibility in the preparation and sampling of the INCAT device. In addition, this paper examines the effects of sample volume in active sampling and exposure time in passive sampling on the analyte adsorption. Analysis was achieved by sampling the air from an environmental chamber doped with benzene, toluene, ethyl benzene and xylenes (BTEX) compounds. Initial rates of adsorption were found to vary among the different compounds, but ranged from 0.0099 to 0.016 nmol h(-1) for passive sampling and from 2.2 to 10 nmol h(-1) for active sampling. Analysis was done by thermal desorption of the adsorbed compounds directly into a gas chromatograph injection port. Quantification of the analysis was done by comparison to actively sampled activated carbon solid phase extraction (SPE) measurements.

  1. Proteomic screening identifies calreticulin as a miR-27a direct target repressing MHC class I cell surface exposure in colorectal cancer.

    Science.gov (United States)

    Colangelo, T; Polcaro, G; Ziccardi, P; Pucci, B; Muccillo, L; Galgani, M; Fucci, A; Milone, M R; Budillon, A; Santopaolo, M; Votino, C; Pancione, M; Piepoli, A; Mazzoccoli, G; Binaschi, M; Bigioni, M; Maggi, C A; Fassan, M; Laudanna, C; Matarese, G; Sabatino, L; Colantuoni, V

    2016-02-25

    Impairment of the immune response and aberrant expression of microRNAs are emerging hallmarks of tumour initiation/progression, in addition to driver gene mutations and epigenetic modifications. We performed a preliminary survey of independent adenoma and colorectal cancer (CRC) miRnoma data sets and, among the most dysregulated miRNAs, we selected miR-27a and disclosed that it is already upregulated in adenoma and further increases during the evolution to adenocarcinoma. To identify novel genes and pathways regulated by this miRNA, we employed a differential 2DE-DIGE proteome analysis. We showed that miR-27a modulates a group of proteins involved in MHC class I cell surface exposure and, mechanistically, demonstrated that calreticulin is a miR-27a direct target responsible for most downstream effects in epistasis experiments. In vitro miR-27a affected cell proliferation and angiogenesis; mouse xenografts of human CRC cell lines expressing different miR-27a levels confirmed the protein variations and recapitulated the cell growth and apoptosis effects. In vivo miR-27a inversely correlated with MHC class I molecules and calreticulin expression, CD8(+) T cells infiltration and cytotoxic activity (LAMP-1 exposure and perforin release). Tumours with high miR-27a, low calreticulin and CD8(+) T cells' infiltration were associated with distant metastasis and poor prognosis. Our data demonstrate that miR-27a acts as an oncomiRNA, represses MHC class I expression through calreticulin downregulation and affects tumour progression. These results may pave the way for better diagnosis, patient stratification and novel therapeutic approaches.

  2. Exposition by inhalation to the benzene, toluene, ethyl-benzene and xylenes (BTEX) in the air. Sources, measures and concentrations

    International Nuclear Information System (INIS)

    Del Gratta, F.; Durif, M.; Fagault, Y.; Zdanevitch, I.

    2004-12-01

    This document presents the main techniques today available to characterize the benzene, toluene, ethyl-benzene and xylene (BTEX) concentrations in the air for different contexts: urban and rural areas or around industrial installations but also indoor and occupational area. It provides information to guide laboratories and research departments. A synthesis gives also the main emissions sources of these compounds as reference concentrations measured in different environments. (A.L.B.)

  3. XUV-induced reactions in benzene on sub-10 fs timescale: nonadiabatic relaxation and proton migration.

    Science.gov (United States)

    Galbraith, M C E; Smeenk, C T L; Reitsma, G; Marciniak, A; Despré, V; Mikosch, J; Zhavoronkov, N; Vrakking, M J J; Kornilov, O; Lépine, F

    2017-08-02

    Unraveling ultrafast dynamical processes in highly excited molecular species has an impact on our understanding of chemical processes such as combustion or the chemical composition of molecular clouds in the universe. In this article we use short (benzene molecules and probe their dynamics using few-cycle VIS/NIR laser pulses. The excited states produced by the XUV pulses lie in an especially complex spectral region where multi-electronic effects play a dominant role. We show that very fast τ ≈ 20 fs nonadiabatic processes dominate the relaxation of these states, in agreement with the timescale expected for most excited cationic states in benzene. In the CH 3 + fragmentation channel of the doubly ionized benzene cation we identify pathways that involve structural rearrangement and proton migration to a specific carbon atom. Further, we observe non-trivial transient behavior in this fragment channel, which can be interpreted either in terms of propagation of the nuclear wavepacket in the initially excited electronic state of the cation or as a two-step electronic relaxation via an intermediate state.

  4. Consistent assignment of the vibrations of symmetric and asymmetric ortho-disubstituted benzenes

    Science.gov (United States)

    Tuttle, William D.; Gardner, Adrian M.; Andrejeva, Anna; Kemp, David J.; Wakefield, Jonathan C. A.; Wright, Timothy G.

    2018-02-01

    The form of molecular vibrations, and changes in these, give valuable insights into geometric and electronic structure upon electronic excitation or ionization, and within families of molecules. Here, we give a description of the phenyl-ring-localized vibrational modes of the ground (S0) electronic states of a wide range of ortho-disubstituted benzene molecules including both symmetrically- and asymmetrically-substituted cases. We conclude that the use of the commonly-used Wilson or Varsányi mode labels, which are based on the vibrational motions of benzene itself, is misleading and ambiguous. In addition, we also find the use of the Mi labels for monosubstituted benzenes [A.M. Gardner, T.G. Wright. J. Chem. Phys. 135 (2011) 114305], or the recently-suggested labels for para-disubstituted benzenes [A. Andrejeva, A.M. Gardner, W.D. Tuttle, T.G. Wright, J. Molec. Spectrosc. 321, 28 (2016)] are not appropriate. Instead, we label the modes consistently based upon the Mulliken (Herzberg) method for the modes of ortho-difluorobenzene (pDFB) under Cs symmetry, since we wish the labelling scheme to cover both symmetrically- and asymmetrically-substituted molecules. By studying the vibrational wavenumbers from the same force field while varying the mass of the substituent, we are able to identify the corresponding modes across a wide range of molecules and hence provide consistent assignments. We assign the vibrations of the following sets of molecules: the symmetric o-dihalobenzenes, o-xylene and catechol (o-dihydroxybenzene); and the asymmetric o-dihalobenzenes, o-halotoluenes, o-halophenols and o-cresol. In the symmetrically-substituted species, we find a pair of in-phase and out-of-phase carbon-substituent stretches, and this motion persists in asymmetrically-substituted molecules for heavier substituents. When at least one of the substituents is light, then we find that these evolve into localized carbon-substituent stretches.

  5. 46 CFR 197.545 - Program to reduce personal exposure.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Program to reduce personal exposure. 197.545 Section 197... HEALTH STANDARDS GENERAL PROVISIONS Benzene § 197.545 Program to reduce personal exposure. (a) When personal exposure for an operation is over the applicable PEL as determined in compliance with § 197.540...

  6. Identifying Sources and Assessing Potential Risk of Exposure to Heavy Metals and Hazardous Materials in Mining Areas: The Case Study of Panasqueira Mine (Central Portugal as an Example

    Directory of Open Access Journals (Sweden)

    Carla Candeias

    2014-09-01

    Full Text Available The Sn-W Panasqueira mine, in activity since the mid-1890s, is one of the most important economic deposits in the world. Arsenopyrite is the main mineral present as well as rejected waste sulphide. The long history is testified by the presence of a huge amount of tailings, which release considerable quantities of heavy metal(loids into the environment. This work assesses soil contamination and evaluates the ecological and human health risks due to exposure to hazardous materials. The metal assemblage identified in soil (Ag-As-Bi-Cd-Cu-W-Zn; potentially toxic elements (PTEs reflects the influence of the tailings, due to several agents including aerial dispersion. PTEs and pH display a positive correlation confirming that heavy metal mobility is directly related to pH and, therefore, affects their availability. The estimated contamination factor classified 92.6% of soil samples as moderately to ultra-highly polluted. The spatial distribution of the potential ecological risk index classified the topsoil as being of a very high ecological risk, consistent with wind direction. Non-carcinogenic hazard of topsoil, for children (1–6 years, showed that for As the non-carcinogenic hazard represents a high health risk. The carcinogenic risks, both for children and adult alike, reveal a very high cancer risk mostly due to As ingestion.

  7. Benzene oxidation under sulfate-reducing conditions in columns simulating in situ conditions.

    Science.gov (United States)

    Vogt, Carsten; Gödeke, Stefan; Treutler, Hanns-Christian; Weiss, Holger; Schirmer, Mario; Richnow, Hans-Hermann

    2007-10-01

    The oxidation of benzene under sulfate-reducing conditions was examined in column and batch experiments under close to in situ conditions. Mass balances and degradation rates for benzene oxidation were determined in four sand and four lava granules filled columns percolated with groundwater from an anoxic benzene-contaminated aquifer. The stoichiometry of oxidized benzene, produced hydrogen carbonate and reduced sulfate correlated well with the theoretical equation for mineralization of benzene with sulfate as electron acceptor. Mean retention times of water in four columns were determined using radon ((222)Rn) as tracer. The retention times were used to calculate average benzene oxidation rates of 8-36 microM benzene day(-1). Benzene-degrading, sulfide-producing microcosms were successfully established from sand material of all sand filled columns, strongly indicating that the columns were colonized by anoxic benzene-degrading microorganisms. In general, these data indicate a high potential for Natural Attenuation of benzene under sulfate-reducing conditions at the field site Zeitz. In spite of this existing potential to degrade benzene with sulfate as electron acceptor, the benzene plume at the field site is much longer than expected if benzene would be degraded at the rates observed in the column experiment, indicating that benzene oxidation under sulfate-reducing conditions is limited in situ.

  8. Soot precursor measurements in benzene and hexane diffusion flames

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Y.; Furuhata, T.; Amagai, K.; Arai, M. [Department of Mechanical System Engineering, Graduate School of Engineering, Gunma University, 1-5-1 Tenjin-cho, Kiryu-shi, Gunma 376-8515 (Japan)

    2008-08-15

    To clarify the mechanism of soot formation in diffusion flames of liquid fuels, measurements of soot and its precursors were carried out. Sooting diffusion flames formed by a small pool combustion equipment system were used for this purpose. Benzene and hexane were used as typical aromatic and paraffin fuels. A laser-induced fluorescence (LIF) method was used to obtain spatial distributions of polycyclic aromatic hydrocarbons (PAHs), which are considered as soot particles. Spatial distributions of soot in test flames were measured by a laser-induced incandescence (LII) method. Soot diameter was estimated from the temporal change of LII intensity. A region of transition from PAHs to soot was defined from the results of LIF and LII. Flame temperatures, PAH species, and soot diameters in this transition region were investigated for both benzene and hexane flames. The results show that though the flame structures of benzene and hexane were different, the temperature in the PAHs-soot transition region of the benzene flame was similar to that of the hexane flame. Furthermore, the relationship between the PAH concentrations measured by gas chromatography in both flames and the PAH distributions obtained from LIF are discussed. It was found that PAHs with smaller molecular mass, such as benzene and toluene, remained in both the PAHs-soot transition and sooting regions, and it is thought that molecules heavier than pyrene are the leading candidates for soot precursor formation. (author)

  9. Identifying important life stages for monitoring and assessing risks from exposures to environmental contaminants: results of a World Health Organization review.

    Science.gov (United States)

    Cohen Hubal, Elaine A; de Wet, Thea; Du Toit, Lilo; Firestone, Michael P; Ruchirawat, Mathuros; van Engelen, Jacqueline; Vickers, Carolyn

    2014-06-01

    In this paper, we summarize exposure-related issues to consider in determining the most appropriate age ranges and life stages for risk assessment. We then propose a harmonized set of age bins for monitoring and assessing risks from exposures to chemicals for global use. The focus is on preconception through adolescence, though the approach should be applicable to additional life stages. A two-tiered set of early life age groups is recommended. The first tier involves the adoption of guidance similar to the childhood age groups recommended by the U.S. Environmental Protection Agency, whereas the second tier consolidates some of those age groups to reduce the burden of developing age-specific exposure factors for different regions. While there is no single "correct" means of choosing a common set of age groups to use internationally in assessing early life exposure and risk, use of a set of defined age groups is recommended to facilitate comparisons of potential exposures and risks around the globe, the collection of data and analyses of aggregate exposure and cumulative risk. Application of these age groups for robust assessment of exposure and risk for specific populations will require region-specific exposure factors as well as local environmental monitoring data. Copyright © 2013 World Health Organization. Published by Elsevier Inc. All rights reserved.

  10. Tandem 1,4-addition reactions with benzene and alkylated benzenes promoted by pentaammineosmium(II).

    Science.gov (United States)

    Ding, Fei; Kopach, Michael E; Sabat, Michal; Harman, W Dean

    2002-11-06

    Electrophiles such as dimethoxymethane and 3-penten-2-one react with the complex [Os(NH(3))(5)(eta(2)-benzene)](2+) in the presence of triflic acid to form metastable benzenium intermediates. These benzenium intermediates further react with carbon nucleophiles including silyl ketene acetals, (silyloxy)alkenes, and phenyllithium in an overall tandem 1,4-addition sequence. The metal fragment controls the relative stereo- and regiochemistry for both electrophilic and nucleophilic addition steps. Upon oxidative demetalation with silver triflate, cis-1,4 cyclohexadienes are formed in yields ranging from 16 to 82%. This methodology can also be used to dearomatize toluene and ortho- and meta-xylene with unexpectedly high regio- and stereocontrol.

  11. Jet Fuel Exposure and Neurological Health in Military Personnel

    Science.gov (United States)

    2011-07-01

    Perspect. 114(2):182–185 (2006). 7. Egeghy, P.P., L. Hauf- Cabalo , R. Gibson, et al.: Benzene and naphthalene in air and breath as indicators of exposure to...cell maintenance workers. Environ Health Perspect 114(2): 182-185. Egeghy P.P., Hauf- Cabalo L., Gibson R., Rappaport S.M.. 2003. Benzene and...compounds in human urine. Chemical Res Toxicol 2009;22:1018-25. Egeghy PP, Hauf- Cabalo L, Gibson R, Rappaport SM. Benzene and naphthalene in air and

  12. [Exposure to VOCs in furniture factories in two populations in northern Colombia].

    Science.gov (United States)

    Vargas-Ramos, Yadiris E; Marrugo-Negrete, José L

    2014-01-01

    Assess the exposure to volatile organic compounds (VOCs)in furniture handicraft factories workers in two populations of Sucre (Sincelejo and Sampués), North of Colombia.Identify possible signs and/or symptoms related to exposure to these contaminants. This was an analytical cross sectional study (2011), using a questionnaire. Study population consisted of 66 individuals, 41 exposed and 25 controls. Personal samples were collected for concentration quantifying of benzene, toluene, ethylbenzene and xylenes (both groups) and contrasting them with health effects possible attributed to these contaminants. The concentrations of benzene, toluene and m/p-xylene were higher in the exposed group (9.5 mg/m(3), 8.1 mg/m(3) and 12.1 mg/m(3))compared with the control group (0.2 mg/m(3), 0.3 mg/m(3) and 0.03 mg/m(3)). Muscular pain 82.9 % (PR=3.8; CI95%:1.2-11.8) and somnolence 65.9 % (PR=4.9; CI95%:1.7-14.7)were associated with a higher exposure.Factor such as mixtures of solvents (thinner) in the work and vehicles' traffic can contribute to these results. Several sources contribute to increases personal exposure of VOCs in furniture handicraft factories workers North of Colombia. Additionally, excessive use of these compounds may be generating adverse effects on the health of workers.

  13. Socioeconomic and personal behavioral factors affecting children's exposure to VOCs in urban areas in Korea.

    Science.gov (United States)

    Byun, Hyaejeong; Ryu, Kyongnam; Jang, Kyungjo; Bae, Hyunjoo; Kim, Dongjin; Shin, Hosung; Chu, Jangmin; Yoon, Chungsik

    2010-02-01

    Volatile organic compounds (VOCs) are known to cause adverse health effects. We investigated the relationships between children's VOC exposure and socioeconomic and human activity factors with passive personal samplers, questionnaires, and time-activity diaries (TAD). Statistical analyses were conducted using SAS 9.1, and the results were organized using SigmaPlot 8.0 software. Chemicals such as benzene, toluene, 2-butanone, ethylbenzene, xylene, chloroform, n-hexane, heptane, and some kinds of decanes, which are known to adversely affect public health, were identified in measured samples. These were mainly emitted from outdoor sources (e.g., vehicular traffic) or indoor sources (e.g., household activities such as cooking and cleaning) or both. We concluded that region was the most important socioeconomic factor affecting children's VOC exposure, and the significant compounds were n-hexane (p = 0.006), 1,1,1-trichloroethane (p = 0.001), benzene (p = 0.003), toluene (p = 0.002), ethylbenzene (p = 0.020), m-, p-xylene (p = 0.014), dodecane (p = 0.003), and hexadecane (p = 0.001). Parental education, year of home construction and type of housing were also slightly correlated with personal VOC exposure. Only the concentration of o-xylene (p = 0.027) was significantly affected by the parental education, and the concentrations of benzene (p = 0.030) and 2-butanone (p = 0.049) by the type of housing. Also, tridecane (p = 0.049) and n-hexane (p = 0.033) were significantly associated with the year of home construction. When household activities such as cooking were performed indoors, children's VOC concentrations tended to be higher, especially for n-hexane, chloroform, heptane, toluene (p factors simultaneously, socioeconomic factors such as region had a greater effect on children's VOC exposures than indoor activities. From this study, we can suggest that socioeconomic factors as well as environmental factors should be considered when formulating environmental policy to

  14. Measurement of personal exposure to volatile organic compounds and particle associated PAH in three UK regions.

    Science.gov (United States)

    Saborit, Juana Mari Delgado; Aquilina, Noel J; Meddings, Claire; Baker, Stephen; Vardoulakis, Sotiris; Harrison, Roy M

    2009-06-15

    Personal exposures to 15 volatile organic compounds (VOC) and 16 polycyclic aromatic hydrocarbons (PAH) of 100 adult nonsmokers living in three UK areas, namely London, West Midlands, and rural South Wales, were measured using an actively pumped sampler carried around by the volunteers for 5/1 (VOC/PAH) consecutive 24-h periods, following their normal lifestyle. Results from personal exposure measurements categorized by geographical location, type of dwelling, and exposure to environmental tobacco smoke (ETS) are presented. The average personal exposure concentration to benzene, 1,3-butadiene, and benzo(a)pyrene representing the main carcinogenic components of the VOC and PAH mixture were 2.2 +/- 2.5 microg/m3, 0.4 +/- 0.7 microg/m3, and 0.3 +/- 0.7 ng/m3 respectively. The association of a number of generic factors with personal exposure concentrations was investigated, including first-line property, traffic, the presence of an integral garage, and ETS. Only living in houses with integral garages and being exposed to ETS were identified as unequivocal contributors to VOC personal exposure, while only ETS had a clear effect upon PAH personal exposures. The measurements of personal exposures were compared with health-based European and UK air quality guidelines, with some exceedences occurring. Activities contributing to high personal exposures included the use of a fireplace in the home, ETS exposure, DIY (i.e., construction and craftwork activities), and photocopying, among others.

  15. 29 CFR 1910.1028 - Benzene.

    Science.gov (United States)

    2010-07-01

    ... to keep exposures below 10 ppm unless it is proven to be not feasible. (b) Definitions. Action level... laboratory for the particular geographic area and/or these indices show a persistent downward trend from the... scatter and spread fire. Fine water spray can be used to keep fire-exposed containers cool. 6. Unusual...

  16. Unleaded gasoline with reduction in benzene and aromatics

    International Nuclear Information System (INIS)

    Ahmed, I.

    2003-01-01

    The trend today is towards making gasoline more environment and human friendly or in other words making gasoline a really clean fuel. This paper covers the ill effects of benzene and aromatics and the driving force behind their reduction in gasoline worldwide. It addresses health concerns specifically, and the theme is unleaded gasoline without simultaneously addressing reduction in benzene and aromatics is more harmful. The paper cites worldwide case studies, and also the World Bank (WB), Government of Pakistan (GoP), and United Nations (UN) efforts in this area in Pakistan. (author)

  17. Critical issues in benzene toxicity and metabolism: the effect of interactions with other organic chemicals on risk assessment.

    OpenAIRE

    Medinsky, M A; Schlosser, P M; Bond, J A

    1994-01-01

    Benzene, an important industrial solvent, is also present in unleaded gasoline and cigarette smoke. The hematotoxic effects of benzene are well documented and include aplastic anemia and pancytopenia. Some individuals exposed repeatedly to cytotoxic concentrations of benzene develop acute myeloblastic anemia. It has been hypothesized that metabolism of benzene is required for its toxicity, although administration of no single benzene metabolite duplicates the toxicity of benzene. Several inve...

  18. Draft Benzene Case Study Review - Second Prospective Report Study Science Advisory Board Review, March 2008

    Science.gov (United States)

    EPA developed a methodology for estimating the health benefits of benzene reductions and has applied it in a metropolitan-scale case study of the benefits of CAA controls on benzene emissions to accompany the main 812 analysis.

  19. Benzene Case Study Final Report - Second Prospective Report Study Science Advisory Board Review, July 2009

    Science.gov (United States)

    EPA developed a methodology for estimating the health benefits of benzene reductions and has applied it in a metropolitan-scale case study of the benefits of CAA controls on benzene emissions to accompany the main 812 analysis.

  20. Benzene solubility in ionic liquids: working toward an understanding of liquid clathrate formation.

    Science.gov (United States)

    Pereira, Jorge F B; Flores, Luis A; Wang, Hui; Rogers, Robin D

    2014-11-17

    The solubility of benzene in 15 imidazolium, pyrrolidinium, pyridinium, and piperidinium ionic liquids has been determined; the resulting, benzene-saturated ionic liquid solutions, also known as liquid clathrates, were examined with (1) H and (19) F nuclear magnetic resonance spectroscopy to try and understand the molecular interactions that control liquid clathrate formation. The results suggest that benzene interacts primarily with the cation of the ionic liquid, and that liquid clathrate formation (and benzene solubility) is controlled by the strength of the cation-anion interactions, that is, the stronger the cation-anion interaction, the lower the benzene solubility. Other factors that were determined to be important in the final amount of benzene in any given liquid clathrate phase included attractive interactions between the anion and benzene (when significant), and larger steric or free volume demands of the ions, both of which lead to greater benzene solubility. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Toxicokinetics of halogenated benzenes in fish: Lethal body burden as a toxicological end point

    Energy Technology Data Exchange (ETDEWEB)

    Sijm, D.T.H.M.; Schipper, M.; Opperhuizen, A. (University of Utrecht, (Netherlands). Research Inst. of Toxicology)

    1993-06-01

    The lethal body burden (LBB), the whole-body concentration in millimoles per kilogram at time of death or immobilization, and the LC50 of dihalogenated (F,Cl,Br) benzenes were measured. Except for 1,4-difluorobenzene in guppy, LBBs varied between 2 and 8 mmol kg[sub [minus]8]. The LBBs of the chemicals in guppies were not significantly different from those in fat head minnows. LC50 values varied between 0.54 and 41 [mu]mol L[sub [minus]1] and were inversely related to the octanol/water partition coefficient, K[sub ow]. To estimate the risk of a compound to fish, the LBB requires the exposure concentration in combination with a first-order one-compartment bioaccumulation model. Therefore, the time of death or the time of immobility, and bioconcentration parameters such as the uptake rate constant (k[sub 1]) and the elimination rate constant (k[sub 2]), were determined. For both species, k[sub 1] values of the chlorinated benzenes were smaller than those of the brominated compounds and k[sub 2] values decreased with increasing hydrophobicity. The lipid-normalized bioaccumulation factors (k[sub l]'s) were linearly related to K[sub ow].

