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Sample records for benzene exposure identified

  1. 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.

  2. Benzene exposures in urban areas

    International Nuclear Information System (INIS)

    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/m3, current European air quality guideline for this carcinogenic compound

  3. Biomarkers of environmental benzene exposure.

    OpenAIRE

    Weisel, C; Yu, R; Roy, A; Georgopoulos, P.

    1996-01-01

    Environmental exposures to benzene result in increases in body burden that are reflected in various biomarkers of exposure, including benzene in exhaled breath, benzene in blood and urinary trans-trans-muconic acid and S-phenylmercapturic acid. A review of the literature indicates that these biomarkers can be used to distinguish populations with different levels of exposure (such as smokers from nonsmokers and occupationally exposed from environmentally exposed populations) and to determine d...

  4. Variability of benzene exposure among filling station attendants

    International Nuclear Information System (INIS)

    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

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

    International Nuclear Information System (INIS)

    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

  6. Benzene exposure: An overview of monitoring methods and their findings

    OpenAIRE

    Weisel, Clifford P.

    2010-01-01

    Benzene has been measured throughout the environment and is commonly emitted in several industrial and transportation settings leading to widespread environmental and occupational exposures. Inhalation is the most common exposure route but benzene rapidly penetrates the skin and can contaminant water and food resulting in dermal and ingestion exposures. While less toxic solvents have been substituted for benzene, it still is a component of petroleum products, including gasoline, and is a trac...

  7. Benzene exposure: an overview of monitoring methods and their findings.

    Science.gov (United States)

    Weisel, Clifford P

    2010-03-19

    Benzene has been measured throughout the environment and is commonly emitted in several industrial and transportation settings leading to widespread environmental and occupational exposures. Inhalation is the most common exposure route but benzene rapidly penetrates the skin and can contaminant water and food resulting in dermal and ingestion exposures. While less toxic solvents have been substituted for benzene, it still is a component of petroleum products, including gasoline, and is a trace impurity in industrial products resulting in continued sub to low ppm occupational exposures, though higher exposures exist in small, uncontrolled workshops in developing countries. Emissions from gasoline/petrochemical industry are its main sources to the ambient air, but a person's total inhalation exposure can be elevated from emissions from cigarettes, consumer products and gasoline powered engines/tools stored in garages attached to homes. Air samples are collected in canisters or on adsorbent with subsequent quantification by gas chromatography. Ambient air concentrations vary from sub-ppb range, low ppb, and tens of ppb in rural/suburban, urban, and source impacted areas, respectively. Short-term environmental exposures of ppm occur during vehicle fueling. Indoor air concentrations of tens of ppb occur in microenvironments containing indoor sources. Occupational and environmental exposures have declined where regulations limit benzene in gasoline (<1%) and cigarette smoking has been banned from public and work places. Similar controls should be implemented worldwide to reduce benzene exposure. Biomarkers of benzene used to estimate exposure and risk include: benzene in breath, blood and urine; its urinary metabolites: phenol, t,t-muconic acid (t,tMA) and S-phenylmercapturic acid (sPMA); and blood protein adducts. The biomarker studies suggest benzene environmental exposures are in the sub to low ppb range though non-benzene sources for urinary metabolites, differences

  8. Benzene exposure is associated with epigenetic changes (Review).

    Science.gov (United States)

    Fenga, Concettina; Gangemi, Silvia; Costa, Chiara

    2016-04-01

    Benzene is a volatile aromatic hydrocarbon solvent and is known as one of the predominant air pollutants in the environment. Chronic exposure to benzene is known to cause aplastic anemia and increased risk of acute myelogenous leukemia in humans. Although the mechanisms by which benzene causes toxicity remain to be fully elucidated, it is widely accepted that its metabolism is crucial to its toxicity, with involvement of one or more reactive metabolites. Novel approaches aimed at evaluating different mechanisms by which benzene can impact on human health by altering gene regulation have been developed. Among these novel approaches, epigenetics appears to be promising. The present review article summarizes the most important findings, reported from the literature, on epigenetic modifications correlated to benzene exposure. A computerized search in PubMed was performed in November 2014, using search terms, including 'benzene', 'epigenetic', 'histone modifications', 'DNA methylation' and 'microRNA'. Epidemiological and experimental studies have demonstrated the potential epigenetic effects of benzene exposure. Several of the epigenomic changes observed in response to environmental exposures may be mechanistically associated with susceptibility to diseases. However, further elucidation of the mechanisms by which benzene alters gene expression may improve prediction of the toxic potential of novel compounds introduced into the environment, and allow for more targeted and appropriate disease prevention strategies. PMID:26936331

  9. Variability of benzene exposure among filling station attendants; Variabilita` dell`esposizione a benzene tra gli addetti all`erogazione di carburanti

    Energy Technology Data Exchange (ETDEWEB)

    Carere, A.; Iacovella, N.; Turrio Baldassarri, L. [Istituto Superiore di Sanita`, Rome (Italy). Lab. di Tossicologia Comparata ed Ecotossicologia; Fuselli, S.; Iavarone, I.; Lagorio, S.; Proietto, A.R. [Istituto Superiore di Sanita`, Rome (Italy). Lab. di Igiene Ambientale

    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.

  10. Exposure to benzene metabolites causes oxidative damage in Saccharomyces cerevisiae.

    Science.gov (United States)

    Raj, Abhishek; Nachiappan, Vasanthi

    2016-06-01

    Hydroquinone (HQ) and benzoquinone (BQ) are known benzene metabolites that form reactive intermediates such as reactive oxygen species (ROS). This study attempts to understand the effect of benzene metabolites (HQ and BQ) on the antioxidant status, cell morphology, ROS levels and lipid alterations in the yeast Saccharomyces cerevisiae. There was a reduction in the growth pattern of wild-type cells exposed to HQ/BQ. Exposure of yeast cells to benzene metabolites increased the activity of the anti-oxidant enzymes catalase, superoxide dismutase and glutathione peroxidase but lead to a decrease in ascorbic acid and reduced glutathione. Increased triglyceride level and decreased phospholipid levels were observed with exposure to HQ and BQ. These results suggest that the enzymatic antioxidants were increased and are involved in the protection against macromolecular damage during oxidative stress; presumptively, these enzymes are essential for scavenging the pro-oxidant effects of benzene metabolites. PMID:27016252

  11. Lymphocyte chromosome breakage in low benzene exposure among Indonesian workers

    Directory of Open Access Journals (Sweden)

    Dewi S. Soemarko

    2015-01-01

    Full Text Available Background: Benzene has been used in industry since long time and its level in environment should be controled. Although environmental benzene level has been controlled to less than 1 ppm, negative effect of benzene exposure is still observed, such as chromosome breakage. This study aimed to know the prevalence of lymphocyte chromosome breakage and the influencing factors among workers in low level benzene exposure.Methods: This was a cross sectional study in oil & gas industry T, conducted between September 2007 and April 2010. The study subjects consisted of 115 workers from production section and head office. Data on type of work, duration of benzene exposure, and antioxidant consumption were collected by interview as well as observation of working process. Lymphocyte chromosome breakage was examined by banding method. Analysis of relationship between chromosome breakage and risk factors was performed by chi-square and odd ratio, whereas the role of determinant risk factors was analyzed by multivariate forward stepwise.Results: Overall lymphocyte chromosome breakage was experieced by 72 out of 115 subjects (62.61%. The prevalence among workers at production section was 68.9%, while among administration workers was 40% (p > 0.05. Low antioxidant intake increases the risk of chromosome breakage (p = 0.035; ORadjusted = 2.90; 95%CI 1.08-7.78. Other influencing factors are: type of work (p = 0,10; ORcrude = 3.32; 95% CI 1.33-8.3 and chronic benzene exposure at workplace (p = 0.014; ORcrude = 2.61; 95% CI 1.2-5.67, while the work practice-behavior decreases the lymphocyte chromosome breakage (p = 0.007; ORadjusted = 0.30; 95% CI 0.15-0.76.Conclusion: The prevalence of lymphocyte chromosome breakage in the environment with low benzene exposure is quite high especially in production workers. Chronic benzene exposure in the workplace, type of work, and low antioxidant consumption is related to lymphocyte chromosome breakage. Thus, benzene in the

  12. 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.

  13. Association between occupational exposure to benzene and chromosomal alterations in lymphocytes of Brazilian petrochemical workers removed from exposure.

    Science.gov (United States)

    Gonçalves, Rozana Oliveira; de Almeida Melo, Neli; Rêgo, Marco Antônio Vasconcelos

    2016-06-01

    We aimed to investigate the association between chronic exposure to benzene and genotoxicity in the lymphocytes of workers removed from exposure. The study included 20 workers with hematological disorders who had previously worked in the petrochemical industry of Salvador, Bahia, Brazil; 16 workers without occupational exposure to benzene served as the control group. Chromosomal analysis was performed on lymphocytes from peripheral blood, to assess chromosomal breaks and gaps and to identify aneuploidy. The Kruskal-Wallis test was used to compare the mean values between two groups, and Student's t test for comparison of two independent means. The frequency of gaps was statistically higher in and the exposed group than in the controls (2.13 ± 2.86 vs. 0.97 ± 1.27, p = 0.001). The frequency of chromosomal breaks was significantly higher among cases (0.21 ± 0.58) than among controls (0.12 ± 0.4) (p = 0.0002). An association was observed between chromosomal gaps and breaks and occupational exposure to benzene. Our study showed that even when removed from exposure for several years, workers still demonstrated genotoxic damage. Studies are still needed to clarify the long-term genotoxic potential of benzene after removal from exposure. PMID:27155858

  14. Exposure to benzene in urban workers: environmental and biological monitoring of traffic police in Rome

    OpenAIRE

    Crebelli, R; Tomei, F.; Zijno, A; Ghittori, S; M Imbriani; Gamberale, D; Martini, A.; Carere, A

    2001-01-01

    OBJECTIVES—To evaluate the contribution of traffic fumes to exposure to benzene in urban workers, an investigation on personal exposure to benzene in traffic police from the city of Rome was carried out.
METHODS—The study was performed from December 1998 to June 1999. Diffusive Radiello personal samplers were used to measure external exposures to benzene and alkyl benzenes during the workshift in 139 policemen who controlled medium to high traffic areas and in 63 office police. Moreover, as b...

  15. Occupational Exposure to Benzene from Painting with Epoxy and Other High Performance Coatings

    Energy Technology Data Exchange (ETDEWEB)

    JAHN, STEVEN

    2005-04-20

    Following the discovery of trace benzene in paint products, an assessment was needed to determine potential for benzene exposures to exceed the established ACGIH Threshold Limit Value (TLV) during painting operations. Sample data was collected by area industrial hygienists for benzene during routine maintenance and construction activities at Savannah River Site. A set of available data from the IH database, Sentry, was analyzed to provide guidance to the industrial hygiene staff and draw conclusions on the exposure potential during typical painting operations.

  16. Environmental and occupational exposure to benzene by analysis of breath and blood.

    Science.gov (United States)

    Perbellini, L; Faccini, G B; Pasini, F; Cazzoli, F; Pistoia, S; Rosellini, R; Valsecchi, M; Brugnone, F

    1988-05-01

    Benzene exposure of chemical workers was studied, during the entire workshift, by continuous monitoring of workplace benzene concentration, and 16 hours after the end of the workshift by the measurement of alveolar and blood benzene concentrations and excretion of urinary phenol. Exposure of hospital staff was studied by measuring benzene concentrations in the alveolar and blood samples collected during the hospital workshift. Instantaneous environmental air samples were also collected, at the moment of the biological sampling, for all the subjects tested. A group of 34 chemical workers showed an eight hour exposure to benzene, as a geometric mean, of 1.12 micrograms/l which corresponded, 16 hours after the end of the workshift, to a geometric mean benzene concentration of 70 ng/l in the alveolar air and 597 ng/l in the blood. Another group of 27 chemical workers (group A) turned out to be exposed to an indeterminable eight hour exposure to benzene that corresponded, the morning after, to a geometric mean benzene concentration of 28 ng/l in the alveolar air and 256 ng/l in the blood. The group of hospital staff (group B) had a benzene concentration of 14 ng/l in the alveolar air and 269 ng/l in the blood. Instantaneous environmental samples showed that in the infirmaries the geometric mean benzene concentration was 58 ng/l during the examination of the 34 chemical workers, 36 ng/l during the examination of the 27 chemical workers (group A), and 5 ng/l during the examination of the 19 subjects of the hospital staff (group B). Statistical analysis showed that the alveolar and blood benzene concentrations in the 34 workers exposed to 1.12 microgram/l of benzene differed significantly from those in groups A and B. It was found, moreover, that the alveolar and blood benzene concentrations were higher in the smokers in groups A and B but not in the smokers in the group of 34 chemical workers. The slope of the linear correlation between the alveolar and the instantaneous

  17. 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

    2016-05-01

    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. PMID:26264985

  18. Human benzene metabolism following occupational and environmental exposures.

    Science.gov (United States)

    Rappaport, Stephen M; Kim, Sungkyoon; Lan, Qing; Li, Guilan; Vermeulen, Roel; Waidyanatha, Suramya; Zhang, Luoping; Yin, Songnian; Smith, Martyn T; Rothman, Nathaniel

    2010-03-19

    We previously reported evidence that humans metabolize benzene via two enzymes, including a hitherto unrecognized high-affinity enzyme that was responsible for an estimated 73% of total urinary metabolites [sum of phenol (PH), hydroquinone (HQ), catechol (CA), E,E-muconic acid (MA), and S-phenylmercapturic acid (SPMA)] in nonsmoking females exposed to benzene at sub-saturating (ppb) air concentrations. Here, we used the same Michaelis-Menten-like kinetic models to individually analyze urinary levels of PH, HQ, CA and MA from 263 nonsmoking Chinese women (179 benzene-exposed workers and 84 control workers) with estimated benzene air concentrations ranging from less than 0.001-299 ppm. One model depicted benzene metabolism as a single enzymatic process (1-enzyme model) and the other as two enzymatic processes which competed for access to benzene (2-enzyme model). We evaluated model fits based upon the difference in values of Akaike's Information Criterion (DeltaAIC), and we gauged the weights of evidence favoring the two models based upon the associated Akaike weights and Evidence Ratios. For each metabolite, the 2-enzyme model provided a better fit than the 1-enzyme model with DeltaAIC values decreasing in the order 9.511 for MA, 7.379 for PH, 1.417 for CA, and 0.193 for HQ. The corresponding weights of evidence favoring the 2-enzyme model (Evidence Ratios) were: 116.2:1 for MA, 40.0:1 for PH, 2.0:1 for CA and 1.1:1 for HQ. These results indicate that our earlier findings from models of total metabolites were driven largely by MA, representing the ring-opening pathway, and by PH, representing the ring-hydroxylation pathway. The predicted percentage of benzene metabolized by the putative high-affinity enzyme at an air concentration of 0.001 ppm was 88% based upon urinary MA and was 80% based upon urinary PH. As benzene concentrations increased, the respective percentages of benzene metabolized to MA and PH by the high-affinity enzyme decreased successively to 66 and

  19. Human Benzene Metabolism Following Occupational and Environmental Exposures

    Science.gov (United States)

    Rappaport, Stephen M.; Kim, Sungkyoon; Lan, Qing; Li, Guilan; Vermeulen, Roel; Waidyanatha, Suramya; Zhang, Luoping; Yin, Songnian; Smith, Martyn T.; Rothman, Nathaniel

    2011-01-01

    We previously reported evidence that humans metabolize benzene via two enzymes, including a hitherto unrecognized high-affinity enzyme that was responsible for an estimated 73 percent of total urinary metabolites [sum of phenol (PH), hydroquinone (HQ), catechol (CA), E,E-muconic acid (MA), and S-phenylmercapturic acid (SPMA)] in nonsmoking females exposed to benzene at sub-saturating (ppb) air concentrations. Here, we used the same Michaelis-Menten-like kinetic models to individually analyze urinary levels of PH, HQ, CA and MA from 263 nonsmoking Chinese women (179 benzene-exposed workers and 84 control workers) with estimated benzene air concentrations ranging from less than 0.001 ppm to 299 ppm. One model depicted benzene metabolism as a single enzymatic process (1-enzyme model) and the other as two enzymatic processes which competed for access to benzene (2-enzyme model). We evaluated model fits based upon the difference in values of Akaike’s Information Criterion (ΔAIC), and we gauged the weights of evidence favoring the two models based upon the associated Akaike weights and Evidence Ratios. For each metabolite, the 2-enzyme model provided a better fit than the 1-enzyme model with ΔAIC values decreasing in the order 9.511 for MA, 7.379 for PH, 1.417 for CA, and 0.193 for HQ. The corresponding weights of evidence favoring the 2-enzyme model (Evidence Ratios) were: 116.2:1 for MA, 40.0:1 for PH, 2.0:1 for CA and 1.1:1 for HQ. These results indicate that our earlier findings from models of total metabolites were driven largely by MA, representing the ring-opening pathway, and by PH, representing the ring-hydroxylation pathway. The predicted percentage of benzene metabolized by the putative high-affinity enzyme at an air concentration of 0.001 ppm was 88% based upon urinary MA and was 80% based upon urinary PH. As benzene concentrations increased, the respective percentages of benzene metabolized to MA and PH by the high-affinity enzyme decreased successively

  20. Benzene and lead exposure assessment among occupational bus drivers in Bangkok traffic

    Institute of Scientific and Technical Information of China (English)

    SHING TET LEONG; PREECHA LAORTANAKUL

    2004-01-01

    Four environmental and biological monitoring sites were strategically established to evaluate benzene and lead exposure assessment at various traffic zones of Bangkok Metropolitan Region(BMR). Biological measurement of 48 non air-conditioned, male bus drivers was carried to study the relationship between individual exposure levels and exposure biomarkers. The study group was further subdivided into four age groups( 16-25, 26-35, 36-45 and 46-55 years old) to monitor the age-related exposure effects. A total of 12unexposed persons were deliberately chosen as the control group. Measurement of unmetobolized benzene in blood and analysis of urinary tt-Muconic acid urine and urinary creatinine are recommended as biomarkers of benzene exposure. Measurement of lead in blood and urine is also recommended for the biological monitoring of lead exposure.During the monitoring period, benzene and lead levels at Yaowarat Road was C6H6: 42.46 + 3.88 μg/m3 , Pb: 0.29 + 0.03 μg/m3 and decreased to C6 H6: 33.5 ± 1.35 μg/m3 , Pb: O. 13 + 0.01 μg/m3 at Phahonyothin Road. Significant difference was established between the nonsmoking exposed group and nonsmoking control group for blood benzene concentrations ( P < 0.001, two-tailed, Mann-Whiteney U test). Strong correlations were also found between trans-trans-Muconic acid concentrations in post shift samples and atmospheric benzene concentrations. Similarly, good correlation between all of biomarkers and lead level in air is established from automobile emissions.The analysis revealed that among the occupational population in the urban sites, the driver groups were found to have the highest risk of benzene and lead exposures derived from automobile emission.

  1. Benzene and lead exposure assessment among occupational bus drivers in Bangkok traffic.

    Science.gov (United States)

    Muttamara, S; Leong, Shing Tet; Arayasiri, M

    2004-01-01

    Four environmental and biological monitoring sites were strategically established to evaluate benzene and lead exposure assessment at various traffic zones of Bangkok Metropolitan Region(BMR). Biological measurement of 48 non air-conditioned, male bus drivers was carried to study the relationship between individual exposure levels and exposure biomarkers. The study group was further subdivided into four age groups(16-25, 26-35, 36-45 and 46-55 years old) to monitor the age-related exposure effects. A total of 12 unexposed persons were deliberately chosen as the control group. Measurement of unmetobolized benzene in blood and analysis of urinary tt-Muconic acid urine and urinary creatinine are recommended as biomarkers of benzene exposure. Measurement of lead in blood and urine is also recommended for the biological monitoring of lead exposure. During the monitoring period, benzene and lead levels at Yaowarat Road was C6H6: 42.46 +/- 3.88 microg/m3 , Pb: 0.29 +/- 0.03 microg/m3 and decreased to C6H6: 33.5 +/- 1.35 microg/m3, Pb: 0.13 +/- 0.01 microg/m3 at Phahonyothin Road. Significant difference was established between the nonsmoking exposed group and nonsmoking control group for blood benzene concentrations (P < 0.001, two-tailed, Mann-Whiteney U test). Strong correlations were also found between trans-trans-Muconic acid concentrations in post shift samples and atmospheric benzene concentrations. Similarly, good correlation between all of biomarkers and lead level in air is established from automobile emissions. The analysis revealed that among the occupational population in the urban sites, the driver groups were found to have the highest risk of benzene and lead exposures derived from automobile emission. PMID:14971454

  2. 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

  3. Exposure to methyl tert-butyl ether and benzene among service station attendants and operators.

    Science.gov (United States)

    Hartle, R

    1993-12-01

    Concerns for atmospheric pollution from auto exhaust have led to the blending of "oxygenates" with motor fuels. The most common oxygenate, methyl tert-butyl ether (MTBE) is currently required within several metropolitan areas (Denver and Phoenix) in the range of 12% of the motor fuel. Amendments to the Clean Air Act may expand this requirement to as many as 44 other areas of the United States in the near future. In consideration of the magnitude of potential uncontrolled exposures from its extensive use and a related concern involving the potential influence of MTBE blending on exposures to other constituents of gasoline (particularly benzene), an evaluation of exposures among service station attendants and operators was undertaken at the request, and in cooperation with, the American Petroleum Institute during the latter part of 1990. For application of the survey results to a broad audience, three categories or types of service stations were identified with regard to MTBE use and exposure potential: a) service stations that do not use MTBE or use it only as an octane enhancer, b) service stations with seasonal requirements to use 12-15% MTBE (the Denver, Colorado, and Phoenix, Arizona, metropolitan areas), and c) service stations equipped with stage II (active) vapor recovery systems (several coastal areas, most notably Southern California). At the two sampled service stations that use only minimal amounts of MTBE (less than 1%), only 1 of 32 personal breathing zone (PBZ) samples from attendants was above the analytical limit of detection, reported at 0.16 ppm. The geometric mean concentration of benzene among this same population (n = 32) was 0.04 ppm.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8020445

  4. Brain met-enkephalin immunostaining after subacute and subchronic exposure to benzene

    Energy Technology Data Exchange (ETDEWEB)

    Gandarias, J.M. de; Echevarria, E.; Martinez-Millan, L.; Casis, L. [Univ. of the Basque Country, Bilbao (Spain); Martinez-Garcia, F. [Univ. of Valencia (Spain)

    1994-01-01

    Benzene is used in a wide variety of domestic and occupational activities, and due to its lipophilic nature, it accumulates in lipid-rich tissues like the brain. In this sense, neurotoxic action has long been associated with organic solvent exposure and it has been shown that benzene, injected in a single dose or during a prolongued administration, modifies the content of dopamine, noradrenaline, serotonin and its main metabolite 5-hydroxy indolacetic acid, in several brain regions of the rat, then revealing a stimulating action on brain monoamine synthesis and turnover. However, information concerning neurotoxic action of benzene exposure in vivo on peptidergic neuromodulatory systems is still lacking. Nevertheless, it has been recently described that subacute benzene exposure in rats generates regional changes in brain aminopeptidase activity. These proteolytic enzymes have been widely associated with metabolic control of neuropeptides and it has been suggested that they could play a role in benzene neurotoxic mechanism by hypothetically changing regional neuropeptide levels. This being the case, we focused on analyzing met-enkephalin immunostaining in different brain regions of the rat after subacute and subchronic administration of benzene. 12 refs., 3 figs.

  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. Outdoor NO 2 and benzene exposure in the INMA (Environment and Childhood) Asturias cohort (Spain)

    Science.gov (United States)

    Fernández-Somoano, Ana; Estarlich, Marisa; Ballester, Ferran; Fernández-Patier, Rosalía; Aguirre-Alfaro, Amelia; Herce-Garraleta, Ma Dolores; Tardón, Adonina

    2011-09-01

    Air pollution exposure during pregnancy has been linked to a wide range of negative health effects. NO 2, a traffic pollution marker, and benzene, an industrial pollution indicator, stand out among the types of air pollution linked to these effects. The aim of this work is to show the methodology used to assign exposure levels for both pollutants and preliminary reports in the INMA (Environment and Childhood) Asturias cohort in Spain. This cohort consists of 494 pregnant women and their children, who have been recruited and followed since 2004. Air pollution levels were measured at 67 points by means of passive samplers. The mean NO 2 measured value was 21.2 μg m -3 (range 3.5 μg m -3 to 44.5 μg m -3), and the mean benzene value was 2.72 μg m -3 (range 0.18 μg m -3 to 9.17 μg m -3) at urban sampling points and 0.64 μg m -3 (range 0.04 μg m -3 to 2.62 μg m -3) in rural locations. The Pearson correlation coefficient among pollutants was 0.42. Land Use Regression models were built to predict exposure at the homes of pregnant women. Altitude, road distances and land use were part of the models. The percent of explained variance was 52% for NO 2 and 73% for benzene in the urban zones. No residual autocorrelation was found. Predictions were corrected based on the Air Quality Network of the Principality of Asturias taking into account pregnancy seasonality. Exposure indicators were determined for each term and for the entire pregnancy for each woman. Values for urban locations were higher than those for rural and benzene estimations for 5% of the cohort women were above the European Union annual limit value. Air pollution exposure for the INMA-Asturias cohort clearly depends on the place of residence. In particular, benzene concentrations are remarkably high if an individual lives in an urban and industrial area, which is an issue of management intervention and regulatory concern. Exposure assessment for different pollutants will allow us to evaluate potential

  7. Lack of correlation between environmental or biological indicators of benzene exposure at parts per billion levels and micronuclei induction

    International Nuclear Information System (INIS)

    Despite growing concern for possible carcinogenic effects associated with environmental benzene exposure in the general population, few studies exist at parts per billion (ppb) levels. We investigated the existence of a relationship between airborne/biological measurements of benzene exposure i.e., personal/area sampling and unmodified urinary benzene/trans,trans-muconic acid; t,t-MA) and micronuclei induction cytochalasin B technique) among exposed chemical laboratory workers (n=47) and traffic wardens (n=15). Although urinary t,t-MA (106.9±123.17 μg/Lurine) correlated (R2=0.37) with urinary benzene (0.66±0.99 μg/Lurine), neither biological measurement correlated with environmental benzene exposure (14.04±9.71 μg/m3; 4.39±3.03 ppb), suggesting that, at ppb level (1 ppb=3.2 μg/m3), airborne benzene constitutes a fraction of the total intake. Traffic wardens and laboratory workers had comparable numbers of micronuclei (4.70±2.63 versus .76±3.11; n.s.), similar to levels recorded in the general population. With univariate/multivariate analysis, no association was found between micronuclei induction and air/urinary benzene exposure variables. Notably, among the personal characteristics examined (including age, gender, smoking, drinking, etc.), high body mass index correlated with micronuclei induction while, among females, use of hormonal medication was associated with less micronuclei. Thus the present study provides no evidence that ppb levels of environmental benzene exposure appreciably affect micronuclei incidence against the background of other relevant factors). However, this should not be taken as an argument against efforts aiming to reduce environmental benzene pollution

  8. 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. PMID:23334286

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

    OpenAIRE

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

    1999-01-01

    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 ex...

  10. Maternal Exposure to Ambient Levels of Benzene and Neural Tube Defects among Offspring: Texas, 1999–2004

    OpenAIRE

    Lupo, Philip J.; Symanski, Elaine; Waller, D. Kim; Chan, Wenyaw; Langlois, Peter H; Canfield, Mark A.; Mitchell, Laura E

    2010-01-01

    Background Previous studies have reported positive associations between maternal exposure to air pollutants and several adverse birth outcomes. However, there have been no studies assessing the association between environmental levels of hazardous air pollutants, such as benzene, and neural tube defects (NTDs), a common and serious group of congenital malformations. Objective Our goal was to conduct a case–control study assessing the association between ambient air levels of benzene, toluene,...

  11. Development of a shower exposure model for benzene : background work for potential recommended update to the recently derived drinking water guidelines

    International Nuclear Information System (INIS)

    Chloroform exposure was first identified in showers. Shower exposures were then examined for other volatile substances. This presentation discussed the development of a shower exposure model for benzene and included background work for potential recommended updates to the recently derived drinking water guidelines. Specifically, the presentation addressed the relevance for oil and gas sites and the influence on the drinking water guideline. Issues and limitation with Health Canada's Khrisnan model were identified. The advantages of an alternate model development were also presented. Model structure was examined with particular reference to how model exposures are modelled and the risk associated with taking showers with impacted water. Two general types of models were discussed, notably the simple model used to estimate exposures and the integrated physiologically-based pharmacokinetic model. The relevance of the drinking water guideline revision to the petroleum industry was addressed. It was concluded that future water quality guidelines will likely incorporate shower exposures. tabs., figs.

  12. Meteorological aspects of benzene transport, dispersion and personal exposure in Valdez, Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Murray, D.R.; Ball, R.J. [TRC Environmental Corp., Windsor, CT (United States)

    1994-12-31

    The Valdez Air Health Study (VAHS) was conducted in Valdez, Alaska to determine the personal exposure of the residential population of Valdez to certain volatile organic compounds (VOCs). The VAHS used the EPA`s Total Exposure Assessment Methodology (TEAM) with continuous meteorology, air quality and intense tracer measurements to monitor personal and indoor/outdoor concentrations of VOCs in the community. The Valdez fjord is the site of the Alyeska Marine Terminal, the largest crude oil loading terminal in the United States, with a maximum capacity of 2.2 million barrels per day. The Alyeska Marine Terminal is the transfer point for Prudhoe Bay crude oil from the pipeline to marine tankers. During 1990, the terminal and marine tankers were estimated to emit approximately 450 metric tonnes/year of benzene to the air at an average throughput of 1.8 million barrels/day while benzene emissions from other sources in the basin were estimated to be approximately 3 tonnes/year.

  13. Occupational and ambient exposure to benzene and total hydrocarbons in the downstream petroleum industries and effectiveness of controls for exposure at distribution networks

    International Nuclear Information System (INIS)

    Ambient and occupational exposure to benzene and total hydrocarbon in the downstream petroleum industries were evaluated. Benzene is a minor component in gasoline and is considered to be toxic by the Canadian Environmental Protection Act. It has been classified as a human carcinogen by the International Agency for Research on Cancer. Data was collected from the following sectors of the downstream petroleum industry: refineries, pipelines, marine, bulk terminal, rail car, trucks, service stations, underground storage tanks and site remediation. A comparison of facilities with and without vapour controls was included in this study. A review of the existing literature and previous studies pertaining to benzene exposure revealed a notable lack of Canadian studies on occupational and environmental benzene levels. Traditional methods of benzene and total hydrocarbons (THC) occupational sampling has been long term, providing only time-weighted-average exposure data. Such data does not provide information as to which task of a particular job contributes most to workers' exposure. This data could lead to the development of control measures to reduce environmental benzene and gasoline vapour load. Data in this study was divided into three sections: (1) personal occupational long term samples, i.e.greater than one hour in duration, (2) personal occupational short term samples, i.e. less than one hour in duration, and (3) area and ambient samples, i.e. samples collected within or near the facility. 133 refs., 59 tabs., 6 figs

  14. 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

  15. Exposure to methyl tert-butyl ether, benzene, and total hydrocarbons at the Singapore-Malaysia causeway immigration checkpoint

    Energy Technology Data Exchange (ETDEWEB)

    Tan, C.; Ong, H.Y.; Kok, P.W. [and others

    1996-12-31

    The primary aim of this study was to determine the extent and levels of exposure to volatile organic compounds (VOCs) from automobile emissions in a group of immigration officers at a busy cross-border checkpoint. A majority (80%) of the workers monitored were exposed to benzene at levels between 0.01 and 0.5 ppm, with only 1.2% exceeding the current Occupational Safety and Health Administration occupational exposure limit of 1 ppm. The geometric mean (GM) concentrations of 8-hr time-weighted average exposure were 0.03 ppm, 0.9 ppm, and 2.46 ppm for methyl-tert-butyl ether (MTBE), benzene, and total hydrocarbons (THC), respectively. The highest time-weighted average concentrations measured were 1.05 ppm for MTBE, 2.01 ppm for benzene, and 34 ppm for THC. It was found that motorbikes emitted a more significant amount of pollutants compared with motor cars. On average, officers at the motorcycle booths were exposed to four to five times higher levels of VOCs (GMs of 0.07 ppm, 0.23 ppm, and 4.7 ppm for MTBE, benzene, and THC) than their counterparts at the motor car booths (GMs of 0.01 ppm, 0.05 ppm, and 1.5 ppm). The airborne concentrations of all three pollutants correlated with the flow of vehicle traffic. Close correlations were also noted for the concentrations in ambient air for the three pollutants measured. Benzene and MTBE had a correlation coefficient of 0.97. The overall findings showed that the concentrations of various VOCs were closely related to the traffic density, suggesting that they were from a common source, such as exhaust emissions from the vehicles. The results also indicated that although benzene, MTBE, and THC are known to be volatile, a significant amount could still be detected in the ambient environment, thus contributing to our exposure to these compounds. 4 refs., 6 figs.

  16. The effect of occlusive and unocclusive exposure to xylene and benzene on skin irritation and molecular responses in hairless rats

    Energy Technology Data Exchange (ETDEWEB)

    Chatterjee, A.; Babu, R.J.; Ahaghotu, E.; Singh, M. [Florida A and M University, College of Pharmacy and Pharmaceutical Sciences, Tallahassee, FL (United States)

    2005-05-01

    Aromatic hydrocarbons readily penetrate the skin on dermal exposure, leading to irritation, inflammation and cytotoxicity. The effects of short-term occlusive and long-term unocclusive dermal exposure to benzene and xylene on the skin irritation response (transepidermal water loss (TEWL), skin moisture content and erythema) and cytokine/chemokine expression (interleukin-1{alpha} (IL-1{alpha}), tumor necrosis factor-{alpha} (TNF-{alpha}) and monocyte chemoattractant protein-1 (MCP-1)) were investigated in hairless rats. Occlusive dermal exposure was carried out with 230 {mu}L of the chemicals for 1 h using Hill top chambers. In unocclusive dermal exposure, 15 {mu}L of the chemicals were applied to the skin every 2 h, for 8 h a day, for 4 days. The occlusive dermal exposure revealed a clear difference in the TEWL and erythema response of these chemicals (xylene>benzene) whereas unocclusive exposure revealed similar TEWL and erythema scores for both benzene and xylene. The expression of IL-1{alpha} was elevated 2.5- and 3.8-fold in response to occlusive and unocclusive exposure, respectively, vs control (P<0.01) for both the chemicals (benzene and xylene). Similarly, TNF-{alpha} levels were elevated about 2.4- and 6.0-fold as a result of occlusive and unocclusive exposure, respectively, vs control (P<0.01). These results show that unocclusive exposure induced significantly higher TNF-{alpha} expression than occlusive exposure (P<0.05). The MCP-1 expression in blood was slightly elevated compared with the control group, but this increase was not statistically significant (P>0.05). Similarly, MCP levels in skin were increased approximately 1.7- and 1.8-fold by occlusive and unocclusive exposure, respectively, compared with the control group (P<0.05). Our study demonstrates that the skin irritation profiles of benzene and xylene are similar and unocclusive long-term exposure to small amounts of these chemicals can induce more skin irritation and cytokine response than

  17. Geographical distribution of benzene in air in northwestern Italy and personal exposure.

    OpenAIRE

    Gilli, G.; Scursatone, E; Bono, R.

    1996-01-01

    Benzene is a solvent strictly related to some industrial activities and to automotive emissions. After the reduction in lead content of fuel gasoline, and the consequent decrease in octane number, an increase in benzene and other aromatic hydrocarbons in gasoline occurred. Therefore, an increase in the concentration of these chemicals in the air as primary pollutants and as precursors of photochemical smog could occur in the future. The objectives of this study were to describe the benzene ai...

  18. 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.

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

    Directory of Open Access Journals (Sweden)

    Rongli Sun

    2015-08-01

    Full Text Available 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.

  20. Decreased levels of CXC-chemokines in serum of benzene-exposed workers identified by array-based proteomics

    OpenAIRE

    Vermeulen, Roel; Lan, Qing; Zhang, Luoping; Gunn, Laura; McCarthy, Diane; Woodbury, Ronald L; McGuire, Marielena; Podust, Vladimir N.; Li, Guilan; Chatterjee, Nilanjan; Mu, Ruidong; Yin, Songnian; Rothman, Nathaniel; Smith, Martyn T.

    2005-01-01

    Benzene is an important industrial chemical and environmental contaminant that causes leukemia. To obtain mechanistic insight into benzene's mechanism of action, we examined the impact of benzene on the human serum proteome in a study of exposed healthy shoe-factory workers and unexposed controls. Two sequential studies were performed, each using sera from 10 workers exposed to benzene (overall mean benzene air level >30 ppm) and 10 controls. Serum samples were subjected to anion-exchange fra...

  1. 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.

  2. Benzene exposures caused by traffic in Munich public transportation systems between 1993 and 1997

    Energy Technology Data Exchange (ETDEWEB)

    Roemmelt, H.; Pfaller, A.; Fruhmann, G.; Nowak, D. [Institute and Outpatient Clinic for Occupational and Environmental Medicine, Ludwig-Maximilians-University Munich, Ziemssenstr. 1, D-80336 Munich (Germany)

    1999-10-29

    Volatile aromatics (benzene, toluene, xylenes, the BTX-aromatics) were measured between 1993 and 1997 in buses and trams in Munich center and along main roads during regular rides. The sampling time was between 07.00 and 00.00 h. A total of 631 probes were sampled and centrally analyzed. In the mean of 5 years we found 15.0 {mu}g benzene/m{sup 3}, 50% above the limit of the 23. BImSchV and 107.5 {mu}g BTX aromates/m{sup 3} along the strongly traffic loaded main streets. Splitting up these mean emissions into single years we observed a trend toward a decline of mean immission of all volatile aromatics (benzene from 23.8 {mu}g/m{sup 3} to 7.4 {mu}g/m{sup 3}) and the sum of BTX aromatics (from 147.5 {mu}g/m{sup 3} to 59.4 {mu}g/m{sup 3}). The measured hydrocarbon concentrations in Munich center were consistent with the long range theoretical calculations concerning the decrease of traffic-caused benzene immissions in cities. If the current trends continue, we can expect benzene concentrations to be below 5 {mu}g/m{sup 3} by the year 2001 and below 2.5 {mu}g/m{sup 3} by the year 2008. At these levels, the carcinogenic risk from benzene is probably less significant than the risks to public health from other car exhaust components.

  3. NIOSH (National Institute for Occupational Safety and Health) testimony to DOL (Department of Labor) on OSHA (Occupational Safety and Health Administration) proposed rule for occupational exposure to benzene, by R. Lemen, March 20, 1986

    International Nuclear Information System (INIS)

    The testimony reviewed the history of benzene exposure and the development of recommended exposure limits. Data were reviewed on pharmacokinetics, cytotoxicity, long- and short-term exposures, and skin absorption of benzene. Benzene or its metabolites have been shown to remain in the body for a long period of time following inhalation exposure. Studies in mice revealed exposure-related increases in the frequency of sister chromatid exchanges and micronuclei at all exposure concentrations. Some epidemiological standards relating to the benzene standard were cited. NIOSH recommended that the Permissible Exposure Limit for benzene be reduced to 0.1 ppm as an 8-hour time-weighted average, and that there be a limit on short-term exposures of 1.0ppm for any 15-minute period. These recommendations were made to protect against inhalation of benzene and did not relate to skin absorption. Reports indicated that significant benzene absorption can result among workers exposed to solvents containing about 0.5 percent benzene. It was recommended that steps be taken to eliminate this route of exposure. The use of pressure-demand supplied air respirators with an auxiliary self-contained breathing apparatus or a pressure-demand apparatus was recommended

  4. Monitoring of gas station attendants exposure to benzene, toluene, xylene (BTX) using three-color chromosome painting

    Science.gov (United States)

    2014-01-01

    Background Chronic exposure of BTX (benzene, toluene, xylene) may lead to progressive degeneration of bone marrow, aplastic anemia and/or leukemia. In Brazil there is no self-service fuel in gas stations and attendants fill the fuel themselves. Due to this they are chronically exposed to high concentration of BTX. Occupational exposure to benzene has been associated with increased chromosomal aberrations in peripheral blood lymphocytes. Fluorescence in situ hybridization (FISH) using whole chromosome painting (wcp) probes allows the rapid detection of chromosomal aberration. In the present study three-color wcp probes for chromosomes 1, 2 and 4 were used for monitoring 60 gas station attendants. Results Blood tests were done and interviews were conducted for each worker. For searching for possible associations between the clinical characteristics and the frequency of chromosomal aberrations the workers were divided into two groups (≤ 10 chromosomal abnormalities per 1,000 metaphases and > 10 chromosomal abnormalities per 1,000 metaphases).The studied workers had a low median age (36 year), albeit long period of BTX exposure (median was 16 years). Low prevalence of smoking and moderate consumption of alcoholic beverages were found in this population. The cytogenetic analysis showed 16.6% (10/60) of workers with a high frequency of chromosomal abnormalities (>10 chromosomal abnormalities per 1,000 metaphases). Translocations were the most frequently observed chromosome aberration. The statistical analysis revealed highly significant differences in skin color (p = 0.002) and a weak significant differences in gender (p = 0.052) distribution between the two groups. Conclusion 16.6% of the studied population showed elevated frequencies of chromosomal abnormalities, which is highly likely to be correlated with their exposure to BTX during their work. Therefore, further studies are needed for better characterize the work associated damage of the genome in

  5. JV Task 86 - Identifying the Source of Benzene in Indoor Air Using Different Compound Classes from TO-15 Data

    Energy Technology Data Exchange (ETDEWEB)

    Steven B. Hawthorne

    2007-04-15

    Volatile organic compound (VOC) data that had already been collected using EPA method TO-15 at four different sites under regulatory scrutiny (a school, strip mall, apartment complex, and business/residential neighborhood) were evaluated to determine whether the source of indoor air benzene was outdoor air or vapor intrusion from contaminated soil. Both the use of tracer organics characteristic of different sources and principal component statistical analysis demonstrated that the source of indoor air at virtually all indoor sampling locations was a result of outdoor air, and not contaminated soil in and near the indoor air-sampling locations. These results show that proposed remediation activities to remove benzene-contaminated soil are highly unlikely to reduce indoor air benzene concentrations. A manuscript describing these results is presently being prepared for submission to a peer-reviewed journal.

  6. 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)

  7. Elevated Atmospheric Levels of Benzene and Benzene-Related Compounds from Unconventional Shale Extraction and Processing: Human Health Concern for Residential Communities

    Science.gov (United States)

    Rich, Alisa L.; Orimoloye, Helen T.

    2016-01-01

    BACKGROUND The advancement of natural gas (NG) extraction across the United States (U.S.) raises concern for potential exposure to hazardous air pollutants (HAPs). Benzene, a HAP and a primary chemical of concern due to its classification as a known human carcinogen, is present in petroleum-rich geologic formations and is formed during the combustion of bypass NG. It is a component in solvents, paraffin breakers, and fuels used in NG extraction and processing (E&P). OBJECTIVES The objectives of this study are to confirm the presence of benzene and benzene-related compounds (benzene[s]) in residential areas, where unconventional shale E&P is occurring, and to determine if benzene[s] exists in elevated atmospheric concentrations when compared to national background levels. METHODS Ambient air sampling was conducted in six counties in the Dallas/Fort Worth Metroplex with passive samples collected in evacuated 6-L Summa canisters. Samples were analyzed by gas chromatography/mass spectrometry, with sampling performed at variable distances from the facility fence line. RESULTS Elevated concentrations of benzene[s] in the atmosphere were identified when compared to U.S. Environmental Protection Agency’s Urban Air Toxics Monitoring Program. The 24-hour benzene concentrations ranged from 0.6 parts per billion by volume (ppbv) to 592 ppbv, with 1-hour concentrations from 2.94 ppbv to 2,900.20 ppbv. CONCLUSION Benzene is a known human carcinogen capable of multisystem health effects. Exposure to benzene is correlated with bone marrow and blood-forming organ damage and immune system depression. Sensitive populations (children, pregnant women, elderly, immunocompromised) and occupational workers are at increased risk for adverse health effects from elevated atmospheric levels of benzene[s] in residential areas with unconventional shale E&P. PMID:27199565

  8. The impact of a Bus Rapid Transit system on commuters' exposure to Benzene, CO, PM 2.5 and PM 10 in Mexico City

    Science.gov (United States)

    Wöhrnschimmel, Henry; Zuk, Miriam; Martínez-Villa, Gerardo; Cerón, Julia; Cárdenas, Beatriz; Rojas-Bracho, Leonora; Fernández-Bremauntz, Adrián

    Carbon monoxide (CO), benzene and other volatile organic compounds (VOCs) and suspended particles PM 2.5 and PM 10 were measured inside public transportation vehicles, before and after a new Bus Rapid Transit (BRT) system was implemented in Mexico City in June 2005. The objective was to evaluate the BRT system's impact on commuters' exposure to these air pollutants. The BRT system replaced conventional transport modes along 20 km of Insurgentes Avenue, and features confined corridors and new articulated diesel buses. We assessed the impact of the transportation mode on commuters' exposure using least squares regression models. We also analyzed the chemical composition of VOCs to evaluate the possible origin of these species. The implementation of the BRT system resulted in reductions in commuters' exposure to CO, benzene and PM 2.5 ranging between 20% and 70%. No significant reductions in PM 10 exposure were observed. Lower commuting times further reduced total commuters' exposure. Major sources affecting VOCs inside all transport modes are likely to be related to traffic and to emissions from the use of Liquefied Petroleum Gas. The results suggest that BRT systems could in general be an effective means of reducing human exposure to traffic related air pollutants and associated health impacts.

  9. Sudden Death Due to Cerebral Leukemic Hemorrhage in a 32-Year-Old Woman Who Had a Short-Term Benzene Exposure History.

    Science.gov (United States)

    Wang, Tao; Zhang, Jianhua; Zou, Donghua; Chen, Yijiu

    2016-06-01

    Acute myeloid leukemia (AML), also known as acute myelogenous leukemia, is associated with severe hemorrhagic coagulopathy, which is induced by the drop in red blood cells, platelets, and normal leukocyte and the increase of leukemic cells. The case described in this report was of a 32-year-old woman who unexpectedly and suddenly died because of cerebral hemorrhage caused by undiagnosed AML while hospitalized. Further investigation found that the decedent had been exposed to benzene and its derivatives 6 months before her death. This case suggests that underlying AML should be considered as a possible diagnosis when sudden death occurs with a fatal spontaneous intracerebral hemorrhage, especially if the deceased had occupational chemical exposure to benzene and its derivatives. PMID:27049659

  10. 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.

  11. Current understanding of the mechanism of benzene-induced leukemia in humans: implications for risk assessment

    Science.gov (United States)

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

    2012-01-01

    Benzene causes acute myeloid leukemia and probably other hematological malignancies. As benzene also causes hematotoxicity even in workers exposed to levels below the US permissible occupational exposure limit of 1 part per million, further assessment of the health risks associated with its exposure, particularly at low levels, is needed. Here, we describe the probable mechanism by which benzene induces leukemia involving the targeting of critical genes and pathways through the induction of genetic, chromosomal or epigenetic abnormalities and genomic instability, in a hematopoietic stem cell (HSC); stromal cell dysregulation; apoptosis of HSCs and stromal cells and altered proliferation and differentiation of HSCs. These effects modulated by benzene-induced oxidative stress, aryl hydrocarbon receptor dysregulation and reduced immunosurveillance, lead to the generation of leukemic stem cells and subsequent clonal evolution to leukemia. A mode of action (MOA) approach to the risk assessment of benzene was recently proposed. This approach is limited, however, by the challenges of defining a simple stochastic MOA of benzene-induced leukemogenesis and of identifying relevant and quantifiable parameters associated with potential key events. An alternative risk assessment approach is the application of toxicogenomics and systems biology in human populations, animals and in vitro models of the HSC stem cell niche, exposed to a range of levels of benzene. These approaches will inform our understanding of the mechanisms of benzene toxicity and identify additional biomarkers of exposure, early effect and susceptibility useful for risk assessment. PMID:22166497

  12. Genome-wide functional profiling reveals genes required for tolerance to benzene metabolites in yeast.

    Directory of Open Access Journals (Sweden)

    Matthew North

    Full Text Available 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(PH: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.

  13. Benzene vapor recovery and processing

    International Nuclear Information System (INIS)

    The National Emissions Standards for Hazardous Air Pollutants, or NESHAPs, have provided a powerful motivation for interest in, and attention to, benzene vapor emissions in recent times. Benzene and its related aromatics are volatile organic compounds (VOCs), which marks them for surveillance as potential contributors to air pollution. In addition, benzene is a suspected carcinogen, which applies a special urgency to its control. The regulations governing the control of benzene emissions were issued as Title 40, Code of Federal Regulations, Part 61, subpart Y (Storage Vessels); subpart BB (Transfer Operations); and subpart FF (Waste Operations). These regulations specify very particular emission reduction guidelines for various generating sources. The problem in the hydrocarbon processing industry is to identify significant sources of benzene vapors in plants, and then to collect and process these vapors in an environmentally acceptable manner. This paper discusses various methods for collecting benzene fumes in these facilities

  14. Health risk equations and risk assessment of airborne benzene homologues exposure to drivers and passengers in taxi cabins.

