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Sample records for airborne benzene levels

  1. Airborne benzene exposures from cleaning metal surfaces with small volumes of petroleum solvents.

    PubMed

    Hollins, Dana M; Kerger, Brent D; Unice, Kenneth M; Knutsen, Jeffrey S; Madl, Amy K; Sahmel, Jennifer E; Paustenbach, Dennis J

    2013-06-01

    Airborne benzene concentrations were measured in a room with controlled air exchange during surface cleaning with two petroleum-based solvents (a paint thinner and an engine degreaser). The solvents were spiked with benzene to obtain target concentrations of 0.001, 0.01, and 0.1% by volume in the liquid. Personal samples on the worker and area samples up to 1.8m away were collected over 12 events (n=84 samples) designed to examine variation in exposure with solvent type, cleaning method (rag wipe or spatula scrape), surface area cleaned, air exchange rate, solvent volume applied, and distance from the cleaned surface. Average task breathing zone concentrations of benzene represented by 18-32 min time-weighted averages were 0.01 ppm, 0.05 ppm, and 0.27 ppm, when the solvents contained approximately 0.003, 0.008, and 0.07% benzene. Solvent benzene concentration, volume applied, and distance from the handling activities had the greatest effect on airborne concentrations. The studied solvent products containing 0.07% benzene (spiked) did not exceed the current OSHA permissible exposure limit of 1 ppm (averaged over 8h) or the ACGIH Threshold Limit Value of 0.5 ppm, in any of the tested short-term exposure scenarios. These data suggest that, under these solvent use scenarios, petroleum-based solvent products produced in the United States after 1978 likely did not produce airborne benzene concentrations above those measured if the concentration was less than 0.1% benzene. PMID:23088855

  2. Airborne benzene exposures from cleaning metal surfaces with small volumes of petroleum solvents.

    PubMed

    Hollins, Dana M; Kerger, Brent D; Unice, Kenneth M; Knutsen, Jeffrey S; Madl, Amy K; Sahmel, Jennifer E; Paustenbach, Dennis J

    2013-06-01

    Airborne benzene concentrations were measured in a room with controlled air exchange during surface cleaning with two petroleum-based solvents (a paint thinner and an engine degreaser). The solvents were spiked with benzene to obtain target concentrations of 0.001, 0.01, and 0.1% by volume in the liquid. Personal samples on the worker and area samples up to 1.8m away were collected over 12 events (n=84 samples) designed to examine variation in exposure with solvent type, cleaning method (rag wipe or spatula scrape), surface area cleaned, air exchange rate, solvent volume applied, and distance from the cleaned surface. Average task breathing zone concentrations of benzene represented by 18-32 min time-weighted averages were 0.01 ppm, 0.05 ppm, and 0.27 ppm, when the solvents contained approximately 0.003, 0.008, and 0.07% benzene. Solvent benzene concentration, volume applied, and distance from the handling activities had the greatest effect on airborne concentrations. The studied solvent products containing 0.07% benzene (spiked) did not exceed the current OSHA permissible exposure limit of 1 ppm (averaged over 8h) or the ACGIH Threshold Limit Value of 0.5 ppm, in any of the tested short-term exposure scenarios. These data suggest that, under these solvent use scenarios, petroleum-based solvent products produced in the United States after 1978 likely did not produce airborne benzene concentrations above those measured if the concentration was less than 0.1% benzene.

  3. Correlations among atmospheric elements, airborne particulate matter, benzene extracts, benzo(a)pyrene, NO, NO 2 and so 2 concentrations in Japan

    NASA Astrophysics Data System (ADS)

    Fukino, H.; Mimura, S.; Inoue, K.; Yamane, Y.

    Concentration levels of elements, airborne particulate matter, benzene extracts, benzo(a)pyrene B(a)P, NO, NO 2 and SO 2 in five residential areas were seasonally determined from May 1979 to January 1980. These air pollutants exhibited higher concentration in autumn and winter than in spring and summer. These were correlations among Pb, Cu, Ni, V and Se, among Si, Fe, Al and Ti and among NO, NO 2, B(a)P, benzene extracts and airborne particulate matter. NO, NO 2, B(a)P, benzene extracts and airborne particulate matter were correlated with Pb, Cu, Ni, V and Se, but not appreciably with Si, Fe, Al and Ti. On the basis of correlations between various air pollutants, the emitting source of the air pollutants and the health hazard by combined air pollution were discussed.

  4. Airborne concentrations of benzene due to diesel locomotive exhaust in a roundhouse.

    PubMed

    Madl, Amy K; Paustenbach, Dennis J

    2002-12-13

    Concentrations of airborne benzene due to diesel exhaust from a locomotive were measured during a worst-case exposure scenario in a roundhouse. To understand the upper bound human health risk due to benzene, an electromotive diesel and a General Electric four-cycle turbo locomotive were allowed to run for four 30-min intervals during an 8-h workshift in a roundhouse. Full-shift and 1-h airborne concentrations of benzene were measured in the breathing zone of surrogate locomotive repairmen over the 8-h workshift on 2 consecutive days. In addition, carbon monoxide was measured continuously; elemental carbon (surrogate for diesel exhaust) was sampled with full-shift area samples; and nitrogen dioxide/nitric oxide was sampled using full-shift and 15-min (nitrogen dioxide only) area samples. Peak concentrations of carbon monoxide ranged from 22.5 to 93 ppm. The average concentration of elemental carbon for each day of the roundhouse study was 0.0543 and 0.0552 microg/m(3 )for an 8-h workshift. These were considered "worst-case" conditions since the work environment was intolerably irritating to the eyes, nose, and throat. Short-term nitrogen dioxide concentrations ranged from 0.81 to 2.63 ppm during the diesel emission events with the doors closed. One-hour airborne benzene concentrations ranged from 0.001 to 0.015 ppm with 45% of the measurements below the detection limit of 0.002-0.004 ppm. Results indicated that the 8-h time-weighted average for benzene in the roundhouse was approximately 100-fold less than the current threshold limit value (TLV) of 0.5 ppm. These data are consistent with other studies, which have indicated that benzene concentrations due to diesel emissions, even in a confined environment, are quite low.

  5. An analysis of historical exposures of pressmen to airborne benzene (1938-2006).

    PubMed

    Novick, Rachel M; Keenan, James J; Gross, Sherilyn A; Paustenbach, Dennis J

    2013-07-01

    Benzene is an aromatic hydrocarbon that, with sufficient cumulative lifetime doses, can cause acute myelogenous leukemia. Because of its volatility and solvent properties, it was used in the printing industry in inks, ink solvents, and cleaning agents from the 1930s to the 1970s. This analysis represents the first known attempt to gather and synthesize the available data on historical airborne benzene concentrations in printing facilities and exposures to pressmen. The sources of fugitive benzene vapors from printing operations have been identified as evaporation from ink fountains, exposed sections of the printing cylinder, the paper web, the paper post exit, and spilled ink. In addition, specific activities that could lead to benzene exposure, such as filling the fountains, using solvents to clean the press, and using solvents as personal cleaning agents, potentially occurred multiple times per work period. Eighteen studies were identified that reported workplace airborne concentrations in printing facilities between 1938 and 2006. Typical benzene air concentrations, considering both personal and area samples of various durations, were as high as 200 p.p.m. in the 1930s through the 1950s, 3-35 p.p.m. in the 1960s, 1.3-16 p.p.m. in the 1970s, 0.013-1 in the 1980s, and far less than 1 p.p.m. in the 1990s and 2000s. The decrease in benzene air concentrations by the late 1970s was likely to be linked to the decreased benzene content of printing materials, increased engineering controls, and to more stringent occupational exposure limits.

  6. Airborne concentrations of benzene associated with the historical use of some formulations of liquid wrench.

    PubMed

    Williams, Pamela R D; Knutsen, Jeffrey S; Atkinson, Chris; Madl, Amy K; Paustenbach, Dennis J

    2007-08-01

    The current study characterizes potential inhalation exposures to benzene associated with the historical use of some formulations of Liquid Wrench under specific test conditions. This product is a multiuse penetrant and lubricant commonly used in a variety of consumer and industrial settings. The study entailed the remanufacturing of several product formulations to have similar physical and chemical properties to most nonaerosol Liquid Wrench formulations between 1960 and 1978. The airborne concentrations of benzene and other constituents during the simulated application of these products were measured under a range of conditions. Nearly 200 breathing zone and area bystander air samples were collected during 11 different product use scenarios. Depending on the tests performed, average airborne concentrations of benzene ranged from approximately 0.2-9.9 mg/m(3) (0.08-3.8 ppm) for the 15-min personal samples; 0.1-8 mg/m(3) (0.04-3 ppm) for the 1-hr personal samples; and 0.1-5.1 mg/m(3) (0.04-2 ppm) for the 1-hr area samples. The 1-hr personal samples encompassed two 15-min product applications and two 15-min periods of standing within 5 to 10 feet of the work area. The measured airborne concentrations of benzene varied significantly based on the benzene content of the formulation tested (1%, 3%, 14%, or 30% v/v benzene) and the indoor air exchange rate but did not vary much with the base formulation of the product or the two quantities of Liquid Wrench used. The airborne concentrations of five other volatile chemicals (ethylbenzene, toluene, total xylenes, cyclohexane, and hexane) were also measured, and the results were consistent with the volatility and concentrations of these chemicals in the product tested. A linear regression analysis of air concentration compared with the chemical mole fraction in the solution and air exchange rate provided a relatively good fit to the data. The results of this study should be useful for evaluating potential inhalation

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

    PubMed

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

    2014-01-01

    Benzene, a ubiquitous environmental pollutant, causes acute myeloid leukemia (AML). Recently, through transcriptome profiling of peripheral blood mononuclear cells (PBMC), we reported dose-dependent effects of benzene exposure on gene expression and biochemical pathways in 83 workers exposed across four airborne concentration ranges (from <1 ppm to >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.

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

    NASA Astrophysics Data System (ADS)

    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.

  9. Benzene

    Integrated Risk Information System (IRIS)

    EPA / 635 / R - 02 / 001F TOXICOLOGICAL REVIEW OF BENZENE ( NONCANCER EFFECTS ) ( CAS No . 71 - 43 - 2 ) In Support of Summary Information on the Integrated Risk Information System ( IRIS ) October 2002 U.S . Environmental Protection Agency Washington , DC DISCLAIMER This document has been reviewed

  10. Prolonged ethanol ingestion enhances benzene myelotoxicity and lowers urinary concentrations of benzene metabolite levels in CD-1 male mice.

    PubMed

    Marrubini, Giorgio; Castoldi, Anna F; Coccini, Teresa; Manzo, Luigi

    2003-09-01

    Benzene toxicity is attributed to its metabolism, which is primarily mediated by the ethanol-inducible cytochrome P450 2E1 isoform (CYP2E1). The present study investigated the myelotoxicity and urinary concentrations of major benzene metabolites in adult CD-1 male mice treated with low levels of benzene vapors, ethanol, or a combination of the two. Groups of ethanol-treated (5% in a Lieber-DeCarli liquid diet, 3 weeks) or pair-fed control mice were exposed to 10 ppm benzene, 6 h per day, 5 days per week for 2 weeks, starting from the second week of ethanol administration. On the last day of treatment, the number of early and late erythroid progenitors (BFU-E and CFU-E) was reduced by 55%, while the number of granulocyte/macrophage progenitors (CFU-GM) was reduced by 36% in benzene-treated mice. Ethanol lowered the CFU-E, BFU-E, and CFU-GM colony formation by 33, 28, and 12%, respectively. In animals coexposed to benzene and ethanol, the CFU-E colony counts were decreased by 70%, the BFU-E by 80%, and the CFU-GM by 45%. Phenol (Ph), hydroquinone (HQ), catechol (Cat), and trans,trans-muconic acid (MA) were measured by HPLC-UV in urine samples collected weekly during the last 6-h benzene/air exposure session. In benzene-exposed mice urinary metabolite levels peaked at the end of the first week of treatment (microg/kg body weight (bw): Ph: 4931 +/- 1055; Cat: 109 +/- 17; HQ: 784 +/- 137; MA: 534 +/- 92) and significantly decreased at the end of the second week (microg/kg bw: Ph: 3909 +/- 984; Cat: 82 +/- 24; HQ: 337 +/- 72; MA: 235 +/- 55). In mice given benzene and ethanol, the urinary levels of Ph, Cat, HQ, and MA were significantly lower than those measured in the group given benzene alone. The urinary levels of Ph and Cat showed a decreasing trend, again, from the first to the second week of benzene exposure. These data indicate that chronic ethanol ingestion exacerbates benzene myelotoxicity and, in addition, reduces the urinary excretion of benzene metabolites in

  11. Occupational exposures associated with petroleum-derived products containing trace levels of benzene.

    PubMed

    Williams, Pamela R D; Panko, Julie M; Unice, Ken; Brown, Jay L; Paustenbach, Dennis J

    2008-09-01

    Benzene may be present as a trace impurity or residual component of mixed petroleum products due to refining processes. In this article, the authors review the historical benzene content of various petroleum-derived products and characterize the airborne concentrations of benzene associated with the typical handling or use of these products in the United States, based on indoor exposure modeling and industrial hygiene air monitoring data collected since the late 1970s. Analysis showed that products that normally contained less than 0.1% v/v benzene, such as paints and paint solvents, printing solvents and inks, cutting and honing oils, adhesives, mineral spirits and degreasers, and jet fuel typically have yielded time-weighted average (TWA) airborne concentrations of benzene in the breathing zone and surrounding air ranging on average from <0.01 to 0.3 ppm. Except for a limited number of studies where the benzene content of the product was not confirmed to be <0.1% v/v, airborne benzene concentrations were also less than current occupational exposure limits (e.g., threshold limit value of 0.5 ppm and permissible exposure limit of 1.0 ppm) based on exceedance fraction calculations. Exposure modeling using Monte Carlo techniques also predicted 8-hr TWA near field airborne benzene concentrations ranging from 0.002 to 0.4 ppm under three hypothetical solvent use scenarios involving mineral spirits. The overall weight-of-evidence indicates that the vast majority of products manufactured in the United States after about 1978 contained <0.1% v/v benzene, and 8-hr TWA airborne concentrations of benzene in the workplace during the use of these products would not have been expected to exceed 0.5 ppm under most product use scenarios. [Supplementary materials are available for this article. Go to the publisher's online edition of Journal of Occupational and Environmental Hygiene for the following free supplemental resource: a document containing exposure modeling scenarios and

  12. Estimating Benzene Exposure Level over Time and by Industry Type through a Review of Literature on Korea

    PubMed Central

    Park, Donguk; Choi, Sangjun; Ha, Kwonchul; Jung, Hyejung; Yoon, Chungsik; Koh, Dong-Hee; Ryu, Seunghun; Kim, Soogeun; Kang, Dongmug; Yoo, Kyemook

    2015-01-01

    The major purpose of this study is to construct a retrospective exposure assessment for benzene through a review of literature on Korea. Airborne benzene measurements reported in 34 articles were reviewed. A total of 15,729 individual measurements were compiled. Weighted arithmetic means [AM(w)] and their variance calculated across studies were summarized according to 5-year period intervals (prior to the 1970s through the 2010s) and industry type. Industries were classified according to Korea Standard Industrial Classification (KSIC) using information provided in the literature. We estimated quantitative retrospective exposure to benzene for each cell in the matrix through a combination of time and KSIC. Analysis of the AM(w) indicated reductions in exposure levels over time, regardless of industry, with mean levels prior to the 1980–1984 period of 50.4 ppm (n = 2,289), which dropped to 2.8 ppm (n = 305) in the 1990–1994 period, and to 0.1 ppm (n = 294) in the 1995–1999 period. There has been no improvement since the 2000s, when the AM(w) of 4.3 ppm (n = 6,211) for the 2005–2009 period and 4.5 ppm (n = 3,358) for the 2010–2013 period were estimated. A comparison by industry found no consistent patterns in the measurement results. Our estimated benzene measurements can be used to determine not only the possibility of retrospective exposure to benzene, but also to estimate the level of quantitative or semiquantitative retrospective exposure to benzene. PMID:26929825

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

    PubMed

    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.

  14. Benzene levels in ambient air and breath of smokers and nonsmokers in urban and pristine environments

    SciTech Connect

    Wester, R.C.; Maibach, H.I.; Gruenke, L.D.; Craig, J.C.

    1986-01-01

    Benzene levels in human breath and in ambient air were compared in the urban area of San Francisco (SF) and in a more remote coastal pristine setting of Stinson Beach, Calif. (SB). Benzene analysis was done by gas chromatography-mass spectroscopy (GC-MS). Ambient benzene levels were sevenfold higher in SF (2.6 +/- 1.3 ppb, n = 25) than SB (0.38 +/- 0.39 ppb, n = 21). In SF, benzene in smokers' breath (6.8 +/- 3.0 ppb) was greater than in nonsmokers' breath (2.5 +/- 0.8 ppb) and smokers' ambient air (3.3 +/- 0.8 ppb). In SB the same pattern was observed: benzene in smokers' breath was higher than in nonsmokers' breath and ambient air. Benzene in SF nonsmokers' breath was greater than in SB nonsmokers' breath. Marijuana-only smokers had benzene breath levels between those of smokers and nonsmokers. There was little correlation between benzene in breath and number of cigarettes smoked, or with other benzene exposures such as diet. Of special interest was the finding that benzene in breath of SF nonsmokers (2.5 +/- 0.8 ppb) was greater than that in nonsmokers ambient air (1.4 +/- 0.1 ppb). The same was true in SB, where benzene in nonsmokers breath was greater than ambient air (1.8 +/- 0.2 ppb versus 1.0 +/- 0.1 ppb on d 1 and 1.3 +/- 0.3 ppb versus 0.23 +/- 0.18 ppb on d 2). This suggests an additional source of benzene other than outdoor ambient air.

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

    PubMed Central

    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

  16. The relationship between low-level benzene exposure and leukemia in Canadian petroleum distribution workers.

    PubMed Central

    Schnatter, A R; Armstrong, T W; Thompson, L S; Nicolich, M J; Katz, A M; Huebner, W W; Pearlman, E D

    1996-01-01

    This study was conducted to evaluate the relationship between leukemia occurrence and long-term, low-level benzene exposures in petroleum distribution workers. Fourteen cases were identified among a previously studied cohort [Schnatter et al., Environ Health Perspect 101 (Suppl 6):85-89 (1993)]. Four controls per case were selected from the same cohort, controlling for birth year and time at risk. Industrial hygienists estimated workplace exposures for benzene, without knowledge of case-control status. Average benzene concentrations ranged from 0.01 to 6.2 ppm. Company medical records were used to abstract information on other potential confounders such as cigarette smoking. Odds ratios were calculated for several exposure metrics. Conditional logistic regression modeling was used to control for potential confounders. The risk of leukemia was not associated with increasing cumulative exposure to benzene for these exposure levels. Duration of benzene exposure was more closely associated with leukemia risk than other exposure metrics, although results were not statistically significant. A family history of cancer and cigarette smoking were the two strongest risk factors for leukemia, with cumulative benzene exposure showing no additional risk when considered in the same models. This study is consistent with other data in that it was unable to demonstrate a relationship between leukemia and long-term, low-level benzene exposures. The power of the study was limited. Thus, further study on benzene exposures in this concentration range are warranted. PMID:9118923

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

    PubMed

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

    2016-01-01

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

  18. Modeling Human Exposure Levels to Airborne Volatile Organic Compounds by the Hebei Spirit Oil Spill

    PubMed Central

    Kim, Jong Ho; Kwak, Byoung Kyu; Ha, Mina; Cheong, Hae-Kwan

    2012-01-01

    Objectives The goal was to model and quantify the atmospheric concentrations of volatile organic compounds (VOCs) as the result of the Hebei Spirit oil spill, and to predict whether the exposure levels were abnormally high or not. Methods We developed a model for calculating the airborne concentration of VOCs that are produced in an oil spill accident. The model was applied to a practical situation, namely the Hebei Spirit oil spill. The accuracy of the model was verified by comparing the results with previous observation data. The concentrations were compared with the currently used air quality standards. Results Evaporation was found to be 10- to 1,000-fold higher than the emissions produced from a surrounding industrial complex. The modeled concentrations for benzene failed to meet current labor environmental standards, and the concentration of benzene, toluene, ortho- meta- para-xylene were higher than the values specified by air quality standards and guideline values on the ocean. The concentrations of total VOCs were much higher than indoor environmental criteria for the entire Taean area for a few days. Conclusions The extent of airborne exposure was clearly not the same as that for normal conditions. PMID:22468262

  19. Assimilation of benzene carbon through multiple trophic levels traced by different stable isotope probing methodologies.