  2. High level theoretical study of binding and of the potential energy surface in benzene-hydride system

    Energy Technology Data Exchange (ETDEWEB)

    Coletti, Cecilia, E-mail: ccoletti@unich.it [Dipartimento di Scienze del Farmaco, Universita ' G. d' Annunzio' Chieti-Pescara, Via dei Vestini 31, 66100 Chieti (Italy); Re, Nazzareno [Dipartimento di Scienze del Farmaco, Universita ' G. d' Annunzio' Chieti-Pescara, Via dei Vestini 31, 66100 Chieti (Italy)

    2012-04-04

    Graphical abstract: In-plane minimum geometries for benzene-H{sup -} non-covalent adducts: linear adduct (left) with the hydride ion hydrogen bonded to one aromatic hydrogen; bifurcated adduct (right), with the hydride ion hydrogen bonded to two adjacent aromatic hydrogens. Highlights: Black-Right-Pointing-Pointer Theoretical study on covalent and non-covalent binding in benzene-hydride. Black-Right-Pointing-Pointer Two non-covalent stable adducts were characterized in the in-plane geometry. Black-Right-Pointing-Pointer Significant sections of the potential energy surface were determined. Black-Right-Pointing-Pointer Formation of a very stable C{sub 6}H{sub 7}{sup -} anion upon covalent binding to carbon. - Abstract: High level ab initio calculations were performed on the interaction of the hydride anion with benzene, a system of potential interest for modelling the interactions occurring in hydrogen rich planetary atmospheres. We investigated both non-covalent and covalent binding, exploring the complete basis set limit using highly correlated MP2 and CCSD(T) levels of theory. Two non-covalent minima on the potential energy surface have been characterized, and found to correspond to moderately strong hydrogen bonding interactions. To gain further insight on the nature of binding, the total interaction energy was decomposed into its physically meaningful components and selected sections of the potential energy surface were calculated. Moreover, we found that H{sup -} can easily covalently bind to one of the carbon atoms of benzene to form a stable C{sub 6}H{sub 7}{sup -} anion, a global minimum on the potential energy surface, characterized by a puckered geometry, with a carbon atom bending out of the benzene plane. A slightly less stable planar C{sub 6}H{sub 7}{sup -} structure was also identified, corresponding to the transition state for the flipping motion of the puckered species.

  3. Systemic Approach for Health Risk Assessment of Ambient Air Concentrations of Benzene in Petrochemical Environments: Integration of Fuzzy Logic, Artificial Neural Network, and IRIS Toxicity Method.

    Science.gov (United States)

    Novin, Vahid; Givehchi, Saeed; Hoveidi, Hassan

    2016-09-01

    Reliable methods are crucial to cope with uncertainties in the risk analysis process. The aim of this study is to develop an integrated approach to assessing risks of benzene in the petrochemical plant that produces benzene. We offer an integrated system to contribute imprecise variables into the health risk calculation. The project was conducted in Asaluyeh, southern Iran during the years from 2013 to 2014. Integrated method includes fuzzy logic and artificial neural networks. Each technique had specific computational properties. Fuzzy logic was used for estimation of absorption rate. Artificial neural networks can decrease the noise of the data so applied for prediction of benzene concentration. First, the actual exposure was calculated then it combined with Integrated Risk Information System (IRIS) toxicity factors to assess real health risks. High correlation between the measured and predicted benzene concentration was achieved (R 2 = 0.941). As for variable distribution, the best estimation of risk in a population implied 33% of workers exposed less than 1×10 -5 and 67% inserted between 1.0×10 -5 to 9.8×10 -5 risk levels. The average estimated risk of exposure to benzene for entire work zones is equal to 2.4×10 -5 , ranging from 1.5×10 -6 to 6.9×10 -5 . The integrated model is highly flexible as well as the rules possibly will be changed according to the necessities of the user in a different circumstance. The measured exposures can be duplicated well through proposed model and realistic risk assessment data will be produced.

  4. Interim report: Study of benzene release from Savannah River in-tank precipitation process slurry simulant

    International Nuclear Information System (INIS)

    Rappe, K.G.; Gauglitz, P.A.

    1997-09-01

    At the Savannah River Site, the in-tank precipitation (ITP) process uses sodium tetraphenylborate (NaTPB) to precipitate radioactive cesium from alkaline wastes. During this process, potassium is also precipitated to form a 4-wt% KTPB/CsTPB slurry. Residual NaTPB decomposes to form benzene, which is retained by the waste slurry. The retained benzene is also readily released from the waste during subsequent waste processing. While the release of benzene certainly poses both flammability and toxicological safety concerns, the magnitude of the hazard depends on the rate of release. Currently, the mechanisms controlling the benzene release rates are not well understood, and predictive models for estimating benzene release rates are not available. The overall purpose of this study is to obtain quantitative measurements of benzene release rates from a series of ITP slurry stimulants. This information will become a basis for developing a quantitative mechanistic model of benzene release rates. The transient benzene release rate was measured from the surface of various ITP slurry (solution) samples mixed with benzene. The benzene release rate was determined by continuously purging the headspace of a sealed sample vessel with an inert gas (nitrogen) and analyzing that purged headspace vapor for benzene every 3 minutes. The following 75-mL samples were measured for release rates: KTPB slurry with 15,000 ppm freshly added benzene that was gently mixed with the slurry, KTPB slurry homogenized (energetically mixed) with 15,000 ppm and 5,000 ppm benzene, clear and filtered KTPB salt solution saturated with benzene (with and without a pure benzene layer on top of the solution), and a slurry sample from a large demonstration experiment (DEMO slurry) containing-benzene generated in situ

  5. Utilization of alternative fuels and materials in cement kiln towards emissions of benzene, toluene, ethyl-benzene and xylenes (BTEX)

    OpenAIRE

    Muliane Ulfi; Lestari Puji

    2018-01-01

    Co-processing in cement industry has benefits for energy conservation and waste recycling. Nevertheless, emissions of benzene, toluene, ethyl-benzene, and xylenes (BTEX) tend to increase compared to a non co-processing kiln. A study was conducted in kiln feeding solid AFR (similar to municipal solid waste, MSW) having production capacity 4600-ton clinker/day (max. 5000 ton/day) and kiln feeding biomass having production capacity 7800-ton clinker/day (max. 8000 ton/day). The concentration of V...

  6. 40 CFR 80.1275 - How are early benzene credits generated?

    Science.gov (United States)

    2010-07-01

    ...), per § 80.1280(a). Bavg,y = Average benzene concentration of gasoline produced at the refinery during averaging period y (volume percent benzene), per § 80.1238. Ve,y = Total volume of gasoline produced at the... PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Benzene Averaging, Banking and Trading...

  7. 40 CFR 80.1225 - Who must register with EPA under the gasoline benzene program?

    Science.gov (United States)

    2010-07-01

    ... gasoline benzene program? 80.1225 Section 80.1225 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Benzene General Information § 80.1225 Who must register with EPA under the gasoline benzene program? (a) Refiners and...

  8. 78 FR 25476 - Agency Information Collection Activities; Submission for OMB Review; Comment Request; Benzene...

    Science.gov (United States)

    2013-05-01

    ...; Benzene Standard ACTION: Notice. SUMMARY: On April 30, 2013, the Department of Labor (DOL) will submit the..., ``Benzene Standard,'' to the Office of Management and Budget (OMB) for review and approval for continued [email protected] . Authority: 44 U.S.C. 3507(a)(1)(D). SUPPLEMENTARY INFORMATION: The Benzene Standard requires...

  9. 40 CFR 80.1361 - What penalties apply under the gasoline benzene program?

    Science.gov (United States)

    2010-07-01

    ... gasoline benzene program? 80.1361 Section 80.1361 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Benzene Violations and Penalties § 80.1361 What penalties apply under the gasoline benzene program? (a) Any person liable for a...

  10. 40 CFR 80.1358 - What acts are prohibited under the gasoline benzene program?

    Science.gov (United States)

    2010-07-01

    ... gasoline benzene program? 80.1358 Section 80.1358 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Benzene Violations and Penalties § 80.1358 What acts are prohibited under the gasoline benzene program? No person shall— (a)(1...

  11. 40 CFR 80.1354 - What are the reporting requirements for the gasoline benzene program?

    Science.gov (United States)

    2010-07-01

    ... for the gasoline benzene program? 80.1354 Section 80.1354 Protection of Environment ENVIRONMENTAL... Benzene Recordkeeping and Reporting Requirements § 80.1354 What are the reporting requirements for the gasoline benzene program? (a) Beginning with earliest applicable date specified in § 80.1347(a)(2), any...

  12. 46 CFR Appendix B to Subpart C to... - Substance Technical Guidelines, Benzene

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Substance Technical Guidelines, Benzene B Appendix B to... OCCUPATIONAL SAFETY AND HEALTH STANDARDS GENERAL PROVISIONS Benzene Pt. 197, Subpt. C, App. B Appendix B to Subpart C to Part 197—Substance Technical Guidelines, Benzene I. Physical and Chemical Data (a) Substance...

  13. How to identify partial exposures to ionizing radiation? Proposal for a cytogenetic method; Como identificar exposicoes parciais as radiacoes ionizantes? Proposta de um metodo citogenetico

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, T.S.; Silva, E.B.; Pinto, M.M.P.L.; Amaral, A., E-mail: thiagosalazar@hotmail.com [Universidade Federal de Pernambuco (LAMBDA/UFPE), Recife, PE (Brazil). Departamento de Energia Nuclear. Lab. de Modelagem e Biodosimetria Aplicada; Lloyd, David [Health Protection Agency, Oxford (United Kingdom). Radiation Protection Division

    2013-08-15

    In cases of radiological incidents or in occupational exposures to ionizing radiation, the majority of exposures are not related to the total body, but only partial. In this context, if the cytogenetic dosimetry is performed, there will be an underestimation of the absorbed dose due to the dilution of irradiated cells with non-irradiated cells. Considering the norms of NR 32 - Safety and Health in the Work of Health Service - which recommends cytogenetic dosimetry in the investigation of accidental exposures to ionizing radiations, it is necessary to develop of a tool to provide a better identification of partial exposures. With this aim, a partial body exposure was simulated by mixing, in vitro, 70% of blood irradiated with 4 Gy of X-rays with 30% of unirradiated blood from the same healthy donor. Aliquots of this mixture were cultured for 48 and 72 hours. Prolonging the time of cell culture from 48 to 72 hours produced no significant change in the yield of dicentrics. However, when only M1 (first division cells) were analyzed, the frequency of dicentrics per cell was increased. Prolonging the time of cell culture allowed cells in mitotic delay by irradiation to reach metaphase, and thus provides enough time for the damage to be visualized. The results of this research present the proposed method as an important tool in the investigation of exposed individuals, allowing associating the cytogenetic analysis with the real percentage of irradiated cells, contributing significantly for the decision making in terms of occupational health. (author)

  14. Hydroxylation of Benzene via CH Activation Using Bimetallic ...

    Science.gov (United States)

    A photoactive bimetallic CuAg@g-C3N4 catalyst system has been designed and synthesized by impregnating copper and silver nanoparticles over the graphitic carbon nitride surface. Its application has been demonstrated in the hydroxylation of benzene under visible light. Prepared for submission to American Chemical Society (ACS) journal, ACS Sustainable Chemistry & Engineering.

  15. Fluorescent naphthalene-based benzene tripod for selective ...

    Indian Academy of Sciences (India)

    Aluminium complex of a naphthalene-based benzene tripod ligand system has been reported for the selective recognition of fluoride in aqueous medium in physiological condition. The ligand can selectively recognize Al3+ through enhancement in the fluorescence intensity and this in situ formed aluminium complex ...

  16. Degradation of benzene and other aromatic hydrocarbons by anaerobic bacteria

    NARCIS (Netherlands)

    Weelink, S.A.B.

    2008-01-01

    Accidental spills, industrial discharges and gasoline leakage from underground storage tanks have resulted in serious pollution of the environment with monoaromatic hydrocarbons, such as benzene, toluene, ethylbenzene and xylene (so-called BTEX). High concentrations of BTEX have been detected in

  17. Isopropylation of benzene with 2-propanol over substituted large ...

    Indian Academy of Sciences (India)

    The catalytic performance of these materials was tested for isopropylation of benzene with 2-propanol at 250, 300, 350 and 400°C. The products were cumene, -DIPB (-diisopropylbenzene) and -DIPB (-diisopropylbenzene). MnAPO-5 was found to be more active than the other catalysts. Maximum conversion (20%) ...

  18. Electronic states of 1,4-bis(phenylethynyl)benzene

    DEFF Research Database (Denmark)

    Nguyen, Duy Duc; Jones, Nykola; Hoffmann, Søren Vrønning

    2012-01-01

    The electronic transitions of 1,4-bis(phenylethynyl)benzene (BPEB) were investigated by UV synchrotron radiation linear dichroism (SRLD) spectroscopy in the range 25,000 – 58,000 cm–1 (400 – 170 nm) on molecular samples aligned in stretched polyethylene. The investigation was supported by variable...

  19. Resonance energy in benzene derivatives with a variable functional group

    Czech Academy of Sciences Publication Activity Database

    Exner, Otto; Böhm, S.

    2001-01-01

    Roč. 66, č. 11 (2001), s. 1623-1637 ISSN 0010-0765 R&D Projects: GA ČR GA203/99/1454 Institutional research plan: CEZ:AV0Z4055905 Keywords : arenes * benzene Subject RIV: CC - Organic Chemistry Impact factor: 0.778, year: 2001

  20. 46 CFR 197.565 - Notifying personnel of benzene hazards.

    Science.gov (United States)

    2010-10-01

    ...) Material safety data sheet. A material safety data sheet (MSDS) addressing benzene must be made available... 197.565 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE OCCUPATIONAL SAFETY... A through E of this subpart and on where copies of this material are available; and (viii) The...

  1. Assessment of uncertainty of benzene measurements by Radiello diffusive sampler

    Science.gov (United States)

    Plaisance, Hervé; Leonardis, Thierry; Gerboles, Michel

    The uncertainty of benzene measurements obtained by the analysis of thermally desorbable Radiello diffusive samplers was evaluated according to the recent standard EN 14662-4 [EN 14662-4, 2005. Ambient air quality. Standard method for measurement of benzene concentrations. Part 4: diffusive sampling followed by thermal desorption and gas chromatography]. Considering the results of laboratory experiments, all the sources of uncertainty regarding the diffusive sampler method characteristics were accessed for the sampling times of 7 and 14 days. The major part of the uncertainty budget (>79%) was explained by the variation of the sampling rate due to the environmental factors (temperature and concentration level). For weekly sampling, the diffusive sampler method satisfies the data quality objectives of the European Directive to supply the indicative measurements as well as the reference measurement, since the expanded uncertainty is found workplaces. For 2-week sampling, the expanded uncertainty of measurements exceeds 30%. However, this diffusive sampler can still be used to carry out an objective evaluation of benzene (minimum quality objective for the accuracy of 100%). Therefore, the performance of this diffusive sampler method appears to be suitable for the benzene monitoring in ambiant air.

  2. Instrument for benzene and toluene emission measurements of glycol regenerators

    International Nuclear Information System (INIS)

    Hanyecz, Veronika; Szabó, Gábor; Mohácsi, Árpád; Puskás, Sándor; Vágó, Árpád

    2013-01-01

    We introduce an in-field and in-explosive atmosphere useable instrument, which can measure the benzene and toluene concentration in two gas and two glycol samples produced by natural gas dehydration units. It is a two-phase, on-line gas chromatograph with a photoacoustic spectroscopy based detector. The time resolution is 10 min per cycle and the minimum detectable concentrations are 2 mg m −3 for benzene, 3 mg m −3 for toluene in natural gas, and 5 g m −3 for benzene and 6 g m −3 for toluene in glycol. Test measurements were carried out at a dehydration plant belonging to MOL Hungarian Oil and Gas Company. Benzene and toluene emissions of gas dehydration unit are calculated from the measured values based on mass balance of a glycol regenerator. The relationship between the outdoor temperature and the measured concentration was observed which is caused by temperature-dependent operation of the whole dehydration unit. Emission decreases with increase of outdoor temperature. (paper)

  3. Source attribution and quantification of benzene event emissions in a Houston ship channel community based on real-time mobile monitoring of ambient air.

    Science.gov (United States)

    Olaguer, Eduardo P; Erickson, Matthew H; Wijesinghe, Asanga; Neish, Bradley S

    2016-02-01

    A mobile laboratory equipped with a proton transfer reaction mass spectrometer (PTR-MS) operated in Galena Park, Texas, near the Houston Ship Channel during the Benzene and other Toxics Exposure Study (BEE-TEX). The mobile laboratory measured transient peaks of benzene of up to 37 ppbv in the afternoon and evening of February 19, 2015. Plume reconstruction and source attribution were performed using the four-dimensional (4D) variational data assimilation technique and a three-dimensional (3D) micro-scale forward and adjoint air quality model based on mobile PTR-MS data and nearby stationary wind measurements at the Galena Park Continuous Air Monitoring Station (CAMS). The results of inverse modeling indicate that significant pipeline emissions of benzene may at least partly explain the ambient concentration peaks observed in Galena Park during BEE-TEX. Total pipeline emissions of benzene inferred within the 16-km(2) model domain exceeded point source emissions by roughly a factor of 2 during the observational episode. Besides pipeline leaks, the model also inferred significant benzene emissions from marine, railcar, and tank truck loading/unloading facilities, consistent with the presence of a tanker and barges in the Kinder Morgan port terminal during the afternoon and evening of February 19. Total domain emissions of benzene exceeded corresponding 2011 National Emissions Inventory (NEI) estimates by a factor of 2-6. Port operations involving petrochemicals may significantly increase emissions of air toxics from the transfer and storage of materials. Pipeline leaks, in particular, can lead to sporadic emissions greater than in emission inventories, resulting in higher ambient concentrations than are sampled by the existing monitoring network. The use of updated methods for ambient monitoring and source attribution in real time should be encouraged as an alternative to expanding the conventional monitoring network.

  4. Reactions between aromatic hydrocarbons and heterocycles: covalent and proton-bound dimer cations of benzene/pyridine.

    Science.gov (United States)

    El-Shall, M Samy; Ibrahim, Yehia M; Alsharaeh, Edreese H; Meot-Ner Mautner, Michael; Watson, Simon P

    2009-07-29

    Despite the fact that benzene (Bz) and pyridine (Py) are probably the most common and extensively studied organic molecules, the observation of a covalent adduct in the ionized benzene/pyridine system has never been reported. This Article reports the first experimental and theoretical evidence of a covalent (Bz x Py)(*+) adduct that results from the reaction of Bz(*+) with pyridine or Py(*+) with benzene. These reactions are studied using mass-selected ion mobility, chemical reactivity, collisional dissociation, and ab initio calculations. The (Bz x Py)(*+) adduct does not exchange ligands with Bz to form Bz(2)(*+) or with Py to form (Py)(2)H(+) despite the strong bonds in these homodimers. The thermochemistry then suggests that the (Bz x Py)(*+) heterodimer is bonded covalently with a bonding energy of >33 kcal/mol. Correspondingly, ab initio calculations identify covalently bonded propeller-shaped isomers of (Bz x Py)(*+) with bonding energies of 31-38 kcal/mol, containing a C-N bond. The mobility of the (Bz x Py)(*+) adduct in helium is consistent with these covalent dimers. As to noncovalent adducts, the computations identify novel distonic hydrogen-bonded complexes (C(5)H(5)NH(+) x C(6)H(5)(*)) where the charge resides on one component (PyH(+)), while the radical site resides on the other component (C(6)H(5)(*)). Collisional dissociation suggests that the covalent and distonic dimers may interconvert at high energies. The most stable distonic (C(5)H(5)NH(+) x C(6)H(5)(*)) complex contains a hydrogen bond to the phenyl radical carbon site with a calculated dissociation energy of 16.6 kcal/mol. This bond is somewhat stronger than the NH(+) x pi hydrogen bonds of PyH(+) to the pi system of the phenyl radical and of the benzene molecule. For this NH(+) x pi bond in the PyH(+) x Bz dimer, the measured binding energy is 13.4 kcal/mol, and ab initio calculations identify two T-shaped isomers with the NH(+) pointing to the center of the benzene ring or to the

  5. Structural study of a novel acetylide-thiourea derivative and its evaluation as a detector of benzene

    Science.gov (United States)

    Khairul, Wan M.; Daud, Adibah Izzati; Mohd Hanifaah, Noor Azura; Arshad, Suhana; Razak, Ibrahim Abdul; Zuki, Hafiza Mohamed; Erben, Mauricio F.

    2017-07-01

    The new derivative 1-hexanoyl-3-(4-p-tolylethynyl-phenyl)-thiourea (APHX) was synthesised by the addition reaction between 4[4-aminophenyl] ethynyltoluene and hexanoyl isothiocyanate in acetone. The acetylide group was incorporated by using Sonogashira cross-coupling reaction allowing for the preparation of acetylide-thiourea compound. APHX was then elucidated via single crystal X-ray crystallography analysis, spectroscopic and elemental analysis by Fourier Transform Infrared (FT-IR) spectroscopy, 1H and 13C Nuclear Magnetic Resonance (NMR), UV-visible analysis, CHNS-elemental analysis. APHX was also evaluated theoretically via density functional theory (DFT) approach. APHX was fabricated onto glass substrate via drop-cast technique prior to act as optical thin-film and its performance as volatile organic compounds (VOCs) sensor was investigated through the difference in UV-vis profile before and after exposure towards benzene. Preliminary findings revealed that APHX showed interaction towards benzene with about 48% sensitivity. According to thermogravimetric studies, APHX showed good thermal stability, without decomposition up to ca. 190 °C. Whilst, crystal structure of APHX consists in a nearly planar acylthiourea moiety with the Cdbnd O and Cdbnd S bonds utilizing trans position, favoring by an intramolecular Nsbnd H⋯Odbnd C hydrogen bonds. The alkyl chain is oriented 90° with respect to acylthiourea group. The phenyls group in the 1-methyl-4-(phenylethynyl)benzene moieties are mutually planar and slightly twisted with respect to the acylthiourea plane. Centrosymmetric dimers generated by intermolecular Nsbnd H⋯Sdbnd C and Csbnd H⋯Sdbnd C hydrogen bonds forming R22 (8) and R21(6) motifs are present in the crystals. The interaction between APHX with benzene has been modelled and calculated using density functional theory (DFT) via Gaussian 09 software package and the preferred sites of binding are located at the acylthiourea group.

  6. Inhibitory effect of benzene metabolites on nuclear DNA synthesis in bone marrow cells

    International Nuclear Information System (INIS)

    Lee, E.W.; Johnson, J.T.; Garner, C.D.

    1989-01-01

    Effects of endogenously produced and exogenously added benzene metabolites on the nuclear DNA synthetic activity were investigated using a culture system of mouse bone marrow cells. Effects of the metabolites were evaluated by a 30-min incorporation of [ 3 H]thymidine into DNA following a 30-min interaction with the cells in McCoy's 5a medium with 10% fetal calf serum. Phenol and muconic acid did not inhibit nuclear DNA synthesis. However, catechol, 1,2,4-benzenetriol, hydroquinone, and p-benzoquinone were able to inhibit 52, 64, 79, and 98% of the nuclear DNA synthetic activity, respectively, at 24 μM. In a cell-free DNA synthetic system, catechol and hydroquinone did not inhibit the incorporation of [ 3 H]thymidine triphosphate into DNA up to 24 μM but 1,2,4-benzenetriol and p-benzoquinone did. The effect of the latter two benzene metabolites was completely blocked in the presence of 1,4-dithiothreitol (1 mM) in the cell-free assay system. Furthermore, when DNA polymerase α, which requires a sulfhydryl (SH) group as an active site, was replaced by DNA polymerase 1, which does not require an SH group for its catalytic activity, p-benzoquinone and 1,2,4-benzenetriol were unable to inhibit DNA synthesis. Thus, the data imply the p-benzoquinone and 1,2,4-benzenetriol inhibited DNA polymerase α, consequently resulting in inhibition of DNA synthesis in both cellular and cell-free DNA synthetic systems. The present study identifies catechol, hydroquinone, p-benzoquinone, and 1,2,4-benzenetriol as toxic benzene metabolites in bone marrow cells and also suggests that their inhibitory action on DNA synthesis is mediated by mechanism(s) other than that involving DNA damage as a primary cause

  7. 46 CFR 197.540 - Determination of personal exposure.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Determination of personal exposure. 197.540 Section 197.540 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE OCCUPATIONAL SAFETY AND HEALTH STANDARDS GENERAL PROVISIONS Benzene § 197.540 Determination of personal exposure. (a) General. (1...