    Science.gov (United States)

    Chen, Xiaokai; Feng, Lili; Luo, Huilong; Cheng, Heming

    2016-03-01

    Interior air environment and health problems of vehicles have attracted increasing attention, and benzene homologues (BHs) including benzene, toluene, ethylbenzene, xylenes, and styrene are primary hazardous gases in vehicular cabins. The BHs impact on the health of passengers and drivers in 38 taxis is assessed, and health risk equations of in-car BHs to different drivers and passengers are induced. The health risk of in-car BHs for male drivers is the highest among all different receptors and is 1.04, 6.67, and 6.94 times more than ones for female drivers, male passengers, and female passengers, respectively. In-car BHs could not lead to the non-cancer health risk to all passengers and drivers as for the maximal value of non-cancer indices is 0.41 and is less than the unacceptable value (1.00) of non-cancer health risk from USEPA. However, in-car BHs lead to cancer health risk to drivers as for the average value of cancer indices is 1.21E-04 which is 1.21 times more than the unacceptable value (1.00E-04) of cancer health risk from USEPA. Finally, for in-car airborne benzene concentration (X, μg/m(3)) to male drivers, female drivers, male passengers, and female passengers, the cancer health risk equations are Y = 1.48E-06X, Y = 1.42E-06X, Y = 2.22E-07X, and Y = 2.13E-07X, respectively, and the non-cancer health risk equations are Y = 1.70E-03X, Y = 1.63E-03X, Y = 2.55E-04X, and Y = 2.45E-04X, respectively. PMID:26538262

  15. Albumin Adducts of Electrophilic Benzene Metabolites in Benzene-Exposed and Control Workers

    OpenAIRE

    Lin, Yu-Sheng; Vermeulen, Roel; Tsai, Chin H.; Waidyanatha, Suramya; Lan, Qing; Rothman, Nathaniel; Smith, Martyn T.; Zhang, Luoping; Shen, Min; Li, Guilan; Yin, Songnian; Kim, Sungkyoon; Rappaport, Stephen M.

    2006-01-01

    Background Metabolism of benzene produces reactive electrophiles, including benzene oxide (BO), 1,4-benzoquinone (1,4-BQ), and 1,2-benzoquinone (1,2-BQ), that are capable of reacting with blood proteins to produce adducts. Objectives The main purpose of this study was to characterize relationships between levels of albumin adducts of these electrophiles in blood and the corresponding benzene exposures in benzene-exposed and control workers, after adjusting for important covariates. Because se...

  16. Effect of hydrolysis on identifying prenatal cannabis exposure

    OpenAIRE

    Gray, Teresa R.; Barnes, Allan J.; Huestis, Marilyn A.

    2010-01-01

    Identification of prenatal cannabis exposure is important due to potential cognitive and behavioral consequences. A two-dimensional gas chromatography–mass spectrometry method for cannabinol, Δ9-tetrahydrocannabinol (THC), 11-hydroxy-THC (11-OH-THC), 8β,11-dihydroxy-THC, and 11-nor-9-carboxy-THC (THCCOOH) quantification in human meconium was developed and validated. Alkaline, enzymatic, and enzyme–alkaline tandem hydrolysis conditions were optimized with THC- and THCCOOH-glucuronide reference...

  17. 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.

  18. Biological monitoring of workers exposed to benzene in the coke oven industry.

    OpenAIRE

    Drummond, L; Luck, R; Afacan, A. S.; Wilson, H K

    1988-01-01

    Workers in the coke oven industry are potentially exposed to low concentrations of benzene. There is a need to establish a well validated biological monitoring procedure for low level benzene exposure. The use of breath and blood benzene and urinary phenol has been explored in conjunction with personal monitoring data. At exposures of about 1 ppm benzene, urinary phenol is of no value as an indicator of uptake/exposure. Benzene in blood was measured by head space gas chromatography but the co...

  19. 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

  20. Small scale spatial gradients of outdoor and indoor benzene in proximity of an integrated steel plant.

    Science.gov (United States)

    Licen, Sabina; Tolloi, Arianna; Briguglio, Sara; Piazzalunga, Andrea; Adami, Gianpiero; Barbieri, Pierluigi

    2016-05-15

    Benzene is known as a human carcinogen, whose annual mean concentration exceeded the EU limit value (5 μg/m(3)) only in very few locations in Europe during 2012. Nevertheless 10% to 12% of the EU-28 urban population was still exposed to benzene concentrations above the WHO reference level of 1.7 μg/m(3). WHO recommended a wise choice of monitoring stations positioning in proximity of "hot spots" to define and assess the representativeness of each site paying attention to micro-scale conditions. In this context benzene and other VOCs of health concern (toluene, ethylbenzene, xylenes) concentrations have been investigated, with weekly passive sampling for one year, both in outdoor and indoor air in inhabited buildings in close proximity (180 m far up to 1100 m) of an integrated steel plant in NE of Italy. Even though the outdoor mean annual benzene concentration was below the EU limit in every site, in the site closest to the works the benzene concentration was above 5 μg/m(3) in 14 weeks. These events were related to a benzene over toluene ratio above one, which is diagnostic for the presence of an industrial source, and to meteorological factors. These information pointed at the identification of the coke ovens of the plant as the dominant outdoor source of benzene. Benzene gradients with the increasing distance from coke ovens have been found for both outdoor and indoor air. Linear models linking outdoor to indoor benzene concentrations have been then identified, allowing to estimate indoor exposure from ambient air benzene data. In the considered period, a narrow area of about 250 m appeared impacted at a higher degree than the other sites both considering outdoor and indoor air. Passive BTEX sampling permits to collect information on both ambient air and daily life settings, allowing to assemble a valuable data support for further environmental cost-benefit analyses. PMID:26930323

  1. 职业接触苯与非霍奇金淋巴瘤关联的Meta分析%The Meta analogy of relationship between benzene exposure and non- Hodgkin lymphoma(NHL)

    Institute of Scientific and Technical Information of China (English)

    王建锋

    2015-01-01

    目的:综合评价接触苯苯与非霍奇金淋巴瘤(non- Hodgkin lymphoma NHL)之间的关联。方法:检索国内外各大类型数据库,获得有关职业接触苯与非霍奇金淋巴瘤(NHL)关系的文献,采用Revman 4.2软件对筛选纳入的相关文献进行Meta分析,并计算合并O R值及其95%可信区间,倒漏斗图法定性评价发表性偏倚。结果:共纳入原始文献11篇,累计病例5916例,对照10346例。经Meta分析得出苯的暴露与非霍奇金淋巴瘤(NHL)发病合并OR值为1.02,95%可信区间为0.92-1.14。结论:苯的暴露与非霍奇金淋巴瘤(NHL)之间不存在相关关系,并不能证明苯暴露是非霍奇金淋巴瘤(NHL)的危险因素之一。%Objective To establish To evaluate the relationship between benzene exposure and non- Hodgkin lymphoma(NHL). Methods Literatures that reported on the associations between benzene exposure and non- Hodgkin lymphoma(NHL) were retrieved by searching international and national databases. Meta-analysis was done by RevMan 4.2 software. The pooled OR values and 95%CI were calculated,and published bias was assessed by funnel plots.Results Totally 11 studies with 5 916 cases and 10 346 controls were enrolled. The analysis showed that the pooled OR of the association between benzene exposure and non- Hodgkin lymphoma(NHL) was 1.02 with the 95%CI of 0.92 to 1.14.Conclusion Benzene exposure may not be associated with non- Hodgkin lymphoma(NHL). benzene exposure may not be a potential risk factor for non- Hodgkin lymphoma(NHL).

  2. Mechanistic considerations in benzene physiological model development

    Energy Technology Data Exchange (ETDEWEB)

    Medinsky, M.A.; Kenyon, E.M.; Seaton, M.J.; Schlosser, P.M. [Chemical Industry Institute of Toxicology, Research Triangle Park, NC (United States)

    1996-12-01

    Benzene, an important industrial solvent, is also present in unleaded gasoline and cigarette smoke. The hematotoxic effects of benzene in humans are well documented and include aplastic anemia, pancytopenia, and acute myelogenous leukemia. However, the risks of leukemia at low exposure concentrations have not been established. A combination of metabolites (hydroquinone and phenol, for example) may be necessary to duplicate the hematotoxic effect of benzene, perhaps due in part to the synergistic effect of phenol on myeloperoxidase-mediated oxidation of hydroquinone to the reactive metabolite benzoquinone. Because benzene and its hydroxylated metabolites (phenol, hydroquinone, and catechol) are substrates for the same cytochrome P450 enzymes, competitive interactions among the metabolites are possible. In vivo data on metabolite formation by mice exposed to various benzene concentrations are consistent with competitive inhibition of phenol oxidation by benzene. In vitro studies of the metabolic oxidation of benzene, phenol, and hydroquinone are consistent with the mechanism of competitive interaction among the metabolites. The dosimetry of benzene and its metabolites in the target tissue, bone marrow, depends on the balance of activation processes such as enzymatic oxidation and deactivation processes such as conjugation and excretion. Phenol, the primary benzene metabolite, can undergo both oxidation and conjugation. Thus the potential exists for competition among various enzymes for phenol. Zonal localization of phase I and phase 11 enzymes in various regions of the liver acinus also impacts this competition. Biologically based dosimetry models that incorporate the important determinants of benzene flux, including interactions with other chemicals, will enable prediction of target tissue doses of benzene and metabolites at low exposure concentrations relevant for humans. 39 refs., 4 figs., 2 tabs.

  3. Interphase cytogenetics of workers exposed to benzene

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, L.; Wang, Yunxia; Venkatesh, P. [Univ. of California, Berkeley, CA (United States)] [and others

    1996-12-01

    Fluorescence in situ hybridization (FISH) is a powerful new technique that allows numerical chromosome aberrations (aneuploidy) to be detected in interphase cells. In previous studies, FISH has been used to demonstrate that the benzene metabolites hydroquinone and 1,2,4-benzenetriol induce aneuploidy of chromosomes 7 and 9 in cultures of human cells. In the present study, we used an interphase FISH procedure to perform cytogenetic analyses on the blood cells of 43 workers exposed to benzene (median=31 ppm, 8-hr time-weighted average) and 44 matched controls from Shanghai, China. High benzene exposure (>31 ppm, n=22) increased the hyperdiploid frequency of chromosome 9 (p<0.01), but lower exposure (<31 ppm, n=21) did not. Trisomy 9 was the major form of benzene-induced hyperdiploidy. The level of hyperdiploidy in exposed workers correlated with their urinary phenol level (r= 0.58, p < 0.0001), a measure of internal benzene close. A significant correlation was also found between hyperdiploicly and decreased absolute lymphocyte count, an indicator of benzene hematotoxicity, in the exposed group (r=-0.44, p=0.003) but not in controls (r=-0.09, P=0.58). These results show that high benzene exposure induces aneuploidy of chromosome 9 in nondiseased individuals, with trisomy being the most prevalent form. They further highlight the usefulness of interphase cytogenetics and FISH for the rapid and sensitive detection of aneuploidy in exposed human populations. 35 refs., 3 figs., 2 tabs.

  4. Sources of toxicity and exposure information for identifying chemicals of high concern to children

    International Nuclear Information System (INIS)

    Due to the large number of chemicals in commerce without adequate toxicity characterization data, coupled with an ineffective federal policy for chemical management in the United States, many states are grappling with the challenge to identify toxic chemicals that may pose a risk to human health and the environment. Specific populations (e.g., children, elderly) are particularly sensitive to these toxic chemicals. In 2008, the Children's Safe Product Act (CSPA) was passed in Washington State. The CSPA included specific requirements to identify High Priority Chemicals (HPCs) and Chemicals of High Concern to Children (CHCCs). To implement this legislation, a methodology was developed to identify HPCs from authoritative scientific and regulatory sources on the basis of toxicity criteria. Another set of chemicals of concern was then identified from authoritative sources, based on their potential exposure to children. Exposure potential was evaluated by identifying chemicals detected in biomonitoring studies (i.e., human tissues), as well as those present in residential exposure media (e.g., indoor air, house dust, drinking water, consumer products). Accordingly, CHCCs were defined as HPCs that also appear in biomonitoring studies or relevant exposure media. For chemicals with unique Chemical Abstracts Service (CAS) numbers, we identified 2044 HPCs and 2219 chemicals with potential exposure to children, resulting in 476 CHCCs. The process of chemical identification is dynamic, so that chemicals may be added or subtracted as new information becomes available. Although beyond the scope of this paper, the 476 CHCCs will be prioritized in a more detailed assessment, based on the strength and weight of evidence of toxicity and exposure data. Our approach was developed to be flexible which allows the addition or removal of specific sources of toxicity or exposure information, as well as transparent to allow clear identification of inputs. Although the methodology was

  5. Establishment of biological limit value of urinary S-phenylmercapturic acid for occupational exposure to benzene%职业接触苯尿中苯巯基尿酸生物限值研究

    Institute of Scientific and Technical Information of China (English)

    梅勇; 宋世震; 陈斯琦; 叶玉杰; 叶方立

    2009-01-01

    Objective To establish the biological exposure limit values of urinary S-phenylmercap-turic acid (SPMA) for assessing occupational exposure to benzene. Methods Study participants were selected from 55 workers of benzene exposures below 32.5 mg/m~3. The concentration of personal exposure to benzene was measured by gas chromatography and sampled with personal sampler. The urine samples were collected at the end of work shift and individual internal exposure level was evaluated by determination of SPMA in urine by HPLC/MS method. Comparison of external and internal exposure was assessed by the relative internal expo-sure(RIE) index. Results The benzene exposure level ranged from 0.71 to 32.17 mg/m~3 (geometric mean 6.98 mg/m~3, median 7.50 mg/m~3). The urinary SPMA at the end of the work shift were significantly correlated with benzene exposure, Y (μg/g Cr)=-8.625 + 18.367X (mg/m~3), r=0.8035, (P<0.01). According to the occupational exposure limit for benzene in China and calculation of regression equation, the expected value of urinary SPMA was 101.58 μg/g Cr. Mean level of biotransformation of per mg/m~3 benzene to urinary SPMA was 18.23 μg/g Cr and the metabolic efficiencies of benzene transformation to urinary SPMA decreased with benzene exposure in-creased. Conclusion Based on abroad documents and data, biological limit value for occupational exposure to benzene in China is recommended as follows: 100 μg/g Cr (47 μmol/mol Cr) for SPMA in the urine at the end of shift.%目的 研制我国职业接触苯工人尿中苯巯基尿酸(SPMA)的生物限值.方法 在苯作业车间选择空气中苯浓度在32.5 mg/m~3以下接苯工人55人,应用个体采样器采集空气样品,用气相色谱法检测作业者个体苯接触水平,同时采集当日工人班后尿,应用高压液相色谱/质谱法(HPLC/MS)测定尿中SPMA含量以评价苯接触者的内暴露水平,内外暴露水平的比较用相对内暴露指数(RIE)加以评定.结果 接苯工人工作

  6. 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.

  7. 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,...

  8. 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...

  9. 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

  10. An Evaluation of a Teat Dip with Dodecyl Benzene Sulfonic Acid in Preventing Bovine Mammary Gland Infection from Experimental Exposure to Streptococcus agalactiae and Staphylococcus aureus

    OpenAIRE

    Barnum, D A; Johnson, R. E.; Brooks, B W

    1982-01-01

    The effectiveness of a teat dip with dodecyl benzene sulfonic acid (1.94%) for the prevention of intramammary infections was determined in cows experimentally challenged with Streptococcus agalactiae and Staphylococcus aureus. The infection rates with Streptococcus agalactiae and Staphylococcus aureus were 62.5% and 75% in undipped quarters, 12.5% and 21.5% in dipped quarters with a reduction rate of 80% and 71% respectively. The significance of some findings in relation to mastitis control a...

  11. [Update on benzene: from industrial toxicant to environmental carcinogen].

    Science.gov (United States)

    Manno, Maurizio

    2013-01-01

    Benzene, an industrial chemical myelotoxic at high doses in workers, is now an almost ubiquitous pollutant. It is also a no-threshold genotoxic carcinogen causing acute leukemia and other lymphoaematological tumours. Although its mechanism of action has not been fully clarified, benzene toxicity and carcinogenicity depend on metabolic activation. Polymorphism of activating and detoxifying enzymes (CYP, GST, NQO1) may be critical, therefore, in modulating individual susceptibility to benzene. Further uncertainty factors in assessing low level benzene exposure are the limited sensitivity and specificity of most exposure biomarkers, the frequent coexposure to other volatile organic chemicals (VOC), and the presence of non occupational sources of exposure, such as cigarette smoke and veicular traffic. The aim of this presentation is to introduce the main current critical issues in the risk assessment and the biological monitoring of occupational exposure to benzene at low doses. PMID:24303704

  12. Benzene from Traffic

    DEFF Research Database (Denmark)

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

    The measurements of benzene showed very clear decreasing trends in the air concentrations and the emissions since 1994. At the same time the measurements of CO and NOx also showed a decreasing trend, but not so strong as for benzene. The general decreasing trend is explained by the increasing...... 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...

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

    International Nuclear Information System (INIS)

    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.

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

    OpenAIRE

    Carlo de Olim; Denis Bégin; Louis-Philippe Boulet; André Cartier; Michel Gérin; Catherine Lemière

    2015-01-01

    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.OBJECTIVE: The broad aim of the present study was to evaluate the contribution of an expert assessment perform...

  15. Identifying constituents to participate in a project to control pesticide exposure in children of farmworkers.

    Science.gov (United States)

    Thompson, B; Coronado, G; Puschel, K; Allen, E

    2001-01-01

    Farmers in Washington State use pesticides to control harmful pests that might interfere with the quality of their products. Farmworkers, who are primarily responsible for thinning, harvesting, and other agricultural work, are often exposed to these pesticides and take home pesticide residues on their clothing, shoes, and skin, potentially exposing children in the household to pesticides. We designed a project to reduce children's exposure by using a community organization model. To better understand the community views regarding pesticide exposure, we conducted a qualitative community analysis. Two methods of data gathering were used to collect information. Individual interviews were conducted with some respondents, and small group discussions were held with others. Analysis indicated wide disparity among involved groups in their views on pesticides; however, a number of themes common to the majority of the constituents were identified and discussed with a community planning group. Because of the contention around pesticides, the group recommended every constituent participate in decision making. The group noted it was important to emphasize that the research project could provide scientific information on pesticide exposure to everyone in the Lower Yakima Valley. Our study demonstrates both the widely varying views of different constituents around the issue of pesticide exposure and common themes that can form the basis for collaboration and consensus on approaching the issue. PMID:11427394

  16. 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...

  17. 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 <1.5% and a total of 16 clusters, involving 39/131 (29.8%), were identified. Younger age and heterosexual exposure were independently related with clustering in the inferred 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. PMID:26990771

  18. Mapping radioactivity in groundwater to identify elevated exposure in remote and rural communities

    International Nuclear Information System (INIS)

    A survey of radioactivity in groundwater (110 sites) was conducted as a precursor to providing a baseline of radiation exposure in rural and remote communities in Queensland, Australia, that may be impacted upon by exposure pathways associated with the supply, treatment, use and wastewater treatment of the resource. Radionuclides in groundwater, including 238U, 226Ra, 222Rn, 228Ra, 224Ra and 40K were measured and found to contain activity concentration levels of up to 0.71 BqL-1, 0.96 BqL-1, 108 BqL-1, 2.8 BqL-1, 0.11 BqL-1 and 0.19 BqL-1 respectively. Activity concentration results were classified by aquifer lithology, showing correlation between increased radium isotope concentration and basic volcanic host rock. The groundwater survey and mapping results were further assessed using an investigation assessment tool to identify seven remote or rural communities that may require additional radiation dose assessment beyond that attributed to ingestion of potable water. - Research highlights: → We studied the concentration of naturally occurring radioactivity in groundwater in Queensland, Australia. → Groundwater radioactivity concentrations were classified by aquifer type, location and magnitude. → Radioactivity concentration in groundwater was used to develop a tool to determine the potential for elevated radiation exposure to rural and remote communities, based on a case study of a reference site. → Of 110 groundwater bores tested, seven were assessed as requiring further community dose assessment.

  19. Comparing plasma and X-ray exposure and identifying vulnerable cell parts

    Science.gov (United States)

    Graham, Bill

    2012-10-01

    Here two issues in plasma medicine that are being addressed in a collaboration between the Centre of Plasma Physics and the School of Pharmacy at Queen's University Belfast and the Plasma Institute at York University UK will be discussed. Recent measurements of the interaction of plasmas created directly in DMEM cell medium and MDAMB-231, a human breast cancer cell line, showed evidence of reduced cell viability and of DNA damage. The same set of experiments were undertaken but with X-ray exposure. A correlation of the dependence on plasma exposure time and X-ray dose was observed which might point the way to dose definition in plasma medicine. We have also been working to identify the cell parts most vulnerable to plasma exposure. In this study a 10 kHz atmospheric pressure non-thermal plasma jet, operating in He/0.5%O2 and characterized to determine the behavior of many of the plasma species, was incident onto the surface of media containing either bacterial strains, in their planktonic and biofilm forms, or isolated bacterial plasmid DNA. The results of measurements to look for changes in plasmid structural conformation, rates of single and double strand breaks, the catalytic activity of certain bacterial enzymes, the peroxidation of lipid content of the bacterial cells, the leakage of ATP and Scanning Electron Microscope (SEM) images will be discussed.

  20. Benzene release. Status report

    International Nuclear Information System (INIS)

    Scoping benzene release measurements were conducted on 4 wt percent KTPB 'DEMO' formulation slurry using a round, flat bottomed 100-mL flask containing 75 mL slurry. The slurry was agitated with a magnetic stirrer bar to keep the surface refreshed without creating a vortex. Benzene release measurements were made by purging the vapor space at a constant rate and analyzing for benzene by gas chromatography with automatic data acquisition. Some of the data have been rounded or simplified in view of the scoping nature of this study

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

    International Nuclear Information System (INIS)

    A study was conducted to determine the exposure of workers; exposure limits, and the delegation of responsibilities and special measures of compensation, protection and security. Likewise, monitoring, personal exposure assessments, externally and internally, are analyzed

  2. Facts about Benzene

    Science.gov (United States)

    ... Lab Info Chemical Emergencies A–Z Abrin Adamsite Ammonia Arsenic Arsine Barium Benzene Brevetoxin Bromine BZ Carbon ... used to make some types of lubricants, rubbers, dyes, detergents, drugs, and pesticides. How you could be ...

  3. Benzene Monitor System report

    Energy Technology Data Exchange (ETDEWEB)

    Livingston, R.R.

    1992-10-12

    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/PR{close_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 & 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).

  4. Source investigation of personal particulates in relation to identify major routes of exposure among urban residentials

    Science.gov (United States)

    Gadkari, Neelima M.; Pervez, Shamsh

    Multiple 24-h average outdoor, indoor and personal respirable particulate matter (RPM) measurements were made in different urban residential colonies to determine major routes of personal exposure. The study area was Bhilai-Durg, District Durg, Chhattisgarh, India. About 100 residentials from each of two selected colonies have been surveyed for consent to participate in the study and for preparation of time-activity diary. On the basis of their time-activity diary, residentials have been categorized into three types: type-A, purely residential; type-B, residents who go out, and type-C, residence who go into work, specially in industrial area. A total of 28 adult participants (14 males and 14 females; mean age 40±15, range 21-61 years) were selected and monitored longitudinally during the summer (15 March-15 June) of 2004. Participants' residential indoor RPM level and also local ambient outdoor RPM levels were measured,and these are done simultaneous with personal monitoring. Residential indoor and ambient outdoors RPM monitoring sessions were throughout the year to obtain infiltration factor more precisely. To compare RPM levels with Indian National Ambient Air Quality Standards (NAAQS) of PM 10, simultaneous measurements of PM 10 were also done with the course of ambient outdoor RPM monitoring. RPM levels in indoors were higher compared to ambient outdoors. The annual average ratio RPM/PM 10 was found to vary significantly among residential sites due to variation in surroundings. Source contribution estimates (SCE) of personal exposure to RPM in selected 12 residences (six from each colony) have been investigated using chemical mass balance model CMB8. Ambient outdoors, residential indoors, soils and road-traffic borne RPM were identified as main routes and principal sources of personal RPM. Results of model output have shown that residential indoors and soil-borne RPM are the major routes of personal exposure.

  5. Design of a TL personal dosimeter identifiable PA exposure and development of its dose evaluation algorithm

    International Nuclear Information System (INIS)

    A single-dosimeter worn on the anterior surface of body of a worker was found to provide significant underestimation of dose to the worker when radiation comes from behind of human body. Recently, several researchers suggested that this kind of underestimation can be corrected to a certain extent by using an extra dosimeter on the back. But these multiple dosimetry also have the disadvantages like overestimation or cost burden. In this study, a single dosimeter introducing asymmetric filters enabled to identify PA exposure was designed and its dose evaluation algorithm for AP-PA mixed radiation field was established. A prototype TL personal dosimeter was designed and manufactured by Monte-Carlo simulation and experiment. It was assured that TL personal dosimeter and dose evaluation algorithm developed in this study showed excellent performance by fulfilling simplified performance test and comparing commercial dosimeters. This algorithm were applicable to penetrating radiation had the effective energy more than 100 keV. Besides, the dosimeter and algorithm in this study were possible to be applied to near PA exposure

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

    International Nuclear Information System (INIS)

    Lactating adult female mice treated with a single dose of 880 mg/kg i.p. [14C]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 blood

  7. Phase II metabolism of benzene.

    OpenAIRE

    Schrenk, D.; Orzechowski, A.; Schwarz, L R; Snyder, R.; Burchell, B; Ingelman-Sundberg, M; K. W. DE BOCK

    1996-01-01

    The hepatic metabolism of benzene is thought to be a prerequisite for its bony marrow toxicity. However, the complete pattern of benzene metabolites formed in the liver and their role in bone marrow toxicity are not fully understood. Therefore, benzene metabolism was studied in isolated rodent hepatocytes. Rat hepatocytes released benzene-1,2-dihydrodiol, hydroquinone (HQ), catechol (CT), phenol (PH), trans-trans-muconic acid, and a number of phase II metabolites such as PH sulfate and PH glu...

  8. 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.

  9. Economical benzene emission reduction

    International Nuclear Information System (INIS)

    Benzene has been classified as a toxic compound under the Canadian Environmental Protection Act. This has prompted the Alberta Energy and Utilities Board (AEUB) to introduce specific reporting and monitoring guidelines for the oil and gas industry regarding excessive benzene emissions. Glycol dehydration units have been determined to be the major single source of benzene emissions causing air and soil pollution. DualTank Corp. has designed a condensation and storage tank unit to enhance emission reduction, odour elimination and liquid recovery from dehydration units. Their newly designed combined tank unit consists of a large, uninsulated surface area for cooling, and an excessive internal volume for increased retention time. The first prototype was installed in December 1998 at an Enerplus Resources Site. The system provides excellent benzene emission reduction and the elimination of odours and visual plumes. Effective January 1, 1999, the petroleum and natural gas industry must either clean up excessive emissions voluntarily or face government imposed regulations, facility shutdowns and/or fines. 1 fig

  10. Genotoxic and histotoxic effects of air pollutants at a benzene station on albino rats

    Directory of Open Access Journals (Sweden)

    Mohamed Abousalem

    2014-02-01

    Conclusions: The findings of the present study indicated that benzene exposure may lead to toxic effects including, genotoxicities and histotoxicities. In order to minimize the predicted toxic effect of occupational exposure to benzene the strict protective measures should be put in consideration. [Int J Basic Clin Pharmacol 2014; 3(1.000: 144-150

  11. 11. USING BIOMARKERS TO IMPROVE BENZENE RISK ASSESSMENT AND FIND THE CAUSES OF LEUKAEMIA

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@Benzene is an established cause of leukemia at high doses, but the risk it poses at exposures of ≤1ppm in air is diffcult to quantify. Molecular biomarkers may improve the accuracy of this risk assessment. We have therefore attempted to develop and validate biomarkers of exposure, early effect and susceptibility to benzene. We have shown

  12. 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

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

    International Nuclear Information System (INIS)

    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

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. 40 CFR 721.1580 - Disubstituted benzene ether, polymer with substituted phenol (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Disubstituted benzene ether, polymer... Significant New Uses for Specific Chemical Substances § 721.1580 Disubstituted benzene ether, polymer with... chemical substance generically identified as disubstituted benzene ether, polymer with substituted...

  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. 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.

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

    International Nuclear Information System (INIS)

    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)

  2. 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. PMID:25935538

  3. Modulation of mast cell and basophil functions by benzene metabolites.

    Science.gov (United States)

    Triggiani, Massimo; Loffredo, Stefania; Granata, Francescopaolo; Staiano, Rosaria I; Marone, Gianni

    2011-11-01

    Benzene is a carcinogenic compound used in industrial manufacturing and a common environmental pollutant mostly derived from vehicle emissions and cigarette smoke. Benzene exposure is associated with a variety of clinical conditions ranging from hematologic diseases to chronic lung disorders. Beside its direct toxicity, benzene exerts multiple effects after being converted to reactive metabolites such as hydroquinone and benzoquinone. Mast cells and basophils are primary effector cells involved in the development of respiratory allergies such as rhinitis and bronchial asthma and they play an important role in innate immunity. Benzene and its metabolites can influence mast cell and basophil responses either directly or by interfering with other cells, such as T cells, macrophages and monocytes, which are functionally connected to mast cells and basophils. Hydroquinone and benzoquinone inhibit the release of preformed mediators, leukotriene synthesis and cytokine production in human basophils stimulated by IgE- and non IgE-mediated agonists. Furthermore, these metabolites reduce IgE-mediated degranulation of mast cells and the development of allergic lung inflammation in rats. Both in vitro and in vivo studies indicate that benzene metabolites alter biochemical and functional activities of other immunocompetent cells and may impair immune responses in the lung. These inhibitory effects of benzene metabolites are primarily mediated by interference with early transduction signals such as PI3 kinase. Together, currently available studies indicate that benzene metabolites interfere by multiple mechanisms with the role of basophils and mast cells in innate immunity and in chronic inflammation in the lung. PMID:22103854

  4. 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.

  5. Benzene hemoglobin adducts in mice and rats: Characterization of formation and physiological modeling

    International Nuclear Information System (INIS)

    Benzene is a myelotoxin and a human leukemogen. Humans are exposed to this compound, both occupationally and environmentally. This study was conducted to determine whether formation of benzene-derived adducts with blood hemoglobin (Hb) can be used as a biomarker of exposure to benzene. B6C3F1 mice and F344/N rats were given 0.1 to 10,000 mumol [14C]benzene/kg body wt, orally. Twenty-four hours later, animals were euthanized, and globin was isolated from blood samples. The globin was analyzed by liquid scintillation spectrometry for the presence of [14C]benzene-derived adducts. Hb adduct formation was linear with respect to dose for amounts of up to 500 mumol [14C]benzene/kg body wt, for both rodent species. Within this linear dose-response range, mice formed adducts from [14C]benzene approximately 3.5 times less efficiently [0.022 +/- 0.010 (pmol adducts/mg globin)/(mumol/kg body wt dose)] than did rats [0.076 +/- 0.014 (pmol adducts)/(mumol/kg body wt dose)]. Benzene-derived Hb adducts also accumulated linearly when mice and rats were given up to three daily doses of 500 mumol [14C]benzene/kg body wt. These data were used to develop a physiological model for benzene-derived Hb adduct formation. Both first-order and saturable pathways for adduct formation were incorporated. The results showed that the model simulated the levels of Hb adducts in both mice and rats after oral exposures to benzene and predicted the levels of Hb adducts present after inhalation exposure. These studies suggest that Hb adducts might be useful biomarkers for human exposures to benzene

  6. Identifying constituents to participate in a project to control pesticide exposure in children of farmworkers.

    OpenAIRE

    Thompson, B.; Coronado, G.; Puschel, K.; Allen, E

    2001-01-01

    Farmers in Washington State use pesticides to control harmful pests that might interfere with the quality of their products. Farmworkers, who are primarily responsible for thinning, harvesting, and other agricultural work, are often exposed to these pesticides and take home pesticide residues on their clothing, shoes, and skin, potentially exposing children in the household to pesticides. We designed a project to reduce children's exposure by using a community organization model. To better un...

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

    International Nuclear Information System (INIS)

    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

  8. RNA-Seq identifies key reproductive gene expression alterations in response to cadmium exposure.

    Science.gov (United States)

    Hu, Hanyang; Lu, Xing; Cen, Xiang; Chen, Xiaohua; Li, Feng; Zhong, Shan

    2014-01-01

    Cadmium is a common toxicant that is detrimental to many tissues. Although a number of transcriptional signatures have been revealed in different tissues after cadmium treatment, the genes involved in the cadmium caused male reproductive toxicity, and the underlying molecular mechanism remains unclear. Here we observed that the mice treated with different amount of cadmium in their rodent chow for six months exhibited reduced serum testosterone. We then performed RNA-seq to comprehensively investigate the mice testicular transcriptome to further elucidate the mechanism. Our results showed that hundreds of genes expression altered significantly in response to cadmium treatment. In particular, we found several transcriptional signatures closely related to the biological processes of regulation of hormone, gamete generation, and sexual reproduction, respectively. The expression of several testosterone synthetic key enzyme genes, such as Star, Cyp11a1, and Cyp17a1, were inhibited by the cadmium exposure. For better understanding of the cadmium-mediated transcriptional regulatory mechanism of the genes, we computationally analyzed the transcription factors binding sites and the mircoRNAs targets of the differentially expressed genes. Our findings suggest that the reproductive toxicity by cadmium exposure is implicated in multiple layers of deregulation of several biological processes and transcriptional regulation in mice. PMID:24982889

  9. RNA-Seq Identifies Key Reproductive Gene Expression Alterations in Response to Cadmium Exposure

    Directory of Open Access Journals (Sweden)

    Hanyang Hu

    2014-01-01

    Full Text Available Cadmium is a common toxicant that is detrimental to many tissues. Although a number of transcriptional signatures have been revealed in different tissues after cadmium treatment, the genes involved in the cadmium caused male reproductive toxicity, and the underlying molecular mechanism remains unclear. Here we observed that the mice treated with different amount of cadmium in their rodent chow for six months exhibited reduced serum testosterone. We then performed RNA-seq to comprehensively investigate the mice testicular transcriptome to further elucidate the mechanism. Our results showed that hundreds of genes expression altered significantly in response to cadmium treatment. In particular, we found several transcriptional signatures closely related to the biological processes of regulation of hormone, gamete generation, and sexual reproduction, respectively. The expression of several testosterone synthetic key enzyme genes, such as Star, Cyp11a1, and Cyp17a1, were inhibited by the cadmium exposure. For better understanding of the cadmium-mediated transcriptional regulatory mechanism of the genes, we computationally analyzed the transcription factors binding sites and the mircoRNAs targets of the differentially expressed genes. Our findings suggest that the reproductive toxicity by cadmium exposure is implicated in multiple layers of deregulation of several biological processes and transcriptional regulation in mice.

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

    OpenAIRE

    M. Rahiminejad; S.Gh. Mirsattari; A. Bahrami; B. Akbari

    2006-01-01

    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-contro...

  11. 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...

  12. 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,...

  13. 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...

  14. 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 thre

  15. The combined biological effects of low dose radiation, carbon monoxide, benzene and noise on rats

    International Nuclear Information System (INIS)

    Objective: To investigate the combined biological effects of low dose radiation, carbon monoxide,benzene and noise on rats. Methods: Sixteen male SD rats were randomly divided into experiment group and control group. The experiment group was exposed to carbon monoxide, benzene, low dose radiation and noise daily, the control group was in common environment. Peripheral blood, organ index, and marrow DNA content were detected. Two-dimensional electrophoresis (2-DE) was performed on serum protein analysis. Differential expressed proteins were identified by a matrix assisted laser desorption/ionization time of flight mass spectrometry (MAIDI-TOF-MS). Results: Compared to control group, the liver index, spleen index, thymus index, leukocytes, platelets count, and marrow DNA content of the experiment group were decreased significantly (t=2.732, 4.141, 3.053, 2.211, 2.668, 11.592, P<0.05). 12 altered proteins were detected and through identification, 3 proteins were definite in terms of serum amyloid A-4 protein (SAA4), trichoplein keratin filament-binding protein (TCHP) and tubulin alpha-4A chain (TUBA4A). Conclusions: The hematopoietic system and immune system of rats are damaged significantly with the changes of several serum protein expressions by the combined exposure of low dose radiation, carbon monoxide, benzene and noise. This study may provide new information for the mechanism of the combination effects. (authors)

  16. Mechanistically identified suitable biomarkers of exposure, effect, and susceptibility for silicosis and coal-worker's pneumoconiosis: a comprehensive review.

    Science.gov (United States)

    Gulumian, M; Borm, P J A; Vallyathan, V; Castranova, V; Donaldson, K; Nelson, G; Murray, J

    2006-01-01

    Clinical detection of silicosis is currently dependent on radiological and lung function abnormalities, both late manifestations of disease. Markers of prediction and early detection of pneumoconiosis are imperative for the implementation of timely intervention strategies. Understanding the underlying mechanisms of the etiology of coal workers pneumoconiosis (CWP) and silicosis was essential in proposing numerous biomarkers that have been evaluated to assess effects following exposure to crystalline silica and/or coal mine dust. Human validation studies have substantiated some of these proposed biomarkers and argued in favor of their use as biomarkers for crystalline silica- and CWP-induced pneumoconiosis. A number of "ideal" biological markers of effect were identified, namely, Clara cell protein-16 (CC16) (serum), tumor necrosis factor-alpha (TNF-alpha) (monocyte release), interleukin-8 (IL-8) (monocyte release), reactive oxygen species (ROS) measurement by chemiluminescence (neutrophil release), 8-isoprostanes (serum), total antioxidant levels measured by total equivalent antioxidant capacity (TEAC), glutathione, glutathione peroxidase activity, glutathione S-transferase activity, and platelet-derived growth factor (PDGF) (serum). TNF-alpha polymorphism (blood cellular DNA) was identified as a biomarker of susceptibility. Further studies are planned to test the validity and feasibility of these biomarkers to detect either high exposure to crystalline silica and early silicosis or susceptibility to silicosis in gold miners in South Africa. PMID:16990219

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

    Science.gov (United States)

    Rappaport, Stephen M; Kim, Sungkyoon; Thomas, Reuben; Johnson, Brent A; Bois, Frederic Y; Kupper, Lawrence L

    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 American Petroleum Institute to fund a study by Price et al. to reanalyze the original data. Although their formal 'reanalysis' reproduced Kim's finding of enhanced DSM at sub-p.p.m. 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

  18. Linking exposure to environmental pollutants with biological effects

    DEFF Research Database (Denmark)

    Sørensen, Mette; Autrup, Herman; Møller, Peter;

    2003-01-01

    Exposure to ambient air pollution has been associated with cancer. Ambient air contains a complex mixture of toxics, including particulate matter (PM) and benzene. Carcinogenic effects of PM may relate both to the content of PAH and to oxidative DNA damage generated by transition metals, benzene......, metabolism and inflammation. By means of personal monitoring and biomarkers of internal dose, biologically effective dose and susceptibility, it should be possible to characterize individual exposure and identify air pollution sources with relevant biological effects. In a series of studies, individual...... setting, 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...

  19. 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.

  20. Products of the Benzene + O(3P) Reaction

    Energy Technology Data Exchange (ETDEWEB)

    Taatjes, Craig A.; Osborn, David L.; Selby, Talitha M.; Meloni, Giovanni; Trevitt, Adam J.; Epifanovsky, Evgeny; Krylov, Anna I.; Sirjean, Baptiste; Dames, Enoch; Wang, Hai

    2009-12-21

    The gas-phase reaction of benzene with O(3P) is of considerable interest for modeling of aromatic oxidation, and also because there exist fundamental questions concerning the prominence of intersystem crossing in the reaction. While its overall rate constant has been studied extensively, there are still significant uncertainties in the product distribution. The reaction proceeds mainly through the addition of the O atom to benzene, forming an initial triplet diradical adduct, which can either dissociate to form the phenoxy radical and H atom, or undergo intersystem crossing onto a singlet surface, followed by a multiplicity of internal isomerizations, leading to several possible reaction products. In this work, we examined the product branching ratios of the reaction between benzene and O(3P) over the temperature range of 300 to 1000 K and pressure range of 1 to 10 Torr. The reactions were initiated by pulsed-laser photolysis of NO2 in the presence of benzene and helium buffer in a slow-flow reactor, and reaction products were identified by using the multiplexed chemical kinetics photoionization mass spectrometer operating at the Advanced Light Source (ALS) of Lawrence Berkeley National Laboratory. Phenol and phenoxy radical were detected and quantified. Cyclopentadiene and cyclopentadienyl radical were directly identified for the first time. Finally, ab initio calculations and master equation/RRKM modeling were used to reproduce the experimental branching ratios, yielding pressure-dependent rate expressions for the reaction channels, including phenoxy + H, phenol, cyclopentadiene + CO, which are proposed for kinetic modeling of benzene oxidation.

  1. Marine environmental protection: An application of the nanometer photo catalyst method on decomposition of benzene.

    Science.gov (United States)

    Lin, Mu-Chien; Kao, Jui-Chung

    2016-04-15

    Bioremediation is currently extensively employed in the elimination of coastal oil pollution, but it is not very effective as the process takes several months to degrade oil. Among the components of oil, benzene degradation is difficult due to its stable characteristics. This paper describes an experimental study on the decomposition of benzene by titanium dioxide (TiO2) nanometer photocatalysis. The photocatalyst is illuminated with 360-nm ultraviolet light for generation of peroxide ions. This results in complete decomposition of benzene, thus yielding CO2 and H2O. In this study, a nonwoven fabric is coated with the photocatalyst and benzene. Using the Double-Shot Py-GC system on the residual component, complete decomposition of the benzene was verified by 4h of exposure to ultraviolet light. The method proposed in this study can be directly applied to elimination of marine oil pollution. Further studies will be conducted on coastal oil pollution in situ. PMID:26922359

  2. Canada-wide standard for benzene phase 2

    International Nuclear Information System (INIS)

    On the basis of available data, benzene is classified as carcinogenic to humans, and it led to the establishment, pursuant to the 1998 Canada-wide Accord on Environmental Harmonization of the Canadian Council of Ministers of the Environment (CCME) and its Canada-wide Environmental Standards Sub-Agreement, of the Canada-Wide Standard (CWS) for benzene. It is generally considered that any level of exposure carries some probability of harmful effects. A balancing act between achieving the best health and environmental protection possible and feasibility and costs associated with the reduction of emissions contributing to elevated levels of benzene in the air was performed for the development of this CWS. In June 2000, the Ministers of the Environment agreed to a phased approach to benzene reduction. To this effect, the Canada-Wide Standard for Benzene Phase 1 was ratified. By the end of 2000, a 30 per cent reduction in total benzene emissions form 1995 emission inventory levels was expected, according to Phase 1. The measures initiated during Phase 1 will continue beyond the time frame, and Phase 2 calls for a follow-through on those measures. Best management practices and jurisdictional regulations that will minimize emissions are recognized as part of Phase 2. Joint action in conjunction with other air issue programs should lead to additional reductions. Specifically, Phase 2 calls for an additional reduction of 6 kilotonnes in benzene emissions for existing facilities by the end of 2010. The minimization of benzene emissions through the application of best available pollution prevention and control techniques is contained for new and expanding facilities. The implementation of the CWS comprises the follow-up of existing initiatives resulting from the application of Phase 1 and the promotion and application of best management practices for new and expanding facilities, the determination and tracking of ancillary emission reductions of benzene realized as a result of

  3. Mapping the Racial Inequality in Place: Using Youth Perceptions to Identify Unequal Exposure to Neighborhood Environmental Hazards.

    Science.gov (United States)

    Teixeira, Samantha; Zuberi, Anita

    2016-01-01

    Black youth are more likely than white youth to grow up in poor, segregated neighborhoods. This racial inequality in the neighborhood environments of black youth increases their contact with hazardous neighborhood environmental features including violence and toxic exposures that contribute to racial inequality in youth health and well-being. While the concept of neighborhood effects has been studied at length by social scientists, this work has not been as frequently situated within an environmental justice (EJ) paradigm. The present study used youth perceptions gained from in-depth interviews with youth from one Pittsburgh, Pennsylvania neighborhood to identify neighborhood environmental health hazards. We then mapped these youth-identified features to examine how they are spatially and racially distributed across the city. Our results suggest that the intersection of race and poverty, neighborhood disorder, housing abandonment, and crime were salient issues for youth. The maps show support for the youths' assertions that the environments of black and white individuals across the city of Pittsburgh differ in noteworthy ways. This multi-lens, mixed-method analysis was designed to challenge some of the assumptions we make about addressing environmental inequality using youths' own opinions on the issue to drive our inquiry. PMID:27571086

  4. 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.

  5. 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. PMID:17119257

  6. Species differences in the metabolism of benzene.

    OpenAIRE

    Henderson, R F

    1996-01-01

    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 th...

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

    OpenAIRE

    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 B6C3F1 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. ...

  8. 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...

  9. 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.

  10. Genotoxic and histotoxic effects of air pollutants at a benzene station on albino rats

    OpenAIRE

    Mohamed Abousalem; Amer Elgerwi; Abdel Baset El-Mashad

    2014-01-01

    Background: This study was designed to explore the hazardous effects of occupational exposure to air pollutants arising from benzene stations. Methods: A total of 48 albino rats were divided into three groups each of sixteen animals. Groups-I and II were kept at a benzene station for 60 and 120 days, respectively; while group-III was kept as a control under normal laboratory conditions. At the end of the experiment, animals were sacrificed and bone marrow samples were taken to investigate ...

  11. 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...

  12. Double photoionization of halogenated benzene

    International Nuclear Information System (INIS)

    We have experimentally investigated the double-photoionization process in C6BrF5 using monochromatized synchrotron radiation. We compare our results with previously published data for partially deuterated benzene (C6H3D3) over a wide range of photon energies from threshold to 270 eV. A broad resonance in the ratio of doubly to singly charged parent ions at about 65 eV appears shifted in energy compared to benzene data. This shift is due to the difference in the bond lengths in two molecules. A simple model can explain the shape of this resonance. At higher photon energies, we observe another broad resonance that can be explained as a second harmonic of the first resonance

  13. Double photoionization of halogenated benzene

    Energy Technology Data Exchange (ETDEWEB)

    AlKhaldi, Mashaal Q. [Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstr. 36, D-10623 Berlin (Germany); Wehlitz, Ralf, E-mail: rwehlitz@gmail.com [Synchrotron Radiation Center, University of Wisconsin–Madison, Stoughton, Wisconsin 53589 (United States)

    2016-01-28

    We have experimentally investigated the double-photoionization process in C{sub 6}BrF{sub 5} using monochromatized synchrotron radiation. We compare our results with previously published data for partially deuterated benzene (C{sub 6}H{sub 3}D{sub 3}) over a wide range of photon energies from threshold to 270 eV. A broad resonance in the ratio of doubly to singly charged parent ions at about 65 eV appears shifted in energy compared to benzene data. This shift is due to the difference in the bond lengths in two molecules. A simple model can explain the shape of this resonance. At higher photon energies, we observe another broad resonance that can be explained as a second harmonic of the first resonance.

  14. Slow Neutron Scattering by Benzene

    International Nuclear Information System (INIS)

    We have calculated the scattering of slow neutrons by the benzene molecule. The calculations are carried out within the framework of the time dependent formalism of Zemach and Glauber. Detailed account is taken of the effects of the molecular vibrations on the neutron scattering. Among the results explicitly calculated are the slow neutron total scattering cross-section as a function of energy and the energy angular distribution of singly scattered sections. (author)

  15. Annoyance Caused by Noise and Air Pollution during Pregnancy: Associated Factors and Correlation with Outdoor NO2 and Benzene Estimations.

    OpenAIRE

    Ana Fernández-Somoano; Sabrina Llop; Inmaculada Aguilera; Ibon Tamayo-Uria; María Dolores Martínez; Maria Foraster; Ferran Ballester; Adonina Tardón

    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 (...

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

    International Nuclear Information System (INIS)

    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+ 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)

  17. Modulation of phase-II enzyme activities in benzene treated ovariectomized rats.

    Science.gov (United States)

    Verma, Yeshvandra; Rana, S V S

    2011-05-01

    The aim of the study was to determine the influence of ovariectomy on phase II enzymes viz. glutathione-S-transferase (GST), glutathione peroxidase (GPX) and catalase (CAT) in liver and kidney of female rats treated with benzene. The results showed the significant decrease of the GST and GPX activity in benzene treated rats after ovariectomy. However progesterone supplementation stimulated the activity of GST and GPX in liver and kidney of benzene treated non ovariectomized and ovariectomized rats. Progesterone supplementation to benzene treated ovariectomized rats helps to gain in CAT activity. Our results on DNA damage using single cell gel electrophoresis also confirmed our findings on antioxidant enzymes. The results showed that lack of protective progesterone against benzene toxicity is reflected in alterations in antioxidant enzyme activities. However progesterone therapy to benzene treated ovariectomized rats results in activating the antioxidant defence system. Since female workers are engaged in industrial sector, these results are important from occupational health point of view. Benzene exposure affects their reproductive health. Nevertheless, it could be modulated by suitable hormonal therapy. PMID:21787707

  18. Electrochemical behaviour of benzene on platinum electrodes

    OpenAIRE

    Montilla Jiménez, Francisco; Huerta Arráez, Francisco; Morallón Núñez, Emilia; Vázquez Picó, José Luis

    1999-01-01

    The adsorption and oxidation of benzene in acidic media on platinum electrodes (polycrystalline and single-crystal electrodes) have been studied by cyclic voltammetry and in-situ Fourier transform infrared spectroscopy. The oxidation characteristics of benzene depend on the surface structure of the platinum electrode used. In all platinum electrodes studied, the main reduction product of benzene is cyclohexane, and the oxidation products detected by infrared spectroscopy have been CO2 and ben...

  19. Natural Biological Attenuation of Benzene in Groundwater

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Benzene has been found in subsurface unsaturated soil and groundwater beneath a petro-chemical plant. Although the groundwater contained several mg/L of benzene in the area immediately beneath the source, benzene was not detected in monitoring wells approximately 800m down stream. All kinds of physical processes such as adsorption and advection/dispersion are considered to account for the observed attenuation. The results indicated that the attenuation was primarily due to natural biological processes occurring within the aquifer. The evidence for the natural bioremediation of benzene from the groundwater included: (1) analysis of groundwater chemistry, (2) laboratory studies demonstrating benzene biodegradation in aquifer samples, and (3) computer simulations examining benzene transport. Laboratory experiments indicated that for conditions similar to those in the plume, the aerobic degradation of benzene by the naturally occurring microorganisms in the polluted groundwater samples was quite rapid with a half-life time of from 5 to 15 days. In situ analyses indicated the level of dissolved oxygen in the groundwater was over 2mg/L. Thus, oxygen should not limit the biodegradation. In fact, the benzene was also shown to degrade under anaerobic conditions. The results from the modeling simulations indicate that biodegradation is the dominant process influencing attenuation of the benzene.