    PubMed

    Bastida, Felipe; Jechalke, Sven; Bombach, Petra; Franchini, Alessandro G; Seifert, Jana; von Bergen, Martin; Vogt, Carsten; Richnow, Hans H

    2011-08-01

    The flow of benzene carbon along a food chain consisting of bacteria and eukaryotes, including larvae (Diptera: Chironomidae), was evaluated by total lipid fatty acids (TLFAs)-, amino acid- and protein-stable isotope probing (SIP). A coconut-fibre textile, colonized by a benzene-degrading biofilm, was sampled in a system established for the remediation of benzene, toluene, ethylbenzene and xylenes (BTEX)-polluted groundwater and incubated with (12)C- and [(13)C(6)]-benzene (>99 at.%) in a batch-scale experiment for 2-8 days. After 8 days, Chironomus sp. larvae were added to study carbon flow to higher trophic levels. Gas chromatography-combustion-isotope ratio monitoring mass spectrometry of TLFA showed increased isotope ratios in the (13)C-benzene-incubated biofilm. A higher (13)C-enrichment was observed in TLFAs, indicative of Gram-negative bacteria than for Gram-positive. Fatty acid indicators of eukaryotes showed significant (13)C-incorporation, but to a lower extent than bacterial indicators. Fatty acids extracted from larvae feeding on (13)C-biofilm reached an isotopic ratio of 1.55 at.%, illustrating that the larvae feed, to some extent, on labelled biomass. No (13)C-incorporation was detectable in larval proteins after their separation by sodium-dodecyl sulphate-polyacrylamide gel electrophoresis and analysis by nano-liquid-chromatography-mass spectrometry. The flow of benzene-derived carbon could be traced in a food web consisting of bacteria and eukaryotes.

  20. Urinary biomarkers of exposure and of oxidative damage in children exposed to low airborne concentrations of benzene.

    PubMed

    Andreoli, R; Spatari, G; Pigini, D; Poli, D; Banda, I; Goldoni, M; Riccelli, M G; Petyx, M; Protano, C; Vitali, M; Barbaro, M; Mutti, A

    2015-10-01

    The aim of this work was to evaluate the oxidative damage to nucleic acids in children (5-11 years) associated with exposure to environmental pollutants and tobacco smoke (ETS). For each subject, urinary sampling was done twice (evening and next morning) to measure by tandem LC-MS-MS such oxidated products of nucleic acids as 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo), 8-oxo-7,8-dihydroguanosine (8-oxoGuo), and 8-oxo-7,8-dihydroguanine (8-oxoGua). Methyl tert-butyl ether (U-MTBE), benzene (U-Benz), and its metabolites (t,t-muconic and S-phenylmercapturic acids, t,t-MA and S-PMA, respectively) were determined as biomarkers of exposure to air pollution, and cotinine as a biomarker of exposure to ETS. Biomarkers of exposure (S-PMA and U-MTBE) and of DNA oxidation (8-oxodGuo) were dependent on the urbanization and industrialization levels and increased in the evening sample as compared to next morning (p<0.05). In both evening and next morning samples, 8-oxodGuo and 8-oxoGuo correlated with each other (r=0.596 and r=0.537, respectively, p<0.01) and with biomarkers of benzene exposure, particularly S-PMA (r=0.59 and r=0.45 for 8-oxodGuo and r=0.411 and r=0.383 for 8-oxoGuo, p<0.01). No such correlations were observed for U-MTBE and cotinine. Multiple linear regression analyses showed that 8-oxodGuo was positively associated with S-PMA at both sampling times (β=0.18 and β=0.14 for evening and next morning sampling, respectively; p<0.02) and weakly with U-MTBE (β=0.07, p=0.020) only in the evening urines. These results suggest that the selected biomarkers of exposure to benzene, particularly S-PMA, are good tracers of exposure to complex mixtures of oxidative pollutants and that the associated oxidative damage to nucleic acids is detectable even at very low levels of exposure.

  1. In utero exposure to benzene increases embryonic c-Myb and Pim-1 protein levels in CD-1 mice

    SciTech Connect

    Wan, Joanne; Winn, Louise M.

    2008-05-01

    Benzene is a known human leukemogen, but its role as an in utero leukemogen remains controversial. Epidemiological studies have correlated parental exposure to benzene with an increased incidence of childhood leukemias. We hypothesize that in utero exposure to benzene may cause leukemogenesis by affecting the embryonic c-Myb/Pim-1 signaling pathway and that this is mediated by oxidative stress. To investigate this hypothesis, pregnant CD-1 mice were treated with either 800 mg/kg of benzene or corn oil (i.p.) on days 10 and 11 of gestation and in some cases pretreated with 25 kU/kg of PEG-catalase. Phosphorylated and total embryonic c-Myb and Pim-1 protein levels were assessed using Western blotting and maternal and embryonic oxidative stress were assessed by measuring reduced to oxidized glutathione ratios. Our results show increased oxidative stress at 4 and 24 h after exposure, increased phosphorylated Pim-1 protein levels 4 h after benzene exposure, and increased Pim-1 levels at 24 and 48 h after benzene exposure. Embryonic c-Myb levels were elevated at 24 h after exposure. PEG-catalase pretreatment prevented benzene-mediated increases in embryonic c-Myb and Pim-1 protein levels, and benzene-induced oxidative stress. These results support a role for ROS in c-Myb and Pim-1 alterations after in utero benzene exposure.

  2. Polyphenolic metabolites in the blood and bone marrow of mice exposed to low levels of benzene

    SciTech Connect

    Bechtold, W.E.; Strunk, M.R.; Thornton-Manning, J.R.; Henderson, R.

    1996-12-31

    Exposure to benzene can cause an increased incidence of leukemia in humans, possibly through the formation of polyphenolic metabolites. To define exposure-dose relationships, male B6C3F1 mice were exposed by inhalation for 6 hr to benzene at 60 ppm or {sup 13}C-benzene at 8 ppm. Levels of phenol, catechol, and hydroquinone were measured in blood and bone marrow by gas chromatography/mass spectrometry, and compared with unexposed controls. Levels of all three metabolites, after background correction, were significantly increased in both the blood and bone marrow of the mice exposed to 60 ppm relative to those exposed to 8 ppm. However, levels of the {sup 13}C metabolites in blood and bone marrow were consistently lower than background levels of the equivalent {sup 12}C polyphenolics in unexposed controls. These results demonstrate that single exposures of benzene of less than 10 ppm add little to the blood and bone marrow burdens of polyphenolic metabolites.

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

    PubMed

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

    2015-04-01

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

  4. Airborne asbestos levels in non-occupational environments in Japan.

    PubMed

    Kohyama, N

    1989-01-01

    Airborne asbestos levels in non-occupational environments in Japan were determined by analytical transmission electron microscopy (ATEM) for about 100 air samples from various outdoor settings. Asbestos fibres (chrysotile) were found in almost all samples. The fibre (mass) concentrations were in the range of 4-367 fibres per litre (0.02-47.2 ng/m3) with a geometric mean of 18 f/1 (0.3 ng/m3). The mass concentrations were similar to the earlier data reported from other countries. Samples from main roads showed extremely high asbestos concentrations and short fibre lengths compared with those of the other samples. This strongly suggested that braking of vehicles was a significant emission source of airborne asbestos. Laboratory experiments using a brake testing machine demonstrated that asbestos fibres were released during braking. In addition, the present study found high levels of airborne asbestos in some highly polluted areas, such as a serpentine quarry, a town adjacent to an asbestos mine, and factories making asbestos slate-board. On the other hand, chrysotile fibres were also found in air samples from a small isolated island in the Pacific Ocean as well as in ice samples from ten thousand years ago in Antarctica. These facts suggest that chrysotile fibres have been liberated both by industrial activities and natural weathering, and have circulated around the earth. PMID:2744826

  5. Characterization of airborne fungal levels after mold remediation.

    PubMed

    Kleinheinz, G T; Langolf, B M; Englebert, E

    2006-01-01

    The overall objective of this project was to evaluate levels of airborne fungi present after a mold remediation project and determine the effectiveness of this remediation using airborne mold levels to determine the success of these projects. Andersen N6 (viable) and Air-O-Cell (non-viable) sampling techniques were utilized. Both test methodologies demonstrated that levels of mold in the successfully remediated portions of buildings were significantly different (p<0.05) from the levels found in non-complaint and outdoor samples from the same building, respectively. Conversely, levels in unsuccessful remediation projects were not significantly different (p>0.05) to non-complaint and outdoor samples. Both techniques showed high variability in the overall mold levels found between sites; however, the ratios of specific mold groups in each area tested, within the same site, were remarkably similar. The use of either viable or non-viable mold sampling techniques after mold remediation is essential for determining the success of such projects. This project demonstrates the relationship between mold levels and the success of a mold remediation projects, and will assist in the interpretation of data collected at the conclusion of a mold remediation project.

  6. Exposure level and distribution characteristics of airborne bacteria and fungi in Seoul metropolitan subway stations.

    PubMed

    Kim, Ki Youn; Kim, Yoon Shin; Kim, Daekeun; Kim, Hyeon Tae

    2011-01-01

    The exposure level and distribution characteristics of airborne bacteria and fungi were assessed in the workers' activity areas (station office, bedroom, ticket office and driver's seat) and passengers' activity areas (station precinct, inside the passenger carriage, and platform) of the Seoul metropolitan subway. Among investigated areas, the levels of airborne bacteria and fungi in the workers' bedroom and station precincts were relatively high. No significant difference was found in the concentration of airborne bacteria and fungi between the underground and above ground activity areas of the subway. The genera identified in all subway activity areas with a 5% or greater detection rate were Staphylococcus, Micrococcus, Bacillus and Corynebacterium for airborne bacteria and Penicillium, Cladosporium, Chrysosporium, Aspergillus for airborne fungi. Staphylococcus and Micrococcus comprised over 50% of the total airborne bacteria and Penicillium and Cladosporium comprised over 60% of the total airborne fungi, thus these four genera are the predominant genera in the subway station. PMID:21173524

  7. Controlling the levels of airborne pollen: can heterogeneous photocatalysis help?

    PubMed

    Sapiña, M; Jimenez-Relinque, E; Castellote, M

    2013-10-15

    Airborne pollen is a worldwide problem because is a very important allergenic agent; it can be altered only by certain microorganisms and by some oxidizers, such as reactive oxygen species (ROS). On the other hand, heterogeneous photocatalysis (HPC) arose as a promising technology for reducing the level of contaminants in the air, based on their degradation by the production of ROS. In this paper, study of the feasibility of HPC to diminish the counts of pollen is undertaken. The research has been carried out at different levels, from solutions to mortar specimens with the evidence that HPC is able to reduce the amount of pollen grains. This is a major breakthrough that opens the door to a whole field of research, already full of gaps, whose implications could be quite controversial.

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

    PubMed Central

    2012-01-01

    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 point source emissions

  9. Airborne Interferometry using GNSS Reflections for Surface Level Estimation

    NASA Astrophysics Data System (ADS)

    Semmling, Maximilian; Beyerle, Georg; Schön, Steffen; Stosius, Ralf; Gerber, Thomas; Beckheinrich, Jamila; Markgraf, Markus; Ge, Maorong; Wickert, Jens

    2013-04-01

    The interferometric use of GNSS reflections for ocean altimetry can fill the gap in coverage of ocean observations. Today radar altimeters are used for large scale ocean observations to monitor e.g. global sea level change or circulation processes like El Niño. Spacial and temporal resolution of a single radar altimeter, however, is insufficient to observe mesoscale ocean phenomena like large oceanic eddies that are important indicators of climate change. The high coverage expected for a spaceborne altimeter based on GNSS reflections stimulated investigations on according interferometric methods. Several airborne experiments have been conducted using code observations. Carrier observations have a better precision but are severely affected by noise and have mostly been used in ground-based experiments. A new interferometric approach is presented using carrier observations for airborne application. Implementing a spectral retrieval noise reduction is achieved. A flight experiment was conducted with a Zeppelin airship on 2010/10/12 over Lake Constance at the border between Austria, Germany and Switzerland. The lake surface with an area of 536km2 is suitable for altimetric study as its decimeter range Geoid undulations are well-known. Three GNSS receiver were installed on the airship. A Javad Delta receiver recording direct signals for navigation. The DLR G-REX receiver recording reflected signals for scatterometry and the GORS (GNSS Occultation Reflectometry Scatterometry) receiver recording direct and reflected signals for interferometry. The airship's trajectory is determined from navigation data with a precision better than 10cm using regional augmentation. This presentation focuses on the interferometric analysis of GORS observations. Ray tracing calculations are used to model the difference of direct and reflected signals' path. Spectral retrieval is applied to determine Doppler residuals of modelled path difference and interferometric observations. Lake level

  10. [A method for measuring urinary concentrations of benzene. Its use in monitoring of subjects exposed to low levels].

    PubMed

    Fiorentino, M L; Ghittori, S; Pezzagno, G

    1990-01-01

    Benzene is a widely diffuse solvent (atmosphere, cigarette smoke, some foods); in the industrial environment benzene is currently present at concentrations of ppm. A valid method of biological monitoring that is easy to perform is needed for assessing occupational and non-occupational exposures. A new method has been developed to evaluate low concentrations of benzene in urine samples by means of a "dynamic" headspace (50 ml of urine in a 120 ml vial). The urine is saturated with anhydrous Na2SO4 in order to support the entrance of benzene in the air over the urine. The solvent is stripped from the urine surface and concentrated on an adsorbent substrate (Carbotrap 100 tube) by means of a suction pump (150 ml/min). A simultaneous intake of filtered air through a charcoal tube allows wash-up of the headspace. Benzene is thermically desorbed and injected in a column (Thermal tube desorber-Supelco; 370 degrees C thermal flash; borosilicate capillary glass column SPB-1 60 m length, 0.75 mm I.D., 1 micron film thickness; G.C. Dani 8580-FID). The detection limit of the method is about 50 ng/l and the variation coefficient is 4.7%. The method was checked on urine samples of 5 non-smokers and 5 smokers: mean values of 135 and 944 ng/l respectively were obtained. A further analysis on urine samples of 60 smokers revealed a significant relationship (p less than 0.001) between urinary benzene concentrations and C0 alveolar concentrations (r = 0.626). A close relationship between benzene exposure levels and urinary concentrations was found in a group of workers exposed to low environmental benzene concentrations (mean value 1200 micrograms/m3) (r = 0.763).

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

    SciTech Connect

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

    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.

  12. Lack of sensitivity of urinary trans,trans-muconic acid in determining low-level (ppb) benzene exposure in children.

    PubMed

    Barbieri, Anna; Accorsi, Antonio; Raffi, Giovanni Battista; Nicoli, Luciana; Violante, Francesco Saverio

    2002-01-01

    Benzene is a widespread pollutant of which the main source in the outside environment is automotive traffic. Benzene is also present in cigarette smoke, and small quantities exist in drinking water and food; all of these sources contribute to pollution of indoor environments. Benzene exposure may be studied with biologic indicators. In the present study, the authors evaluated whether differences in urinary concentrations of trans,transmuconic acid (t,t-MA) were detectable in a sample of 150 children and if the chemical was correlated with environmental exposures to low levels of benzene. The children attended primary schools that had significantly different-but low-environmental benzene levels. Analysis of urinary t,t-MA was achieved with high-performance liquid chromatography (photodiode array detector), and analysis of passive air samplers for benzene was performed with gas chromatography-mass spectrometry. Statistical analysis (Kruskal-Wallis test) indicated that differences in urinary levels of t,t-MA in children from urban and rural areas were not statistically significant (p = .07), nor were there significant differences between children with and without relatives who smoked (p = .69). As has been shown in other studies of children and adults, results of our study evidenced (1) the difficulty of correlating concentrations of urinary biomarkers with environmental exposure to benzene at a parts-per-billion level (i.e., traffic and environmental tobacco smoke) and, consequently, (2) the lack of specificity of t,t-MA as a biological indicator for the study of a population's exposure. PMID:12507175

  13. Can NO(2) be used to indicate ambient and personal levels of benzene and 1,3-butadiene in air?

    PubMed

    Modig, Lars; Sunesson, Anna-Lena; Levin, Jan-Olof; Sundgren, Margit; Hagenbjörk-Gustafsson, Annika; Forsberg, Bertil

    2004-12-01

    The aim of this study was to investigate the relation between two toxic volatile organic compounds, 1,3-butadiene and benzene, and a commonly used indicator of vehicle exhaust fumes, NO(2). This was to see if NO(2) can be used to indicate personal exposure to carcinogenic substances or at least estimate ambient levels measured at a stationary point. During the winter of 2001, 40 randomly selected persons living in the City of Umea (in the north of Sweden) were recruited to the study. Personal measurements of 1,3-butadiene, benzene and NO(2) were performed for one week, and were repeated for 20 of the 40 participants. Additional information was gathered using a diary kept by each participant. During the same time period weekly stationary measurements were performed at one urban background station and one street station in the city centre. The results from the personal measurements showed a negligible association of NO(2) with 1,3-butadiene (r= 0.06) as well as with benzene (r= 0.10), while the correlation coefficient between 1,3-butadiene and benzene was high and significant (r= 0.67). In contrast to the personal measurements, the stationary measurements showed strong relations between 1,3-butadiene, benzene and NO(2) both within and in-between the street and urban background station. This study supports NO(2) as a potential indicator for 1,3-butadiene and benzene levels in streets or urban background air, while the weak relations found for the personal measurements do not support the use of NO(2) as an indicator for personal 1,3-butadiene and benzene exposure. PMID:15568043

  14. Combining regression analysis and air quality modelling to predict benzene concentration levels

    NASA Astrophysics Data System (ADS)

    Vlachokostas, Ch.; Achillas, Ch.; Chourdakis, E.; Moussiopoulos, N.

    2011-05-01

    State of the art epidemiological research has found consistent associations between traffic-related air pollution and various outcomes, such as respiratory symptoms and premature mortality. However, many urban areas are characterised by the absence of the necessary monitoring infrastructure, especially for benzene (C 6H 6), which is a known human carcinogen. The use of environmental statistics combined with air quality modelling can be of vital importance in order to assess air quality levels of traffic-related pollutants in an urban area in the case where there are no available measurements. This paper aims at developing and presenting a reliable approach, in order to forecast C 6H 6 levels in urban environments, demonstrated for Thessaloniki, Greece. Multiple stepwise regression analysis is used and a strong statistical relationship is detected between C 6H 6 and CO. The adopted regression model is validated in order to depict its applicability and representativeness. The presented results demonstrate that the adopted approach is capable of capturing C 6H 6 concentration trends and should be considered as complementary to air quality monitoring.