  8. 46 CFR 197.515 - Permissible exposure limits (PELs).

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Permissible exposure limits (PELs). 197.515 Section 197.515 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE OCCUPATIONAL SAFETY AND HEALTH STANDARDS GENERAL PROVISIONS Benzene § 197.515 Permissible exposure limits (PELs). The permissible...

  9. Appraisal of levels and patterns of occupational exposure to 1,3-butadiene.

    Science.gov (United States)

    Scarselli, Alberto; Corfiati, Marisa; Di Marzi, Davide; Iavicoli, Sergio

    2017-09-01

    Objectives 1,3-butadiene is classified as carcinogenic to human by inhalation and the association with leukemia has been observed in several epidemiological studies. The aim of this study was to evaluate data about occupational exposure levels to 1,3-butadiene in the Italian working force. Methods Airborne concentrations of 1,3-butadiene were extracted from the Italian database on occupational exposure to carcinogens in the period 1996-2015. Descriptive statistics were calculated for exposure-related variables. An analysis through linear mixed model was performed to determine factors influencing the exposure level. The probability of exceeding the exposure limit was predicted using a mixed-effects logistic model. Concurrent exposures with other occupational carcinogens were investigated using the two-step cluster analysis. Results The total number of exposure measurements selected was 23 885, with an overall arithmetic mean of 0.12 mg/m3. The economic sector with the highest number of measurements was manufacturing of chemicals (18 744). The most predictive variables of the exposure level resulted to be the occupational group and its interaction with the measurement year. The highest likelihood of exceeding the exposure limit was found in the manufacture of coke and refined petroleum products. Concurrent exposures were frequently detected, mainly with benzene, acrylonitrile and ethylene dichloride, and three main clusters were identified. Conclusions Exposure to 1,3-butadiene occurs in a wide variety of activity sectors and occupational groups. The use of several statistical analysis methods applied to occupational exposure databases can help to identify exposure situations at high risk for workers' health and better target preventive interventions and research projects.

  10. Supplementary measurements for air monitoring under NOVANA - Benzene and PAH; Supplerende maalinger til luftovervaagning under NOVANA - benzen og PAH

    Energy Technology Data Exchange (ETDEWEB)

    Ellermann, T.; Klenoe Noejgaard, J.; Bossi, R.

    2011-10-15

    The report presents results from a project carried out for the Danish Environmental Protection Agency. The aim of the project was to carry out several measuring campaigns in order to be able to better assess the monitoring needs for PAH and benzene in relation to EU's air quality directives. The results show that the mean concentrations of benzene are almost at the same level in Denmark's four largest cities, and that the concentrations are both below the threshold value (5mug/m3) as well as below the lower assessment threshold (2mug/m3). The report presents a method for objectively estimation the benzene concentration based on measurements of CO. The method can be applied to fulfil the monitoring need for benzene in those zones where no measurements of benzene are made. Measurements of PAH, especially benzo(a)pyrene, have been made during 12 months in the period 2010-2011 in an area with many wood burning furnaces are used (the town Jyllinge). The concentrations of benzo(a)pyrene in Jyllinge is almost three times higher than in the street H.C. Andersens Boulevard in Copenhagen. The concentrations of benzo(a)pyrene in Jylllinge are 0,6 ng/m3, which corresponds to the upper assessment threshold (0,6 ng/m3) and is 40% below the measuring value (1 ng/m3). On this basis, there is a need for re-evaluating the monitoring of PAH in the sub-programme for air under NOVANA. Measurements of PM{sub 10} showed that the levels in the towns Jyllinge, Lille Valby/Risoe and at the H.C. Oersted Institute in Copenhagen are all at about 20-22 mug/m3. (LN)

  11. Modeling annual benzene, toluene, NO2, and soot concentrations on the basis of road traffic characteristics

    International Nuclear Information System (INIS)

    Carr, David; Ehrenstein, Ondine von; Weiland, Stephan; Wagner, Claudia; Wellie, Oliver; Nicolai, Thomas; Mutius, Erika von

    2002-01-01

    The investigation of potential adverse health effects of urban traffic-related air pollution is hampered by difficulties encountered with exposure assessment. Usually public measuring sites are few and thereby do not adequately describe spatial variation of pollutant levels over an urban area. In turn, individual monitoring of pollution exposure among study subjects is laborious and expensive. We therefore investigated whether traffic characteristics can be used to adequately predict benzene, NO 2 , and soot concentrations at individual addresses of study subjects in the city area of Munich, Germany. For all road segments with expected traffic volumes of at least 4000 vehicles a day (n=1840), all vehicles were counted manually or a single weekday in 1995. The proportion of vehicles in 'stop-go' mode, n estimate of traffic jam, was determined. Furthermore, annual concentrations of benzene, NO 2 , and soot from 18 high-concentration sites means: 8.7, 65.8, and 12.9 μg/m 3 , respectively) and from 16 school sites with moderate concentrations (means: 2.6, 32.2, and 5.7 μg/m 3 , respectively) were measured from 1996 to 1998. Statistical analysis of the data was performed using components of two different statistical models recently used to predict air pollution levels in comparable settings. Two traffic characteristics, traffic volume and traffic jam percentage, adequately described air pollutant concentrations (R 2 : 0.76-0.80, P=0.0001). This study shows that air pollutant concentrations can be accurately predicted by two traffic characteristics and that these models compare favorably with other more complex models in the literature

  12. Study of benzene release from Savannah River in-tank precipitation process slurry simulant

    International Nuclear Information System (INIS)

    Rappe, K.G.; Gauglitz, P.A.

    1998-08-01

    At the Savannah River Site, the in-tank precipitation (ITP) process uses sodium tetraphenylborate (NaTPB) to precipitate radioactive cesium from alkaline wastes. During this process, potassium is also precipitated to form 4-wt% KTPB/CsTPB slurry. Residual NaTPB decomposes to form benzene, which is retained by the waste slurry. The retained benzene is also readily released from the waste during subsequent waste processing. While the release of benzene certainly poses flammability and toxicological safety concerns, the magnitude of the hazard depends on the rate of release. Currently, the mechanisms controlling the benzene release rates are not well understood, and predictive models for estimating benzene release rates are not available. The overall purpose of this study is to obtain quantitative measurements of benzene release rates from a series of ITP slurry simulants. This information will become a basis for developing a quantitative mechanistic model of benzene release rates. The transient benzene release rate was measured from the surface of various ITP slurry (solution) samples mixed with benzene. The benzene release rate was determined by continuously purging the headspace of a sealed sample vessel with an inert gas (nitrogen) and analyzing that purged headspace vapor for benzene every minute

  13. Benzene degradation in a denitrifying biofilm reactor: activity and microbial community composition.

    Science.gov (United States)

    van der Waals, Marcelle J; Atashgahi, Siavash; da Rocha, Ulisses Nunes; van der Zaan, Bas M; Smidt, Hauke; Gerritse, Jan

    2017-06-01

    Benzene is an aromatic compound and harmful for the environment. Biodegradation of benzene can reduce the toxicological risk after accidental or controlled release of this chemical in the environment. In this study, we further characterized an anaerobic continuous biofilm culture grown for more than 14 years on benzene with nitrate as electron acceptor. We determined steady state degradation rates, microbial community composition dynamics in the biofilm, and the initial anaerobic benzene degradation reactions. Benzene was degraded at a rate of 0.15 μmol/mg protein/day and a first-order rate constant of 3.04/day which was fourfold higher than rates reported previously. Bacteria belonging to the Peptococcaceae were found to play an important role in this anaerobic benzene-degrading biofilm culture, but also members of the Anaerolineaceae were predicted to be involved in benzene degradation or benzene metabolite degradation based on Illumina MiSeq analysis of 16S ribosomal RNA genes. Biomass retention in the reactor using a filtration finger resulted in reduction of benzene degradation capacity. Detection of the benzene carboxylase encoding gene, abcA, and benzoic acid in the culture vessel indicated that benzene degradation proceeds through an initial carboxylation step.

  14. The state of benzene in TIP slurry using nuclear magnetic resonance measurements

    International Nuclear Information System (INIS)

    Dworjanyn, L.O.

    1997-01-01

    Nuclear Magnetic Resonance (NMR) measurements on In-Tank Precipitation (ITP) simulated potassium tetraphenylborate (KTPB) slurries at Pacific Northwest National Laboratory have been completed. Most measurements were made on 4 wt percent KTPB slurry in 4 to 5 molar sodium salt solution. Liquid benzene was added volumetrically to the slurry in 25-mL vials and agitated to create a suspension. Earlier tests using dyed benzene showed that benzene remains suspended permanently in the slurry and the only visible change is overall slurry settling. Gentle vial agitation restores the original suspension state. To simulate in-situ uniformly dispersed benzene, benzene/KTPB samples were homogenized using a high speed rotor/stator biological homogenizer. Photomicrographs using homogenized samples containing dyed benzene showed no residual benzene droplets and fairly uniform coloration of the KTPB solids structure. All benzene concentration estimates are based on benzene addition since there is no available analytical method for benzene in slurry. Benzene losses could be significant, particularly at low concentrations and during homogenization

  15. The state of benzene in TIP slurry using nuclear magnetic resonance measurements

    Energy Technology Data Exchange (ETDEWEB)

    Dworjanyn, L.O.

    1997-11-14

    Nuclear Magnetic Resonance (NMR) measurements on In-Tank Precipitation (ITP) simulated potassium tetraphenylborate (KTPB) slurries at Pacific Northwest National Laboratory have been completed. Most measurements were made on 4 wt percent KTPB slurry in 4 to 5 molar sodium salt solution. Liquid benzene was added volumetrically to the slurry in 25-mL vials and agitated to create a suspension. Earlier tests using dyed benzene showed that benzene remains suspended permanently in the slurry and the only visible change is overall slurry settling. Gentle vial agitation restores the original suspension state. To simulate in-situ uniformly dispersed benzene, benzene/KTPB samples were homogenized using a high speed rotor/stator biological homogenizer. Photomicrographs using homogenized samples containing dyed benzene showed no residual benzene droplets and fairly uniform coloration of the KTPB solids structure. All benzene concentration estimates are based on benzene addition since there is no available analytical method for benzene in slurry. Benzene losses could be significant, particularly at low concentrations and during homogenization.

  16. Annoyance Caused by Noise and Air Pollution during Pregnancy: Associated Factors and Correlation with Outdoor NO2 and Benzene Estimations

    Directory of Open Access Journals (Sweden)

    Ana Fernández-Somoano

    2015-06-01

    Full Text Available This study aimed to describe the degree of annoyance among pregnant women in a Spanish cohort and to examine associations with proximity to traffic, NO2 and benzene exposure. We included 2457 participants from the Spanish Childhood and Environment study. Individual exposures to outdoor NO2 and benzene were estimated, temporally adjusted for pregnancy. Interviews about sociodemographic variables, noise and air pollution were carried out. Levels of annoyance were assessed using a scale from 0 (none to 10 (strong and unbearable; a level of 8 to 10 was considered high. The reported prevalence of high annoyance levels from air pollution was 11.2% and 15.0% from noise; the two variables were moderately correlated (0.606. Significant correlations between NO2 and annoyance from air pollution (0.154 and that from noise (0.181 were observed. Annoyance owing to noise and air pollution had a low prevalence in our Spanish population compared with other European populations. Both factors were associated with proximity to traffic. In multivariate models, annoyance from air pollution was related to NO2, building age, and country of birth; annoyance from noise was only related to the first two. The health burden of these exposures can be increased by stress caused by the perception of pollution sources.

  17. Annoyance Caused by Noise and Air Pollution during Pregnancy: Associated Factors and Correlation with Outdoor NO2 and Benzene Estimations

    Science.gov (United States)

    Fernández-Somoano, Ana; Llop, Sabrina; Aguilera, Inmaculada; Tamayo-Uria, Ibon; Martínez, María Dolores; Foraster, Maria; Ballester, Ferran; Tardón, Adonina

    2015-01-01

    This study aimed to describe the degree of annoyance among pregnant women in a Spanish cohort and to examine associations with proximity to traffic, NO2 and benzene exposure. We included 2457 participants from the Spanish Childhood and Environment study. Individual exposures to outdoor NO2 and benzene were estimated, temporally adjusted for pregnancy. Interviews about sociodemographic variables, noise and air pollution were carried out. Levels of annoyance were assessed using a scale from 0 (none) to 10 (strong and unbearable); a level of 8 to 10 was considered high. The reported prevalence of high annoyance levels from air pollution was 11.2% and 15.0% from noise; the two variables were moderately correlated (0.606). Significant correlations between NO2 and annoyance from air pollution (0.154) and that from noise (0.181) were observed. Annoyance owing to noise and air pollution had a low prevalence in our Spanish population compared with other European populations. Both factors were associated with proximity to traffic. In multivariate models, annoyance from air pollution was related to NO2, building age, and country of birth; annoyance from noise was only related to the first two. The health burden of these exposures can be increased by stress caused by the perception of pollution sources. PMID:26095869

  18. Annoyance Caused by Noise and Air Pollution during Pregnancy: Associated Factors and Correlation with Outdoor NO2 and Benzene Estimations.

    Science.gov (United States)

    Fernández-Somoano, Ana; Llop, Sabrina; Aguilera, Inmaculada; Tamayo-Uria, Ibon; Martínez, María Dolores; Foraster, Maria; Ballester, Ferran; Tardón, Adonina

    2015-06-18

    This study aimed to describe the degree of annoyance among pregnant women in a Spanish cohort and to examine associations with proximity to traffic, NO2 and benzene exposure. We included 2457 participants from the Spanish Childhood and Environment study. Individual exposures to outdoor NO2 and benzene were estimated, temporally adjusted for pregnancy. Interviews about sociodemographic variables, noise and air pollution were carried out. Levels of annoyance were assessed using a scale from 0 (none) to 10 (strong and unbearable); a level of 8 to 10 was considered high. The reported prevalence of high annoyance levels from air pollution was 11.2% and 15.0% from noise; the two variables were moderately correlated (0.606). Significant correlations between NO2 and annoyance from air pollution (0.154) and that from noise (0.181) were observed. Annoyance owing to noise and air pollution had a low prevalence in our Spanish population compared with other European populations. Both factors were associated with proximity to traffic. In multivariate models, annoyance from air pollution was related to NO2, building age, and country of birth; annoyance from noise was only related to the first two. The health burden of these exposures can be increased by stress caused by the perception of pollution sources.

  19. GC/MS analyses of fractionated extraction of Shenfu coal with CS{sub 2}, n-hexane, benzene

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X.; Wei, X. [Xi' an University of Science and Technology, Xi' an (China). Department of Chemistry and Chemical Engineering

    2008-12-15

    Shenfu coal was extracted with CS{sub 2}, n-hexane and benzene sequentially. The extracts were analyzed with GC/MS. It is shown that group separation of soluble organic compounds in the coal can be achieved by fractionated extraction using different solvents. The main components in the CS{sub 2} soluble fraction from Shenfu coal are alkyl-substituted arenes. Aliphatic hydrocarbons are overwhelmingly predominant in the n-hexane-soluble fraction. Di- to tricyclic aromatic hydrocarbons are identified in the benzene-soluble fraction. The molecular structures detection of 2, 4, 6-trichlorobenzenamine and 3, 3{prime}, 4, 4 {prime}, 5, 5 {prime}-hexachloro-1, 1 {prime}-biphenyl and 2-chlorocyclohexanol provide information on the forms of existence of chlorine in coal. 8 refs., 3 figs., 1 tab.

  20. Occupational exposure to solvents and bladder cancer

    DEFF Research Database (Denmark)

    Hadkhale, Kishor; Martinsen, Jan Ivar; Weiderpass, Elisabete

    2017-01-01

    The objective of the study was to assess the relationship between exposure to selected solvents and the risk of bladder cancer. This study is based on the Nordic Occupational Cancer (NOCCA) database and comprises 113,343 cases of bladder cancer diagnosed in Finland, Iceland, Norway and Sweden...... of occupational exposure to trichloroethylene, perchloroethylene, aromatic hydrocarbon solvents, benzene and toluene and the risk of bladder cancer....

  1. Mechanisms of free radical chemistry and biochemistry of benzene

    International Nuclear Information System (INIS)

    Karam, L.R.; Simic, M.G.

    1989-01-01

    o-Tyrosine (o-Tyr) was used as a specific biomarker for OH radicals generated in biosystems. Specificity of o-Tyr as an OH biomarker was based on previous studied in systems exposed to ionizing radiations. Fresh muscle tissue incubated with benzene for 1 hr at 38 degree C exhibits formation of o-Tyr as seen in the cases of ethanol- and carbon tetrachloride-exposed systems. Gas chromatography/mass spectrometry selective ion monitoring measurements of o-Tyr yields in chicken breast muscle incubated with water or benzene indicate levels of less than 0.1 ppm and 3.0 ± 0.5 ppm of o-Tyr, respectively. Formation of OH is presumed to originate via a Haber-Weiss reaction of H 2 O 2 with Fe (II) preceded by the formation of O 2 and H 2 O 2 from distorted mitochondria

  2. 1,4-Dialkynylbutatrienes: synthesis, stability, and perspectives in the chemistry of carbo-benzenes.

    Science.gov (United States)

    Maraval, Valérie; Leroyer, Léo; Harano, Aya; Barthes, Cécile; Saquet, Alix; Duhayon, Carine; Shinmyozu, Teruo; Chauvin, Remi

    2011-04-26

    The π-electron-rich C(8)-conjugated sequence of 1,4-dialkynylbutatrienes is identified as a fragile and fascinating motif occurring in carbo-benzene derivatives, and in Diederich's 1,4-bis(arylethynyl)- or 1,4-bis(triisopropylsilylethynyl)butatriene "capped" representatives, in particular, in tetraalkynylbutatriene. The family of symmetrical 1,4-dialkynylbutatrienes (E-C≡C)RC=C=C=CR(C≡C-E) is extended to functional caps (E=H, CH(3), C≡CPh, CPh=CHBr, or CPh=CBr(2)) with non-alkynyl substituents at the sp(2) vertices (R=Ph or CF(3)). The targets were selected for their potential in appealing retrosynthetic routes to carbo-benzenes, in which the aromatic C(18) macrocycle would be directly generated by sequential metathesis or reductive coupling processes. The functional 1,4-dialkynylbutrienes were synthesized by either classical methods used for the preparation of generic butatrienes (R'Li/CuX-mediated reductive coupling of gem-dihaloenynes or SnCl(2)/HCl-mediated reduction of 3,6-dioxy-octa-1,4,7-triyne precursors). Their spectroscopic and electrochemical properties are compared and analyzed on the basis of the relative extent of total conjugation. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. 2-Phenylimidazolium hemi(benzene-1,3-dicarboxylate monohydrate

    Directory of Open Access Journals (Sweden)

    Wen-Yu Zhang

    2011-08-01

    Full Text Available The asymmetric unit of the title compound, C9H9N2+·0.5C8H4O4−·H2O, contains one 2-phenylimidazolium cation, half a benzene-1,3-dicarboxylate anion and one water molecule. In the crystal, components are connected by N—H...O and O—H...O hydrogen-bonding interactions into a three-dimensional network.

  4. Synthesis of (+)-Pancratistatins via Catalytic Desymmetrization of Benzene.

    Science.gov (United States)

    Hernandez, Lucas W; Pospech, Jola; Klöckner, Ulrich; Bingham, Tanner W; Sarlah, David

    2017-11-08

    A concise synthesis of (+)-pancratistatin and (+)-7-deoxypancratistatin from benzene using an enantioselective, dearomative carboamination strategy has been achieved. This approach, in combination with the judicious choice of subsequent olefin-type difunctionalization reactions, permits rapid and controlled access to a hexasubstituted core. Finally, minimal use of intermediary steps as well as direct, late stage C-7 hydroxylation provides both natural products in six and seven operations.

  5. Lithium Mediated Benzene Adsorption on Graphene and Graphene Nanoribbons

    OpenAIRE

    Krepel, Dana; Hod, Oded

    2013-01-01

    The anchoring of benzene molecules on lithium adsorption sites at the surface of graphene and nanoribbons thereof are investigated. The effects of adsorbate densities, specific adsorption locations, and spin states on the structural stability and electronic properties of the underlying graphene derivatives are revealed. At sufficiently high densities, bare lithium adsorption turns armchair graphene nanoribbons metallic and their zigzag counterparts half-metallic due to charge transfer from th...

  6. Amidine Sulfonamides and Benzene Sulfonamides: Synthesis and Their Biological Evaluation

    OpenAIRE

    Muhammad Abdul Qadir; Mahmood Ahmed; Hina Aslam; Sadia Waseem; Muhammad Imtiaz Shafiq

    2015-01-01

    New amidine and benzene sulfonamide derivatives were developed and structures of the new products were confirmed by elemental and spectral analysis (FT-IR, ESI-MS, 1HNMR, and 13CNMR). In vitro, developed compounds were screened for their antibacterial and antifungal activities against medically important bacterial strains, namely, S. aureus, B. subtilis, and E. coli, and fungi, namely, A. flavus, A. parasiticus, and A. sp. The antibacterial and antifungal activities have been determined by me...

  7. Catalytic transformation of methyl benzenes over zeolite catalysts

    KAUST Repository

    Al-Khattaf, S.

    2011-02-01

    Catalytic transformation of three methyl benzenes (toluene, m-xylene, and 1,2,4-trimethyl benzene) has been investigated over ZSM-5, TNU-9, mordenite and SSZ-33 catalysts in a novel riser simulator at different operating conditions. Catalytic experiments were carried out in the temperature range of 300-400 °C to understand the transformation of these alkyl benzenes over large pore (mordenite and SSZ-33) in contrast to medium-pore (ZSM-5 and TNU-9) zeolite-based catalysts. The effect of reaction conditions on the isomerization to disproportionation product ratio, distribution of trimethylbenzene (TMB) isomers, and p-xylene/o-xylene ratios are reported. The sequence of reactivity of the three alkyl benzenes depends upon the pore structure of zeolites. The zeolite structure controls primarily the diffusion of reactants and products while the acidity of these zeolites is of a secondary importance. In the case of medium pore zeolites, the order of conversion was m-xylene > 1,2,4-TMB > toluene. Over large pore zeolites the order of reactivity was 1,2,4-TMB > m-xylene > toluene for SSZ-33 catalyst, and m-xylene ∼ 1,2,4-TMB > toluene over mordenite. Significant effect of pore size between ZSM-5 and TNU-9 was observed; although TNU-9 is also 3D 10-ring channel system, its slightly larger pores compared with ZSM-5 provide sufficient reaction space to behave like large-pore zeolites in transformation of aromatic hydrocarbons. We have also carried out kinetic studies for these reactions and activation energies for all three reactants over all zeolite catalysts under study have been calculated. © 2011 Elsevier B.V.