  20. Effect of benzene on the cerebellar structure and behavioral characteristics in rats

    Institute of Scientific and Technical Information of China (English)

    Ali; Rafati; Mahboobeh; Erfanizadeh; Ali; Noorafshan; Saied; Karbalay-Doust

    2015-01-01

    Objective: To investigate the effects of benzene on rat’s cerebellum structure and behavioral characteristics, including anxiety and motor impairment.Methods: Twenty rats were randomly allocated into two groups orally receiving distilled water and benzene(200 mg/kg/day). A total of 10 rats were used at the beginning of benzene exposure. Two rats died during benzene treatment and 8 rats remained for evaluation of the behavioral test and finally 6 rats underwent histological assessment. At the end of the 4th week, motor function and anxiety were evaluated in rotarod test and elevated plus maze, respectively. Besides, the cerebellum was dissected for structural assessment using stereological methods.Results: Performance of the benzene-treated rats in fixed and accelerating speed rotarod was impaired and their riding time(endurance) was lower compared to the control group(P = 0.02). The benzene-treated rats also spent less time in the open arms and had fewer entrances to the open arms in comparison to the control group, indicating anxiety(P = 0.01). The total volume of the cerebellar hemisphere, its cortex, intracerebellar nuclei, total number of the Purkinje, Bergmann, Golgi, granule, neurons and glial cells of the molecular layer, and neurons and glial cells of the intracerebellar nuclei were reduced by 34%-76% in the benzene-treated rats in comparison to the distilled water group(P = 0.003). The most cell loss was seen in Bergmann glia. Conclusions: The structure of cerebellum altered after benzene treatment. In addition, motor impairment and anxiety could be seen in benzene-treated rats.

  1. Effect of benzene on the cerebellar structure and behavioral characteristics in rats

    Institute of Scientific and Technical Information of China (English)

    Ali Rafati; Mahboobeh Erfanizadeh; Ali Noorafshan; Saied Karbalay-Doust

    2015-01-01

    Objective:To investigate the effects of benzene on rat’s cerebellum structure and behavioral characteristics, including anxiety and motor impairment. Methods:Twenty rats were randomly allocated into two groups orally receiving distilled water and benzene (200 mg/kg/day). A total of 10 rats were used at the beginning of benzene exposure. Two rats died during benzene treatment and 8 rats remained for evaluation of the behavioral test and finally 6 rats underwent histological assessment. At the end of the 4th week, motor function and anxiety were evaluated in rotarod test and elevated plus maze, respectively. Besides, the cerebellum was dissected for structural assessment using stereological methods. Results:Performance of the benzene-treated rats in fixed and accelerating speed rotarod was impaired and their riding time (endurance) was lower compared to the control group (P=0.02). The benzene-treated rats also spent less time in the open arms and had fewer entrances to the open arms in comparison to the control group, indicating anxiety (P=0.01). The total volume of the cerebellar hemisphere, its cortex, intracerebellar nuclei, total number of the Purkinje, Bergmann, Golgi, granule, neurons and glial cells of the molecular layer, and neurons and glial cells of the intracerebellar nuclei were reduced by 34%-76%in the benzene-treated rats in comparison to the distilled water group (P=0.003). The most cell loss was seen in Bergmann glia. Conclusions:The structure of cerebellum altered after benzene treatment. In addition, motor impairment and anxiety could be seen in benzene-treated rats.

  2. 76 FR 38175 - Notice of Release of the Exposure Draft Revisions to Identifying and Reporting Earmarked Funds...

    Science.gov (United States)

    2011-06-29

    ... Funds: Amending Statement of Federal Financial Accounting Standards 27 AGENCY: Federal Accounting... Financial Accounting Standards 27. The Exposure Draft is available on the FASAB home page http://www.fasab... From the Federal Register Online via the Government Publishing Office FEDERAL ACCOUNTING...

  3. Upstream petroleum industry glycol dehydrator benzene emissions status report

    International Nuclear Information System (INIS)

    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

  4. 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.

  5. 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.

  6. 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 chemist dealing with GC-MS in confirmation and quantification of benzene in environmental samples with health risk exposure assessment. PMID:15782977

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

    Science.gov (United States)

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

    2015-04-01

    As a highly toxic heavy metal, the pollution and exposure risks of lead are of widespread concern for human health. However, the collection of blood samples for use as an indicator of lead pollution is not always feasible in most cohort or longitudinal studies, especially those involving children health. To evaluate the potential use of urinary lead as an indicator of exposure levels and source apportionment, accompanying with environmental media samples, lead concentrations and isotopic measurements (expressed as (207)Pb/(206)Pb, (208)Pb/(206)Pb and (204)Pb/(206)Pb) were investigated and compared between blood and urine from children living in the vicinities of a typical coking plant and lead-acid battery factory. The results showed urinary lead might not be a preferable proxy for estimating blood lead levels. Fortunately, urinary lead isotopic measurements could be used as an alternative for identifying the sources of children's lead exposure, which coincided well with the blood lead isotope ratio analysis. PMID:25617855

  8. 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...

  9. 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...

  10. 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....

  11. 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...

  12. Bio sensing Benzene in the refinery

    International Nuclear Information System (INIS)

    A biosensor based on Pseudomonas putida cells was utilized for Benzene analysis in air of an oil refinery. Biosensoristic approach was compared to gaschromatografic essay. We also developed bio sensing Benzene genetically modified Escherichia coli and tested them with refinery samples. Microbial biosensor were useful to determine air pollution.

  13. A Factor Analysis of Global GABAergic Gene Expression in Human Brain Identifies Specificity in Response to Chronic Alcohol and Cocaine Exposure

    OpenAIRE

    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...

  14. Molecular dynamics simulation of benzene

    Science.gov (United States)

    Trumpakaj, Zygmunt; Linde, Bogumił B. J.

    2016-03-01

    Intermolecular potentials and a few models of intermolecular interaction in liquid benzene are tested by Molecular Dynamics (MD) simulations. The repulsive part of the Lennard-Jones 12-6 (LJ 12-6) potential is too hard, which yields incorrect results. The exp-6 potential with a too hard repulsive term is also often used. Therefore, we took an expa-6 potential with a small Gaussian correction plus electrostatic interactions. This allows to modify the curvature of the potential. The MD simulations are carried out in the temperature range 280-352 K under normal pressure and at experimental density. The Rayleigh scattering of depolarized light is used for comparison. The results of MD simulations are comparable with the experimental values.

  15. Comparison of hematological alterations and markers of B-cell activation in workers exposed to benzene, formaldehyde and trichloroethylene.

    Science.gov (United States)

    Bassig, Bryan A; Zhang, Luoping; Vermeulen, Roel; Tang, Xiaojiang; Li, Guilan; Hu, Wei; Guo, Weihong; Purdue, Mark P; Yin, Songnian; Rappaport, Stephen M; Shen, Min; Ji, Zhiying; Qiu, Chuangyi; Ge, Yichen; Hosgood, H Dean; Reiss, Boris; Wu, Banghua; Xie, Yuxuan; Li, Laiyu; Yue, Fei; Freeman, Laura E Beane; Blair, Aaron; Hayes, Richard B; Huang, Hanlin; Smith, Martyn T; Rothman, Nathaniel; Lan, Qing

    2016-07-01

    Benzene, formaldehyde (FA) and trichloroethylene (TCE) are ubiquitous chemicals in workplaces and the general environment. Benzene is an established myeloid leukemogen and probable lymphomagen. FA is classified as a myeloid leukemogen but has not been associated with non-Hodgkin lymphoma (NHL), whereas TCE has been associated with NHL but not myeloid leukemia. Epidemiologic associations between FA and myeloid leukemia, and between benzene, TCE and NHL are, however, still debated. Previously, we showed that these chemicals are associated with hematotoxicity in cross-sectional studies of factory workers in China, which included extensive personal monitoring and biological sample collection. Here, we compare and contrast patterns of hematotoxicity, monosomy 7 in myeloid progenitor cells (MPCs), and B-cell activation biomarkers across these studies to further evaluate possible mechanisms of action and consistency of effects with observed hematologic cancer risks. Workers exposed to benzene or FA, but not TCE, showed declines in cell types derived from MPCs, including granulocytes and platelets. Alterations in lymphoid cell types, including B cells and CD4+ T cells, and B-cell activation markers were apparent in workers exposed to benzene or TCE. Given that alterations in myeloid and lymphoid cell types are associated with hematological malignancies, our data provide biologic insight into the epidemiological evidence linking benzene and FA exposure with myeloid leukemia risk, and TCE and benzene exposure with NHL risk. PMID:27207665

  16. 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

    2016-05-01

    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.

  17. On the mechanistic differences of benzene-induced leukemogenesis between wild type and p53 knockout mice

    International Nuclear Information System (INIS)

    Leukemia induction by benzene inhalation was first reported by Le Noire in 1887, described multiple cases of leukemia among Parisian cobblers. However, experimental induction of leukemia by benzene exposure was not succeeded for a hundred years, until Snyder et al. and our group reported it nearly 20 years ago. Nevertheless, the mechanistic background of benzene-induced leukemia was still an enigma until recently a benzene-induced peculiar cell kinetics of the stem/progenitor cells has been elucidated by our study, demonstrated a marked repeated oscillatory decrease in peripheral blood and bone marrow (BM) cellularity during and after benzene exposure, which epigenetically preceded and developed the leukemia more than a year later. We utilized the BUUV (bromodeoxyuridine + UV exposure) method to study stem/progenitor cell kinetics during and/or after benzene exposure. Using these methods, we were able to measure the labeling rate, cycling fraction of clonogenic progenitor cells, and other cell cycle parameters. The cycling fraction of stem/progenitor cells was found not to turn into an active hematopoiesis but to remain low during benzene inhalation and further we found evidence that the cycling fraction depression may be mediated in part by a slowing of stem/progenitor cell cycling perse by up-regulation of p21. The benzene induced leukemogenicity between mice carrying wild-type p53 and mice lacking p53 seem to differ from one another. In the case of p53 knockout mouse, DNA damage such as weak mutagenicity and or chromosomal damages are retained, and those damages participated in the induction of a consequent activation of proto-oncogenes and the like, which led cells to further neoplastic changes. In contrast, in the case of wild type mice, a dramatic oscillational change in the cell cycle of the stem cell compartment seems to be an important factor for mice carrying the p53 gene. (author)

  18. 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...... types (p < 0.01). 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...

  19. Benzene metabolism by human liver microsomes in relation to cytochrome P450 2E1 activity.

    Science.gov (United States)

    Seaton, M J; Schlosser, P M; Bond, J A; Medinsky, M A

    1994-09-01

    . Validation of this system in vivo should lead to more accurate assessment of the risk of benzene's toxicity following low-level exposure. PMID:7923572

  20. 46 CFR Appendix C to Subpart C to... - Medical Surveillance Guidelines for Benzene

    Science.gov (United States)

    2010-10-01

    ... principal effects of benzene exposure addressed in 46 CFR part 197, subpart C, appendix A, are pathological... specified in 46 CFR 197.560 is designed to observe, on a regular basis, blood indices for early signs of... required in 46 CFR 197.560. There are special provisions for medical tests in the event of...

  1. IRIS Toxicological Review of Benzene (Noncancer Effects) (1998 External Review Draft)

    Science.gov (United States)

    Benzene is a widely used as an industrial solvent, an intermediate in chemical synthesis of commercial products, and a component of gasoline. The potential for human exposure via inhalation, dermal, and oral routes is great under environmental and occupational situations. The U.S...

  2. 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 emissio

  3. Excited state of protonated benzene and toluene

    International Nuclear Information System (INIS)

    We present photo-fragmentation electronic spectra of the simplest protonated aromatic molecules, protonated benzene and toluene, recorded under medium resolution conditions and compared with the photo-fragmentation spectrum of protonated pyridine. Despite the resolution and cold temperature achieved in the experiment, the electronic spectra of protonated benzene and toluene are structure-less, thus intrinsically broadened. This is in agreement with the large geometrical changes and the fast dynamic toward internal conversion predicted by ab initio calculations for protonated benzene [Rode et al., J. Phys. Chem. A 113, 5865–5873 (2009)

  4. Towards a visual recognition threshold: new instrument shows humans identify animals with only 1ms of visual exposure.

    Science.gov (United States)

    Thurgood, Clementine; Whitfield, T W Allan; Patterson, John

    2011-09-01

    The human visual system is very adept at extracting categorical information from complex scenes with only the briefest of exposure. Here we show that information from visual scenes can be processed to the level of identification with formally unattainable, ultra-brief (1ms) presentations. This brief presentation time is afforded by a new instrument, the light-emitting diode (LED) tachistoscope, in which a liquid crystal display (LCD) is illuminated externally by a brief LED flash after LCD steady-state is reached, such that image onset and offset timing can be precisely controlled. Photographs of animals were presented with or without backgrounds for 1ms and 10ms. The results indicate that visual recognition of objects benefits from presenting them in isolation rather than with a background at smaller (1ms) durations. In both conditions, however, animals could be recognised at 1ms at least 83% of the time, possibly due to iconic memory and top-down, feedback mechanisms. PMID:21787801

  5. The role of geographical ecological studies in identifying diseases linked to UVB exposure and/or vitamin D.

    Science.gov (United States)

    Grant, William B

    2016-01-01

    Using a variety of approaches, researchers have studied the health effects of solar ultraviolet (UV) radiation exposure and vitamin D. This review compares the contributions from geographical ecological studies with those of observational studies and clinical trials. Health outcomes discussed were based on the author's knowledge and include anaphylaxis/food allergy, atopic dermatitis and eczema, attention deficit hyperactivity disorder, autism, back pain, cancer, dental caries, diabetes mellitus type 1, hypertension, inflammatory bowel disease, lupus, mononucleosis, multiple sclerosis, Parkinson disease, pneumonia, rheumatoid arthritis, and sepsis. Important interactions have taken place between study types; sometimes ecological studies were the first to report an inverse correlation between solar UVB doses and health outcomes such as for cancer, leading to both observational studies and clinical trials. In other cases, ecological studies added to the knowledge base. Many ecological studies include other important risk-modifying factors, thereby minimizing the chance of reporting the wrong link. Laboratory studies of mechanisms generally support the role of vitamin D in the outcomes discussed. Indications exist that for some outcomes, UVB effects may be independent of vitamin D. This paper discusses the concept of the ecological fallacy, noting that it applies to all epidemiological studies. PMID:27195055

  6. Four component catalysis for the hydroalkylation of benzene to cyclohexyl benzene

    Energy Technology Data Exchange (ETDEWEB)

    Fahy, J.; Trimm, D.L. [School of Chemical Engineering and Industrial Chemistry, University of New South Wales, NSW 2052 Sydney (Australia); Cookson, D.J. [BHP Melbourne Research Laboratories, Vic. Melbourne (Australia)

    2001-04-13

    Patent claims that benzene can be hydroalkylated to form cyclohexyl benzene - a potential diesel fuel - over a four component catalyst have been verified, and the role of the individual components has been explored. The hydrogenation of benzene over nickel on zeolite 13X produced reasonably high (ca. 30%) yields of cyclohexane, but the product distribution favoured cyclohexyl benzene in the presence of rare earth ions. The addition of small (ca. 1%) of platinum produced good yields and selectivities to cyclohexyl benzene at ca. 450K, a performance which was matched only at ca. 670K in the absence of platinum. Temperature programmed studies showed that Pt promoted the low temperature reduction of the catalyst to produce better performance. The acidic 13X molecular sieve promoted alkylation, but acidity was not the only factor involved. Rare earth additions were suggested to induce electron transfer to the nickel, weakening adsorption of benzene and promoting hydroalkylation rather than hydrogenation.

  7. 46 CFR 197.565 - Notifying personnel of benzene hazards.

    Science.gov (United States)

    2010-10-01

    ... appendices A and B of this subpart or a MSDS on benzene meeting the requirements of 29 CFR 1910.1200(g) is... 46 Shipping 7 2010-10-01 2010-10-01 false Notifying personnel of benzene hazards. 197.565 Section... AND HEALTH STANDARDS GENERAL PROVISIONS Benzene § 197.565 Notifying personnel of benzene hazards....

  8. Recommended sublimation pressure and enthalpy of benzene

    International Nuclear Information System (INIS)

    Highlights: • Sublimation pressures of benzene were measured. • Benzene thermodynamic properties in the state of ideal gas were calculated. • Recommended sublimation pressure and enthalpy of benzene were developed. -- Abstract: Recommended vapor pressures of solid benzene (CAS Registry Number: 71-43-2) which are consistent with thermodynamically related crystalline and ideal-gas heat capacities as well as with properties of the liquid phase at the triple point temperature (vapor pressure, enthalpy of vaporization) were established. The recommended data were developed by a multi-property simultaneous correlation of vapor pressures and related thermal data. Vapor pressures measured in this work using the static method in the temperature range from 233 K to 260 K, covering pressure range from 99 Pa to 1230 Pa, were included in the simultaneous correlation. The enthalpy of sublimation was established with uncertainty significantly lower than the previously recommended values

  9. Pill characterization data streams for reducing exposure to inadequately identified anti-malarial medication in developing countries

    Directory of Open Access Journals (Sweden)

    Crandall Ian

    2010-07-01

    Full Text Available Abstract Background A large fraction of anti-malaria medicines (and indeed many other medicines classes used in developing countries are inadequately identified. Framing this problem as one of misidentification rather than the more common framing of criminal misrepresentation leads to new solutions sets not currently being considered. Method That reframing led to consideration and analysis of 4 new problems that informed design of a digital platform technology for delivering a distributed medicine characterization system: 1 problematic interests associated with a focus on preventing counterfeiting, 2 the complexity of the many ways that medicines can deviate from expected identities, 3 the challenge of choosing amongst a diversity of attribute characterization technologies, and 4 the need for a flexible and distributed data aggregation mechanism. Results Analysis of those new problems confirmed an initial insight that a previously described digital technology for tracking malaria tests results in infrastructure limited regions could be adapted for characterizing pill attributes. Feasibility is illustrated by describing how the platform design can be implemented using open-source software and commodity computational and communication technology readily available and supportable in developing countries. Discussion A system of this type would allow users to answer several questions. Is this medicine what it is supposed to be? Can it be used to treat locally encountered malaria? What has been the experience of others who have used pills having the same identity? Ubiquitous access to global digital telecommunication infrastructure allows the system to generate data streams from these distributed medicine characterization transactions that can be used to map global patterns of use of specifically identified medicines. This can provide feedback necessary to guide efforts to reduce the burden of malaria.

  10. Degradation of Benzene by Using a Silent-Packed Bed Hybrid Discharge Plasma Reactor

    Institute of Scientific and Technical Information of China (English)

    姜楠; 鲁娜; 李杰; 吴彦

    2012-01-01

    In this work, a novel gas phase silent-packed bed hybrid discharge plasma reactor has been proposed, and its ability to control a simulative gas stream containing 240 ppm benzene is experimentally investigated. In order to optimize the geometry of the reactor, the benzene conversion rate and energy yield (EY) were compared for various inner electrode diameters and quartz tube shapes and sizes. In addition, benzene removal efficiency in different discharge regions was qualitatively analyzed and the gas parameter (space velocity) was systematically studied. It has been found that silent-packed bed hybrid discharge plasma reactor can effectively decompose benzene. Benzene removal proved to achieve an optimum value of 60% with a characteristic energy density of 255 J/L in this paper with a 6 mm bolt high-voltage electrode and a 13 mm quartz tube. The optimal space velocity was 188.1 h^-1, which resulted in moderate energy yield and removal efficiency. Reaction by-products such as hydroquinone, heptanoic acid, 4-nitrocatechol, phenol and 4-phenoxy-phenol were identified by mean of GC-MS. In addition, based on these organic by-products, a benzene destruction pathway was proposed.

  11. Degradation of Benzene by Using a Silent-Packed Bed Hybrid Discharge Plasma Reactor

    Science.gov (United States)

    Jiang, Nan; Lu, Na; Li, Jie; Wu, Yan

    2012-02-01

    In this work, a novel gas phase silent-packed bed hybrid discharge plasma reactor has been proposed, and its ability to control a simulative gas stream containing 240 ppm benzene is experimentally investigated. In order to optimize the geometry of the reactor, the benzene conversion rate and energy yield (EY) were compared for various inner electrode diameters and quartz tube shapes and sizes. In addition, benzene removal efficiency in different discharge regions was qualitatively analyzed and the gas parameter (space velocity) was systematically studied. It has been found that silent-packed bed hybrid discharge plasma reactor can effectively decompose benzene. Benzene removal proved to achieve an optimum value of 60% with a characteristic energy density of 255 J/L in this paper with a 6 mm bolt high-voltage electrode and a 13 mm quartz tube. The optimal space velocity was 188.1 h-1, which resulted in moderate energy yield and removal efficiency. Reaction by-products such as hydroquinone, heptanoic acid, 4-nitrocatechol, phenol and 4-phenoxy-phenol were identified by mean of GC-MS. In addition, based on these organic by-products, a benzene destruction pathway was proposed.

  12. Canada-wide standard for benzene phase 1 : Progress report 2001

    International Nuclear Information System (INIS)

    In June 2000, the Canadian Council of Ministers of the Environment (CCME) ratified the Canada-Wide Standard (CWS) for Benzene Phase 1. Benzene is classified as a carcinogen to humans and any level of exposure is generally considered to carry some probability of harmful effects. The Ministers committed to reducing national benzene emissions by 30 per cent between 1995 and 2000. This report presents the progress thus far and describes how the Alberta Government has focused on effecting emission reductions in the natural gas sector, dehydrators, petroleum refineries and in chemical manufacturing plants. Their initiatives led to a 66 per cent decrease in benzene emissions by 1999. In addition, overall emissions in the province were reduced by 50 per cent from industry and mobile sources. The measures initiated during Phase 1 will continue beyond the time frame, and Phase 2, not yet ratified, will call for a follow-through on those measures. Phase 2 recognizes best management practices and jurisdictional regulations that will minimize emissions. Specifically, Phase 2 calls for an additional reduction of 6 kilotonnes in benzene emissions for existing facilities by the end of 2010. The minimization of benzene emissions through the application of best available pollution prevention and control techniques is contained for new and expanding facilities. The implementation of the CWS comprises the follow-up of existing initiatives resulting from the application of Phase 1 and the promotion and application of best management practices for new and expanding facilities, the determination and tracking of ancillary emission reductions of benzene realized as a result of other CWS initiatives, and the monitoring and reporting of progress. 13 refs., 4 tabs., 3 figs

  13. Metabolites of benzene are potent inhibitors of gap-junction intercellular communication

    Energy Technology Data Exchange (ETDEWEB)

    Rivedal, Edgar [Norwegian Radium Hospital, Institute for Cancer Research, Montebello, Oslo (Norway); Witz, Gisela [Robert Wood Johnson Medical School/UMDNJ, Environmental and Occupational Health Sciences Institute and Department of Environmental and Occupational Medicine, Piscataway, New Jersey (United States)

    2005-06-01

    Chronic exposure to benzene has been shown to lead to bone marrow depression and the development of leukemia. The mechanism underlying the carcinogenicity of benzene is unknown, although a number of genetic changes including chromosomal aberrations have been associated with benzene toxicity. Metabolism of benzene is required for the induced toxicological effects. We have investigated the effect of trans,trans-muconaldehyde (MUC), hydroquinone (HQ), and four MUC metabolites on gap-junction intercellular communication (GJIC). Inhibition of GJIC has been considered a possible predictor of tumor promoters and non-genotoxic carcinogens, and shown to result in perturbation of hematopoiesis. MUC was found to be a strong inhibitor of GJIC (EC50=12 {mu}mol L{sup -1}) in rat liver epithelial cells IAR20, with potency similar to that of chlordane (EC50=7 {mu}mol L{sup -1}). HQ inhibited GJIC with an EC50 of 25 {mu}mol L{sup -1}, and the metabolite OH/CHO with an EC50 of 58 {mu}mol L{sup -1}. The other MUC metabolites tested, CHO/COOH and OH/COOH were weak inhibitors of GJIC whereas COOH/COOH had no effect. Benzene itself had no effect on GJIC when tested in concentrations up to 20 mmol L{sup -1}. The relative potency observed for the metabolites on GJIC is similar to their hematotoxic effects. The effect of MUC on GJIC was observed to take place concordant with a dramatic loss of connexin 43 (Cx43) from the cells as visualized by Western blotting. Substances with the ability to inhibit Cx43-dependent GJIC have previously been observed to interfere with normal hematopoietic development. The ability of benzene metabolites to interfere with gap-junction functionality, and especially the dramatic loss of Cx43 induced by MUC, should therefore be considered as a possible mechanism for benzene-induced hematotoxicity and development of leukemia. (orig.)

  14. Mechanistically identified suitable biomarkers of exposure, effect, and susceptibility for silicosis and coal-worker's pneumoconiosis: A comprehensive review

    Energy Technology Data Exchange (ETDEWEB)

    Gulumian, M.; Borm, P.J.A.; Vallyathan, V.; Castranova, V.; Donaldson, K.; Nelson, G.; Murray, J. [NIOH, Johannesburg (South Africa). Dept. of Toxicology & Biochemical Research

    2006-09-15

    Clinical detection of silicosis is currently dependent on radiological and lung function abnormalities, both late manifestations of disease. Markers of prediction and early detection of pneumoconiosis are imperative for the implementation of timely intervention strategies. Understanding the underlying mechanisms of the etiology of coal workers pneumoconiosis (CWP) and silicosis was essential in proposing numerous biomarkers that have been evaluated to assess effects following exposure to crystalline silica and/or coal mine dust. Human validation studies have substantiated some of these proposed biomarkers and argued in favor of their use as biomarkers for crystalline silica-and CWP-induced pneumoconiosis. A number of 'ideal' biological markers of effect were identified, namely, Clara cell protein-16 (CC16) (serum), tumor necrosis factor-alpha (TNF-alpha) (monocyte release), interleukin-8 (IL-8) (monocyte release), reactive oxygen species (ROS) measurement by chemiluminescence (neutrophil release), 8-isoprostanes (serum), total antioxidant levels measured by total equivalent antioxidant capacity (TEAC), glutathione, glutathione peroxidase activity, glutathione S-transferase activity, and platelet-derived growth factor (PDGF) (serum). TNF-alpha polymorphism (blood cellular DNA) was identified as a biomarker of susceptibility. Further studies are planned to test the validity and feasibility of these biomarkers to detect either high exposure to crystalline silica and early silicosis or susceptibility to silicosis in gold miners in South Africa.

  15. Radiolysis of Aqueous Benzene Solutions

    International Nuclear Information System (INIS)

    Aerated and deaerated aqueous solutions of benzene have been irradiated with 60Co 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(H2) = 0.44 (0. 43) and G(H2O2) = 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 + H2O2) >> k(H + H2O2). Furthermore, the results indicate that a competition takes place between the reactions: 2 C6H6OH · -> dimer -> biphenyl. C6H7 · + C6H6OH · -> dimer -> biphenyl. The yields in aerated, unbuffered or acid, solutions were: G(phenol) = 2.1 (2.3), G(biphenyl) = 0 (0), and G(H2O2) = 2.2 (3.1), the figures in brackets being valid for acid solutions. The ratio k(H + C6H6)/k(H + O2) was 1.4x10-2. The results indicate that peroxides, or more probably hydroperoxides, take part in the reactions. After the addition of Fe2+ or Fe3+ 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

  16. Detection of Sperm DNA Damage in Workers Exposed to Benzene by Modified Single Cell Gel Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    Bo SONG; Zhi-ming CAI; Xin LI; Li-xia DENG; Qiao ZHANG; Lu-kang ZHENG

    2005-01-01

    Objective To assess the effect of benzene on sperm DNA damageMethods Twenty-seven benzene-exposed workers were selected as exposed groupand 35 normal sperm donors as control group. Air concentration of benzene series inworkshop was determined by gas chromatography. As an internal exposure dose ofbenzene, the concentration of trans, trans-muconic acid (ttMA) was determined byhigh performance liquid chromatography. DNA was detected by modified single cellgel electrophoresis (SCGE).Results The air concentrations of benzene, toluene and xylene at the workplace were86.49 ± 2.83 mg/m3, 97.20 ±3.52 mg/m3 and 97.45 ±2.10 mg/m3, respectively.Urinary ttMA in exposed group (1.040 ± 0.617 mg/L) was significantly higher thanthat of control group (0.819 ± 0.157 mg/L). The percentage of head DNA, determinedby modified SCGE method, significantly decreased in the exposed group (n=13, 70.18%± 7.36%) compared with the control (n=16, 90.62% ± 2.94%)(P<0.001).Conclusion The modified SCGE method can be used to investigate the damage ofsperm DNA. As genotoxin and reprotoxins, benzene had direct effect on the germ cellsduring the spermatogenesiss.

  17. Spatial variability in levels of benzene, formaldehyde, and total benzene, toluene, ethylbenzene and xylenes in New York City: a land-use regression study

    Directory of Open Access Journals (Sweden)

    Kheirbek Iyad

    2012-07-01

    Full Text Available Abstract Background Hazardous air pollutant exposures are common in urban areas contributing to increased risk of cancer and other adverse health outcomes. While recent analyses indicate that New York City residents experience significantly higher cancer risks attributable to hazardous air pollutant exposures than the United States as a whole, limited data exist to assess intra-urban variability in air toxics exposures. Methods To assess intra-urban spatial variability in exposures to common hazardous air pollutants, street-level air sampling for volatile organic compounds and aldehydes was conducted at 70 sites throughout New York City during the spring of 2011. Land-use regression models were developed using a subset of 59 sites and validated against the remaining 11 sites to describe the relationship between concentrations of benzene, total BTEX (benzene, toluene, ethylbenzene, xylenes and formaldehyde to indicators of local sources, adjusting for temporal variation. Results Total BTEX levels exhibited the most spatial variability, followed by benzene and formaldehyde (coefficient of variation of temporally adjusted measurements of 0.57, 0.35, 0.22, respectively. Total roadway length within 100 m, traffic signal density within 400 m of monitoring sites, and an indicator of temporal variation explained 65% of the total variability in benzene while 70% of the total variability in BTEX was accounted for by traffic signal density within 450 m, density of permitted solvent-use industries within 500 m, and an indicator of temporal variation. Measures of temporal variation, traffic signal density within 400 m, road length within 100 m, and interior building area within 100 m (indicator of heating fuel combustion predicted 83% of the total variability of formaldehyde. The models built with the modeling subset were found to predict concentrations well, predicting 62% to 68% of monitored values at validation sites. Conclusions Traffic and

  18. Lead shot contribution to blood lead of First Nations people: The use of lead isotopes to identify the source of exposure

    International Nuclear Information System (INIS)

    Although lead isotope ratios have been used to identify lead ammunition (lead shotshell pellets and bullets) as a source of exposure for First Nations people of Canada, the actual source of lead exposure needs to be further clarified. Whole blood samples for First Nations people of Ontario, Canada, were collected from participants prior to the traditional spring harvest of water birds, as well as post-harvest. Blood-lead levels and stable lead isotope ratios prior to, and after the harvest were determined by ICP-MS. Data were analyzed by paired t-tests and Wilcoxon Signed-Ranks tests. All participants consumed water birds harvested with lead shotshell during the period of study. For the group excluding six males who were potentially exposed to other sources of lead (as revealed through a questionnaire), paired t-tests and Wilcoxon Signed-Ranks tests showed consistent results: significant (p 206Pb/204Pb and 206Pb/207Pb towards the mean values we previously reported for lead shotshell pellets; and a significant decrease in 208Pb/206Pb values towards the mean for lead shotshell pellets. However, when we categorized the group further into a group that did not use firearms and did not eat any other traditional foods harvested with lead ammunition other than waterfowl, our predictions for 206Pb/204Pb, 206Pb/207Pb and 208Pb/206Pb hold true, but there was not a significant increase in blood-lead level after the hunt. It appears that the activity of hunting (i.e., use of a shotgun) was also an important route of lead exposure. The banning of lead shotshell for all game hunting would eliminate a source of environmental lead for all people who use firearms and/or eat wild game

  19. Dehydrogenation of benzene on Pt(111) surface

    Science.gov (United States)

    Gao, W.; Zheng, W. T.; Jiang, Q.

    2008-10-01

    The dehydrogenation of benzene on Pt(111) surface is studied by ab initio density functional theory. The minimum energy pathways for benzene dehydrogenation are found with the nudge elastic band method including several factors of the associated barriers, reactive energies, intermediates, and transient states. The results show that there are two possible parallel minimum energy pathways on the Pt(111) surface. Moreover, the tilting angle of the H atom in benzene can be taken as an index for the actual barrier of dehydrogenation. In addition, the properties of dehydrogenation radicals on the Pt(111) surface are explored through their adsorption energy, adsorption geometry, and electronic structure on the surface. The vibrational frequencies of the dehydrogenation radicals derived from the calculations are in agreement with literature data.

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

    International Nuclear Information System (INIS)

    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 pure

  1. Ionic Liquid Catalyst Used in Deep Desulfuration of the Coking Benzene for Producing Sulfurless Benzene

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xia-Ping; WANG Yan-Liang; MENG Fan-Wei; FAN Xing-Ming; QIN Song-Bo

    2008-01-01

    For the widening need of benzene used in organic synthesis, ionic liquid catalyst was prepared to study the process of deep desulfuration in the coking benzene. The result shows that the effect of de-thiophene by the ionic liquid catalyst (N-methyl imidazolium hydrogen sulfate [Hmim][HSO4]) is related to its acid function value.Hammett indicator was used to determine the acid function value H0 of the ionic liquid. It can be concluded that while the acid function value is in the range from -4 to -12, the ionic liquid catalyst can make the concentration certain acid quantity and strength, the ionic liquid catalyst helps to form alkyl thiophene through Friedel-Crafts reaction, which differs from the character of benzene and it is absolutely necessary for the separation and refinement of benzene. But overabundant quantity and higher acid value of [Hmim][HSO4] are more suitable for the side copolymerization of benzene, thiophene and alkene, thereby affecting repeated use of the ionic liquid catalyst([Hmim][HSO4]). In our research, thiophene derivant produced by desulfurization in the coking benzene was used as the polymer to provide the passing channel of the charges. The ionic liquid composition in poor performance after repeated use was made to prepare conductive material (resisting to static electricity) as an "electron-receiving" and "electron-giving" doping agent. The result shows that thiophene derivant after desulfuration in the coking benzene can be used to prepare doping conductive materials.

  2. The pyrolysis of toluene and ethyl benzene

    Science.gov (United States)

    Sokolovskaya, V. G.; Samgin, V. F.; Kalinenko, R. A.; Nametkin, N. S.

    1987-01-01

    The pyrolysis of toluene at 850 to 950 C gave mainly H2, CH4, and benzene; PhEt at 650 to 750 C gave mainly H2, CH4, styrene, benzene, and toluene. The rate constants for PhEt pyrolysis were 1000 times higher than those for toluene pyrolysis; the chain initiation rate constants differed by the same factor. The activation energy differences were 46 kJ/mole for the total reaction and 54 kJ/mole for chain initiation. The chain length was evaluated for the PhEt case (10 + or - 2).

  3. Determination of dose coefficients and urinary excretion function for inhalation of carbon-14-labelled benzene

    International Nuclear Information System (INIS)

    Based on existing pharmacokinetic models for benzene, the distribution and retention of activity after inhalation of 14C-labelled benzene in humans were studied. Six different benzene concentrations from 0.1 to 10,000 ppm (corresponding to activity concentrations between 9.6 x 106 and 9.6 x 1011 Bq m-3) and five exposure times from 0.1 to 1000 min were considered. The cumulated activities in the different organs and tissues and the urinary excretion rates were observed to depend non-linearly on the activity intake. The fraction of activity removed via urine varies between 52 and 10% of the intake. Nevertheless, for times that are long compared to the exposure duration the urinary excretion rate is determined by the activity clearance from adipose tissue and thus decreases at a constant rate. This decrease is common for all exposure conditions examined and thus allowed determining a mean urinary excretion rate and corresponding dose coefficients for committed equivalent doses as well as for the effective dose. The uncertainty of the dose coefficients is estimated to be about 50% for the exposure range covered. A 14-day interval for the incorporation monitoring by urine activity counting seems to be reasonable. (author)

  4. De novo assembly of the blunt snout bream (Megalobrama amblycephala) gill transcriptome to identify ammonia exposure associated microRNAs and their targets.

    Science.gov (United States)

    Sun, Shengming; Ge, Xianping; Zhu, Jian; Zhang, Wuxiao; Xuan, Fujun

    2016-01-01

    De novo transcriptome sequencing is a robust method for microRNA (miRNA) target gene prediction, especially for organisms without reference genomes. Following exposure of Megalobrama amblycephala to ammonia (0.1 or 20 mg L(-1) ), two cDNA libraries were constructed from the fish gills and sequenced using Illumina HiSeq 2000. Over 90 million reads were generated and de novo assembled into 46, 615 unigenes, which were then extensively annotated by comparing to different protein databases, followed by biochemical pathway prediction. The expression of 2666 unigenes significantly differed; 1961 were up-regulated, while 975 were down-regulated. Among these, 250 unigenes were identified as the targets for 10 conserved and 4 putative novel miRNA families by miRNA target computational prediction. We examined expression of ssa-miRNA-21 and its target genes by real-time quantitative PCR and found agreement with the sequencing data. This study demonstrates the feasibility of identifying miRNA targets by transcriptome analysis. The transcriptome assembly data represent a substantial increase in the genomic resources available for Megalobrama amblycephala and will be useful for gene expression profile analysis and miRNA functional annotation. PMID:27504260

  5. Identifying areas of Australia at risk of H5N1 avian influenza infection from exposure to migratory birds: a spatial analysis

    Directory of Open Access Journals (Sweden)

    Iain J. East

    2008-05-01

    Full Text Available Since 2003, highly pathogenic avian influenza (HPAI due to H5N1 virus has been reported from both domestic poultry and wild birds in 60 countries resulting in the direct death or slaughter of over 250,000,000 birds. The potential exists for HPAI to spread to Australia via migratory shorebirds returning from Asia with the most likely pathway of introduction into commercial poultry flocks involving the transfer of HPAI from migrating shorebirds to native waterfowl species that subsequently interact with poultry on low security poultry farms. Surveillance programmes provide an important early-warning for Australia’s estimated 2,000 commercial poultry farms but, to be efficient, they should be risk-based and target resources at those areas and sectors of the industry at higher risk of exposure. This study compared the distributions of migratory shorebirds and native waterfowl to identify six regions where the likelihood of exotic HPAI incursion and establishment in native waterfowl is highest. Analysis of bird banding records showed that native waterfowl did not move further than 10 km during the spring breeding season when migratory shorebirds arrived in Australia. Therefore, poultry farms within 10 km of significant shorebird habitat in these six regions of highest comparative risk were identified. The final analysis showed that the estimated risk to Australia is low with only two poultry farms, one at Broome and one at Carnarvon, located in the regions of highest risk.

  6. 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

  7. 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...

  8. 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.

  9. Contrastive Analysis of the Raman Spectra of Polychlorinated Benzene: Hexachlorobenzene and Benzene

    Directory of Open Access Journals (Sweden)

    Zhengjun Zhang

    2011-12-01

    Full Text Available Detection of persistent pollutants such as polychlorinated benzene in environment in trace amounts is challenging, but important. It is more difficult to distinguish homologues and isomers of organic pollutantd when present in trace amounts because of their similar physical and chemical properties. In this work we simulate the Raman spectra of hexachlorobenzene and benzene, and figure out the vibration mode of each main peak. The effect on the Raman spectrum of changing substituents from H to Cl is analyzed to reveal the relations between the Raman spectra of homologues and isomers of polychlorinated benzene, which should be helpful for distinguishing one kind of polychlorinated benzene from its homologues and isomers by surface enhanced Raman scattering.

  10. 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...

  11. A co-crystal between benzene and ethane: a potential evaporite material for Saturn's moon Titan

    Directory of Open Access Journals (Sweden)

    Helen E. Maynard-Casely

    2016-05-01

    Full Text Available Using synchrotron X-ray powder diffraction, the structure of a co-crystal between benzene and ethane formed in situ at cryogenic conditions has been determined, and validated using dispersion-corrected density functional theory calculations. The structure comprises a lattice of benzene molecules hosting ethane molecules within channels. Similarity between the intermolecular interactions found in the co-crystal and in pure benzene indicate that the C—H...π network of benzene is maintained in the co-crystal, however, this expands to accommodate the guest ethane molecules. The co-crystal has a 3:1 benzene:ethane stoichiometry and is described in the space group R\\bar 3 with a = 15.977 (1 Å and c = 5.581 (1 Å at 90 K, with a density of 1.067 g cm−3. The conditions under which this co-crystal forms identify it is a potential that forms from evaporation of Saturn's moon Titan's lakes, an evaporite material.

  12. A co-crystal between benzene and ethane: a potential evaporite material for Saturn's moon Titan.

    Science.gov (United States)

    Maynard-Casely, Helen E; Hodyss, Robert; Cable, Morgan L; Vu, Tuan Hoang; Rahm, Martin

    2016-05-01

    Using synchrotron X-ray powder diffraction, the structure of a co-crystal between benzene and ethane formed in situ at cryogenic conditions has been determined, and validated using dispersion-corrected density functional theory calculations. The structure comprises a lattice of benzene molecules hosting ethane molecules within channels. Similarity between the intermolecular interactions found in the co-crystal and in pure benzene indicate that the C-H⋯π network of benzene is maintained in the co-crystal, however, this expands to accommodate the guest ethane molecules. The co-crystal has a 3:1 benzene:ethane stoichiometry and is described in the space group [Formula: see text] with a = 15.977 (1) Å and c = 5.581 (1) Å at 90 K, with a density of 1.067 g cm(-3). The conditions under which this co-crystal forms identify it is a potential that forms from evaporation of Saturn's moon Titan's lakes, an evaporite material. PMID:27158505

  13. Discovering Electronic Effects of Substituents in Nitrations of Benzene Derivatives Using GC-MS Analysis

    Science.gov (United States)

    Clennan, Malgorzata M.; Clennan, Edward L.

    2007-01-01

    The nitration of six benzene derivatives having a range of substituents that differ in electronic effects were followed by GC-MS analyses of the crude reaction mixtures and adapted for the second-year organic laboratory. Students pool their results and identify the products by analyzing the mass spectral data of the isomers and by comparing them…

  14. 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.

  15. Evaluation of genotoxicity in workers exposed to benzene and atmospheric pollutants.

    Science.gov (United States)

    Göethel, Gabriela; Brucker, Natália; Moro, Angela M; Charão, Mariele F; Fracasso, Rafael; Barth, Anelise; Bubols, Guilherme; Durgante, Juliano; Nascimento, Sabrina; Baierle, Marília; Saldiva, Paulo H; Garcia, Solange C

    2014-08-01

    Gas station attendants and taxi drivers are occupationally exposed to xenobiotics which may be harmful to their health. Atmospheric pollutants and benzene can lead to DNA damage. Genotoxicity and mutagenicity assays can be used to evaluate the effects of these pollutants. We have evaluated genotoxicity and mutagenicity in workers occupationally exposed to xenobiotics, by application of the 8-hydroxy-2-deoxyguanosine (8-OHdG), comet, and micronucleus (MN) assays. Biomarkers of benzene and carbon monoxyde exposure were also measured: urinary t,t-muconic acid (t,t-MA) and carboxyhaemoglobin (COHb) in whole blood, respectively. The study groups comprised 43 gas station attendants (GSA), 34 taxi drivers (TD), and 22 persons without known occupational exposures (NE). Levels of t,t-MA in the GSA group were significantly elevated compared to the NE group (p0.05). DNA damage index (DI) and 8-OHdG levels were significantly higher for both the GSA and TD groups, compared to the NE group (p<0.001), but MN frequencies were not elevated. Spearman correlation analysis showed that the frequency of MN was positively correlated with 8-OHdG. A positive correlation between DNA DI levels and 8-OHdG was also observed. In conclusion, our results indicated that low levels of occupational exposure to benzene and atmospheric pollutants may be linked to genotoxicity and oxidative DNA damage. PMID:25344165

  16. Quantitation of Aristolochic Acids in Corn, Wheat Grain, and Soil Samples Collected in Serbia: Identifying a Novel Exposure Pathway in the Etiology of Balkan Endemic Nephropathy.

    Science.gov (United States)

    Chan, Wan; Pavlović, Nikola M; Li, Weiwei; Chan, Chi-Kong; Liu, Jingjing; Deng, Kailin; Wang, Yinan; Milosavljević, Biljana; Kostić, Emina N

    2016-07-27

    While to date investigations provided convincing evidence on the role of aristolochic acids (AAs) in the etiology of Balkan endemic nephropathy (BEN) and upper urothelial cancer (UUC), the exposure pathways by which AAs enter human bodies to cause BEN and UUC remain obscure. The goal of this study is to test the hypothesis that environmental pollution by AAs and root uptake of AAs in the polluted soil may be one of the pathways by which AAs enter the human food chain. The hypothesis driving this study was that the decay of Aristolochia clematitis L., a AA-containing herbaceous plant that is found growing widespread in the endemic regions, could release free AAs to the soil, which could be taken up by food crops growing nearby, thereby transferring this potent human nephrotoxin and carcinogen into their edible parts. Using the highly sensitive and selective high-performance liquid chromatography coupled with fluorescence detection method, we identified and quantitated in this study for the first time AAs in corn, wheat grain, and soil samples collected from the endemic village Kutles in Serbia. Our results provide the first direct evidence that food crops and soil in the Balkans are contaminated with AAs. It is possible that the presence of AAs in edible parts of crops originating from the AA-contaminated soil could be one of the major pathways by which humans become exposed to AAs. PMID:27362729

  17. 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

  18. 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.

  19. Formation of reactive metabolites from benzene

    International Nuclear Information System (INIS)

    Rat liver mitoplasts were incubated first with [3H]dGTP, to form DNA labeled in G, and then with [14C]benzene. The DNA was isolated and upon isopycnic density gradient centrifugation in CsCl yielded a single fraction of DNA labeled with both [3H] and [14C]. 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. [3H]Deoxyguanosine was reacted with [14C]hydroquinone or benzoquinone. The product was characterized using uv, fluorescence, mass and NMR spectroscopy. A proposed structure is described. (orig.)

  20. Nonlinear diffusion in Acetone-Benzene Solution

    CERN Document Server

    Obukhovsky, Vjacheslav V

    2010-01-01

    The nonlinear diffusion in multicomponent liquids under chemical reactions influence has been studied. The theory is applied to the analysis of mass transfer in a solution of acetone-benzene. It has been shown, that the creation of molecular complexes should be taken into account for the explanation of the experimental data on concentration dependence of diffusion coefficients. The matrix of mutual diffusivities has been found and effective parameters of the system have been computed.

  1. PROCESS SIMULATION OF BENZENE SEPARATION COLUMN OF LINEAR ALKYL BENZENE (LABPLANT

    Directory of Open Access Journals (Sweden)

    Zaid A. AbdelRahman

    2013-05-01

    Full Text Available       CHEMCAD process simulator was used for the analysis of existing benzene separation column in LAB plant(Arab Detergent Company/Beiji-Iraq.         Simulated column performance curves were constructed. The variables considered in this study are the thermodynamic model option, top and bottom temperatures, feed temperature, feed composition & reflux ratio. Also simulated columns profiles for the temperature, vapor & liquid flow rates compositions, were constructed. Four different thermodynamic models options (SRK, TSRK, PR, and ESSO were used, affecting the results within 1-25% variation for the most cases.            For Benzene Column (32 real stages, feed stage 14, the simulated results show that bottom temperature above 200 oC the weight fractions of top components, except benzene, increases sharply, where as benzene top weight fraction decreasing sharply. Also, feed temperature above 180 oC  shows same trends. The column profiles remain fairly constant from tray 3 (immediately below condenser to tray 10 (immediately above feed and from tray 15 (immediately below feed to tray 25 (immediately above reboiler. Simulation of the benzene separation column in LAB production plant using CHEMCAD simulator, confirms the real plant operation data. The study gives evidence about a successful simulation with CHEMCAD.

  2. At-line benzene monitor for measuring benzene in precipitate hydrolysis aqueous

    Energy Technology Data Exchange (ETDEWEB)

    Jenkins, W.J.

    1992-10-14

    A highly accurate and repeatable at-line benzene monitor (ALBM) has been developed to measure the benzene concentration in precipitate hydrolysis aqueous (PHA) in the DWPF. This analyzer was conceived and jointly developed within SRTC by the Analytical Development and the Defense Waste Process Technology Sections with extensive support from the Applied Statistics Group and the TNX Operations Section. It is recommended that an ALBM specifically adapted to DWPF analytical requirements be used to measure benzene in PHA; calibrations be performed using a 10% methanol solution matrix (for standard stability); and based on experience gained in development at TNX, the services of ADS and ASG be employed to both adapt the ALBM to DWPF requirements and develop statistical control procedures.

  3. At-line benzene monitor for measuring benzene in precipitate hydrolysis aqueous

    International Nuclear Information System (INIS)

    A highly accurate and repeatable at-line benzene monitor (ALBM) has been developed to measure the benzene concentration in precipitate hydrolysis aqueous (PHA) in the DWPF. This analyzer was conceived and jointly developed within SRTC by the Analytical Development and the Defense Waste Process Technology Sections with extensive support from the Applied Statistics Group and the TNX Operations Section. It is recommended that an ALBM specifically adapted to DWPF analytical requirements be used to measure benzene in PHA; calibrations be performed using a 10% methanol solution matrix (for standard stability); and based on experience gained in development at TNX, the services of ADS and ASG be employed to both adapt the ALBM to DWPF requirements and develop statistical control procedures

  4. The molecular mechanisms of liver and islets of Langerhans toxicity by benzene and its metabolite hydroquinone in vivo and in vitro.