  15. Benzene exposure, assessed by urinary trans,trans-muconic acid, in urban children with elevated blood lead levels.

    PubMed Central

    Weaver, V M; Davoli, C T; Heller, P J; Fitzwilliam, A; Peters, H L; Sunyer, J; Murphy, S E; Goldstein, G W; Groopman, J D

    1996-01-01

    A pilot study was performed to evaluate the feasibility of using trans,trans-muconic acid (MA) as a biomarker of environmental benzene exposure. A secondary aim was to provide data on the extent of exposure to selected toxicants in a unique population consisting of inner-city children who were already overexposed to one urban hazard, lead. Potential sources of benzene were assessed by a questionnaire. Exposure biomarkers included urinary MA and cotinine and blood lead. Mean MA was 176.6 +/- 341.7 ng/mg creatinine in the 79 children who participated. A wide range of values was found with as many as 10.1%, depending on the comparison study, above the highest levels reported in adults not exposed by occupation. Mean MA was increased in children evaluated in the afternoon compared to morning, those at or above the median for time spent playing near the street, and those studied in the first half of the investigation. MA levels were not associated with blood lead or, consistently, with either questionnaire environmental tobacco smoke (ETS) data or cotinine. As expected, the mean blood lead level was elevated (23.6 micrograms/dl). Mean cotinine was also increased at 79.2 ng/mg creatinine. We conclude that the use of MA as a biomarker for environmental benzene exposure is feasible since it was detectable in 72% of subjects with a wide range of values present. In future studies, correlation of MA with personal air sampling in environmental exposure will be essential to fully interpret the significance of these findings. In addition, these inner-city children comprise a high risk group for exposure to environmental toxicants including ETS, lead, and probably benzene, based on questionnaire sources and its presence in ETS. Images Figure 1. Figure 2. Figure 3. Figure 4. Figure 4. Figure 5. PMID:8919771

  16. The mutagenic effects of low level sub-acute inhalation exposure to benzene in CD-1 mice.

    PubMed

    Ward, J B; Ammenheuser, M M; Ramanujam, V M; Morris, D L; Whorton, E B; Legator, M S

    1992-07-01

    Benzene is a widely used chemical and common environmental contaminant. It is carcinogenic in man and animals and is genotoxic in mice, rats, and occupationally exposed humans at doses above one part per million. In order to evaluate the genotoxic effects of prolonged exposures to very low concentrations of benzene, we exposed CD-1 mice to benzene by inhalation for 22 h per day, seven days per week for six weeks at 40, 100 and 1000 parts per billion (ppb). Additional groups were exposed to purified air or were housed in standard plastic cages. The effects of in vivo exposure to benzene were evaluated by using an autoradiographic assay to determine the frequency of mutants which represent mutations at the hypoxanthine-guanine phosphoribosyl transferase (hprt) locus in spleen lymphocytes. At the end of the six weeks exposure period lymphocytes were recovered from the spleens of the mice and cryopreserved prior to assay. Mutant cells were selected on the basis of their ability to incorporate tritiated thymidine in the presence of 6-thioguanine. The weighted mean variant (mutant) frequencies (Vf) of female mice (three per group) were 7.2 x 10(-6) at 0 ppb; 29.2 x 10(-6) at 40 ppb; 62.5 x 10(-6) at 100 ppb and 25.0 x 10(-6) at 1000 ppb. The Vf of unexposed mice housed in standard cages was 13.2 x 10(-6). In male mice the same pattern of response was observed, but the increases in Vf in response to benzene were not as great. In both sexes of mice, the increases at 40 and 100 ppb were significantly greater than at 0 ppb (P less than 0.05). The increase in Vf with exposure to 100 ppb and the decline at 1000 ppb parallel the results observed for chromosome damage in spleen lymphocytes from the same animals (Au et al., Mutation Res., 260 (1991) 219-224). These results indicate that sub-chronic exposure to benzene at levels below the current Occupational Safety and Health Administration Permitted Exposure Limit may induce gene mutations in lymphocytes in mice.

  17. Airborne determination of the temporo-spatial distribution of benzene, toluene, nitrogen oxides and ozone in the boundary layer across Greater London, UK

    NASA Astrophysics Data System (ADS)

    Shaw, M. D.; Lee, J. D.; Davison, B.; Vaughan, A.; Purvis, R. M.; Harvey, A.; Lewis, A. C.; Hewitt, C. N.

    2015-05-01

    Highly spatially resolved mixing ratios of benzene and toluene, nitrogen oxides (NOx) and ozone (O3) were measured in the atmospheric boundary layer above Greater London during the period 24 June to 9 July 2013 using a Dornier 228 aircraft. Toluene and benzene were determined in situ using a proton transfer reaction mass spectrometer (PTR-MS), NOx by dual-channel NOx chemiluminescence and O3 mixing ratios by UV absorption. Average mixing ratios observed over inner London at 360 ± 10 m a.g.l. were 0.20 ± 0.05, 0.28 ± 0.07, 13.2 ± 8.6, 21.0 ± 7.3 and 34.3 ± 15.2 ppbv for benzene, toluene, NO, NO2 and NOx respectively. Linear regression analysis between NO2, benzene and toluene mixing ratios yields a strong covariance, indicating that these compounds predominantly share the same or co-located sources within the city. Average mixing ratios measured at 360 ± 10 m a.g.l. over outer London were always lower than over inner London. Where traffic densities were highest, the toluene / benzene (T / B) concentration ratios were highest (average of 1.8 ± 0.5 ppbv ppbv-1), indicative of strong local sources. Daytime maxima in NOx, benzene and toluene mixing ratios were observed in the morning (~ 40 ppbv NOx, ~ 350 pptv toluene and ~ 200 pptv benzene) and in the mid-afternoon for ozone (~ 40 ppbv O3), all at 360 ± 10 m a.g.l.

  18. Airborne determination of the temporo-spatial distribution of benzene, toluene, nitrogen oxides and ozone in the boundary layer across Greater London, UK

    NASA Astrophysics Data System (ADS)

    Shaw, M. D.; Lee, J. D.; Davison, B.; Vaughan, A.; Purvis, R. M.; Lewis, A. C.; Hewitt, C. N.

    2014-10-01

    Highly spatially resolved mixing ratios of benzene and toluene, nitrogen oxides (NOx) and ozone (O3) were measured in the atmospheric boundary layer above Greater London during the period 24 June to 9 July 2013 using a Dornier 228 aircraft. Toluene and benzene were determined in-situ using a proton transfer reaction mass spectrometer (PTR-MS), NOx by dual channel NOx chemiluminescence and O3 mixing ratios by UV absorption. Average mixing ratios observed over inner London at 360 ± 10 m a.g.l. were 0.20 ± 0.05, 0.28 ± 0.07, 13.2 ± 8.6, 21.0 ± 7.3 and 34.3 ± 15.2 ppbv for benzene, toluene, NO, NO2 and NOx respectively. Linear regression analysis between NO2, benzene and toluene mixing ratios yielded a trimodal distribution indicating that these compounds predominantly share the same or co-located sources within the city and that a significant fraction of NOx is directly emitted as NO2. Average mixing ratios measured at 360 ± 10 m a.g.l. over outer London were always lower than over inner London. Where traffic densities were highest, the toluene / benzene (T / B) concentration ratios were highest (average of 1.8 ± 0.3 ppbv ppbv-1) indicative of strong local sources. Daytime maxima in NOx, benzene and toluene mixing ratios were observed in the morning (~40 ppbv NOx, ~350 pptv toluene and ~200 pptv benzene) and for ozone in the mid-afternoon (~40 ppbv O3) all at 360 ± 10 m a.g.l.

  19. van der Waals rovibration levels and the high resolution spectrum of the argon-benzene dimer

    NASA Astrophysics Data System (ADS)

    van der Avoird, Ad

    1993-04-01

    The van der Waals vibrations of Ar-benzene are calculated from two different intermolecular potentials, which are analytic fits to the same ab initio potential. The rovibrational Hamiltonian was derived earlier; the wave functions of the large amplitude vibrations are expanded in products of harmonic oscillator functions. The rotational structure of each van der Waals state is obtained from perturbation theory, as well as from variational calculations of the complete rovibrational states for J=0, 1, and 2. The degenerate bending modes and combinations have a large vibrational angular momentum; for their rotational structure it is important to include all first, second, and higher order rovibrational (Coriolis) coupling. The calculated vibrational frequencies, the information about rovibrational coupling, and the PI(C6v) selection rules for van der Waals transitions, in combination with the vibronic 601 transition on the benzene monomer, lead to a partially new assignment of the three van der Waals sidebands observed in high resolution UV spectra.

  20. Low level detection of Benzene in Food Grade Hexane by Ultraviolet Spectrophotometry.

    PubMed

    Emmandi, R; Sastry, M I S; Patel, M B

    2014-10-15

    A simple, sensitive, and accurate Ultraviolet Spectrophotometric method has been developed and validated for the determination of Benzene in Food Grade Hexane. Benzene in spectroscopic grade Hexane shows vibrational fine structure having four well resolved peaks. In the wavelength range 240-270nm, peak at 255nm is considered for the method development. Beer's law was obeyed in the concentration range of 0.6-10.0μLL(-1), with correlation coefficient, 0.9999, detection limit 0.2μLL(-1) and quantitation limit 0.6μLL(-1) are established. Percentage recovery studies showed that the method was not affected by the presence of other solvents having the similar boiling range with Hexane. The method was validated by determining its accuracy and precision which proves suitability of the developed method for the routine determination of Benzene in Food Grade Hexane. The proposed method has been applied successfully for the analysis of the Food Grade Hexane.

  1. Trends of PCB, hexachlorobenzene, and. beta. -benzene hexachloride levels in the adipose tissue of the U. S. population

    SciTech Connect

    Robinson, P.E.; Remmers, J. ); Mack, G.A. ); Levy, R. ); Mohadjer, L. )

    1990-12-01

    Results are presented on the levels of selected toxic chemicals in the adipose tissue of the U.S. population. Estimates of baseline levels and time trends are presented for the chemicals {beta}-benzene hexachloride ({beta}-BHC), hexachlorobenzene, and polychlorinated biphenyls (PCBs). The statistical analyses are based on chemical data obtained from analysis of tissue specimens collected from a nationally representative sample of autopsied cadavers and surgical patients by EPA's National Human Adipose Tissue Survey during the period 1970 through 1983. The results show that while nearly the entire U.S. population has detectable levels of these chemicals, the actual concentration levels of {beta}-BHC and PCBs are steadily decreasing and the levels of HCB are remaining fairly constant. Comparisons of levels across demographic subpopulations show that there are some differences in concentration levels across geographic regions, age groups, and race groups.

  2. Benzene and human health: A historical review and appraisal of associations with various diseases.

    PubMed

    Galbraith, David; Gross, Sherilyn A; Paustenbach, Dennis

    2010-11-01

    Over the last century, benzene has been a well-studied chemical, with some acute and chronic exposures being directly associated with observed hematologic effects in humans and animals. Chronic heavy exposures to benzene have also been associated with acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS) in humans. Other disease processes have also been studied, but have generally not been supported by epidemiologic studies of workers using benzene in the workplace. Within occupational cohorts with large populations and very low airborne benzene exposures (less than 0.1–1.0 ppm), it can be difficult to separate background disease incidence from those occurring due to occupational exposures. In the last few decades, some scientists and physicians have suggested that chronic exposures to various airborne concentrations of benzene may increase the risk of developing non-Hodgkin's lymphoma (NHL) (Savitz and Andrews, 1997, Am J Ind Med 31:287–295; Smith et al., 2007, Cancer Epidemiol Biomarkers Prev 16:385–391), multiple myeloma (MM) (Goldstein, 1990, Ann NY Acad Sci 609:225–230; Infante, 2006, Ann NY Acad Sci 1076:90–109), and various other hematopoietic disorders. We present a state-of-the-science review of the medical and regulatory aspects regarding the hazards of occupational exposure to benzene. We also review the available scientific and medical evidence relating to benzene and the risk of developing various disorders following specific levels of exposure. Our evaluation indicates that the only malignant hematopoietic disease that has been clearly linked to benzene exposure is AML. Information from the recent "Benzene 2009," a symposium of international experts focusing on the health effects and mechanisms of toxicity of benzene, hosted by the Technical University of Munich, has been incorporated and referenced.

  3. Predicting Airborne Particle Levels Aboard Washington State School Buses.

    PubMed

    Adar, Sara D; Davey, Mark; Sullivan, James R; Compher, Michael; Szpiro, Adam; Liu, L-J Sally

    2008-10-01

    School buses contribute substantially to childhood air pollution exposures yet they are rarely quantified in epidemiology studies. This paper characterizes fine particulate matter (PM(2.5)) aboard school buses as part of a larger study examining the respiratory health impacts of emission-reducing retrofits.To assess onboard concentrations, continuous PM(2.5) data were collected during 85 trips aboard 43 school buses during normal driving routines, and aboard hybrid lead vehicles traveling in front of the monitored buses during 46 trips. Ordinary and partial least square regression models for PM(2.5) onboard buses were created with and without control for roadway concentrations, which were also modeled. Predictors examined included ambient PM(2.5) levels, ambient weather, and bus and route characteristics.Concentrations aboard school buses (21 mug/m(3)) were four and two-times higher than ambient and roadway levels, respectively. Differences in PM(2.5) levels between the buses and lead vehicles indicated an average of 7 mug/m(3) originating from the bus's own emission sources. While roadway concentrations were dominated by ambient PM(2.5), bus concentrations were influenced by bus age, diesel oxidative catalysts, and roadway concentrations. Cross validation confirmed the roadway models but the bus models were less robust.These results confirm that children are exposed to air pollution from the bus and other roadway traffic while riding school buses. In-cabin air pollution is higher than roadway concentrations and is likely influenced by bus characteristics.

  4. Predicting Airborne Particle Levels Aboard Washington State School Buses

    PubMed Central

    Adar, Sara D.; Davey, Mark; Sullivan, James R.; Compher, Michael; Szpiro, Adam; Liu, L.-J. Sally

    2008-01-01

    School buses contribute substantially to childhood air pollution exposures yet they are rarely quantified in epidemiology studies. This paper characterizes fine particulate matter (PM2.5) aboard school buses as part of a larger study examining the respiratory health impacts of emission-reducing retrofits. To assess onboard concentrations, continuous PM2.5 data were collected during 85 trips aboard 43 school buses during normal driving routines, and aboard hybrid lead vehicles traveling in front of the monitored buses during 46 trips. Ordinary and partial least square regression models for PM2.5 onboard buses were created with and without control for roadway concentrations, which were also modeled. Predictors examined included ambient PM2.5 levels, ambient weather, and bus and route characteristics. Concentrations aboard school buses (21 μg/m3) were four and two-times higher than ambient and roadway levels, respectively. Differences in PM2.5 levels between the buses and lead vehicles indicated an average of 7 μg/m3 originating from the bus's own emission sources. While roadway concentrations were dominated by ambient PM2.5, bus concentrations were influenced by bus age, diesel oxidative catalysts, and roadway concentrations. Cross validation confirmed the roadway models but the bus models were less robust. These results confirm that children are exposed to air pollution from the bus and other roadway traffic while riding school buses. In-cabin air pollution is higher than roadway concentrations and is likely influenced by bus characteristics. PMID:18985175

  5. Facts about Benzene

    MedlinePlus

    ... of benzene from tobacco smoke, gas stations, motor vehicle exhaust, and industrial emissions. Indoor air generally contains ... to anemia. Also, it can damage the immune system by changing blood levels of antibodies and causing ...

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

    PubMed Central

    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. At the highest exposure concentration, rats exhaled approximately half of the internal dose retained at the end of the 6-hr exposure as benzene; mice exhaled only 15% as benzene. Mice were able to convert more of the inhaled benzene to metabolites than were rats. In addition, mice metabolized more of the benzene by pathways leading to the putative toxic metabolites, benzoquinone and muconaldehyde, than did rats. In both rats and mice, the effect of increasing dose, administered orally or by inhalation, was to increase the proportion of the total metabolites that were the products of detoxification pathways relative to the products of pathways leading to putative toxic metabolites. This indicates low-affinity, high-capacity pathways for detoxification and high-affinity, low-capacity pathways leading to putative toxic metabolites. If the results of rodent studies performed at high doses were used to assess the health risk at low-dose exposures to benzene, the toxicity of benzene would be underestimated. PMID:2792053

  7. Benzene poisoning

    MedlinePlus

    ... Atlanta, GA. Mirkin DB. Benzene and related aromatic hydrocarbons. In: Shannon MW, Borron SW, Burns MJ, eds. ... PA: Elsevier Saunders; 2007:chap 94. Lee DC. Hydrocarbons. In: Marx JA, Hockberger RS, Walls RM, et ...

  8. trans,trans-Muconic acid, a reliable biological indicator for the detection of individual benzene exposure down to the ppm level.

    PubMed

    Ducos, P; Gaudin, R; Bel, J; Maire, C; Francin, J M; Robert, A; Wild, P

    1992-01-01

    trans,trans-Muconic acid (2,4-hexadienedioic acid) (t,t-MA) is a minor benzene metabolite which can be used as a biological indicator for benzene exposure. The purpose of the study was to evaluate the limits of use of t,t-MA for detection and quantification of occupational exposures to benzene, particularly on an individual scale, phenol being used as the metabolite of reference. A simple and sensitive method previously described by the authors was carried out to analyse t,t-MA in 105 end-of-shift urinary samples from 23 workers exposed to benzene used as an extraction solvent for "concretes" recovery in the perfume industry. Good correlations were found between atmospheric benzene and both metabolites (uncorrected or corrected for creatinine) or between the metabolites themselves, with correlation coefficients from 0.81 to 0.91 (P < 0.0001). Correlation- coefficients were not improved after correction for creatinine. The overall individual benzene exposure range, median, and arithmetic mean were respectively 0.1-75, 4.5, and 9.0 ppm with corresponding t,t-MA excretion of 0.1-47.9, 5.2 and 8.9 mg/l (uncorrected) and phenol excretion of 1.4-298, 30.9, and 42.2 mg/l (uncorrected). In the control group (145 determinations for t,t-MA and 76 for phenol from 79 individuals) the range, median, and arithmetic mean were respectively < 0.04-0.66, 0.08, and 0.13 mg/l (uncorrected t,t-MA) and 1.5-42.0, 9.85 and 11.3 mg/l (uncorrected phenol). t,t-MA was far more specific than phenol and could be easily and practically used to estimate with a given probability the upper or lower corresponding benzene concentrations down to around the ppm level.(ABSTRACT TRUNCATED AT 250 WORDS)

  9. Synthesis and characterization of composite polymer, polyethylene glycol grafted flower-like cupric nano oxide for solid phase microextraction of ultra-trace levels of benzene, toluene, ethyl benzene and o-xylene in human hair and water samples.

    PubMed

    Sarafraz-Yazdi, Ali; Zendegi-Shiraz, Amene; Es'haghi, Zarrin; Hassanzadeh-Khayyat, Mohammad

    2015-10-30

    In this research, poly (ethylene glycol)-poly (ethylene glycol) grafted flower-like cupric oxidenano particles (PEG-PEG-g-CuO NPs) as a novel fiber coating of solid-phase microextraction (SPME) were synthesized by using sol-gel technology. This fiber was successfully applied to extract and determine the ultra-trace levels of benzene, toluene, ethyl benzene and o-xylene in human hair using head space-solid-phase microextraction (HS-SPME) coupled to gas chromatography-flame ionization detector. Characterization and chemical composition of the nano particle was performed by Fourier transform infrared spectroscopy (FT-IR), energy dispersion spectroscopy (EDS) and back scatter analysis (BSA). These methods confirmed the successful fabrication of PEG-g-CuO NPs. The surface morphology of the fibers were inspected by scanning electron microscopy. The scanning electron microscopy (SEM) revealed many "crack-like" features and highly porous structure on the surface of fiber. The synthesized nanocomposites were used for preconcentration and extraction of benzene, toluene, ethyl benzene and o-xylene (BTEX). The effects of operating parameters such as: desorption temperature and time, extraction temperature, extraction time, stirring speed and salt effect were investigated and optimized. Under the optimal conditions, the method detection limits and the limits of quantification were between 0.00025-50.00000pgmL(-1) and 0.00200-200.00000pgmL(-1), respectively. Linearity was observed over a range 0.00200-200000.00000pgmL(-1). The relative standard deviations for one fiber (repeatability; n=5) were obtained from 3.30 up to 5.01% and between fibers or batch to batch (n=3; reproducibility) in the range of 3.63-6.21%. The developed method was successfully applied to simultaneous determination of BTEX in human hairs, tap water and distillate water. PMID:26411479

  10. Synthesis and characterization of composite polymer, polyethylene glycol grafted flower-like cupric nano oxide for solid phase microextraction of ultra-trace levels of benzene, toluene, ethyl benzene and o-xylene in human hair and water samples.

    PubMed

    Sarafraz-Yazdi, Ali; Zendegi-Shiraz, Amene; Es'haghi, Zarrin; Hassanzadeh-Khayyat, Mohammad

    2015-10-30

    In this research, poly (ethylene glycol)-poly (ethylene glycol) grafted flower-like cupric oxidenano particles (PEG-PEG-g-CuO NPs) as a novel fiber coating of solid-phase microextraction (SPME) were synthesized by using sol-gel technology. This fiber was successfully applied to extract and determine the ultra-trace levels of benzene, toluene, ethyl benzene and o-xylene in human hair using head space-solid-phase microextraction (HS-SPME) coupled to gas chromatography-flame ionization detector. Characterization and chemical composition of the nano particle was performed by Fourier transform infrared spectroscopy (FT-IR), energy dispersion spectroscopy (EDS) and back scatter analysis (BSA). These methods confirmed the successful fabrication of PEG-g-CuO NPs. The surface morphology of the fibers were inspected by scanning electron microscopy. The scanning electron microscopy (SEM) revealed many "crack-like" features and highly porous structure on the surface of fiber. The synthesized nanocomposites were used for preconcentration and extraction of benzene, toluene, ethyl benzene and o-xylene (BTEX). The effects of operating parameters such as: desorption temperature and time, extraction temperature, extraction time, stirring speed and salt effect were investigated and optimized. Under the optimal conditions, the method detection limits and the limits of quantification were between 0.00025-50.00000pgmL(-1) and 0.00200-200.00000pgmL(-1), respectively. Linearity was observed over a range 0.00200-200000.00000pgmL(-1). The relative standard deviations for one fiber (repeatability; n=5) were obtained from 3.30 up to 5.01% and between fibers or batch to batch (n=3; reproducibility) in the range of 3.63-6.21%. The developed method was successfully applied to simultaneous determination of BTEX in human hairs, tap water and distillate water.