  8. Gestational exposure to volatile organic compounds (VOCs) in Northeastern British Columbia, Canada: A pilot study.

    Science.gov (United States)

    Caron-Beaudoin, Élyse; Valter, Naomi; Chevrier, Jonathan; Ayotte, Pierre; Frohlich, Katherine; Verner, Marc-André

    2018-01-01

    Northeastern British Columbia (Canada) is an area of intense hydraulic fracturing for unconventional natural gas exploitation. There have been multiple reports of air and water contamination by volatile organic compounds in the vicinity of gas wells. Although these chemicals are known developmental toxicants, no biomonitoring effort has been carried out in the region. To evaluate gestational exposure to benzene and toluene in the Peace River Valley, Northeastern British Columbia (Canada). Urine samples were collected over five consecutive days from 29 pregnant women. Metabolites of benzene (s-phenylmercapturic acid (S-PMA) and trans, trans-muconic acid (t,t-MA)) and toluene (s-benzylmercapturic acid (S-BMA)) were measured in pooled urine samples from each participant. Levels of benzene metabolites were compared to those from the general Canadian population and from a biomonitoring study of residents from an area of active gas exploitation in Pavillion, Wyoming (USA). Levels measured in participants from the two recruitment sites, and self-identifying as Indigenous or non-Indigenous, were also compared. Whereas the median S-PMA level (0.18μg/g creatinine) in our study was similar to that in the general Canadian population, the median t,t-MA level (180μg/g creatinine) was approximately 3.5 times higher. Five women had t,t-MA levels above the biological exposure index® proposed by the American Conference of Governmental Industrial Hygienists. The median urinary S-BMA level in our pilot study was 7.00μg/g creatinine. Urinary metabolite levels were slightly higher in self-identifying Indigenous women, but this difference was only statistically significant for S-PMA. Urinary t,t-MA levels, but not S-PMA levels, measured in our study are suggestive of a higher benzene exposure in participating pregnant women from the Peace River Valley than in the general Canadian population. Given the small sample size and limitations of t,t-MA measurements (e.g., non

  9. Adsorption Of Water And Benzene Vapour In Mesoporous Materials

    Directory of Open Access Journals (Sweden)

    Paulina Taba

    2008-11-01

    Full Text Available Mesoporous materials have attracted the attention of many researchers due to the potential applications promised by the materials. This article discusses adsorption of water and benzene vapour in mesoporous materials (mesoporous silica: MCM-41, MCM-48 and their modification. MCM-41 and MCM-48 were synthesized hydrothermally at 100 oC using cethyltrimethylammonium chloride or dodecyltrimethylammonium bromide for MCM-41 (C16 or MCM-41 (C12 respectively and a mixture of cethyltrimethylammonium bromide and Triton X-100 for MCM-48 as templates. Their modifications were conducted by silylation of MCM-41 (C16 and MCM-48 with trimethylchloro silane (MCM16-TMCS and MCM48-TMCS and t-butyldimethylchloro silane (MCM16-TBDMCS and MCM48-TBDMCS. Results showed that MCM-41 and MCM-48 materials had hydrophobic features which were shown in the small amount of water adsorption at low P/P0. The hydrophobicity of samples used in this study decrease in the sequence: MCM-41 (C16 > MCM-48 > MCM-41 (C12. The hydrophobicity increased when MCM-41 and MCM-48 were silylated with TMCS or TBDMCS. All unsilylated MCM materials show higher affinity to benzene at low P/P0 than the silylated samples. The results of water and benzene adsorption showed that silylated samples are promising candidates as selective adsorbents for organic compounds.

  10. Anaerobic Degradation of Benzene and Polycyclic Aromatic Hydrocarbons.

    Science.gov (United States)

    Meckenstock, Rainer U; Boll, Matthias; Mouttaki, Housna; Koelschbach, Janina S; Cunha Tarouco, Paola; Weyrauch, Philip; Dong, Xiyang; Himmelberg, Anne M

    2016-01-01

    Aromatic hydrocarbons such as benzene and polycyclic aromatic hydrocarbons (PAHs) are very slowly degraded without molecular oxygen. Here, we review the recent advances in the elucidation of the first known degradation pathways of these environmental hazards. Anaerobic degradation of benzene and PAHs has been successfully documented in the environment by metabolite analysis, compound-specific isotope analysis and microcosm studies. Subsequently, also enrichments and pure cultures were obtained that anaerobically degrade benzene, naphthalene or methylnaphthalene, and even phenanthrene, the largest PAH currently known to be degradable under anoxic conditions. Although such cultures grow very slowly, with doubling times of around 2 weeks, and produce only very little biomass in batch cultures, successful proteogenomic, transcriptomic and biochemical studies revealed novel degradation pathways with exciting biochemical reactions such as for example the carboxylation of naphthalene or the ATP-independent reduction of naphthoyl-coenzyme A. The elucidation of the first anaerobic degradation pathways of naphthalene and methylnaphthalene at the genetic and biochemical level now opens the door to studying the anaerobic metabolism and ecology of anaerobic PAH degraders. This will contribute to assessing the fate of one of the most important contaminant classes in anoxic sediments and aquifers. © 2016 S. Karger AG, Basel.

  11. Adsorption of Benzene by “Green” functionalization of Montmorillonite

    Directory of Open Access Journals (Sweden)

    Anjum Hirra

    2018-01-01

    Full Text Available The capacity of organically modified Montmorillonite (MMT clay to adsorb nonpolar organic compound (benzene in an aqueous solution, was investigated under the batch process. MMT was pretreated (centrifuged and then functionalized with green intercalating agent i.e. 1-hexyl-3-methyl imadazolium chloride [HMim][Cl]. The characterization through Fourir Transoform Infrared Spectroscopy (FTIR, Differential Scanning Calorimeter (DSC and Field Emission Scanning Electron Microscope (FE-SEM confirmed the presence of the oxygen containing functional groups, changes in melting point and variation in the morphological properties. The governing parameters for the sorption of benzene such as the effect of contact time, pH, adsorbent dose and rotation were studied. The kinetic data conformed to pseuodo 2nd order kinetic model and the isotherm experimental data were a better fit to Langmuir model with maximum adsorption capacity of 588.23mg/g under experimental conditions. Overall, MMT intercalated with 1-hexyl-3-methyl imadazolium chloride is a promising environmental friendly adsorbent for the abatement of benzene in an aqueous solution.

  12. STABILITY OF HEMOGLOBIN AND ALBUMIN ADDUCTS OF BENZENE OXIDE AND 1,4-BENZOQUINONE AFTER ADMINISTRATION OF BENZENE TO F344 RATS

    Science.gov (United States)

    The stability of cysteinyl adducts of benzene oxide (BO) and mono-S-substituted cysteinyl adducts of 1,4-benzoquinone (1,4-BQ) was investigated in both hemoglobin (Hb) and albumin (Alb) following administration of a single oral dose of 400 mg [U-14C/13C6]benzene/kg body weight ...

  13. The benzene metabolite para-benzoquinone is genotoxic in human, phorbol-12-acetate-13-myristate induced, peripheral blood mononuclear cells at low concentrations.

    Science.gov (United States)

    Westphal, Götz Alexander; Bünger, Jürgen; Lichey, Nadine; Taeger, Dirk; Mönnich, Angelika; Hallier, Ernst

    2009-07-01

    Benzene is one of the most prominent occupational and environmental pollutants. The substance is a proven human carcinogen that induces hematologic malignancies in humans, probably at even low doses. Yet knowledge of the mechanisms leading to benzene-induced carcinogenesis is still incomplete. Benzene itself is not genotoxic. The generation of carcinogenic metabolites involves the production of oxidized intermediates such as catechol, hydroquinone and para-benzoquinone (p-BQ) in the liver. Further activation to the ultimate carcinogenic intermediates is most probably catalyzed by myeloperoxidase (MPO). Yet the products of the MPO pathway have not been identified. If an oxidized benzene metabolite such as p-BQ was actually the precursor for the ultimate carcinogenic benzene metabolite and further activation proceeds via MPO mediated reactions, it should be possible to activate p-BQ to a genotoxic compound in vitro. We tested this hypothesis with phorbol-12-acetate-13-myristate (PMA) activated peripheral blood cells exposed to p-BQ, using the cytokinesis-block micronucleus test. Addition of 20-28 ng/ml PMA caused a significant increase of micronuclei at low and non-cytotoxic p-BQ concentrations between 0.04 and 0.2 microg/ml (0.37-1.85 microM). Thus with PMA or p-BQ alone no reproducible elevation of micronuclei was seen up to toxic concentrations. PMA and p-BQ induce micronuclei when administered jointly. Our results add further support to the hypothesis that MPO is a key enzyme in the activation of benzene.

  14. Evaluation of three types of passive samplers for measuring 1,3-butadiene and benzene at workplaces.

    Science.gov (United States)

    Strandberg, Bo; Bergemalm-Rynell, Kerstin; Sallsten, Gerd

    2014-05-01

    1,3-Butadiene and benzene are common pollutants in both workplace and ambient air and have received attention for their adverse effects on human health. In exposure studies, simple and sensitive personal monitoring methods are preferable. Thermal desorption passive samplers seem optimal for this purpose, although in occupational studies chemical desorption samplers have been used more often. This may be because their utility for monitoring occupational atmospheres has not been thoroughly validated. Therefore, we evaluated thermal desorption passive samplers containing Carbopack X adsorbent from three manufacturers: Perkin Elmer, SKC-Ultra and Radiello. The uptake rates of benzene and 1,3-butadiene by these samplers were determined over 4 h or 8 h in exposure chamber studies at three concentrations likely to be found in occupational air. The samplers were also tested in a field study, at a petroleum refinery. The results were analyzed using multiple linear regression, and intra-class correlation coefficients (ICCs) were calculated to compare uptake rates of the three passive samplers to those of an active sampler. The three samplers had similar and acceptable accuracy (ICC≥0.9) for measuring benzene concentrations in the field environments, but only the Perkin Elmer sampler gave acceptable ICC values (∼0.85) for 1,3-butadiene over a full 8 h working shift in the field test. The results indicate that passive thermal desorption monitors can provide considerably lower limits of detection than chemical desorption monitors after 4-8 h sampling time, even down to environmental background concentrations, enabling comparison with measurements in ambient air.

  15. A retrospective cohort study of cause-specific mortality and incidence of hematopoietic malignancies in Chinese benzene-exposed workers.

    Science.gov (United States)

    Linet, Martha S; Yin, Song-Nian; Gilbert, Ethel S; Dores, Graça M; Hayes, Richard B; Vermeulen, Roel; Tian, Hao-Yuan; Lan, Qing; Portengen, Lutzen; Ji, Bu-Tian; Li, Gui-Lan; Rothman, Nathaniel

    2015-11-01

    Benzene exposure has been causally linked with acute myeloid leukemia (AML), but inconsistently associated with other hematopoietic, lymphoproliferative and related disorders (HLD) or solid tumors in humans. Many neoplasms have been described in experimental animals exposed to benzene. We used Poisson regression to estimate adjusted relative risks (RR) and the likelihood ratio statistic to derive confidence intervals for cause-specific mortality and HLD incidence in 73,789 benzene-exposed compared with 34,504 unexposed workers in a retrospective cohort study in 12 cities in China. Follow-up and outcome assessment was based on factory, medical and other records. Benzene-exposed workers experienced increased risks for all-cause mortality (RR = 1.1, 95% CI = 1.1, 1.2) due to excesses of all neoplasms (RR = 1.3, 95% CI = 1.2, 1.4), respiratory diseases (RR = 1.7, 95% CI = 1.2, 2.3) and diseases of blood forming organs (RR = ∞, 95% CI = 3.4, ∞). Lung cancer mortality was significantly elevated (RR = 1.5, 95% CI = 1.2, 1.9) with similar RRs for males and females, based on three-fold more cases than in our previous follow-up. Significantly elevated incidence of all myeloid disorders reflected excesses of myelodysplastic syndrome/acute myeloid leukemia (RR = 2.7, 95% CI = 1.2, 6.6) and chronic myeloid leukemia (RR = 2.5, 95% CI = 0.8, 11), and increases of all lymphoid disorders included excesses of non-Hodgkin lymphoma (RR = 3.9, 95%CI = 1.5, 13) and all lymphoid leukemia (RR = 5.4, 95%CI = 1.0, 99). The 28-year follow-up of Chinese benzene-exposed workers demonstrated increased risks of a broad range of myeloid and lymphoid neoplasms, lung cancer, and respiratory diseases and suggested possible associations with other malignant and non-malignant disorders. © 2015 UICC.

  16. Utilization of alternative fuels and materials in cement kiln towards emissions of benzene, toluene, ethyl-benzene and xylenes (BTEX

    Directory of Open Access Journals (Sweden)

    Muliane Ulfi

    2018-01-01

    Full Text Available Co-processing in cement industry has benefits for energy conservation and waste recycling. Nevertheless, emissions of benzene, toluene, ethyl-benzene, and xylenes (BTEX tend to increase compared to a non co-processing kiln. A study was conducted in kiln feeding solid AFR (similar to municipal solid waste, MSW having production capacity 4600-ton clinker/day (max. 5000 ton/day and kiln feeding biomass having production capacity 7800-ton clinker/day (max. 8000 ton/day. The concentration of VOCs emissions tends to be higher at the raw mill on rather than the raw mill off. At the raw mill on, concentration of total volatile organic carbon (VOCs emission from cement kiln stack feeding Solid AFR 1, biomass, Solid AFR 2, and mixture of Solid AFR and biomass is 16.18 mg/Nm3, 16.15 mg/Nm3, 9.02 mg/Nm3, and 14.11 mg/Nm3 respectively. The utilization of biomass resulted in the lower fraction of benzene and the higher fraction of xylenes in the total VOCs emission. Operating conditions such as thermal substitution rate, preheater temperature, and kiln speed are also likely to affect BTEX emissions.

  17. A mechanistic study on the reaction pathways leading to benzene and naphthalene in cellulose vapor phase cracking

    International Nuclear Information System (INIS)

    Norinaga, Koyo; Yang, Huamei; Tanaka, Ryota; Appari, Srinivas; Iwanaga, Keita; Takashima, Yuka; Kudo, Shinji; Shoji, Tetsuya; Hayashi, Jun-ichiro

    2014-01-01

    The reaction pathways leading to aromatic hydrocarbons such as benzene and naphthalene in gas-phase reactions of multi-component mixtures derived from cellulose fast pyrolysis were studied both experimentally and numerically. A two-stage tubular reactor was used for evaluating the reaction kinetics of secondary vapor phase cracking of the nascent pyrolysates at temperature ranging from 400 to 900 °C, residence time from 0.2 to 4.3 s, and at 241 kPa. The products of alkyne and diene were identified from the primary pyrolysis of cellulose even at low temperature range 500–600 °C. These products include acetylene, propyne, propadiene, vinylacetylene, and cyclopentadiene. Experiments were also numerically validated by a detailed chemical kinetic model consisting of more than 8000 elementary step-like reactions with over 500 chemical species. Acceptable capabilities of the kinetic model in predicting concentration profiles of the products enabled us to assess reaction pathways leading to benzene and naphthalene via the alkyne and diene from primary pyrolysates of cellulose. C 3 alkyne and diene are primary precursors of benzene at 650 °C, while combination of ethylene and vinylacetylene produces benzene dominantly at 850 °C. Cyclopentadiene is a prominent precursor of naphthalene. Combination of acetylene with propyne or allyl radical leads to the formation of cyclopentadiene. Furan and acrolein are likely important alkyne precursors in cellulose pyrolysis at low temperature, whereas dehydrogenations of olefins are major route to alkyne at high temperatures. - Highlights: • Analytical pyrolysis experiments provided data for kinetic modeling. • Detailed chemical kinetic model was used and evaluated. • Alkyne and diene were important intermediates for aromatic hydrocarbon formation. • Reaction pathways leading to aromatic hydrocarbons were proposed

  18. Benzene adsorption and hydrogenation on Pd-Ru alloy by pulse chromatography

    International Nuclear Information System (INIS)

    Dobrokhotov, V.G.; Pavlova, L.F.; Gryaznov, V.M.

    1983-01-01

    Pulse chromatography has been applied to investigate benzene adsorption and hydrogenation on the Walls of a capillary of the Pd-6% Ru alloy at different hydrogen contents in the alloy and various methods of hydrogen supply: as a mixture with benzene vapors or by diffusion through the walls of the capillary. It is stated that reversible adsorption of benzene vapors on the Pd-6% Ru alloy at 303 K under the conditions of the β-phase existence in the alloy-hydrogen system does not change whereas in the region of the α-phase existence it slightly increases with a growth of hydrogen pressure. Strongly adsorbed benzene occupies approximately 7% of the surface. Only strongly adsorbed benzene is hydrogenated on the α-phase of the alloy-hydrogen system. Hydrogen supply to the hydrogenation zone by diffusion throUgh the alloy results in supersaturation of the surface active in the reaction of benzene hydrogenation with a chemisorbed hydrogen form

  19. Structural Degradation and Swelling of Lipid Bilayer under the Action of Benzene.

    Science.gov (United States)

    Odinokov, Alexey; Ostroumov, Denis

    2015-12-03

    Benzene and other nonpolar organic solvents can accumulate in the lipid bilayer of cellular membranes. Their effect on the membrane structure and fluidity determines their toxic properties and antibiotic action of the organic solvents on the bacteria. We performed molecular dynamics simulations of the interaction of benzene with the dimyristoylphosphatidylcholine (DMPC) bilayer. An increase in the membrane surface area and fluidity was clearly detected. Changes in the acyl chain ordering, tilt angle, and overall bilayer thickness were, however, much less marked. The dependence of all computed quantities on the benzene content showed two regimes separated by the solubility limit of benzene in water. When the amount of benzene exceeded this point, a layer of almost pure benzene started to grow between the membrane leaflets. This process corresponds to the nucleation of a new phase and provides a molecular mechanism for the mechanical rupture of the bilayer under the action of nonpolar compounds.

  20. Linking exposure to environmental pollutants with biological effects

    DEFF Research Database (Denmark)

    Sørensen, Mette; Autrup, Herman; Møller, Peter

    2003-01-01

    exposure to PM(2.5), nitrogen dioxide (NO(2)) and benzene has been measured in groups of 40-50 subjects. Measured biomarkers included 1-hydroxypyrene, benzene metabolites (phenylmercapturic acid (PMA) and trans-trans-muconic acid (ttMA)), 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) in urine, DNA strand....... With respect to exposure to PM, biomarkers of oxidative damage showed significant positive association with the individual exposure. Thus, 8-oxodG in lymphocyte DNA and markers of oxidative damage to lipids and protein in plasma associated with PM(2.5) exposure. Several types of DNA damage showed seasonal......, biological effects of air pollutants appear mainly related to oxidative stress via personal exposure and not to urban background levels. Future developments include personal time-resolved monitors for exposure to ultrafine PM and PM(2.5,) use of GPS, as well as genomics and proteomics based biomarkers....

  1. A comprehensive assessment of mercury exposure in penguin populations throughout the Southern Hemisphere: Using trophic calculations to identify sources of population-level variation.

    Science.gov (United States)

    Brasso, Rebecka L; Chiaradia, André; Polito, Michael J; Raya Rey, Andrea; Emslie, Steven D

    2015-08-15

    The wide geographic distribution of penguins (Order Sphenisciformes) throughout the Southern Hemisphere provided a unique opportunity to use a single taxonomic group as biomonitors of mercury among geographically distinct marine ecosystems. Mercury concentrations were compared among ten species of penguins representing 26 geographically distinct breeding populations. Mercury concentrations were relatively low (⩽2.00ppm) in feathers from 18/26 populations considered. Population-level differences in trophic level explained variation in mercury concentrations among Little, King, and Gentoo penguin populations. However, Southern Rockhopper and Magellanic penguins breeding on Staten Island, Tierra del Fuego, had the highest mercury concentrations relative to their conspecifics despite foraging at a lower trophic level. The concurrent use of stable isotope and mercury data allowed us to document penguin populations at the greatest risk of exposure to harmful concentrations of mercury as a result of foraging at a high trophic level or in geographic 'hot spots' of mercury availability. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Establishment of a Methanogenic Benzene-Degrading Culture and its Implication in Bioremediation

    Science.gov (United States)

    Qiao, W.; Luo, F.; Bawa, N.; Guo, S.; Ye, S.; Edwards, E.

    2017-12-01

    Benzene is a known human carcinogen and it is a common pollutant in groundwater, mainly resulting from petrochemical industry. Anaerobic degradation of benzene has significant advantages over aerobic processes for in situ bioremediation. In this study, new methanogenic and sulfate-reducing benzene degrading cultures have been enriched. Microbial community composition was characterized with two other previously established benzene-degrading cultures, and their potential use in bioaugmentation is investigated. In this study, a lab microcosm study was conducted anaerobically with contaminated soil and groundwater from a former chemical plant. Benzene degradation was observed in the presence of co-contaminants and electron donor. Through repetitive amendment of benzene, two enrichment cultures have been developed under sulfate and methanogenic conditions. Results from DNA amplicon sequencing and qPCR analysis revealed that an organism similar to previously described benzene-degrading Deltaproteobacterium has been enriched. The microbial community of this culture was compared with other two methanogenic benzene-degrading enrichment cultures that were derived from an oil refinery and a decommissioned gasoline station, and have been maintained for decades. Deltaproteobacterium ORM2-like microbes were dominate in all enrichment cultures, which brought to light benzene-degrading microbes, ORM2 were enriched under different geological conditions distributed around the world. The relative abundance of methanogens was much lower compared to previously established cultures, although substantial amount of methane was produced. The peripheral organisms also vary. To investigate effectiveness of using ORM2-dominant enrichment cultures in bioremediation, microcosm studies were set up using contaminated materials, and a ORM2-dominating methanogenic benzene-degrading culture was used for bioaugmentation. Results revealed that benzene degradation was speeded up under methanogenic or

  3. Stability, structural and electronic properties of benzene molecule adsorbed on free standing Au layer

    Energy Technology Data Exchange (ETDEWEB)

    Katoch, Neha, E-mail: nehakatoch2@gmail.com; Kapoor, Pooja; Sharma, Munish; Ahluwalia, P. K. [Physics Department, Himachal Pradesh University, Shimla, Himachal Pradesh, India 171005 (India); Kumar, Ashok [Center for Physical Sciences, School of Basic and Applied Sciences, Central University of Punjab, Bathinda, India, 151001 (India)

    2016-05-23

    We report stability and electronic properties of benzene molecule adsorbed on the Au atomic layer within the framework of density function theory (DFT). Horizontal configuration of benzene on the top site of Au monolayer prefers energetically over other studied configurations. On the adsorption of benzene, the ballistic conductance of Au monolayer is found to decrease from 4G{sub 0} to 2G{sub 0} suggesting its applications for the fabrications of organic sensor devices based on the Au atomic layers.

  4. Anaerobic degradation of benzene by enriched consortia with humic acids as terminal electron acceptors

    Energy Technology Data Exchange (ETDEWEB)

    Cervantes, Francisco J., E-mail: fjcervantes@ipicyt.edu.mx [Division de Ciencias Ambientales, Instituto Potosino de Investigacion Cientifica y Tecnologica (IPICyT), Camino a la Presa San Jose 2055, Col. Lomas 4a. Seccion, San Luis Potosi, SLP, 78216 Mexico (Mexico); Mancilla, Ana Rosa; Toro, E. Emilia Rios-del [Division de Ciencias Ambientales, Instituto Potosino de Investigacion Cientifica y Tecnologica (IPICyT), Camino a la Presa San Jose 2055, Col. Lomas 4a. Seccion, San Luis Potosi, SLP, 78216 Mexico (Mexico); Alpuche-Solis, Angel G.; Montoya-Lorenzana, Lilia [Division de Biologia Molecular, Instituto Potosino de Investigacion Cientifica y Tecnologica (IPICyT), Camino a la Presa San Jose 2055, Col. Lomas 4a. Seccion, San Luis Potosi, SLP, 78216 Mexico (Mexico)

    2011-11-15

    Highlights: {yields} Enriched consortia were able to couple the anaerobic degradation of benzene to the reduction of humic acids. {yields} Electron-equivalents derived from anaerobic benzene oxidation were highly recovered as reduced humic acids. {yields} Several species from classes {beta}-, {delta}- and {gamma}-Proteobacteria were enriched during the anaerobic degradation of benzene. - Abstract: The anaerobic degradation of benzene coupled to the reduction of humic acids (HA) was demonstrated in two enriched consortia. Both inocula were able to oxidize benzene under strict anaerobic conditions when the humic model compound, anthraquinone-2,6-disulfonate (AQDS), was supplied as terminal electron acceptor. An enrichment culture originated from a contaminated soil was also able to oxidize benzene linked to the reduction of highly purified soil humic acids (HPSHA). In HPSHA-amended cultures, 9.3 {mu}M of benzene were degraded, which corresponds to 279 {+-} 27 micro-electron equivalents ({mu}Eq) L{sup -1}, linked to the reduction of 619 {+-} 81 {mu}Eq L{sup -1} of HPSHA. Neither anaerobic benzene oxidation nor reduction of HPSHA occurred in sterilized controls. Anaerobic benzene oxidation did not occur in soil incubations lacking HPSHA. Furthermore, negligible reduction of HPSHA occurred in the absence of benzene. The enrichment culture derived from this soil was dominated by two {gamma}-Proteobacteria phylotypes. A benzene-degrading AQDS-reducing enrichment originated from a sediment sample showed the prevalence of different species from classes {beta}-, {delta}- and {gamma}-Proteobacteria. The present study provides clear quantitative demonstration of anaerobic degradation of benzene coupled to the reduction of HA.