    Science.gov (United States)

    Bahadar, Haji; Maqbool, Faheem; Mostafalou, Sara; Baeeri, Maryam; Gholami, Mahdi; Ghafour-Boroujerdi, Elmira; Abdollahi, Mohammad

    2015-01-01

    Benzene (C6H6) is one of the most commonly used industrial chemicals causing environmental pollution. This study aimed to examine the effect of benzene and its metabolite hydroquinone on glucose regulating organs, liver and pancreas, and to reveal the involved toxic mechanisms, in rats. In the in vivo part, benzene was dissolved in corn oil and administered through intragastric route at doses of 200, 400 and 800 mg/kg/day, for 4 weeks. And, in the in vitro part, toxic mechanisms responsible for weakening the antioxidant system in islets of Langerhans by hydroquinone at different concentrations (0.25, 0.5 and 1 mM), were revealed. Benzene exposure raised the activity of phosphoenolpyruvate carboxykinase (PEPCK), glucose 6-phosphatase (G6Pase) enzymes and increased fasting blood sugar (FBS) in comparison to control animals. Also, the activity of hepatic glucokinase (GK) was decreased significantly. Along with, a significant increase was observed in hepatic tumor necrosis factor (TNF-α) and plasma insulin in benzene treated rats. Moreover, benzene caused a significant rise in hepatic lipid peroxidation, DNA damage and oxidation of proteins. In islets of Langerhans, hydroquinone was found to decrease the capability of antioxidant system to fight free radicals. Also, the level of death proteases (caspase 3 and caspase 9) was found higher in hydroquinone exposed islets. The current study demonstrated that benzene and hydroquinone causes toxic effects on liver and pancreatic islets by causing oxidative impairment. PMID:26056850

  5. Induction of molecular chirality by circularly polarized light in cyclic azobenzene with a photoswitchable benzene rotor.

    Science.gov (United States)

    Hashim, P K; Thomas, Reji; Tamaoki, Nobuyuki

    2011-06-20

    New phototriggered molecular machines based on cyclic azobenzene were synthesized in which a 2,5-dimethoxy, 2,5-dimethyl, 2,5-difluorine or unsubstituted-1,4-dioxybenzene rotating unit and a photoisomerizable 3,3'-dioxyazobenzene moiety are bridged together by fixed bismethylene spacers. Depending upon substitution on the benzene moiety and on the E/Z conformation of the azobenzene unit, these molecules suffer various degrees of restriction on the free rotation of the benzene rotor. The rotation of the substituted benzene rotor within the cyclic azobenzene cavity imparts planar chirality to the molecules. Cyclic azobenzene 1, with methoxy groups at both the 2- and 5-positions of the benzene rotor, was so conformationally restricted that free rotation of the rotor was prevented in both the E and Z isomers and the respective planar chiral enantiomers were resolved. In contrast, compound 2, with 2,5-dimethylbenzene as the rotor, demonstrated the property of a light-controlled molecular brake, whereby rotation of the 2,5-dimethylbenzene moiety is completely stopped in the E isomer (brake ON, rotation OFF), while the rotation is allowed in the Z isomer (brake OFF, rotation ON). The cyclic azobenzene 3, with fluorine substitution on the benzene rotor, was in the brake OFF state regardless of E/Z photoisomerization of the azobenzene moiety. More interestingly, for the first time, we demonstrated the induction of molecular chirality in a simple monocyclic azobenzene by circular-polarized light. The key characteristics of cyclic azobenzene 2, that is, stability of the chiral structure in the E isomer, fast racemization in the Z isomer, and the circular dichroism of enantiomers of both E and Z isomers, resulted in a simple reversible enantio-differentiating photoisomerization directly between the E enantiomers. Upon exposure to r- or l-circularly polarized light at 488 nm, partial enrichment of the (S)- or (R)-enantiomers of 2 was observed. PMID:21567494

  6. Crystal structure of a benzene sorption complex of dehydrated fully Cd2+-exchanged zeolite x

    International Nuclear Information System (INIS)

    The crystal structure of a benzene sorption complex of fully dehydrated Cd2+-exchanged zeolite X, Cd46Si100Al92-O384·43C6H6 (a=24.880(6) A), has been determined by single-crystal X-ray diffraction techniques in the cubic space group Fd3 at 21.deg.C. The crystal was prepared by ion exchange in a flowing stream of 0.05 M aqueous Cd(NO3)2 for 3 d, followed by dehydration at 400.deg.C and 2x10-6 Torr for 2 d, followed by exposure to about 92 Torr of benzene vapor at 22.deg.C. The structure was determined in this atmosphere and refined to the final error indices R1=0.054 and Rw=0.066 with 561 reflections for which I>3σ(I). In this structure, Cd2+ ions are found at four crystallographic sites: eleven Cd2+ ions are at site I, at the centers of the double six-oxygen rings; six Cd2+ ions lie at site I', in the sodalite cavity opposite to the double six-oxygen rings; and the remaining 29 Cd2+ ions are found at two nonequivalent threefold axes of unit cell, site II' (in the sodalite cavity ) and site II (in the supercage) with occupancies of 2 and 27 ions, respectively. Each of these Cd2+ ions coordinates to three framework oxygens, either at 2.173(13) or 2.224(10) A, respectively, and extends 0.37 A into the sodalite unit or 0.60 A into the supercage from the plane of the three oxygens to which it is bound. The benzene molecules are found at two distinct sites within the supercages. Twenty-seven benzenes lie on threefold axes in the large cavities where they interact facially with the latter 27 site-II Cd2+ ions (Cd2+-benzene center=2.72 A; occupancy=27 molecules/32 sites). The remaining sixteen benzene molecules are found in 12-ring planes; occupancy=16 molecules/16 sites. Each hydrogen of these sixteen benzenes is ca. 2.8/3.0 A from three 12-ring oxygens where each is stabilized by multiple weak electrostatic and van der Waals interactions with framework oxygens

  7. A methodological frame for assessing benzene induced leukemia risk mitigation due to policy measures

    International Nuclear Information System (INIS)

    The study relies on the development of a methodology for assessing the determinants that comprise the overall leukemia risk due to benzene exposure and how these are affected by outdoor and indoor air quality regulation. An integrated modeling environment was constructed comprising traffic emissions, dispersion models, human exposure models and a coupled internal dose/biology-based dose–response risk assessment model, in order to assess the benzene imposed leukemia risk, as much as the impact of traffic fleet renewal and smoking banning to these levels. Regarding traffic fleet renewal, several “what if” scenarios were tested. The detailed full-chain methodology was applied in a South-Eastern European urban setting in Greece and a limited version of the methodology in Helsinki. Non-smoking population runs an average risk equal to 4.1 · 10−5 compared to 23.4 · 10−5 for smokers. The estimated lifetime risk for the examined occupational groups was higher than the one estimated for the general public by 10–20%. Active smoking constitutes a dominant parameter for benzene-attributable leukemia risk, much stronger than any related activity, occupational or not. From the assessment of mitigation policies it was found that the associated leukemia risk in the optimum traffic fleet scenario could be reduced by up to 85% for non-smokers and up to 8% for smokers. On the contrary, smoking banning provided smaller gains for (7% for non-smokers, 1% for smokers), while for Helsinki, smoking policies were found to be more efficient than traffic fleet renewal. The methodology proposed above provides a general framework for assessing aggregated exposure and the consequent leukemia risk from benzene (incorporating mechanistic data), capturing exposure and internal dosimetry dynamics, translating changes in exposure determinants to actual changes in population risk, providing a valuable tool for risk management evaluation and consequently to policy support. - Highlights:

  8. 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.

  9. Quantification of volatile organic compounds in smoke from prescribed burning and comparison with occupational exposure limits

    Science.gov (United States)

    Romagnoli, E.; Barboni, T.; Santoni, P.-A.; Chiaramonti, N.

    2014-05-01

    Prescribed burning represents a serious threat to personnel fighting fires due to smoke inhalation. The aim of this study was to investigate exposure by foresters to smoke from prescribed burning, focusing on exposure to volatile organic compounds (VOCs). The methodology for smoke sampling was first evaluated. Potentially dangerous compounds were identified among the VOCs emitted by smoke fires at four prescribed burning plots located around Corsica. The measured mass concentrations for several toxic VOCs were generally higher than those measured in previous studies due to the experimental framework (short sampling distance between the foresters and the flame, low combustion, wet vegetation). In particular, benzene, phenol and furfural exceeded the legal short-term exposure limits published in Europe and/or the United States. Other VOCs such as toluene, ethybenzene or styrene remained below the exposure limits. In conclusion, clear and necessary recommendations were made for protection of personnel involved in fighting fires.

  10. 40 CFR 80.1238 - How is a refinery's or importer's average benzene concentration determined?

    Science.gov (United States)

    2010-07-01

    ... average benzene concentration determined? 80.1238 Section 80.1238 Protection of Environment ENVIRONMENTAL... Benzene Gasoline Benzene Requirements § 80.1238 How is a refinery's or importer's average benzene concentration determined? (a) The average benzene concentration of gasoline produced at a refinery or...

  11. 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 degradati

  12. Quantification of the volatile organic compounds in the smoke from prescribed burning and comparison with the occupational exposure limits

    Science.gov (United States)

    Barboni, T.; Santoni, P.-A.

    2013-11-01

    Prescribed burning represents a serious threat to the personnel fighting fires because of smoke inhalation. This study aims to increase the knowledge about foresters exposure to the prescribed burning smoke by focusing on exposure to volatile organic compounds (VOCs). We initially assessed the methodology for smoke sampling. Then, we identified potentially dangerous molecules among the VOCs identified at 4 prescribed burning sites located around Corsica. The values measured were very high, exceeding the exposure limits, particularly for benzene, phenol, and furfural, whose concentrations were above short-term exposure limit (STEL) values. In conclusion, obvious but necessary recommendations were made for the protection of the personnel involved in fighting fires on a professional basis.

  13. Quantification of the volatile organic compounds in the smoke from prescribed burning and comparison with the occupational exposure limits

    Directory of Open Access Journals (Sweden)

    T. Barboni

    2013-11-01

    Full Text Available Prescribed burning represents a serious threat to the personnel fighting fires because of smoke inhalation. This study aims to increase the knowledge about foresters exposure to the prescribed burning smoke by focusing on exposure to volatile organic compounds (VOCs. We initially assessed the methodology for smoke sampling. Then, we identified potentially dangerous molecules among the VOCs identified at 4 prescribed burning sites located around Corsica. The values measured were very high, exceeding the exposure limits, particularly for benzene, phenol, and furfural, whose concentrations were above short-term exposure limit (STEL values. In conclusion, obvious but necessary recommendations were made for the protection of the personnel involved in fighting fires on a professional basis.

  14. Identifying Housing and Meteorological Conditions Influencing Residential Air Exchange Rates in the DEARS and RIOPA Studies: Development of Distributions for Human Exposure Modeling

    Science.gov (United States)

    Appropriate prediction of residential air exchange rate (AER) is important for estimating human exposures in the residential microenvironment, as AER drives the infiltration of outdoor-generated air pollutants indoors. AER differences among homes may result from a number of fact...

  15. 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. PMID:19603680

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

    International Nuclear Information System (INIS)

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

  17. 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. PMID:25960203

  18. An efficient synthesis of substituted benzene-1,2-dicarboxaldehydes

    Institute of Scientific and Technical Information of China (English)

    ZHU Peter C; WANG Dei-Haw; LU Kaitao; MANI Neelakandha

    2007-01-01

    Substituted-benzene-1,2-dicarbaldehydes were synthesized by the reaction of substituted-1,2-bis (dibromomethyl) benzenes with fuming sulfuric acid, followed by hydrolysis, The yields were significantly improved by introducing solid sodium bicarbonate into the reaction mixture before hydrolysis and workup.

  19. An efficient synthesis of substituted benzene-1,2-dicarboxaldehydes

    Institute of Scientific and Technical Information of China (English)

    ZHU; Peter; C; WANG; Der-Haw; MANI; Neelakandha

    2007-01-01

    Substituted-benzene-1,2-dicarbaldehydes were synthesized by the reaction of substituted-1,2-bis(dibromomethyl) benzenes with fuming sulfuric acid,followed by hydrolysis. The yields were signifi-cantly improved by introducing solid sodium bicarbonate into the reaction mixture before hydrolysis and workup.

  20. 1,4-Bis[(2-pyridylethyliminomethyl]benzene

    Directory of Open Access Journals (Sweden)

    Haleden Chiririwa

    2011-04-01

    Full Text Available In the title compound, C22H22N4, the centroid of the benzene ring is located on an inversion centre. The dihedral angle between the benzene and pyridine rings is 10.94 (5°. The crystal structure displays weak intermolecular C—H...N hydrogen bonding and C—H...π interactions.

  1. Air pollution monitoring in Como urban areas. Benzene

    International Nuclear Information System (INIS)

    This work presents the results of a physical - statistical analysis of concentrations of benzene, measured in the Como Center station from 1996 to 1999. The analysis, conducted by means of the development, by steps, of a multifactorial linear regression model, permitted to find an annual trend of benzene, independently from the influence of meteorologicals variables. It has been seen a decrease of concentrations of benzene, from 1997 to 1999, that may be correlate to a decrease of tenor of benzene in the petrol. At the same time, the results of the model permit to understand the role and the relative weight of different climatic factors on the concentrations of benzene. It has been investigated the presence of daily, weekly and seasonal trend, too

  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. 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.

  4. Non-methane exhaust composition in the sydney harbour tunnel: A focus on benzene and 1,3-butadiene

    Science.gov (United States)

    Duffy, Bronwyn L.; Nelson, Peter F.

    The concentrations of individual hydrocarbon species in the Sydney Harbour Tunnel were measured and used to estimate the average composition of emissions from moving motor vehicles in the Sydney urban area. The mean composition of non-methane hydrocarbons in the tunnel air on a weight basis was relatively constant. The mean concentrations for benzene and 1,3-butadiene were 45 and 13 ppbv, respectively, which in turn represented ˜ 5.2% w/w and ˜ 1.0% w/w of the total non-methane C 2C 10 hydrocarbons in the tunnel air. The unit risk factor and the maximum incremental reactivity factor for 1 1,3-butadiene are approximately 30 times higher and 25 times higher, respectively, than the corresponding values for benzene. The concentration (μg m -3) of benzene, however, is only about 5 times that of 1,3-butadiene. On this basis, the relative contribution to the risk associated with exposure to fresh motor vehicle emissions in Sydney would be about 6 times higher for 1,3-butadiene than for benzene. Similarly, the contribution made by 1,3-butadiene to the total hydrocarbon reactivity of the tunnel air will be about 5 times that of benzene. Samples of three different grades of petrol (leaded, unleaded and premium unleaded) from three different brands of fuel were also analysed on two separate occasions. Compositions of leaded and standard unleaded petrol averaged across the three different brands are quite similar. The average aromatic content (% w/w) of the 3 different commercial brands were ˜ 35 and 30% for leaded and unleaded petrol, respectively. However, premium unleaded petrol has a much higher aromatic content of ˜ 47% w/w. Comparison of the petrol and tunnel compositions demonstrated that benzene is enriched relative to other aromatics in exhaust compared to its proportion in the petrol.

  5. 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.

  6. A Quantum Monte Carlo Study of mono(benzene)TM and bis(benzene)TM Systems

    CERN Document Server

    Bennett, M Chandler; Mitas, Lubos

    2016-01-01

    We present a study of mono(benzene)TM and bis(benzene)TM systems, where TM={Mo,W}. We calculate the binding energies by quantum Monte Carlo (QMC) approaches and compare the results with other methods and available experiments. The orbitals for the determinantal part of each trial wave function were generated from several types of DFT in order to optimize for fixed-node errors. We estimate and compare the size of the fixed-node errors for both the Mo and W systems with regard to the electron density and degree of localization in these systems. For the W systems we provide benchmarking results of the binding energies, given that experimental data is not available.

  7. Effects of long- or short-term exposure to a calf identified as persistently infected with bovine viral diarrhea virus on feedlot performance of freshly weaned, transport-stressed beef heifers.

    Science.gov (United States)

    Elam, N A; Thomson, D U; Gleghorn, J F

    2008-08-01

    A single experiment with a completely randomized design was conducted to evaluate the effects of long- or short-term exposure to a calf identified as persistently infected with bovine viral diarrhea virus (PI-BVD) on feedlot performance and carcass characteristics of freshly weaned, transport-stressed beef heifers. Two hundred eighty-eight heifers that had been vaccinated for BVD before weaning and transport were processed and given a metaphylactic antibiotic treatment at arrival and were fed common receiving, growing, and finishing diets for a 215-d period. Treatments were designed to directly or adjacently expose the cattle to a PI-BVD heifer. Directly exposed treatments were 1) negative control with no PI-BVD calf exposure (control), 2) PI-BVD calf commingled in the pen for 60 h and then removed (short-term exposure), and 3) PI-BVD calf commingled in the pen for the duration of the study (long-term exposure); and spatially exposed treatments were 1) negative control with no PI-BVD calf exposure (adjacent pen control), 2) PI-BVD calf commingled in the adjacent pen for 60 h and then removed (adjacent pen short-term exposure), and 3) PI-BVD calf commingled in the adjacent pen for the duration of the study (adjacent pen long-term exposure). Exposure to a PI calf transiently (60 h) or for the duration of the feeding period (215 d) did not affect (P > or = 0.25) final BW compared with heifers that were not exposed. Neither period nor overall DMI was affected (P > or = 0.37) by PI-BVD calf exposure, and no differences (P > or = 0.44) were observed between short- and long-term exposed heifers in the direct or spatially exposed groups. Likewise, total trial ADG was not affected (P > or = 0.36) and overall efficiency of gain (P > or = 0.19) was unaffected by PI-BVD calf exposure in the direct or spatially exposed groups. The results from this study suggest that exposing previously vaccinated, freshly weaned, transport- stressed beef calves to a calf that is persistently

  8. Thermal decomposition of norbornane (bicyclo[2.2.1]heptane) dissolved in benzene. Experimental study and mechanism investigation

    CERN Document Server

    Herbinet, Olivier; Battin-Leclerc, Fr{é}d{é}rique; Fournet, Ren{é}; Marquaire, Paul-Marie

    2007-01-01

    The thermal decomposition of norbornane (dissolved in benzene) has been studied in a jet stirred reactor at temperatures between 873 and 973 K, at residence times ranging from 1 to 4 s and at atmospheric pressure, leading to conversions from 0.04 to 22.6%. 25 reaction products were identified and quantified by gas chromatography, amongst which the main ones are hydrogen, ethylene and 1,3-cyclopentadiene. A mechanism investigation of the thermal decomposition of the norbornane - benzene binary mixture has been performed. Reactions involved in the mechanism have been reviewed: unimolecular initiations 1 by C-C bond scission of norbornane, fate of the generated diradicals, reactions of transfer and propagation of norbornyl radicals, reactions of benzene and cross-coupling reactions.

  9. Modulation of Ras signaling alters the toxicity of hydroquinone, a benzene metabolite and component of cigarette smoke

    International Nuclear Information System (INIS)

    Benzene is an established human leukemogen, with a ubiquitous environmental presence leading to significant population exposure. In a genome-wide functional screen in the yeast Saccharomyces cerevisiae, inactivation of IRA2, a yeast ortholog of the human tumor suppressor gene NF1 (Neurofibromin), enhanced sensitivity to hydroquinone, an important benzene metabolite. Increased Ras signaling is implicated as a causal factor in the increased pre-disposition to leukemia of individuals with mutations in NF1. Growth inhibition of yeast by hydroquinone was assessed in mutant strains exhibiting varying levels of Ras activity. Subsequently, effects of hydroquinone on both genotoxicity (measured by micronucleus formation) and proliferation of WT and Nf1 null murine hematopoietic precursors were assessed. Here we show that the Ras status of both yeast and mammalian cells modulates hydroquinone toxicity, indicating potential synergy between Ras signaling and benzene toxicity. Specifically, enhanced Ras signaling increases both hydroquinone-mediated growth inhibition in yeast and genotoxicity in mammalian hematopoetic precursors as measured by an in vitro erythroid micronucleus assay. Hydroquinone also increases proliferation of CFU-GM progenitor cells in mice with Nf1 null bone marrow relative to WT, the same cell type associated with benzene-associated leukemia. Together our findings show that hydroquinone toxicity is modulated by Ras signaling. Individuals with abnormal Ras signaling could be more vulnerable to developing myeloid diseases after exposure to benzene. We note that hydroquinone is used cosmetically as a skin-bleaching agent, including by individuals with cafe-au-lait spots (which may be present in individuals with neurofibromatosis who have a mutation in NF1), which could be unadvisable given our findings

  10. Benzene conversion by manganese dioxide assisted silent discharge plasma

    Institute of Scientific and Technical Information of China (English)

    LU Bin; JI Min; YU Xin; FENG Tao; YAO Shuiliang

    2007-01-01

    Non-thermal plasma technologies have shown their promising potential specially for the low concentration of volatile organic compound control in indoor air in recent years.But it is also high energy consuming.So,to improve the energy efficiency,adding catalysts which enhance the plasma chemical reactions to plasma reactors may be a good selection.Therefore,in this study the manganese dioxide assisted silent discharge plasma was developed for benzene conversion at a relatively high energy efficiency.The results show that MnO2 could promote complete oxidation of benzene with O2 and O3 produced in the plasma discharge zone.The energy efficiency of benzene conversion with MnO2 was two folds as much as that without catalysts.It was also found that the site of MnO2 in the reactor and the energy density had effects on benzene conversion.While the energy density was lower than 48 J/L,benzene conversion decreased with the increase in the distance between MnO2 bed and the plasma discharge zone.Whereas when the energy density was higher than 104 J/L,benzene conversion had an optimal value that was governed by the distance between MnO2 bed and the plasma discharge zone.The mechanism of benzene oxidation in plasma discharges and over MnO2 is discussed in detail.

  11. 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. PMID:18386150

  12. 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. PMID:26072048

  13. Exacerbation of benzene pneumotoxicity in connexin 32 knockout mice: enhanced proliferation of CYP2E1-immunoreactive alveolar epithelial cells

    International Nuclear Information System (INIS)

    The pulmonary pathogenesis triggered by benzene exposure was studied. Since the role of the connexin 32 (Cx32) gap junction protein in mouse pulmonary pathogenesis has been suggested, in the present study, we explored a possible role of Cx32 in benzene-induced pulmonary pathogenesis using the wild-type (WT) and Cx32 knockout (KO) mice. The mice were exposed to 300 ppm benzene by inhalation for 6 h per day, 5 days per week for a total of 26 weeks, and then sacrificed to evaluate the pneumotoxicity or allowed to live out their life span to evaluate the reversibility of the lesions and tumor incidence. Our results clearly revealed exacerbated pneumotoxicity in the benzene-exposed Cx32 KO mice, characterized by diffuse granulomatous interstitial pneumonia, markedly increased mucin secretion of bronchial/bronchiolar and alveolar epithelial cells, and hyperplastic alveolar epithelial cells positive for CYP2E1. But the results did not indicate any enhancement of pulmonary tumorigenesis in the Cx32 KO mice though the number of animals was small

  14. 40 CFR 80.1285 - How does a refiner apply for a benzene baseline?

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false How does a refiner apply for a benzene... PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Benzene Averaging, Banking and Trading (abt) Program § 80.1285 How does a refiner apply for a benzene baseline? (a) A benzene...

  15. 40 CFR 80.1220 - What are the implementation dates for the gasoline benzene program?

    Science.gov (United States)

    2010-07-01

    ... the gasoline benzene program? 80.1220 Section 80.1220 Protection of Environment ENVIRONMENTAL... Benzene General Information § 80.1220 What are the implementation dates for the gasoline benzene program? (a) Benzene standard. (1) For the annual averaging period beginning January 1, 2011, and for...

  16. Profiling of Biomarkers for the Exposure of Polycyclic Aromatic Hydrocarbons: Lamin-A/C Isoform 3, Poly[ADP-ribose] Polymerase 1, and Mitochondria Copy Number Are Identified as Universal Biomarkers

    Directory of Open Access Journals (Sweden)

    Hwan-Young Kim

    2014-01-01

    Full Text Available This study investigated the profiling of polycyclic aromatic hydrocarbon- (PAH- induced genotoxicity in cell lines and zebrafish. Each type of cells displayed different proportionality of apoptosis. Mitochondrial DNA (mtDNA copy number was dramatically elevated after 5-day treatment of fluoranthene and pyrene. The notable deregulated proteins for PAHs exposure were displayed as follows: lamin-A/C isoform 3 and annexin A1 for benzopyrene; lamin-A/C isoform 3 and DNA topoisomerase 2-alpha for pentacene; poly[ADP-ribose] polymerase 1 (PARP-1 for fluoranthene; and talin-1 and DNA topoisomerase 2-alpha for pyrene. Among them, lamin-A/C isoform 3 and PARP-1 were further confirmed using mRNA and protein expression study. Obvious morphological abnormalities including curved backbone and cardiomegaly in zebrafish were observed in the 54 hpf with more than 400 nM of benzopyrene. In conclusion, the change of mitochondrial genome (increased mtDNA copy number was closely associated with PAH exposure in cell lines and mesenchymal stem cells. Lamin-A/C isoform 3, talin-1, and annexin A1 were identified as universal biomarkers for PAHs exposure. Zebrafish, specifically at embryo stage, showed suitable in vivo model for monitoring PAHs exposure to hematopoietic tissue and other organs.

  17. 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.

  18. 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

  19. Magnetically rotational reactor for absorbing benzene emissions by ionic liquids

    Institute of Scientific and Technical Information of China (English)

    Yangyang; Jiang; Chen; Guo; Huizhou; Liu

    2007-01-01

    A magnetically rotational reactor (MRR) has been developed and used in absorbing benzene emissions. The MRR has a permanent magnet core and uses magnetic ionic liquid [bmim]FeCl4 as absorbent. Benzene emissions were carried by N2 into the MRR and were absorbed by the magnetic ionic liquid. The rotation of the permanent magnet core provided impetus for the agitation of the magnetic ionic liquid, enhancing mass transfer and making benzene better dispersed in the absorbent. 0.68 g benzene emissions could be absorbed by a gram of [bmim]FeCl4, 0.27 and 0.40 g/ghigher than that by [bmim]PF6 and [bmim]BF4, respectively. The absorption rate increased with increasing rotation rate of the permanent magnet.

  20. A comprehensive assessment of mercury exposure in penguin populations throughout the Southern Hemisphere: Using trophic calculations to identify sources of population-level variation

    International Nuclear Information System (INIS)

    Highlights: • Mercury concentrations documented for 10 species of penguins (26 breeding populations). • Mercury concentrations ⩽2.00 ppm in feathers from 18/26 penguin populations. • Trophic level calculations revealed source of population-level variation in mercury. • First documentation of geographic mercury ‘hotspots’ for penguin populations. - Abstract: 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 (⩽2.00 ppm) 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

  1. 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.......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....

  2. Neurobehavioral performance in adolescents is inversely associated with traffic exposure

    OpenAIRE

    Kicinski, Michal; Vermeir, Griet; Van Larebeke, Nicolas; Den Hond, Elly; Schoeters, Greet; Bruckers, Liesbeth; Sioen, Isabelle; Bijnens, Esmée; Roels, Harry A.; Baeyens, Willy; Viaene, Mineke K; Nawrot, Tim S.

    2015-01-01

    On the basis of animal research and epidemiological studies in children and elderly there is a growing concern that traffic exposure may affect the brain. The aim of our study was to investigate the association between traffic exposure and neurobehavioral performance in adolescents. We examined 606 adolescents. To model the exposure, we constructed a traffic exposure factor based on a biomarker of benzene (urinary trans,trans-muconic acid) and the amount of contact with traffic preceding the ...

  3. 2H NMR study of dynamics of benzene-d6 interacting with humic and fulvic acids.

    Science.gov (United States)

    Eastman, Margaret A; Brothers, Lucinda A; Nanny, Mark A

    2011-05-01

    Samples of three humic acids and one fulvic acid with 1% loading of benzene-d(6) in sealed glass tubes have been studied with solid-state deuterium quadrupole-echo nuclear magnetic resonance spectroscopy. Calculated spectra combining three motional models, two isotropic models and a third more restricted small-angle wobble (SAW) motional model, are fit to the experimental spectra. One isotropic motion (ISO(v)) is assigned to vaporous benzene-d(6) due to the small line width, short T(1), and the loss of this component by about -25 °C when the temperature is lowered. The remaining two motional components, ISO(s) and SAW, are sorbed by the humic or fulvic acid. Benzene-d(6) slowly interacts with the humic substances, progressively filling SAW sites as ISO(s) motion diminishes. Both the sorption and increase in percentage of SAW motion are for the most part complete within 200 days but continue to a lesser extent over a period of a few years. For the SAW motion there are at least two and most likely a series of T(1) values, indicating more than one adsorption environment. Enthalpies of sorption, obtained from application of the van't Hoff equation to the percentages of the different motional models derived from a series of variable temperature spectra, are comparable in magnitude to the enthalpy of vaporization of benzene. In Leonardite humic acid, ΔH and ΔS for the ISO(s) to SAW transition change from positive to negative values with age, implying a transition in the driving force from an entropic effect associated with expansion and deformation in the molecular structure of the humic substance to accommodate benzene-d(6) to an enthalpic effect of strong benzene-d(6)-humic substance interactions. In contrast, at advanced ages, Suwannee River humic and fulvic acids have small positive or near zero ΔH and positive ΔS for the ISO(s) to SAW transition. PMID:21456559

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

    International Nuclear Information System (INIS)

    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.)

  5. Differences in xenobiotic detoxifying activities between bone marrow stromal cells from mice and rats: Implications for benzene-induced hematotoxicity

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Hong; Li, Yunbo; Trush, M.A. [Johns Hopkins Univ. School of Hygiene and Public Health, Baltimore, MD (United States)

    1995-10-01

    benzene is a human carcinogen; exposure can result in aplastic anemia and leukemia. Data from animal models are frequently used in benzene risk assessment. In rodent studies, mice are more sensitive to benzene-induced hematotoxicity than rats. Bone marrow stromal cells from mice were significantly more susceptible to the cytotoxicity induced by the benzene metabolites hydroquinone (HQ) and benzoquinone (BQ) than cells from rats. Since cellular gluthathione (GSH) and quinone reductase (QR) are known to play critical roles in modulating HQ-induced cytotoxicity, the GSH content and the QR and glutathione S-transferase (GST) activity in stromal cells from both species was measured. In rat cells, the GSH content and the QR specific activity were 2 and 28 times as much as those from mice, respectively. GSH and QR in both mouse and rat stromal cells were inducible by 1,2-dithiole-3-thione (D3T). D3T pretreatment of both mouse and rat stromal cells resulted in a marked protection against HQ-induced toxicity. Pretreatment of both mouse and rat stromal cells with GSH ethyl ester also provided a dramatic protection against HQ-induced toxicity. Conversely, dicoumarol, an inhibitor of QR, enhanced the HQ-induced toxicity in stromal cells from both mice and rats, indicating an important role for QR in modulating HQ-induced stromal toxicity. Buthionine sulfoximine (BSO), which depleted GSH significantly in both species, potentiated the HQ-induced toxicity in mouse but not in rat stromal cells. Surprisingly, incubation of stromal cells with BSO resulted in a significant induction of QR, especially in rats. Overall, this study demonstrates that the differences in stromal cellular GSH content and QR activity between mice and rats contribute to their respective susceptibility to HQ-induced cytotoxicity in vitro, and may be involved in the greater in vivo sensitivity of mice to benzene-induced hematotoxicity. 51 refs., 9 figs., 1 tab.

  6. Genotoxicity and apoptosis in Drosophila melanogaster exposed to benzene, toluene and xylene: Attenuation by quercetin and curcumin

    International Nuclear Information System (INIS)

    Monocyclic aromatic hydrocarbons (MAHs) such as benzene, toluene and xylene are being extensively used for various industrial and household purposes. Exposure to these hydrocarbons, occupationally or non-occupationally, is harmful to organisms including human. Several studies tested for toxicity of benzene, toluene and xylene, and interestingly, only a few studies looked into the attenuation. We used Drosophila model to test the genotoxic and apoptotic potential of these compounds and subsequently evaluated the efficiency of two phytochemicals, namely, quercetin and curcumin in attenuating test chemical induced toxicity. We exposed third instar larvae of wild type Drosophila melanogaster (Oregon R+) to 1.0-100.0 mM benzene, toluene or xylene, individually, for 12, 24 and 48 h and examined their apoptotic and genotoxic potential. We observed significantly (P < 0.001) increased apoptotic markers and genotoxicity in a concentration- and time-dependent manner in organisms exposed to benzene, toluene or xylene. We also observed significantly (P < 0.001) increased cytochrome P450 activity in larvae exposed to test chemicals and this was significantly reduced in the presence of 3',4'-dimethoxyflavone, a known Aryl hydrocarbon receptor (AhR) blocker. Interestingly, we observed a significant reduction in cytochrome P450 activity, GST levels, oxidative stress parameters, genotoxic and apoptotic endpoints when organisms were exposed simultaneously to test chemical along with quercetin or curcumin. The study further suggests the suitability of D. melanogaster as an alternate animal model for toxicological studies involving benzene, toluene and xylene and its potential in studying the protective role(s) of phytochemicals.

  7. Metal impurities provide useful tracers for identifying exposures to airborne single-wall carbon nanotubes released from work-related processes

    International Nuclear Information System (INIS)

    This study investigated the use of metal impurities in single-wall carbon nanotubes (SWCNT) as potential tracers to distinguish engineered nanomaterials from background aerosols. TEM and SEM were used to characterize parent material and aerosolized agglomerates collected on PTFE filters using a cascade impactor. SEM image analysis indicated that the SWCNT agglomerates contained about 45% amorphous carbon and backscatter electron analysis indicated that metal impurities were concentrated within the amorphous carbon component. Two elements present as impurities (Y and Ni) were selected as appropriate tracers in this case as their concentrations were found to be highly elevated in the SWCNT parent material (% range) compared to ambient air particles (μg/g range), and background air concentrations were below detection limits for both elements. Bioaccessibility was also determined using physiologically-based extractions at pH conditions relevant to both ingestion and inhalation pathways. A portable wet electrostatic precipitation system effectively captured airborne Y and Ni released during sieving processes, in proportions similar to the bulk sample. These observations support the potential for catalysts and other metal impurities in carbon nanotubes to serve as tracers that uniquely identify emissions at source, after an initial analysis to select appropriate tracers.

  8. Benzene oxygenation and oxidation by the peroxygenase of Agrocybe aegerita.

    Science.gov (United States)

    Karich, Alexander; Kluge, Martin; Ullrich, René; Hofrichter, Martin

    2013-01-01

    Aromatic peroxygenase (APO) is an extracellular enzyme produced by the agaric basidiomycete Agrocybe aegerita that catalyzes diverse peroxide-dependent oxyfunctionalization reactions. Here we describe the oxygenation of the unactivated aromatic ring of benzene with hydrogen peroxide as co-substrate. The optimum pH of the reaction was around 7 and it proceeded via an initial epoxide intermediate that re-aromatized in aqueous solution to form phenol. Identity of the epoxide intermediate as benzene oxide was proved by a freshly prepared authentic standard using GC-MS and LC-MS analyses. Second and third [per]oxygenation was also observed and resulted in the formation of further hydroxylation and following [per]oxidation products: hydroquinone and p-benzoquinone, catechol and o-benzoquinone as well as 1,2,4-trihydroxybenzene and hydroxy-p-benzoquinone, respectively. Using H218O2 as co-substrate and ascorbic acid as radical scavenger, inhibiting the formation of peroxidation products (e.g., p-benzoquinone), the origin of the oxygen atom incorporated into benzene or phenol was proved to be the peroxide. Apparent enzyme kinetic constants (kcat, Km) for the peroxygenation of benzene were estimated to be around 8 s-1 and 3.6 mM. These results raise the possibility that peroxygenases may be useful for enzymatic syntheses of hydroxylated benzene derivatives under mild conditions. PMID:23327645

  9. Aggregation of deuterodichlormethane molecules with benzene molecules. Quantum-chemical calculations and spectroscopic studies

    International Nuclear Information System (INIS)

    C-D vibration band of deuterodichlormethane CD2Cl2 at its low concentration in benzene is slitted into components with frequency 2198 and 2193 cm-1 that is related to formation of weak benzene+deuterodichlormethane complexes. Quantum-chemical calculations confirm a formation of deuterodichlormethane+benzene dimer with participation of benzene's π -electron. Steric factors lead to a difference in orientation of one of deuterium atoms from the central orientation with respect to benzene ring. According to calculations the energy of deuterodichlormethane+benzene dimer is 1.2 kcal/mole. (author)

  10. Occupational Exposure of Petroleum Depot Workers to BTEX Compounds

    Directory of Open Access Journals (Sweden)

    MD Seyedi

    2011-12-01

    Full Text Available Background: Benzene, toluene, ethylbenzene and xylene (BTEX are the most important toxic volatile compounds in the air and could be easily absorbed through the respiratory tract. In recent years, the risk of exposure to BTEX compounds, especially benzene as a carcinogen, has been considered in petroleum depot stations.Objective: To assess the occupational exposure of petroleum depot workers in Iran to BTEX compounds.Methods: After completing a questionnaire and assessing occupational exposure to BTEX compounds, 78 (46 exposed and 32 non-exposed depot workers were randomly selected to participate in this study. Air sampling and analysis of BTEX was conducted according to the NIOSH method No. 1501. Analysis of urinary hippuric acid, as an indicator of toluene exposure, was carried out according to NIOSH method No. 8300. Personal monitoring of the high exposure group to BTEX compounds was repeated to verify the results obtained in the first phase of the monitoring.Results: Among the 9 operating groups studied, occupational exposure to benzene and toluene was higher in quality control and gasoline loading operators—the median exposure ranged from 0.16 to 1.63 ppm for benzene and 0.2 to 2.72 ppm for toluene. Median exposure of other group members to BTEX compounds was below the detection limit of analytical method (0.07, 0.06, 0.05, and 0.05 ppm, respectively. The level of toluene exposure measured showed correlation with neither post-shift urinary hippuric acid (Spearman's rho=0.128, p=0.982 nor with the difference between post- and pre-shift urinary hippuric acid (Spearman's rho=0.089, p=0.847 in depot operational workers.Conclusion: Gasoline loading operators are exposed to a relatively high level of benzene.

  11. Decomposition of benzene in a corona discharge at atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Satoh, Kohki [Department of Electrical and Electronic Engineering, Muroran Institute of Technology, 27-1 Mizumoto, Muroran 050-8585 (Japan); Centre of Environmental Science and Disaster Mitigation for Advanced Research, Muroran Institute of Technology, 27-1 Mizumoto, Muroran 050-8585 (Japan); Matsuzawa, Toshiharu; Itoh, Hidenori [Department of Electrical and Electronic Engineering, Muroran Institute of Technology, 27-1 Mizumoto, Muroran 050-8585 (Japan)

    2008-05-01

    We investigated the decomposition characteristics of benzene in a positive DC corona discharge between multineedle and plane electrodes with a background gas of nitrogen-oxygen mixture at atmospheric pressure. We obtained C{sub 2}H{sub 2}, HCN, HCOOH, CO and CO{sub 2} as benzene fragments and by-products, and C{sub 2}H{sub 2} and HCN as minor intermediate products. Benzene was primarily converted into CO{sub 2} via CO at low oxygen concentrations (0.2%) and via CO and HCOOH at the atmospheric oxygen concentration (20%). Further, 57% and 24% of carbon atoms were deposited on the plane electrode and the discharge chamber at oxygen concentrations of 0.2% and 20%, respectively.

  12. Comparative Analysis between Conventional PI and Fuzzy LogicPI Controllers for Indoor Benzene Concentrations

    Directory of Open Access Journals (Sweden)

    Nun Pitalúa-Díaz

    2015-05-01

    Full Text Available Exposure to hazardous concentrations of volatile organic compounds indoors in small workshops could affect the health of workers, resulting in respirative diseases, severe intoxication or even cancer. Controlling the concentration of volatile organic compounds is required to prevent harmful conditions for workers in indoor environments. In this document, PI and fuzzy PI controllers were used to reduce hazardous indoor air benzene concentrations in small workplaces. The workshop is represented by means of a well-mixed room model. From the knowledge obtained from the model, PI and fuzzy PI controllers were designed and their performances were compared. Both controllers were able to maintain the benzene concentration within secure levels for the workers. The fuzzy PI controller performed more efficiently than the PI controller. Both approaches could be expanded to control multiple extractor fans in order to reduce the air pollution in a shorter time. The results from the comparative analysis showed that implementing a fuzzy logic PI controller is promising for assuring indoor air quality in this kind of hazardous work environment.

  13. Benzene/nitrous oxide flammability in the precipitate hydrolysis process

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, R A [Du Pont de Nemours (E.I.) and Co., Aiken, SC (USA). Savannah River Lab.

    1989-09-18

    The HAN (hydroxylamine nitrate) process for destruction of nitrite in precipitate hydrolysis produces nitrous oxide (N2O) gas as one of the products. N2O can form flammable mixtures with benzene which is also present due to radiolysis and hydrolysis of tetraphenylborate. Extensive flame modeling and explosion testing was undertaken to define the minimum oxidant for combustion of N2O/benzene using both nitrogen and carbon dioxide as diluents. The attached memorandum interprets and documents the results of the studies.

  14. Oxidation of benzene by radiolytically produced OH radicals

    International Nuclear Information System (INIS)

    The radiolysis of N2O saturated-aqueous solutions of benzene-14C has been examined using radio-liquid chromatographic methods to follow the quantitative aspects of the reactions of hydroxycyclohexadienyl radicals. In the absence of a radical oxidant, at least five important products are produced. The total yield of 5.8 observed for the incorporation of benzene into products accounts for essentially all of the radicals initially produced from the water. Dimeric products predominate with a total yield of 4.1. Phenol is produced with a yield of only 0.8 indicating a disproportionation/ combination ratio for hydroxycyclohexadienyl radicals of 2O saturated aqueous solutions. (author)

  15. Electronic Conductivity of Polypyrrole−Dodecyl Benzene Sulfonate Complexes

    DEFF Research Database (Denmark)

    West, Keld; Bay, Lasse; Nielsen, Martin Meedom;

    2004-01-01

    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...... dodecyl isomers (with the benzene group at positions 1, 2 and 6). The conductivity was measured both by van der Pauw measurements on PPy-DBS in the oxidized, dry state as function of temperature, and by electrochemical impedance spectroscopy as function of potential in 0.1 M NaCl aqueous electrolyte...

  16. The past suppression of industry knowledge of the toxicity of benzene to humans and potential bias in future benzene research.

    Science.gov (United States)

    Infante, Peter F

    2006-01-01

    Petrochemical industry representatives often withhold information and misinterpret positive evidence of toxicity of benzene, even from their own research, also discouraging or delaying disclosure of findings of adverse effects to the public. They now appear to be attempting to influence study results in industry's favor by offering predetermined conclusions about study results as part of an effort to draw financial support for the studies. The American Petroleum Institute is currently raising funds for benzene research being conducted in China for which it has already announced the intended conclusions. PMID:16967835

  17. Hydroxylation and Carboxylation—Two Crucial Steps of Anaerobic Benzene Degradation by Dechloromonas Strain RCB

    OpenAIRE

    Chakraborty, Romy; Coates, John D.

    2005-01-01

    Benzene is a highly toxic industrial compound that is essential to the production of various chemicals, drugs, and fuel oils. Due to its toxicity and carcinogenicity, much recent attention has been focused on benzene biodegradation, especially in the absence of molecular oxygen. However, the mechanism by which anaerobic benzene biodegradation occurs is still unclear. This is because until the recent isolation of Dechloromonas strains JJ and RCB no organism that anaerobically degraded benzene ...

  18. Are there Efimov trimers in hexafluorobenzene rather than in benzene vapor itself?

    International Nuclear Information System (INIS)

    Is there a spectroscopic method to detect an Efimov state? Following our proposal of an Efimov state arising from three pseudo bosons (generalized Cooper pairs) in benzene, our spectroscopic studies have found no evidence of Efimov trimers (ET) in h6- or d6-benzene. However, hexafluoro-benzene has shown peaks that we attributed to ET and the pseudo bosons. The experimental evidence suggests that benzene pseudo bosons and subsequently ET are quite sensitive to the surroundings

  19. Electrochemical study of benzene on Pt of various surface structures in alkaline and acidic solutions

    OpenAIRE

    Montilla Jiménez, Francisco; Morallón Núñez, Emilia; Vázquez Picó, José Luis

    2002-01-01

    The electrochemical behaviour of benzene on platinum electrodes (polycrystalline and single-crystal electrodes) has been studied in acidic and alkaline solutions. In acid solutions the reduction of benzene to cyclohexane takes place in all the platinum surface structure employed, however it does not occur in alkaline media (0.1 M NaOH). In this case, the hydrogen adsorption/desorption processes displace the adsorbed benzene from the electrode surface. The oxidation of benzene is also af...

  20. Traffic-related air pollution and the onset of myocardial infarction: disclosing benzene as a trigger? A small-area case-crossover study.

    Directory of Open Access Journals (Sweden)

    Denis Bard

    Full Text Available Exposure to traffic is an established risk factor for the triggering of myocardial infarction (MI. Particulate matter, mainly emitted by diesel vehicles, appears to be the most important stressor. However, the possible influence of benzene from gasoline-fueled cars has not been explored so far.We conducted a case-crossover study from 2,134 MI cases recorded by the local Coronary Heart Disease Registry (2000-2007 in the Strasbourg Metropolitan Area (France. Available individual data were age, gender, previous history of ischemic heart disease and address of residence at the time of the event. Nitrogen dioxide, particles of median aerodynamic diameter <10 µm (PM10, ozone, carbon monoxide and benzene air concentrations were modeled on an hourly basis at the census block level over the study period using the deterministic ADMS-Urban air dispersion model. Model input data were emissions inventories, background pollution measurements, and meteorological data. We have found a positive, statistically significant association between concentrations of benzene and the onset of MI: per cent increase in risk for a 1 µg/m3 increase in benzene concentration in the previous 0, 0-1 and 1 day was 10.4 (95% confidence interval 3-18.2, 10.7 (2.7-19.2 and 7.2 (0.3-14.5, respectively. The associations between the other pollutants and outcome were much lower and in accordance with the literature.We have observed that benzene in ambient air is strongly associated with the triggering of MI. This novel finding needs confirmation. If so, this would mean that not only diesel vehicles, the main particulate matter emitters, but also gasoline-fueled cars--main benzene emitters-, should be taken into account for public health action.

  1. A short-term test adapted to detect the genotoxic effects of environmental volatile pollutants (benzene fumes) using the filamentous fungus Aspergillus nidulans.

    Science.gov (United States)

    Domingues Zucchi, Tiago; Domingues Zucchi, Fernando; Poli, Paola; Soares de Melo, Itamar; Zucchi, Tania M A D

    2005-06-01

    With the recent focus on environmental problems, increasing awareness of the harmful effects of industrial and agricultural pollution has created a demand for progressively more sophisticated pollutant and toxicity detection methods. Using Aspergillus nidulans strains this work presents a new short term-test that, most importantly, enables the rapid and inexpensive detection of volatile pollutants that induce genotoxic/carcinogenic effects in animals. The main aim is to contribute to environmental health protection, and special attention is directed to monitoring the hazard posed by benzene (as a carcinogenic agent model) mainly because its ubiquitous presence often leads to severe noxious effects in humans among whom increased rates of human leukemia have been reported. To evaluate even the submutagenic effects of benzene fumes, two Aspergillus nidulans diploid strains, heterozygous for several auxotrophic mutations, were used. The DNA lesions produced stimulate mitotic recombination and homozygotization of auxotrophic recessive mutations. Conidial exposure to a saturated atmosphere of benzene fumes for 20 s was enough to increase the mitotic recombination frequencies significantly. Genetic analyses of treated diploids evidenced alterations related to mitotic recombination frequencies, gene expression, and allelic segregation rates. Altogether they reflect the potential of benzene to induce alterations in the fungal DNA, and albeit indirectly, they also respond for the genotoxic/carcinogenic harmful side effects widely connected to benzene. This is the first description of a sensitive, rapid and inexpensive test able to detect the submutagenic dose effects of volatile environmental compounds. In addition, despite concentrating on benzene the same test can be applied to many other pollutants, volatile or not. Additionally, the test can also be used to detect the antigenotoxic properties of foods and drugs. PMID:15931421

  2. Carcinogenic Effects of Benzene: An Update (1997 External Review Draft)

    Science.gov (United States)

    In 1992, the U.S. Environmental Protection Agency's (EPA's) Office of Mobile Sources (OMS) requested the National Center for Environmental Assessment (NCEA) to provide an updated characterization of the cancer risk of benzene to humans. The previous characterization of the carcin...

  3. Instrument for benzene and toluene emission measurements of glycol regenerators

    International Nuclear Information System (INIS)

    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)

  4. 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 soi

  5. Extraction of cadmium thiocyanate complex by tributyl phosphate in benzene

    Energy Technology Data Exchange (ETDEWEB)

    Singh, D.; Tandon, S.N. (Roorkee Univ. (India). Dept. of Chemistry)

    1981-09-01

    The extraction of cadmium thiocyanate complex has been studied in benzene solution of tri-n-butyl phosphate. The species extracted is shown to be Cd(SCN)X.4TBP, where X is a common anion. The extraction data have also been used for achieving some metal ion separation.

  6. Selective Oxidation of Benzene to Phenol. Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Sherif, F.; Kung, H.; Marshall, C.

    2000-09-30

    Direct catalytic oxidation of commodity aromatics to phenolic compounds was studied by a team from Akzo Nobel Chemicals, Argonne National Lab., and Northwestern University. Results did not exceed previously published performance. The object of the project was to selectively oxidize benzene to phenol using a conventional oxidant.

  7. 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...

  8. 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...

  9. 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—...

  10. 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...

  11. 40 CFR 80.1290 - How are standard benzene credits generated?

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false How are standard benzene credits... PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Benzene Averaging, Banking and Trading (abt) Program § 80.1290 How are standard benzene credits generated? (a) The standard credit...

  12. 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),...

  13. 40 CFR 80.1275 - How are early benzene credits generated?

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false How are early benzene credits... PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Benzene Averaging, Banking and Trading (abt) Program § 80.1275 How are early benzene credits generated? (a) For each averaging period...

  14. 40 CFR 80.1235 - What gasoline is subject to the benzene requirements of this subpart?

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false What gasoline is subject to the... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) REGULATION OF FUELS AND FUEL ADDITIVES Gasoline Benzene Gasoline Benzene Requirements § 80.1235 What gasoline is subject to the benzene requirements...

  15. 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.