  11. Effect of CYP2E1 induction by ethanol on the immunotoxicity and genotoxicity of extended low-level benzene exposure.

    PubMed

    Daiker, D H; Shipp, B K; Schoenfeld, H A; Klimpel, G R; Witz, G; Moslen, M T; Ward, J B

    2000-02-11

    Potential additive effects of ethanol consumption, a common life-style factor, and low-level benzene exposure, a ubiquitous environmental pollutant, were investigated. Ethanol is a potent inducer of the cytochrome P-450 2E1 (CYP2E1) enzyme, which bioactivates benzene to metabolites with known genotoxicity and immunotoxicity. A liquid diet containing 4.1% ethanol was used to induce hepatic CYP2E1 activity by 4-fold in female CD-1 mice. Groups of ethanol-treated or pair-fed control mice were exposed to benzene or filtered air in inhalation chambers for 7 h/d, 5 d/wk for 6 or 11 wk. The initial experiment focused on immunotoxicity endpoints based on literature reports that ethanol enhances high-dose benzene effects on spleen, thymus, and bone marrow cellularity and on peripheral red blood cell (RBC) and white blood cell (WBC) counts. No statistically significant alterations were found in spleen lymphocyte cellularity, subtype profile, or function (mitogen-induced proliferation, cytokine production, or natural killer cell lytic activity) after 6 wk of ethanol diet, 0.44 ppm benzene exposure, or both. This observed absence of immunomodulation by ethanol alone, a potential confounding factor, further validates our previously established murine model of sustained CYP2E1 induction by dietary ethanol. Subsequent experiments involved a 10-fold higher benzene level for a longer time of 11 wk and focused on genotoxic endpoints in known target tissues. Bone marrow and spleen cells were evaluated for DNA-protein cross-links, a sensitive transient index of genetic damage, and spleen lymphocytes were monitored for hprt-mutant frequency, a biomarker of cumulative genetic insult. No treatment-associated changes in either genotoxic endpoint were detected in animals exposed to 4.4 ppm benzene for 6 or 11 wk with or without coexposure to ethanol. Thus, our observations suggest an absence of genetic toxicity in CD-1 mice exposed to environmentally relevant levels of benzene with or

  12. [Remote sensing of chlorophyll fluorescence at airborne level based on unmanned airship platform and hyperspectral sensor].

    PubMed

    Yang, Pei-Qi; Liu, Zhi-Gang; Ni, Zhuo-Ya; Wang, Ran; Wang, Qing-Shan

    2013-11-01

    The solar-induced chlorophyll fluorescence (ChlF) has a close relationship with photosynthetic and is considered as a probe of plant photosynthetic activity. In this study, an airborne fluorescence detecting system was constructed by using a hyperspectral imager on board an unmanned airship. Both Fraunhofer Line Discriminator (FLD) and 3FLD used to extract ChlF require the incident solar irradiance, which is always difficult to receive at airborne level. Alternative FLD (aFLD) can overcome the problem by selecting non-fluorescent emitter in the image. However, aFLD is based on the assumption that reflectance is identical around the Fraunhofer line, which is not realistic. A new method, a3FLD, is proposed, which assumes that reflectance varies linearly with the wavelength around Fraunhofer line. The result of simulated data shows that ChlF retrieval error of a3FLD is significantly lower than that of aFLD when vegetation reflectance varies near the Fraunhofer line. The results of hyperspectral remote sensing data with the airborne fluorescence detecting system show that the relative values of retrieved ChlF of 5 kinds of plants extracted by both aFLD and a3FLD are consistent with vegetation growth stage and the ground-level ChlF. The ChlF values of aFLD are about 15% greater than a3FLD. In addition, using aFLD, some non-fluorescent objects have considerable ChlF value, while a3FLD can effectively overcome the problem.

  13. [Remote sensing of chlorophyll fluorescence at airborne level based on unmanned airship platform and hyperspectral sensor].

    PubMed

    Yang, Pei-Qi; Liu, Zhi-Gang; Ni, Zhuo-Ya; Wang, Ran; Wang, Qing-Shan

    2013-11-01

    The solar-induced chlorophyll fluorescence (ChlF) has a close relationship with photosynthetic and is considered as a probe of plant photosynthetic activity. In this study, an airborne fluorescence detecting system was constructed by using a hyperspectral imager on board an unmanned airship. Both Fraunhofer Line Discriminator (FLD) and 3FLD used to extract ChlF require the incident solar irradiance, which is always difficult to receive at airborne level. Alternative FLD (aFLD) can overcome the problem by selecting non-fluorescent emitter in the image. However, aFLD is based on the assumption that reflectance is identical around the Fraunhofer line, which is not realistic. A new method, a3FLD, is proposed, which assumes that reflectance varies linearly with the wavelength around Fraunhofer line. The result of simulated data shows that ChlF retrieval error of a3FLD is significantly lower than that of aFLD when vegetation reflectance varies near the Fraunhofer line. The results of hyperspectral remote sensing data with the airborne fluorescence detecting system show that the relative values of retrieved ChlF of 5 kinds of plants extracted by both aFLD and a3FLD are consistent with vegetation growth stage and the ground-level ChlF. The ChlF values of aFLD are about 15% greater than a3FLD. In addition, using aFLD, some non-fluorescent objects have considerable ChlF value, while a3FLD can effectively overcome the problem. PMID:24555390

  14. Quantitative analysis of trace-level benzene, toluene, ethylbenzene, and xylene in cellulose acetate tow using headspace heart-cutting multidimensional gas chromatography with mass spectrometry.

    PubMed

    Ji, Xiaorong; Zhang, Jing; Guo, Yinlong

    2016-06-01

    This study describes a method for the quantification of trace-level benzene, toluene, ethylbenzene, and xylene in cellulose acetate tow by heart-cutting multidimensional gas chromatography with mass spectrometry in selected ion monitoring mode. As the major volatile component in cellulose acetate tow samples, acetone would be overloaded when attempting to perform a high-resolution separation to analyze trace benzene, toluene, ethylbenzene, and xylene. With heart-cutting technology, a larger volume injection was achieved and acetone was easily cut off by employing a capillary column with inner diameter of 0.32 mm in the primary gas chromatography. Only benzene, toluene, ethylbenzene, and xylene were directed to the secondary column to result in an effective separation. The matrix interference was minimized and the peak shapes were greatly improved. Finally, quantitative analysis of benzene, toluene, ethylbenzene, and xylene was performed using an isotopically labeled internal standard. The headspace multidimensional gas chromatography mass spectrometry system was proved to be a powerful tool for analyzing trace volatile organic compounds in complex samples.

  15. Harvesting tree biomass at the stand level to assess the accuracy of field and airborne biomass estimation in savannas.

    PubMed

    Colgan, Matthew S; Asner, Gregory P; Swemmer, Tony

    2013-07-01

    Tree biomass is an integrated measure of net growth and is critical for understanding, monitoring, and modeling ecosystem functions. Despite the importance of accurately measuring tree biomass, several fundamental barriers preclude direct measurement at large spatial scales, including the facts that trees must be felled to be weighed and that even modestly sized trees are challenging to maneuver once felled. Allometric methods allow for estimation of tree mass using structural characteristics, such as trunk diameter. Savanna trees present additional challenges, including limited available allometry and a prevalence of multiple stems per individual. Here we collected airborne lidar data over a semiarid savanna adjacent to the Kruger National Park, South Africa, and then harvested and weighed woody plant biomass at the plot scale to provide a standard against which field and airborne estimation methods could be compared. For an existing airborne lidar method, we found that half of the total error was due to averaging canopy height at the plot scale. This error was eliminated by instead measuring maximum height and crown area of individual trees from lidar data using an object-based method to identify individual tree crowns and estimate their biomass. The best object-based model approached the accuracy of field allometry at both the tree and plot levels, and it more than doubled the accuracy compared to existing airborne methods (17% vs. 44% deviation from harvested biomass). Allometric error accounted for less than one-third of the total residual error in airborne biomass estimates at the plot scale when using allometry with low bias. Airborne methods also gave more accurate predictions at the plot level than did field methods based on diameter-only allometry. These results provide a novel comparison of field and airborne biomass estimates using harvested plots and advance the role of lidar remote sensing in savanna ecosystems.

  16. Metabolic polymorphisms and biomarkers of effect in the biomonitoring of occupational exposure to low-levels of benzene: state of the art.

    PubMed

    De Palma, G; Manno, M

    2014-12-01

    Current levels of occupational exposure to benzene, a genotoxic human carcinogen, in Western countries are reduced by two-three orders of magnitude (from ppm to ppb) as compared to the past. However, as benzene toxicity is strongly dependent on biotransformation and recent evidence underlines a higher efficiency of bio-activation pathways at lower levels of exposure, toxic effects at low doses could be higher than expected, particularly in susceptible individuals. Currently, biological monitoring can allow accurate exposure assessment, relying on sensitive and specific enough biomarkers of internal dose. The availability of similarly reliable biomarkers of early effect or susceptibility could greatly improve the risk assessment process to such an extent that risk could even be assessed at the individual level. As to susceptibility biomarkers, functional genetic polymorphisms of relevant biotransformation enzymes may modulate the risk of adverse effects (NQO1) and the levels of biomarkers of internal dose, in particular S-phenylmercapturic acid (GSTM1, GSTT1, GSTA1). Among biomarkers of early effect, genotoxicity indicators, although sensitive in some cases, are too aspecific for routine use in occupational health surveillance programmes. Currently only the periodical blood cell count seems suitable enough to be applied in the longitudinal monitoring of effects from benzene exposure. Novel biomarkers of early effect are expected from higher collaboration among toxicologists and clinicians, also using advanced "omics" techniques.

  17. Air modelling as an alternative to sampling for low-level radioactive airborne releases

    SciTech Connect

    Morgenstern, M.Y.; Hueske, K.

    1995-05-01

    This paper describes our efforts to assess the effect of airborne releases at one DOE laboratory using air modelling based on historical data. Among the facilities affected by these developments is Los Alamos National Laboratory (LANL) in New Mexico. RCRA, as amended by the Hazardous and Solid Waste Amendments (HSWA) in 1984, requires all facilities which involve the treatment, storage, and disposal of hazardous waste obtain a RCRA/HSWA waste facility permit. LANL complied with CEARP by initiating a process of identifying potential release sites associated with LANL operations prior to filing a RCRA/HSWA permit application. In the process of preparing the RCRA/HSWA waste facility permit application to the U.S. Environmental Protection Agency (EPA), a total of 603 Solid Waste Management Units (SWMUs) were identified as part of the requirements of the HSWA Module VIH permit requirements. The HSWA Module VIII permit requires LANL to determine whether there have been any releases of hazardous waste or hazardous constituents from SWMUs at the facility dating from the 1940`s by performing a RCRA Facility Investigation to address known or suspected releases from specified SWMUs to affected media (i.e. soil, groundwater, surface water, and air). Among the most troublesome of the potential releases sites are those associated with airborne radioactive releases. In order to assess health risks associated with radioactive contaminants in a manner consistent with exposure standards currently in place, the DOE and LANL have established Screening Action Levels (SALs) for radioactive soil contamination. The SALs for each radionuclide in soil are derived from calculations based on a residential scenario in which individuals are exposed to contaminated soil via inhalation and ingestion as well as external exposure to gamma emitters in the soil. The applicable SALs are shown.

  18. High levels of airborne ultrafine and fine particulate matter in indoor ice arenas.

    PubMed

    Rundell, Kenneth W

    2003-03-01

    The high prevalence of airway dysfunction among ice arena athletes may be related to rink air exposure; in particular, high concentrations of ultrafine and fine particulate matter (0.02-1.0 micro m diameter, PM(1)) from ice resurfacing machines may enhance airway inflammation and hyperreactivity. The purpose of this study was to identify levels of PM(1) emitted from ice resurfacing machines used in indoor ice arenas, and to compare [PM(1)] pre- and post-resurfacing to each other and to outdoor [PM(1)]. Multiple one Hz measurements were recorded on 28 different days as 15-s mean of PM(1).cm(-3) for 2 min at 1-1.5 m "above ice" in 10 rinks pre- and post-resurfacing, with measured airborne PM(1) outside each rink to be used individual rink references. Rink PM(1).cm(-3) was approximately 30 times greater than PM(1).cm(-3) outside the respective rinks (p <.05). Rink values were 104.2 +/- 59.3 x 10(3) PM(1).cm(-3) during prime usage, compared to outdoor values of 3.8 +/- 2.5 x 10(3) PM(1).cm(-3). Ice resurfacing increased PM(1).cm(-3) 4-fold (p <.05). No difference in PM(1) emissions between gasoline and propane powered resurfacing machines was identified. The rate of PM(1) dissipation after resurfacing was highly variable between rinks and probably dependent upon rink ventilation and resurfacing machine engine efficiency. Gas-powered edging increased PM(1).cm(-3) 18-fold and 158-fold versus pre-edging rink and outdoor values, respectively. We conclude that the primary source of airborne indoor rink PM(1) is internal combustion ice-resurfacing machines and that this poor air quality may be causal to the unique and high prevalence of airway dysfunction in ice arena athletes.

  19. Temporal Variability of the Bioaerosol Background at a Subway Station: Concentration Level, Size Distribution, and Diversity of Airborne Bacteria

    PubMed Central

    Dybwad, Marius; Skogan, Gunnar

    2014-01-01

    Naturally occurring bioaerosol environments may present a challenge to biological detection-identification-monitoring (BIODIM) systems aiming at rapid and reliable warning of bioterrorism incidents. One way to improve the operational performance of BIODIM systems is to increase our understanding of relevant bioaerosol backgrounds. Subway stations are enclosed public environments which may be regarded as potential bioterrorism targets. This study provides novel information concerning the temporal variability of the concentration level, size distribution, and diversity of airborne bacteria in a Norwegian subway station. Three different air samplers were used during a 72-h sampling campaign in February 2011. The results suggested that the airborne bacterial environment was stable between days and seasons, while the intraday variability was found to be substantial, although often following a consistent diurnal pattern. The bacterial levels ranged from not detected to 103 CFU m−3 and generally showed increased levels during the daytime compared to the nighttime levels, as well as during rush hours compared to non-rush hours. The airborne bacterial levels showed rapid temporal variation (up to 270-fold) on some occasions, both consistent and inconsistent with the diurnal profile. Airborne bacterium-containing particles were distributed between different sizes for particles of >1.1 μm, although ∼50% were between 1.1 and 3.3 μm. Anthropogenic activities (mainly passengers) were demonstrated as major sources of airborne bacteria and predominantly contributed 1.1- to 3.3-μm bacterium-containing particles. Our findings contribute to the development of realistic testing and evaluation schemes for BIODIM equipment by providing information that may be used to simulate operational bioaerosol backgrounds during controlled aerosol chamber-based challenge tests with biological threat agents. PMID:24162566

  20. Investigating the spatial distribution of water levels in the Mackenzie Delta using airborne LiDAR

    USGS Publications Warehouse

    Hopkinson, C.; Crasto, N.; Marsh, P.; Forbes, D.; Lesack, L.

    2011-01-01

    Airborne light detection and ranging (LiDAR) data were used to map water level (WL) and hydraulic gradients (??H/??x) in the Mackenzie Delta. The LiDAR WL data were validated against eight independent hydrometric gauge measurements and demonstrated mean offsets from - 0??22 to + 0??04 m (??< 0??11). LiDAR-based WL gradients could be estimated with confidence over channel lengths exceeding 5-10 km where the WL change exceeded local noise levels in the LiDAR data. For the entire Delta, the LiDAR sample coverage indicated a rate of change in longitudinal gradient (??2H/??x) of 5??5 ?? 10-10 m m-2; therefore offering a potential means to estimate average flood stage hydraulic gradient for areas of the Delta not sampled or monitored. In the Outer Delta, within-channel and terrain gradient measurements all returned a consistent estimate of - 1 ?? 10-5 m m-1, suggesting that this is a typical hydraulic gradient for the downstream end of the Delta. For short reaches (<10 km) of the Peel and Middle Channels in the middle of the Delta, significant and consistent hydraulic gradient estimates of - 5 ?? 10-5 m m-1 were observed. Evidence that hydraulic gradients can vary over short distances, however, was observed in the Peel Channel immediately upstream of Aklavik. A positive elevation anomaly (bulge) of > 0??1 m was observed at a channel constriction entering a meander bend, suggesting a localized modification of the channel hydraulics. Furthermore, water levels in the anabranch channels of the Peel River were almost 1 m higher than in Middle Channel of the Mackenzie River. This suggests: (i) the channels are elevated and have shallower bank heights in this part of the delta, leading to increased cross-delta and along-channel hydraulic gradients; and/or (ii) a proportion of the Peel River flow is lost to Middle Channel due to drainage across the delta through anastamosing channels. This study has demonstrated that airborne LiDAR data contain valuable information describing

  1. Chromosome aberrations in lymphocytes of mice after sub-acute low-level inhalation exposure to benzene.

    PubMed

    Au, W W; Ramanujam, V M; Ward, J B; Legator, M S

    1991-06-01

    Male and female CD-1 mice were exposed to near ambient air concentrations of benzene by inhalation for 22 h per day, 7 days per week for 6 weeks. The concentrations were 0, 40, 100 and 1000 ppb. Significant increases in chromosome aberrations in spleen lymphocytes were observed in exposed compared with control mice except in the high-dose group (p less than 0.05 for female mice in 2 experiments and for male mice in 1 experiment; p less than 0.15 for male mice in the second experiment). A lack of increase in aberrations among mice of the high-dose group may be due to an induction of detoxifying enzymes as observed by us in a previous study (Au et al., 1988b). We also found that the female mice were more sensitive to the clastogenic activity of benzene than male mice under our experimental conditions. Our study serves to emphasize the need to conduct subchronic, low-dose in vivo genotoxicity studies using exposure conditions similar to those of humans, for evaluation of potential hazards. Our data suggest that the current occupational exposure concentrations for benzene (less than 1000 ppb) may still be hazardous to humans.

  2. Exposure vs toxicity levels of airborne quartz, metal and carbon particles in cast iron foundries.

    PubMed

    Moroni, Beatrice; Viti, Cecilia; Cappelletti, David

    2014-01-01

    Aerosol dust samples and quartz raw materials from different working stations in foundry plants were characterized in order to assess the health risk in this working environment. Samples were analysed by scanning and transmission electron microscopy coupled with image analysis and microanalysis, and by cathodoluminescence spectroscopy. In addition, the concentration and the solubility degree of Fe and other metals of potential health effect (Mn, Zn and Pb) in the bulk samples were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). Overall, the results indicate substantial changes in quartz crystal structure and texture when passing from the raw material to the airborne dust, which include lattice defects, non-bridging oxygen hole centres and contamination of quartz grains by metal and/or graphite particles. All these aspects point towards the relevance of surface properties on reactivity. Exposure doses have been estimated based on surface area, and compared with threshold levels resulting from toxicology. The possible synergistic effects of concomitant exposure to inhalable magnetite, quartz and/or graphite particles in the same working environment have been properly remarked. PMID:23385294

  3. Exposure vs toxicity levels of airborne quartz, metal and carbon particles in cast iron foundries.

    PubMed

    Moroni, Beatrice; Viti, Cecilia; Cappelletti, David

    2014-01-01

    Aerosol dust samples and quartz raw materials from different working stations in foundry plants were characterized in order to assess the health risk in this working environment. Samples were analysed by scanning and transmission electron microscopy coupled with image analysis and microanalysis, and by cathodoluminescence spectroscopy. In addition, the concentration and the solubility degree of Fe and other metals of potential health effect (Mn, Zn and Pb) in the bulk samples were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). Overall, the results indicate substantial changes in quartz crystal structure and texture when passing from the raw material to the airborne dust, which include lattice defects, non-bridging oxygen hole centres and contamination of quartz grains by metal and/or graphite particles. All these aspects point towards the relevance of surface properties on reactivity. Exposure doses have been estimated based on surface area, and compared with threshold levels resulting from toxicology. The possible synergistic effects of concomitant exposure to inhalable magnetite, quartz and/or graphite particles in the same working environment have been properly remarked.