  5. Anaerobic degradation of benzene by enriched consortia with humic acids as terminal electron acceptors

    International Nuclear Information System (INIS)

    Cervantes, Francisco J.; Mancilla, Ana Rosa; Toro, E. Emilia Rios-del; Alpuche-Solis, Angel G.; Montoya-Lorenzana, Lilia

    2011-01-01

    Highlights: → Enriched consortia were able to couple the anaerobic degradation of benzene to the reduction of humic acids. → Electron-equivalents derived from anaerobic benzene oxidation were highly recovered as reduced humic acids. → Several species from classes β-, δ- and γ-Proteobacteria were enriched during the anaerobic degradation of benzene. - Abstract: The anaerobic degradation of benzene coupled to the reduction of humic acids (HA) was demonstrated in two enriched consortia. Both inocula were able to oxidize benzene under strict anaerobic conditions when the humic model compound, anthraquinone-2,6-disulfonate (AQDS), was supplied as terminal electron acceptor. An enrichment culture originated from a contaminated soil was also able to oxidize benzene linked to the reduction of highly purified soil humic acids (HPSHA). In HPSHA-amended cultures, 9.3 μM of benzene were degraded, which corresponds to 279 ± 27 micro-electron equivalents (μEq) L -1 , linked to the reduction of 619 ± 81 μEq L -1 of HPSHA. Neither anaerobic benzene oxidation nor reduction of HPSHA occurred in sterilized controls. Anaerobic benzene oxidation did not occur in soil incubations lacking HPSHA. Furthermore, negligible reduction of HPSHA occurred in the absence of benzene. The enrichment culture derived from this soil was dominated by two γ-Proteobacteria phylotypes. A benzene-degrading AQDS-reducing enrichment originated from a sediment sample showed the prevalence of different species from classes β-, δ- and γ-Proteobacteria. The present study provides clear quantitative demonstration of anaerobic degradation of benzene coupled to the reduction of HA.

  6. Halogenated benzenes, effect on xenobiotic metabolism and the toxicity of other chemicals. [Insecticides, rats

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, G.P.

    1977-01-01

    The insecticide EPN and six halogenated benzenes were administered orally to rats over a period of 14 days. The animals were killed 24 h after the last dose. Graphs are presented to show effects of halogenated benzene on EPN detoxification; liver to body weight ratio; and activities of benzpyrene hydroxylase, azoreductase, UDP glucuronyltransferase, and microsomal cytochrome c reductase. A significant enlargement of the liver was found. The results showed that the halogenated benzenes were capable of altering xenobiotic metabolism. (HLW)

  7. Determination of benzene in different food matrices by distillation and isotope dilution HS-GC/MS

    International Nuclear Information System (INIS)

    Medeiros Vinci, Raquel; Canfyn, Michael; De Meulenaer, Bruno; Schaetzen, Thibault de; Van Overmeire, Ilse; De Beer, Jacques; Van Loco, Joris

    2010-01-01

    Benzene is classified by the IARC as carcinogenic to humans. Several sources may contribute for the occurrence of benzene in foods, such as, environmental contamination and the reaction of benzoate salts with ascorbic acid (naturally present or added as food additives). Matrix effect on benzene recovery (e.g. in fatty foods) and artefactual benzene formation from benzoate during analysis in the presence of ascorbate are some of the challenges presented when determining benzene in a wide range of foodstuffs. Design of experiment (DOE) was used to determine the most important variables in benzene recovery from headspace GC/MS. Based on the results of the DOE, a versatile method for the extraction of benzene from all kind of food commodities was developed. The method which consisted of distillation and isotope dilution HS-GC/MS was in-house validated. Artefactual benzene was prevented by addition of a borate buffer solution (pH 11) under distillation conditions. The method presented in this study allows the use of a matrix-independent calibration with detection limits below the legal limit established by the European Council for benzene in drinking water (1 μg L -1 ).

  8. Human hemoglobin structural and functional alterations and heme degradation upon interaction with benzene: A spectroscopic study.

    Science.gov (United States)

    Hosseinzadeh, Reza; Moosavi-Movahedi, Ali Akbar

    2016-03-15

    Here, the effect of benzene on hemoglobin structure, stability and heme prosthetic group integrity was studied by different methods. These included UV-vis absorption spectrophotometry, normal and synchronous fluorescence techniques, and differential scanning calorimetry (DSC). Our results indicated that benzene has high hemolytic potential even at low concentrations. The UV-vis spectroscopic results demonstrated that benzene altered both the globin chain and the heme prosthetic group of hemoglobin increasing met- and deoxy-Hb, while decreasing oxy-Hb. However, with increasing benzene the concentration of all species decreased due to heme destruction. The spectrophotometric results show that benzene has a high potential for penetrating the hydrophobic pocket of hemoglobin. These results were consistent with the molecular docking simulation results of benzene-hHb. Aggregation and thermal denaturation studies show that the increased benzene concentration induced hemoglobin aggregation with a decrease in stability, which is consistent with the DSC results. Conventional fluorescence spectroscopy revealed that the heme degradation species were produced in the presence of benzene. The results of constant wavelength synchronous fluorescence spectroscopy (CWSFS) indicated that at least five heme-degraded species were produced. Together, our results indicated that benzene has adverse effects on hemoglobin structure and function, and heme degradation. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Assisted bioremediation tests on three natural soils contaminated with benzene

    Directory of Open Access Journals (Sweden)

    Maria Manuela Carvalho

    2015-07-01

    Full Text Available Bioremediation is an attractive and useful method of remediation of soils contaminated with petroleum hydrocarbons because it is simple to maintain, applicable in large areas, is economic and enables an effective destruction of the contaminant. Usually, the autochthone microorganisms have no ability to degrade these compounds, and otherwise, the contaminated sites have inappropriate environmental conditions for microorganism’s development. These problems can be overcome by assisted bioremediation (bioaugmentation and/or biostimulation. In this study the assisted bioremediation capacity on the rehabilitation of three natural sub-soils (granite, limestone and schist contaminated with benzene was evaluated. Two different types of assisted bioremediation were used: without and with ventilation (bioventing. The bioaugmentation was held by inoculating the soil with a consortium of microorganisms collected from the protection area of crude oil storage tanks in a refinery. In unventilated trials, biostimulation was accomplished by the addition of a nutrient mineral media, while in bioventing oxygen was also added. The tests were carried out at controlled temperature of 25 ºC in stainless steel columns where the moist soil contaminated with benzene (200 mg per kg of soil occupied about 40% of the column’s volume. The processes were daily monitored in discontinued mode. Benzene concentration in the gas phase was quantified by gas chromatography (GC-FID, oxygen and carbon dioxide concentrations were monitored by respirometry. The results revealed that the three contaminated soils were remediated using both technologies, nevertheless, the bioventing showed faster rates. With this work it was proved that respirometric analysis is an appropriate instrument for monitoring the biological activity.

  10. Exposition by inhalation to the benzene, toluene, ethyl-benzene and xylenes (BTEX) in the air. Sources, measures and concentrations; Exposition par inhalation au benzene, toluene, ethylbenzene et xylenes (BTEX) dans l'air. Source, mesures et concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Del Gratta, F.; Durif, M.; Fagault, Y.; Zdanevitch, I

    2004-12-15

    This document presents the main techniques today available to characterize the benzene, toluene, ethyl-benzene and xylene (BTEX) concentrations in the air for different contexts: urban and rural areas or around industrial installations but also indoor and occupational area. It provides information to guide laboratories and research departments. A synthesis gives also the main emissions sources of these compounds as reference concentrations measured in different environments. (A.L.B.)

  11. trans-Dichloridobis(triphenylphosphane-κPpalladium(II benzene hemisolvate

    Directory of Open Access Journals (Sweden)

    Frank Meyer-Wegner

    2012-04-01

    Full Text Available The title complex, [PdCl2(C18H15P2]·0.5C6H6, has the PdII ion in a square-planar coordination mode (r.m.s. deviation for Pd, P and Cl atoms = 0.024 Å with the PPh3 and Cl ligands mutually trans. The benzene solvent molecule is located about a crystallographic inversion centre. The title complex is isostructural with trans-dichloridobis(triphenylphosphanepalladium(II 1,4-dichlorobenzene sesquisolvate [Kitano et al. (1983. Acta Cryst. C39, 1015–1017].

  12. Subpicosecond pulse radiolysis in liquid methyl-substituted benzene derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Okamoto, Kazumasa [Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan)]. E-mail: kazu62@sanken.osaka-u.ac.jp; Kozawa, Takahiro [Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Saeki, Akinori [Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Yoshida, Yoichi [Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan); Tagawa, Seiichi [Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan)]. E-mail: tagawa@sanken.osaka-u.ac.jp

    2007-05-15

    The early processes of radiation chemistry in the picosecond time region in methyl-substituted benzene derivatives have been investigated using subpicosecond pulse radiolysis. In o-xylene, a fairly slow geminate ion recombination was observed within 50 ps after the electron beam irradiation; this is due to the smaller electron mobility. The kinetic traces were analyzed using the Smoluchowski equation with exponential and modified-Gaussian (YGP) functions as the distribution of thermalized electrons. Only exponential functions well reproduced the experimental data within 50 ps after the electron pulse.

  13. Bis[diethyl(hydroxyammonium] benzene-1,4-dicarboxylate

    Directory of Open Access Journals (Sweden)

    De-Ming Xie

    2010-08-01

    Full Text Available In the centrosymmetric title compound, 2C4H12NO+·C8H4O42−, two N,N-diethyl(hydroxyammonium cations are linked to a benzene-1,4-dicarboxylate dianion by a combination of O—H...O and N—H...O hydrogen bonds, which can be described in graph-set terminology as R22(7. The crystal structure is further stabilized by C—H...O hydrogen bonds, leading to the fomation of a ribbon-like network.

  14. The (p, ρ, T) of (methanol + benzene) and (methanol + ethylbenzene)

    International Nuclear Information System (INIS)

    Naziev, Yashar M.; Shahverdiyev, Astan N.; Hasanov, Vaqif H.

    2005-01-01

    The (p, ρ, T) of methanol, ethylbenzene and (methanol + benzene) and (methanol + ethylbenzene) at temperatures between (290 and 500) K and pressures in the range (0.1 to 60) MPa have been measured with a magnetic suspension densimeter with an uncertainty of ±0.1%. Our measurements with methanol deviate from the literature values by less than 0.2%. The (p, ρ, T) measurements were fitted with experimental uncertainties by an empirical equation. The temperature and mole fraction dependence of the coefficients of the equation of state are presented

  15. Subpicosecond pulse radiolysis in liquid methyl-substituted benzene derivatives

    International Nuclear Information System (INIS)

    Okamoto, Kazumasa; Kozawa, Takahiro; Saeki, Akinori; Yoshida, Yoichi; Tagawa, Seiichi

    2007-01-01

    The early processes of radiation chemistry in the picosecond time region in methyl-substituted benzene derivatives have been investigated using subpicosecond pulse radiolysis. In o-xylene, a fairly slow geminate ion recombination was observed within 50 ps after the electron beam irradiation; this is due to the smaller electron mobility. The kinetic traces were analyzed using the Smoluchowski equation with exponential and modified-Gaussian (YGP) functions as the distribution of thermalized electrons. Only exponential functions well reproduced the experimental data within 50 ps after the electron pulse

  16. Direct Hydroxylation of Benzene to Phenol over TS-1 Catalysts

    Directory of Open Access Journals (Sweden)

    Yuecheng Luo

    2018-01-01

    Full Text Available We synthesized a TS-1 catalyst to directly hydroxylate benzene to phenol with H2O2 as oxidant and water as solvent. The samples were characterized by FT-IR (Fourier Transform Infrared, DR UV-Vis (Diffused Reflectance Ultraviolet Visible, XRD (X-ray diffraction, SEM(scanning electron microscope, TEM (Transmission Electron Microscope, XPS (X-ray photoelectron spectroscopy, ICP (inductively coupled plasma spectrum, and N2 adsorption-desorption. A desirable phenol yield of 39% with 72% selectivity was obtained under optimized conditions: 0.15 g (0.34 to the mass of benzene TS-1, 5.6 mmol C6H6, reaction time 45 min, 0.80 mL H2O2 (30%, 40.0 mL H2O, and reaction temperature 70 °C. The reuse of the TS-1 catalyst illustrated that the catalyst had a slight loss of activity resulting from slight Ti leaching from the first run and then kept stable. Almost all of the Ti species added in the preparation were successfully incorporated into the TS-1 framework, which were responsible for the good catalytic activity. Extraframework Ti species were not selective for hydroxylation.

  17. Bis(2-formylphenyl benzene-1,2-dicarboxylate

    Directory of Open Access Journals (Sweden)

    Shaaban K. Mohamed

    2018-02-01

    Full Text Available The asymmetric unit of the title compound, C22H14O6, consists of two independent molecules differing in the orientations of the ester groups. In one molecule, the two terminal benzene rings are inclined to the central benzene ring by 4.99 (13 and 77.46 (13°, while in the other the corresponding angles are 11.03 (13 and 88.09 (12°. In the crystal, molecules are connected into a ribbon structure running along [101] via C—H...O and C—H...π interactions. Adjacent ribbons are further linked by additional C—H...O and C—H...π interactions. The crystal studied was a non-merohedral twin [twin law (0.986 − 0.073 − 0.008, 0.323 1.036 0.148, −0.121 − 0.102 0.942], the ratio of components being 0.937 (4:0.063 (4.

  18. Chemical accuracy from quantum Monte Carlo for the benzene dimer

    Energy Technology Data Exchange (ETDEWEB)

    Azadi, Sam, E-mail: s.azadi@ucl.ac.uk [Department of Earth Science and Thomas Young Centre, University College London, London WC1E 6BT (United Kingdom); Cohen, R. E. [London Centre for Nanotechnology, University College London, London WC1E 6BT, United Kingdom and Extreme Materials Initiative, Geophysical Laboratory, Carnegie Institution of Washington, Washington, D.C. 20015 (United States)

    2015-09-14

    We report an accurate study of interactions between benzene molecules using variational quantum Monte Carlo (VMC) and diffusion quantum Monte Carlo (DMC) methods. We compare these results with density functional theory using different van der Waals functionals. In our quantum Monte Carlo (QMC) calculations, we use accurate correlated trial wave functions including three-body Jastrow factors and backflow transformations. We consider two benzene molecules in the parallel displaced geometry, and find that by highly optimizing the wave function and introducing more dynamical correlation into the wave function, we compute the weak chemical binding energy between aromatic rings accurately. We find optimal VMC and DMC binding energies of −2.3(4) and −2.7(3) kcal/mol, respectively. The best estimate of the coupled-cluster theory through perturbative triplets/complete basis set limit is −2.65(2) kcal/mol [Miliordos et al., J. Phys. Chem. A 118, 7568 (2014)]. Our results indicate that QMC methods give chemical accuracy for weakly bound van der Waals molecular interactions, comparable to results from the best quantum chemistry methods.

  19. Catalytic oxidation of benzene using DBD corona discharges

    International Nuclear Information System (INIS)

    Lu, B.; Zhang, X.; Yu, X.; Feng, T.; Yao, S.

    2006-01-01

    Plasma oxidation of benzene (C 6 H 6 ) in oxygen and nitrogen was investigated using a dielectric barrier discharge (DBD) reactor with or without MnO 2 or TiO 2 at atmospheric pressure and without external heating except plasma heating. An alternative current power supply was used to generate corona discharges for the plasma oxidation. The energy density was controlled under 200 J/L to keep an increase in gas temperature less than 167 K. C 6 H 6 was oxidized to carbon monoxide (CO) and dioxide (CO 2 ). Typically, the energy efficiency at an energy density of 92 J/L was about 0.052, 0.039, and 0.024 mol/kWh with MnO 2 , TiO 2 , and without MnO 2 and TiO 2 , respectively. Benzene oxidation mechanism was mentioned. A comparison on energy efficiency as a function of initial concentration of hydrocarbons, inorganic sulphur compounds, and chloro (fluoro and bromo) carbons was given

  20. Biomonitoring of human population exposed to petroleum fuels with special consideration of the role of benzene as a genotoxic component. Report of the EC Environment programme. Project EV5V-CT

    Energy Technology Data Exchange (ETDEWEB)

    Carere, A.; Crebelli, R. [ed.] [Istituto Superiore di Sanita`, Rome (Italy). Lab. di Tossicologia Comparata ed Ecotossicologia

    1997-12-01

    In the framework of an EC research programme on the health risks of environmental chemicals, the Istituto Superiore di Sanita` co-ordinated, in 1993-1996, a project on the biological effects of benzene and petroleum fuels. Seven laboratories from six European countries collaborated in the biological monitoring of selected population with occupational exposure to petrochemicals. Several markers of early biological effect were applied together with environmental and personal exposure monitoring techniques. An epidemiological retrospective mortality study was also carried out on Italian filling station attendants. The results obtained highlighted an excess of genetic damage in some of the study populations, compared to matched unexposed controls. Even though these results do not allow a reliable risk estimation, the possible prognostic significance of cytogenetic damage for future cancer onset, together with some alerting findings from the mortality study, suggest that low dose exposures to benzene and petroleum fuels may retain some toxicological significance.

  1. [Study on repair capacity of DNA damage associated with chronic benzene poisoning].

    Science.gov (United States)

    Xing, Cai-hong; Ji, Zhi-ying; Li, Gui-lan; Yin, Song-nian

    2006-07-01

    To explore the repair capacity of DNA damage associated with chronic benzene poisonings. 63 workers suffered from chronic benzene poisonings and 45 workers exposed to benzene, who were engaged in the same job title, were investigated. Comet assay and cytokinesis-block micronucleus (CBMN) detection were used to evaluate gamma-radiation-induced DNA and chromosomal damage and repair capacity in peripheral blood lymphocyte. The comet tail length difference of the benzene poisoning group (4.64 +/- 1.57 microm) was significantly higher than that of the control group (3.77 +/- 1.30 microm) (P = 0.0029). There was no significant difference of the 3AB index between the poisoning group and the control group. The relative risk of benzene poisoning in the subject with comet tail length difference > 3.81 was significantly higher than that in the subject with comet tail length difference poisoning in the subject with 3AB index or = 0.20. DNA repair capacity on DNA-strand level might tightly associate with chronic benzene poisoning. The DNA repair capacity on DNA-strand level would be worse, and the benzene poisoning risk could be higher. There was no clear relation between the DNA repair capacity on chromosome level and the benzene poisoning risk.

  2. 40 CFR 80.1238 - How is a refinery's or importer's average benzene concentration determined?

    Science.gov (United States)

    2010-07-01

    ... concentration determined? (a) The average benzene concentration of gasoline produced at a refinery or imported... percent benzene). i = Individual batch of gasoline produced at the refinery or imported during the applicable averaging period. n = Total number of batches of gasoline produced at the refinery or imported...

  3. 40 CFR 80.1285 - How does a refiner apply for a benzene baseline?

    Science.gov (United States)

    2010-07-01

    ...) The benzene baseline for gasoline produced in 2004-2005 at the refinery, calculated in accordance with... PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Benzene Averaging, Banking and Trading... conventional gasoline. (4) A letter signed by the president, chief operating officer, or chief executive...

  4. 40 CFR 80.1280 - How are refinery benzene baselines calculated?

    Science.gov (United States)

    2010-07-01

    ... benzene). i = Individual batch of gasoline produced at the refinery from January 1, 2004 through December 31, 2005. n = Total number of batches of gasoline produced at the refinery from January 1, 2004... PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Benzene Averaging, Banking and Trading...

  5. Benzene degradation in a denitrifying biofilm reactor : activity and microbial community composition

    NARCIS (Netherlands)

    van der Waals, Marcelle J.; Atashgahi, Siavash; da Rocha, Ulisses Nunes; van der Zaan, Bas M.; Smidt, Hauke; Gerritse, Jan

    2017-01-01

    Benzene is an aromatic compound and harmful for the environment. Biodegradation of benzene can reduce the toxicological risk after accidental or controlled release of this chemical in the environment. In this study, we further characterized an anaerobic continuous biofilm culture grown for more than

  6. Reactions of osmabenzene with silver/copper acetylides: from metallabenzene to benzene.

    Science.gov (United States)

    Han, Feifei; Li, Jinhua; Zhang, Hong; Wang, Tongdao; Lin, Zhenyang; Xia, Haiping

    2015-01-07

    The transformations of metallabenzene to substituted benzenes have been achieved by reactions of osmabenzenes with silver/copper acetylides. In this investigation, novel tetraphenylphosphonium salts containing two phosphonium substituents on the same benzene ring are generated. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Benzene emission from the actual car fleet in relation to petrol composition in Denmark

    International Nuclear Information System (INIS)

    Palmgren, F.; Hansen, A.B.; Berkowicz, R.; Skov, H.

    2001-01-01

    The present study covers an investigation of the trends in air pollution levels of benzene in Danish cities and their relationship with the benzene content in petrol. Petrol samples from the two refineries in Denmark as well as sold petrol from some representative Danish petrol stations were analysed. The benzene content in Danish petrol was reduced from 3.5% for 95 octane prior to 1995 to approx. 2% in 1995 and further to 1% in 1998. Air quality measurements of aromatic VOC are available from two Danish cities; Copenhagen since 1994 and Odense since 1997. Measurements of benzene, CO and NO x from these two locations were analysed using the Operational Street Pollution Model (OSPM) and trends in the actual emissions of these pollutants were determined. It is shown that the decrease in both the concentration levels and in the emissions was significantly larger for benzene than for CO and NO x . The decreasing trends of NO x and CO could be explained by the increasing fraction of petrol-fuelled vehicles with three way catalysts (TWC). The much steeper decreasing trend for benzene can most likely be attributed to a combination of the effect of the increasing share of the TWC vehicles and a simultaneous reduction of benzene content in Danish petrol. The reduction of benzene concentrations and emissions is observed despite that the total amount of aromatics in petrol has increased slightly in the same period. (Author)

  8. Effect of Filler Loading on the Molecular Movement of Benzene and ...

    African Journals Online (AJOL)

    The sorption behaviour of the solvents – benzene and toluene in calcite-filled low density polyethylene composite samples at 40oC and 65oC were investigated using gravimetric sorption method. The effect of calcite loading on the molecular movement of benzene and toluene through the calcite-filled LDPE composites ...

  9. 40 CFR 80.1290 - How are standard benzene credits generated?

    Science.gov (United States)

    2010-07-01

    ... PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Benzene Averaging, Banking and Trading... approved under § 80.1340. (b) [Reserved] (c)(1) The number of standard benzene credits generated shall be... the nearest gallon. Fractional values shall be rounded down if less than 0.50, and rounded up if...

  10. Homolytic iodination and nitration of some benzene derivatives in the gas phase

    International Nuclear Information System (INIS)

    Vonk, W.F.M.

    1980-01-01

    Two gas phase reactions, involving the iodination and nitration of benzene derivatives, are described. The experimental techniques of the apparatus and the methods used are outlined. The kinetic H/D isotope effect in the gas phase nitration of benzene with NO 2 is determined. (C.F.)

  11. Product formation from thiophene by a mixed bacterial culture. Influence of benzene as growth substrate

    DEFF Research Database (Denmark)

    Rivas, Isabelle Marie; Mosbæk, Hans; Arvin, Erik

    2003-01-01

    The influence of benzene as a growth substrate on the cometabolic conversion of thiophene was investigated in batch systems with microorganisms originating from an creosote contaminated site. Benzene was shown to stimulate the conversion of thiophene with a first-order rate, during the initial...