  16. 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

    2015-06-01

    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

  17. Modeling annual benzene, toluene, NO2, and soot concentrations on the basis of road traffic characteristics

    International Nuclear Information System (INIS)

    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, NO2, 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, NO2, and soot from 18 high-concentration sites means: 8.7, 65.8, and 12.9 μg/m3, respectively) and from 16 school sites with moderate concentrations (means: 2.6, 32.2, and 5.7 μg/m3, 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 (R2: 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

  18. Inhibitory effect of benzene metabolites on nuclear DNA synthesis in bone marrow cells

    International Nuclear Information System (INIS)

    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 [3H]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 [3H]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

  19. Use of radiation sources with mercury isotopes for real-time highly sensitive and selective benzene determination in air and natural gas by differential absorption spectrometry with the direct Zeeman effect.

    Science.gov (United States)

    Revalde, Gita; Sholupov, Sergey; Ganeev, Alexander; Pogarev, Sergey; Ryzhov, Vladimir; Skudra, Atis

    2015-08-01

    A new analytical portable system is proposed for the direct determination of benzene vapor in the ambient air and natural gas, using differential absorption spectrometry with the direct Zeeman effect and innovative radiation sources: capillary mercury lamps with different isotopic compositions ((196)Hg, (198)Hg, (202)Hg, (204)Hg, and natural isotopic mixture). Resonance emission of mercury at a wavelength of 254 nm is used as probing radiation. The differential cross section of benzene absorption in dependence on wavelength is determined by scanning of magnetic field. It is found that the sensitivity of benzene detection is enhanced three times using lamp with the mercury isotope (204)Hg in comparison with lamp, filled with the natural isotopic mixture. It is experimentally demonstrated that, when benzene content is measured at the Occupational Exposure Limit (3.2 mg/m(3) for benzene) level, the interference from SO2, NO2, O3, H2S and toluene can be neglected if concentration of these gases does not exceed corresponding Occupational Exposure Limits. To exclude the mercury effect, filters that absorb mercury and let benzene pass in the gas duct are proposed. Basing on the results of our study, a portable spectrometer is designed with a multipath cell of 960 cm total path length and detection limit 0.5 mg/m(3) at 1 s averaging and 0.1 mg/m(3) at 30 s averaging. The applications of the designed spectrometer to measuring the benzene concentration in the atmospheric air from a moving vehicle and in natural gas are exemplified. PMID:26320799

  20. Indoor exposure and adverse birth outcomes related to fetal growth, miscarriage and prematurity-a systematic review.

    Science.gov (United States)

    Patelarou, Evridiki; Kelly, Frank J

    2014-06-01

    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. PMID:24896737

  1. 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.

  2. Use of radiation sources with mercury isotopes for real-time highly sensitive and selective benzene determination in air and natural gas by differential absorption spectrometry with the direct Zeeman effect

    International Nuclear Information System (INIS)

    A new analytical portable system is proposed for the direct determination of benzene vapor in the ambient air and natural gas, using differential absorption spectrometry with the direct Zeeman effect and innovative radiation sources: capillary mercury lamps with different isotopic compositions (196Hg, 198Hg, 202Hg, 204Hg, and natural isotopic mixture). Resonance emission of mercury at a wavelength of 254 nm is used as probing radiation. The differential cross section of benzene absorption in dependence on wavelength is determined by scanning of magnetic field. It is found that the sensitivity of benzene detection is enhanced three times using lamp with the mercury isotope 204Hg in comparison with lamp, filled with the natural isotopic mixture. It is experimentally demonstrated that, when benzene content is measured at the Occupational Exposure Limit (3.2 mg/m3 for benzene) level, the interference from SO2, NO2, O3, H2S and toluene can be neglected if concentration of these gases does not exceed corresponding Occupational Exposure Limits. To exclude the mercury effect, filters that absorb mercury and let benzene pass in the gas duct are proposed. Basing on the results of our study, a portable spectrometer is designed with a multipath cell of 960 cm total path length and detection limit 0.5 mg/m3 at 1 s averaging and 0.1 mg/m3 at 30 s averaging. The applications of the designed spectrometer to measuring the benzene concentration in the atmospheric air from a moving vehicle and in natural gas are exemplified. - Highlights: • Portable benzene analyser is designed for direct benzene detection in air and gas. • Zeeman effect absorption spectrometry ensures very low benzene detection limits. • The Hg 2537 nm emission line from capillary mercury lamp is used for absorption. • The best sensitivity and selectivity is found using Hg 204 isotope light source. • Mercury influence is eliminated by using a sorption filter at the inlet

  3. Use of radiation sources with mercury isotopes for real-time highly sensitive and selective benzene determination in air and natural gas by differential absorption spectrometry with the direct Zeeman effect

    Energy Technology Data Exchange (ETDEWEB)

    Revalde, Gita, E-mail: gitar@latnet.lv [Institute of Technical Physics, Riga Technical University, P.Valdena 3, Riga LV 1050 (Latvia); Sholupov, Sergey; Ganeev, Alexander; Pogarev, Sergey; Ryzhov, Vladimir [St. Petersburg State University, Universitetskaya nab., 7/9, St. Petersburg 199034 (Russian Federation); Skudra, Atis [Institute of Atomic Physics and Spectroscopy, University of Latvia, Skunu 4, Riga (Latvia)

    2015-08-05

    A new analytical portable system is proposed for the direct determination of benzene vapor in the ambient air and natural gas, using differential absorption spectrometry with the direct Zeeman effect and innovative radiation sources: capillary mercury lamps with different isotopic compositions ({sup 196}Hg, {sup 198}Hg, {sup 202}Hg, {sup 204}Hg, and natural isotopic mixture). Resonance emission of mercury at a wavelength of 254 nm is used as probing radiation. The differential cross section of benzene absorption in dependence on wavelength is determined by scanning of magnetic field. It is found that the sensitivity of benzene detection is enhanced three times using lamp with the mercury isotope {sup 204}Hg in comparison with lamp, filled with the natural isotopic mixture. It is experimentally demonstrated that, when benzene content is measured at the Occupational Exposure Limit (3.2 mg/m{sup 3} for benzene) level, the interference from SO{sub 2}, NO{sub 2}, O{sub 3}, H{sub 2}S and toluene can be neglected if concentration of these gases does not exceed corresponding Occupational Exposure Limits. To exclude the mercury effect, filters that absorb mercury and let benzene pass in the gas duct are proposed. Basing on the results of our study, a portable spectrometer is designed with a multipath cell of 960 cm total path length and detection limit 0.5 mg/m{sup 3} at 1 s averaging and 0.1 mg/m{sup 3} at 30 s averaging. The applications of the designed spectrometer to measuring the benzene concentration in the atmospheric air from a moving vehicle and in natural gas are exemplified. - Highlights: • Portable benzene analyser is designed for direct benzene detection in air and gas. • Zeeman effect absorption spectrometry ensures very low benzene detection limits. • The Hg 2537 nm emission line from capillary mercury lamp is used for absorption. • The best sensitivity and selectivity is found using Hg 204 isotope light source. • Mercury influence is

  4. 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)

  5. Synthesis and nucleophilic aromatic substitution of 3-fluoro-5-nitro-1-(pentafluorosulfanyl)benzene.

    Science.gov (United States)

    Ajenjo, Javier; Greenhall, Martin; Zarantonello, Camillo; Beier, Petr

    2016-01-01

    3-Fluoro-5-nitro-1-(pentafluorosulfanyl)benzene was prepared by three different ways: as a byproduct of direct fluorination of 1,2-bis(3-nitrophenyl)disulfane, by direct fluorination of 4-nitro-1-(pentafluorosulfanyl)benzene, and by fluorodenitration of 3,5-dinitro-1-(pentafluorosulfanyl)benzene. The title compound was subjected to a nucleophilic aromatic substitution of the fluorine atom with oxygen, sulfur and nitrogen nucleophiles affording novel (pentafluorosulfanyl)benzenes with 3,5-disubstitution pattern. Vicarious nucleophilic substitution of the title compound with carbon, oxygen, and nitrogen nucleophiles provided 3-fluoro-5-nitro-1-(pentafluorosulfanyl)benzenes substituted in position four. PMID:26977178

  6. The Grand Canonical Monte Carlo Simulations of Benzene and Propylene in ITQ-1 Zeolite

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Grand Canonical Monte Carlo (GCMC) simulations have been performed to study the localization and adsorption behavior of benzene and propylene, in purely siliceous MWW zeolite (ITQ-1). By analyzing the locations of benzene and propylene in ITQ-1, it can be deduced that the alkylation of benzene and propylene will mainly happen in 12-MR supercages at the external surface or close to the external surface. The adsorption isotherms of benzene and propylene at 315K and 0~3.5kPa are predicted, and the results for benzene generally coincide with the trend from the experiments of a series of aromatic compounds.

  7. 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...... phase of transformation. The microorganisms were able to transform thiophene in the absence of benzene at a zero-order rate. Thiophene was converted to five oxidation products, regardless of the presence of benzene. Benzene had no influence on the distribution of these oxidation products. The main...

  8. Benzene activates caspase-4 and -12 at the transcription level, without an association with apoptosis, in mouse bone marrow cells lacking the p53 gene

    Energy Technology Data Exchange (ETDEWEB)

    Yi, Jung-Yeon; Han, Jeong-Hee; Yoon, Byung-Il [Kangwon National University, School of Veterinary Medicine, Chuncheon, Gangwon (Korea); Hirabayashi, Yoko; Kodama, Yukio; Kanno, Jun [National Institute of Health Sciences, Division of Cellular and Molecular Toxicology, Center for Biological Safety and Research, Tokyo (Japan); Choi, Yang-Kyu [Konkuk University, College of Veterinary Medicine, Seoul (Korea); Inoue, Tohru [National Institute of Health Sciences, Biological Safety and Research Center, Tokyo (Japan)

    2009-08-15

    Benzene is a well-known environmental pollutant that can induce hematotoxicity, aplastic anemia, acute myelogenous leukemia, and lymphoma. However, although benzene metabolites are known to induce oxidative stress and disrupt the cell cycle, the mechanism underlying lympho/leukemogenicity is not fully understood. Caspase-4 (alias caspase-11) and -12 are inflammatory caspases implicated in inflammation and endoplasmic reticulum stress-induced apoptosis. The objectives of this study were to investigate the altered expression of caspase-4 and -12 in mouse bone marrow after benzene exposure and to determine whether their alterations are associated with benzene-induced bone marrow toxicity, especially cellular apoptosis. In addition, we evaluated whether the p53 gene is involved in regulating the mechanism, using both wild-type (WT) mice and mice lacking the p53 gene. For this study, 8-week-old C57BL/6 mice [WT and p53 knockout (KO)] were administered a benzene solution (150 mg/kg diluted in corn oil) via oral gavage once daily, 5 days/week, for 1 or 2 weeks. Blood and bone marrow cells were collected and cell counts were measured using a Coulter counter. Total mRNA and protein extracts were prepared from the harvested bone marrow cells. Then qRT-PCR and Western blotting were performed to detect changes in the caspases at the mRNA and protein level, respectively. A DNA fragmentation assay and Annexin-V staining were carried out on the bone marrow cells to detect apoptosis. Results indicated that when compared to the control, leukocyte number and bone marrow cellularity decreased significantly in WT mice. The expression of caspase-4 and -12 mRNA increased significantly after 12 days of benzene treatment in the bone marrow cells of benzene-exposed p53KO mice. However, apoptosis detection assays indicated no evidence of apoptosis in p53KO or WT mice. In addition, no changes of other apoptosis-related caspases, such as caspase-3 and -9, were found in WT or p53KO mice at the

  9. GC/MS analyses of fractionated extraction of Shenfu coal with CS2, n-hexane, benzene

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-hua; WEI Xian-yong

    2008-01-01

    Shenfu coal was extracted with CS2,n-hexane,benzene sequentially.The extracts were analyzed with GC/MS.It is presented that group seperation of soluble organic compounds in the coal can be achieved by fractionated extraction using different solvents.Main components in CS2 soluble fraction from Shenfu coal are alkyl-substituted arenes.Aliphatic hydrocarbons are overwhelmingly predominant in n-hexane-soluble fraction.Dito tricyclic aramatic hydrocarbons are identified in benzene-soluble fraction.The molecular structures detection of 2,4,6-trichlorobenzenamine and 3,3',4,4',5,5'-hexachloro-1,1'-biphenyl and 2-chiorocyclohexanol firstly provide information for existence form of chlorine in coal.

  10. Inhalation exposure or body burden? Better way of estimating risk--An application of PBPK model.

    Science.gov (United States)

    Majumdar, Dipanjali; Dutta, Chirasree; Sen, Subha

    2016-01-01

    We aim to establish a new way for estimating the risk from internal dose or body burden due to exposure of benzene in human subject utilizing physiologically based pharmacokinetic (PBPK) model. We also intend to verify its applicability on human subjects exposed to different levels of benzene. We estimated personal inhalation exposure of benzene for two occupational groups namely petrol pump workers and car drivers with respect to a control group, only environmentally exposed. Benzene in personal air was pre-concentrated on charcoal followed by chemical desorption and analysis by gas chromatography equipped with flame ionization detector (GC-FID). We selected urinary trans,trans-muconic acid (t,t-MA) as biomarker of benzene exposure and measured its concentration using solid phase extraction followed by high performance liquid chromatography (HPLC). Our estimated inhalation exposure of benzene was 137.5, 97.9 and 38.7 μg/m(3) for petrol pump workers, car drivers and environmentally exposed control groups respectively which resulted in urinary t,t-MA levels of 145.4±55.3, 112.6±63.5 and 60.0±34.9 μg g(-1) of creatinine, for the groups in the same order. We deduced a derivation for estimation of body burden from urinary metabolite concentration using PBPK model. Estimation of the internal dose or body burden of benzene in human subject has been made for the first time by the measurement of t,t-MA as a urinary metabolite using physiologically based pharmacokinetic (PBPK) model as a tool. The weight adjusted total body burden of benzene was estimated to be 17.6, 11.1 and 5.0 μg kg(-1) of body weight for petrol pump workers, drivers and the environmentally exposed control group, respectively using this method. We computed the carcinogenic risk using both the estimated internal benzene body burden and external exposure values using conventional method. Our study result shows that internal dose or body burden is not proportional to level of exposure rather have a

  11. In-situ Investigation of BBr_3/benzene Solution by Fourier Transformation Infrared Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    YU Li-li; GAI Li-gang; CUI De-Hang; WANG Qi-long

    2009-01-01

    By means of the in-situ Fourier transformation infrared spectroscopy(FTIR), the properties of BBr_3/ benzene solution, which is usually used as the reactant and solution to synthesize BN by benzene-thermal method, have been investigated. The results show that there are some side reactions between BBr_3 and benzene: (1) BBr_3 as an electron-deficient molecule reacts with benzene at room temperature; (2) below 100℃, substitution of Br atom for H atom of benzene(ring-H) dominates in BBr_3/benzene solution; (3) cracking of benzene ring occurs at a temperature above 100℃; (4) decomposition of benzene molecules and formation of long-chain aliphatic compounds feature the spectra of BBr_3/benzene solution collected at above 160℃. They are unfavor for BN to form when BBr_3 is excessive in the synthesis of BN by benzene-thermal route. On the basis of the experimental results, a coordination reaction mechanism via a η~2-C_6H_6 binding mode in BBr_3/benzene solution is suggested.

  12. Experimental study of removing benzene from indoor air by needle-matrix to plate streamer discharge

    International Nuclear Information System (INIS)

    The degradation of benzene by needle-matrix to plate streamer discharge was investigated at normal temperature and pressure in indoor air. The effects of benzene initial concentration, air speed, discharge power and relative humidity (RH) on benzene removal rate were systematically studied. Meanwhile, the benzene removal efficiencies by adding MnO2/SiO2-active carbon catalyst to the system were also studied. The results showed that the benzene removal rate increased with the rise of the air speed and discharge power, decreased with the rise of the benzene initial concentration, and firstly increased and then decreased with the rise of the of RH. Under the same experimental conditions, adding MnO2 catalyst to the system did not significantly improve the removal efficiency of benzene.

  13. 40 CFR 80.1240 - How is a refinery's or importer's compliance with the gasoline benzene requirements of this...

    Science.gov (United States)

    2010-07-01

    ... compliance with the gasoline benzene requirements of this subpart determined? 80.1240 Section 80.1240... FUELS AND FUEL ADDITIVES Gasoline Benzene Gasoline Benzene Requirements § 80.1240 How is a refinery's or importer's compliance with the gasoline benzene requirements of this subpart determined? (a) A...

  14. 40 CFR 80.1334 - What are the requirements for early compliance with the gasoline benzene program?

    Science.gov (United States)

    2010-07-01

    ... compliance with the gasoline benzene program? 80.1334 Section 80.1334 Protection of Environment ENVIRONMENTAL... Benzene Hardship Provisions § 80.1334 What are the requirements for early compliance with the gasoline benzene program? (a)(1) A refinery may comply with the benzene requirements at § 80.1230 for its RFG...

  15. The Alberta Oil Sands Community Exposure and Health Effects Assessment Program : methods report

    International Nuclear Information System (INIS)

    The Alberta Oil Sands Community Exposure and Health Effects Assessment Program involved the development of a holistic approach to the study of personal exposure and the potential health impacts of airborne contaminants including volatile organic compounds (VOCs), sulphur dioxide (SO2), nitrogen dioxide (NO2), ozone (O3) and particulates (both PM10 and PM2.5). Volunteer residents from Fort McMurray, Alberta were recruited to participate in neurocognitive tests and a health and nutrition survey. In addition, the local community identified several priority contaminants which were highlighted during a public hearing of the Alberta Energy and Utilities Board in relation to Syncrude's Mildred Lake Development Project. The approach to the study was based on the direct measurement of all routes of exposure to the contaminants (breathing, ingestion and skin contact), direct measurement of biomarkers, and daily logs of participant's activities. The choice of biomarkers was based on the ability of the laboratory to measure low levels of relevant biological markers, the most appropriate media for measuring the markers, and the burden placed on each volunteer. The final set of biological measures of exposure included trace metals (arsenic, cadmium, lead and uranium) nicotine, and metabolites of the BTEX compounds (benzene, toluene, ethylbenzene, and xylenes). The objective was to determine if chronic or occupational exposure to these contaminants cause structural alterations in the respiratory system that compromise oxygen absorption and lung elasticity. 82 refs., 14 tabs., 15 figs., 3 appendices

  16. Thermodynamics of mixtures involving some (benzene derivatives+benzonitrile)

    International Nuclear Information System (INIS)

    Interactions of binary mixtures involving some benzene derivatives (ethylbenzene, o-, m-, p-xylene, isopropylbenzene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, and methoxybenzene) with benzonitrile were investigated in continuation of our previous studies on binary systems (benzene or toluene+benzonitrile). Heat capacities by volume unit, determined with a Picker flow calorimeter at T=298.15K, and densities, measured by using Picker vibrating densimeters at the temperatures (298.15 and 308.15)K, are reported. Measurements were made over the entire range of mole fraction. From the primary measurements, the corresponding excess quantities VE and Cp,mE are obtained. The magnitude of these experimental quantities together with HE literature data is discussed in terms of the nature and type of intermolecular interactions in binary mixtures

  17. Molecular Dynamics Investigation of Benzene in Supercritical Water

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Microscopic structure and diffusion properties of benzene in ambient water (298 K, 0.1 MPa) and super critical water (673-773 K, 25-35 MPa) are investigated by molecular dynamics simulation with site-site models. It is found that at the ambient condition, the water molecules surrounding a benzene molecule form a hydrogen bond network. The hydrogen bond interaction between supercritical water molecules decreases dramatically under supercritical conditions. The diffusion coefficients of both the solute molecule and solvent molecule at supercritical conditions increase by 30-180 times than those at the ambient condition. With the temperature approaching the critical temperature, the change of diffusion coefficient with pressure becomes pronounced.

  18. Benzene leaks in sight; Benzeenlekken in het vizier

    Energy Technology Data Exchange (ETDEWEB)

    Okkerse, W.J.; Van Doorn, R.; Bison, H. [DCMR Milieudienst Rijnmond, Rotterdam (Netherlands)

    2013-02-15

    About five years ago, elevated concentrations of benzene were detected at air measuring stations of the DCMR Environmental Protection Agency in the Botlek area, the Netherlands. Extensive research of potential sources in industry followed. A wide range of advanced techniques were deployed. A smart combination of techniques has ultimately resulted in the identification and clean-up of the benzene sources. A bright future is anticipated for these techniques [Dutch] Ongeveer vijf jaar geleden werden rond het Botlekgebied verhoogde benzeenconcentraties geconstateerd op luchtmeetstations van de DCMR Milieudienst Rijnmond. Een uitgebreid onderzoek naar de potentiele bronnen in de industrie was het gevolg. Daarbij is een scala aan geavanceerde technieken ingezet. Toepassing van een slimme combinatie van technieken heeft er uiteindelijk toe geleid dat benzeenbronnen werden opgespoord en gesaneerd. Een grote toekomst wordt voorzien voor deze technieken.

  19. 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.

  20. Atomic Structure of Benzene Which Accounts for Resonance Energy

    OpenAIRE

    Heyrovska, Raji

    2008-01-01

    Benzene is a hexagonal molecule of six carbon atoms, each of which is bound to six hydrogen atoms. The equality of all six CC bond lengths, despite the alternating double and single bonds, and the surplus (resonance) energy, led to the suggestion of two resonanting structures. Here, the new atomic structure shows that the bond length equality is due to three carbon atoms with double bond radii bound to three other carbon atoms with resonance bond radii (as in graphene). Consequently, there ar...

  1. Degradation of benzene and other aromatic hydrocarbons by anaerobic bacteria

    OpenAIRE

    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 soils, sediments and groundwater. The mobility and toxicity of the BTEX compounds are of major concern. In situ bioremediation of BTEX by using naturally occurring microorganisms or introduced microor...

  2. ADSORPTION OF WATER AND BENZENE VAPOUR IN MESOPOROUS MATERIALS

    OpenAIRE

    Paulina Taba

    2008-01-01

    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 cethyltrimethylammoniu...

  3. Pure Benzene Will Be Serous Short of Supply

    Institute of Scientific and Technical Information of China (English)

    John Zheng

    2007-01-01

    @@ Benzene is one of the important ba-sic raw materials for petrochemicals.It can be used to synthesize a seriesof important chemical products suchas synthetic rubbers, synthetic resins,synthetic fibers, pharmaceuticals,pesticides, explosives and dyestuffs.It can also be used as a solvent forcoatings and rubbers and as a blend-ing agent to increase gasoline's oc-tane number in the refining sector.

  4. LED Irradiation of a Photocatalyst for Benzene, Toluene, Ethyl Benzene,and Xylene Decomposition%LED Irradiation of a Photocatalyst for Benzene,Toluene,Ethyl Benzene,and Xylene Decomposition

    Institute of Scientific and Technical Information of China (English)

    JO Wan-Kuen; KANG Hyun-Jung

    2012-01-01

    Studies on the use of gas phase applications of light emitting diodes (LEDs) in photocatalysis are scarce although their photocatalytic decomposition kinetics of environmental pollutants are likely different from those in aqueous solutions.The present study evaluated the use of chips of visible light LEDs to irradiate nitrogen doped titania (N-TiO2) prepared by hydrolysis to decompose gaseous benzene,toluene,ethyl benzene,m-xylene,p-xylene,and o-xylene.Photocatalysts calcined at different temperatures were characterized by various analytical instruments.The degradation efficiency of benzene was close to zero for all conditions.For the other compounds,a conventional 8 W daylight lamp/N-TiO2 unit gave a higher photocatalytic degradation efficiency as compared with that of visible-LED/N-TiO2 units.However,the ratios of degradation efficiency to electric power consumption were higher for the photocatalytic units that used two types of visible-LED lamps (blue and white LEDs).The highest degradation efficiency was observed with the use of a calcination temperature of 350 ℃.The average degradation efficiencies for toluene,ethyl benzene,m-xylene,p-xylene,and o-xylene were 35%,68%,94%,and 93%,respectively.The use of blue-and white-LEDs,high light intensity,and low initial concentrations gave high photocatalytic activities for the photocatalytic units using visible-LEDs.The morphological and optical properties of the photocatalysts were correlated to explain the dependence of photocatalytic activity on calcination temperature.The results suggest that visible-LEDs are energy efficient light source for photocatalytic gas phase applications,but the activity depends on the operational conditions.

  5. 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.

  6. Dissociative electron attachment to laser-excited benzene

    International Nuclear Information System (INIS)

    We have conducted comprehensive measurements on enhanced electron attachment to ArF and KrF laser-excited benzene in the presence of Ar and N2 buffer gases. At both these laser lines, two-photon absorption leads to excitation of benzene to energies above its ionization potential. Such excitations have been shown to lead to a population of long-lived, core-excited high-Rydberg states in addition to the ionization of the molecule. Present measurements on the dependence of negative ion yield on laser fluence, benzene pressure, and applied electric field verify that the observed negative ion formation is due to the attachment of the photoelectrons to the concomitantly produced high-Rydberg states. Using a rate equation analysis, the electron attachment rate constant for the core-excited Rydberg states was estimated to be of the order of 10-4-10-3 cm3 s-1. Laser photoionization cross sections were also estimated, and the cross section at the KrF laser line is in agreement (author)

  7. 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.

  8. Methane from benzene in argon dielectric barrier discharge

    International Nuclear Information System (INIS)

    Highlights: ► Efficient on-line conversion of benzene to methane at room temperature. ► Absence of other H-atom donor suggests new type of chemistry. ► For parent loss > 90%, methane yield was ∼40% of limit due to H-atom availability. ► Surface moisture contributed ·OH radical for trace phenolic products’ formation. ► This method may emerge as an exploitable tactic for pollutants’ usable alterations. -- Abstract: A first-time account of direct, on-line, instantaneous and efficient chemical conversion of gas phase benzene to methane in argon Dielectric Barrier Discharge (DBD) is presented. In the absence of another overt hydrogen-donating source, potency of analogous parents toward methane generation is found to follow the order: benzene > toluene > p-xylene. Simultaneous production of trace amounts of phenolic surface deposits suggest (a) prompt decomposition of the parent molecules, including a large fraction yielding atomic transients (H-atom), (b) continuous and appropriate recombination of such parts, and (c) trace moisture in parent contributing ·OH radicals and additional H-atoms, which suitably react with the unreacted fraction of the parent, and also other intermediates. Results highlight Ar DBD to be a simple and exploitable technology for transforming undesirable hazardous aromatics to usable/useful low molecular weight open-chain products following the principles of green chemistry and engineering

  9. Adsorption of trichloroethylene and benzene vapors onto hypercrosslinked polymeric resin

    International Nuclear Information System (INIS)

    In this research, the adsorption equilibria of trichloroethylene (TCE) and benzene vapors onto hypercrosslinked polymeric resin (NDA201) were investigated by the column adsorption method in the temperature range from 303 to 333 K and pressures up to 8 kPa for TCE, 12 kPa for benzene. The Toth and Dubinin-Astakov (D-A) equations were tested to correlate experimental isotherms, and the experimental data were found to fit well by them. The good fits and characteristic curves of D-A equation provided evidence that a pore-filling phenomenon was involved during the adsorption of TCE and benzene onto NDA-201. Moreover, thermodynamic properties such as the Henry's constant and the isosteric enthalpy of adsorption were calculated. The isosteric enthalpy curves varied with the surface loading for each adsorbate, indicating that the hypercrosslinked polymeric resin has an energetically heterogeneous surface. In addition, a simple mathematic model developed by Yoon and Nelson was applied to investigate the breakthrough behavior on a hypercrosslinked polymeric resin column at 303 K and the calculated breakthrough curves were in high agreement with corresponding experimental data.

  10. 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 ...

  11. INVESTIGATION OF BENZENE OXIDE IN BONE MARROW AND OTHER TISSUES OF F344 RATS FOLLOWING METABOLISM OF BENZENE IN VITRO AND IN VIVO

    Science.gov (United States)

    This study examines the initial activation of benzene, exploring key aspects of its metabolism by measurement of benzene oxide (BO) and BO-protein adducts in vitro and in vivo. To assess the potential influence of various factors on the production of BO, microsomes were prepare...

  12. Differences in the pathways for metabolism of benzene in rats and mice simulated by a physiological model.

    OpenAIRE

    Medinsky, M A; Sabourin, P J; Henderson, R F; Lucier, G; Birnbaum, L S

    1989-01-01

    Studies conducted by the National Toxicology Program on the chronic toxicity of benzene indicated that B6C3F1 mice were more sensitive to the carcinogenic effects of benzene than were F344 rats. A physiological model was developed to describe the uptake and metabolism of benzene in rats and mice. Our objective was to determine if differences in toxic effects could be explained by differences in pathways for benzene metabolism or by differences in total uptake of benzene. Compartments incorpor...

  13. Sorption of phenanthrene and benzene on differently structural kerogen: Important role of micropore-filling

    International Nuclear Information System (INIS)

    Shale was thermally treated to obtain a series of kerogen with varied maturation. Their chemical, structural and porous properties were related to the sorption and/or desorption behaviors of phenanthrene and benzene. As the treatment temperature increases, aliphatic and carbonyl carbon of the kerogen samples decrease, while their aromaticity and maturation increase. Meanwhile, the isothermal nonlinearity of phenanthrene and benzene increases whereas the sorption capacity and micropore adsorption volumes (Vo,d) initially increase and then decrease. The Vo,d of benzene is significantly correlated with, but higher than that of phenanthrene, suggesting similar micropore filling mechanism and molecular sieve effect. The benzene desorption exhibits hysteresis, which is related to the pore deformation of the kerogen and the entrapment of solute in the kerogen matrix. The Vo,d of phenanthrene and benzene on the kerogen samples accounts for 23–46% and 36–65% of the maximum sorption volumes, respectively, displaying the importance of the micropore filling. -- Highlights: • The microporosity estimated by benzene vapor differs greatly from that by N2. • The micropore volume changes with kerogen maturation. • The phenanthrene or benzene sorption is related to the microporosity of kerogen. • Higher adsorption volume for benzene than for phenanthrene suggests molecular sieve effect. • The pore-filling plays an important role in the sorption of phenanthrene and benzene. -- The sorption behaviors of benzene and phenanthrene are related to the microporosity of the differently matured kerogen, indicating the importance of pore-filling

  14. A mechanistic study on the reaction pathways leading to benzene and naphthalene in cellulose vapor phase cracking

    International Nuclear Information System (INIS)

    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. C3 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

  15. Peroxidase-dependent metabolism of benzene's phenolic metabolites and its potential role in benzene toxicity and carcinogenicity.

    OpenAIRE

    Smith, M T; Yager, J W; Steinmetz, K L; Eastmond, D A

    1989-01-01

    The metabolism of two of benzene's phenolic metabolites, phenol and hydroquinone, by peroxidase enzymes has been studied in detail. Studies employing horseradish peroxidase and human myeloperoxidase have shown that in the presence of hydrogen peroxide phenol is converted to 4,4'-diphenoquinone and other covalent binding metabolites, whereas hydroquinone is converted solely to 1,4-benzoquinone. Surprisingly, phenol stimulates the latter conversion rather than inhibiting it, an effect that may ...

  16. Critical issues in benzene toxicity and metabolism: The effect of interactions with other organic chemicals on risk assessment

    Energy Technology Data Exchange (ETDEWEB)

    Medinsky, M.A.; Schlosser, P.M.; Bond, J.A. [Chemical Industry Institute of Toxicology, Research Triangle Park, NC (United States)

    1994-11-01

    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 investigators have demonstrated that a combination of metabolites (hydroquinone and phenol, for example) is necessary to duplicate the hematotoxic effect of benzene. Enzymes implicated in the metabolic activation of benzene and its metabolites include the cytochrome P450 monooxygenases and myeloperoxidase. Since benzene and its hydroxylated metabolites (phenol, hydroquinone, and catechol) are substrates for the same cytochrome P450 enzymes, competitive interactions among the metabolites are possible. In vivo data on metabolite formation by mice exposed to various benzene concentrations are consistent with competitive inhibition of phenol oxidation by benzene. Other organic molecules that are substrates for cytochrome P450 can inhibit the metabolism of benzene. For example, toluene has been shown to inhibit the oxidation of benzene in a noncompetitive manner. Enzyme inducers, such as ethanol, can alter the target tissue dosimetry of benzene metabolites by inducing enzymes responsible for oxidation reactions involved in benzene metabolism. 24 refs., 6 figs., 2 tabs.

  17. Molecular Simulations of Adsorption and Diffusion Behaviors of Benzene Molecules in NaY Zeolite%NaY分子筛中苯分子吸附和扩散行为的分子模拟

    Institute of Scientific and Technical Information of China (English)

    张舟; 刘辉; 朱吉钦; 陈标华; 田辉平; 贺振富

    2009-01-01

    In the article the Grand Canonical Monte Carlo (GCMC), molecular dynamics (MD), and kinetic Monte Carlo (KMC) simulations with particular focus on ascertaining the loading dependence of benzene diffusion in the zeolite were performed. First, a realistic representation of the structure of the sorbate-sorbent system was obtained based on GCMC simulation. The simulation clearly shows the characteristics of the adsorption sites of the benzene-NaY system, from which two kinds of preferably adsorbing sites for benzene moleculcs, called SⅡ and W sites, are identified. The structure thus obtained was then used as a basis for KMC and MD simulations. A compara-tive study by introducing and comparing two different mechanisms underlying jump diffusion in the zeolite of in-terest shows that the MS diffusivity values predicted by the KMC and MD methods are fairly close to each other, leading to the conclusion that for benzene diffusion in NaY, the Su→W→SⅡ jumps of benzene molecules are dominated, while the W→W jumps do not exist in the process. These findings provide further support to our previous conclusion about the absence of the W→W jumps in the process of benzene diffusion in NaY. Finally, two relations for predicting the self-and MS diffusivities were derived and found to be in fair agreement with the KMC and MD simulations.

  18. Laboratory investigations of the interaction between benzene and bare silicate grain surfaces

    CERN Document Server

    Thrower, J D; McCoustra, M R S

    2008-01-01

    Experimental results on the thermal desorption of benzene (C6H6) from amorphous silica (SiO2) are presented. The amorphous SiO2 substrate was imaged using atomic force microscopy (AFM), revealing a surface morphology reminiscent of that of interplanetary dust particles (IDPs). Temperature programmed desorption (TPD) experiments were conducted for a wide range of C6H6 exposures, yielding information on both C6H6-SiO2 interactions and the C6H6-C6H6 interactions present in the bulk C6H6 ice. The low coverage experiments reveal complicated desorption behaviour that results both from porosity and roughness in the SiO2 substrate, and repulsive interactions between C6H6 molecules. Kinetic parameters were obtained through a combination of direct analysis of the TPD traces and kinetic modelling, demonstrating the coverage dependence of both desorption energy and pre-exponential factor. Experiments were also performed whereby the pores were blocked by pre-exposure of the SiO2 to water vapour. C6H6 was observed to be ad...

  19. Comparative study of the effects of toluene, benzene, 1,1,1-trichloroethane, diethyl ether, and flurothyl on anxiety and nociception in mice

    International Nuclear Information System (INIS)

    The main purpose of this study was to compare the effects of solvents from different chemical classes on anxiety and nociception. Independent groups of mice were exposed to air (control group), toluene (1000-4000 ppm), benzene (1000-4000 ppm), 1,1,1-trichloroethane (TCE, 2000-12000 ppm), diethyl ether (10,000-30,000) or flurothyl (200-600 ppm). After a 30-min exposure, animals were tested either in the anxiety paradigm conditioned defensive burying (CDB) test or in the hot plate test. All solvents but flurothyl produced anxiolytic-like actions being the order of potency toluene > benzene > TCE > diethyl ether. When tested in the hot plate paradigm, toluene and TCE increased nociception, benzene and diethyl ether had no effects, and flurothyl decreased nociception Additional groups of mice were conditioned to recognize the aversive stimulus (electrified prod) prior to toluene exposure and then tested in the CDB test. In unconditioned animals, toluene increased the number of shocks that mice received; however, when mice had previous experience in the CDB test, toluene lacked this effect. Taken together, these results show that inhalants have different effects with different potencies both in the CDB and in the hot plate tests. Additionally, data suggest that acute administration of toluene could impair learning

  20. Anaerobic degradation of benzene by enriched consortia with humic acids as terminal electron acceptors

    International Nuclear Information System (INIS)

    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.

  1. 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.

  2. Solar Powered Vapor Absorption System Using Propane And Alkylated Benzene Ab300 Oil

    OpenAIRE

    Al-Dadah, R.K.; Jackson, G.; Rezk, Ahmed

    2011-01-01

    Abstract This paper describes experimental work on a solar assisted vapour absorption air conditioning system using Propane (refrigerant) and Alkylated Benzene (AB300?refrigeration lubrication oil, absorbent). Preliminary experiments to assess the miscibility of propane in various lubricating oils namely Shell Clavus oils 32 and 64 and Alkylated Benzene oils AB150 and AB300 indicated that Propane is most miscible in Alkylated Benzene AB300. The vapour absorption system is a single ...

  3. ANALYSES OF CHROMOSOME ABERRATIONS IN LYMPHOCYTES AND BONE MARROW CELLS INDUCED BY RADIATION OR BENZENE

    Institute of Scientific and Technical Information of China (English)

    张鸿源; 王兰金; 等

    1995-01-01

    The chromosomoe and chromatid type aberration can be induced by benzene and the dicentric and ring ones were not observed in vitro experiment but observed in vivo one.In vitro experiment a good linear reression can be given between benzene concentrations and total aberration cells while power regression for radiation dose.The chromosome aberrations induced by benzene combined with radiation in rabbit blood lymphocytes are higher than in bone marryow cells.

  4. 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.

  5. Exposure Forecaster

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Exposure Forecaster Database (ExpoCastDB) is EPA's database for aggregating chemical exposure information and can be used to help with chemical exposure...

  6. Spectroscopic study of water-NaCl-benzene mixtures at high temperatures and pressures

    OpenAIRE

    Ohya, Tomoyuki; Kitagawa, Masaaki; Jin, Yusuke; Ikawa, Shun-ichi

    2005-01-01

    Near-infrared and ultraviolet spectra of water-NaCl-benzene mixtures have been measured in the 473–573 K and 100–400 bar range and 373–498 K and 50–300 bar range, respectively. Concentrations of water in the benzene-rich phase and benzene in the water-rich phase were estimated from integrated intensities of the absorption bands. It is found that addition of NaCl in the aqueous phase suppresses transfer of water into the benzene-rich phase, and the relative decrease in water solubility in ...

  7. 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

    2016-03-01

    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.

  8. Determination of benzene in different food matrices by distillation and isotope dilution HS-GC/MS

    International Nuclear Information System (INIS)

    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).

  9. Revisiting the glass transition and dynamics of supercooled benzene by calorimetric studies

    Science.gov (United States)

    Tu, Wenkang; Chen, Zeming; Li, Xiangqian; Gao, Yanqin; Liu, Riping; Wang, Li-Min

    2015-10-01

    The glass transition and dynamics of benzene are studied in binary mixtures of benzene with five glass forming liquids, which can be divided into three groups: (a) o-terphenyl and m-xylene, (b) N-butyl methacrylate, and (c) N,N-dimethylpropionamide and N,N-diethylformamide to represent the weak, moderate, and strong interactions with benzene. The enthalpies of mixing, ΔHmix, for the benzene mixtures are measured to show positive or negative signs, with which the validity of the extrapolations of the glass transition temperature Tg to the benzene-rich regions is examined. The extrapolations for the Tg data in the mixtures are found to converge around the point of 142 K, producing Tg of pure benzene. The fragility m of benzene is also evaluated by extrapolating the results of the mixtures, and a fragility m ˜ 80 is yielded. The obtained Tg and m values for benzene allow for the construction of the activation plot in the deeply supercooled region. The poor glass formability of benzene is found to result from the high melting point, which in turn leads to low viscosity in the supercooled liquid.

  10. Pressure Dependence of Molar Volume near the Melting Point in Benzene

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The pressure dependence of the molar volume was at constant temperatures close to the melting point in benzene. The molar volume of benzene was calculated using experimental data for the thermal expansivity for constant temperatures of 25℃, 28.5℃, 40℃, and 51℃ at various pressures for both the solid and liquid phases. The predictions are in good agreement with the observed volumes in both the solid and liquid phases of benzene. The predicted values of the molar volume for a constant temperature of 28.5℃ in the liquid phase of benzene agree well with experimental data in the literature.

  11. Modeling of Pervaporation Separation Benzene from Dilute Aqueous Solutions Through Polydimethylsiloxane Membranes

    Institute of Scientific and Technical Information of China (English)

    彭福兵; 姜忠义

    2005-01-01

    A modified solution-diffusion model was established based on Flory-Huggins thermodynamic theory and Fujita's free volume theory. This model was used for description of the mass transfer of removal benzene from dilute aqueous solutions through polydimethylsiloxane (PDMS) membranes. The effect of component concentration on the interaction parameter between components, that of the polymer membrane on the selectivity to benzene, and that of feed concentration and temperature on the permeation flux and separation factor of benzene/water through PDMS membranes were investigated. Calculated pervaporation fluxes of benzene and water were compared with the experimental results and were in good agreement with the experimental data.

  12. Diffusive Motions in Benzene and Toluene Studied with Slow Neutrons

    International Nuclear Information System (INIS)

    The viscosity of benzene is described by the Arrhenius equation ή = const. exp (E/kBT), where E is the activation energy for viscous flow. The viscosity of toluene, however, follows this law only in the higher temperature region of its liquid range, i.e. above the Arrhenius temperature TA. In the whole normal liquid range the benzene molecule is supposed to be able to rotate many times about at least two symmetry axes between translational jumps. Davies and Matheson suggest that the onset of non-Arrhenius viscosity behaviour in toluene occurs at that temperature at which rotation about two axes becomes restricted, while rotation about the third remains free. Inelastic scattering experiments of slow neutrons have been performed on the two substances using a time-of-flight spectrometer for cold neutrons with an energy resolution of 12 %. The quasi-elastic scattering has been studied for small momentum transfer as a function of temperature. Diffusion coefficients have been determined assuming a Lorentzian cross-section. The temperature dependence of the diffusion coefficient for benzene follows an exponential law, but the coefficient is a few times larger than the macroscopic coefficient, showing that a large amount of rotational diffusion exists. For toluene there is a change in the temperature dependence of the coefficient at about TA. This is taken as an indication of a change in the number of degrees of rotational freedom of the toluene molecule around TA. The methyl group in toluene has a low barrier to rotation (≲500 cal/mole). Therefore the hindered rotation levels of the methyl group as well as molecular rotation will contribute significantly to the inelastic scattering spectrum which overlaps the quasi-elastic peak. Th e inelastic component is subtracted by extrapolation but the possible contribution of the CH3 rotation to the quasi-elastic peak itself is neglected. (author)

  13. Velocity-dependent emission factors of benzene, toluene and C{sub 2}-benzenes of a passenger car equipped with and without a regulated 3-way catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Heeb, N.V.; Forss, A.-M.; Bach, C.; Mattrel, P. [Swiss Federal Laboratories for Materials Testing and Research, Duebendorf (Switzerland)

    2000-07-01

    Time-resolved chemical ionization mass spectrometry (Cl-MS) has been used to investigate the velocity-dependent emission factors for benzene, toluene, the C{sub 2}-benzenes (xylenes and ethyl benzene) and nitrogen monoxide of a gasoline-driven passenger car (1.4 l, model year 1995) driven with or without catalytic exhaust gas treatment. A set of seven different driving cycles - including the European Driving Cycle (EDC), the US Urban (FTP 75) and the Highway driving cycles - with a total driving time of 12,000 s have been studied. From the obtained emission data, two sets of 15,300 and 17,200 data points which represent transient driving in the velocity range of 0-150 km h{sup -1} and in an acceleration window of - 2-3 m s{sup -2} were explored to gain velocity-dependent emission factors. The passenger car, equipped with a regulated rhodium-platinum based three-way catalyst, showed optimal conversion efficiency (> 95%) for benzene in the velocity range of 60-120 km h{sup -1}. The conversion of benzene was reduced (< 80%) when driving below 50 km h{sup -1} and the BTXE emissions significantly increased when driven at higher speed and engine load (> 130 km h{sup -1}). Whereas the conversion efficiency for the class of C{sub 2}-benzenes was reduced to 10%, no net conversion could be found for toluene and benzene when driven above 130 km h{sup -1}. In contrast, the benzene and toluene emissions exceeded those of the untreated exhaust gas in the velocity range of 130-150 km h{sup -1} by 50-92% and by 10-34%, respectively. Thus, benzene and toluene were formed across the examined three-way catalyst if the engine is operated for an extended time in a fuel-rich mode (lambda < 1). (author)

  14. Atomic Structure of Benzene Which Accounts for Resonance Energy

    CERN Document Server

    Heyrovska, Raji

    2008-01-01

    Benzene is a hexagonal molecule of six carbon atoms, each of which is bound to six hydrogen atoms. The equality of all six CC bond lengths, despite the alternating double and single bonds, and the surplus (resonance) energy, led to the suggestion of two resonanting structures. Here, the new atomic structure shows that the bond length equality is due to three carbon atoms with double bond radii bound to three other carbon atoms with resonance bond radii (as in graphene). Consequently, there are two kinds of CH bonds of slightly different lengths. The bond energies account for the resonance energy.

  15. 4-Benzene­sulfonamido­benzoic acid

    OpenAIRE

    Sharif, Hafiz Muhammad Adeel; Dong, Gui-Ying; Arshad, Muhammad Nadeem; Khan, Islam Ullah

    2009-01-01

    In the mol­ecule of the title sulfonamide compound, C13H11NO4S, the dihedral angle between the planes of the benzene ring and the carboxyl substituent group is 6.7 (4)°. The two aromatic rings are inclined at 45.36 (15)° to one another. In the crystal, adjacent mol­ecules are linked via classical inter­molecular N—H⋯O and O—H⋯O, and non-classical C—H⋯O hydrogen bonds, which stabilize the crystal structure.

  16. 4-Benzene­sulfonamido­benzoic acid

    Science.gov (United States)

    Sharif, Hafiz Muhammad Adeel; Dong, Gui-Ying; Arshad, Muhammad Nadeem; Khan, Islam Ullah

    2009-01-01

    In the mol­ecule of the title sulfonamide compound, C13H11NO4S, the dihedral angle between the planes of the benzene ring and the carboxyl substituent group is 6.7 (4)°. The two aromatic rings are inclined at 45.36 (15)° to one another. In the crystal, adjacent mol­ecules are linked via classical inter­molecular N—H⋯O and O—H⋯O, and non-classical C—H⋯O hydrogen bonds, which stabilize the crystal structure. PMID:21578816

  17. Alkylation of benzene with normal olefins from coker distillate

    Energy Technology Data Exchange (ETDEWEB)

    Aboul-Gheit, A.K.; Moustafa, O.F.; Habbib, R.M.

    1985-10-01

    The normal olefins separated from a coker distillate were used to alkylate benzene on catalysts containing silicotungstic acid supported on silica, silica-alumina and activated natural clays. The alkylation activity was found to increase as the surface area and silica/alumina ratio of the catalysts increase, irrespective of the support texture. The activation energy of the reaction was very low (proportional3 k cal mol/sup -1/), assuming catalytic intraparticle diffusion limitation. Equilibrium shift towards dealkylation was observed beyond 300/sup 0/C. (orig.).

  18. 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.

  19. 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.)

  20. Endocrine-mediated effects of two benzene related compounds, 1-chloro-4-(chloromethyl)benzene and 1,3-diethyl benzene, based on subacute oral toxicity studies using rats.

    Science.gov (United States)

    Yamasaki, Kanji; Ishii, Satoko; Kikuno, Tsukasa; Minobe, Yasushi

    2012-08-01

    The purpose of this study was to investigate the endocrine-mediated effects of the benzene-related compounds with reference to Organization for Economic Co-operation and Development (OECD) Test Guideline No. 407. Rats were orally gavaged with 0, 10, 50, and 250 mg/kg/day of 1-chloro-4-(chloromethyl)benzene, and 0, 25, 150, and 1000 mg/kg/day of 1,3-diethyl benzene for at least 28 days, beginning at 8 weeks of age. Thyroid dysfunction was observed in rats given the 1,3-diethyl benzene. Serum T4 values increased in all groups of male rats and in the 1000 mg/kg group of female rats, and TSH values also increased in the 1000 mg/kg groups of both sexes after 28 days' administration. Decreased T3 values were observed in the 1000 mg/kg group of female rats after 28 days' administration, and hormone values increased in the 1000 mg/kg groups of both sexes after the 14-day recovery period. In addition, thyroid weight increased in the 1000 mg/kg groups and thyroid follicular cell hyperplasia was detected in one male rat from the 1000 mg/kg group after 28 days' administration. Endocrine-mediated effects, including thyroid dysfunction were not observed in any groups of rats treated with 1-chloro-4-(chloromethyl)benzene. Our results indicated that endocrine-mediated effects such as thyroid dysfunction were associated with some benzene-related compounds. PMID:22643015

  1. Muonated cyclohexadienyl radicals observed by level crossing resonance in dilute solutions of benzene in hexane subjected to muon-irradiation

    International Nuclear Information System (INIS)

    Benzene is used here as a scavenger of muonium to produce the muonated cyclohexadienyl radical in dilute solutions in n-hexane. The radical was identified by level crossing resonance spectroscopy (LFR) by observing the proton resonance of the -CHMu group occurring at 2.059T. Its yield is found to equal the sum of the muonium atom yield and the ''missing'' muon yield in hexane (total 35% of the incident muons). Consequently, the complete dispersement of muons in different chemical associations is now accounted for in a saturated hydrocarbon liquid, and is seen to be similar to that in water. (author)

  2. Muonated cyclohexadienyl radicals observed by level crossing resonance in dilute solutions of benzene in hexane subjected to muon-irradiation

    International Nuclear Information System (INIS)

    Benzene is used here as a scavenger of muonium to produce the muonated cyclohexadienyl radical in dilute solutions in n-hexane. The radical was identified by level crossing resonance spectroscopy (LCR) by observing the proton resonance of the -CHMu group occurring at 2.059T. Its yield is found to equal the sum of the muonium atom yield and the 'missing' muon yield in hexane (total 35% of the incident muons). Consequently, the complete dispersement of muons in different chemical associations is now accounted for in a saturated hydrocarbon liquid, and is seen to be similar to that in water

  3. Pesticide-Exposure Matrix

    Science.gov (United States)

    The "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.