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

    PubMed Central

    Neghab, Masoud; Hosseinzadeh, Kiamars; Hassanzadeh, Jafar

    2015-01-01

    Background Unleaded petrol contains significant amounts of monocyclic aromatic hydrocarbons such as benzene, toluene, and xylenes (BTX). Toxic responses following occupational exposure to unleaded petrol have been evaluated only in limited studies. The main purpose of this study was to ascertain whether (or not) exposure to unleaded petrol, under normal working conditions, is associated with any hepatotoxic or nephrotoxic response. Methods This was a cross-sectional study in which 200 employees of Shiraz petrol stations with current exposure to unleaded petrol, as well as 200 unexposed employees, were investigated. Atmospheric concentrations of BTX were measured using standard methods. Additionally, urine and fasting blood samples were taken from individuals for urinalysis and routine biochemical tests of kidney and liver function. Results The geometric means of airborne concentrations of BTX were found to be 0.8 mg m−3, 1.4 mg m−3, and 2.8 mg m−3, respectively. Additionally, means of direct bilirubin, alanine aminotransferase, aspartate aminotransferase, blood urea and plasma creatinine were significantly higher in exposed individuals than in unexposed employees. Conversely, serum albumin, total protein, and serum concentrations of calcium and sodium were significantly lower in petrol station workers than in their unexposed counterparts. Conclusion The average exposure of petrol station workers to BTX did not exceed the current threshold limit values (TLVs) for these chemicals. However, evidence of subtle, subclinical and prepathologic early liver and kidney dysfunction was evident in exposed individuals. PMID:26929843

  5. Seasonal variation in airborne endotoxin levels in indoor environments with different micro-environmental factors in Seoul, South Korea.

    PubMed

    Hwang, Sung Ho; Park, Dong Jin; Park, Wha Me; Park, Dong Uk; Ahn, Jae Kyoung; Yoon, Chung Sik

    2016-02-01

    This study evaluated the variation over a year in airborne endotoxin levels in the indoor environment of five university laboratories in Seoul, South Korea, and examined the micro-environmental factors that influenced endotoxin levels. These included temperature, relative humidity, CO2, CO, illumination, and wind velocity. A total of 174 air samples were collected and analyzed using the kinetic limulus amebocyte lysate assay. Endotoxin levels ranged from <0.001 to 8.90EU/m(3), with an overall geometric mean of 0.240EU/m(3). Endotoxin levels showed significantly negative correlation with temperature (r=-0.529, p<0.001), CO2 (r=-0.213, p<0.001) and illumination (r=-0.538, p<0.001). Endotoxin levels tended to be higher in winter. Endotoxin levels in laboratories with rabbits were significantly higher than those of laboratories with mice. Multivariate regression analysis showed that the environmental factors affecting endotoxin levels were temperature (coefficient=-0.388, p<0.001) and illumination (coefficient=-0.370, p<0.001). Strategies aimed at reducing airborne endotoxin levels in the indoor environments may be most effective if they focus on illumination. PMID:26656510

  6. Seasonal variation in airborne endotoxin levels in indoor environments with different micro-environmental factors in Seoul, South Korea.

    PubMed

    Hwang, Sung Ho; Park, Dong Jin; Park, Wha Me; Park, Dong Uk; Ahn, Jae Kyoung; Yoon, Chung Sik

    2016-02-01

    This study evaluated the variation over a year in airborne endotoxin levels in the indoor environment of five university laboratories in Seoul, South Korea, and examined the micro-environmental factors that influenced endotoxin levels. These included temperature, relative humidity, CO2, CO, illumination, and wind velocity. A total of 174 air samples were collected and analyzed using the kinetic limulus amebocyte lysate assay. Endotoxin levels ranged from <0.001 to 8.90EU/m(3), with an overall geometric mean of 0.240EU/m(3). Endotoxin levels showed significantly negative correlation with temperature (r=-0.529, p<0.001), CO2 (r=-0.213, p<0.001) and illumination (r=-0.538, p<0.001). Endotoxin levels tended to be higher in winter. Endotoxin levels in laboratories with rabbits were significantly higher than those of laboratories with mice. Multivariate regression analysis showed that the environmental factors affecting endotoxin levels were temperature (coefficient=-0.388, p<0.001) and illumination (coefficient=-0.370, p<0.001). Strategies aimed at reducing airborne endotoxin levels in the indoor environments may be most effective if they focus on illumination.

  7. Benzene pollution from gasoline usage.

    PubMed

    Foo, S C

    1991-04-01

    Local gasolines contain benzene ranging from 1.8 to 3.7% and their use can lead to significant exposure to benzene. Gasoline station attendants were found to be exposed to short-term exposure levels (STEL) of 0.064-179 ppm. Their 8-h time-weighted averaged (TWA) exposure ranged from 0.028 to 0.71 ppm. For motorcar service mechanics, TWA exposure levels ranged from 0.014 to 1.7 ppm. The exposure of drivers of gasoline delivery tankers ranged from 0.08 to 2.37 ppm for personal TWA exposure over the whole workshift. For local people not occupationally exposed to gasoline or other benzene-containing volatile chemicals, exposure from the ambient environment ranged from 0.0023 to 0.027 ppm. Gasoline usage also contributed to the contamination of surface water with benzene. Benzene levels in water samples taken from drains leading from gasoline stations were between 1.1 and 40.4 micrograms l-1.

  8. Correlation between airborne Olea europaea pollen concentrations and levels of the major allergen Ole e 1 in Córdoba, Spain, 2012-2014

    NASA Astrophysics Data System (ADS)

    Plaza, M. P.; Alcázar, P.; Galán, C.

    2016-04-01

    Olea europaea L. pollen is the second-largest cause of pollinosis in the southern Iberian Peninsula. Airborne-pollen monitoring networks provide essential data on pollen dynamics over a given study area. Recent research, however, has shown that airborne pollen levels alone do not always provide a clear indicator of actual exposure to aeroallergens. This study sought to evaluate correlations between airborne concentrations of olive pollen and Ole e 1 allergen levels in Córdoba (southern Spain), in order to determine whether atmospheric pollen concentrations alone are sufficient to chart changes in hay fever symptoms. The influence of major weather-related variables on local airborne pollen and allergen levels was also examined. Monitoring was carried out from 2012 to 2014. Pollen sampling was performed using a Hirst-type sampler, following the protocol recommended by the Spanish Aerobiology Network. A multi-vial cyclone sampler was used to collect aeroallergens, and allergenic particles were quantified by ELISA assay. Significant positive correlations were found between daily airborne allergen levels and atmospheric pollen concentrations, although there were occasions when allergen was detected before and after the pollen season and in the absence of airborne pollen. The correlation between the two was irregular, and pollen potency displayed year-on-year variations and did not necessarily match pollen-season-intensity.

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

    PubMed

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

    1990-05-01

    Metabolism of benzene is thought to be necessary to produce the toxic effects, including carcinogenicity, associated with benzene exposure. To extrapolate from the results of rodent studies to potential health risks in man, one must know how benzene metabolism is affected by species, dose, dose rate, and repeated versus single exposures. The purpose of our studies was to determine the effect of repeated inhalation exposures on the metabolism of [14C]benzene by rodents. Benzene metabolism was assessed by characterizing and quantitating urinary metabolites, and by quantitating 14C bound to hemoglobin and micronuclei induction. F344/N rats and B6C3F1 mice were exposed, nose-only, to 600 ppm benzene or to air (control) for 6 hr/day, 5 days/week for 3 weeks. On the last day, both benzene-pretreated and control animals were exposed to 600 ppm, 14C-labeled benzene for 6 hr. Individual benzene metabolites in urine collected for 24 hr after the exposure were analyzed. There was a significant decrease in the respiratory rate of mice (but not rats) pretreated with benzene which resulted in lower levels of urinary [14C]benzene metabolites. The analyses indicated that the only effects of benzene pretreatment on the metabolite profile in rat or mouse urine were a slight shift from glucuronidation to sulfation in mice and a shift from sulfation to glucuronidation in rats. Benzene pretreatment also had no effect, in either species, on formation of [14C]benzene-derived hemoglobin adducts. Mice and rats had similar levels of hemoglobin adduct binding, despite the higher metabolism of benzene by mice. This indicates that hemoglobin adduct formation occurs with higher efficiency in rats. After 1 week of exposure to 600 ppm benzene, the frequency of micronucleated, polychromatic erythrocytes (PCEs) in mice was significantly increased. Exposure to the same level of benzene for an additional 2 weeks did not further increase the frequency of micronuclei in PCEs. These results indicate

  10. Use of the selective agar medium CREAD for monitoring the level of airborne spoilage moulds in cheese production.

    PubMed

    Kure, Cathrine Finne; Borch, Elisabeth; Karlsson, Ingela; Homleid, Jens Petter; Langsrud, Solveig

    2008-02-29

    It was investigated if a selective medium for common cheese spoiling moulds (CREAD) could give more relevant information than a general mould medium in hygienic air-sampling in cheese factories. A total of 126 air-samples were taken in six Nordic cheese factories using the general mould medium DG18 and CREAD. The level and genera of air-borne mould was determined. Identification to species-level was performed for a selection of samples. In five cheese factories the mycobiota was dominated by Penicillium spp. and in one cheese factory by Cladosporium spp. The concentration of air-borne moulds varied between the cheese factories ranging from 1 to 270 cfu/m3 on DG18 with a median value of 17. The number of mould colonies was in general lower at CREAD. Identification indicated that CREAD supported growth of common spoilage moulds for cheese, such as Penicillium palitans and P. commune. The mycobiota on DG18 also consisted of moulds not commonly associated with spoilage of cheese, such as Cladosporium spp., P. brevicompactum and P. chrysogenum. Contamination of cheese with mould is periodically a problem in production of semi-hard cheese and the level of air-borne mould is therefore routinely monitored in cheese factories. A clear correlation between the total number of moulds in air and mould growth on products is not always found. The conclusion from the investigation is that it is recommended to use a selective medium for cheese spoilage moulds, such as CREAD in hygienic monitoring.

  11. Environmental releases from fuel cycle facility: part 1: radionuclide resuspension vs. stack releases on ambient airborne uranium and thorium levels.

    PubMed

    Masson, Olivier; Pourcelot, Laurent; Boulet, Béatrice; Cagnat, Xavier; Videau, Gérard

    2015-03-01

    Airborne activity levels of uranium and thorium series were measured in the vicinity (1.1 km) of a uranium (UF4) processing plant, located in Malvési, south of France. Regarding its impact on the environment, this facility is characterized by its routine atmospheric releases of uranium and by the emission of radionuclide-labelled particles from a storage pond filled with waste water or that contain dried sludge characterized by traces of plutonium and thorium ((230)Th). This study was performed during a whole year (November 2009-November 2010) and based on weekly aerosol sampling. Thanks to ICP-MS results, it was possible to perform investigations of uranium and thorium decay product concentration in the air. The number of aerosol filters sampled (50) was sufficient to establish a relationship between airborne radionuclide variations and the wind conditions. As expected, the more the time spent in the plume, the higher the ambient levels. The respective contributions of atmospheric releases and resuspension from local soil and waste ponds on ambient dust load and uranium-bearing aerosols were estimated. Two shutdown periods dedicated to facility servicing made it possible to estimate the resuspension contribution and to specify its origin (local or regional) according to the wind direction and remote background concentration. Airborne uranium mainly comes from the emission stack and, to a minor extent (∼20%), from wind resuspension of soil particles from the surrounding fields and areas devoted to waste storage. Moreover, weighed activity levels were clearly higher during operational periods than for shutdown periods.

  12. Environmental releases from fuel cycle facility: part 1: radionuclide resuspension vs. stack releases on ambient airborne uranium and thorium levels.

    PubMed

    Masson, Olivier; Pourcelot, Laurent; Boulet, Béatrice; Cagnat, Xavier; Videau, Gérard

    2015-03-01

    Airborne activity levels of uranium and thorium series were measured in the vicinity (1.1 km) of a uranium (UF4) processing plant, located in Malvési, south of France. Regarding its impact on the environment, this facility is characterized by its routine atmospheric releases of uranium and by the emission of radionuclide-labelled particles from a storage pond filled with waste water or that contain dried sludge characterized by traces of plutonium and thorium ((230)Th). This study was performed during a whole year (November 2009-November 2010) and based on weekly aerosol sampling. Thanks to ICP-MS results, it was possible to perform investigations of uranium and thorium decay product concentration in the air. The number of aerosol filters sampled (50) was sufficient to establish a relationship between airborne radionuclide variations and the wind conditions. As expected, the more the time spent in the plume, the higher the ambient levels. The respective contributions of atmospheric releases and resuspension from local soil and waste ponds on ambient dust load and uranium-bearing aerosols were estimated. Two shutdown periods dedicated to facility servicing made it possible to estimate the resuspension contribution and to specify its origin (local or regional) according to the wind direction and remote background concentration. Airborne uranium mainly comes from the emission stack and, to a minor extent (∼20%), from wind resuspension of soil particles from the surrounding fields and areas devoted to waste storage. Moreover, weighed activity levels were clearly higher during operational periods than for shutdown periods. PMID:25613358

  13. Carcinogenic effects of benzene: Cesare Maltoni's contributions.

    PubMed

    Mehlman, Myron A

    2002-12-01

    Cesare Maltoni's contributions to understanding, identifying, and characterizing widely used commercial chemicals in experimental animals are among the most important methods developed in the history of toxicology and serve to protect working men and women, the general population, and our environment from hazardous substances. Maltoni developed experimental methods that have reached the "platinum standard" for protection of public health. Benzene was among the 400 or more chemicals that Maltoni and his associates tested for carcinogenicity. In 1976, Maltoni reported that benzene is a potent experimental carcinogen. Maltoni's experiments clearly demonstrated that benzene is carcinogenic in Sprague-Dawley rats, Wistar rats, Swiss mice, and RF/J mice when administered by inhalation or ingestion. Benzene caused carcinomas of the Zymbal gland, oral cavity, nasal cavities; cancers of the skin, forestomach, mammary glands, and lungs; angiosarcomas and hepatomas of the liver; and hemolymphoreticular cancers. Thus, benzene was shown to be a multipotential carcinogen that produced cancers in several species of animals by various routes of administration. On November 2, 1977, Chemical Week reported that Maltoni provided a "bombshell" when he demonstrated the "first direct link" between benzene and cancer. In this paper, I shall summarize early experiments and human studies and reports; Maltoni's experimental contribution to understanding the carcinogenicity of benzene in humans and animals; earlier knowledge concerning benzene toxicity; and benzene standards and permissible exposure levels.

  14. Asbestos-containing materials and airborne asbestos levels in industrial buildings in Korea.

    PubMed

    Choi, Sangjun; Suk, Mee-Hee; Paik, Nam Won

    2010-03-01

    Recently in Korea, the treatment of asbestos-containing materials (ACM) in building has emerged as one of the most important environmental health issues. This study was conducted to identify the distribution and characteristics of ACM and airborne asbestos concentrations in industrial buildings in Korea. A total of 1285 presumed asbestos-containing material (PACM) samples were collected from 80 workplaces across the nation, and 40% of the PACMs contained more than 1% of asbestos. Overall, 94% of the surveyed workplaces contained ACM. The distribution of ACM did not show a significant difference by region, employment size, or industry. The total ACM area in the buildings surveyed was 436,710 m2. Ceiling tile ACM accounted for 61% (267,093 m2) of the total ACM area, followed by roof ACM (32%), surfacing ACM (6.1%), and thermal system insulation (TSI). In terms of asbestos type, 98% of total ACM was chrysotile, while crocidolite was not detected. A comparison of building material types showed that the material with the highest priority for regular management is ceiling tile, followed by roof, TSI, and surfacing material. The average airborne concentration of asbestos sampled without disturbing in-place ACM was 0.0028 fibers/cc by PCM, with all measurements below the standard of recommendation for indoor air quality in Korea (0.01 fibers/cc).

  15. Airborne and surface-level in situ observations of wintertime clouds in the Southern Rockies

    NASA Astrophysics Data System (ADS)

    Dorsi, Samuel Winchester

    The phase of cloud water has important impacts on cloud radiative properties, cloud lifetime, and the formation of precipitation. Mixed-phase clouds, or those in which liquid droplets, ice particle and water vapor co-exist, are of particular importance in the Southern Rockies of the United States, where these clouds enhance wintertime mountain precipitation mass and annual water storage in the snowpack. The interaction between multiple water phases within a cloud presents challenges for in situ observation. I describe the existing in situ cloud microphysical instrumentation, and introduce a new instrument for the in situ measurement of total water concentration: the second-generation University of Colorado closed-path tunable-diode laser hygrometer (CLH-2). This compact instrument can be flown within a scientific aircraft under-wing canister and is designed for operation in diverse environmental conditions. During the winter 2010-2011, the CLH-2 was installed on a wind vane at Storm Peak Laboratory (SPL) in the Park Range of Colorado as a part of the Storm Peak Laboratory Cloud Property Validation Experiment (StormVEx) campaign. I apply a new method for determining the bulk mass-dimensional relationship of ice particles from ground-based observations. Despite important difference between airborne and ground-based particle measurements, my parameterization yields particle masses close to those from recent airborne studies that take into account the effect of ice particle shattering on observed number concentrations. Variations in particle density over the course of a storm are suggested by time variations between the observed and parameterized ice water concentrations. Using observations from the Wyoming King Air research aircraft collected during the Colorado Airborne Multi-Phase Cloud Study (CAMPS) in winter 2010-2011, cloud water phase is identified using in situ microphysical measurements. While mixed-phase clouds are identified throughout the study area, the

  16. Application of infrared radiometers for airborne detection of clear air turbulence and low level wind shear, airborne infrared low level wind shear detection test

    NASA Technical Reports Server (NTRS)

    Kuhn, P. M.

    1985-01-01

    The feasibility of infrared optical techniques for the advance detection and avoidance of low level wind shear (LLWS) or low altitude wind shear hazardous to aircraft operations was investigated. A primary feasibility research effort was conducted with infrared detectors and instrumentation aboard the NASA Ames Research Center Learjet. The main field effort was flown on the NASA-Ames Dryden B57B aircraft. The original approach visualized a forward-looking, infrared transmitting (KRS-5) window through which signals would reach the detector. The present concept of a one inch diameter light pipe with a 45 deg angled mirror enables a much simpler installation virtually anywhere on the aircraft coupled with the possibility of horizontal scanning via rotation of the forward directed mirror. Present infrared detectors and filters would certainly permit ranging and horizontal scanning in a variety of methods. CRT display technology could provide a contoured picture with possible shear intensity levels from the infrared detection system on the weather radar or a small adjunct display. This procedure shoud be further developed and pilot evaluated in a light aircraft such as a Cessna 207 or equivalent.

  17. Airborne Soil Moisture determination at regional level: A data fusion mission approach for Catalan territory

    NASA Astrophysics Data System (ADS)

    Martin, Francisco; Corbera, Jordi; Marchan, Juan Fernando; Camps, Adriano

    2010-05-01

    During the last years the importance of water management has grown considerably. Average temperatures exhibit an increasing pattern (0.77 °C during the last 20 years) that is expected to continue in the next years. These results in a decrease in the hydrical resources (15% during the last 20 years for the Catalan territori) being the expectative not very optimist. A tangible consequence was the drought episode that suffers Catalonia. It is within this scenario that the ‘Programa Català d'Observació de la Terra' (PCOT) as a unit of the official mapping agency of Catalonia, the ‘Institut Cartogràfic de Catalunya' (ICC) has detected the need to develop new tools to improve the management of water resources. The knowledge of soil moisture across a given region can help to efficiently manage the limited water resources. Present Earth Observations missions such as ESA's SMOS, or the future NASA's SMAP focus considerably their efforts in the estimation of soil moisture. The main drawbacks are the resolutions obtained (40 km for SMOS, 10 km for SMAP), which are not adequate for regional scale and territorial availability such as the case of Catalonia where a spatial resolution in a range between 20-30m. and 100-150m. is desired both for local actuations and to deteminate hidric soil patterns In this scenario, PCOT is carrying out an airborne soil moisture mission for the Catalan territory, taking advantage of the availability of ICC aircrafts and of more than 20 years of experience in making aircraft campaigns and operating hyperspectral airborne sensors such as CASI (0.75-1.4 µm) and TASI (8-11.5 µm) to respond to environmental and cartographic end users needs of geoinformation data, products and services. This mission will generate soil moisture maps over the Catalan region that will improve the water management, and will also be used for the study of the hydrological patterns of Catalonia. Soil moisture determination will be achieved by means of L

  18. Levels and spatial distribution of airborne chemical elements in a heavy industrial area located in the north of Spain.