  12. 40 CFR 80.55 - Measurement methods for benzene and 1,3-butadiene.

    Science.gov (United States)

    2010-07-01

    ... accomplished by bag sampling as used for total hydrocarbons determination. This procedure is detailed in 40 CFR 86.109. (b) Benzene and 1,3-butadiene must be analyzed by gas chromatography. Expected values for benzene and 1,3-butadiene in bag samples for the baseline fuel are 4.0 ppm and 0.30 ppm respectively. At...

  13. Differential susceptibility of rats and guinea pigs to the ototoxic effects of ethyl benzene

    NARCIS (Netherlands)

    Cappaert, N.L.M.; Klis, S.F.L.; Muijser, H.; Kulig, B.M.; Ravensberg, L.C.; Smoorenburg, G.F.

    2002-01-01

    The present study was designed to compare the ototoxic effects of volatile ethyl benzene in guinea pigs and rats. Rats showed deteriorated auditory thresholds in the mid-frequency range, based on electrocochleography, after 550-ppm ethyl benzene (8 h/day, 5 days). Outer hair cell (OHC) loss was

  14. Antioxidant Compounds in Traditional Indian Pickles May Prevent the Process-Induced Formation of Benzene.

    Science.gov (United States)

    Kharat, Mahesh M; Adiani, Vanshika; Variyar, Prasad; Sharma, Arun; Singhal, Rekha S

    2016-01-01

    Pickles in the Indian market contain ascorbic acid from the raw material used and benzoate as an added preservative that are involved in the formation of benzene in soft drinks. In this work, 24 market pickle samples were surveyed for benzene content, as well as its precursors and other constituents that influence its formation. The analysis showed that pickle samples were high in acid content (low pH) and showed significant amount of ascorbic acid, minerals (Cu and Fe), and benzoic acid present in them. Also, most samples exhibited high antioxidant activity that might be attributed to the ingredients used, such as fruits and spices. The solid-phase microextraction headspace gas chromatography-mass spectrometry method was developed in-house for benzene analysis. Eleven of 24 samples had benzene, with the highest concentration of 4.36 ± 0.82 μg of benzene per kg of pickle for a lime pickle that was also reported to have highest benzoic acid and considerably less hydroxyl radical ((•)OH) scavenging activity. However, benzene levels for all 11 samples were considerably below the World Health Organization regulatory limit of 10 μg/kg for benzene in mineral water. Studies on model systems revealed that the high antioxidant activity of Indian pickles may have had a strong inhibitory effect on benzene formation.

  15. Sulfur tolerance of Pt/mordenites for benzene hydrogenation. Do Bronsted acid sites participate in hydrogenation?

    NARCIS (Netherlands)

    Simon, L.; van Ommen, J.G.; Jentys, A.; Lercher, J.A.

    2002-01-01

    The comparison of Pt electronic properties studied by in situ XANES and the kinetic study of benzene hydrogenation strongly suggests that the hydrogenation of benzene on Pt/mordenites occurs along two parallel reaction pathways. The routes proposed include (i) the monofunctional hydrogenation of

  16. The role of CH $\\ldots $ interaction in the stabilization of benzene ...

    Indian Academy of Sciences (India)

    type of interaction between C-H groups of adamantane and cloud of benzene is found as the important attraction for complex formation. The study also reveals that the methylene (-CH2) and methine (-CH) groups of adamantane interact with benzene resulting in different geometrical structures. And it is found that the ...

  17. FORMATION OF HEMOGLOBIN AND ALBUMIN ADDUCTS OF BENZENE OXIDE IN MOUSE, RAT, AND HUMAN BLOOD

    Science.gov (United States)

    Little is known about the formation and disposition of benzene oxide (BO), the initial metabolite arising from oxidation of benzene by cytochrome P450. In this study, reactions of BO with hemoglobin (Hb) and albumin (Alb) were investigated in blood from B6C3F1 mice, F344 rats, ...

  18. Modeling benzene permeation through drinking water high density polyethylene (HDPE) pipes.

    Science.gov (United States)

    Mao, Feng; Ong, Say Kee; Gaunt, James A

    2015-09-01

    Organic compounds such as benzene, toluene, ethyl benzene and o-, m-, and p-xylene from contaminated soil and groundwater may permeate through thermoplastic pipes which are used for the conveyance of drinking water in water distribution systems. In this study, permeation parameters of benzene in 25 mm (1 inch) standard inside dimension ratio (SIDR) 9 high density polyethylene (HDPE) pipes were estimated by fitting the measured data to a permeation model based on a combination of equilibrium partitioning and Fick's diffusion. For bulk concentrations between 6.0 and 67.5 mg/L in soil pore water, the concentration-dependent diffusion coefficients of benzene were found to range from 2.0×10(-9) to 2.8×10(-9) cm2/s while the solubility coefficient was determined to be 23.7. The simulated permeation curves of benzene for SIDR 9 and SIDR 7 series of HDPE pipes indicated that small diameter pipes were more vulnerable to permeation of benzene than large diameter pipes, and the breakthrough of benzene into the HDPE pipe was retarded and the corresponding permeation flux decreased with an increase of the pipe thickness. HDPE pipes exposed to an instantaneous plume exhibited distinguishable permeation characteristics from those exposed to a continuous source with a constant input. The properties of aquifer such as dispersion coefficients (DL) also influenced the permeation behavior of benzene through HDPE pipes.

  19. Healthy people and healthy profits? Elaborating a conceptual framework for governing the commercial determinants of non-communicable diseases and identifying options for reducing risk exposure.

    Science.gov (United States)

    Buse, Kent; Tanaka, Sonja; Hawkes, Sarah

    2017-06-15

    Non-communicable diseases (NCDs) represent a significant threat to human health and well-being, and carry significant implications for economic development and health care and other costs for governments and business, families and individuals. Risks for many of the major NCDs are associated with the production, marketing and consumption of commercially produced food and drink, particularly those containing sugar, salt and transfats (in ultra-processed products), alcohol and tobacco. The problems inherent in primary prevention of NCDs have received relatively little attention from international organizations, national governments and civil society, especially when compared to the attention paid to secondary and tertiary prevention regimes (i.e. those focused on provision of medical treatment and long-term clinical management). This may in part reflect that until recently the NCDs have not been deemed a priority on the overall global health agenda. Low political priority may also be due in part to the complexity inherent in implementing feasible and acceptable interventions, such as increased taxation or regulation of access, particularly given the need to coordinate action beyond the health sector. More fundamentally, governing determinants of risk frequently brings public health into conflict with the interests of profit-driven food, beverage, alcohol and tobacco industries. We use a conceptual framework to review three models of governance of NCD risk: self-regulation by industry; hybrid models of public-private engagement; and public sector regulation. We analyse the challenges inherent in each model, and review what is known (or not) about their impact on NCD outcomes. While piecemeal efforts have been established, we argue that mechanisms to control the commercial determinants of NCDs are inadequate and efforts at remedial action too limited. Our paper sets out an agenda to strengthen each of the three governance models. We identify reforms that will be needed

  20. Methane, benzene and alkyl benzene cold start emission data of gasoline-driven passenger cars representing the vehicle technology of the last two decades

    Science.gov (United States)

    Heeb, Norbert V.; Forss, Anna-Maria; Saxer, Christian J.; Wilhelm, Patrick

    The US urban driving cycle (FTP-75) is widely used to estimate both the emissions under hot engine conditions as well as those associated with the cold start. Applying fast analysis techniques such as chemical ionization mass spectrometry (CI-MS) the warm-up behavior of individual vehicles can be monitored at a time resolution of 1 s. CI-MS has been used to investigate the emissions of methane, benzene and the alkyl benzene class of compounds. The amount of the emissions at cold start influence was deduced from the time-resolved emission data of four gasoline-driven vehicle classes representing the vehicle technology of the last two decades. Overall, the emissions of five EURO-0, 20 EURO-1, 18 EURO-2 and so far of six EURO-3 passenger cars were recorded. The test vehicles were selected from the currently operating Swiss car fleet based on the car sales statistics. The average methane, benzene and alkyl benzene cold start emissions are reported using both, the traditional bag method as well as the regression model. At room temperature a clear reduction of 94%, 81% and 85% was found for the methane, benzene and alkyl benzene cold start emissions from EURO-0 to EURO-3 technology, respectively.

  1. Benzene-poly-carboxylic acid complex, a novel anti-cancer agent induces apoptosis in human breast cancer cells.

    Directory of Open Access Journals (Sweden)

    Fuad Fares

    Full Text Available Some cases of breast cancer are composed of clones of hormonal-independent growing cells, which do not respond to therapy. In the present study, the effect of Benzene-Poly-Carboxylic Acid Complex (BP-C1 on growth of human breast-cancer cells was tested. BP-C1 is a novel anti-cancer complex of benzene-poly-carboxylic acids with a very low concentration of cis-diammineplatinum (II dichloride. Human breast cancer cells, MCF-7 and T47D, were used. Cell viability was detected by XTT assay and apoptosis was detected by Flow Cytometry and by annexin V/FITC/PI assay. Caspases were detected by western blot analysis and gene expression was measured by using the Applied Biosystems® TaqMan® Array Plates. The results showed that exposure of the cells to BP-C1 for 48 h, significantly (P<0.001 reduced cell viability, induced apoptosis and activated caspase 8 and caspace 9. Moreover, gene expression experiments indicated that BP-C1 increased the expression of pro-apoptotic genes (CASP8AP1, TNFRSF21, NFkB2, FADD, BCL10 and CASP8 and lowered the level of mRNA transcripts of inhibitory apoptotic genes (BCL2L11, BCL2L2 and XIAP. These findings may lead to the development of new therapeutic strategies for treatment of human cancer using BP-C1 analog.

  2. A chromosomally based tod-luxCDABE whole-cell reporter for benzene, toluene, ethybenzene, and xylene (BTEX) sensing

    International Nuclear Information System (INIS)

    Applegate, B.M.; Kehrmeyer, S.R.; Sayler, G.S.

    1998-01-01

    A tod-luxCDABE fusion was constructed and introduced into the chromosome of Pseudomonas putida F1, yielding the strain TVA8. This strain was used to examine the induction of the tod operon when exposed to benzene, toluene, ethylbenzene, and xylene (BTEX) compounds and aqueous solutions of JP-4 jet fuel constituents. Since this system contained the complete lux cassette (luxCDABE), bacterial bioluminescence in response to putative chemical inducers of the tod operon was measured on-line in whole cells without added aldehyde substrate. There was an increasing response to toluene concentrations from 30 microg/liter to 50 mg/liter, which began to saturate at higher concentrations. The detection limit was 30 microg/liter. There was a significant light response to benzene, m- and p-xylenes, phenol, and water-soluble JP-4 jet fuel components, but there was no bioluminescence response upon exposure to o-xylene. The transposon insertion was stable and had no negative effect on cell growth

  3. Effects of hydrogen and acetate on benzene mineralisation under sulphate-reducing conditions.

    Science.gov (United States)

    Rakoczy, Jana; Schleinitz, Kathleen M; Müller, Nicolai; Richnow, Hans H; Vogt, Carsten

    2011-08-01

    Syntrophic mineralisation of benzene, as recently proposed for a sulphate-reducing enrichment culture, was tested in product inhibition experiments with acetate and hydrogen, both putative intermediates of anaerobic benzene fermentation. Using [(13)C(6)]-benzene enabled tracking the inhibition of benzene mineralisation sensitively by analysis of (13)CO(2). In noninhibited cultures, hydrogen was detected at partial pressures of 2.4 × 10(-6) ± 1.5 × 10(-6) atm. Acetate was detected at concentrations of 17 ± 2 μM. Spiking with 0.1 atm hydrogen produced a transient inhibitory effect on (13)CO(2) formation. In cultures spiked with higher amounts of hydrogen, benzene mineralisation did not restart after hydrogen consumption, possibly due to the toxic effects of the sulphide produced. An inhibitory effect was also observed when acetate was added to the cultures (0.3, 3.5 and 30 mM). Benzene mineralisation resumed after acetate was degraded to concentrations found in noninhibited cultures, indicating that acetate is another key intermediate in anaerobic benzene mineralisation. Although benzene mineralisation by a single sulphate reducer cannot be ruled out, our results strongly point to an involvement of syntrophic interactions in the process. Thermodynamic calculations revealed that, under in situ conditions, benzene fermentation to hydrogen and acetate yielded a free energy change of ΔG'=-83.1 ± 5.6 kJ mol(-1). Benzene mineralisation ceased when ΔG' values declined below -61.3 ± 5.3 kJ mol(-1) in the presence of acetate, indicating that ATP-consuming reactions are involved in the pathway. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  4. Assessment of occupational exposure to BTEX compounds at a bus diesel-refueling bay: A case study in Johannesburg, South Africa.

    Science.gov (United States)

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

    2015-12-15

    Of increasing concern is pollution by volatile organic compounds, with particular reference to five aromatic hydrocarbons (benzene, toluene, ethyl benzene and two isomeric xylenes; BTEX). These pollutants are classified as hazardous air pollutants. Due to the potential health risks associated with these pollutants, BTEX concentrations were monitored at a bus diesel-refueling bay, in Johannesburg, South Africa, using gas chromatography, coupled with a photo-ionization detector. Results indicate that o-xylene (29-50%) and benzene (13-33%) were found to be the most abundant species of total BTEX at the site. Benzene was within South African occupational limits, but above international occupational exposure limits. On the other hand, occupational concentrations of toluene, ethyl-benzene and xylenes were within national and international occupational limits throughout the monitoring period, based on 8-hour workday weighted averages. Ethyl-benzene and p-xylene concentrations, during winter, correspond to activity at the site, and thus idling of buses during refueling may elevate results. Overall, occupational air quality at the refueling bay is a matter of health concern, especially with regards to benzene exposure, and future reduction strategies are crucial. Discrepancies between national and international limit values merit further investigation to determine whether South African guidelines for benzene are sufficiently precautionary. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Evaluation of seawater contamination with benzene, toluene and xylene in the Ubatuba north coast, SP region, and study of their removal by ionizing radiation

    International Nuclear Information System (INIS)

    Almeida, Kelly Cristina Santana de

    2006-01-01

    A major concern with leaking petroleum is the environmental contamination by the toxic and low water-soluble components such as benzene, toluene, and xylenes (BTX). These hydrocarbons have relatively high pollution potential because of their significant toxicity. The objective of this study was to evaluate the contamination of seawater by the main pollutants of the output and transport of petroleum, such as benzene, toluene, and xylene, and their removal by the exposure to the ionizing radiation. The studied region was Ubatuba region, SP, between 23 deg 26'S and 23 deg 46'S of latitude and 45 deg 02'W and 45 deg 11'W of longitude, area of carry and output of petroleum, and samples were collected from November, 2003 to July, 2005. For BTX in seawater analysis, the Purge and Trap concentrator with FIDGC detector showed significantly higher sensibility than Head Space concentrator with MSGC detector. The minimal detected limits (MDL) obtained at FIDGC were of 0.50 μg/L for benzene, 0.70 μg/L for toluene, and 1.54 μg/L for xylene, and the obtained experimental variability was 15%. While the concentrator type Headspace system with MS detector showed higher MLD, about of 9.30 mg/L for benzene, 8.50 mg/L for toluene, and 9.80 mg/L for xylene, and 10% of experimental variability. In the studied area the benzene concentration varied from 1.0 μg/L to 2.0 μg/L, the concentration of toluene varied from 60 Co, presented a removal from 10% to 40% of benzene at 20 kGy absorbed doses and concentration of 35.1 mg/L and 70.2 mg/L, respectively; from 20% to 60% of toluene removal with 15 kGy absorbed dose and from 20% to 80% of xylene with 15 kGy absorbed dose in similar concentrations. (author)

  6. 78 FR 13707 - The Benzene Standard; Extension of the Office of Management and Budget's (OMB) Approval of...

    Science.gov (United States)

    2013-02-28

    ... Occupational Safety and Health Administration The Benzene Standard; Extension of the Office of Management and... the information collection requirements specified in the Benzene Standard (29 CFR 1910.1028). DATES... obtaining information (29 U.S.C. 657). The information collection requirements specified in the Benzene...

  7. Indoor Exposure and Adverse Birth Outcomes Related to Fetal Growth, Miscarriage and Prematurity—A Systematic Review

    Directory of Open Access Journals (Sweden)

    Evridiki Patelarou

    2014-06-01

    Full Text Available The purpose of this review was to summarize existing epidemiological evidence of the association between quantitative estimates of indoor air pollution and all-day personal exposure with adverse birth outcomes including fetal growth, prematurity and miscarriage. We carried out a systematic literature search of MEDLINE and EMBASE databases with the aim of summarizing and evaluating the results of peer-reviewed epidemiological studies undertaken in “westernized” countries that have assessed indoor air pollution and all-day personal exposure with specific quantitative methods. This comprehensive literature search identified 16 independent studies which were deemed relevant for further review and two additional studies were added through searching the reference lists of all included studies. Two reviewers independently and critically appraised all eligible articles using the Critical Appraisal Skills Programme (CASP tool. Of the 18 selected studies, 14 adopted a prospective cohort design, three were case-controls and one was a retrospective cohort study. In terms of pollutants of interest, seven studies assessed exposure to electro-magnetic fields, four studies assessed exposure to polycyclic aromatic hydrocarbons, four studies assessed PM2.5 exposure and three studies assessed benzene, phthalates and noise exposure respectively. Furthermore, 12 studies examined infant growth as the main birth outcome of interest, six examined spontaneous abortion and three studies assessed gestational age at birth and preterm delivery. This survey demonstrates that there is insufficient research on the possible association of indoor exposure and early life effects and that further research is needed.

  8. Direct detection of benzene, toluene, and ethylbenzene at trace levels in ambient air by atmospheric pressure chemical ionization using a handheld mass spectrometer.

    Science.gov (United States)

    Huang, Guangming; Gao, Liang; Duncan, Jason; Harper, Jason D; Sanders, Nathaniel L; Ouyang, Zheng; Cooks, R Graham

    2010-01-01

    The capabilities of a portable mass spectrometer for real-time monitoring of trace levels of benzene, toluene, and ethylbenzene in air are illustrated. An atmospheric pressure interface was built to implement atmospheric pressure chemical ionization for direct analysis of gas-phase samples on a previously described miniature mass spectrometer (Gao et al. Anal. Chem.2006, 78, 5994-6002). Linear dynamic ranges, limits of detection and other analytical figures of merit were evaluated: for benzene, a limit of detection of 0.2 parts-per-billion was achieved for air samples without any sample preconcentration. The corresponding limits of detection for toluene and ethylbenzene were 0.5 parts-per-billion and 0.7 parts-per-billion, respectively. These detection limits are well below the compounds' permissible exposure levels, even in the presence of added complex mixtures of organics at levels exceeding the parts-per-million level. The linear dynamic ranges of benzene, toluene, and ethylbenzene are limited to approximately two orders of magnitude by saturation of the detection electronics. 2010 American Society for Mass Spectrometry. Published by Elsevier Inc. All rights reserved.

  9. Electronic Conductivity of Polypyrrole−Dodecyl Benzene Sulfonate Complexes

    DEFF Research Database (Denmark)

    West, Keld; Bay, Lasse; Nielsen, Martin Meedom

    2004-01-01

    and therefore smaller hopping distances. This was supported by X-ray measurements. Synthesis at lower temperatures generally leads to higher conductivity. The conductivity is strongly dependent on the potential, being more than four magnitudes smaller for the reduced state where the number of electronic......The electronic conductivity of the electroactive polymer polypyrrole-dodecyl benzene sulfonate (PPy-DBS) has been characterized as function of the redox level. The polymer was synthesized with different isomers of the dopant anions: the common mixed DBS tenside and three well-defined synthetic....... These investigations demonstrate that even minor differences in the dopant anion can cause significant changes in the physical properties of the electroactive polymer. The highest conductivities ($sigma$-25$/ = 39 Scm$+-1$/) are obtained by the (6D)BS isomer, perhaps because the branching leads to denser packing...

  10. Short-term exposure to high levels of air pollution as a risk factor for acute isolated pulmonary embolism.

    Science.gov (United States)

    Spiezia, Luca; Campello, Elena; Bon, Maria; Maggiolo, Sara; Pelizzaro, Elena; Simioni, Paolo

    2014-08-01

    The association between air pollution exposure and occurrence of venous thromboembolism is a matter of debate. This retrospective case-control study investigated the associations between one month's exposure to elevated levels of different pollutants (i.e. PM10, CO, NOx, O3, SO2, Benzene, Benzoapyrene, Nickel, Lead Arsenic) and the development of acute isolated pulmonary embolism (PE). The cases included 33 patients consecutively admitted to Padua Hospital with an objectively proven diagnosis of acute unprovoked (i.e. without predisposing conditions) isolated (i.e. without deep vein thrombosis) PE. The control group consisted of 72 consecutive patients with objectively proven acute provoked (i.e. associated to predisposing conditions) isolated PE. Average mean concentrations of pollutants in the month before PE diagnosis were computed by monitors located at 2 different sites throughout the city of Padua, and were obtained from the Regional Agency for Environmental Protection. Individuals who had PM10, NOx, Benzene, Benzoapyrene, Cadmium, and Lead exposure equal/above the 2nd tertile, measured in controls, showed a significant increase in the risk of unprovoked PE. In case of PM10 and Benzoapyrene this risk was not affected after adjustment for possible confounders. In fact, in the multivariate logistic regression analysis, the OR values were 5.24 (95% CI: 1.52-18.12) for PM10 and 3.95 (95% CI: 1.06-14.71) for Benzoapyrene exposure in the month before PE diagnosis. Our results, although preliminary, identify short-term (i.e. one month) exposure to elevate levels of air pollutants as a possible risk factor for the development of acute isolated PE. Larger studies are needed to confirm our results. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Hydrogeologic characterization and assessment of bioremediation of chlorinated benzenes and benzene in wetland areas, Standard Chlorine of Delaware, Inc. Superfund Site, New Castle County, Delaware, 2009-12

    Science.gov (United States)

    Lorah, Michelle M.; Walker, Charles W.; Baker, Anna C.; Teunis, Jessica A.; Majcher, Emily H.; Brayton, Michael J.; Raffensperger, Jeff P.; Cozzarelli, Isabelle M.

    2014-01-01

    Wetlands at the Standard Chlorine of Delaware, Inc. Superfund Site (SCD) in New Castle County, Delaware, are affected by contamination with chlorobenzenes and benzene from past waste storage and disposal, spills, leaks, and contaminated groundwater discharge. In cooperation with the U.S. Environmental Protection Agency, the U.S. Geological Survey began an investigation in June 2009 to characterize the hydrogeology and geochemistry in the wetlands and assess the feasibility of monitored natural attenuation and enhanced bioremediation as remedial strategies. Groundwater flow in the wetland study area is predominantly vertically upward in the wetland sediments and the underlying aquifer, and groundwater discharge accounts for a minimum of 47 percent of the total discharge for the subwatershed of tidal Red Lion Creek. Thus, groundwater transport of contaminants to surface water could be significant. The major contaminants detected in groundwater in the wetland study area included benzene, monochlorobenzene, and tri- and di-chlorobenzenes. Shallow wetland groundwater in the northwest part of the wetland study area was characterized by high concentrations of total chlorinated benzenes and benzene (maximum about 75,000 micrograms per liter [μg/L]), low pH, and high chloride. In the northeast part of the wetland study area, wetland groundwater had low to moderate concentrations of total chlorinated benzenes and benzene (generally not greater than 10,000 μg/L), moderate pH, and high sulfate concentrations. Concentrations in the groundwater in excess of 1 percent of the solubility of the individual chlorinated benzenes indicate that a contaminant source is present in the wetland sediments as dense nonaqueous phase liquids (DNAPLs). Consistently higher contaminant concentrations in the shallow wetland groundwater than deeper in the wetland sediments or the aquifer also indicate a continued source in the wetland sediments, which could include dissolution of DNAPLs and

  12. Benzene Uptake and Glutathione S-transferase T1 Status as Determinants of S-Phenylmercapturic Acid in Cigarette Smokers in the Multiethnic Cohort.