  4. Aggregation of Benzene Molecules with Molecules of Methanol and Formic Acid

    International Nuclear Information System (INIS)

    Calculations and experimental studies of Raman scattering spectra show that there is a dimeric aggregation of benzene molecules with the molecule of methyl alcohol with the use of π-electrons of the benzene ring. In this process, the H-active hydrogen atom of O-H group is oriented to the edge of the benzene ring (a distance along the normal to the plane of the benzene ring is 2.850 A). The unusual position of the H-active hydrogen atom is conditioned by the interaction of two hydrogen atoms of the alcohols methyl group with π-electrons of the benzene ring. In Raman scattering spectra, the aggregation of molecules in the liquid state of the substance leads to a broadening of the band of full-symmetric vibrations with the maximum at 992 cm-1, as well as to a shift of this band toward lower frequencies by ∼ 1 cm-1. The band at 992 cm-1 is narrowed more than twice at the strong dilution of the benzene-methyl alcohol mixture by a large amount of heptane. The aggregation of benzene molecules takes place also with the molecules of formic acid with the use of π-electrons of the benzene ring. As in the case of the benzene-methyl alcohol mixture, the H-active hydrogen atom of O-H group of the acid is shifted toward the edge of the benzene ring. The energy of the benzene-formic acid dimerization is 9.2 kJ/mole.

  5. Impact of a new gasoline benzene regulation on ambient air pollutants in Anchorage, Alaska

    Science.gov (United States)

    Yano, Yuriko; Morris, Stephen S.; Salerno, Christopher; Schlapia, Anne M.; Stichick, Mathew

    2016-05-01

    The purpose of this study was to quantify the impact of a new U.S. Environmental Protection Agency (EPA) standard that limits the amount of benzene allowed in gasoline on ambient benzene concentrations. This new standard, together with two companion regulations that limit cold-temperature automotive emissions and the permeability of portable fuel containers, was expected to lower the levels of ambient benzene and other volatile organic compounds (VOCs) nationwide. In this study the impact of the gasoline benzene standard was evaluated in Anchorage, Alaska in a two-phase ambient air monitoring study conducted before and after the new gasoline standard was implemented. Gasoline sold by Anchorage retailers was also evaluated in each phase to determine the content of benzene and other gasoline components. The average benzene content in Anchorage gasoline was reduced by 70%, from 5.05% (w/w) to 1.53% (w/w) following the implementation of the standard. The annual mean ambient benzene concentration fell by 51%, from 0.99 ppbv in Phase 1 to 0.49 ppbv in Phase 2. Analysis suggests the change in gasoline benzene content alone reduced benzene emissions by 46%. The changes in toluene, ethylbenzene, and xylene content in gasoline between Phase 1 and 2 were relatively small and the differences in the mean ambient concentrations of these compounds between phases were modest. Our results suggest that cold winter communities in high latitude and mountainous regions may benefit more from the gasoline benzene standard because of high benzene emissions resulting from vehicle cold start and a tendency to develop atmospheric stagnation conditions in the winter.

  6. Chemical accuracy from quantum Monte Carlo for the benzene dimer.

    Science.gov (United States)

    Azadi, Sam; Cohen, R E

    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. PMID:26374029

  7. Chemical accuracy from quantum Monte Carlo for the benzene dimer

    International Nuclear Information System (INIS)

    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

  8. Chemical accuracy from quantum Monte Carlo for the Benzene Dimer

    CERN Document Server

    Azadi, Sam

    2015-01-01

    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 (DFT) using different van der Waals (vdW) functionals. In our 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 (PD) 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 CCSD(T)/CBS limit is -2.65(2) kcal/mol [E. 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, compar...

  9. Local Field Factors and Dielectric Properties of Liquid Benzene.

    Science.gov (United States)

    Davari, Nazanin; Daub, Christopher D; Åstrand, Per-Olof; Unge, Mikael

    2015-09-01

    Local electric field factors are calculated for liquid benzene by combining molecular dynamic simulations with a subsequent force-field model based on a combined charge-transfer and point-dipole interaction model for the local field factor. The local field factor is obtained as a linear response of the local field to an external electric field, and the response is calculated at frequencies through the first absorption maximum. It is found that the largest static local field factor is around 2.4, while it is around 6.4 at the absorption frequency. The linear susceptibility, the dielectric constant, and the first absorption maximum of liquid benzene are also studied. The electronic contribution to the dielectric constant is around 2.3 at zero frequency, in good agreement with the experimental value around 2.2, while it increases to 6.3 at the absorption frequency. The π → π* excitation energy is around 6.0 eV, as compared to the gas-phase value of around 6.3 eV, while the experimental values are 6.5 and 6.9 eV for the liquid and gas phase, respectively, demonstrating that the gas-to-liquid shift is well-described. PMID:26241379

  10. Diffusion and adsorption of benzene in Regina clay

    International Nuclear Information System (INIS)

    Surface or near-surface spills of hydrocarbons such as gasoline and diesel often occur in clay soils which are fractured and unsaturated. For cost-effective remediation, the extent of contamination and the distribution of the various phases should be determined before the development of remediation methods. The four volatile compounds that are commonly associated with gasoline leaking from underground fuel storage tanks are benzene, toluene, ethlybenzene and xylene. Existing diffusion test methods have been used successfully for inorganic species, but the successful application of these methods to volatile organic compounds is limited. The main difficulty with experiments using volatile organics is that there is a need for careful sample handling and sensitive analytical methods to accurately measure the aqueous concentration. Work was carried out to develop an apparatus that could be used to measure the diffusion and adsorption of volatile organics in clay. The best visual fit to the experimental data for the single reservoir test was an effective diffusion coefficient of 0.01 mL/g, and an adsorption coefficient of 0.1 mL/g. Based on diffusion cell tests, there are relatively low levels of retardation for benzene as it moves in clay soils with low organic carbon content. The implications for remediation are summarized. 28 refs., 16 figs., 5 tabs

  11. Thermodynamic investigation of the binary system of ethanol + benzene

    International Nuclear Information System (INIS)

    The molar heat capacity of the binary system ethanol + benzene was measured by an adiabatic calorimeter in the temperature range from 80 to 320 K. The glass transition and phase transitions of the mixture were determined based on the curve of the heat capacity with respect to temperature. The glass transition occurred at 97.536 K, the enthalpy and entropy of the glass transition were calculated to be 1.796 kJ mol-1, 18.414 J mol-1 K-1, respectively. The phase transitions took place in temperature ranges 115.875-128.400, 146.778-159.015 and 256.645-274.981 K corresponding to the solid-solid phase transition of ethanol, solid-liquid phase transition of ethanol and solid-liquid phase transition of benzene, respectively. The corresponding enthalpies and entropies of the phase transition were calculated to be -1.266 kJ mol-1, -10.745 J K-1 mol-1; 2.166 kJ mol-1, 13.818 J K-1 mol-1; 5.390 kJ mol-1, 19.856 J K-1 mol-1, respectively. The thermodynamic functions and the excess thermodynamic functions of the mixture relative to standard temperature 298.15 K were derived based on the relationships of the thermodynamic functions and the function of the measured heat capacity with respect to temperature

  12. Sonochemical treatment of benzene/toluene contaminated wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Thoma, G.; Gleason, M. [Univ. of Arkansas, Fayetteville, AR (United States). Dept. of Chemical Engineering; Popov, V. [Scientific Production Association Typhoon, Obninsk (Russian Federation). Inst. of Experimental Meterology

    1998-12-31

    Studies of the destruction of benzene and toluene in water were undertaken using ultrasonic irradiation in a parallel place Near Field Acoustic Processor (NAP). This magnetostrictive system is capable of degrading both benzene and toluene in a continuous stirred tank reactor configuration. The reaction kinetics were characterized by first order rate constants for the disappearance of the parent compound; these ranged from 2.7 {times} 1{sup {minus}3} to 3.7 {times} 10{sup {minus}2} mm{sup {minus}1} over an applied power density range of 0.6 to 3.6 watt mL{sup {minus}1} and target concentration of approximately 25 to 900 {micro}M. The rate constant is shown to be inversely proportional to the target compound concentration, indicating higher order reaction kinetics. The conversion efficiency for the system was characterized through the G efficiency commonly used in radiation chemistry. The G efficiency ranged between 4 {times} 10{sup {minus}5} to 2.2 {times} 10{sup {minus}4} molecules destroyed per 100 eV of electrical energy drawn from the wall outlet. These values are comparable to those of other advanced oxidation processes. Suggestions are made regarding methods to improve this technology.

  13. Alkylation of Benzene with Propylene Catalyzed by Ionic Liquids

    Institute of Scientific and Technical Information of China (English)

    Sun Xuewen; Zhao Suoqi

    2006-01-01

    The alkylation of benzene with propylene catalyzed by ionic liquids to obtain cumene was investigated. Propylene conversion and cumene selectivity under mild reaction conditions were improved greatly after the ionic liquid was modified with HCl. Under the conditions of 20 oC, 0.1MPa, 5 min of reaction time, and a molar ratio of benzene to propylene of 10:1, propylene conversion increased from 83.6% to 100%, and cumene selectivity increased from 90.86% to 98.47%. In addition, it was found that the reaction could be carried out in two different stages so as to obtain a better result. At the first stage, the key reaction was alkylation and a higher propylene conversion was obtained at a lower temperature;At the second stage, the key reaction was transalkylation and a higher temperature was used to improve cumene selectivity. The reaction temperature, pressure and the amount of catalyst used in this work were lower than those used in traditional alkylation processes.

  14. Separation of Benzene and Cyclohexane by Batch Extractive Distillation

    Institute of Scientific and Technical Information of China (English)

    XU Jiao; ZHANG Weijiang; GUI Xia

    2007-01-01

    Azeotropic liquid mixture cannot be separated by conventional distillation. But extractive distillation or combination of the two can be valid for them. An experiment to separate benzene and cyclohexane by batch extractive distillation was carried out with N, N-dimethylformide (DMF), dimethyl sulfoxide (DMSO) and their mixture as extractive solvent. The effect of the operation parameterssuch as solvent flow rate and reflux ratio on the separation was studied under the same operating conditions. The results show that the separation effect was improved with the increase of solvent flow rate and the reflux ratio; all the three extractive solvents can separate benzene and cyclohexane, with DMF being the most efficient one, the mixture the second, and DMSO the least. In the experiment the best operation conditions are with DMF as extractive solvent, the solvent flow rate being 12.33 mL/min, and the reflux ratio being 6. As a result, we can get cyclohexane from the top of tower with the average product content being 86.98%, and its recovering ratio being 83.10%.

  15. Effect of substrate interaction on oxidation of methane and benzene in enriched microbial consortia from landfill cover soil.

    Science.gov (United States)

    Lee, Eun-Hee; Park, Hyunjung; Cho, Kyung-Suk

    2011-01-01

    The interaction of methane and benzene during oxidation in enriched methane-oxidizing consortium (MOC) and in benzene-oxidizing consortium (BOC) from landfill cover soil was characterized. Oxidation of both methane and benzene occurred in the MOC due to the coexistence of bacteria responsible for benzene oxidation, as well as methanotrophs, whereas in the BOC, only benzene was oxidized, not methane. Methane oxidation rates in the MOC were decreased with increasing benzene/methane ratio (mol/mol), indicating its methane oxidation was inhibited by the benzene coexistence. Benzene oxidation rates in the MOC, however, were increased with increasing benzene/methane ratio. The benzene oxidation in the BOC was not affected by the coexistence of methane or by the ratio of methane/benzene ratio (mol/mol). No effect of methane or benzene was found on the dynamics of functional genes, such as particulate methane monooxygenase and toluene monooxygenase, in association with oxidation of methane and benzene in the MOC and BOC. PMID:21847790

  16. Benzene-Poly-Carboxylic Acid Complex, a Novel Anti-Cancer Agent Induces Apoptosis in Human Breast Cancer Cells

    Science.gov (United States)

    Fares, Fuad; Azzam, Naiel; Fares, Basem; Larsen, Stig; Lindkaer-Jensen, Steen

    2014-01-01

    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. PMID:24523856

  17. Phenol-induced stimulation of hydroquinone bioactivation in mouse bone marrow in vivo: Possible implications in benzene myelotoxicity

    International Nuclear Information System (INIS)

    The coadministration of phenol (PH) and hydroquinone (HQ) has been shown to produce myelotoxicity in mice similar to that observed following benzene exposure. One explanation of this phenomenon may be that PH enhances the peroxidase-dependent metabolic activation of HQ in the mouse bone marrow (BM). Here we report that 14C-HQ and 14C-PH bind covalently to tissue proteins of blood, BM, liver and kidney, when administered ip to the mouse in vivo. Phenol, when coadministered with 14C-Hq, significantly stimulated the covalent binding of 14C-HQ oxidation products to blood and BM proteins but had no significant effect on covalent binding of 14C-HQ oxidation products to liver and kidney proteins. When HQ was coadministered with 14C-PH, covalent binding of 14C-PH oxidation products to BM, kidney and blood proteins, was stimulated, whereas covalent binding in the liver was significantly inhibited. These results suggest that increased delivery to extrahepatic tissues is responsible for the enhanced covalent binding of HQ or PH to tissue proteins following their coadministration in vivo. They do not, however, rule out a secondary role for the PH-induced stimulation of peroxidase-mediated HQ metabolism in benzene myelotoxicity

  18. The interaction effects of binary mixtures of benzene and toluene on the developing heart of medaka (Oryzias latipes).

    Science.gov (United States)

    Teuschler, Linda K; Gennings, Chris; Hartley, William R; Carter, Hans; Thiyagarajah, Arunthavarani; Schoeny, Rita; Cubbison, Chris

    2005-03-01

    The United States Environmental Protection Agency (USEPA) has pursued the estimation of risk of adverse health effects from exposure to chemical mixtures since the early 1980s. Methods used to calculate risk estimates of mixtures were often based on single chemical information that required assumptions of dose-addition or response-addition and did not consider possible changes in response due to interaction effects among chemicals. Full factorial designs for laboratory studies can produce interactions information, but these are expensive to perform and may not provide the information needed to evaluate specific environmentally relevant mixtures. In this research, groups of Japanese medaka (Oryzias latipes) embryos were exposed to binary mixtures of benzene and toluene as well as to each of these chemicals alone. Endpoint specific dose-response models were built for the hydrocarbon mixture under an assumption of dose-additivity, using the single chemical dose-response information on benzene and toluene. The endpoints included heart rate, heart rate progression, and lethality. Results included a synergistic response for heart rate at 72 h of development, and either additivity or antagonism for all other endpoints at 96 h of development. This work uses an established statistical method to evaluate the toxicity of an environmentally relevant mixture to ascertain whether interaction effects are occurring, thus providing additional information on toxicity. PMID:15667848

  19. Benzene bioremediation using cow dung microflora in two phase partitioning bioreactor

    International Nuclear Information System (INIS)

    Bioremediation of benzene has been carried out using cow dung microflora in a bioreactor. The bioremediation of benzene under the influence of cow dung microflora was found to be 100% and 67.5%, at initial concentrations of 100 mg/l and 250 mg/l within 72 h and 168 h respectively; where as at higher concentration (500 mg/l), benzene was found to be inhibitory. Hence the two phase partitioning bioreactor (TPPB) has been designed and developed to carryout biodegradation at higher concentration. In TPPB 5000 mg/l benzene was biodegraded up to 50.17% over a period of 168 h. Further the Pseudomonas putida MHF 7109 was isolated from cow dung microflora as potential benzene degrader and its ability to degrade benzene at various concentrations was evaluated. The data indicates 100%, 81% and 65% degradation at the concentrations of 50 mg/l, 100 mg/l, 250 mg/l within the time period of 24 h, 96 h and 168 h respectively. The GC-MS data also shows the presence of catechol and 2-hydroxymuconic semialdehyde, which confirms the established pathway of benzene biodegradation. The present research proves the potential of cow dung microflora as a source of biomass for benzene biodegradation in TPPB.

  20. 40 CFR 721.1230 - Benzene, ethenyl-, ar-bromo derivatives.

    Science.gov (United States)

    2010-07-01

    ... removed from a container that has held the substance, unless the container is empty as defined in 40 CFR... 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...

  1. 78 FR 25476 - Agency Information Collection Activities; Submission for OMB Review; Comment Request; Benzene...

    Science.gov (United States)

    2013-05-01

    ... information, see the related notice published in the Federal Register on February 28, 2013 (78 FR 13707...; 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...

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

    Science.gov (United States)

    2010-07-01

    ... that has held the substance, unless the container is empty as defined in 40 CFR 261.7(b)(3); any... 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)...

  3. Benzene emission from the actual car fleet in relation to petrol composition in Denmark

    International Nuclear Information System (INIS)

    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 NOx 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 NOx. The decreasing trends of NOx 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)

  4. 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, ...

  5. Benzene emission from the actual car fleet in relation to petrol composition in Denmark

    Science.gov (United States)

    Palmgren, Finn; Hansen, Asger B.; Berkowicz, Ruwim; Skov, Henrik

    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.

  6. Homolytic iodination and nitration of some benzene derivatives in the gas phase

    International Nuclear Information System (INIS)

    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 NO2 is determined. (C.F.)

  7. 46 CFR Appendix B to Subpart C to... - Substance Technical Guidelines, Benzene

    Science.gov (United States)

    2010-10-01

    ...) Benzene is classified as a flammable liquid for the purpose of conforming to the requirements of 49 CFR... locations for the purposes of conforming to the requirements of 46 CFR parts 30 through 40, 151, and 153.... (Benzin, petroleum benzin, and benzine do not contain benzene). (2) Formula: C6 H6 (CAS Registry...

  8. Benzene bioremediation using cow dung microflora in two phase partitioning bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Dipty [Environmental Biotechnology Laboratory, Department of Life Sciences, University of Mumbai, Vidyanagari Campus, Santacruz (E), Mumbai-400 098 (India); Fulekar, M.H., E-mail: mhfulekar@yahoo.com [Environmental Biotechnology Laboratory, Department of Life Sciences, University of Mumbai, Vidyanagari Campus, Santacruz (E), Mumbai-400 098 (India)

    2010-03-15

    Bioremediation of benzene has been carried out using cow dung microflora in a bioreactor. The bioremediation of benzene under the influence of cow dung microflora was found to be 100% and 67.5%, at initial concentrations of 100 mg/l and 250 mg/l within 72 h and 168 h respectively; where as at higher concentration (500 mg/l), benzene was found to be inhibitory. Hence the two phase partitioning bioreactor (TPPB) has been designed and developed to carryout biodegradation at higher concentration. In TPPB 5000 mg/l benzene was biodegraded up to 50.17% over a period of 168 h. Further the Pseudomonas putida MHF 7109 was isolated from cow dung microflora as potential benzene degrader and its ability to degrade benzene at various concentrations was evaluated. The data indicates 100%, 81% and 65% degradation at the concentrations of 50 mg/l, 100 mg/l, 250 mg/l within the time period of 24 h, 96 h and 168 h respectively. The GC-MS data also shows the presence of catechol and 2-hydroxymuconic semialdehyde, which confirms the established pathway of benzene biodegradation. The present research proves the potential of cow dung microflora as a source of biomass for benzene biodegradation in TPPB.

  9. Hydrogenation of Benzene over Mo2C/Al2O3 Catalyst

    Institute of Scientific and Technical Information of China (English)

    Zhang Jing; Wu Weicheng

    2008-01-01

    The process of benzene hydrogenation over Mo2C catalyst has been studied.Mo2C was the active phase in benzene hydrogenation.The major problem with the metal carbides was their poor stability due to deactivation by carbon deposition.

  10. Differential susceptibility of rats and guinea pigs to the ototoxic effects of ethyl benzene

    NARCIS (Netherlands)

    Cappaert, NLM; Klis, SFL; Muijser, H; Kulig, BM; Ravensberg, LC; Smoorenburg, GF

    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 foun

  11. Accurate computations of the structures and binding energies of the imidazole⋯benzene and pyrrole⋯benzene complexes

    International Nuclear Information System (INIS)

    Highlights: • We have computed accurate binding energies of two NH⋯π hydrogen bonds. • We compare to results from dispersion-corrected density-functional theory. • A double-hybrid functional with explicit correlation has been proposed. • First results of explicitly-correlated ring-coupled-cluster theory are presented. • A double-hybrid functional with random-phase approximation is investigated. - Abstract: Using explicitly-correlated coupled-cluster theory with single and double excitations, the intermolecular distances and interaction energies of the T-shaped imidazole⋯benzene and pyrrole⋯benzene complexes have been computed in a large augmented correlation-consistent quadruple-zeta basis set, adding also corrections for connected triple excitations and remaining basis-set-superposition errors. The results of these computations are used to assess other methods such as Møller–Plesset perturbation theory (MP2), spin-component-scaled MP2 theory, dispersion-weighted MP2 theory, interference-corrected explicitly-correlated MP2 theory, dispersion-corrected double-hybrid density-functional theory (DFT), DFT-based symmetry-adapted perturbation theory, the random-phase approximation, explicitly-correlated ring-coupled-cluster-doubles theory, and double-hybrid DFT with a correlation energy computed in the random-phase approximation

  12. Accurate computations of the structures and binding energies of the imidazole⋯benzene and pyrrole⋯benzene complexes

    Energy Technology Data Exchange (ETDEWEB)

    Ahnen, Sandra; Hehn, Anna-Sophia [Institute of Physical Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 2, D-76131 Karlsruhe (Germany); Vogiatzis, Konstantinos D. [Institute of Physical Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 2, D-76131 Karlsruhe (Germany); Center for Functional Nanostructures, Karlsruhe Institute of Technology (KIT), Wolfgang-Gaede-Straße 1a, D-76131 Karlsruhe (Germany); Trachsel, Maria A.; Leutwyler, Samuel [Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, CH-3012 Bern (Switzerland); Klopper, Wim, E-mail: klopper@kit.edu [Institute of Physical Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 2, D-76131 Karlsruhe (Germany); Center for Functional Nanostructures, Karlsruhe Institute of Technology (KIT), Wolfgang-Gaede-Straße 1a, D-76131 Karlsruhe (Germany)

    2014-09-30

    Highlights: • We have computed accurate binding energies of two NH⋯π hydrogen bonds. • We compare to results from dispersion-corrected density-functional theory. • A double-hybrid functional with explicit correlation has been proposed. • First results of explicitly-correlated ring-coupled-cluster theory are presented. • A double-hybrid functional with random-phase approximation is investigated. - Abstract: Using explicitly-correlated coupled-cluster theory with single and double excitations, the intermolecular distances and interaction energies of the T-shaped imidazole⋯benzene and pyrrole⋯benzene complexes have been computed in a large augmented correlation-consistent quadruple-zeta basis set, adding also corrections for connected triple excitations and remaining basis-set-superposition errors. The results of these computations are used to assess other methods such as Møller–Plesset perturbation theory (MP2), spin-component-scaled MP2 theory, dispersion-weighted MP2 theory, interference-corrected explicitly-correlated MP2 theory, dispersion-corrected double-hybrid density-functional theory (DFT), DFT-based symmetry-adapted perturbation theory, the random-phase approximation, explicitly-correlated ring-coupled-cluster-doubles theory, and double-hybrid DFT with a correlation energy computed in the random-phase approximation.

  13. 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.

  14. Benzaldehyde in cherry flavour as a precursor of benzene formation in beverages.

    Science.gov (United States)

    Loch, Christine; Reusch, Helmut; Ruge, Ingrid; Godelmann, Rolf; Pflaum, Tabea; Kuballa, Thomas; Schumacher, Sandra; Lachenmeier, Dirk W

    2016-09-01

    During sampling and analysis of alcohol-free beverages for food control purposes, a comparably high contamination of benzene (up to 4.6μg/L) has been detected in cherry-flavoured products, even when they were not preserved using benzoic acid (which is a known precursor of benzene formation). There has been some speculation in the literature that formation may occur from benzaldehyde, which is contained in natural and artificial cherry flavours. In this study, model experiments were able to confirm that benzaldehyde does indeed degrade to benzene under heating conditions, and especially in the presence of ascorbic acid. Analysis of a large collective of authentic beverages from the market (n=170) further confirmed that benzene content is significantly correlated to the presence of benzaldehyde (r=0.61, pcherry flavoured beverages, industrial best practices should include monitoring for benzene. Formulations containing either benzoic acid or benzaldehyde in combination with ascorbic acid should be avoided. PMID:27041300

  15. Hydrogen Storage in Benzene Moiety Decorated Single-Walled Carbon Nanotubes

    Institute of Scientific and Technical Information of China (English)

    ZHANG Bing-Yun; LIANG Qi-Min; SONG Chen; XIA Yue-Yuan; ZHAO Ming-wen; LIU Xiang-Dong; ZHANG Hong-Yu

    2006-01-01

    The hydrogen storage capacity of(5,5)single-walled carbon nanotubes(SWNTs)decorated chemically with benzene moieties is studied by using molecular dynamics simulations(MDSs)and density functional theory(DFT) calculations.It is found that benzene molecules colliding on (5,5) SWNTs at incident energy of 50 eV form very stable configurations of benzene moiety adsorption on the wall of SWNTs.The MDSs indicate that when the benzene moiety decorated(5,5)SWNTs and a pristine(5,5)SWNT are put in a box in which hydrogen molecules are filled to a pressure of~26 atm,the hydrogen storage capacity of the benzene moiety decorated(5,5)SWNT is about 4.7wt.% and that of the pristine (5,5) SwNT is nearly 3.9 wt.%.

  16. EPHECT II: Exposure assessment to household consumer products.

    Science.gov (United States)

    Dimitroulopoulou, C; Trantallidi, M; Carrer, P; Efthimiou, G C; Bartzis, J G

    2015-12-01

    Within the framework of the EPHECT project (Emissions, exposure patterns and health effects of consumer products in the EU), irritative and respiratory health effects were assessed in relation to acute and long-term exposure to key and emerging indoor air pollutants emitted during household use of selected consumer products. In this context, inhalation exposure assessment was carried out for six selected 'target' compounds (acrolein, formaldehyde, benzene, naphthalene, d-limonene and α-pinene). This paper presents the methodology and the outcomes from the micro-environmental modelling of the 'target' pollutants following single or multiple use of selected consumer products and the subsequent exposure assessment. The results indicate that emissions from consumer products of benzene and α-pinene were not considered to contribute significantly to the EU indoor background levels, in contrast to some cases of formaldehyde and d-limonene emissions in Eastern Europe (mainly from cleaning products). The group of housekeepers in East Europe appears to experience the highest exposures to acrolein, formaldehyde and benzene, followed by the group of the retired people in North, who experiences the highest exposures to naphthalene and α-pinene. High exposure may be attributed to the scenarios developed within this project, which follow a 'most-representative worst-case scenario' strategy for exposure and health risk assessment. Despite the above limitations, this is the first comprehensive study that provides exposure estimates for 8 population groups across Europe exposed to 6 priority pollutants, as a result of the use of 15 consumer product classes in households, while accounting for regional differences in uses, use scenarios and ventilation conditions of each region. PMID:26173853

  17. 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)

    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 60Co, 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)

  18. (Liquid + liquid) equilibria for benzene + cyclohexane + N,N-dimethylformamide + sodium thiocyanate

    International Nuclear Information System (INIS)

    Graphical abstract: On the left, the figure was phase diagram about the LLE date. On the right, the figure was about the effects of mass fraction of benzene in the raffinate phase to the selectivity(S) coefficient under different salt concentration. ■, the NaSCN and DMF in ratio of 5/95; • , the NaSCN and DMF in ratio of 10/90; ▴, the NaSCN and DMF in ratio of 15/85; ★, the NaSCN and DMF in ratio of 20/80; ▾, the NaSCN and DMF in ratio of 23/77. ♦, only DMF was used extractant (the selectivity coefficient was calculated by literature 17). w22, refer to the mass fraction of benzene in the raffinate phase (cyclohexane-rich phase). Highlights: • (Liquid + liquid) equilibrium for quaternary system was measured. • The components include benzene, cyclohexane, N,N-dimethylformamide, sodium thiocyanate. • The (liquid + liquid) equilibrium data can be well correlated by the NRTL model. • Separation of benzene and cyclohexane by NaSCN + DMF was discussed. -- Abstract: (Liquid + liquid) equilibrium (LLE) data for benzene + cyclohexane + N,N-dimethylformamide (DMF) + sodium thiocyanate (NaSCN) were measured experimentally at atmospheric pressure and 303.15 K. The selectivity coefficients from these LLE data were calculated and compared to those previously reported in the literature for the systems (benzene + cyclohexane + DMF) and (benzene + cyclohexane + DMF + KSCN). The NRTL equation was used to correlate the experimental data. The agreement between the predicted and experimental results was good. It was found that the selectivity coefficients of DMF + NaSCN for benzene ranged from 2.45 to 11.99. Considering the relatively high extraction capacity and selectivity for benzene, DMF + NaSCN may be used as a potential extracting solvent for the separation of benzene from cyclohexane

  19. Effect Of Polar Component(1-Propanol On The RelativeVolatility Of The Binary System N-Hexane - Benzene

    Directory of Open Access Journals (Sweden)

    Khalid Farhod Chasib Al-Jiboury

    2008-01-01

    Full Text Available Vapor-liquid equilibrium data are presented for the binary systems n-hexane - 1-propanol, benzene - 1-propanol and n-hexane – benzene at 760 mm of mercury pressure. In addition ternary data are presented at selected compositions with respect to the 1-propanol in the 1-propanol, benzene, n-hexane system at 760 mmHg. The results indicate the relative volatility of n-hexane relative to benzene increases appreciably with addition of 1-propanol

  20. In situ FTIR Investigation of Magnetic Field Effect on Heterogeneous Photocatalytic Degradation of Benzene over Pt/TiO2

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    In situ FTIR spectroscopy was utlized to investigate the magnetic field effect on the heterogeneous photocatalytic degradation of benzene over platinized titania (Pt/TiO2). The results revealed that the employment of magnetic field may not change the mechanism of photocatalytic degradation of benzene, however, it greatly facilitate the conversion of benzene to phenol and quinone, as well as the transformation from phenol to quinone, resulting in opening the benzene ring easily and promoting the production of CO2.

  1. Removal of the hazardous, volatile, and organic compound benzene from aqueous solution using phosphoric acid activated carbon from rice husk

    OpenAIRE

    Yakout, Sobhy M

    2014-01-01

    Background Benzene is one of the most hazardous organic pollutants in groundwater. The removal of benzene from water is very important from a health point of view and for environmental protection. In this study, benzene adsorption kinetics was investigated using phosphoric acid activated carbon, prepared from rice husk. Results An initial rapid uptake of benzene was observed and became almost constant after 40 minutes of contact. Kinetic data was analyzed using pseudo first order, pseudo seco...

  2. p-Benzoquinone, a reactive metabolite of benzene, prevents the processing of pre-interleukins-1{alpha} and -1{beta} to active cytokines by inhibition of the processing enzymes, calpain, and interleukin-1{beta} converting enzyme

    Energy Technology Data Exchange (ETDEWEB)

    Kalf, G.F.; Renz, J.F.; Niculescu, R. [Thomas Jefferson Univ., Philadelphia, PA (United States)

    1996-12-01

    Chronic exposure of humans to benzene affects hematopoietic stem and progenitor cells and leads to aplastic anemia. The stromal macrophage, a target of benzene toxicity, secretes interieukin-1 (IL-1), which induces the stromal fibroblast to synthesize hematopoietic colony-stimulating factors. In a mouse model, benzene causes an acute marrow hypocellularity that can be prevented by the concomitant administration of IL-1{alpha}. The ability of benzene to interfere with the production and secretion of IL-1{alpha} was tested. Stromal macrophages from benzene-treated mice were capable of the transcription of the IL-1{alpha} gene and the translation of the message but showed an inability to process the 34-kDa pre-IL-1{alpha} precursor to the 17-kDa biologically active cytokine. Treatment of normal murine stromal macrophages in culture with hydroquinone (HQ) also showed an inhibition in processing of pre-IL-1{alpha}. Hydroquinone is oxidized by a peroxidase-mediated reaction in the stromal macrophage to p-benzoquinone, which interacts with the sulfhydryl (SH) groups of proteins and was shown to completely inhibit the activity of calpain, the SH-dependent protease that cleaves pre-IL-1{alpha}. In a similar manner, HQ, via peroxidase oxidation to p-benzoquinone, was capable of preventing the IL-1{beta} autocrine stimulation of growth of human B1 myeloid tumor cells by preventing the processing of pre-IL-1{beta} to mature cytokine. Benzoquinone was also shown to completely inhibit the ability of the SH-dependent IL-1{beta} converting enzyme. Thus benzene-induced bone marrow hypocellularity may result from apoptosis of hematopoietic progenitor cells brought about by lack of essential cylokines and deficient IL-1{alpha} production subsequent to the inhibition of calpain by p-benzoquinone and the prevention of pre-IL-1 processing. 34 refs., 8 figs.

  3. 40 CFR 80.1352 - What are the pre-compliance reporting requirements for the gasoline benzene program?

    Science.gov (United States)

    2010-07-01

    ... requirements for the gasoline benzene program? 80.1352 Section 80.1352 Protection of Environment ENVIRONMENTAL... Benzene Recordkeeping and Reporting Requirements § 80.1352 What are the pre-compliance reporting requirements for the gasoline benzene program? (a) Except as provided in paragraph (c) of this section,...

  4. Pre-commissioning of 120 kt/a Unit for Hydrotreating Crude Coke Oven Benzene Implemented at Baoyuan Chemical Company

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ The Baoyuan Chemical Company, Ltd. in Taiyuan has per-formed the precommissioning of a 120 kt/a unit for hydrotreating crude coke oven benzene. This unit is the phase II construction of the 300 kt/a crude benzene hydrotreating project, which adopts the process technology for hydrotreating crude coke oven benzene developed indepen-dently by our own efforts.

  5. 40 CFR 721.984 - Amino-hydroxy sulfonaphthylazo-disubstituted phenyl azo benzene carboxylate salt (generic).

    Science.gov (United States)

    2010-07-01

    ...-disubstituted phenyl azo benzene carboxylate salt (generic). 721.984 Section 721.984 Protection of Environment...-disubstituted phenyl azo benzene carboxylate salt (generic). (a) Chemical substance and significant new uses...-disubstituted phenyl azo benzene carboxylate salt (PMN P-00-0351) is subject to reporting under this section...

  6. Nonthermal plasma assisted photocatalytic oxidation of dilute benzene

    Indian Academy of Sciences (India)

    J Karuppiah; E Linga Reddy; L Sivachandiran; R Karvembu; Ch Subrahmanyam

    2012-07-01

    Oxidative decomposition of low concentrations (50-1000 ppm) of diluted benzene in air was carried out in a nonthermal plasma (NTP) dielectric barrier discharge (DBD) reactor with the inner electrode made up of stainless steel fibres (SMF) modified with transition metal oxides in such a way to integrate the catalyst in discharge zone. Typical results indicate the better performance of MnO and TiO2/MnO modified systems, which may be attributed to the in situ decomposition of ozone on the surface of MnO that may lead to the formation of atomic oxygen; whereas ultraviolet light induced photocatalytic oxidation may be taking place with TiO2 modified systems. Water vapour improved the selectivity to total oxidation.

  7. Adsorption of benzene, cyclohexane and hexane on ordered mesoporous carbon.

    Science.gov (United States)

    Wang, Gang; Dou, Baojuan; Zhang, Zhongshen; Wang, Junhui; Liu, Haier; Hao, Zhengping

    2015-04-01

    Ordered mesoporous carbon (OMC) with high specific surface area and large pore volume was synthesized and tested for use as an adsorbent for volatile organic compound (VOC) disposal. Benzene, cyclohexane and hexane were selected as typical adsorbates due to their different molecular sizes and extensive utilization in industrial processes. In spite of their structural differences, high adsorption amounts were achieved for all three adsorbates, as the pore size of OMC is large enough for the access of these VOCs. In addition, the unusual bimodal-like pore size distribution gives the adsorbates a higher diffusion rate compared with conventional adsorbents such as activated carbon and carbon molecular sieve. Kinetic analysis suggests that the adsorption barriers mainly originated from the difficulty of VOC vapor molecules entering the pore channels of adsorbents. Therefore, its superior adsorption ability toward VOCs, together with a high diffusion rate, makes the ordered mesoporous carbon a promising potential adsorbent for VOC disposal. PMID:25872710

  8. Nonlinear response of the benzene molecule to strong magnetic fields

    Science.gov (United States)

    Pagola, G. I.; Caputo, M. C.; Ferraro, M. B.; Lazzeretti, P.

    2005-02-01

    The fourth-rank hypermagnetizability tensor of the benzene molecule has been evaluated at the coupled Hartree-Fock level of accuracy within the conventional common-origin approach, adopting gaugeless basis sets of increasing size and flexibility. The degree of convergence of theoretical tensor components has been estimated allowing for two different coordinate systems. It is shown that a strong magnetic field perpendicular to the plane of the molecule causes a distortion of the electron charge density, which tends to concentrate in the region of the C-C bonds. This charge contraction has a dynamical origin, and can be interpreted as a feedback effect in terms of the classical Lorentz force acting on the electron current density.

  9. Modeling Biodegradation Kinetics on Benzene and Toluene and Their Mixture

    Directory of Open Access Journals (Sweden)

    Aparecido N. Módenes

    2007-10-01

    Full Text Available The objective of this work was to model the biodegradation kinetics of toxic compounds toluene and benzene as pure substrates and in a mixture. As a control, Monod and Andrews models were used. To predict substrates interactions, more sophisticated models of inhibition and competition, and SKIP (sum kinetics interactions parameters model were applied. The models evaluation was performed based on the experimental data from Pseudomonas putida F1 activities published in the literature. In parameter identification procedure, the global method of particle swarm optimization (PSO was applied. The simulation results show that the better description of the biodegradation process of pure toxic substrate can be achieved by Andrews' model. The biodegradation process of a mixture of toxic substrates is modeled the best when modified competitive inhibition and SKIP models are used. The developed software can be used as a toolbox of a kinetics model catalogue of industrial wastewater treatment for process design and optimization.

  10. Benzene ring chains with lithium adsorption: Vibrations and their implications

    CERN Document Server

    Stegmann, Thomas; Seligman, Thomas H

    2016-01-01

    Lithium adsorption on aromatic molecules and polyacenes have been found to produce strong distortions associated to spontaneous symmetry breaking and lesser ones in more general cases. For polyphenyls we find similar, but more varied behaviour; an important feature is the fact that adsorption largely suppresses the torsion present in naked polyphenyl. The spectra of the vibrational modes distinguish the different structures of skeletons and adsorbates. In the more regular adsorption schemes the lowest states are bending and torsion modes of the skeleton, which are essential followed by the adsorbate. Based on this we propose the possible use of such a chain of adsorbates on a chain of benzene rings as a quantum register with the lowest vibrations transmitting qubits for control gates. To strengthen this view and to show the effect of heavier alkalines we also present the very symmetric adsorption of ten rubidium atoms on pentaphenyl.

  11. Solvent isotope effect on viscosity of polystyrene-benzene solutions

    International Nuclear Information System (INIS)

    The concentration and temperature dependencies of viscosity and density of solutions of nearly monodisperse samples (Mw/Mn w) ranging from 4x103 to 4x105 between 293-313 K. Isotope H/D substitution in benzene causes visible changes in viscosity and density of solutions, however, its influence on intrinsic viscosities and Huggins constants, derived from the concentration dependences of viscosity, is negligible. No isotope effects on the exponents in the power low relationship have been detected. The viscosities of the solutions have been also correlated with the densities. The apparent close-packed volumes are practically constant for all solutions and seem to be determined by the properties of the solvent. The deuterium substitution visibly affects the close-packed volumes - they decrease by approximately 13%, both in pure solvent and in solutions. (author)

  12. Radiolysis of Aqueous Benzene Solutions at higher temperatures

    International Nuclear Information System (INIS)

    Aqueous solutions of benzene have been irradiated with Co γ-rays with doses of up to 2.3 Mrad in the temperature region 100 - 200 C. At 100 C a linear relationship between the phenol concentration and the absorbed dose was obtained, but at 150 C and at higher temperatures the rate of the phenol formation increased significantly after an initial constant period. With higher doses the rate decreased again, falling almost to zero at 200 C after a dose of 2.2 Mrad. The G value of phenol in the initial linear period increased from 2.8 at 100 C to 8.0 at 200 C. The reaction mechanism is discussed and reactions constituting a chain reaction are suggested. The result of the addition of iron ions and of a few inorganic oxides to the system is presented and briefly discussed

  13. Separation of Scintillation and Cherenkov Lights in Linear Alkyl Benzene

    CERN Document Server

    Li, Mohan; Yeh, Minfang; Wang, Zhe; Chen, Shaomin

    2015-01-01

    To separate scintillation and Cherenkov lights in water-based liquid scintillator detectors is a desired feature for future neutrino and proton decay researches. Linear alkyl benzene (LAB) is one important ingredient of a water-based liquid scintillator being developed. In this paper we observed a good separation of scintillation and Cherenkov lights in an LAB sample. The rising and decay times of the scintillation light of the LAB were measured to be $(7.7\\pm3.0)\\ \\rm{ns}$ and $(36.6\\pm2.4)\\ \\rm{ns}$, respectively, while the full width [-3$\\sigma$, 3$\\sigma$] of the Cherenkov light was 12 ns dominated by the time resolution of our photomultiplier tubes. The light yield of the scintillation was measured to be $(1.01\\pm0.12)\\times10^3\\ \\rm{photons}/\\rm{MeV}$.

  14. Benzene Uptake and Glutathione S-transferase T1 Status as Determinants of S-Phenylmercapturic Acid in Cigarette Smokers in the Multiethnic Cohort

    Science.gov (United States)

    Haiman, Christopher A.; Patel, Yesha M.; Stram, Daniel O.; Carmella, Steven G.; Chen, Menglan; Wilkens, Lynne R.; Le Marchand, Loic; Hecht, Stephen S.

    2016-01-01

    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. PMID:26959369

  15. 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.

  16. Advice of the Italian CCTN on the health risk assessment relative to exposure to automobile emissions

    Energy Technology Data Exchange (ETDEWEB)

    Camoni, I. [ed.] [Istituto Superiore di Sanita`, Rome (Italy). Lab. di Tossicologia Applicata; Mucci, N. [ed.] [ISPESL, Monteporzio Catone, Roma (Italy). Dip. di Medicina del Lavoro; Foa`, V. [ed.] [Milan Univ. (Italy). Clinica del lavoro Luigi Devoto

    1998-06-01

    The period 1990-1995 are reported, they concern the health impact of exposure to benzene and polycyclic aromatic hydrocarbons (PAHs), resulting from automobile exhaust products, for Italian general and occupationally exposed populations. The first recommendation takes into consideration the possible long-term effects of the unleaded gasoline, recently introduced in Italy. The latter two recommendations concern the quantitative evaluation of the risk of leukaemia and of the risk of lung cancer from exposure to benzene and PAHs, resulting from automobile exhaust. [Italiano] Sono riportati i pareri espressi dalla Commissione Consultiva Tossicologica Nazionale (CCTN) nel periodo 1990-1995 riguardanti la valutazione del rischio cancerogeno per esposizione a sostanze contenute nelle emissioni autoveicolari. In particolare, viene stimato il rischio aggiuntivo di leucemia per esposizione a benzene e di cancro polmonare per esposizione a idrocarburi policiclici aromatici (IPA), sia per la popolazione generale che per quella professionalmente esposta.

  17. 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

  18. Electrochemical degradation of benzene in natural water using silver nanoparticle-decorated carbon nanotubes

    International Nuclear Information System (INIS)

    In this study, a novel methodology for the electrochemical degradation of benzene in natural water using silver nanoparticle-decorated carbon nanotubes has been investigated. The morphology, the structure, and the electrochemical performance of the multi-walled carbon nanotubes-silver (MWCNT-Ag) nanocomposite film were characterised by transmission electron microscopy (TEM), X-ray diffraction (XRD), and cyclic voltammetry (CV), respectively. Electrocatalytic oxidation of benzene in an aqueous solution was studied to evaluate potential applications of the MWCNT-Ag modified glassy carbon (GC) electrode in environmental science. The benzene removal efficiency in natural water containing 10 mg L−1 benzene yielded 77.9% at an applied potential of +2.0 V for 2 h using the MWCNT-Ag-GC electrode. In comparison, the removal efficiency reached only 8.0% with the bare GC electrode, showing the suitability of the MWCNT-Ag nanocomposite modified GC electrode for electro-oxidation of benzene in natural water. - Graphical abstract: Display Omitted - Highlights: • A novel methodology for the electrochemical degradation of benzene was developed. • Sensor based on silver nanoparticle-decorated carbon nanotubes was used. • The proposed method is suitable and efficient for the removal of benzene

  19. Biodegradation of high concentrations of benzene vapors in a two phase partition stirred tank bioreactor

    Directory of Open Access Journals (Sweden)

    Karimi Ali

    2013-01-01

    Full Text Available Abstract The present study examined the biodegradation rate of benzene vapors in a two phase stirred tank bioreactor by a bacterial consortium obtained from wastewater of an oil industry refinery house. Initially, the ability of the microbial consortium for degrading benzene was evaluated before running the bioreactor. The gaseous samples from inlet and outlet of bioreactor were directly injected into a gas chromatograph to determine benzene concentrations. Carbone oxide concentration at the inlet and outlet of bioreactor were also measured with a CO2 meter to determine the mineralization rate of benzene. Influence of the second non-aqueous phase (silicon oil has been emphasized, so at the first stage the removal efficiency (RE and elimination capacity (EC of benzene vapors were evaluated without any organic phase and in the second stage, 10% of silicon oil was added to bioreactor media as an organic phase. Addition of silicon oil increased the biodegradation performance up to an inlet loading of 5580 mg/m3, a condition at which, the elimination capacity and removal efficiency were 181 g/m3/h and 95% respectively. The elimination rate of benzene increased by 38% in the presence of 10% of silicone oil. The finding of this study demonstrated that two phase partition bioreactors (TPPBs are potentially effective tools for the treatment of gas streams contaminated with high concentrations of poorly water soluble organic contaminant, such as benzene.

  20. Study of Humidity Effect on Benzene Decomposition by the Dielectric Barrier Discharge Nonthermal Plasma Reactor

    Science.gov (United States)

    Ma, Tianpeng; Zhao, Qiong; Liu, Jianqi; Zhong, Fangchuan

    2016-06-01

    The humidity effects on the benzene decomposition process were investigated by the dielectric barrier discharge (DBD) plasma reactor. The results showed that the water vapor played an important role in the benzene oxidation process. It was found that there was an optimum humidity value for the benzene removal efficiency, and at around 60% relative humidity (RH), the optimum benzene removal efficiency was achieved. At a SIE of 378 J/L, the removal efficiency was 66% at 0% RH, while the removal efficiency reached 75.3% at 60% RH and dropped to 69% at 80% RH. Furthermore, the addition of water inhibited the formation of ozone and NO2 remarkably. Both of the concentrations of ozone and NO2 decreased with increasing of the RH at the same specific input energy. At a SIE of 256 J/L, the concentrations of ozone and NO2 were 5.4 mg/L and 1791 ppm under dry conditions, whereas they were only 3.4 mg/L and 1119 ppm at 63.5% RH, respectively. Finally, the outlet gas after benzene degradation was qualitatively analyzed by FT-IR and GC-MS to determine possible intermediate byproducts. The results suggested that the byproducts in decomposition of benzene primarily consisted of phenol and substitutions of phenol. Based on these byproducts a benzene degradation mechanism was proposed. supported by National Natural Science Foundation of China (Nos. 11205007 and 11205029)

  1. Benzene derivatives adsorbed to the Ag(111) surface: Binding sites and electronic structure

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Daniel P.; Tymińska, Nina; Zurek, Eva, E-mail: ezurek@buffalo.edu [Department of Chemistry, State University of New York at Buffalo, Buffalo, New York 14260-3000 (United States); Simpson, Scott [Department of Chemistry, State University of New York at Buffalo, Buffalo, New York 14260-3000 (United States); School of Science, Penn State Erie, The Behrend College, 4205 College Drive, Erie, Pennsylvania 16563 (United States)

    2015-03-14

    Dispersion corrected Density Functional Theory calculations were employed to study the adsorption of benzenes derivatized with functional groups encompassing a large region of the activated/deactivated spectrum to the Ag(111) surface. Benzenes substituted with weak activating or deactivating groups, such as methyl and fluoro, do not have a strong preference for adsorbing to a particular site on the substrate, with the corrugations in the potential energy surface being similar to those of benzene. Strong activating (N(CH{sub 3}){sub 2}) and deactivating (NO{sub 2}) groups, on the other hand, possess a distinct site preference. The nitrogen in the former prefers to lie above a silver atom (top site), but in the latter a hollow hexagonal-closed-packed (H{sub hcp}) site of the Ag(111) surface is favored instead. Benzenes derivatized with classic activating groups donate electron density from their highest occupied molecular orbital to the surface, and those functionalized with deactivating groups withdraw electron density from the surface into orbitals that are unoccupied in the gas phase. For benzenes functionalized with two substituents, the groups that are strongly activating or deactivating control the site preference and the other groups assume sites that are, to a large degree, dictated by their positions on the benzene ring. The relative stabilities of the ortho, meta, and para positional isomers of disubstituted benzenes can, in some cases, be modified by adsorption to the surface.