    PubMed

    Lage, J; Almeida, S M; Reis, M A; Chaves, P C; Ribeiro, T; Garcia, S; Faria, J P; Fernández, B G; Wolterbeek, H T

    2014-01-01

    The adverse health effects of airborne particles have been subjected to intense investigation in recent years; however, more studies on the chemical characterization of particles from pollution emissions are needed to (1) identify emission sources, (2) better understand the relative toxicity of particles, and (3) pinpoint more targeted emission control strategies and regulations. The main objective of this study was to assess the levels and spatial distribution of airborne chemical elements in a heavy industrial area located in the north of Spain. Instrumental and biomonitoring techniques were integrated and analytical methods for k0 instrumental neutron activation analysis and particle-induced x-ray emission were used to determine element content in aerosol filters and lichens. Results indicated that in general local industry contributed to the emissions of As, Sb, Cu, V, and Ni, which are associated with combustion processes. In addition, the steelwork emitted significant quantities of Fe and Mn and the cement factory was associated with Ca emissions. The spatial distribution of Zn and Al also indicated an important contribution of two industries located outside the studied area. PMID:25072718

  19. Biochemical toxicity of benzene.

    PubMed

    Rana, S V S; Verma, Yeshvandra

    2005-04-01

    Human exposure to benzene in work environment is a global occupational health problem. After inhalation or absorption, benzene targets organs viz. liver, kidney, lung, heart and brain etc. It is metabolized mainly in the liver by cytochrome P450 multifunctional oxygenase system. Benzene causes haematotoxicity through its phenolic metabolites that act in concert to produce DNA strand breaks, chromosomal damage, sister chromatid exchange, inhibition of topoisomerase II and damage to mitotic spindle. The carcinogenic and myelotoxic effects of benzene are associated with free radical formation either as benzene metabolites or lipid peroxidation products. Benzene oxide and phenol have been considered as proheptons. Liver microsomes play an important role in biotransformation of benzene whereas in kidney, it produces degenerative intracellular changes. Cohort studies made in different countries suggest that benzene induces multiple myeloma in petrochemical workers. Though extensive studies have been performed on its toxicity, endocrinal disruption caused by benzene remains poorly known. Transgenic cytochrome P450 IIE1 mice may help in understanding further toxic manifestations of benzene.

  20. Systems biology of human benzene exposure

    PubMed Central

    Zhang, Luoping; McHale, Cliona M.; Rothman, Nathaniel; Li, Guilan; Ji, Zhiying; Vermeulen, Roel; Hubbard, Alan E.; Ren, Xuefeng; Shen, Min; Rappaport, Stephen M.; North, Matthew; Skibola, Christine F.; Yin, Songnian; Vulpe, Christopher; Chanock, Stephen J.; Smith, Martyn T.; Lan, Qing

    2010-01-01

    Toxicogenomic studies, including genome-wide analyses of susceptibility genes (genomics), gene expression (transcriptomics), protein expression (proteomics), and epigenetic modifications (epigenomics), of human populations exposed to benzene are crucial to understanding gene-environment interactions, providing the ability to develop biomarkers of exposure, early effect and susceptibility. Comprehensive analysis of these toxicogenomic and epigenomic profiles by bioinformatics in the context of phenotypic endpoints, comprises systems biology, which has the potential to comprehensively define the mechanisms by which benzene causes leukemia. We have applied this approach to a molecular epidemiology study of workers exposed to benzene. Hematotoxicity, a significant decrease in almost all blood cell counts, was identified as a phenotypic effect of benzene that occurred even below 1ppm benzene exposure. We found a significant decrease in the formation of progenitor colonies arising from bone marrow stem cells with increasing benzene exposure, showing that progenitor cells are more sensitive to the effects of benzene than mature blood cells, likely leading to the observed hematotoxicity. Analysis of transcriptomics by microarray in the peripheral blood mononuclear cells of exposed workers, identified genes and pathways (apoptosis, immune response, and inflammatory response) altered at high (>10ppm) and low (<1ppm) benzene levels. Serum proteomics by SELDI-TOF-MS revealed proteins consistently down-regulated in exposed workers. Preliminary epigenomics data showed effects of benzene on the DNA methylation of specific genes. Genomic screens for candidate genes involved in susceptibility to benzene toxicity are being undertaken in yeast, with subsequent confirmation by RNAi in human cells, to expand upon the findings from candidate gene analyses. Data on these and future biomarkers will be used to populate a large toxicogenomics database, to which we will apply bioinformatic

  1. A brief report of gram-negative bacterial endotoxin levels in airborne and settled dusts in animal confinement buildings

    SciTech Connect

    Thedell, T.D.; Mull, J.C.; Olenchock, S.A.

    1980-01-01

    Gram-negative bacterial endotoxins, implicated in adverse worker health responses, were found in settled and airborne dust samples obtained from poultry and swine confinement units. Results of the Limulus amebocyte lysate gel test found endotoxin levels in dust samples ranged from 4.5 to 47.7 micrograms of FDA Klebsiella endotoxin equivalents/gm. Differences in endotoxin levels between dust samples may have been due to variables in time, geographic locations, confined animals, confinement buildings and equipment, and methods of sample collection. Animal confinement workers are potentially exposed to large amounts of gram-negative bacterial endotoxins; however, the respiratory health effects of such exposures to animal confinement workers have yet to be determined.

  2. Prevalence and airborne spore levels of Stachybotrys spp. in 200 houses with water incursions in Houston, Texas.

    PubMed

    Kuhn, Ryan C; Trimble, Mingyi W; Hofer, Vasanthi; Lee, Michael; Nassof, Russell S

    2005-01-01

    Two hundred homes with a history of water incursion were sampled for fungi to determine the prevalence and airborne spore levels of Stachybotrys spp. Sampling methods included room air, surface, and wall cavity air sampling. Stachybotrys spp. were detected with at least one of the methods in 58.5% of the houses tested, but only 9.6% of the room air samples contained Stachybotrys spores. Aerosolization of Stachybotrys spores was correlated with both wall cavity and surface contamination. However, after adjustment for the surface effect, Stachybotrys spores detected in wall cavities were not a significant factor contributing to spores detected in room air samples. We conclude that Stachybotrys spp. are commonly found on water-damaged building materials. In addition, the observations made in this study suggest that the impact on the living space air is low if the fungal spores are contained within a wall cavity.

  3. Solutions for extracting file level spatial metadata from airborne mission data

    NASA Astrophysics Data System (ADS)

    Schwab, M. J.; Stanley, M.; Pals, J.; Brodzik, M.; Fowler, C.; Icebridge Engineering/Spatial Metadata

    2011-12-01

    Authors: Michael Stanley Mark Schwab Jon Pals Mary J. Brodzik Cathy Fowler Collaboration: Raytheon EED and NSIDC Raytheon / EED 5700 Rivertech Court Riverdale, MD 20737 NSIDC University of Colorado UCB 449 Boulder, CO 80309-0449 Data sets acquired from satellites and aircraft may differ in many ways. We will focus on the differences in spatial coverage between the two platforms. Satellite data sets over a given period typically cover large geographic regions. These data are collected in a consistent, predictable and well understood manner due to the uniformity of satellite orbits. Since satellite data collection paths are typically smooth and uniform the data from satellite instruments can usually be described with simple spatial metadata. Subsequently, these spatial metadata can be stored and searched easily and efficiently. Conversely, aircraft have significantly more freedom to change paths, circle, overlap, and vary altitude all of which add complexity to the spatial metadata. Aircraft are also subject to wind and other elements that result in even more complicated and unpredictable spatial coverage areas. This unpredictability and complexity makes it more difficult to extract usable spatial metadata from data sets collected on aircraft missions. It is not feasible to use all of the location data from aircraft mission data sets for use as spatial metadata. The number of data points in typical data sets poses serious performance problems for spatial searching. In order to provide efficient spatial searching of the large number of files cataloged in our systems, we need to extract approximate spatial descriptions as geo-polygons from a small number of vertices (fewer than two hundred). We present some of the challenges and solutions for creating airborne mission-derived spatial metadata. We are implementing these methods to create the spatial metadata for insertion of IceBridge mission data into ECS for public access through NSIDC and ECHO but, they are

  4. Seagrass biomass and productivity in the Florida Keys, USA: ground-level and airborne measurements

    NASA Astrophysics Data System (ADS)

    Yarbro, L.; Carlson, P. R., Jr.; McHan, C.; Carlson, D. F.; Hu, C.; Danielson, T.; Durnan, B.; English, D. C.; Muller-Karger, F. E.; Yates, K. K.; Herwitz, S.; Merrill, J.; Mewes, T.

    2013-12-01

    Seagrass communities serve as essential habitat for fish and shellfish, and recent research indicates that they can play a significant role in reducing ocean acidification. As part of a collaborative project funded by the NASA ROSES program and administered by the NASA UAV Collaborative, we collected hyperspectral imagery of seagrass beds and measured productivity of Thalassia testudinum at Sugarloaf Key, Florida, in May 2012, October 2012, and May 2013. Our primary goal was to evaluate the utility of hyperspectral sensors, in general, and UAV platforms, in specific, to measure seagrass health and productivity. Airborne measurements using the AISA Eagle hyperspectral imaging system were carried out simultaneously with ground measurements of Thalassia fluorescence, oxygen metabolism, growth, and biomass, as well as remote sensing reflectance and several in situ optical properties. Water depths at the study site ranged from less than 1 m to 5 m. Phytoplankton chlorophyll-a concentrations (0.09-0.72 ug l-1), ag(440) (0-0.02 m-1), and turbidity (0.12-4.1 ntu) were relatively low for all three deployments, facilitating the collection of excellent imagery and application of water-column radiative-transfer corrections. Aboveground Thalassia and macroalgal biomass, at 18 sites in the study area, ranged from 210 to 690 and 11 to 590 gDW m-2, respectively. One-sided green leaf area index of Thalassia ranged from 0.7 to 3.0. Preliminary findings show that the sensitivity of relationships between seagrass productivity and biomass parameters and remotely-sensed habitat spectra is reduced with increasing water depth and, even in shallow water, is complicated by epiphytic algae and sediment coverage of leaf surfaces.

  5. Tropical forest structure characterization using airborne lidar data: an individual tree level approach

    NASA Astrophysics Data System (ADS)

    Ferraz, A.; Saatchi, S. S.

    2015-12-01

    Fine scale tropical forest structure characterization has been performed by means of field measurements techniques that record both the specie and the diameter at the breast height (dbh) for every tree within a given area. Due to dense and complex vegetation, additional important ecological variables (e.g. the tree height and crown size) are usually not measured because they are hardly recognized from the ground. The poor knowledge on the 3D tropical forest structure has been a major limitation for the understanding of different ecological issues such as the spatial distribution of carbon stocks, regeneration and competition dynamics and light penetration gradient assessments. Airborne laser scanning (ALS) is an active remote sensing technique that provides georeferenced distance measurements between the aircraft and the surface. It provides an unstructured 3D point cloud that is a high-resolution model of the forest. This study presents the first approach for tropical forest characterization at a fine scale using remote sensing data. The multi-modal lidar point cloud is decomposed into 3D clusters that correspond to single trees by means of a technique called Adaptive Mean Shift Segmentation (AMS3D). The ability of the corresponding individual tree metrics (tree height, crown area and crown volume) for the estimation of above ground biomass (agb) over the 50 ha CTFS plot in Barro Colorado Island is here assessed. We conclude that our approach is able to map the agb spatial distribution with an error of nearly 12% (RMSE=28 Mg ha-1) compared with field-based estimates over 1ha plots.

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

    PubMed

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

    2016-03-01

    DNA damage and cellular repair capacity were studied in 18 male fuel tanker drivers and 13 male filling-station attendants exposed to low and very low concentrations of benzene, respectively, and compared to 20 males with no occupational exposure (controls). Exposure to airborne benzene was measured using passive personal samplers, and internal doses were assayed through the biomarkers t,t-muconic acid, S-phenylmercapturic acid and urinary benzene. DNA damage was evaluated using tail intensity (TI) determined by the comet assay in peripheral lymphocytes. Urinary 7-hydro-8-oxo-2'-deoxyguanosine (8-oxodG) was measured as a biomarker of oxidative damage. DNA repair kinetics were assessed using the comet assay in lymphocytes sampled 20 and 60 min post H2O2 exposure. Benzene exposure differed significantly between the drivers (median 246.3 µg/m(3)), attendants (median 13.8 µg/m(3)), and controls (median 4.1 µg/m(3)). There were no differences in TI and 8-oxodG among the three groups, or between smokers and non-smokers. DNA repair kinetics were similar among the drivers, attendants and controls, although the comet assay on H2 O2 -damaged lymphocytes after 60 min revealed significantly lower levels of TI only in drivers. The DNA repair process in smokers was similar to that observed in drivers. In conclusion, this study found no relationship between low levels of benzene exposure and DNA damage, although there was evidence that exposure interferes with DNA repair kinetics. The biological impact of this finding on the onset of genotoxic effects in exposed workers has still to be ascertained. PMID:26646167

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

    PubMed

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

    2016-03-01

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

  8. The toxicology of benzene.

    PubMed Central

    Snyder, R; Witz, G; Goldstein, B D

    1993-01-01

    Benzene is metabolized, primarily in the liver, to a series of phenolic and ring-opened products and their conjugates. The mechanism of benzene-induced aplastic anemia appears to involve the concerted action of several metabolites acting together on early stem and progenitor cells, as well as on early blast cells, such as pronormoblasts and normoblasts to inhibit maturation and amplification. Benzene metabolites also inhibit the function of microenvironmental stromal cells necessary to support the growth of differentiating and maturing marrow cells. The mechanism of benzene-induced leukemogenesis is less well understood. Benzene and its metabolites do not function well as mutagens but are highly clastogenic, producing chromosome aberrations, sister chromatid exchange, and micronuclei. Benzene has been shown to be a multi-organ carcinogen in animals. Epidemiological studies demonstrate that benzene is a human leukemogen. There is need to better define the lower end of the dose-response curve for benzene as a human leukemogen. The application of emerging methods in biologically based risk assessment employing pharmacokinetic and mechanistic data may help to clarify the uncertainties in low-dose risk assessment. PMID:8354177

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

    SciTech Connect

    Tan, C.; Ong, H.Y.; Kok, P.W.

    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.

  10. Domestic airborne black carbon levels and 8-isoprostane in exhaled breath condensate among children in New York City☆

    PubMed Central

    Rosa, Maria Jose; Yan, Beizhan; Chillrud, Steven N.; Acosta, Luis M.; Divjan, Adnan; Jacobson, Judith S.; Miller, Rachel L.; Goldstein, Inge F.; Perzanowski, Matthew S.

    2015-01-01

    Background Exposure to airborne black carbon (BC) has been associated with asthma development, respiratory symptoms and decrements in lung function. However, the mechanism through which BC may lead to respiratory symptoms has not been completely elucidated. Oxidative stress has been suggested as a potential mechanism through which BC might lead to adverse health outcomes. Exhaled breath condensate (EBC) allows for the non-invasive collection of airway lining fluid containing biomarkers of oxidative stress like 8-isoprostane, a stable by-product of lipid peroxidation. Therefore, we sought to characterize the association between domestic airborne BC concentrations and 8-isoprostane in EBC. Materials and methods Seven- and eight-year-old children participated in an asthma case–control study in New York City. During home visits, air samples and EBC were collected. Seven day averages of domestic levels of particulate matter <2.5 µm (PM2.5), BC and environmental tobacco smoke (ETS) were measured. Urea and 8-isoprostane were measured by liquid chromatography tandem mass spectrometry (LC/MS/MS) in EBC. Results In univariate models, PM2.5 and BC, but not ETS, were significantly associated with increases in 8-isoprostane in the EBC (β = 0.006 and β = 0.106 respectively, p < 0.05 for both). These associations remained statistically significant for both PM2.5 and BC after adjustment for covariates. In a co-pollutant model including PM2.5, BC and ETS, only BC remained a statistically significant predictor of 8-isoprostane (p < 0.05). Conclusions Our findings suggest the BC fraction of PM might contain exposure relevant to increased oxidative stress in the airways. PMID:25262082

  11. Delivery of benzene to Alcaligenes xylosoxidans by solid polymers in a two-phase partitioning bioreactor.

    PubMed

    Daugulis, Andrew J; Amsden, Brian G; Bochanysz, Justina; Kayssi, Ahmed

    2003-07-01

    Toxic levels of benzene were decreased to sub-inhibitory levels in a bioreactor via absorption by polymer beads or cylinders (poly(ethylene-co-vinyl acetate) or poly(styrene-co-butadiene)). After inoculation with Alcaligenes xylosoxidans, the remaining benzene in the aqueous phase as well as the benzene taken up by the polymers was degraded to completion. The capacity of these polymers for benzene, and benzene diffusivity within the polymers were also determined.

  12. The influence of coal physical and mechanical properties and mining energy consumption factor on airborne respirable dust level

    SciTech Connect

    Koziel, A.; Malec, M.; Wardas, E.

    1999-07-01

    The fact that there are not any explicitly defined relationships describing the influence of physical and mechanical properties of coal and of energy consumption factor on dust level prompted Polish and American investigators to carry out a joint research project within the framework of the US-Poland Maria Sklodowska-Curie Joint Fund II. The paper presents methods used to perform tests under laboratory conditions at the Pittsburgh Research Laboratory as well as under real conditions in the course of coal cutting in Polish coal mines. Measuring systems and results of the tests are described. The analysis carried out has provided a basis for determining the influence of specified operational parameters, i.e., coal compression strength R{sub c}, coal cuttability factor A, energy consumption factor of mining E{sub uc}, load of cutting drums as well as of laboratory parameters, i.e., grindability, coal breakage characteristics (product size distribution), moisture content, volatile and fixed carbon content, specific energy of crushing on a level of generated dust (total dust, specific dust and airborne respirable dust). The effect of technical parameters, i.e., face height, airflow velocity in a face, amount and pressure of water in spraying systems of longwall shearers, depth of cut taken by a cutting drum and application of powered cowls on dust level under operating conditions are also presented. Results of the tests made it possible to work out guidelines relating to methods and technology for effective reduction of dust emission on longwall faces.

  13. Endotoxin levels in settled airborne dust in European schools: the HITEA school study.

    PubMed

    Jacobs, J H; Krop, E J M; Borras-Santos, A; Zock, J-P; Taubel, M; Hyvarinnen, A; Pekkanen, J; Doekes, G; Heederik, D J J

    2014-04-01

    Indoor exposure to microbial agents is known to influence respiratory health. Besides home exposure, exposure in schools can affect respiratory health. In this study, we measured endotoxin in settled dust in primary schools in three European countries from three different geographical regions with different climates. Our aim was to characterize endotoxin levels in primary schools and evaluate associations with potential determinants. Endotoxin levels were repeatedly assessed in 23 schools in Spain (n = 7), the Netherlands (n = 10), and Finland (n = 6) using electrostatic dustfall collectors. In total, 645 measurements were taken in 237 classrooms. Endotoxin levels differed significantly between countries; Dutch schools had the highest levels, while Finnish schools showed the lowest levels. In each country, differences in endotoxin levels were observed between schools and over the sampling periods. Estimates improved after adjustment for sampling period. Factors affecting endotoxin levels in a school differed per country. In general, endotoxin levels were higher in lower grades and in classrooms with higher occupancy. School endotoxin levels may contribute significantly to total endotoxin exposure in children and teachers. As the correlation between the repeated measurements is reasonable, single endotoxin measurements form a reasonable basis for estimating annual endotoxin levels in schools.

  14. Refiners have several options for reducing gasoline benzene

    SciTech Connect

    Goelzer, A.R.; Hernandez-Robinson, A. ); Ram, S. ); Chin, A.A. ); Harandi, M.N.; Smith, C.M. )

    1993-09-13

    Although the linkage between gasoline benzene content and evaporative, running, and tailpipe emission is not yet defined, the U.S. 1990 Clean Air Act Amendments mandate a benzene content of less than 1.0 vol% in reformulated gasolines. Likewise, the California Air Resources Board plans to restrict benzene to less than about 0.8 vol %. Mobil Research and Development Corp. and Badger Co. Inc. have developed several alternatives for reducing benzene levels in gasoline. Where benzene extraction is viable and maximum catalytic reformer hydrogen is needed, the companies' cumene and ethylbenzene processes are desirable. Mobil's benzene reduction process can be an alternative to benzene hydrosaturation. All of these processes utilize low-value offgas from the fluid catalytic cracking (FCC) unit.