    Directory of Open Access Journals (Sweden)

    Christopher A Haiman

    Full Text Available Research from the Multiethnic Cohort (MEC demonstrated that, for the same quantity of cigarette smoking, African Americans and Native Hawaiians have a higher lung cancer risk than Whites, while Latinos and Japanese Americans are less susceptible. We collected urine samples from 2,239 cigarette smokers from five different ethnic groups in the MEC and analyzed each sample for S-phenylmercapturic acid (SPMA, a specific biomarker of benzene uptake. African Americans had significantly higher (geometric mean [SE] 3.69 [0.2], p<0.005 SPMA/ml urine than Whites (2.67 [0.13] while Japanese Americans had significantly lower levels than Whites (1.65 [0.07], p<0.005. SPMA levels in Native Hawaiians and Latinos were not significantly different from those of Whites. We also conducted a genome-wide association study in search of genetic risk factors related to benzene exposure. The glutathione S-transferase T1 (GSTT1 deletion explained between 14.2-31.6% (p = 5.4x10-157 and the GSTM1 deletion explained between 0.2%-2.4% of the variance (p = 1.1x10-9 of SPMA levels in these populations. Ethnic differences in levels of SPMA remained strong even after controlling for the effects of these two deletions. These results demonstrate the powerful effect of GSTT1 status on SPMA levels in urine and show that uptake of benzene in African American, White, and Japanese American cigarette smokers is consistent with their lung cancer risk in the MEC. While benzene is not generally considered a cause of lung cancer, its metabolite SPMA could be a biomarker for other volatile lung carcinogens in cigarette smoke.

  13. Monitoring benzene formation from benzoate in model systems by proton transfer reaction-mass spectrometry

    Science.gov (United States)

    Aprea, Eugenio; Biasioli, Franco; Carlin, Silvia; Märk, Tilmann D.; Gasperi, Flavia

    2008-08-01

    The presence of benzene in food and in particular in soft drinks has been reported in several studies and should be considered in fundamental investigations about formation of this carcinogen compound as well as in quality control. Proton transfer reaction-mass spectrometry (PTR-MS) has been used here for rapid, direct quantification of benzene and to monitor its formation in model systems related to the use of benzoate, a common preservative, in presence of ascorbic acid: a widespread situation that yields benzene in, e.g., soft drinks and fruit juices. Firstly, we demonstrate here that PTR-MS allows a rapid determination of benzene that is in quantitative agreement with independent solid phase micro-extraction/gas chromatography (SPME/GC) analysis. Secondly, as a case study, the effect of different sugars (sucrose, fructose and glucose) on benzene formation is investigated indicating that they inhibit its formation and that this effect is enhanced for reducing sugars. The sugar-induced inhibition of benzene formation depends on several parameters (type and concentration of sugar, temperature, time) but can be more than 80% in situations that can be expected in the storage of commercial soft drinks. This is consistent with the reported observations of higher benzene concentrations in sugar-free soft drinks.

  14. Denitrification synergized with ANAMMOX for the anaerobic degradation of benzene: performance and microbial community structure.

    Science.gov (United States)

    Peng, Shuchan; Zhang, Lilan; Zhang, DaiJun; Lu, Peili; Zhang, Xiaoting; He, Qiang

    2017-05-01

    To evaluate the effect of anaerobic ammonium oxidation (ANAMMOX) on benzene degradation under denitrification, a sequencing batch reactor (SBR) under denitrification synergized with ANAMMOX (SBR-DenAna) for benzene degradation was established by inoculating anaerobic ammonium-oxidizing bacteria (AnAOB) into a SBR under denitrification reactor (SBR-Den) for benzene degradation. The average rate of benzene degradation and the maximum first-order kinetic constant in SBR-DenAna were 2.34- and 1.41-fold those in SBR-Den, respectively, indicating that ANAMMOX improved the degradation of benzene under denitrification synergized with ANAMMOX. However, the average rate of benzene degradation decreased by 35% in the denitrification-ANAMMOX synergistic reactor when 10 mg N L -1 NO 2 - was added; the rate recovered once NO 2 - was depleted, indicating that ANAMMOX might detoxify NO 2 - . Results from high-throughput sequencing analysis revealed that Azoarcus within the family Rhodocyclaceae might be associated with benzene degradation in the two SBRs. AnAOB affiliated with the family Candidatus Brocadiaceae were just detected in SBR-DenAna.

  15. In vitro and in vivo metabolism of trans,trans-muconaldehyde, a hematotoxic microsomal metabolite of benzene

    Energy Technology Data Exchange (ETDEWEB)

    Kirley, T.A.

    1989-01-01

    Trans,trans-muconaldehyde (MUC) has been previously identified in the authors laboratory as a hematotoxic microsomal ring-opened metabolite of benzene. Trans,trans-muconic acid (MA), a known urinary metabolite of benzene, has been proposed to be a metabolite of MUC. The present studies were undertaken to determine (1) whether MUC is a precursor of urinary MA and (2) whether differences in oxidative metabolism of MUC might account for differences in benzene sensitivity among DBA and C57Bl mice. The in vivo metabolism of MUC was compared among DBA/2J and C57Bl/63 which have known differences in acetaldehyde metabolism. The present studies demonstrate that purified yeast aldehyde dehydrogenase (ALDH) in the presence of NAD{sup +} metabolizes MUC based on the production of NADH measured spectrophotometrically at 340 nm. In similar experiments, cytosol prepared from the liver of DBA/2J and C57Bl/6J mice and supplemented with NAD{sup +} was also found to metabolize MUC. Using TLC and HPLC techniques, a product with intermediate polarity compared with that of the dialdehyde (MUC) and the diacid trans,trans-muconic acid (MA) standards was detected in both the ALDH and mouse liver cytosol incubation mixtures. Mass spectral analysis and functional group tests support a structural assignment of OHC-CH{double bond}CH-CH{double bond}CH-COOH for this intermediate. This intermediate inhibited yeast ALDH. In the presence of liver cytosol supplemented with NAD{sup +} this intermediate was further metabolized to MA. This monoacid is a major metabolite of MUC in vitro. An alternate mechanism for the oxidative metabolism of MUC in may involve oxidases. In the presence of ruptured mouse liver mitochondria or purified milk xanthine oxidase, MUC is metabolized to the monocarboxylic acid-aldehyde and MA as determined by HPLC.

  16. The Use of Online Posts to Identify Barriers to and Facilitators of HIV Pre-exposure Prophylaxis (PrEP) Among Men Who Have Sex with Men: A Comparison to a Systematic Review of the Peer-Reviewed Literature.

    Science.gov (United States)

    Hannaford, Alisse; Lipshie-Williams, Madeleine; Starrels, Joanna L; Arnsten, Julia H; Rizzuto, Jessica; Cohen, Phillip; Jacobs, Damon; Patel, Viraj V

    2018-04-01

    Pre-exposure prophylaxis (PrEP) remains an under-utilized HIV prevention tool among men who have sex with men (MSM). To more comprehensively elucidate barriers and facilitators to PrEP use among US MSM, we conducted a systematic review of peer-reviewed published articles and content analysis of online posts about PrEP. We searched peer-reviewed databases (Medline, Web of Science, Google Scholar) using MESH headings and keywords about PrEP and/or HIV prevention from 2005 to 2015. We included original studies among MSM in the US that reported on barriers, facilitators, or other factors related to PrEP use. We also searched online posts and associated comments (news articles, opinion pieces, blogs and other social media posts) in diverse venues (Facebook, Slate Outward, Huffington Post Gay Voices, Queerty, and My PrEP Experience blog) to identify posts about PrEP. We used content analysis to identify themes and compare potential differences between the peer-reviewed literature and online posts. We identified 25 peer-reviewed articles and 28 online posts meeting inclusion criteria. We identified 48 unique barriers and 46 facilitators to using PrEP. These 94 themes fit into six overarching categories: (1) access (n = 14), (2) attitudes/beliefs (n = 24), (3) attributes of PrEP (n = 13), (4) behaviors (n = 11), (5) sociodemographic characteristics (n = 8), and (6) social network (n = 6). In all categories, analysis of online posts resulted in identification of a greater number of unique themes. Thirty-eight themes were identified in the online posts that were not identified in the peer-reviewed literature. We identified barriers and facilitators to PrEP in online posts that were not identified in a systematic review of the peer-reviewed literature. By incorporating data both from a systematic review of peer-reviewed articles and from online posts, we have identified salient and novel information about barriers to and facilitators of PrEP use. Traditional

  17. [Studies of ozone formation potentials for benzene and ethylbenzene using a smog chamber and model simulation].

    Science.gov (United States)

    Jia, Long; Xu, Yong-Fu

    2014-02-01

    Ozone formation potentials from irradiations of benzene-NO(x) and ethylbenzene-NO(x) systems under the conditions of different VOC/NO(x) ratios and RH were investigated using a characterized chamber and model simulation. The repeatability of the smog chamber experiment shows that for two sets of ethylbenzene-NO(x) irradiations with similar initial concentrations and reaction conditions, such as temperature, relative humidity and relative light intensity, the largest difference in O3 between two experiments is only 4% during the whole experimental run. On the basis of smog chamber experiments, ozone formation of photo-oxidation of benzene and ethylbenzene was simulated in terms of the master chemical mechanism (MCM). The peak ozone values for benzene and ethylbenzene simulated by MCM are higher than the chamber data, and the difference between the MCM-simulated results and chamber data increases with increasing RH. Under the conditions of sunlight irradiations, with benzene and ethylbenzene concentrations being in the range of (10-50) x 10(-9) and NO(x) concentrations in the range of (10-100) x 10(-9), the 6 h ozone contributions of benzene and ethylbenzene were obtained to be (3.1-33) x 10(-9) and (2.6-122) x 10(-9), whereas the peak O3 contributions of benzene and ethylbenzene were (3.5-54) x 10(-9) and (3.8-164) x 10(-9), respectively. The MCM-simulated maximum incremental reactivity (MIR) values for benzene and ethylbenzene were 0.25/C and 0.97/C (per carbon), respectively. The maximum ozone reactivity (MOR) values for these two species were obtained to be 0.73/C and 1.03/C, respectively. The MOR value of benzene from MCM is much higher than that obtained by carter from SAPRC, indicating that SAPRC may underestimate the ozone formation potential of benzene.

  18. Spin Polarization Inversion at Benzene-Absorbed Fe4N Surface

    KAUST Repository

    Zhang, Qian

    2015-05-27

    We report a first-principle study on electronic structure and simulation of the spin-polarized scanning tunneling microscopy graphic of a benzene/Fe4N interface. Fe4N is a compound ferromagnet suitable for many spintronic applications. We found that, depending on the particular termination schemes and interface configurations, the spin polarization on the benzene surface shows a rich variety of properties ranging from cosine-type oscillation to polarization inversion. Spin-polarization inversion above benzene is resulting from the hybridizations between C pz and the out-of-plane d orbitals of Fe atom.

  19. Separation of benzene from mixtures with water, methanol, ethanol, and acetone: highlighting hydrogen bonding and molecular clustering influences in CuBTC

    NARCIS (Netherlands)

    Gutiérrez-Sevillano, J.J.; Calero, S.; Krishna, R.

    2015-01-01

    Configurational-bias Monte Carlo (CBMC) simulations are used to establish the potential of CuBTC for separation of water/benzene, methanol/benzene, ethanol/benzene, and acetone/benzene mixtures. For operations under pore saturation conditions, the separations are in favor of molecules that partner

  20. Benzene and MTBE Sorption in Fine Grain Sediments

    Science.gov (United States)

    Leal-Bautista, R. M.; Lenczewski, M. E.

    2003-12-01

    The practice of adding methyl tert-butyl ether (MTBE) to gasoline started in the late 1970s and increased dramatically in the 1990s. MTBE first was added as a substitute for tetra-ethyl lead then later as a fuel oxygenate. Although the use of MTBE has resulted in significant reduction in air pollution, it has become a significant groundwater contaminant due to its high solubility in water, high environmental mobility, and low potential for biodegradation. A recent report (1999-2001) by the Metropolitan Water District of Southern California in collaboration with United State Geological Survey and the Oregon Health and Science University found that MTBE was the second most frequent detected volatile organic compound in groundwater. In Illinois, MTBE has been found in 26 of the 1,800 public water supplies. MTBE has also been blended in Mexico into two types of gasoline sold in the country by the state oil company (PEMEX) but is not monitored in groundwater at this time. Early research on MTBE considered it unable to adsorb to soils and sediments, however, by increasing the organic matter and decreasing the size of the grains (silts or clays) this may increase sorption. The objective of this study is to determine if fine grained materials have the potential for sorption of MTBE due to its high specific surface area (10-700 m 2/g) and potentially high organic matter (0.5-3.8%). The experiment consisted of sorption isotherms to glacial tills from DeKalb, Illinois and lacustrine clays from Chalco, Mexico. Experiments were performed with various concentrations of MTBE and benzene (10, 50, 100, 500 and 1000 ug/L) at 10° C and 25° C. Results showed a range of values for the distribution coefficient (Kd, linear model). At 10° C the Kd value for MTBE was 0.187 mL/g for lacustrine clay while the glacial loess had a value of 0.009 mL/g. The highest Kd values with MTBE were 0.2859 mL/g for organic rich lacustrine clays and 0.014 mL/g for glacial loess at 25° C. The highest

  1. Hydroxylation of benzene to phenol over magnetic recyclable nanostructured CuFe mixed-oxide catalyst

    CSIR Research Space (South Africa)

    Makgwane, PR

    2015-03-01

    Full Text Available A highly active and magnetically recyclable nanostructured copper–iron oxide (CuFe) catalyst has been synthesized for hydroxylation of benzene to phenol under mild reaction conditions. The obtained catalytic results were correlated with the catalyst...

  2. Spectroscopic investigations of matrix isolated adducts between metal vapors of chromium and benzene

    Science.gov (United States)

    Dalibart, M.; Derouault, J.; Labarrere, H.; Tranquille, M.

    1988-05-01

    UV-visible, infrared and Raman + fluorescence spectra of complexes of Cr with benzene have been investigated using cryogenic techniques. The formation of several different complexes is demonstrated and tentative identifications are proposed.

  3. Reverse isotope dilution method for determining benzene and metabolites in tissues

    International Nuclear Information System (INIS)

    Bechtold, W.E.; Sabourin, P.J.; Henderson, R.F.

    1988-01-01

    A method utilizing reverse isotope dilution for the analysis of benzene and its organic soluble metabolites in tissues of rats and mice is presented. Tissues from rats and mice that had been exposed to radiolabeled benzene were extracted with ethyl acetate containing known, excess quantities of unlabeled benzene and metabolites. Butylated hydroxytoluene was added as an antioxidant. The ethyl acetate extracts were analyzed with semipreparative reversed-phase HPLC. Isolated peaks were collected and analyzed for radioactivity (by liquid scintillation spectrometry) and for mass (by UV absorption). The total amount of each compound present was calculated from the mass dilution of the radiolabeled isotope. This method has the advantages of high sensitivity, because of the high specific activity of benzene, and relative stability of the analyses, because of the addition of large amounts of unlabeled carrier analogue

  4. Transition-Metal-Free Multicomponent Benzannulation Reactions for the Construction of Polysubstituted Benzene Derivatives.

    Science.gov (United States)

    Shu, Wen-Ming; Zheng, Kai-Lu; Ma, Jun-Rui; Wu, An-Xin

    2015-11-06

    A transition-metal-free multicomponent benzannulation reaction was developed from readily available ketones, nitro-olefins, and diester acetylenedicarboxylate. This approach provides a straightforward and efficient way to construct polysubstituted benzene derivatives under mild conditions in high yields.

  5. Correlation between iron mobilization and emergence of benzene in leachate at old landfills.

    Science.gov (United States)

    Tansel, Berrin

    2013-05-15

    Leachate monitoring data from a closed municipal solid waste (MSW) landfill with negligible gas production showed increasing iron, alkalinity and benzene levels over time. Due to significant rain water infiltration, concentration data alone was not adequate to analyze the possible correlations between the leachate quality parameters monitored. When quantities (kg/d) present in leachate rather than concentrations (mg/L) of benzene, bicarbonate and iron were analyzed; there were significant correlations between benzene and iron as well as biocarbonate and iron quantities. Increasing iron quantity in leachate was accompanied by increasing quantities of benzene and bicarbonate which are indicative of transformation reactions of polymeric organic compounds present in MSW. The results indicate that biotransformation mechanisms in landfills are similar to those in anaerobic sediments due to lack of electron acceptors with higher energy yields. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Inhibition of Ps Formation in Benzene and Cyclohexane by CH3CI and CH3Br

    DEFF Research Database (Denmark)

    Wikander, G.; Mogensen, O. E.; Pedersen, Niels Jørgen

    1983-01-01

    Positron-annihilation lifetime spectra have been measured for mixtures of CH3Cl and CH3Br in cyclohexane and of CH3Cl in benzene. The ortho-positronium (Ps) yield decreased monotonically from 38% and 43% in cyclohexane and benzene respectively to 11% in pure CH3Cl and 6% in pure CH3Br. The strength......− anions to form Ps. while it forms a bound state with the halides. X−. CH3Cl was a roughly three times weaker Ps inhibitor in benzene than in cyclohexane, which shows that CH3Cl− does not dechlorinate in times comparable to or shorter than 400–500 ps in benzene. An improved model for the explanation of Ps...

  7. A system for the analysis of tritium content in natural waters, through benzene

    International Nuclear Information System (INIS)

    Bocchi, N.

    1980-01-01

    A system is described for the analysis of tritium ( 3 H) in natural waters. The system consists of an electrolytic enrichment equipment and a vacuum line for benzene synthesis. The benzene is mixed with a scintillating solution and so used in tritium activity measurements by liquid scintillation spectrometry. The characteristcs of the system, as well as its performance, are pointed out through analysis of ground and rain waters. The precision and reproducibility of the measurements are discussed. (Author) [pt

  8. Disturbance response indicators of Impatiens walleriana exposed to benzene and chromium.

    Science.gov (United States)

    Campos, V; Lessa, S S; Ramos, R L; Shinzato, M C; Medeiros, T A M

    2017-08-03

    The purpose of this study was to evaluate the remediation potential and disturbance response indicators of Impatiens walleriana exposed to benzene and chromium. Numerous studies over the years have found abundant evidence of the carcinogenicity of benzene and chromium (VI) in humans. Benzene and chromium are two toxic industrial chemicals commonly found together at contaminated sites, and one of the most common management strategies employed in the recovery of sites contaminated by petroleum products and trace metals is in situ remediation. Given that increasing interest has focused on the use of plants as depollution agents, direct injection tests and benzene misting were performed on I. walleriana to evaluate the remediation potential of this species. I. walleriana accumulated hexavalent chromium, mainly in the root system (164.23 mg kg -1 ), to the detriment of the aerial part (39.72 mg kg -1 ), and presented visible damage only at the highest concentration (30 mg L -1 ). Unlike chromium (VI), chromium (III) was retained almost entirely by the soil, leaving it available for removal by phytotechnology. However, after the contamination stopped, I. walleriana responded positively to the detoxification process, recovering its stem stiffness and leaf color. I. walleriana showed visible changes such as leaf chlorosis during the ten days of benzene contamination. When benzene is absorbed by the roots, it is translocated to and accumulated in the plant's aerial part. This mechanism the plant uses ensures its tolerance to the organic compound, enabling the species to survive and reproduce after treatment with benzene. Although I. walleriana accumulates minor amounts of hexavalent chromium in the aerial part, this amount suffices to induce greater oxidative stress and to increase the amount of hydrogen peroxide when compared to that of benzene. It was therefore concluded that I. walleriana is a species that possesses desirable characteristics for phytotechnology.

  9. Partial Hydrogenation of Benzene to Cyclohexene over Ru-Zn/MCM-41

    OpenAIRE

    Zhang, Tongtong; Wang, Zhimiao; Zhao, Qingqing; Li, Fang; Xue, Wei

    2015-01-01

    Ru-Zn/MCM-41 catalysts for the partial hydrogenation of benzene with differing Zn contents were prepared by the incipient-wetness impregnation method. The evaluation results indicate that Zn simultaneously depresses the catalysts activity and cyclohexene selectivity. This can be attributed to the change in the amount of the different hydrogenation sites affected by Zn. The weak hydrogenation sites can promote benzene conversion, and the strong hydrogenation sites, a novel kind of hydrogenatio...

  10. Disproportionation of Trimethyl Benzenes over Large Pore Zeolites: Catalytic and Adsorption Study

    Czech Academy of Sciences Publication Activity Database

    Čejka, Jiří; Kotrla, Josef; Krejčí, Andrea

    2004-01-01

    Roč. 277, 1/2 (2004), s. 191-199 ISSN 0926-860X R&D Projects: GA ČR GA104/99/0840; GA AV ČR IBS4040015 Institutional research plan: CEZ:AV0Z4040901 Keywords : trimethyl benzenes * xylenes * tetramethyl benzenes * disproportionation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.378, year: 2004

  11. Hydrogeologic characterization and assessment of bioremediation of chlorinated benzenes and benzene in wetland areas, Standard Chlorine of Delaware, Inc. Superfund Site, New Castle County, Delaware, 2009-12

    Science.gov (United States)

    Lorah, Michelle M.; Walker, Charles W.; Baker, Anna C.; Teunis, Jessica A.; Emily Majcher,; Brayton, Michael J.; Raffensperger, Jeff P.; Cozzarelli, Isabelle M.

    2015-01-01

    Wetlands at the Standard Chlorine of Delaware, Inc. Superfund Site (SCD) in New Castle County, Delaware, are affected by contamination with chlorobenzenes and benzene from past waste storage and disposal, spills, leaks, and contaminated groundwater discharge. In cooperation with the U.S. Environmental Protection Agency, the U.S. Geological Survey began an investigation in June 2009 to characterize the hydrogeology and geochemistry in the wetlands and assess the feasibility of monitored natural attenuation and enhanced bioremediation as remedial strategies. Groundwater flow in the wetland study area is predominantly vertically upward in the wetland sediments and the underlying aquifer, and groundwater discharge accounts for a minimum of 47 percent of the total discharge for the subwatershed of tidal Red Lion Creek. Thus, groundwater transport of contaminants to surface water could be significant. The major contaminants detected in groundwater in the wetland study area included benzene, monochlorobenzene, and tri- and di-chlorobenzenes. Shallow wetland groundwater in the northwest part of the wetland study area was characterized by high concentrations of total chlorinated benzenes and benzene (maximum about 75,000 micrograms per liter [μg/L]), low pH, and high chloride. In the northeast part of the wetland study area, wetland groundwater had low to moderate concentrations of total chlorinated benzenes and benzene (generally not greater than 10,000 μg/L), moderate pH, and high sulfate concentrations. Concentrations in the groundwater in excess of 1 percent of the solubility of the individual chlorinated benzenes indicate that a contaminant source is present in the wetland sediments as dense nonaqueous phase liquids (DNAPLs). Consistently higher contaminant concentrations in the shallow wetland groundwater than deeper in the wetland sediments or the aquifer also indicate a continued source in the wetland sediments, which could include dissolution of DNAPLs and

  12. Risks to the offspring from parental occupational exposures

    International Nuclear Information System (INIS)

    Haas, J.F.; Schottenfeld, D.