  2. Electrochemical degradation of benzene in natural water using silver nanoparticle-decorated carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Cesarino, Ivana, E-mail: ivana@iqsc.usp.br [Instituto de Química de São Carlos, Universidade de São Paulo, C.P. 780, 13560-970, São Carlos, SP (Brazil); Cesarino, Vivian; Moraes, Fernando C.; Ferreira, Tanare C.R.; Lanza, Marcos R.V. [Instituto de Química de São Carlos, Universidade de São Paulo, C.P. 780, 13560-970, São Carlos, SP (Brazil); Mascaro, Lucia H. [Departamento de Química, Universidade Federal de São Carlos, C.P. 676, 13560-970, São Carlos, SP (Brazil); Machado, Sergio A.S. [Instituto de Química de São Carlos, Universidade de São Paulo, C.P. 780, 13560-970, São Carlos, SP (Brazil)

    2013-08-15

    In this study, a novel methodology for the electrochemical degradation of benzene in natural water using silver nanoparticle-decorated carbon nanotubes has been investigated. The morphology, the structure, and the electrochemical performance of the multi-walled carbon nanotubes-silver (MWCNT-Ag) nanocomposite film were characterised by transmission electron microscopy (TEM), X-ray diffraction (XRD), and cyclic voltammetry (CV), respectively. Electrocatalytic oxidation of benzene in an aqueous solution was studied to evaluate potential applications of the MWCNT-Ag modified glassy carbon (GC) electrode in environmental science. The benzene removal efficiency in natural water containing 10 mg L{sup −1} benzene yielded 77.9% at an applied potential of +2.0 V for 2 h using the MWCNT-Ag-GC electrode. In comparison, the removal efficiency reached only 8.0% with the bare GC electrode, showing the suitability of the MWCNT-Ag nanocomposite modified GC electrode for electro-oxidation of benzene in natural water. - Graphical abstract: Display Omitted - Highlights: • A novel methodology for the electrochemical degradation of benzene was developed. • Sensor based on silver nanoparticle-decorated carbon nanotubes was used. • The proposed method is suitable and efficient for the removal of benzene.

  3. Benzene derivatives adsorbed to the Ag(111) surface: Binding sites and electronic structure

    International Nuclear Information System (INIS)

    Dispersion corrected Density Functional Theory calculations were employed to study the adsorption of benzenes derivatized with functional groups encompassing a large region of the activated/deactivated spectrum to the Ag(111) surface. Benzenes substituted with weak activating or deactivating groups, such as methyl and fluoro, do not have a strong preference for adsorbing to a particular site on the substrate, with the corrugations in the potential energy surface being similar to those of benzene. Strong activating (N(CH3)2) and deactivating (NO2) groups, on the other hand, possess a distinct site preference. The nitrogen in the former prefers to lie above a silver atom (top site), but in the latter a hollow hexagonal-closed-packed (Hhcp) site of the Ag(111) surface is favored instead. Benzenes derivatized with classic activating groups donate electron density from their highest occupied molecular orbital to the surface, and those functionalized with deactivating groups withdraw electron density from the surface into orbitals that are unoccupied in the gas phase. For benzenes functionalized with two substituents, the groups that are strongly activating or deactivating control the site preference and the other groups assume sites that are, to a large degree, dictated by their positions on the benzene ring. The relative stabilities of the ortho, meta, and para positional isomers of disubstituted benzenes can, in some cases, be modified by adsorption to the surface

  4. The role of C-H$\\ldots$ interaction in the stabilization of benzene and adamantane clusters

    Indian Academy of Sciences (India)

    R Mahesh Kumar; M Elango; R Parthasarathi; Dolly Vijay; V Subramanian

    2012-01-01

    In this investigation, a systematic attempt has been made to understand the interaction between adamantane and benzene using both ab initio and density functional theory methods. C-H$\\ldots$ 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 former complex is stronger than the later. The diamondoid structure of adamantane enables it to interact with a maximum of four benzene molecules, each one along the four faces. The stability of the complex increases with increase in the number of benzene molecules. The energy decomposition analysis of adamantane-benzene complexes using DMA approach shows that the origin of the stability primarily arises from the dispersive interaction. The theory of atoms in molecules (AIM) supports the existence of weak interaction between the two systems. The electrostatic topography features provide clues for the mode of interaction of adamantane with benzene.

  5. Biodegradation of High Concentrations of Benzene Vapors in a Two Phase Partition Stirred Tank Bioreactor

    Directory of Open Access Journals (Sweden)

    Ali Karimi

    2013-01-01

    Full Text Available The present study examined the biodegradation rate of benzene vapors in a two phase stirred tank bioreactor by a bacterial consortium obtained from wastewater of an oil industry refinery house. Initially, the ability of the microbial consortium for degrading benzene was evaluated before running the bioreactor. The gaseous samples from inlet and outlet of bioreactor were directly injected into a gas chromatograph to determine benzene concentrations. Carbone oxide concentration at the inlet and outlet of bioreactor were also measured with a CO2 meter to determine the mineralization rate of benzene. Influence of the second non-aqueous phase (silicon oil has been emphasized, so at the first stage the removal efficiency (RE and elimination capacity (EC of benzene vapors were evaluated without any organic phase and in the second stage, 10% of silicon oil was added to bioreactor media as an organic phase. Addition of silicon oil increased the biodegradation performance up to an inlet loading of 5580?mg/m3, a condition at which, the elimination capacity and removal efficiency were 181?g/m3/h and 95% respectively. The elimination rate of benzene increased by 38% in the presence of 10% of silicone oil. The finding of this study demonstrated that two phase partition bioreactors (TPPBs are potentially effective tools for the treatment of gas streams contaminated with high concentrations of poorly water soluble organic contaminant, such as benzene.

  6. Occupational exposure to rubber vulcanization products during repair of rubber conveyor belts in a brown coal mine.

    Science.gov (United States)

    Gromiec, Jan P; Wesołowski, Wiktor; Brzeźnicki, Sławomir; Wróblewska-Jakubowska, Krystyna; Kucharska, Małgorzata

    2002-12-01

    Several hundred chemical compounds were found in workroom environments in the rubber industry, but most of the published exposure data relate to the production of tyres; information from the "non-tyre" sections are very limited, if any. This study was carried out to identify chemical substances and measure their air concentrations in the repair shop of a brown coal mine in which damaged rubber conveyor belts were repaired. GC-MS and HPLC analysis of stationary air samples resulted in identification of aliphatic and aromatic hydrocarbons to C12, PAHs, alcohols, phenols, ketones, heterocyclic nitrogen and sulfur compounds. Quantitative evaluation of occupational exposure included determination of organic compound vapours collected on charcoal (GC-MSD), polycyclic aromatic hydrocarbons (HPLC), N-nitrosoamines and other amines (GC-NPD) and DNPH derivatives of aldehydes (HPLC) in the breathing zone of workers representing all job titles. The concentrations of investigated compounds were very low. Carcinogenic substances: N-nitrosoamines, benzene, PAHs were not present in workroom air in concentrations exceeding limits of detection of the analytical methods being applied; concentrations of methylisobutylketone, tetrachloroethylene, naphtha, aromatic hydrocarbons, phthalates and aldehydes were much lower than the respective occupational exposure limit values. The results indicate much lower exposure than that reported in the production of tyres and other fabricated rubber products. PMID:12509065

  7. Benzene dispersion and natural attenuation in an alluvial aquifer with strong interactions with surface water

    Science.gov (United States)

    Batlle-Aguilar, Jordi; Brouyère, Serge; Dassargues, Alain; Morasch, Barbara; Hunkeler, Daniel; Höhener, Patrick; Diels, Ludo; Vanbroekhoven, Karolien; Seuntjens, Piet; Halen, Henri

    2009-05-01

    SummaryField and laboratory investigations have been conducted at a former coke plant, in order to assess pollutant attenuation in a contaminated alluvial aquifer, discharging to an adjacent river. Various organic (BTEX, PAHs, mineral oils) and inorganic (As, Zn, Cd) compounds were found in the aquifer in concentrations exceeding regulatory values. Due to redox conditions of the aquifer, heavy metals were almost immobile, thus not posing a major risk of dispersion off-site the brownfield. Field and laboratory investigations demonstrated that benzene, among organic pollutants, presented the major worry for off-site dispersion, mainly due to its mobility and high concentration, i.e. up to 750 mg L -1 in the source zone. However, benzene could never be detected near the river which is about 160 m downgradient the main source. Redox conditions together with benzene concentrations determined in the aquifer have suggested that degradation mainly occurred within 100 m distance from the contaminant source under anoxic conditions, and most probably with sulphate as main oxidant. A numerical groundwater flow and transport model, calibrated under transient conditions, was used to simulate benzene attenuation in the alluvial aquifer towards the Meuse River. The mean benzene degradation rate used in the model was quantified in situ along the groundwater flow path using compound-specific carbon isotope analysis (CSIA). The results of the solute transport simulations confirmed that benzene concentrations decreased almost five orders of magnitude 70 m downgradient the source. Simulated concentrations have been found to be below the detection limit in the zone adjacent to the river and consistent with the absence of benzene in downgradient piezometers located close to the river reported in groundwater sampling campaigns. In a transient model scenario including groundwater-surface water dynamics, benzene concentrations were observed to be inversely correlated to the river water

  8. Bond Energy Sums in Benzene, Cyclohexatriene and Cyclohexane Prove Resonance Unnecessary

    CERN Document Server

    Heyrovska, Raji

    2008-01-01

    The recent new structure of benzene shows that it consists of three C atoms of radii as in graphite alternating with three C atoms with double bond radii. This is different from the hypothetical cyclohexatriene (Kekule structure) involving alternate double and single bonds. It was shown that the difference in the bond energy sum of the atomic structure of benzene from that of the Kekule structure is the energy (erroneously) assumed to be due to resonance. Here it is shown that the present structure of benzene also explains the energy of hydrogenation into cyclohexane and its difference from that of cyclohexatriene.

  9. Survey of Recycled Nano Magnetic Particle in Benzene Removal from Aqueous Solution

    OpenAIRE

    Amin M.M.; Bina B.; Samani Majd A.M.; Pourzamani H.

    2013-01-01

    The removal of benzene, a hazardous monoaromatic compound, from aqueous solution by recycled nano magnetic particle (NM) Fe3O4 in batch condition was evaluated. Regeneration studies verified that the benzene adsorbed by the NM could be easily desorbed by temperature. So that the benzene removal effi-ciency was 98.7% for raw NM, 97.8% for first recycled NM and 97.4 percent for second recycled NM. It is expected that the Fe3O4 nanoparticles with fine grain size (20-30 nm) will be used as one of...

  10. 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.

  11. Pesticide exposure - Indian scene

    International Nuclear Information System (INIS)

    Use of pesticides in India began in 1948 when DDT was imported for malaria control and BHC for locust control. India started pesticide production with manufacturing plant for DDT and benzene hexachloride (BHC) (HCH) in the year 1952. In 1958, India was producing over 5000 metric tonnes of pesticides. Currently, there are approximately 145 pesticides registered for use, and production has increased to approximately 85,000 metric tonnes. Rampant use of these chemicals has given rise to several short-term and long-term adverse effects of these chemicals. The first report of poisoning due to pesticides in India came from Kerala in 1958 where, over 100 people died after consuming wheat flour contaminated with parathion. Subsequently several cases of pesticide-poisoning including the Bhopal disaster have been reported. Despite the fact that the consumption of pesticides in India is still very low, about 0.5 kg/ha of pesticides against 6.60 and 12.0 kg/ha in Korea and Japan, respectively, there has been a widespread contamination of food commodities with pesticide residues, basically due to non-judicious use of pesticides. In India, 51% of food commodities are contaminated with pesticide residues and out of these, 20% have pesticides residues above the maximum residue level values on a worldwide basis. It has been observed that their long-term, low-dose exposure are increasingly linked to human health effects such as immune-suppression, hormone disruption, diminished intelligence, reproductive abnormalities, and cancer. In this light, problems of pesticide safety, regulation of pesticide use, use of biotechnology, and biopesticides, and use of pesticides obtained from natural plant sources such as neem extracts are some of the future strategies for minimizing human exposure to pesticides

  12. A comparison of benzene, toluene and C{sub 2}-benzenes mixing ratios in automotive exhaust and in the suburban atmosphere during the introduction of catalytic converter technology to the Swiss Car Fleet

    Energy Technology Data Exchange (ETDEWEB)

    Heeb, N.V.; Forss, A.-M.; Bach, C.; Reimann, S.; Herzog, A.; Jackle, H.W. [Swiss Federal Laboratories for Materials Testing and Research, Duebendorf (Switzerland)

    2000-07-01

    Time-resolved chemical ionization mass spectrometry (CIMS) has been used to investigate the variations of the mixing ratios of benzene, toluene and the C{sub 2}-benzenes (xylenes and ethyl benzene) in automotive exhaust during transient engine operation. A significant increase of the benzene/toluene ratios from 0.35 to 1.31 (median) was found upon introduction of a catalytic converter system. A preliminary emission model was developed from these test stand measurements to simulate benzene/toluene ratios of passenger car fleets with variable proportions of three-way catalyst vehicles. Although only the emissions of gasoline-driven passenger cars have been considered so far, the predicted increase of the benzene/toluene ratios during the introduction period of the three-way catalyst from 1980 to 2000 is in good agreement with the observed increase of the atmospheric benzene/toluene ratio measured at a suburban monitoring site (Dubendorf, Switzerland) which is strongly influenced by road traffic emissions. At this site, the atmospheric concentrations of benzene and alkyl benzenes have been detected at hourly intervals since 1993. A steady decrease of the yearly mean from 3.54 to 2.00 ppb for toluene and from 2.87 to 1.33 ppb for the sum of C{sub 2}-benzenes was found from 1994 to 1998, respectively, when the proportion of three-way catalyst passenger cars increased from 60 to 82%. Nevertheless, the mean benzene concentration was only affected to a small degree (from 1.10 to 0.97 ppb) within the same period of time. Thus, the observed increase of the atmospheric benzene/toluene-mixing ratios from 0.32 to 0.58 (mean) is in good agreement with the predicted values from the presented emission model. Reduced catalyst conversion efficiency for benzene with respect to alkylated benzenes can explain most of the observed increase of the benzene/toluene and benzene/C{sub 2}-benzenes mixing rations. In addition, benzene emissions e.g. from the class of light duty vehicles, which

  13. A lack of consensus in the literature findings on the removal of airborne benzene by houseplants: Effect of bacterial enrichment

    Science.gov (United States)

    Sriprapat, Wararat; Strand, Stuart E.

    2016-04-01

    Removal rates of benzene and formaldehyde gas by houseplants reported by several laboratories varied by several orders of magnitude. We hypothesized that these variations were caused by differential responses of soil microbial populations to the high levels of pollutant used in the studies, and tested responses to benzene by plants and soils separately. Five houseplant species and tobacco were exposed to benzene under hydroponic conditions and the uptake rates compared. Among the test plants, Syngonium podophyllum and Chlorophytum comosum and Epipremnum aureum had the highest benzene removal rates. The effects of benzene addition on populations of soil bacteria were determined using reverse transcription quantitative PCR (RT-qPCR) assays targeting microbial genes involved in benzene degradation. The total bacterial population increased as shown by increases in the levels of eubacteria 16S rRNA, which was significantly higher in the high benzene incubations than in the low benzene incubations. Transcripts (mRNA) of genes encoding phenol monooxygenases, catechol-2,3-dioxygenase and the housekeeping gene rpoB increased in all soils incubated with high benzene concentrations. Therefore the enrichment of soils with benzene gas levels typical of experiments with houseplants in the literature artificially increased the levels of total soil bacterial populations, and especially the levels and activities of benzene-degrading bacteria.

  14. Collision lifetimes of polyatomic molecules at low temperatures: Benzene–benzene vs benzene–rare gas atom collisions

    International Nuclear Information System (INIS)

    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

  15. CH/pi interaction between benzene and hydrocarbons having six carbon atoms in their binary liquid mixtures.

    Science.gov (United States)

    Kasahara, Yasutoshi; Suzuki, Yuji; Kabasawa, Aino; Minami, Hideyuki; Matsuzawa, Hideyo; Iwahashi, Makio

    2010-01-01

    Molecular interactions between benzene and hydrocarbons having six carbon atoms, such as hexane, cyclohexane and 1-hexene in their binary liquid mixtures were studied through the measurements of density, viscosity, self-diffusion coefficient, (13)C NMR spin-lattice relaxation time and (1)H NMR chemical shift. CH/pi attraction between hexane and benzene in their binary mixture was observed in a relatively benzene rich region, whereas a special attractive interaction was not observed between cyclohexane and benzene. On the other hand, 1-hexene and benzene in their binary mixtures were characteristic in their self-diffusion coefficient behaviors: 1-hexene more strongly attract benzene not only by the CH/pi attraction but also probably by the p/p interaction between the double bond in 1-hexene and the p-electron in benzene ring. PMID:20032596

  16. 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

  17. Truncated Levy flights and agenda-based mobility are useful for the assessment of personal human exposure

    International Nuclear Information System (INIS)

    Receptor-oriented approaches can assess the individual-specific exposure to air pollution. In such an individual-based model we analyse the impact of human mobility to the personal exposure that is perceived by individuals simulated in an exemplified urban area. The mobility models comprise random walk (reference point mobility, RPM), truncated Levy flights (TLF), and agenda-based walk (RPMA). We describe and review the general concepts and provide an inter-comparison of these concepts. Stationary and ergodic behaviour are explained and applied as well as performance criteria for a comparative evaluation of the investigated algorithms. We find that none of the studied algorithm results in purely random trajectories. TLF and RPMA prove to be suitable for human mobility modelling, because they provide conditions for very individual-specific trajectories and exposure. Suggesting these models we demonstrate the plausibility of their results for exposure to air-borne benzene and the combined exposure to benzene and nonane. - Highlights: → Human exposure to air pollutants is influenced by a person's movement in the urban area. → We provide a simulation study of approaches to modelling personal exposure. → Agenda-based models and truncated Levy flights are recommended for exposure assessment. → The procedure is demonstrated for benzene exposure in an urban region. - Truncated Levy flights and agenda-based mobility are useful for the assessment of personal human exposure.

  18. Acute leukaemia after exposure to a weed killer, 2-methyl-4-chlorphenoxyacetic acid.

    Science.gov (United States)

    Timonen, T T; Palva, I P

    1980-01-01

    Acute leukaemia is known to develop in many cases of benzene-induced pancytopenia [1]. This is a report of the development of acute leukaemia in a patient who had apparently recovered from pancytopenia after chronic exposure to a weed killer, 2-methyl-4-chlorphenoxyacetic acid. PMID:6769284

  19. Occupational Exposure of Gasoline Station Workers to BTEX Compounds in Bangkok, Thailand

    Directory of Open Access Journals (Sweden)

    S Nopparatbundit

    2012-06-01

    Full Text Available Background: Gasoline station workers are exposed to volatile organic compounds such as benzene, toluene, ethylbenzene and xylene (BTEX. Objectives: To determine the level of exposure to BTEX compounds among gasoline station workers and measure the roadside concentrations of these compounds in the inner and outer areas of Bangkok, Thailand.Methods: 49 workers at 6 gasoline stations in the inner and outer areas of Bangkok participated in this study. Samples of ambient air were collected from the area near gas pumps at each station and at the roadside in front of the gas stations by charcoal tubes. All samples were analyzed for BTEX compounds by gas chromatography-flame ionized detector (GC-FID.Results: The mean BTEX concentration in gas stations was slightly higher than that of the roadside; there was no significant difference in the concentration between inner and outer areas. The mean lifetime cancer risks for workers exposed to benzene and ethylbenzene for 30 years were estimated at 1.75×10–4 and 9.55×10–7. The estimated hazard quotients for BTEX compounds were 0.600, 0.008, 0.007 and 0.002, respectively. The most prevalent symptoms of workers were headache (61%, fatigue (29% and throat irritation (11%, respectively. Exposure to benzene and toluene was significantly associated with fatigue (p<0.05.Conclusion: Exposure to BTEX compounds would increase the risk of cancer in gasoline station workers. Exposure to benzene and toluene may cause fatigue.

  20. BIOMarkers for occupational diesel exhaust exposure monitoring (BIOMODEM)--a study in underground mining

    DEFF Research Database (Denmark)

    Scheepers, P T J; Coggon, D; Knudsen, Lisbeth E.;

    2002-01-01

    mine in Estonia were compared with surface workers. Personal exposures to particle-associated 1-nitropyrene (NP) were some eight times higher underground than on the surface. Underground miners were also occupationally exposed to benzene and polycyclic aromatic hydrocarbons, as indicated by excretion...

  1. BIOMarkers for occupational diesel exhaust exposure monitoring (BIOMODEM) - a study in underground mining

    DEFF Research Database (Denmark)

    Scheepers, P.T.J.; Coggon, D.; Knudsen, Lisbeth E.;

    2002-01-01

    of urinary metabolites of benzene and pyrene. In addition, increased O6-alkylguanine DNA adducts were detected in the white blood cells of underground workers, suggesting higher exposure to nitroso-compounds. However, no differences between underground and surface workers were observed in the levels...

  2. Kinetics of Liquid-Phase Hydrogenation of Benzene in a Metal Hydride Slurry System Formed by M1Ni5 and Benzene

    Institute of Scientific and Technical Information of China (English)

    代世耀; 徐国华; 安越; 陈长聘; 陈立新; 王启东

    2003-01-01

    The kinetics of liquid-phase hydrogenation of benzene in misch metal nickel-five (M1Ni5) and benzene slurry system was studied by investigating the influences of the reaction temperature, pressure, alloy concentration and stirring speed on the mass transfer-reaction processes inside the slurry. The results show that the whole process is controlled by the reaction at the surface of the catalyst. The mass transfer resistance at gas-liquid interface and that from the bulk liquid phase to the surface of the catalyst particles are negligible. The apparent reaction rate is zero order for benzene concentration and first order for hydrogen concentration in the liquid phase. The kinetic model obtained fits the experimental data very well. The apparent activation energy of the hydrogen absorption reaction of M1Ni5-C6H6 slurry system is 42.16 kJ·mo1-1.

  3. Decomposition of benzene in air streams by UV/TiO2 process

    International Nuclear Information System (INIS)

    Photocatalytic decomposition of gaseous benzene at room temperature was studied with a fixed-bed annular reactor using titania as the photocatalyst. The effects of humidity, UV light intensity and benzene concentration on the conversion and mineralization of benzene were presented. Experimental results can be adequately described by using the Langmuir-Hinshelwood (L-H) kinetic model. The concentration distribution of benzene in the annular reactors of various dimensions can be described by combining the reactor design equation with L-H kinetics. Deactivation of catalyst was observed and attributed to the adsorption of reaction intermediates on TiO2 surface. The deactivated TiO2 catalyst could be photochemically regenerated by ozone-purging in the presence of humidity

  4. Very low-energy electron scattering from benzene: experiment and theory

    International Nuclear Information System (INIS)

    Low-energy collision studies have shown that the scattering cross section for electrons by benzene rises sharply at electron impact energies below ∼200 meV. This was attributed in earlier work to electron attachment and formation of benzene anions with lifetimes τ≥1 μs. A detailed study of electron attachment to benzene is reported here that makes use of Rydberg atom techniques. The data provide no evidence for the formation of long-lived benzene anions, although a small collisional ionization signal is observed which is consistent with the formation of short-lived excited anions (τ≤3 ps). An alternative explanation for the rapid rise in cross section at low energy is presented, based on ab initio scattering calculations. These calculations indicate that virtual state scattering takes place at low energies. Possible implications of this are briefly discussed. (author)

  5. DFT study of benzene and CO co-adsorption on PtCo(1 1 1)

    International Nuclear Information System (INIS)

    Co-adsorption of benzene and CO on PtCo(1 1 1) surface at low coverage is studied using density functional theory calculations. We investigated the PtCo FCT alloy surface with a uniform distribution. The most favorable site for CO is top on a Pt atom whereas for benzene is an HCP hollow site (formed by 2 Pt atoms and 1 Co atom). The co-adsorption energy is −1.62 eV. The calculations indicate a CO molecule with a ∼4° tilt angle with the normal to the surface. The most important bond is Pt-CCO, as revealed by overlap population analysis. A very small CO–benzene interaction is also detected. The vibrational frequencies of adsorbed benzene and CO were also computed.

  6. Benzene adsorption on PtCo(1 1 1): A DFT study

    International Nuclear Information System (INIS)

    Adsorption benzene on PtCo(1 1 1) surface at low coverage is investigated using density functional theory calculations. We have investigated the PtCo FCT alloy surface with a uniform distribution and two-benzene orientation on the surface. It was found that the most favorable site is a Co-Co bridge with an adsorption energy of −0.37 eV. A large buckling for the first Co and Pt atoms on the surface layers and a 17–30° H-tilt angles are found. The bonding analysis indicates that C-C and C-H bonding increase while Pt-Pt, Co-Co and Pt-Co decrease 13.2, 73 and 33%, respectively, after adsorption benzene. The vibrational frequencies of adsorbed benzene were also calculated.

  7. Desorption of silver atoms from benzene-covered Ag(1 1 1) by energetic Ar+ bombardment

    International Nuclear Information System (INIS)

    Experiments have been conducted to gain insight into the processes of desorption of neutral species from surfaces covered with organic molecules due to bombardment with keV particles. The system is comprised of benzene molecules adsorbed onto Ag(1 1 1) and bombarded with 8 keV Ar+ ions. Molecular dynamics (MD) simulations of the same system have been performed. Results show that the presence of the benzene alters the yield, the kinetic energy distributions, and the angular distributions of the silver atoms. These changes of the desorption characteristics are the result of collisions between the Ag atoms and the benzene molecules adsorbed to the surface. As more benzene is adsorbed to the surface, the changes to the Ag atom desorption characteristics become more pronounced. The simulations reproduce the modifications to the Ag atom energy and angle distributions

  8. Reverse isotope dilution method for determining benzene and metabolites in tissues

    Energy Technology Data Exchange (ETDEWEB)

    Bechtold, W.E.; Sabourin, P.J.; Henderson, R.F.

    1988-07-01

    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.

  9. Biomonitoring of benzene and toluene in human blood by headspace-solid-phase microextraction

    Energy Technology Data Exchange (ETDEWEB)

    Schimming, E.; Levsen, K. [Fraunhofer-Institut fuer Toxikologie und Aerosolforschung (ITA), Hannover (Germany); Koehme, C.; Schuermann, W. [Medizinische Hochschule Hannover (Germany). Abt. fuer Pneumologie

    1999-01-01

    A simple and rapid method for the determination of benzene and toluene in whole blood by headspace-solid-phase microextraction (HS-SPME) is described. Using SPME fibres coated with 65 {mu}m carboxene/polydimethylsiloxane, limits of quantification (LOQ) of 5 ng/L for benzene and 25 ng/L for toluene are achieved. As a result of its large linear range (i.e. 5-5000 ng/L for benzene) the method is suitable for biomonitoring of both occupationally and environmentally exposed people. The reproducibility of the determination of benzene is {<=} 8%. An interlaboratory comparison demonstrated that the method proposed here compares favorably with existing methods (dynamic headspace, purge and trap). (orig.) With 2 figs., 2 tabs., 10 refs.

  10. Prevention of benzene-induced myelotoxicity by nonsteroidal anti-inflammatory drugs

    Energy Technology Data Exchange (ETDEWEB)

    Kalf, G.F.; Schlosser, M.J.; Renz, J.F.; Pirozzi, S.J. (Jefferson Medical College of Thomas Jefferson Univ., Philadelphia, PA (USA))

    1989-07-01

    Benzene affects hematopoietic progenitor cells leading to bone marrow depression and genotoxic effects such as micronucleus formation. Progenitor cell proliferation and differentiation are inhibited by prostaglandins produced by macrophages. Administration of benzene to DBA/2 or C57BL/6 mice caused a dose-dependent bone marrow depression and a significant increase in marrow prostaglandin E level and both were prevented by the coadministration of indomethacin and other inhibitors of the cyclooxygenase component of prostaglandin H synthase. Levels of benzene that decreased bone marrow cellularity also caused genotoxic effects measured as increased micronucleated polychromatic erythrocytes in peripheral blood, which was also prevented by the coadministration of indomethacin. These results suggest a possible role for prostaglandin synthase in benzene myelotoxicity; a mechanism by which this might occur is presented.

  11. 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...... electron from the CH3X− 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...

  12. Hydrogen isotope exchange between boranes and deuterated aromatic hydrocarbons: evidence for reversible hydroboration of benzene

    International Nuclear Information System (INIS)

    Pentaborane, B5H9, and diborane, B2H6, undergo hydrogen isotope exchange with deuterated aromatic hydrocarbons. Lewis acid catalyzed hydrogen isotope exchange occurs between benzene-d6 and the apical hydrogen atom of B5H9 to form 1-DB5H8 at ambient temperature. In uncatalyzed exchanges, B5H9 reacts with deuterated aromatic hydrocarbons to produce 1,2,3,4,5-D5B5H4 at +450C and B5D9 at +1200C. This thermally induced hydrogen isotope exchange apparently occurs via a reversible hydroboration of the aromatic ring. Diborane undergoes a similar isotope exchange with benzene-d6 under mild thermal conditions. 18 references, 6 figures, 3 tables

  13. Experimental research on benzene detection using ion mobility spectrometer with a laser ionization source

    Institute of Scientific and Technical Information of China (English)

    LIU Xian-yun; KONG Xiang-he; JI Ren-dong; ZHANG Shu-dong

    2006-01-01

    An ion mobility spectrometer equipped with a laser ionization source is used for the sensitive detection of benzene.Mobility spectra of the benzene are presented.We also discussed the mobility spectra at various concentrations and drift voltages.Detection limits are determined to be in the upper ppbv range.In the end,the advantages and possibilities of this technique are briefly discussed.

  14. Biodegradation of mixtures of substituted benzenes by Pseudomonas sp. strain JS150.

    OpenAIRE

    Haigler, B E; Pettigrew, C A; Spain, J C

    1992-01-01

    Pseudomonas sp. strain JS150 was isolated as a nonencapsulated variant of Pseudomonas sp. strain JS1 that contains the genes for the degradative pathways of a wide range of substituted aromatic compounds. Pseudomonas sp. strain JS150 grew on phenol, ethylbenzene, toluene, benzene, naphthalene, benzoate, p-hydroxybenzoate, salicylate, chlorobenzene, and several 1,4-dihalogenated benzenes. We designed experiments to determine the conditions required for induction of the individual pathways and ...

  15. A system for the analysis of tritium content in natural waters, through benzene

    International Nuclear Information System (INIS)

    A system is described for the analysis of tritium (3H) 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)

  16. RPBE-vdW Description of Benzene Adsorption on Au(111)

    DEFF Research Database (Denmark)

    Pedersen, Jess Wellendorff; Kelkkanen, Kari André; Mortensen, Jens Jørgen;

    2010-01-01

    der Waals interactions. The adsorption of benzene on Au(111) is an often mentioned such system where standard density functionals predict a very weak adsorption or even a repulsion, whereas a significant adsorption is observed experimentally. We show that a considerable improvement in the description...... of the adsorption of benzene on Au(111) is obtained when using the so-called RPBE-vdW functional....

  17. Molecular simulation study on Hofmeister cations and the aqueous solubility of benzene.

    Science.gov (United States)

    Ganguly, Pritam; Hajari, Timir; van der Vegt, Nico F A

    2014-05-22

    We study the ion-specific salting-out process of benzene in aqueous alkali chloride solutions using Kirkwood-Buff (KB) theory of solutions and molecular dynamics simulations with different empirical force field models for the ions and benzene. Despite inaccuracies in the force fields, the simulations indicate that the decrease of the Setchenow salting-out coefficient for the series NaCl > KCl > RbCl > CsCl is determined by direct benzene-cation correlations, with the larger cations showing weak interactions with benzene. Although ion-specific aqueous solubilities of benzene may be affected by indirect ion-ion, ion-water, and water-water correlations, too, these correlations are found to be unimportant, with little to no effect on the Setchenow salting-out coefficients of the various salts. We further considered LiCl, which is experimentally known to be a weaker salting-out agent than NaCl and KCl and, therefore, ranks at an unusual position within the Hofmeister cation series. The simulations indicate that hydrated Li(+) ions can take part of the benzene hydration shell while the other cations are repelled by it. This causes weaker Li(+) exclusion around the solute and a resulting, weaker salting-out propensity of LiCl compared to that of the other salts. Removing benzene-water and benzene-salt electrostatic interactions in the simulations does not affect this mechanism, which may therefore also explain the smaller effect of LiCl, as compared to that of NaCl or KCl, on aqueous solvation and hydrophobic interaction of nonpolar molecules. PMID:24792435

  18. (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.

  19. BENZENE FORMATION ON INTERSTELLAR ICY MANTLES CONTAINING PROPARGYL ALCOHOL

    International Nuclear Information System (INIS)

    Propargyl alcohol (CHCCH2OH) is a known stable isomer of the propenal (CH2CHCHO) 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 (C6H6) formation to be the major product from propargyl alcohol irradiation, confirming the role of propargyl radicals (C3H3) formed from propargyl alcohol dissociation that was long expected based on theoretical modeling to effectively synthesize C6H6 in the interstellar icy mantles

  20. Vibrationally averaged dipole moments of methane and benzene isotopologues

    Science.gov (United States)

    Arapiraca, A. F. C.; Mohallem, J. R.

    2016-04-01

    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 C6H3D3 is about twice as large as the measured dipole moment of C6H5D. 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.

  1. Positronium formation and annihilation in BHDC/water/benzene microemulsions

    International Nuclear Information System (INIS)

    Positron lifetime measurements have been made on BHDC/water/benzene microemulsions, at different water to surfactant molar ratios (w0) and different surfactant concentrations (CBHDC). Recently, a model has been proposed to explain the positronium formation and annihilation in AOT/water/isooctane microemulsions, which states that the majority of positronium formation occurs in the aqueous cores of the reverse micelles, and the o-Ps there formed diffuses out of the aqueous cores into the organic solvent bulk. The BHDC based microemulsion system has been chosen in order to study the influence of the cationic head group and of the chloride counterion present in the aqueous pseudophase on the Ps formation probability and on the o-Ps diffusion out of the aqueous cores. The results of this study are satisfactorily explained by the referred model. The radii of the aqueous cores for different w0 values and calculated from the o-Ps lifetime measurements, are in good agreement with the values reported in the literature. The measured o-Ps intensities in both the aqueous pseudophase and the organic phase were found to be in agreement with those calculated by taking into account the partial inhibition due to the chloride counterions present in the aqueous cores. (orig.)

  2. 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.

  3. Multiple solutions of CCD equations for PPP model of benzene

    CERN Document Server

    Podeszwa, R; Jankowski, K; Rubiniec, K; Podeszwa, Rafa{\\l}; Stolarczyk, Leszek Z.; Jankowski, Karol; Rubiniec, Krzysztof

    2002-01-01

    To gain some insight into the structure and physical significance of the multiple solutions to the coupled-cluster doubles (CCD) equations corresponding to the Pariser-Parr-Pople (PPP) model of cyclic polyenes, complete solutions to the CCD equations for the A^{-}_{1g} states of benzene are obtained by means of the homotopy method. By varying the value of the resonance integral beta from -5.0 eV to -0.5 eV, we cover the so-called weakly, moderately, and strongly correlated regimes of the model. For each value of beta 230 CCD solutions are obtained. It turned out, however, that only for a few solutions a correspondence with some physical states can be established. It has also been demonstrated that, unlike for the standard methods of solving CCD equations, some of the multiple solutions to the CCD equations can be attained by means of the iterative process based on Pulay's direct inversion in the iterative subspace (DIIS) approach.

  4. Anaerobic degradation of alkylated benzenes in denitrifying laboratory aquifer columns

    International Nuclear Information System (INIS)

    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 14CO2 evolved from 14C-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

  5. Prolonged in vitro exposure of Staphylococcus aureus to germicidal teat dips.

    Science.gov (United States)

    Hogan, J S; Smith, K L

    1989-04-01

    Eight strains of Staphylococcus aureus were tested to determine if prolonged exposure to commercial teat dips could enhance bacterial tolerance to teat dips in vitro. All strains of S. aureus were serially plated 15 times on chemically defined agar medium containing sublethal concentrations of linear dodecyl benzene sulfonic acid, chlorhexidine, sodium hypochlorite, and iodophor teat dips. Growth responses of S. aureus to chlorhexidine, sodium hypochlorite, and iodophor were not affected by prolonged exposure to these teat dips. Isolates subcultured on agar containing .1% linear dodecyl benzene sulfonic acid teat dip subsequently had a greater mean growth response to .1% solution of the germicide than did controls subcultured on basal medium. Hemolytic patterns, tube coagulase, clumping factor, and protein A reactions of S. aureus were not altered by exposure to any of the teat dips tested. In general, prolonged exposure to commercial teat dips did not alter germicidal susceptibility of S. aureus. PMID:2745808

  6. Geogenic sources of benzene in aquifers used for public supply, California

    Science.gov (United States)

    Belitz, Kenneth; Landon, Matthew K.

    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.

  7. Protective effects of zinc and selenium against benzene toxicity in rats.

    Science.gov (United States)

    Ibrahim, Khadiga S; Saleh, Zeinab A; Farrag, Abdel-Razik H; Shaban, Eman E

    2011-07-01

    The presented study investigates the protective role of zinc (Zn) and selenium (Se) in attenuating benzene-induced toxicity in rats. Male Sprague-Dawley rats were injected with benzene (0.5 mL/kg body weight ip) and received a diet supplement containing Zn and Se. Several hematological and biochemical parameters (representing antioxidant status) were estimated. Histopathological examinations were performed. Results showed that food intake and body weight gain of benzene-injected rats were significantly lower than that of the control rats. Benzene-injected rats showed increased plasma malondialdehyde (MDA) and decreased activity of: glutathione peroxidase (GSH-Px), catalase, superoxide dismutase (SOD) enzymes, as well as reduced glutathione (GSH) when compared to the control group. Histopathological investigations revealed structural changes in benzene-injected rats' liver. Supplementation with Zn and Se resulted in a significant decrease in MDA, elevation in GSH, GSH-Px, SOD and catalase levels. This study shows that Zn and Se supplementation can improve the activity of antioxidant enzymes in rats and decrease the histological anomalies induced by benzene toxicity as well. PMID:21511895

  8. Consistent assignment of the vibrations of symmetric and asymmetric para-disubstituted benzene molecules

    Science.gov (United States)

    Andrejeva, Anna; Gardner, Adrian M.; Tuttle, William D.; Wright, Timothy G.

    2016-03-01

    We give a description of the phenyl-ring-localized vibrational modes of the ground states of the para-disubstituted benzene molecules including both symmetric and asymmetric cases. In line with others, we quickly conclude that the use of Wilson mode labels is misleading and ambiguous; we conclude the same regarding the related ones of Varsányi. Instead we label the modes consistently based upon the Mulliken (Herzberg) method for the modes of para-difluorobenzene (pDFB). Since we wish the labelling scheme to cover both symmetrically- and asymmetrically-substituted molecules, we apply the Mulliken labelling under C2v symmetry. By studying the variation of the vibrational wavenumbers with mass of the substituent, we are able to identify the corresponding modes across a wide range of molecules and hence provide consistent assignments. Particularly interesting are pairs of vibrations that evolve from in- and out-of-phase motions in pDFB to more localized modes in asymmetric molecules. We consider the para isomers of the following: the symmetric dihalobenzenes, xylene, hydroquinone, the asymmetric dihalobenzenes, halotoluenes, halophenols and cresol.

  9. Radiolytic investigations of solutions of organophosphorus compounds in cyclohexane and benzene

    International Nuclear Information System (INIS)

    Organphosphorus compounds are used in various branches of the chemical industry, but in many cases the reaction mechanisms are not well elucidated and less is known about the intermediates of organophosphines. In order to learn more about these rather complicated processes several organophosphorus compounds were used as model substrates in cyclohexane or benzene solution. The systems have been investigated applying the pulse radiolysis technique and steady-state irradiation methods. As representative solutes were chosen diphenylphosphinous chloride, diphenylmethylphosphine, and triphenylphosphine. By means of the pulse radiolysis it was possible to obtain spectroscopic and kinetic data for characterization of the various transients. The final radiolytic products have been analyzed following steady-state and multipulse radiolysis. Since some of the rate constants were not directly accessible by the applied kinetic method, they have been determined by simulation computation. Thereby the experimental data obtained by pulse radiolysis were used. Based on the kinetic, spectroscopic and computed data as well as on the identification of final products, it was possible to elucidate the reaction mechanism of the diphenylphosphinous chloride/cyclohexane system. As a main primary specie was identified the diphenylphoshorus radical. Its spectral and kinetic data have been determined. The reactions of diphenylmethylphosphine involve the same radical, but only to a lesser extent. The reactions of the primary radiolysis products with triphenylphosphine yield mainly adducts. The results represent a contribution in the field of reaction kinetics of organophosphorus compounds. (author)

  10. Direct hydroxylation of benzene to phenol - aspects of catalysts development and reaction kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Unger, A.; Hiemer, U.; Schwieger, W. [Lehrstuhl fuer Technische Chemie 1, Erlangen-Nuernberg, Erlangen (Germany); Reitzmann, A. [Inst. fuer Chemische Verfahrenstechnik (CVT), Karlsruhe Univ. (Germany); Klemm, E. [DEGUSSA AG, Service Unit Process Technology, Hanau-Wolfgang (Germany)

    2002-07-01

    An alternative route for phenol synthesis is the direct hydroxylation of benzene with nitrous oxide over zeolite catalysts of the ZSM5-type. The disadvantage of this pathway to phenol is the fact that a technically suitable catalyst is not yet available. This is due to low yields and fast deactivation behaviour of the presently-used catalysts. From a scientific point of view one has to state that the reaction mechanism of this single-step reaction is still not clear. The catalyst development requires a systematic study with respect to the chemical, structural and/or morphological properties of the catalytic materials that might have an influence on the performance of the catalyst and/or on the reaction itself. The chance to design the catalyst in a desired way is given by the large variety of parameters that can influence the properties of the zeolite during the synthesis itself or during following post-modification processes. Kinetic measurements offer the possibility to identify mechanism of the reaction and therefore allow conclusions for further improvements of the catalyst design and the reaction conditions itself. The combination of results of both research directions should open an opportunity to derive structure-activity relationships to provide a suitable catalyst for an industrial application. In the present paper we will show first results of an attempt following this described way. (orig.)

  11. Quantitative assessment of exposure and risk for three carcinogenics in long-standing pollution sites

    International Nuclear Information System (INIS)

    The project attempts a quantitative assessment of risks for three carcinogenics that are common in sites of long-standing pollution. Benzo(a)pyrene stands for the group of polycyclic aromatic hydrocarbons, cadmium for heavy metals, and benzene for volatile aromatic compounds. The report discusses the general fundamentals of exposure and risk assessment. The exposure model is described in detail and applied to the three test substances. (orig./MG)

  12. Study of the association between exposure to transuranic radionuclides and cancer death

    Science.gov (United States)

    Fallahian, Naz Afarin

    An exploratory epidemiological study has been conducted on 319 deceased nuclear workers, who had recorded intakes and histories of employment for at least one year during the time period from 1943 to 1995, at different facilities including the United States Department of Energy (DOE) sites, and thorium and uranium mining and milling plants. These workers voluntarily agreed to donate their organs or whole body to the United States Transuranium and Uranium Registries (USTUR) for scientific research purposes. The majority of this population was involved in documented radiological incidents during their careers. Many were exposed to transuranic radionuclides primarily via inhalation or puncture wounds. The purpose of this study was to find the level of dose that was received by the USTUR registrants following accidents and subsequent to mitigating actions, and to investigate whether or not there is any association between exposure to these transuranic radionuclides and cancer deaths. The external and internal dose assessments were performed using occupational radiation exposure histories and postmortem concentrations of transuranic radionuclides in critical organs, respectively. Statistical data analyses were performed to identify whether or not the USTUR registrants can be categorized as a 'low-dose' population and to investigate the potential correlation between exposure to transuranic radionuclides and causes of death within this population due to cancers of the lungs and liver as well as cancers of all sites, while controlling for the effects of other confounders. Based on the statistical tests performed, the USTUR registrants can be categorized as a low-dose population in terms of their occupational external exposures. However, when considering their total effective dose equivalents from both external penetrating radiation and internal exposure to transuranic radionuclides, they can not be categorized as a low-dose population with a 95% confidence level (alpha = 0

  13. Stress response, biotransformation effort, and immunotoxicity in captive birds exposed to inhaled benzene, toluene, nitrogen dioxide, and sulfur dioxide.

    Science.gov (United States)

    Cruz-Martinez, Luis; Smits, Judit E G; Fernie, Kim

    2015-02-01

    In the oil sands of Alberta, Canada, toxicology research has largely neglected the effects of air contaminants on biota. Captive Japanese quail (Coturnix c. japonica) and American kestrels (Falco sparverius) were exposed to mixtures of volatile organic compounds and oxidizing agents (benzene, toluene, NO2 and SO2) in a whole-body inhalation chamber, to test for toxicological responses. Hepatic biotransformation measured through 7-ethoxyresorufin-O-dealkylase (EROD) tended to be increased in exposed kestrels (p=0.06) but not in quail (p=0.15). Plasma corticosterone was increased in the low dose group for quail on the final day of exposure (p=0.0001), and midway through the exposure period in exposed kestrels (p=0.04). For both species, there was no alteration of T and B-cell responses, immune organ mass, or histology of immune organs (p>0.05). This study provides baseline information valuable to complement toxicology studies and provides a better understanding of potential health effects on wild avifauna. PMID:25463874

  14. Test of electron beam technology on Savannah River Laboratory low-activity aqueous waste for destruction of benzene, benzene derivatives, and bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Dougal, R.A. [Univ. of South Carolina, Columbia, SC (United States). Dept. of Electrical and Computer Engineering

    1993-08-01

    High energy radiation was studied as a means for destroying hazardous organic chemical wastes. Tests were conducted at bench scale with a {sup 60}Co source, and at full scale (387 l/min) with a 1.5 MV electron beam source. Bench scale tests for both benzene and phenol included 32 permutations of water quality factors. For some water qualities, as much as 99.99% of benzene or 90% of phenol were removed by 775 krads of {sup 60}Co irradiation. Full scale testing for destruction of benzene in a simulated waste-water mix showed loss of 97% of benzene following an 800 krad dose and 88% following a 500 krad dose. At these loss rates, approximately 5 Mrad of electron beam irradiation is required to reduce concentrations from 100 g/l to drinking water quality (5 {mu}g/l). Since many waste streams are also inhabited by bacterial populations which may affect filtering operations, the effect of irradiation on those populations was also studied. {sup 60}Co and electron beam irradiation were both lethal to the bacteria studied at irradiation levels far lower than were necessary to remove organic contaminants.

  15. Test of electron beam technology on Savannah River Laboratory low-activity aqueous waste for destruction of benzene, benzene derivatives, and bacteria

    International Nuclear Information System (INIS)

    High energy radiation was studied as a means for destroying hazardous organic chemical wastes. Tests were conducted at bench scale with a 60Co source, and at full scale (387 l/min) with a 1.5 MV electron beam source. Bench scale tests for both benzene and phenol included 32 permutations of water quality factors. For some water qualities, as much as 99.99% of benzene or 90% of phenol were removed by 775 krads of 60Co irradiation. Full scale testing for destruction of benzene in a simulated waste-water mix showed loss of 97% of benzene following an 800 krad dose and 88% following a 500 krad dose. At these loss rates, approximately 5 Mrad of electron beam irradiation is required to reduce concentrations from 100 g/l to drinking water quality (5 μg/l). Since many waste streams are also inhabited by bacterial populations which may affect filtering operations, the effect of irradiation on those populations was also studied. 60Co and electron beam irradiation were both lethal to the bacteria studied at irradiation levels far lower than were necessary to remove organic contaminants

  16. Survey results of benzene in soft drinks and other beverages by headspace gas chromatography/mass spectrometry.

    Science.gov (United States)

    Nyman, Patricia J; Diachenko, Gregory W; Perfetti, Gracia A; McNeal, Timothy P; Hiatt, Michael H; Morehouse, Kim M

    2008-01-23

    Benzene, a carcinogen that can cause cancer in humans, may form at nanogram per gram levels in some beverages containing both benzoate salts and ascorbic or erythorbic acids. Through a series of reactions, a hydroxyl radical forms that can decarboxylate benzoate to form benzene. Elevated temperatures and light stimulate these reactions, while sugar and ethylenediaminetetraacetic acid (EDTA) can inhibit them. A headspace gas chromatography/mass spectrometry method for the determination of benzene in beverages was developed and validated. The method was used to conduct a survey of 199 soft drinks and other beverages. The vast majority of beverages sampled contained either no detectable benzene or levels below the U.S. Environmental Protection Agency's drinking water limit of 5 ng/g. Beverages found to contain 5 ng/g benzene or more were reformulated by the manufacturers. The amount of benzene found in the reformulated beverages ranged from none detected to 1.1 ng/g. PMID:18072742

  17. Biodegradation of methane, benzene, and toluene by a consortium MBT14 enriched from a landfill cover soil.

    Science.gov (United States)

    Lee, Eun-Hee; Park, Hyunjung; Cho, Kyung-Suk

    2013-01-01

    In this study, landfill cover soil was used as an inoculum source to enrich a methane, benzene, and toluene-degrading consortium MBT14. Under a single substrate, the maximum degradation rates of methane, benzene and toluene were 1.96, 0.15, and 0.77 mmole g-DCW(-1) h(-1), respectively. Although the coexistence of benzene and toluene inhibited the methane degradation rates, the consortium was able to simultaneously degrade methane, benzene and toluene. Methane had an insignificant effect on benzene or toluene degradation. Based on 16S rDNA sequencing analysis, Cupriavidus spp. are dominant in the consortium MBT14. The combined results of this study indicate that the consortium MBT 14 is a promising bioresource for removing CH(4), benzene, and toluene from a variety of environments. PMID:23245302

  18. Separation of several alcohol-benzene mixtures by pervaporation through styrene graft polyethylene membranes

    International Nuclear Information System (INIS)

    The permeation of pure liquids, such as methanol, ethanol, 1-propanol, 2-propanol and benzene, and the permeability and selectivity of 50 vol% binary mixtures of these alcohols and benzene were investigated by pervaporation technique. The used membranes (21%, 40%, and 72% graftings) were obtained by graft polymerization of styrene to polyethylene film (thickness 10 μm) by γ-radiation. The permeation rates of each of these alcohols and benzene were measured by pervaporation through the graft membranes. Those of these alcohols were very small as well as those through the original membrane. On the other hand, the permeabilities for benzene through the graft membranes were larger than that through the original membrane. The temperature dependence of the permeation rate for benzene was expressed by Arrhenius-type relationships, and the apparent activation energies were calculated to be 10.7 (21%), 10.2 (40%) and 10.0 (72%) kcal/mol. In the permeation of 50 vol% several alcohol-benzene mixtures, the permeabilities through the graft membranes were also larger than that through the original membrane, and increased with the grafting. The temperature dependence of the permeation for these mixtures was showed by Arrhenius relationships, and the apparent activation energies were calculated to be in the range of 8.4∼11.0 kcal/mol. The separation factors of the graft membranes calculated from composition of the permeates were always smaller than that of the original membrane, but became larger with increase of molecular volume of alcohol in alcohol-benzene mixtures. (author)

  19. Bioremediation of benzene-, MTBE- and ammonia-contaminated groundwater with pilot-scale constructed wetlands

    International Nuclear Information System (INIS)

    In this pilot-scale constructed wetland (CW) study for treating groundwater contaminated with benzene, MTBE, and ammonia-N, the performance of two types of CWs (a wetland with gravel matrix and a plant root mat) was investigated. Hypothesized stimulative effects of filter material additives (charcoal, iron(III)) on pollutant removal were also tested. Increased contaminant loss was found during summer; the best treatment performance was achieved by the plant root mat. Concentration decrease in the planted gravel filter/plant root mat, respectively, amounted to 81/99% for benzene, 17/82% for MTBE, and 54/41% for ammonia-N at calculated inflow loads of 525/603 mg/m2/d, 97/112 mg/m2/d, and 1167/1342 mg/m2/d for benzene, MTBE, and ammonia-N. Filter additives did not improve contaminant depletion, although sorption processes were observed and elevated iron(II) formation indicated iron reduction. Bacterial and stable isotope analysis provided evidence for microbial benzene degradation in the CW, emphasizing the promising potential of this treatment technique. - Highlights: → BTEX compounds contaminated groundwater can be efficiently treated by CWs. → The removal efficiency depended on CW type, season and contaminant. → The plant root mat revealed better treatment results than the gravel filter CW. → Best results achieved by the plant root mat (99% benzene concentration decrease). → Stable isotope analysis and MPN indicated high benzene remediation potential. - Gravel bed constructed wetlands and a plant root mat system efficiently eliminated fuel hydrocarbons (benzene, MTBE) and ammonia-N from groundwater at a pilot-scale.