  15. Biomarkers of human exposure to benzene

    SciTech Connect

    Bechtold, W.E.; Henderson, R.F. )

    1993-01-01

    Three biomarkers for benzene exposure were developed. The first biomarker, muconic acid in urine, results from the ring opening of a benzene metabolite. A gas chromatography/mass spectroscopy (GC/MS) assay was developed to measure urinary muconic acid, and the analyte in urine samples from workers occupationally exposed to benzene was determined. Workers exposed to benzene concentrations as low as 4.4 ppm over an 8-h day showed higher urinary muconic acid concentrations than did any control individual (p < .005). The second biomarker, S-phenylcysteine (SPC) in hemoglobin (Hb), results from the addition of benzene oxide to a cysteine sulfhydryl group. A GC/MS assay was developed to measure SPC in the blood of F344/N rats and B67C3F mice exposed to benzene by inhalation. The cysteine moiety on rat Hb is at a more accessible site than on Hb of mice or humans, and rats showed considerably higher levels of SPC than did mice. As yet, we have been unable to detect SPC in the globin of humans occupationally exposed to benzene. The third biomarker is SPC in albumin. In humans occupationally exposed to average concentrations of 0, 4.4, 8.4, and 23.1 ppm benzene, 8 h/d, 5 d/wk, SPC increased in the exposed groups linearly, giving a statistically significant slope (p < .001) of 0.044 [+-] 0.008 pmol/mg albumin/ppm. The assay for SPC is arduous and often imprecise; assuming these difficulties can be overcome, muconic acid in urine and SPC in albumin may be useful for accurately determining benzene exposure. 25 refs., 4 figs., 1 tab.

  16. PTEN methylation involved in benzene-induced hematotoxicity.

    PubMed

    Yang, Jing; Zuo, Xin; Bai, Wenlin; Niu, Piye; Tian, Lin; Gao, Ai

    2014-06-01

    It is well known that benzene is a hematotoxic carcinogen. PTEN promoter methylation is a representative example of transcriptional silencing of tumor suppressor genes. However, the effect of PTEN methylation on benzene-induced hematotoxicity has not yet been elucidated. In this study, the animal model of benzene hematotoxicity was successfully established. WBC significantly decreased in experimental groups (P < 0.01). Compared with the control group, the weight of rats increased slowly and even declined with increasing doses of benzene in the benzene-treated groups. An increase in the level of PTEN methylation was observed in the low dose group, and PTEN methylation level increased significantly in a dose-dependent manner. However, it was interesting that PTEN mRNA expression increased in the low dose group, but declined with increasing doses of benzene. The decrease of tumor suppressor function caused by PTEN methylation may be an important mechanism of benzene hematotoxicity. Furthermore, lymphoblast cell line F32 was incubated by benzene and then treated with 5-aza and TSA, alone or in combination. A dramatic decrease in the PTEN mRNA expression and a significant increase of PTEN methylation level in benzene-treated cells were also shown. PTEN mRNA expression was up regulated and PTEN methylation level was reduced by the epigenetic inhibitors, 5-aza and TSA. In conclusion, PTEN methylation is involved in benzene-induced hematotoxicity through suppressing PTEN mRNA expression.

  17. Benzene release. status report

    SciTech Connect

    Dworjanyn, L.O.; Rappe, K.G.; Gauglitz, P.A.

    1997-11-04

    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.

  18. Benzene Monitor System report

    SciTech Connect

    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).

  19. [Building Change Detection Based on Multi-Level Rules Classification with Airborne LiDAR Data and Aerial Images].

    PubMed

    Gong, Yi-long; Yan, Li

    2015-05-01

    The present paper proposes a new building change detection method combining Lidar point cloud with aerial image, using multi-level rules classification algorithm, to solve building change detection problem between these two kinds of heterogeneous data. Then, a morphological post-processing method combined with area threshold is proposed. Thus, a complete building change detection processing flow that can be applied to actual production is proposed. Finally, the effectiveness of the building change detection method is evaluated, processing the 2010 airborne LiDAR point cloud data and 2009 high resolution aerial image of Changchun City, Jilin province, China; in addition, compared with the object-oriented building change detection method based on support vector machine (SVM) classification, more analysis and evaluation of the suggested method is given. Experiment results show that the performance of the proposed building change detection method is ideal. Its Kappa index is 0. 90, and correctness is 0. 87, which is higher than the object-oriented building change detection method based on SVM classification.

  20. Determinants of indoor benzene in Europe

    NASA Astrophysics Data System (ADS)

    Lai, H. K.; Jantunen, M. J.; Künzli, N.; Kulinskaya, E.; Colvile, R.; Nieuwenhuijsen, M. J.

    This study identified the key determinants associated with the indoor benzene concentrations that were measured between 1996 and 2000 using the EXPOLIS protocol in the residences of six European cities, including Athens (Greece), Basel (Switzerland), Helsinki (Finland), Milan (Italy), Oxford (United Kingdom), and Prague (Czech Republic). Two consecutive days of home indoor and home outdoor measurements of benzene were carried out at the homes of adult participants on different dates and seasons during the sampling period. Regression models, with interactions searched by all-possible subset method, were used to assess the city effects and the determinants of home indoor benzene (adjusted R2=0.57, n=412). Outdoor benzene concentrations, outdoor temperature, wind speed, the use of anti-moth products, and indoor smoking in terms of number of cigarettes consumed per day were shown to be the key determinants of indoor benzene concentrations. The model was further used to predict the indoor benzene levels in cities. Non-linear relationships were commonly found, indicating that a unit change in the indoor concentration cannot be simply estimated by a proportional change of the determinant, and the pattern of relationships could be differed in different places. This finding is important in formulating indoor air quality guidelines as well as calculating an accurate health risk estimate based on the estimates of population's lifetime exposure levels.

  1. Airborne manganese as dust vs. fume determining blood levels in workers at a manganese alloy production plant.

    PubMed

    Park, Robert M; Baldwin, Mary; Bouchard, Maryse F; Mergler, Donna

    2014-12-01

    The appropriate exposure metrics for characterizing manganese (Mn) exposure associated with neurobehavioral effects have not been established. Blood levels of Mn (B-Mn) provide a potentially important intermediate marker of Mn airborne exposures. Using data from a study of a population of silicon- and ferro-manganese alloy production workers employed between 1973 and 1991, B-Mn levels were modeled in relation to prior Mn exposure using detailed work histories and estimated respirable Mn concentrations from air-sampling records. Despite wide variation in exposure levels estimated for individual jobs, duration of employment (exposure) was itself a strong predictor of B-Mn levels and strongest when an 80-day half-life was applied to contributions over time (t=6.95, 7.44, respectively; p<10(-5)). Partitioning exposure concentrations based on process origin into two categories: (1) "large" respirable particulate (Mn-LRP) derived mainly from mechanically generated dust, and (2) "small" respirable particulate (Mn-SRP) primarily electric furnace condensation fume, revealed that B-Mn levels largely track the small, fume exposures. With a half-life of 65 days applied in a model with cumulative exposure terms for both Mn-LRP (t=-0.16, p=0.87) and Mn-SRP (t=6.45, p<10(-5)), the contribution of the large-size fraction contribution was negligible. Constructing metrics based on the square root of SRP exposure concentrations produced a better model fit (t=7.87 vs. 7.44, R(2)=0.2333 vs. 0.2157). In a model containing both duration (t=0.79, p=0.43) and (square root) fume (t=2.47, p=0.01) metrics, the duration term was a weak contributor. Furnace-derived, small respirable Mn particulate appears to be the primary contributor to B-Mn levels, with a dose-rate dependence in a population chronically exposed to Mn, with air-concentrations declining in recent years. These observations may reflect the presence of homeostatic control of Mn levels in the blood and other body tissues and be

  2. A real time sorbent based air monitoring system for determining low level airborne exposure levels to Lewisite

    SciTech Connect

    Lattin, F.G.; Paul, D.G.; Jakubowski, E.M.

    1994-12-31

    The Real Time Analytical Platform (RTAP) is designed to provide mobile, real-time monitoring support to ensure protection of worker safety in areas where military unique compounds are used and stored, and at disposal sites. Quantitative analysis of low-level vapor concentrations in air is accomplished through sorbent-based collection with subsequent thermal desorption into a gas chromatograph (GC) equipped with a variety of detectors. The monitoring system is characterized by its sensitivity (ability to measure at low concentrations), selectivity (ability to filter out interferences), dynamic range and linearity, real time mode (versus methods requiring extensive sample preparation procedures), and ability to interface with complimentary GC detectors. This presentation describes an RTAP analytical method for analyzing lewisite, an arsenical compound, that consists of a GC screening technique with an Electron Capture Detector (ECD), and a confirmation technique using an Atomic Emission Detector (AED). Included in the presentation is a description of quality assurance objectives in the monitoring system, and an assessment of method accuracy, precision and detection levels.

  3. Benzene and leukemia. An epidemiologic risk assessment

    SciTech Connect

    Rinsky, R.A.; Smith, A.B.; Hornung, R.; Filloon, T.G.; Young, R.J.; Okun, A.H.; Landrigan, P.J.

    1987-04-23

    To assess quantitatively the association between benzene exposure and leukemia, we examined the mortality rate of a cohort with occupational exposure to benzene. Cumulative exposure for each cohort member was estimated from historical air-sampling data and, when no sampling data existed, from interpolation on the basis of existing data. The overall standardized mortality ratio (a measure of relative risk multiplied by 100) for leukemia was 337 (95 percent confidence interval, 154 to 641), and that for multiple myeloma was 409 (95 percent confidence interval, 110 to 1047). With stratification according to levels of cumulative exposure, the standardized mortality ratios for leukemia increased from 109 to 322, 1186, and 6637 with increases in cumulative benzene exposure from less than 40 parts per million-years (ppm-years), to 40 to 199, 200 to 399, and 400 or more, respectively. A cumulative benzene exposure of 400 ppm-years is equivalent to a mean annual exposure of 10 ppm over a 40-year working lifetime; 10 ppm is the currently enforceable standard in the United States for occupational exposure to benzene. To examine the shape of the exposure-response relation, we performed a conditional logistic-regression analysis, in which 10 controls were matched to each cohort member with leukemia. From this model, it can be calculated that protection from benzene-induced leukemia would increase exponentially with any reduction in the permissible exposure limit.

  4. Characterizing historical industrial hygiene data: a case study involving benzene exposures at a chemical manufacturing facility (1976-1987).

    PubMed

    Williams, Pamela R D; Paustenbach, Dennis J

    2005-07-01

    This article describes how nearly 3700 air samples of benzene collected in a typical chemical manufacturing (acetic acid) facility in the United States from 1976 to 1987 were used to characterize daily time-weighted average (TWA) exposure levels. We found that those workers directly involved in manufacturing operations had likely TWA exposures to benzene of about 2.0 ppm from 1976-1981 and about 1.0 ppm from 1982-1987. These results are consistent with the improved industrial hygiene programs at chemical facilities, which often occurred following the adoption of stricter occupational exposure limits. Additionally, about 97% of all personal TWA samples had reported benzene concentrations less than 10 ppm, which was the permissible exposure limit in place prior to 1987. Because one of the primary objectives of historical workplace air sampling efforts was to understand the source of release of contaminants, a large number of short-term (typically about 1 min) area samples were also collected. Although these types of samples are often not useful for predicting human exposure without time-motion information, airborne benzene concentrations were about five- to tenfold higher for many of the short-term area samples than for the personal TWA measurements. The methodology presented here should be useful for evaluating industrial hygiene data collected after the early 1970s (after the promulgation of OSHA), and our findings support prior reports that large corporations in the United States have tended to reduce workplace exposures to airborne contaminants consistent with historical changes in occupational exposure limits.

  5. Attenuation of aqueous benzene in soils under saturated flow conditions.

    PubMed

    Kim, S-B; Kim, D-J; Yun, S-T

    2006-01-01

    The fate of aqueous benzene in subsurface was investigated in this study, focusing on the role of sorption and biodegradation on the benzene attenuation under dynamic flow conditions. Two sets of column tests were conducted in Plexiglass flow cells packed uniformly with sandy aquifer materials. The first set of the experiment was conducted with a step-type injection of benzene with different powder activated carbon (PAC) contents: (1) PAC = 0 %; (2) PAC = 0.5 %; (3) PAC = 2.0%. The second set was performed as a pulse-type with different test conditions: (4) benzene; (5) benzene and bacteria (Pseudomonas aeruginosa); (6) benzene and bacteria (P. aeruginosa) with hydrogen peroxide. In addition, numerical experiments were performed to examine the role of sorption processes on the benzene attenuation. In the step mode experiments, the KCl breakthrough curves (BTCs) reached the input concentration while the benzene BTCs were considerably lower than those of KCl with slight retardation for all cases, indicating that both reversible/retardation and irreversible sorption occurred. The pulse type tests showed that attenuation of benzene increased in the presence of bacteria due to biodegradation. The benzene attenuation by microbial degradation increased furthermore in the presence of hydrogen peroxide owing to sufficient supply of dissolved oxygen in soil column. Numerical experiments demonstrated that retardation could not contribute to the attenuation of benzene in soils but could only extend its breakthrough time. Experimental results indicated that aqueous benzene could be attenuated by irreversible sorption and biodegradation during transport through the subsurface. Additionally, the attenuation of aqueous benzene is closely related to organic carbon content and oxygen level existing in contaminated aquifers.

  6. Leukemia and Benzene

    PubMed Central

    Snyder, Robert

    2012-01-01

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

  7. Genotoxicity of intermittent co-exposure to benzene and toluene in male CD-1 mice.

    PubMed

    Wetmore, Barbara A; Struve, Melanie F; Gao, Pu; Sharma, Sheela; Allison, Neil; Roberts, Kay C; Letinski, Daniel J; Nicolich, Mark J; Bird, Michael G; Dorman, David C

    2008-06-17

    Benzene is an important industrial chemical. At certain levels, benzene has been found to produce aplastic anemia, pancytopenia, myeloblastic anemia and genotoxic effects in humans. Metabolism by cytochrome P450 monooxygenases and myeloperoxidase to hydroquinone, phenol, and other metabolites contributes to benzene toxicity. Other xenobiotic substrates for cytochrome P450 can alter benzene metabolism. At high concentrations, toluene has been shown to inhibit benzene metabolism and benzene-induced toxicities. The present study investigated the genotoxicity of exposure to benzene and toluene at lower and intermittent co-exposures. Mice were exposed via whole-body inhalation for 6h/day for 8 days (over a 15-day time period) to air, 50 ppm benzene, 100 ppm toluene, 50 ppm benzene and 50 ppm toluene, or 50 ppm benzene and 100 ppm toluene. Mice exposed to 50 ppm benzene exhibited an increased frequency (2.4-fold) of micronucleated polychromatic erythrocytes (PCE) and increased levels of urinary metabolites (t,t-muconic acid, hydroquinone, and s-phenylmercapturic acid) vs. air-exposed controls. Benzene co-exposure with 100 ppm toluene resulted in similar urinary metabolite levels but a 3.7-fold increase in frequency of micronucleated PCE. Benzene co-exposure with 50 ppm toluene resulted in a similar elevation of micronuclei frequency as with 100 ppm toluene which did not differ significantly from 50 ppm benzene exposure alone. Both co-exposures - 50 ppm benzene with 50 or 100 ppm toluene - resulted in significantly elevated CYP2E1 activities that did not occur following benzene or toluene exposure alone. Whole blood glutathione (GSH) levels were similarly decreased following exposure to 50 ppm benzene and/or 100 ppm toluene, while co-exposure to 50 ppm benzene and 100 ppm toluene significantly decreased GSSG levels and increased the GSH/GSSG ratio. The higher frequency of micronucleated PCE following benzene and toluene co-exposure when compared with mice exposed to

  8. The electronic structure and molecular symmetry of pure benzene and benzene coadsorbed with CO on Ni(111)

    NASA Astrophysics Data System (ADS)

    Huber, W.; Steinrück, H.-P.; Pache, T.; Menzel, D.

    1989-07-01

    Benzene adsorption on Ni(111) was studied by ARUPS using linearly polarized synchrotron radiation at various benzene coverages and for benzene coadsorbed with CO. Overall the electronic structure of chemisorbed benzene is found to be very similar for the different benzene coverages and in the presence of coadsorbed CO: only small shifts in the electronic binding energies are observed which are attributed to electrostatic initial state changes. Using dipole selection rules the orientation of the adsorbed benzene molecules is determined to be parallel to the surface for all layers investigated. The molecular symmetry is reduced to C 3v in all cases. The photon energy dependence of the photoionization cross section shows a pronounced resonance of the 2e 1u level at a photon energy of 25 eV ( Ekin ≈ 13 eV); the corresponding electron emission is centered along the surface normal. This resonance is attributed to a shape resonance into an a 1 final state.

  9. Airborne Transparencies.

    ERIC Educational Resources Information Center

    Horne, Lois Thommason

    1984-01-01

    Starting from a science project on flight, art students discussed and investigated various means of moving in space. Then they made acetate illustrations which could be used as transparencies. The projection phenomenon made the illustrations look airborne. (CS)

  10. Urinary excretion of unmetabolized benzene as an indicator of benzene exposure.

    PubMed

    Ghittori, S; Fiorentino, M L; Maestri, L; Cordioli, G; Imbriani, M

    1993-03-01

    Benzene concentrations in urine samples (Cu, ng/L) from 110 workers exposed to benzene in chemical plants and gasoline pumps were determined by injecting urine supernate into a gas chromatograph. The urine was saturated with anhydrous N2SO4 to facilitate the passage of benzene in the air over the urine. The solvent was stripped from the urine surface and concentrated on an adsorbent substrate (Carbotrap tube) by means of a suction pump (flow rate 150 ml/m). Wash-up of the head space was achieved by simultaneous intake of filtered air through charcoal. Benzene was thermically desorbed and injected in a column (thermal tube disorder, Supelco; 370 degrees C thermal flash; borosilicate capillary glass column SPB-1, 60 m length, 0.75 mm ID, 1 microns film thickness; GC Dani 8580-FID). Benzene concentrations in the urine from 40 non-exposed subjects (20 smokers > 20 cigarette/d and 20 nonsmokers) were also determined [median value of 790 ng/L (10.17 nmol/L) and 131 ng/L (1.70 nmol/L), respectively]. The 8-h time-weighted exposure intensity (Cl, micrograms/m3) of individual workers was monitored by means of charcoal tubes. The median value for exposure to benzene was 736 micrograms/m3 (9.42 mumol/m3) [geometric standard deviation (GSD) = 2.99; range 64 micrograms/m3 (0.82 mumol/m3) to 13,387 micrograms/m3) (171.30 mumol/m3)]. The following linear correlation was found between benzene concentrations in urine (Cu, ng/L) and benzene concentrations in the breathing zone (Cl, micrograms/m3): log(Cu) = 0.645 x log(Cl) + 1.399 r = .559, n = 110, p < .0001 With exclusion of workers who smoked from the study, the correlation between air benzene concentration and benzene measured in urine was: log(Cu) = 0.872 x log(Cl) + 0.6 r = .763, n = 63, p < .0001 The study results indicate that the urinary level of benzene is an indicator of occupational exposure to benzene.

  11. Variation in airborne 137Cs peak levels with altitude from high-altitude locations across Europe after the arrival of Fukushima-labeled air masses

    NASA Astrophysics Data System (ADS)

    Masson, Olivier; Bieringer, Jacqueline; Dalheimer, Axel; Estier, Sybille; Evrard, Olivier; Penev, Ilia; Ringer, Wolfgang; Schlosser, Clemens; Steinkopff, Thomas; Tositti, Laura; de Vismes-Ott, Anne

    2015-04-01

    During the Fukushima Daiichi nuclear power plant (FDNPP) accident, a dozen of high-altitude aerosol sampling stations, located between 850 and 3,454 m above sea level (a.s.l.), provided airborne activity levels across Europe (Fig. 1). This represents at most 5% of the total number of aerosol sampling locations that delivered airborne activity levels (at least one result) in Europe, in connection with this nuclear accident. High altitude stations are typically equipped with a high volume sampler that collects aerosols on filters. The Fukushima-labeled air mass arrival and the peak of airborne cesium-137 (137Cs) activity levels were registered in Europe at different dates depending on the location, with differences up to a factor of six on a regional scale. Besides this statement related to lowland areas, we have compared the maximum airborne levels registered at high-altitude European locations (850 m < altitudes < 3450 m) with what was observed at the closest lowland location. The vertical distribution of 137Cs peak level was not uniform even after a long travel time/distance from Japan. This being true at least in the atmospheric boundary layer and in the lower free troposphere. Moreover the relation '137Csmax vs. altitude' shows a decreasing trend (Fig. 2). Results and discussion : Comparison of 137Cs and 7Be levels shows simultaneous increases at least when the 137Cs airborne level rose for the first time (Fig. 3). Zugspitze and Jungfraujoch stations attest of a time shift between 7Be and 137Cs peak that can be due to the particular dynamic of air movements at such high altitudes. After the 137Cs peak value, the plume concentration decreased whatever the 7Be level. Due to the cosmogenic origin of 7Be, its increase in the ground-level air is usually associated with downwind air movements, i.e. stratospheric air intrusions or at least air from high-tropospheric levels, into lower atmospheric layers. This means that Fukushima-labeled air masses registered at ground

  12. Benzene as a Chemical Hazard in Processed Foods.

    PubMed

    Salviano Dos Santos, Vânia Paula; Medeiros Salgado, Andréa; Guedes Torres, Alexandre; Signori Pereira, Karen

    2015-01-01

    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. PMID:26904662

  13. Benzene as a Chemical Hazard in Processed Foods

    PubMed Central

    Salviano dos Santos, Vânia Paula; Medeiros Salgado, Andréa; Guedes Torres, Alexandre; Signori Pereira, Karen

    2015-01-01

    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. PMID:26904662

  14. Benzene as a Chemical Hazard in Processed Foods.

    PubMed

    Salviano Dos Santos, Vânia Paula; Medeiros Salgado, Andréa; Guedes Torres, Alexandre; Signori Pereira, Karen

    2015-01-01

    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.