    1979-01-01

    Risks to the offspring of workers with occupational chemical exposures may derive from mutagenic, teratogenic or carcinogenic effects of industrial agents to which the parents are exposed. Evidence for impaired pregnancies and hazards to the offspring of working populations with chemical exposures is, however, very limited. Evidence is reviewed for hazards to the offspring resulting from parental occupational exposure to vinyl chloride, benzene, chloroprene, radiation and petroleum-derived hydrocarbons. Other environmental and behavioral factors with major effects on pregnancy outcome are considered. These include smoking, alcohol, and drug exposures. An approach to surveillance for chromosomal abnormalities in offspring of occupationally exposed parents is outlined

  13. Understanding the properties of inorganic benzenes based on π-electron densities.

    Science.gov (United States)

    Wu, Wenjie; Li, Xiaoyan; Meng, Lingpeng; Zheng, Shijun; Zeng, Yanli

    2015-03-12

    The properties of inorganic benzenes have been investigated by means of second-order Møller-Plesset perturbation theory (MP2) calculations and quantum theory of atoms in molecules (QTAIM) studies. In this work, the σ- and π-electron densities were separated from the total electron densities, and it was therefore possible to evaluate the contributions of σ and π electrons to the chemical bonds and properties of inorganic benzenes. The following conclusions are given: (1) The π-attractors' positions correlate to their respective atomic radii. With increasing atomic number in the same period, the attractor of π-electron densities becomes closer to its respective nucleus. With increasing atomic number in the main group, the position of the π attractor becomes farther from its respective nucleus. (2) The strength of the chemical bonds of the inorganic benzene rings is determined by σ-electron densities, not π-electron densities; their bonding character is mainly determined by the σ-electron density; however, the role of the π-electron density cannot be neglected. (3) For the inorganic benzenes studied, the electron localization function for π (ELFπ) values are related to the differences of the electronegativity between the neighboring atoms of the inorganic benzene rings, Δχ(X,Y). The smaller the difference of Δχ(X,Y), the higher the value of ELFπ, resulting in more aromatic properties of the inorganic benzenes.

  14. Investigation into adsorption and photocatalytic degradation of gaseous benzene in an annular fluidized bed photocatalytic reactor.

    Science.gov (United States)

    Geng, Qijin; Tang, Shankang; Wang, Lintong; Zhang, Yunchen

    2015-01-01

    The adsorption and photocatalytic degradation of gaseous benzene were investigated considering the operating variables and kinetic mechanism using nano-titania agglomerates in an annular fluidized bed photocatalytic reactor (AFBPR) designed. The special adsorption equilibrium constant, adsorption active sites, and apparent reaction rate coefficient of benzene were determined by linear regression analysis at various gas velocities and relative humidities (RH). Based on a series of photocatalytic degradation kinetic equations, the influences of operating variables on degradation efficiency, apparent reaction rate coefficient and half-life were explored. The findings indicated that the operating variables have obviously influenced the adsorption/photocatalytic degradation and corresponding kinetic parameters. In the photocatalytic degradation process, the relationship between photocatalytic degradation efficiency and RH indicated that water molecules have a dual-function which was related to the structure characteristics of benzene. The optimal operating conditions for photocatalytic degradation of gaseous benzene in AFBPR were determined as the fluidization number at 1.9 and RH required related to benzene concentration. This investigation highlights the importance of controlling RH and benzene concentration in order to obtain the desired synergy effect in photocatalytic degradation processes.

  15. Geogenic sources of benzene in aquifers used for public supply, California

    Science.gov (United States)

    Landon, Matthew K.; Belitz, Kenneth

    2012-01-01

    Statistical evaluation of two large statewide data sets from the California State Water Board's Groundwater Ambient Monitoring and Assessment Program (1973 wells) and the California Department of Public Health (12417 wells) reveals that benzene occurs infrequently (1.7%) and at generally low concentrations (median detected concentration of 0.024 μg/L) in groundwater used for public supply in California. When detected, benzene is more often related to geogenic (45% of detections) than anthropogenic sources (27% of detections). Similar relations are evident for the sum of 17 hydrocarbons analyzed. Benzene occurs most frequently and at the highest concentrations in old, brackish, and reducing groundwater; the detection frequency was 13.0% in groundwater with tritium 1600 μS/cm, and anoxic conditions. This groundwater is typically deep (>180 m). Benzene occurs somewhat less frequently in recent, shallow, and reducing groundwater; the detection frequency was 2.6% in groundwater with tritium ≥1 pCi/L, depth benzene include: higher concentrations and detection frequencies with increasing well depth, groundwater age, and proximity to oil and gas fields; and higher salinity and lower chloride/iodide ratios in old groundwater with detections of benzene, consistent with interactions with oil-field brines.

  16. Investigation on minimum ignition energy of mixtures of α-pinene-benzene/air.

    Science.gov (United States)

    Coudour, B; Chetehouna, K; Rudz, S; Gillard, P; Garo, J P

    2015-01-01

    Minimum ignition energies (MIE) of α-pinene-benzene/air mixtures at a given temperature for different equivalence ratios and fuel proportions are experimented in this paper. We used a cylindrical chamber of combustion using a nanosecond pulse at 1,064 nm from a Q-switched Nd:YAG laser. Laser-induced spark ignitions were studied for two molar proportions of α-pinene/benzene mixtures, respectively 20-80% and 50-50%. The effect of the equivalence ratio (Φ) has been investigated for 0.7, 0.9, 1.1 and 1.5 and ignition of fuel/air mixtures has been experimented for two different incident laser energies: 25 and 33 mJ. This study aims at observing the influence of different α-pinene/benzene proportions on the flammability of the mixture to have further knowledge of the potential of biogenic volatile organic compounds (BVOCs) and smoke mixtures to influence forest fires, especially in the case of the accelerating forest fire phenomenon (AFF). Results of ignition probability and energy absorption are based on 400 laser shots for each studied fuel proportions. MIE results as functions of equivalence ratio compared to data of pure α-pinene and pure benzene demonstrate that the presence of benzene in α-pinene-air mixture tends to increase ignition probability and reduce MIE without depending strongly on the α-pinene/benzene proportion. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Vibrationally averaged dipole moments of methane and benzene isotopologues

    Energy Technology Data Exchange (ETDEWEB)

    Arapiraca, A. F. C. [Laboratório de Átomos e Moléculas Especiais, Departamento de Física, ICEx, Universidade Federal de Minas Gerais, P. O. Box 702, 30123-970 Belo Horizonte, MG (Brazil); Centro Federal de Educação Tecnológica de Minas Gerais, Coordenação de Ciências, CEFET-MG, Campus I, 30.421-169 Belo Horizonte, MG (Brazil); Mohallem, J. R., E-mail: rachid@fisica.ufmg.br [Laboratório de Átomos e Moléculas Especiais, Departamento de Física, ICEx, Universidade Federal de Minas Gerais, P. O. Box 702, 30123-970 Belo Horizonte, MG (Brazil)

    2016-04-14

    DFT-B3LYP post-Born-Oppenheimer (finite-nuclear-mass-correction (FNMC)) calculations of vibrationally averaged isotopic dipole moments of methane and benzene, which compare well with experimental values, are reported. For methane, in addition to the principal vibrational contribution to the molecular asymmetry, FNMC accounts for the surprisingly large Born-Oppenheimer error of about 34% to the dipole moments. This unexpected result is explained in terms of concurrent electronic and vibrational contributions. The calculated dipole moment of C{sub 6}H{sub 3}D{sub 3} is about twice as large as the measured dipole moment of C{sub 6}H{sub 5}D. Computational progress is advanced concerning applications to larger systems and the choice of appropriate basis sets. The simpler procedure of performing vibrational averaging on the Born-Oppenheimer level and then adding the FNMC contribution evaluated at the equilibrium distance is shown to be appropriate. Also, the basis set choice is made by heuristic analysis of the physical behavior of the systems, instead of by comparison with experiments.

  18. BENZENE FORMATION ON INTERSTELLAR ICY MANTLES CONTAINING PROPARGYL ALCOHOL

    International Nuclear Information System (INIS)

    Sivaraman, B.; Mukherjee, R.; Subramanian, K. P.; Banerjee, S. B.

    2015-01-01

    Propargyl alcohol (CHCCH 2 OH) is a known stable isomer of the propenal (CH 2 CHCHO) molecule that was reported to be present in the interstellar medium (ISM). At astrochemical conditions in the laboratory, icy layers of propargyl alcohol grown at 85 K were irradiated by 2 keV electrons and probed by a Fourier Transform InfraRed spectrometer in the mid-infrared (IR) region, 4000-500 cm –1 . Propargyl alcohol ice under astrochemical conditions was studied for the first time; therefore, IR spectra of reported amorphous (85 K) and crystalline (180 K) propargyl alcohol ices can be used to detect its presence in the ISM. Moreover, our experiments clearly show benzene (C 6 H 6 ) formation to be the major product from propargyl alcohol irradiation, confirming the role of propargyl radicals (C 3 H 3 ) formed from propargyl alcohol dissociation that was long expected based on theoretical modeling to effectively synthesize C 6 H 6 in the interstellar icy mantles

  19. BENZENE FORMATION ON INTERSTELLAR ICY MANTLES CONTAINING PROPARGYL ALCOHOL

    Energy Technology Data Exchange (ETDEWEB)

    Sivaraman, B.; Mukherjee, R.; Subramanian, K. P.; Banerjee, S. B., E-mail: bhala@prl.res.in [Space and Atmospheric Sciences Division, Physical Research Laboratory, Ahmedabad (India)

    2015-01-10

    Propargyl alcohol (CHCCH{sub 2}OH) is a known stable isomer of the propenal (CH{sub 2}CHCHO) molecule that was reported to be present in the interstellar medium (ISM). At astrochemical conditions in the laboratory, icy layers of propargyl alcohol grown at 85 K were irradiated by 2 keV electrons and probed by a Fourier Transform InfraRed spectrometer in the mid-infrared (IR) region, 4000-500 cm{sup –1}. Propargyl alcohol ice under astrochemical conditions was studied for the first time; therefore, IR spectra of reported amorphous (85 K) and crystalline (180 K) propargyl alcohol ices can be used to detect its presence in the ISM. Moreover, our experiments clearly show benzene (C{sub 6}H{sub 6}) formation to be the major product from propargyl alcohol irradiation, confirming the role of propargyl radicals (C{sub 3}H{sub 3}) formed from propargyl alcohol dissociation that was long expected based on theoretical modeling to effectively synthesize C{sub 6}H{sub 6} in the interstellar icy mantles.

  20. Anaerobic degradation of alkylated benzenes in denitrifying laboratory aquifer columns

    International Nuclear Information System (INIS)

    Kuhn, E.P.; Zeyer, J.; Eicher, P.; Schwarzenbach, R.P.

    1988-01-01

    Toluene and m-xylene were rapidly mineralized in an anaerobic laboratory aquifer column operated under continuous-flow conditions with nitrate as an electron acceptor. The oxidation of toluene and m-xylene was coupled with the reduction of nitrate, and mineralization was confirmed by trapping 14 CO 2 evolved from 14 C-ring-labeled substrates. Substrate degradation also took place when nitrous oxide replaced nitrate as an electron acceptor, but decomposition was inhibited in the presence of molecular oxygen or after the substitution of nitrate by nitrite. The m-xylene-adapted microorganisms in the aquifer column degraded toluene, benzaldehyde, benzoate, m-toluylaldehyde, m-toluate, m-cresol, p-cresol, and p-hydroxybenzoate but were unable to metabolize benzene, naphthalene, methylcyclohexane, and 1,3-dimethylcyclohexane. Isotope-dilution experiments suggested benzoate as an intermediate formed during anaerobic toluene metabolism. The finding that the highly water-soluble nitrous oxide served as electron acceptor for the anaerobic mineralization of some aromatic hydrocarbons may offer attractive options for the in situ restoration of polluted aquifers

  1. Electron localization in a mixed-valence diniobium benzene complex.

    Science.gov (United States)

    Gianetti, Thomas L; Nocton, Grégory; Minasian, Stefan G; Kaltsoyannis, Nikolas; Kilcoyne, A L David; Kozimor, Stosh A; Shuh, David K; Tyliszczak, Tolek; Bergman, Robert G; Arnold, John

    2015-02-01

    Reaction of the neutral diniobium benzene complex {[Nb(BDI)N t Bu] 2 (μ-C 6 H 6 )} (BDI = N , N '-diisopropylbenzene-β-diketiminate) with Ag[B(C 6 F 5 ) 4 ] results in a single electron oxidation to produce a cationic diniobium arene complex, {[Nb(BDI)N t Bu] 2 (μ-C 6 H 6 )}{B(C 6 F 5 ) 4 }. Investigation of the solid state and solution phase structure using single-crystal X-ray diffraction, cyclic voltammetry, magnetic susceptibility, and multinuclear NMR spectroscopy indicates that the oxidation results in an asymmetric molecule with two chemically inequivalent Nb atoms. Further characterization using density functional theory (DFT) calculations, UV-visible, Nb L 3,2 -edge X-ray absorption near-edge structure (XANES), and EPR spectroscopies supports assignment of a diniobium complex, in which one Nb atom carries a single unpaired electron that is not largely delocalized on the second Nb atom. During the oxidative transformation, one electron is removed from the δ-bonding HOMO, which causes a destabilization of the molecule and formation of an asymmetric product. Subsequent reactivity studies indicate that the oxidized product allows access to metal-based chemistry with substrates that did not exhibit reactivity with the starting neutral complex.

  2. (η6-Benzenedichlorido(dicyclohexylphenylphosphaneruthenium(II benzene sesquisolvate

    Directory of Open Access Journals (Sweden)

    Alfred Muller

    2012-12-01

    Full Text Available The asymmetric unit of the title compound, [RuCl2(C6H6(C18H27P]·1.5C6H6, contains one molecule of the RuII complex and one and a half solvent molecules as one of these is located about a centre of inversion. The RuII atom has a classical three-legged piano-stool environment being coordinated by an η6-benzene ligand [Ru—centroid = 1.6964 (6 Å], two chloride ligands with an average Ru—Cl bond length of 2.4138 (3 Å and a dicyclohexylphenylphosphane ligand [Ru—P = 2.3786 (3 Å]. The effective cone angle for the phosphane was calculated to be 158°. In the crystal, weak C—H...Cl hydrogen bonds link the RuII complexes into centrosymmetric dimers. The crystal packing exhibits intra- and intermolecular C—H...π interactions resulting in a zigzag pattern in the [101] direction.

  3. Amidine Sulfonamides and Benzene Sulfonamides: Synthesis and Their Biological Evaluation

    Directory of Open Access Journals (Sweden)

    Muhammad Abdul Qadir

    2015-01-01

    Full Text Available New amidine and benzene sulfonamide derivatives were developed and structures of the new products were confirmed by elemental and spectral analysis (FT-IR, ESI-MS, 1HNMR, and 13CNMR. In vitro, developed compounds were screened for their antibacterial and antifungal activities against medically important bacterial strains, namely, S. aureus, B. subtilis, and E. coli, and fungi, namely, A. flavus, A. parasiticus, and A. sp. The antibacterial and antifungal activities have been determined by measuring MIC values (μg/mL and zone of inhibitions (mm. Among the tested compounds, it was found that compounds 3b, 9a, and 9b have most potent activity against S. aureus, A. flavus, and A. parasiticus, respectively, and were found to be more active than sulfamethoxazole and itraconazole with MIC values 40 μg/mL. In contrast, all the compounds were totally inactive against the A. sp. except 10b and 15b to show activity to some extent.

  4. Platinum nanoparticle shape effects on benzene hydrogenation selectivity.

    Science.gov (United States)

    Bratlie, Kaitlin M; Lee, Hyunjoo; Komvopoulos, Kyriakos; Yang, Peidong; Somorjai, Gabor A

    2007-10-01

    Benzene hydrogenation was investigated in the presence of a surface monolayer consisting of Pt nanoparticles of different shapes (cubic and cuboctahedral) and tetradecyltrimethylammonium bromide (TTAB). Infrared spectroscopy indicated that TTAB binds to the Pt surface through a weak C-H...Pt bond of the alkyl chain. The catalytic selectivity was found to be strongly affected by the nanoparticle shape. Both cyclohexane and cyclohexene product molecules were formed on cuboctahedral nanoparticles, whereas only cyclohexane was produced on cubic nanoparticles. These results are the same as the product selectivities obtained on Pt(111) and Pt(100) single crystals in earlier studies. The apparent activation energy for cyclohexane production on cubic nanoparticles is 10.9 +/- 0.4 kcal/mol, while for cuboctahedral nanoparticles, the apparent activation energies for cyclohexane and cyclohexene production are 8.3 +/- 0.2 and 12.2 +/- 0.4 kcal/mol, respectively. These activation energies are lower, and corresponding turnover rates are three times higher than those obtained with single-crystal Pt surfaces.

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

    Directory of Open Access Journals (Sweden)

    Raeesa Moolla

    2015-04-01

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

  6. Chemopreventive Potential of Major Flavonoid Compound of Methanolic Bark Extract ofSaraca asoca(Roxb.) in Benzene-induced Toxicity of Acute Myeloid Leukemia Mice.

    Science.gov (United States)

    Mukhopadhyay, Manas Kumar; Shaw, Mithun; Nath, Debjani

    2017-07-01

    Saraca asoca (SA) (Roxb.) is one of the folk medicinal plants found in India, Bangladesh, and Sri Lanka. Its major biological activity appears due to the presence of flavonoid group of compounds in its bark extract. In this study, our research aims to analyze the chemopreventive effect of flavonoids, especially a natural phenol catechin present in the bark methanolic extract of SA on acute myeloid leukemia (AML) mice. The total bark extract was partitioned and analyzed on thin-layer chromatography (TLC) plate. The yellow-brown material of spot 4 was analyzed and identified as catechin. The yellowish brown material (YBM) was tested for their chemopreventive potential. An in vivo AML mice model was used to test the efficacy. Hematological parameters (Hb %, red blood cell, and white blood cell count), expression of cell cycle regulatory proteins, and DNA fragmentation analysis were performed. After treatment of benzene-exposed mice with the major flavonoid compound, namely catechin, the above parameters increase significantly ( P YBM), like doxorubicin, can act as the neutralizer and protector of mortality in cancer cases. The catechin from methanolic bark extract of Saraca asoca has chemoprotective activity in benzene-induced secondary acute myeloid leukemia.(AML) in bone marrowHematological parameters, structural analysis of DNA showed that the purified catechin attenuates the conditions responsible for the development of AMLThe purified flavonol, catechin has a modulatory effect on different cell cycle deregulations induced by benzene in AML model.

  7. Volatility of the catalytic hydrogenation products of 1,4 bis(phenylethynyl)benzene

    Science.gov (United States)

    Sharma, Hom N.; Sangalang, Elizabeth A.; Saw, Cheng K.; Cairns, Gareth A.; McLean, William; Maxwell, Robert S.; Dinh, Long N.

    2017-11-01

    Measurements of equilibrium vapor pressures by effusion thermogravimetry and melting points by differential scanning calorimetry reveal that the melting temperature and equilibrium vapor pressures of 1,4-bis(phenylethynyl)benzene (DEB) do not vary monotonically with the hydrogenation extent. Contrary to intuition which suggests increasing volatility with hydrogenation, results indicate decreasing volatility for the first two hydrogenation steps before a non-monotonic upward trend, in which trans-isomers are less volatile. Insights on structural packing and functional groups were obtained from x-ray diffraction and infrared studies to shed light on the observed variation in the volatility of DEB with hydrogenation. Density functional theory calculations were performed to obtain molecular level information and to establish the thermodynamics of DEB hydrogenation reactions. A major factor influencing the observed melting points and volatility of the hydrogenated intermediate species is identified as the local attractive or repulsive carbon-hydrogen (CH) dipole interactions among the getter molecules in their respective crystal structures. Such collective CH dipole interactions can be used to predict the trends in the volatilities of catalytic hydrogenation processes.

  8. Angiogenic potential of 3-nitro-4-hydroxy benzene arsonic acid (roxarsone).

    Science.gov (United States)

    Basu, Partha; Ghosh, Richik N; Grove, Linnette E; Klei, Linda; Barchowsky, Aaron

    2008-04-01

    Roxarsone (3-nitro-4-hydroxy benzene arsonic acid) is an arsenic compound widely used in the poultry industry as a feed additive to prevent coccidiosis, stimulate growth, and to improve tissue pigmentation. Little is known about the potential human health effects from roxarsone released into the environment from chicken waste or from residual compound in chicken products. The growth potentiation and enhanced tissue pigmentation suggest that low levels of roxarsone exposure may have an angiogenic potential similar to that of inorganic arsenite (As(III)). The goal of this investigation was to test the hypothesis described above using cultured human aortic and lung microvascular endothelial cells in high-content imaging tube-forming assays and begin developing a molecular level understanding of the process. We used a three-dimensional Matrigel assay for probing angiogenesis in cultured human endothelial cells, and a polymerase chain reaction (PCR) array to probe the gene changes as a function of roxarsone or As(III) treatment. In addition, we used Western blot analysis for changes in protein concentration and activation. Roxarsone was found to exhibit a higher angiogenic index than As(III) at lower concentrations. Increased endothelial nitric oxide synthase (eNOS) activity was observed for roxarsone but not for As(III)-induced angiogenesis. However, As(III) caused more rapid and pronounced phosphorylation of eNOS. Quantitative PCR array on select genes revealed that the two compounds have different and often opposite effects on angiogenic gene expression. The results demonstrate that roxarsone and As(III) promote angiogenic phenotype in human endothelial cells through distinctly different signaling mechanisms.

  9. Variable products in dielectric-barrier discharge assisted benzene oxidation.

    Science.gov (United States)

    Dey, G R; Sharma, Asmita; Pushpa, K K; Das, Tomi Nath

    2010-06-15

    Atmospheric-pressure dielectric-barrier discharge (DBD) assisted control of benzene((g)) oxidation into different classes of products is presented in this study. The gas-phase products were directly analyzed online by GC-FID and GC-MS. In addition, a solid yellowish surface deposit also formed, which was dissolved in 10 mL ethanol after each 10 min DBD cycle for GC analyses. One of the gas-phase products, phenol was also separately collected and estimated by Folin-Ciocalteu's wet-colorimetric method. In the gas phase only phenol and biphenyl were detected at maximum total conversion of approximately 3%, while in the ethanolic solution furthermore 1,2- and 1,4-dihydroxybenzene, 2,2'-biphenol, 2- and 4-phenylphenol and 4-phenoxyphenol were estimated at microM to mM level, and reveal approximately 30% total conversion. Products' types hint at the phenyl radical as the primary precursor. However, with the use of mesoporous molecular sieve 10X packing in unison with DBD, while the concentrations of such phenolic products decreased drastically, a number of open chain and non-aromatic ethers, aldehydes and esters, and also naphthalene and biphenylene were formed. In addition to high DBD process efficiency, the latter results suggest modification of discharge characteristics, and also strong physicochemical effects of cavity size and surface property on the intermediate reactions therein. Thus, use of such packing highlights a novel and practical methodology for control of chemical reactions towards useful product types, vis-à-vis pollutant mitigation. Copyright 2010 Elsevier B.V. All rights reserved.

  10. Simulation of the (vapor + liquid) equilibria of binary mixtures of benzene, cyclohexane, and hydrogen

    International Nuclear Information System (INIS)

    Carrero-Mantilla, J.

    2008-01-01

    Molecular simulations of the (vapor + liquid) equilibria (VLE) for benzene, cyclohexane, and (benzene + hydrogen) and (cyclohexane + hydrogen) were carried out using the Gibbs-ensemble Monte Carlo method with configurational bias. The Buckingham exponential six (exp-6) potential was used for the site-site interactions with no binary interaction parameters; benzene and cyclohexane were described with six interaction sites, and hydrogen with a single site. Simulation results, density, pressure, and vaporization enthalpy for benzene and cyclohexane were in reasonable agreement with experimental data, but critical pressures obtained from extrapolation of the VLE results did not match the experimental values. For (benzene + hydrogen) and (cyclohexane + hydrogen) mixtures mole fractions from simulation were compared with experimental data, the results for liquid phase were in closer agreement with experiment than the results for vapor phase. For the mixtures, results from the PSRK equation of state (PSRK-EOS) predicted the mole fractions for both phases, also vapor densities from molecular simulation were in close agreement with PSRK-EOS. Additionally, the Henry's law constant (K H ) for hydrogen was calculated in separate simulations using test particle insertions, and qualitative agreement with values from experimental VLE data was obtained. For the (benzene + hydrogen) system K H results from PSRK-EOS were cl