  20. Effect of benzene on product evolution in a H2S/O2 flame under Claus condition

    International Nuclear Information System (INIS)

    Highlights: • Effect of trace amounts of benzene (0.3%, 0.5% and 1%) to H2S combustion process. • Benzene favored formation of H2 and reduced conversion of H2S. • Benzene reduced SO2 formation to impact sulfur production. • Benzene addition promoted CO and COS formation and degraded sulfur quality. - Abstract: Experimental results are presented on the role of benzene addition to H2S combustion at an equivalence ratio of three with respect to H2S (Claus condition) and complete combustion of benzene. The results are reported with 0.3%, 0.5% and 1% benzene addition to H2S/O2 flame. Combustion of H2S and benzene mixtures is of practical value for sulfur recovery during combustion of acid gases. The results showed that H2S combustion caused H2S to decompose to a minimum mole fraction with high conversion of H2S while the SO2 mole fraction reached a maximum value. Addition of benzene decreased the conversion of H2S with reduced mole fraction of SO2 in the reactor to subsequently reduce the formation of elemental sulfur. Benzene also caused significant production of H2, CO and COS formation along with faster decomposition of the formed SO2. Presence of benzene, even in trace amounts, in acid gas hinders sulfur conversion in a Claus reactor and increases emission of unwanted sulfur bearing compounds. Increased hydrogen production with benzene offers potential value for hydrogen recovery under certain conditions

  1. Contaminant exposure in terrestrial vertebrates

    International Nuclear Information System (INIS)

    Here we review mechanisms and factors influencing contaminant exposure among terrestrial vertebrate wildlife. There exists a complex mixture of biotic and abiotic factors that dictate potential for contaminant exposure among terrestrial and semi-terrestrial vertebrates. Chemical fate and transport in the environment determine contaminant bioaccessibility. Species-specific natural history characteristics and behavioral traits then play significant roles in the likelihood that exposure pathways, from source to receptor, are complete. Detailed knowledge of natural history traits of receptors considered in conjunction with the knowledge of contaminant behavior and distribution on a site are critical when assessing and quantifying exposure. We review limitations in our understanding of elements of exposure and the unique aspects of exposure associated with terrestrial and semi-terrestrial taxa. We provide insight on taxa-specific traits that contribute, or limit exposure to, transport phenomenon that influence exposure throughout terrestrial systems, novel contaminants, bioavailability, exposure data analysis, and uncertainty associated with exposure in wildlife risk assessments. Lastly, we identify areas related to exposure among terrestrial and semi-terrestrial organisms that warrant additional research. - Both biotic and abiotic factors determine chemical exposure for terrestrial vertebrates

  2. Surgical Exposure

    OpenAIRE

    Hendra Chandra

    2015-01-01

    Surgical exposure is a surgical method to expose mucous or bone which prevent delayed or unerupted permanent crown teeth, in order to provide normal eruption and to prevent malocclusion. Surgical exposure is usually carried out on maxillary caninces as they have higher incidence of delayed eruption. Nevertheless, this procedure can also be performed on other teeth. For patient management, this procedure need cooperation betweent oral surgeon and orthodontist.

  3. EXCOMP: an exposure comparison methodology

    International Nuclear Information System (INIS)

    EXCOMP is a computerized model that was developed to project occupational exposures based on conceptual designs for the Monitored Retrievable Storage (MRS) Facility. EXCOMP was developed to identify locations and operations in the facility that have a potential for significant occupational exposure rates. Unlike the computerized models that are currently used, EXCOMP is fast and provides the analyst more analysis flexibility. The analyst has the option of evaluating the occupational exposures for an entire facility, specific work locations, personnel profiles based on employees' job descriptions, or the exposure potential of specific identified sources. Comparative analyses can be performed rapidly by initially analyzing the occupational exposures for a facility or a personnel profile and then modifying the database for selected specific work or source locations. EXCOMP was developed to provide the analyst a took that can be used to perform integrated facility evaluations of occupational and public exposures. EXCOMP provides estimates of exposure rates for the purpose of identifying areas with high exposure potential. These areas can be further evaluated using existing detailed exposure modeling computer codes or by performing ''hands on'' monitoring

  4. Isolated benzene and dichlorobenzene on the Ge(1 0 0)-c(4 × 2) surface

    International Nuclear Information System (INIS)

    Adsorption of isolated benzene and dichlorobenzene molecules on the Ge(1 0 0) surface is studied based on total energy and electronic structure density functional theory calculations. It is found that the most stable configuration for benzene on Ge(1 0 0) is the symmetric on-top single dimer bonding structure, with the asymmetric tight bridge configuration being the second lowest energy geometry. This is in contrast to benzene on Si(1 0 0) where the asymmetric tight bridge structure is the most stable structure. For dichlorobenzene on Ge(1 0 0) it is found that the on-top single dimer bonding structure is the most stable. We also show that while the stability of the adsorbed dichlorobenzene is significantly enhanced with respect to the adsorbed benzene on Ge(1 0 0), presumably due to the presence of the chlorine atoms, its electronic structure is similar to that in the gas phase. The latter was found to be similar to the weakly interacting benzene molecule with Ge(1 0 0).

  5. Thermal behaviors and grafting process of LDH/benzene derivative hybrid systems

    International Nuclear Information System (INIS)

    Highlights: ► Orientation of the organic entities between the layers of the mineral network. ► Influence of the organics functional group on the stability of the hybrid material. ► Demonstration of three different behaviors in terms of the grafting process. - Abstract: Thermal behaviors of four hybrid layered double hydroxide (LDH) phases have been studied by thermogravimetric analyses coupled with mass spectroscopy, temperature dependence of X-ray powder diffraction measurements, and temperature dependence of infrared spectroscopy measurements. Inorganic zinc–aluminium LDH main layers (with a Zn2+/Al3+ cationic ratio of 2) inserted the following four organic anions: benzene carboxylate, 4-hydroxy-benzene carboxylate, benzene sulfonate and 4-hydroxy-benzene sulfonate. The four LDH hybrids have been synthesized by the coprecipitation method. The as-prepared samples have been characterized and their compositions were determined. Thermal evolution of the crystalline phases during the dehydration (occurring before 200 °C) and the dehydroxylation (occurring between 200 and 300 °C) gave evidence for organic anion grafting onto the inorganic main layer. The thermal stability of the LDH hybrid system depends on the nature of the intercalated aromatic anion. The thermal grafting process can be monitored, as well as its thermal reversibility, by choosing the functionalizations of the benzenic anion and the temperature of the applied heat treatment.

  6. THE INFLUENCE OF BENZENE AS A TRACE REACTANT IN TITAN AEROSOL ANALOGS

    International Nuclear Information System (INIS)

    Benzene has been detected in Titan's atmosphere by Cassini instruments, with concentrations ranging from sub-ppb in the stratosphere to ppm in the ionosphere. Sustained levels of benzene in the haze formation region could signify that it is an important reactant in the formation of Titan's organic aerosol. To date, there have not been laboratory investigations to assess the influence of benzene on aerosol properties. We report a laboratory study on the chemical composition of organic aerosol formed from C6H6/CH4/N2 via far ultraviolet irradiation (120-200 nm). The compositional results are compared to those from aerosol generated by a more ''traditional Titan'' mixture of CH4/N2. Our results show that even a trace amount of C6H6 (10 ppm) has significant impact on the chemical composition and production rates of organic aerosol. There are several pathways by which photolyzed benzene may react to form larger molecules, both with and without the presence of CH4, but many of these reaction mechanisms are only beginning to be explored for the conditions at Titan. Continued work investigating the influence of benzene in aerosol growth will advance understanding of this previously unstudied reaction system.

  7. Theoretical investigation on the interaction between beryllium, magnesium and calcium with benzene, coronene, cirumcoronene and graphene

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • The binding energies between benzene and Be, Mg and Ca are 1.8, 2.3 and 3.2 kcal/mol. • The alkaline earth complexes with benzene favor the non ionic configuration. • For these complexes charge transfer does not take place. • The performance of the DFT functionals assayed was poor. - Abstract: The interaction energies (IE) between benzene and beryllium, magnesium and calcium were calculated at the CCSD(T)/CBS level and including corrections for core-valence and relativistic effects. The IE are 1.8, 2.3 and 3.2 kcal/mol for Be, Mg and Ca, respectively, In contrast with our previous findings for the benzene–Li complex, we found that the non-ionic structure is more stable than the ionic configuration. Thus, charge-transfer from alkaline earths to benzene would not take place. The performance of MP2 and DFT functionals is poor. At the complete basis set limit, M06-2X, M06-L, B97D and MP2 exhibited similar MAD (∼ 0.7–0.8 kcal/mol). When larger aromatic models were considered, the IE were similar to those computed for benzene. Finally, taking into account the drawbacks of the DFT functionals, the computed IE for the non-ionic adsorption of Be, Mg and Ca onto graphene, are tentatively estimated as 2.1, 2.7 and 2.9 kcal/mol, respectively

  8. Au/ZnO nanocomposites: Facile fabrication and enhanced photocatalytic activity for degradation of benzene

    International Nuclear Information System (INIS)

    Au nanoparticles supported on highly uniform one-dimensional ZnO nanowires (Au/ZnO hybrids) have been successfully fabricated through a simple wet chemical method, which were first used for photodegradation of gas-phase benzene. Compared with bare ZnO nanowires, the as-prepared Au/ZnO hybrids were found to possess higher photocatalytic activity for degradation of benzene under UV and visible light (degradation efficiencies reach about 56.0% and 33.7% after 24 h under UV and visible light irradiation, respectively). Depending on excitation happening on ZnO semiconductor or on the surface plasmon band of Au, the efficiency and operating mechanism are different. Under UV light irradiation, Au nanoparticles serve as an electron buffer and ZnO nanowires act as the reactive sites for benzene degradation. When visible light is used as the light irradiation source, Au nanoparticles act as the light harvesters and photocatalytic sites alongside of charge-transfer process, simultaneously. -- Graphical abstract: Under visible light irradiation, Au nanoparticles, which are supported on ZnO nanowires, dominate their catalytic properties in gas-phase degradation benzene reaction. Highlights: ► The composites that Au nanoparticles supported on ZnO nanowires were synthesized. ► Au/ZnO composites were firstly used as effective photocatalysts for benzene degradation. ► Two operating mechanisms were proposed depending on excitation wavelength.

  9. Hydrogen-terminated silicon nanowire photocatalysis: Benzene oxidation and methyl red decomposition

    International Nuclear Information System (INIS)

    Graphical abstract: H-SiNWs can catalyze hydroxylation of benzene and degradation of methyl red under visible light irradiation. Highlights: ► Hydrogen-terminated silicon nanowires were active photocatalyst in the hydroxylation of benzene under light. ► Hydrogen-terminated silicon nanowires were also effective in the decomposition of methyl red dye. ► The Si/SiOx core-shell structure is the main reason of the obtained high selectivity during the hydroxylation. -- Abstract: Hydrogen-terminated silicon nanowires (H-SiNWs) were used as heterogeneous photocatalysts for the hydroxylation of benzene and for the decomposition of methyl red under visible light irradiation. The above reactions were monitored by GC–MS and UV–Vis spectrophotometry, respectively, which shows 100% selectivity for the transformation of benzene to phenol. A complete decomposition of a 2 × 10−4 M methyl red solution was achieved within 30 min. The high selectivity for the hydroxylation of benzene and the photodecomposition demonstrate the catalytic activity of ultrafine H-SiNWs during nanocatalysis.

  10. Au/ZnO nanocomposites: Facile fabrication and enhanced photocatalytic activity for degradation of benzene

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Hang; Ming, Hai; Zhang, Hengchao; Li, Haitao; Pan, Keming [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 (China); Liu, Yang, E-mail: yangl@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 (China); Wang, Fang; Gong, Jingjing [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 (China); Kang, Zhenhui, E-mail: zhkang@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou 215123 (China)

    2012-11-15

    Au nanoparticles supported on highly uniform one-dimensional ZnO nanowires (Au/ZnO hybrids) have been successfully fabricated through a simple wet chemical method, which were first used for photodegradation of gas-phase benzene. Compared with bare ZnO nanowires, the as-prepared Au/ZnO hybrids were found to possess higher photocatalytic activity for degradation of benzene under UV and visible light (degradation efficiencies reach about 56.0% and 33.7% after 24 h under UV and visible light irradiation, respectively). Depending on excitation happening on ZnO semiconductor or on the surface plasmon band of Au, the efficiency and operating mechanism are different. Under UV light irradiation, Au nanoparticles serve as an electron buffer and ZnO nanowires act as the reactive sites for benzene degradation. When visible light is used as the light irradiation source, Au nanoparticles act as the light harvesters and photocatalytic sites alongside of charge-transfer process, simultaneously. -- Graphical abstract: Under visible light irradiation, Au nanoparticles, which are supported on ZnO nanowires, dominate their catalytic properties in gas-phase degradation benzene reaction. Highlights: Black-Right-Pointing-Pointer The composites that Au nanoparticles supported on ZnO nanowires were synthesized. Black-Right-Pointing-Pointer Au/ZnO composites were firstly used as effective photocatalysts for benzene degradation. Black-Right-Pointing-Pointer Two operating mechanisms were proposed depending on excitation wavelength.

  11. Incense, sparklers and cigarettes are significant contributors to indoor benzene and particle levels

    Directory of Open Access Journals (Sweden)

    Werner Tirler

    2015-03-01

    Full Text Available Introduction. The increased use of incense, magic candles and other flameless products often produces indoor pollutants that may represent a health risk for humans. Today, in fact, incense and air fresheners are used inside homes as well as in public places including stores, shopping malls and places of worship. As a source of indoor contamination, the impact of smoke, incense and sparklers on human health cannot be ignored. Aim. In the present work, we report the results of an emission study regarding particles (PM10 and particle number concentration, PNC and benzene, produced by various incense sticks and sparklers. Results and discussion.The results obtained for benzene, PM10 and PNC, showed a strong negative influence on air quality when these products were used indoors. Various incense sticks gave completely different benzene results: from a small increase of the benzene concentration in the air, just slightly above the background levels of ambient air, to very high concentrations, of more than 200 µg/m³ of benzene in the test room after the incense sticks had been tested.

  12. Gaseous phase benzene decomposition by non-thermal plasma coupled with nano titania catalyst

    International Nuclear Information System (INIS)

    Synergistic effect of atmospheric non-thermal plasma generated by dielectric barrier discharge and nano titania photo catalyst for benzene decomposition was tested. The paper indicated the effect of photo catalyst on removal efficiency of benzene, the compare of photo catalyst characteristic in different high temperatures by heat treatment, analysis of by-products. The results showed that the effect of degradation was visible by added photo catalyst in the plasma reactor. When concentration of benzene was 600 mg/m3 and electric field strength was 10 kV/cm, the removal efficiency of benzene was increased up to 81 % without photo catalyst. At the same condition, the removal efficiency was increased to 15 % higher with photo catalyst. Nano titania crystal was anatase crystal in 450 degC heat treatment which is best for benzene removal. The plasma reactor packed with photo catalyst shows a better selectivity of carbon dioxide than that without photo catalyst. By-products are mostly carbon dioxide, water and a small quantity of carbon monoxide

  13. THE INFLUENCE OF BENZENE AS A TRACE REACTANT IN TITAN AEROSOL ANALOGS

    Energy Technology Data Exchange (ETDEWEB)

    Trainer, Melissa G. [Planetary Environments Laboratory, Code 699, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Sebree, Joshua A. [NASA Postdoctoral Program Fellow, Code 699, Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Heidi Yoon, Y.; Tolbert, Margaret A., E-mail: melissa.trainer@nasa.gov [Cooperative Institute for Research in Environmental Sciences, University of Colorado at Boulder, Box 216 UCB, Boulder, CO 80309 (United States)

    2013-03-20

    Benzene has been detected in Titan's atmosphere by Cassini instruments, with concentrations ranging from sub-ppb in the stratosphere to ppm in the ionosphere. Sustained levels of benzene in the haze formation region could signify that it is an important reactant in the formation of Titan's organic aerosol. To date, there have not been laboratory investigations to assess the influence of benzene on aerosol properties. We report a laboratory study on the chemical composition of organic aerosol formed from C{sub 6}H{sub 6}/CH{sub 4}/N{sub 2} via far ultraviolet irradiation (120-200 nm). The compositional results are compared to those from aerosol generated by a more ''traditional Titan'' mixture of CH{sub 4}/N{sub 2}. Our results show that even a trace amount of C{sub 6}H{sub 6} (10 ppm) has significant impact on the chemical composition and production rates of organic aerosol. There are several pathways by which photolyzed benzene may react to form larger molecules, both with and without the presence of CH{sub 4}, but many of these reaction mechanisms are only beginning to be explored for the conditions at Titan. Continued work investigating the influence of benzene in aerosol growth will advance understanding of this previously unstudied reaction system.

  14. occupational exposure to aromatic hydrocarbons at a coke plant: Part II. Exposure assessment of volatile organic compounds.

    Science.gov (United States)

    Bieniek, Grazyna; Kurkiewicz, Slawomir; Wilczok, Tadeusz; Klimek, Katarzyna; Swiatkowska, Longina; Lusiak, Agnieszka

    2004-05-01

    The objective of the study is to assess the external and internal exposures to aromatic hydrocarbons in the tar and oil naphthalene distillation processes at a coke plant. 69 workers engaged as operators in tar and oil naphthalene distillation processes and 25 non-exposed subjects were examined. Personal analyses of the benzene, toluene, xylene isomers, ethylbenzene, naphthalene, indan, indene and acenaphthene in the breathing zone air allowed us to determine the time weighted average exposure levels to the aromatic hydrocarbons listed above. The internal exposure was investigated by measurement of the urinary excretion of naphthols, 2-methylphenol and dimethylphenol isomers by means of gas chromatography with a flame ionization detection (GC/FID). Urine metabolites were extracted after enzymatic hydrolysis by solid-phase extraction with styrene-divinylbenzene resin. The time-weighted average concentrations of the hydrocarbons detected in the breathing zone air shows that the exposure levels of the workers are relatively low in comparison to the exposure limits. Statistically significant differences between average concentrations of aromatic hydrocarbons (benzene, toluene, xylene isomers) determined at the workplaces in the tar distillation department have been found. Concentrations of the naphthalene and acenaphthene detected in workers from the oil distillation department are higher that those from the tar distillation department. Concentrations of naphthols, 2-methoxyphenol and dimethylphenol isomers in the urine of occupationally exposed workers were significantly higher than those of non-exposed subjects. Concentrations of the 2-methoxyphenol and dimethylphenol isomers in urine were significantly higher for the tar distillation workers, whereas concentrations of naphthols were higher for the oil naphthalene distillation workers. Operators at the tar and naphthalene oil distillation processes are simultaneously exposed to a mixture of different hydrocarbons

  15. Electron transport in single molecules: from benzene to graphene.

    Science.gov (United States)

    Chen, F; Tao, N J

    2009-03-17

    Electron movement within and between molecules--that is, electron transfer--is important in many chemical, electrochemical, and biological processes. Recent advances, particularly in scanning electrochemical microscopy (SECM), scanning-tunneling microscopy (STM), and atomic force microscopy (AFM), permit the study of electron movement within single molecules. In this Account, we describe electron transport at the single-molecule level. We begin by examining the distinction between electron transport (from semiconductor physics) and electron transfer (a more general term referring to electron movement between donor and acceptor). The relation between these phenomena allows us to apply our understanding of single-molecule electron transport between electrodes to a broad range of other electron transfer processes. Electron transport is most efficient when the electron transmission probability via a molecule reaches 100%; the corresponding conductance is then 2e(2)/h (e is the charge of the electron and h is the Planck constant). This ideal conduction has been observed in a single metal atom and a string of metal atoms connected between two electrodes. However, the conductance of a molecule connected to two electrodes is often orders of magnitude less than the ideal and strongly depends on both the intrinsic properties of the molecule and its local environment. Molecular length, means of coupling to the electrodes, the presence of conjugated double bonds, and the inclusion of possible redox centers (for example, ferrocene) within the molecular wire have a pronounced effect on the conductance. This complex behavior is responsible for diverse chemical and biological phenomena and is potentially useful for device applications. Polycyclic aromatic hydrocarbons (PAHs) afford unique insight into electron transport in single molecules. The simplest one, benzene, has a conductance much less than 2e(2)/h due to its large LUMO-HOMO gap. At the other end of the spectrum, graphene

  16. 低剂量辐射复合CO、苯和噪声对大鼠的生物效应研究%The combined biological effects of low dose radiation, carbon monoxide, benzene and noise on rats

    Institute of Scientific and Technical Information of China (English)

    陈伟; 何颖; 侯登勇; 钱甜甜; 莫琳芳; 蒋定文; 王庆蓉; 沈先荣

    2012-01-01

    目的 探讨低剂量辐射复合CO、苯和噪声等复合因素对大鼠生物效应的影响.方法 16只雄性SD大鼠随机分成实验组及对照组.实验组采用CO和苯染毒,并进行低剂量辐射和噪声暴露,对照组正常环境饲养.计数大鼠外周血细胞,检测各脏器指数、骨髓DNA含量,利用双向凝胶电泳和基质辅助激光解析飞行时间串联质谱技术分离、鉴定复合因素导致的大鼠血清差异表达蛋白.结果 与对照组相比,实验组大鼠的肝指数、脾指数、胸腺指数显著降低(t=2.732、4.141、3.053,P<0.05),外周血白细胞、血小板和骨髓DNA含量均显著降低(t=2.211、2.668、11.592,P<0.05).获得了血清蛋白凝胶电泳图谱,软件分析结合手工筛选出12个差异表达蛋白质点,鉴定血浆淀粉样蛋白A4(SAA4),Trichoplein角质细丝结合蛋白(TCHP)和α微管蛋白4A(TUBA4A)3个蛋白质点.结论 低剂量辐射复合CO、苯和噪声对大鼠造血系统、免疫系统损伤明显,导致大鼠血清中某些蛋白表达发生变化,发现差异表达的蛋白与复合因素损伤作用密切相关.%Objective To investigate the combined biological effects of low dose radiation,carbon monoxide,benzene and noise on rats.Methods Sixteen male SD rats were randomly divided into experiment group and control group.The experiment group was exposed to carbon monoxide,benzene,low dose radiation and noise daily,the control group was in common environment.Peripheral blood,organ index,and marrow DNA content were detected.Two-dimensional electrophoresis (2-DE) was performed on serum protein analysis.Differential expressed proteins were identified by a matrix assisted laser desorption/ionization time of flight mass spectrometry (MAIDI-TOF-MS).Results Compared to control group,the liver index,spleen index,thymus index,leukocytes,platelets count,and marrow DNA content of the experiment group were decreased significantly (t =2.732,4.141,3.053,2.211,2.668,11.592,P

  17. Evaluation of chromosome painting to assess the induction and persistence of chromosome aberrations in bone marrow cells of mice treated with benzene

    Energy Technology Data Exchange (ETDEWEB)

    Stronati, Laura; Farris, Alessandra; Pacchierotti, Francesca

    2004-01-12

    Fluorescence in situ hybridization with chromosome-specific painting probes (FISH painting) has been successfully applied to detect radiation-induced stable aberrations in humans and mice, whereas a few mouse studies with chemicals mostly failed to show any increase in chromosome-painting-detectable changes, especially in bone marrow cells. To further explore the feasibility of the painting approach to detect chemically induced stable aberrations, we treated mice with a single high dose of benzene, a potent bone-marrow-targeting clastogenic chemical and sacrificed them 24, 36 h or 15 days later to collect bone marrow cells and analyze chromatid- and chromosome-type aberrations by FISH painting. In addition, we treated another group of mice with 18 daily low doses to show the potential for aberration induction and accumulation under chronic exposure. Chromatid-type aberrations were significantly increased 24 and 36 h after acute treatment while chromosome-type ones were elevated above control values 36 h and 15 days after exposure, showing that at least part of benzene-induced chromatid exchanges were converted into potentially stable chromosome aberrations. The most common aberration was an extra copy of one painted chromosome in a metaphase with the euploid number of centromeres which was interpreted as the consequence of a symmetric recombination between pericentromeric regions of one painted and one unpainted chromatid. Under chronic exposure, neither chromosome- nor chromatid-type aberrations were significantly elevated over control values, suggesting that the probability of enough primary lesions and secondary DNA double strand breaks occurring close enough together in time to allow chromosome exchanges to form is a critical limiting factor especially in a cycling cell population.

  18. Electrochemical radiofluorination. Labeling of benzene with [18F]fluoride by nucleophilic substitution

    International Nuclear Information System (INIS)

    18F-labeling of aromatic compounds normally is achieved by electrophilic substitution. In that case [18F]fluoride cannot be applied although it is produced very efficiently at medical cyclotrons. By the use of electrochemical methods, however, benzene can be oxidized and thus, the electron density is reduced in a way that nucleophilic attack of [18F]fluoride occurs. For the first time benzene was shown to be labeled with [18F]fluoride after being electrochemically oxidized in a 2 ml electrolysis cell with 0.033M Et3N x 3HF and 0.066M Et3N x HCl in CH3CN and benzene in various concentrations. After 50 Coulombs (60-90 min) maximum of labeling was reached. With the highest concentration of aromatic compound (1.0M) the radiochemical yields were 16±9% with specific activities up to 27 GBq/mmol. (author)

  19. Feynman path integral - ab initio investigation of the excited-state properties of benzene

    International Nuclear Information System (INIS)

    The Feynman path integral Monte Carlo formalism has been combined with an ab initio configuration interaction scheme to study the excited singlet states of benzene under consideration of the nuclear degrees of freedom. Transition energies and oscillator strengths, which have been evaluated as ensemble averages over large sets of nuclear configurations, are correlated with single-configuration results derived for the D6h minimum of benzene. The quantum fluctuations of the benzene nuclei cause a strong redistribution of transition intensities. Transitions which are dipole allowed in the rigid D6h geometry of C6H6 lose intensity due to vibronic coupling; vice versa for transitions which are dipole forbidden in the D6h case. (author)

  20. Genetic effects of benzene and radiation in ICR and X/Gf mice

    International Nuclear Information System (INIS)

    X/Gf mice (a tumor-resistant strain) were compared with ICR mice (moderately tumor-sensitive) for their sensitivity to chromosomal damage caused by benzene, cyclophosphamide (CP), benzo(a)pyrene (BP) and radiation. There was no difference between strains in the level of micronucleus formation caused by BP, CP or radiation. Although X/Gf mice metabolized somewhat less of the dose of benzene per weight than ICR mice, and had somewhat higher levels of genetic damage, it is not known whether X/Gf mice would be measurably more resistant to benzene carcinogenicity. Short-term genotoxicity tests are used as indicators of initiation, therefore, equal sensitivity to a set of standard clastogens suggests that tumor resistance in X/Gf mice is a function of later stages of carcinogenesis. (author)

  1. Reactions of 1,4-bis(tetrazole)benzenes: formation of long chain alkyl halides

    OpenAIRE

    Kelleher, Fintan; Bond, Andrew; Fleming, Adrienne; McGinley, John; Prajapati, Vipa

    2006-01-01

    The reactions of 1,4-bis[2-(tributylstannyl)tetrazol-5-yl]benzene with α,ω-dibromoalkanes were carried out in order to synthesise pendant alkyl halide derivatives of the parent bis-tetrazole. This led to the formation of several alkyl halide derivatives, substituted variously at N1 or N2 on the tetrazole ring. The crystal structures of 1,4-bis[(2-(4-bromobutyl)tetrazol-5-yl)]benzene (2-N,2-N′), 1,4-bis[(2-(4-bromobutyl)tetrazol-5-yl)]benzene (1-N,2-N′) and 1,4-bis[(2-(8-bromooctyl)tetra...

  2. OH-initiated oxidation of benzene - Part II. Influence of elevated NOx concentrations

    DEFF Research Database (Denmark)

    Klotz, B; Volkamer, R; Hurley, MD;

    2002-01-01

    The present work represents a continuation of part I of this series of papers, in which we investigated the phenol yields in the OH-initiated oxidation of benzene under conditions of low to moderate concentrations of NOx, to elevated NOx levels. The products of the OH-initiated oxidation of benzene...... in 700 760 Torr of N-2/O-2 diluent at 297 +/- 4 K were investigated in 3 different photochemical reaction chambers. In situ spectroscopic techniques were employed for the detection of products, and the initial concentrations of benzene, NOx, and O-2 were widely varied (by factors of 6300, 1500, and...... 13, respectively). In contrast to results from previous studies, a pronounced dependence of the product distribution on the NOx concentration was observed. The phenol yield decreases from approximately 50-60% in the presence of low concentrations (10 000 ppb) NOx concentrations. In the presence of...

  3. Measurement of Benzene in Air by Iranian Single-Wall Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Athena Rafieepour

    2012-01-01

    Full Text Available Background: Nanotechnology is a new approach that has been lionized in recentyears. One of its applications is its consumption as an absorbent. In this study, thesingle-wall carbon nanotubes (SWCNTs were used as an absorbent for samplingbenzene in the air.Materials and Methods: For this study, SWCNTs manufactured by Iran and SKC’sactivated charcoal were used for sampling benzene vapors. Preparation and analysis ofthe samples were done by carbon disulfide and GC-FID (gas chromatography-flameionization detector, respectivelyResults: The results indicated that the performance of SWCNTs is less thanconventional activated charcoal for sampling benzene vapors in the airConclusion: The findings of this study showed that the performance of SWCNTs inthe sampling of benzene vapors in the air is very poor and, therefore, cannot be a goodalternative to SKC’s activated charcoal.

  4. Poly[tetraaqua(μ4-benzene-1,3,5-tricarboxylatosodium(Izinc(II

    Directory of Open Access Journals (Sweden)

    Chao-Hong Ma

    2010-04-01

    Full Text Available In the title compound, [NaZn(C9H3O6(H2O4]n, the ZnII atom is six-coordinated by four O atoms from two different benzene-1,3,5-tricarboxylate anions and two water O atoms in a distorted tetragonal-bipyramidal geometry and the NaI atom is five-coordinated by three O atoms from three different benzene-1,3,5-tricarboxylate anions and two water O atoms in a distorted trigonal-bipyramidal geometry. The benzene-1,3,5-tricarboxylate anion bridges two ZnII atoms and two NaI atoms, resulting in the formation of a two-dimensional layer structure. Intermolecular O—H...O hydrogen-bonding interactions generate a three-dimensional superamolecular structure.

  5. Risk estimation of benzene-induced leukemia by radiation equivalent dose

    International Nuclear Information System (INIS)

    Based on the Hiroshima and Nagasaki epidemiological study, risk assessment system for radiation has been well developed and is practically applied to the international protection standards. Hence, defining the radiation equivalent dose for chemical agents could place in the order of their risk. As well as the radiation, benzene causes leukemia to humans. Therefore, we evaluated the radiation-equivalent dose for benzene based on chromosome aberration rates induced by its metabolites and low-dose rate radiation because chromosome aberration is thought to be closely related to the leukemogenesis. Using radiation risk coefficient, the leukemia risk caused by 1 mg/m3 benzene inhalation was estimated 5.5 - 7.3 x 10-8, which is underestimated compared to other studies based on human epidemiological researches. (author)

  6. Characterization of vanadium-doped mesoporous titania and its adsorption of gaseous benzene

    Science.gov (United States)

    Nguyen-Phan, Thuy-Duong; Song, Myoung Bock; Yun, Hyunran; Kim, Eui Jung; Oh, Eun-Suok; Shin, Eun Woo

    2011-01-01

    A series of vanadium-doped mesoporous titania with different metal contents was synthesized in the study via a sol-gel process with the assistance of a dodecylamine surfactant. The existence of vanadium ions not only suppressed crystallization and sintering but also enhanced the porosity of the mesoporous TiO 2. Varying the vanadium concentration led to significant changes in the chemical oxidation state of each component. The presence of metal dopants significantly improved the removal efficiency of benzene and the doping the titania with 5 mol% vanadium removed the most benzene, regardless of the adsorption temperature. The adsorption behavior was elucidated by the specific surface area, the interactions between surface hydroxyl groups and the π-electrons of benzene, and the formation of σ-bonding and d-π* back-donation between the adsorbent and organic compounds.

  7. Catalytic Synthesis of Isopropyl Benzene over SO42-/ZrO2 -MCM-41

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Super acid catalyst SO2-4-/ZrO2 was introduced into pure silicone MCM-41 via the impregnation method and the catalyst samples obtained at different temperatures were characterized by means of XRD, IR, and Py-IR techniques.The selectively catalytic gas-phase flow reactions of benzene with propene over the catalyst samples were carried out in a made-to-measure high-pressure flow reactor equipped with a thermostat and a condenser. Effect of the preparative condition on the catalytic synthesis of isopropyl benzene over the catalyst samples was tested. The results show that SO2-4/ZrO2-MCM-41 (SZM-41) can be used as a catalyst for the title reaction, in which there are a higher conversion (97%) for the propene and a higher selectivity(93%) for the isopropyl benzene.

  8. PERVAPORATION FOR SEPARATING BENZENE/CYCLOHEXANE MIXTURE BY P(AA-MA) COPOLYMER MEMBRANES

    Institute of Scientific and Technical Information of China (English)

    Gao-fei Xu; Wei-pu Zhu

    2011-01-01

    P(AA-MA) copolymers composed of acrylic acid and methyl acrylate with different molecular weights and sequence structures were synthesized by combination of ATRP and selective hydrolysis. These copolymers were used as membrane materials to separate benzene/cyclohexane mixture by pervaporation. The effects of molecular weight and sequence structure of the copolymers on the pervaporation performance were investigated in detail. For the random copolymers, the permeate flux decreased rapidly with the increasing of molecular weight. The separation factor was also influenced by the molecular weight, which was changed from no selectivity to cyclohexane selectivity with increasing the molecular weight. Contrarily, the block copolymer membrane showed good benzene selectivity with separation factor of 4.3 and permeate flux of 157 g/(m2h) to 50 wt% benzene/cyclohexane mixture.

  9. The Role of Acid Strength of Modified NaX Zeoliteson Gas Phase Ethylation of Benzene

    Directory of Open Access Journals (Sweden)

    Sanghamitra Barman

    2010-01-01

    Full Text Available The role of acid strength of modified NaX zeolites in gas phase ethylation of benzene were studied over Ce exchanged NaX zeolite of different types. Acidity of the modified zeolite was investigated by means of adsorbing ammonia at different temperature. The conversion of reactantsvaries with the acid strength as well as the different types of the zeolites. The strong acid sites are active centers while the weak acid sites are inactive. The influences of various process parameters such as temperature, space-time and the feed ratio of benzene to ethanol on benzene conversion over most acidic zeolite were studied. The kinetic and adsorption constants of the rate equations were estimated by the best fit. From the estimated kinetic constants, the activation energies and frequency factors for various reactions were determined. The activation energy values compared well with those reported by other investigators for same reactions over similar catalysts.

  10. Protective role of glycerol against benzene stress: insights from the Pseudomonas putida proteome.

    Science.gov (United States)

    Bhaganna, Prashanth; Bielecka, Agata; Molinari, Gabriella; Hallsworth, John E

    2016-05-01

    Chemical activities of hydrophobic substances can determine the windows of environmental conditions over which microbial systems function and the metabolic inhibition of microorganisms by benzene and other hydrophobes can, paradoxically, be reduced by compounds that protect against cellular water stress (Bhaganna et al. in Microb Biotechnol 3:701-716, 2010; Cray et al. in Curr Opin Biotechnol 33:228-259, 2015a). We hypothesized that this protective effect operates at the macromolecule structure-function level and is facilitated, in part at least, by genome-mediated adaptations. Based on proteome profiling of the soil bacterium Pseudomonas putida, we present evidence that (1) benzene induces a chaotrope-stress response, whereas (2) cells cultured in media supplemented with benzene plus glycerol were protected against chaotrope stress. Chaotrope-stress response proteins, such as those involved in lipid and compatible-solute metabolism and removal of reactive oxygen species, were increased by up to 15-fold in benzene-stressed cells relative to those of control cultures (no benzene added). By contrast, cells grown in the presence of benzene + glycerol, even though the latter grew more slowly, exhibited only a weak chaotrope-stress response. These findings provide evidence to support the hypothesis that hydrophobic substances induce a chaotropicity-mediated water stress, that cells respond via genome-mediated adaptations, and that glycerol protects the cell's macromolecular systems. We discuss the possibility of using compatible solutes to mitigate hydrocarbon-induced stresses in lignocellulosic biofuel fermentations and for industrial and environmental applications. PMID:26612269

  11. Qualitative evaluations of benzene in terminals and pipelines; Avaliacoes qualitativas de benzeno em terminais e oleodutos

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Edson Ferreira da; Baltar, Joao Luiz da Conceicao [TRANSPETRO - PETROBRAS Transportes, Rio de Janeiro, RJ (Brazil)

    2005-07-01

    The benzene (C6H6) is a stable hydrocarbon, with pleasant smell, plenty toxic, being able to injure sanguine cells and to cause cancer. It is used as raw materials in the obtainment of several products (inks, waxes, lubricants, etc.), chemicals intermediate and, also, it is found in the petrochemical naphtha and in the gasoline. About 80% of the contaminations for benzene are attributed to the gasoline. In relation to the benzene contents present in the petrochemical processes produced in Brazil, the recent Portaria Interministerial no. 775 (Brazil,2004), of April 28, 2004, prohibits, in whole national territory, the commercialization of finished products that contain benzene in its composition. It is admitted, even so, the presence of this substance as contaminant agent in percentage non superior at 0,8% (in volume), from July 1st, 2004, 0,4% (in volume), from 1st of December of 2005 and 0,1% (in volume), from December 1st, 2007. The Brazilian Ministry of Labour regulation NR-15, P. 776, establish that the companies that produce, transport, store, use or manipulate benzene and its liquid mixtures contends 1% or more of volume, accomplish the registration in the SST - MTE and initiation the Programa de Prevencao de Exposicao Ocupacional ao Benzeno - PPEOB in TRANSPETRO. During the evaluations they had been carried through the recognition of the places, equipment and they had defined the homogeneous groups of exhibition - GHE. From these information, environmental and biological evaluations in the terminals and intermediary stations (TECAM, TEVOL, ESTAP, ESMAN, ESVOL and ESJAP), had been executed, including the accomplishment of essays to determine the presence of benzene in the liquid phase, through the infrared base equipment, GS 1000. With base in the results mitigation and remediation actions were implemented in order to guarantee the occupational health of the components of GHE. (author)

  12. Anaerobic biodegradation of benzene series compounds by mixed cultures based on optional electronic acceptors

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A series of batch experiments were performed using mixed bacterial consortia to investigate biodegradation performance of benzene,toluene,ethylbenzene and three xylene isomers (BTEX) under nitrate,sulfate and ferric iron reducing conditions.The results showed that toluene,ethylbenzeoe,m-xylene and o-xylene could be degraded independently by the mixed cultures coupled to nitrate,sulfate and ferric iron reduction.Under ferric iron reducing conditions the biodegradation of benzene and p-xylene could be occurred only in the presence of other alkylbenzenes.Alkylbenzenes can serve as the primary substrates to stimulate the transformation of benzene and p-xylene under anaerobic conditions.Benzene and p-xylene are more toxic than toluene and ethylbenzene,under the three terminal electron acceptors conditions,the degradation rates decreased with toluene > ethylbenzene > m-xylene > o-xylene > benzene > p-xylene.Nitrate was a more favorable electron acceptor compared to sulfate and ferric iron.The ratio between sulfate consumed and the loss of benzene,toluene,ethylbenzene,o-xylene,m-xylene,p-xylene was 4.44,4.51,4.42,4.32,4.37 and 4.23,respectively;the ratio between nitrate consumed and the loss of these substrates was 7.53,6.24,6.49,7.28,7.81,7.61,respectively;the ratio between the consumption of ferric iron and the loss of toluene,ethylbenzene,o-xylene,m-xylenewas 17.99,18.04,18.07,17.97,respectively.

  13. Assessing the air quality impact of nitrogen oxides and benzene from road traffic and domestic heating and the associated cancer risk in an urban area of Verona (Italy)

    Science.gov (United States)

    Schiavon, Marco; Redivo, Martina; Antonacci, Gianluca; Rada, Elena Cristina; Ragazzi, Marco; Zardi, Dino; Giovannini, Lorenzo

    2015-11-01

    Simulations of emission and dispersion of nitrogen oxides (NOx) are performed in an urban area of Verona (Italy), characterized by street canyons and typical sources of urban pollutants. Two dominant source categories are considered: road traffic and, as an element of novelty, domestic heaters. Also, to assess the impact of urban air pollution on human health and, in particular, the cancer risk, simulations of emission and dispersion of benzene are carried out. Emissions from road traffic are estimated by the COPERT 4 algorithm, whilst NOx emission factors from domestic heaters are retrieved by means of criteria provided in the technical literature. Then maps of the annual mean concentrations of NOx and benzene are calculated using the AUSTAL2000 dispersion model, considering both scenarios representing the current situation, and scenarios simulating the introduction of environmental strategies for air pollution mitigation. The simulations highlight potentially critical situations of human exposure that may not be detected by the conventional network of air quality monitoring stations. The proposed methodology provides a support for air quality policies, such as planning targeted measurement campaigns, re-locating monitoring stations and adopting measures in favour of better air quality in urban planning. In particular, the estimation of the induced cancer risk is an important starting point to conduct zoning analyses and to detect the areas where population is more directly exposed to potential risks for health.

  14. Synergistic action of the benzene metabolite hydroquinone on myelopoietic stimulating activity of granulocyte/macrophage colony-stimulating factor in vitro

    Science.gov (United States)

    Irons, R. D.; Stillman, W. S.; Colagiovanni, D. B.; Henry, V. A.; Clarkson, T. W. (Principal Investigator)

    1992-01-01

    The effects of in vitro pretreatment with benzene metabolites on colony-forming response of murine bone marrow cells stimulated with recombinant granulocyte/macrophage colony-stimulating factor (rGM-CSF) were examined. Pretreatment with hydroquinone (HQ) at concentrations ranging from picomolar to micromolar for 30 min resulted in a 1.5- to 4.6-fold enhancement in colonies formed in response to rGM-CSF that was due to an increase in granulocyte/macrophage colonies. The synergism equaled or exceeded that reported for the effects of interleukin 1, interleukin 3, or interleukin 6 with GM-CSF. Optimal enhancement was obtained with 1 microM HQ and was largely independent of the concentration of rGM-CSF. Pretreatment with other authentic benzene metabolites, phenol and catechol, and the putative metabolite trans, trans-muconaldehyde did not enhance growth factor response. Coadministration of phenol and HQ did not enhance the maximal rGM-CSF response obtained with HQ alone but shifted the optimal concentration to 100 pM. Synergism between HQ and rGM-CSF was observed with nonadherent bone marrow cells and lineage-depleted bone marrow cells, suggesting an intrinsic effect on recruitment of myeloid progenitor cells not normally responsive to rGM-CSF. Alterations in differentiation in a myeloid progenitor cell population may be of relevance in the pathogenesis of acute myelogenous leukemia secondary to drug or chemical exposure.

  15. Penning ionization : In benzene · Ar and fluorobenzene · Ar van der waals molecules and in collisions of benzene with metastable Ar atoms

    Science.gov (United States)

    Rühl, E.; Bisling, P.; Brutschy, B.; Beckmann, K.; Leisen, O.; Morgner, H.

    1986-08-01

    The photoion efficiency curves of the van der Waals complexes benzene ·Ar (Bz·Ar) and fluorobenzene·Ar (Fb·Ar) exhibit sharp resonances, which correspond to excitation to the Ar 2P 3/24s and 2P 1/24s resonance states. The peaks are redshifted relative to their asymptotic values (Bz·Ar, Δ E = -70 ± 10 meV; Fb·Ar, Δ E = -40 ± 10 meV). These findings are supported by electron spectroscopy studies of the Penning ionization of benzene by state-selected metastable Ar ( 3p 2, 3p 0) atoms. Strong evidence is presented that Penning ionization is the process observed in both cases.

  16. Effect of the Number of Benzene-Ring, the Functional Groups and the Absorbent Material on the Performance of Pt Nanoparticles Supported on Modified Graphite Nanoplatelet

    International Nuclear Information System (INIS)

    A graphite nanoplatelet (GNP) modified with small organic molecules and inorganic element was prepared and subsequently used as an electrocatalyst for the electrooxidation of methanol. The Pt/modified-GNP composite catalyst was characterized by Raman spectrometer, X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy. The electrochemical properties and electrocatalytic activities of the Pt/modified-GNP hybrid were evaluated by cyclic voltammetry and chronoamperometry. The results indicate that the number of benzene-ring in the organic molecules and the identity of the inorganic elements can influence the dispersion of the Pt nanoparticles. Combine the inorganic elements with aminopyrene (amin) improved the activity of the resultant catalysts for methanol electrooxidation. The activity of the catalysts exhibits an order of Pt/Sn-amin-G < Pt/Ce-amin-G < Pt/Al-amin-G

  17. Experimental density, viscosity, interfacial tension and water solubility of ethyl benzene-α-methyl benzyl alcohol–water system

    International Nuclear Information System (INIS)

    Highlights: • Properties were measured for MBA (methyl benzyl alcohol)-EB (ethyl benzene)-water. • MBA concentration was found to influence all the properties strongly. • The water solubility, density, and viscosity increased at high MBA concentration. • The interfacial tension decreased sharply at high MBA concentration. • MBA dictates the phase separation and mass transfer of the ternary system. -- Abstract: Density, viscosity, interfacial tension, and water solubility were measured for the (α-methyl benzyl alcohol (MBA) + Ethyl benzene (EB)) system at different concentrations of MBA in contact with water and sodium hydroxide solution (0.01 mol · kg−1) as aqueous phases. The properties were measured to identify the component which plays a governing role in changing the physical properties relevant to mass transfer and phase separation of the ternary system. The concentration of MBA was found to be the major factor influencing all the properties. The water solubility, the density, and the viscosity increased notably at higher concentrations of MBA; while, the interfacial tension decreased strongly. The use of 0.01 mol · kg−1 NaOH as an aqueous phase resulted in a decrease of the interfacial tension and a minor decrease in the water solubility. The density data were correlated using a quadratic mixing rule to describe the influence of concentration at any temperature. The viscosity data are correlated using the Nissan and Grunberg and Katti-Chaudhri equations. The Szyzkowski’s equation was used to correlate the interfacial tension data. The water solubility data were described using an exponential relationship. All the correlations described the experimental physical property data adequately

  18. State-resolved three-dimensional electron-momentum correlation in nonsequential double ionization of benzene

    Science.gov (United States)

    Winney, Alexander H.; Lin, Yun Fei; Lee, Suk Kyoung; Adhikari, Pradip; Li, Wen

    2016-03-01

    We report state-resolved electron-momentum correlation measurement of strong-field nonsequential double ionization in benzene. With a novel coincidence detection apparatus, highly efficient triple coincidence (electron-electron dication) and quadruple coincidence (electron-electron-cation-cation) are used to resolve the final ionic states and to characterize three-dimensional (3D) electron-momentum correlation. The primary states associated with dissociative and nondissociative dications are assigned. A 3D momentum anticorrelation is observed for the electrons in coincidence with dissociative benzene dication states whereas such a correlation is absent for nondissociative dication states.

  19. Bond Energy Sums in Benzene, Cyclohexatriene and Cyclohexane Prove Resonance Unnecessary

    OpenAIRE

    Heyrovska, Raji

    2008-01-01

    The recent new structure of benzene shows that it consists of three C atoms of radii as in graphite alternating with three C atoms with double bond radii. This is different from the hypothetical cyclohexatriene (Kekule structure) involving alternate double and single bonds. It was shown that the difference in the bond energy sum of the atomic structure of benzene from that of the Kekule structure is the energy (erroneously) assumed to be due to resonance. Here it is shown that the present str...

  20. An epidemiologic study of early biologic effects of benzene in Chinese workers

    Energy Technology Data Exchange (ETDEWEB)

    Rothman, N.; Hayes, R.B.; Dosemeci, M. [National Cancer Institute, Bethesda, MD (United States)] [and others

    1996-12-01

    Benzene is a recognized hepatotoxin and leukemogen, but its mechanisms of action in humans are still uncertain. To provide insight into these processes, we carried out a cross-sectional study of 44 healthy workers currently exposed to benzene (median 8-hr time-weighted average; 31 ppm), and unexposed controls in Shanghai, China. Here we provide an overview of the study results on peripheral blood cell levels and somatic cell mutation frequency measured by the glycophorin A (GPA) gene loss assay and report on peripheral cytokine levels. 41 refs., 5 tabs.