  15. An overview of benzene metabolism.

    PubMed Central

    Snyder, R; Hedli, C C

    1996-01-01

    Benzene toxicity involves both bone marrow depression and leukemogenesis caused by damage to multiple classes of hematopoietic cells and a variety of hematopoietic cell functions. Study of the relationship between the metabolism and toxicity of benzene indicates that several metabolites of benzene play significant roles in generating benzene toxicity. Benzene is metabolized, primarily in the liver, to a variety of hydroxylated and ring-opened products that are transported to the bone marrow where subsequent secondary metabolism occurs. Two potential mechanisms by which benzene metabolites may damage cellular macromolecules to induce toxicity include the covalent binding of reactive metabolites of benzene and the capacity of benzene metabolites to induce oxidative damage. Although the relative contributions of each of these mechanisms to toxicity remains unestablished, it is clear that different mechanisms contribute to the toxicities associated with different metabolites. As a corollary, it is unlikely that benzene toxicity can be described as the result of the interaction of a single metabolite with a single biological target. Continued investigation of the metabolism of benzene and its metabolites will allow us to determine the specific combination of metabolites as well as the biological target(s) involved in toxicity and will ultimately lead to our understanding of the relationship between the production of benzene metabolites and bone marrow toxicity. PMID:9118888

  16. Retrieval of effective leaf area index (LAIe) and leaf area density (LAD) profile at individual tree level using high density multi-return airborne LiDAR

    NASA Astrophysics Data System (ADS)

    Lin, Yi; West, Geoff

    2016-08-01

    As an important canopy structure indicator, leaf area index (LAI) proved to be of considerable implications for forest ecosystem and ecological studies, and efficient techniques for accurate LAI acquisitions have long been highlighted. Airborne light detection and ranging (LiDAR), often termed as airborne laser scanning (ALS), once was extensively investigated for this task but showed limited performance due to its low sampling density. Now, ALS systems exhibit more competing capacities such as high density and multi-return sampling, and hence, people began to ask the questions like-"can ALS now work better on the task of LAI prediction?" As a re-examination, this study investigated the feasibility of LAI retrievals at the individual tree level based on high density and multi-return ALS, by directly considering the vertical distributions of laser points lying within each tree crown instead of by proposing feature variables such as quantiles involving laser point distribution modes at the plot level. The examination was operated in the case of four tree species (i.e. Picea abies, Pinus sylvestris, Populus tremula and Quercus robur) in a mixed forest, with their LAI-related reference data collected by using static terrestrial laser scanning (TLS). In light of the differences between ALS- and TLS-based LAI characterizations, the methods of voxelization of 3D scattered laser points, effective LAI (LAIe) that does not distinguish branches from canopies and unified cumulative LAI (ucLAI) that is often used to characterize the vertical profiles of crown leaf area densities (LADs) was used; then, the relationships between the ALS- and TLS-derived LAIes were determined, and so did ucLAIs. Tests indicated that the tree-level LAIes for the four tree species can be estimated based on the used airborne LiDAR (R2 = 0.07, 0.26, 0.43 and 0.21, respectively) and their ucLAIs can also be derived. Overall, this study has validated the usage of the contemporary high density multi

  17. Fourth Airborne Geoscience Workshop

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The focus of the workshop was on how the airborne community can assist in achieving the goals of the Global Change Research Program. The many activities that employ airborne platforms and sensors were discussed: platforms and instrument development; airborne oceanography; lidar research; SAR measurements; Doppler radar; laser measurements; cloud physics; airborne experiments; airborne microwave measurements; and airborne data collection.

  18. Molecular dynamics simulations of the effects of salts on the aggregation properties of benzene in water.

    SciTech Connect

    Smith, P. E.

    2003-07-16

    The specific aims of the project were: to provide an atomic level description of the interactions between benzene, water and ions in solutions. To determine the degree of association between two benzene molecules in aqueous and salt solutions. To investigate the structure and dynamics of the interface between benzene and water or salt solution.

  19. Quantifying Airborne Allergen Levels Before and After Rain Events Using TRMM/GPM and Ground-Sampled Data

    NASA Technical Reports Server (NTRS)

    Stewart, Randy M.

    2006-01-01

    Allergies affect millions of Americans, increasing health risks and also increasing absenteeism and reducing productivity in the workplace. Outdoor allergens, such as airborne pollens and mold spores, commonly trigger respiratory distress symptoms, but rainfall reduces the quantity of allergens in the air (EPA, 2003). The current NASA Tropical Rainfall Measuring Mission provides accurate information related to rain events. These capabilities will be further enhanced with the future Global Precipitation Measurement mission. This report examines the effectiveness of combining these NASA resources with established ground-based allergen/spore sampling systems to better understand the benefits that rain provides in removing allergens and spores from the air.

  20. Airborne Imagery

    NASA Technical Reports Server (NTRS)

    1983-01-01

    ATM (Airborne Thematic Mapper) was developed for NSTL (National Space Technology Companies) by Daedalus Company. It offers expanded capabilities for timely, accurate and cost effective identification of areas with prospecting potential. A related system is TIMS, Thermal Infrared Multispectral Scanner. Originating from Landsat 4, it is also used for agricultural studies, etc.

  1. Acute high dose exposure to benzene in shipyard workers

    SciTech Connect

    Midzenski, M.A.; McDiarmid, M.A.; Rothman, N.; Kolodner, K. )

    1992-01-01

    Fifteen degassers were acutely exposed over several days to high concentrations (> 60 ppm) of benzene during removal of residual fuel (degassing) from shipboard fuel tanks. Medical surveillance evaluation mandated by the Occupational Safety and Health Administration's (OSHA) Benzene Standard initially revealed 11 workers (73%) reporting neurotoxic symptoms while degassing. Workers with more than 2 days (16 hours) of acute exposure were significantly more likely to report dizziness and nausea than those with 2 or fewer days of acute exposure. Repeated laboratory analyses performed over a 4-month period after the acute exposure revealed at least one hematologic abnormality consistent with benzene exposure in 9 (60%) of these degassers. One year later, 6 workers (40%) had persistent abnormalities; an additional worker with normal hematologic parameters at the time of our initial evaluation subsequently developed an abnormality consistent with benzene exposure. Numerous large granular lymphocytes were observed on 6 (40%) of the peripheral blood smears. Despite these laboratory findings, there were no significant associations between the presence of hematologic abnormalities and either the number of hours of acute benzene exposure or the duration of employment as a degasser. Volatilization of benzene from the residual fuel was the suspected source of benzene in the headspace of tanks. Confined space exposure to petroleum products may be exposing workers to benzene at levels above the OSHA Short-Term Exposure Limit (STEL). This situation warrants further study.

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

    PubMed

    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

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

    PubMed

    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.

  4. Levels and risk assessment for humans and ecosystems of platinum-group elements in the airborne particles and road dust of some European cities.

    PubMed

    Gómez, B; Palacios, M A; Gómez, M; Sanchez, J L; Morrison, G; Rauch, S; McLeod, C; Ma, R; Caroli, S; Alimonti, A; Petrucci, E; Bocca, B; Schramel, P; Zischka, M; Petterson, C; Wass, U

    2002-11-01

    Traffic is the main source of platinum-group element (PGE) contamination in populated urban areas. There is increasing concern about the hazardous effects of these new pollutants for people and for other living organisms in these areas. Airborne and road dusts, as well as tree bark and grass samples were collected at locations in the European cities of Göteborg (Sweden), Madrid (Spain), Rome (Italy), Munich (Germany), Sheffield and London (UK). Today, in spite of the large number of parameters that can influence the airborne PGE content, the results obtained so far indicate significantly higher PGE levels at traffic sites compared with the rural or non-polluted zones that have been investigated (background levels). The average Pt content in airborne particles found in downtown Madrid, Göteborg and Rome is in the range 7.3-13.1 pg m(-3). The ring roads of these cities have values in the range 4.1-17.7 pg m(-3). In Munich, a lower Pt content was found in airborne particles (4.1 pg m(-3)). The same tendency has been noted for downtown Rh, with contents in the range 2.2-2.8 pg m(-3), and in the range 0.8-3.0 and 0.3 pg m(-3) for motorway margins in Munich. The combined results obtained using a wide-range airborne classifier (WRAC) collector and a PM-10 or virtual impactor show that Pt is associated with particles for a wide range of diameters. The smaller the particle size, the lower the Pt concentration. However, in particles levels for which adverse

  5. Benzene oxidation coupled to sulfate reduction

    USGS Publications Warehouse

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

    1995-01-01

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

  6. Benzene Exposures and Risk Potential for Vehicle Mechanics from Gasoline and Petroleum-Derived Products.

    PubMed

    Williams, Pamela R D; Mani, Ashutosh

    2015-01-01

    Benzene exposures among vehicle mechanics in the United States and abroad were characterized using available data from published and unpublished studies. In the United States, the time-weighted-average (TWA) airborne concentration of benzene for vehicle mechanics averaged 0.01-0.05 ppm since at least the late 1970s, with maximal TWA concentrations ranging from 0.03 to 0.38 ppm. Benzene exposures were notably lower in the summer than winter and in the Southwest compared to other geographic regions, but significantly higher during known gasoline-related tasks such as draining a gas tank or changing a fuel pump or fuel filter. Measured airborne concentrations of benzene were also generally greater for vehicle mechanics in other countries, likely due to the higher benzene content of gasoline and other factors. Short-term airborne concentrations of benzene frequently exceeded 1 ppm during gasoline-related tasks, but remained below 0.2 ppm for tasks involving other petroleum-derived products such as carburetor and brake cleaner or parts washer solvent. Application of a two-zone mathematical model using reasonable input values from the literature yielded predicted task-based benzene concentrations during gasoline and aerosol spray cleaner scenarios similar to those measured for vehicle mechanics during these types of tasks. When evaluated using appropriate biomarkers, dermal exposures were found to contribute little to total benzene exposures for this occupational group. Available data suggest that vehicle mechanics have not experienced significant exposures to benzene in the workplace, except perhaps during short-duration gasoline-related tasks, and full-shift benzene exposures have remained well below current and contemporaneous occupational exposure limits. These findings are consistent with epidemiology studies of vehicle mechanics, which have not demonstrated an increased risk of benzene-induced health effects in this cohort of workers. Data and information presented

  7. Benzene Exposures and Risk Potential for Vehicle Mechanics from Gasoline and Petroleum-Derived Products.

    PubMed

    Williams, Pamela R D; Mani, Ashutosh

    2015-01-01

    Benzene exposures among vehicle mechanics in the United States and abroad were characterized using available data from published and unpublished studies. In the United States, the time-weighted-average (TWA) airborne concentration of benzene for vehicle mechanics averaged 0.01-0.05 ppm since at least the late 1970s, with maximal TWA concentrations ranging from 0.03 to 0.38 ppm. Benzene exposures were notably lower in the summer than winter and in the Southwest compared to other geographic regions, but significantly higher during known gasoline-related tasks such as draining a gas tank or changing a fuel pump or fuel filter. Measured airborne concentrations of benzene were also generally greater for vehicle mechanics in other countries, likely due to the higher benzene content of gasoline and other factors. Short-term airborne concentrations of benzene frequently exceeded 1 ppm during gasoline-related tasks, but remained below 0.2 ppm for tasks involving other petroleum-derived products such as carburetor and brake cleaner or parts washer solvent. Application of a two-zone mathematical model using reasonable input values from the literature yielded predicted task-based benzene concentrations during gasoline and aerosol spray cleaner scenarios similar to those measured for vehicle mechanics during these types of tasks. When evaluated using appropriate biomarkers, dermal exposures were found to contribute little to total benzene exposures for this occupational group. Available data suggest that vehicle mechanics have not experienced significant exposures to benzene in the workplace, except perhaps during short-duration gasoline-related tasks, and full-shift benzene exposures have remained well below current and contemporaneous occupational exposure limits. These findings are consistent with epidemiology studies of vehicle mechanics, which have not demonstrated an increased risk of benzene-induced health effects in this cohort of workers. Data and information presented

  8. Benzene exposures associated with tasks performed on marine vessels (circa 1975 to 2000).

    PubMed

    Williams, Pamela R D; Robinson, Kathryn; Paustenbach, Dennis J

    2005-11-01

    In this article, we assemble and synthesize the available industrial hygiene data that describe exposure during the marine transport of benzene-containing products in the United States and abroad. A total of 25 studies were identified and summarized. The measured airborne concentrations of benzene on marine vessels were found to vary depending on several key factors, including the job task, vessel characteristics, cargo type, and sample type and duration. Despite the differences in sampling strategies and benzene content of the liquids being transported, personal time-weighted-average benzene air concentrations typically ranged from 0.2-2.0 ppm during closed loading and 2-10 ppm during open loading operations. Benzene exposures during these activities are likely due to specific short-term tasks, such as connecting and disconnecting hoses and tank gauging and sampling. Similar concentrations of benzene have been reported in the pump room during marine loading operations and during tank cleaning activities in various settings. When compared with contemporaneous occupational health standards, our review indicates that most activities performed on marine vessels from the 1970s to 1990s usually did not result in benzene exposures that exceeded these standards. The information and data presented here may be useful for quantitatively estimating or reconstructing historical exposures during the marine transport of benzene-containing cargo if details about individual's work histories in the maritime industry are available.

  9. BENZENE OXIDE PROTEIN ADDUCTS AS BIOMARKERS OF BENZENE EXPOSURE

    EPA Science Inventory

    Benzene is known to be hematotoxic and carcinogenic in animals and humans. While metabolism is required for toxicity, the identity of the ultimate carcinogen(s) remains unknown. Benzene oxide (BO) is the first and most abundant of the metabolites, but very little is known about...

  10. Hematotoxicity and carcinogenicity of benzene

    SciTech Connect

    Aksoy, M. )

    1989-07-01

    The hematotoxicity of benzene exposure has been well known for a century. Benzene causes leukocytopenia, thrombocytopenia, pancytopenia, etc. The clinical and hematologic picture of aplastic anemia resulting from benzene exposure is not different from classical aplastic anemia; in some cases, mild bilirubinemia, changes in osmotic fragility, increase in lactic dehydrogenase and fecal urobilinogen, and occasionally some neurological abnormalities are found. Electromicroscopic findings in some cases of aplastic anemia with benzene exposure were similar to those observed by light microscopy. Benzene hepatitis-aplastic anemia syndrome was observed in a technician with benzene exposure. Ten months after occurrence of hepatitis B, a severe aplastic anemia developed. The first epidemiologic study proving the leukemogenicity of benzene was performed between 1967 and 1973 to 1974 among shoe workers in Istanbul. The incidence of leukemia was 13.59 per 100,000, which is a significant increase over that of leukemia in the general population. Following the prohibition and discontinuation of the use of benzene in Istanbul, there was a striking decrease in the number of leukemic shoe workers in Istanbul. In 23.7% of the series, consisting of 59 leukemic patients with benzene exposure, there was a preceding pancytopenic period. Furthermore, a familial connection was found in 10.2% of them. The 89.8% of the series showed the findings of acute leukemia. The possible factors that may determine the types of leukemia in benzene toxicity are discussed. The possible role of benzene exposure is presented in the development of malignant lymphoma, multiple myeloma, and lung cancer.

  11. Benzene upgrading reformer integration

    SciTech Connect

    Harandi, M.N.; Owen, H.

    1990-08-21

    This patent describes a continuous process for providing an integrated product recovery system for a primary catalytic hydrocarbon reforming reactor and a secondary catalytic olefins oligomerization-alkylation reactor. It comprises: withdrawing reformer effluent from primary reformer reactor; separating in a primary separation zone the reformer effluent into a primary overhead stream comprising noncondensible light paraffins and a primary bottoms stream comprising C{sub 6} to C{sub 8} aromatic hydrocarbons; withdrawing oligomerization effluent from secondary oligomerization-alkylation reactor; separating in a secondary separation zone the oligomerization effluent into a secondary overhead stream; adding the primary bottoms stream and the secondary bottoms stream to the fractionation column; withdrawing from the top of the fractionation column a stream comprising C{sub 4} {minus} hydrocarbons; withdrawing from the bottom of the fractionation column a stream comprising C{sub 5} + hydrocarbons; adding the C{sub 5} + hydrocarbon stream to the reboiler unit; withdrawing from the reboiler unit a vapor stream comprising benzene and a liquid stream comprising C{sub 5} + hydrocarbons boiling in the gasoline range; adding at least a portion of the vapor stream comprising benzene to the secondary catalytic olefins oligomerization-alkylation reactor; and adding a light olefins feedstream.

  12. Environmental and biological monitoring of benzene in traffic policemen, police drivers and rural outdoor male workers.

    PubMed

    Manuela, Ciarrocca; Francesco, Tomei; Tiziana, Caciari; Assunta, Capozzella; Lara, Scimitto; Nadia, Nardone; Giorgia, Andreozzi; Barbara, Scala; Maria, Fiaschetti; Carlotta, Cetica; Valeria, Di Giorgio; Pia, Schifano Maria; Gianfranco, Tomei; Angela, Sancini

    2012-05-01

    To evaluate exposure to benzene in urban and rural areas, an investigation into personal exposure to benzene in traffic policemen, police drivers and rural (roadmen) male outdoor workers was carried out. Personal samples and data acquired using fixed monitoring stations located in different areas of the city were used to measure personal exposure to benzene in 62 non-smoker traffic policemen, 22 police drivers and 57 roadmen. Blood benzene, urinary trans-trans muconic acid (t,t-MA) and S-phenyl-mercapturic acid (S-PMA) were measured at the end of work shift in 62 non-smoker traffic policemen, 22 police drivers and 57 roadmen and 34 smoker traffic policemen, 21 police drivers and 53 roadmen. Exposure to benzene was similar among non-smoker traffic policemen and police drivers and higher among non-smoker urban workers compared to rural workers. Blood benzene, t,t-MA and S-PMA were similar among non-smoker traffic policemen and police drivers; blood benzene and t,t-MA were significantly higher in non-smoker urban workers compared to rural workers. Significant increases in t,t-MA were found in smokers vs. non-smokers. In non-smoker urban workers airborne benzene and blood benzene, and t,t-MA and S-PMA were significantly correlated. This study gives an evaluation of the exposure to benzene in an urban area, comparing people working in the street or in cars, to people working in a rural area. Benzene is a certain carcinogen for humans. The results we showed should lead to more in-depth studies about the effects on health of these categories of workers.

  13. Benzene exposure and the effect of traffic pollution in Copenhagen, Denmark

    NASA Astrophysics Data System (ADS)

    Skov, Henrik; Hansen, Asger B.; Lorenzen, Gitte; Andersen, Helle Vibeke; Løfstrøm, Per; Christensen, Carsten S.

    Benzene is a carcinogenic compound, which is emitted from petrol-fuelled cars and thus is found ubiquitous in all cities. As part of the project Monitoring of Atmospheric Concentrations of Benzene in European Towns and Homes (MACBETH) six campaigns were carried out in the Municipality of Copenhagen, Denmark. The campaigns were distributed over 1 year. In each campaign, the personal exposure to benzene of 50 volunteers (non-smokers living in non-smoking families) living and working in Copenhagen was measured. Simultaneously, benzene was measured in their homes and in an urban network distributed over the municipality. The Radiello diffusive sampler was applied to sample 5 days averages of benzene and other hydrocarbons. Comparison of the results with those from a BTX-monitor showed excellent agreement. The exposure and the concentrations in homes and in the urban area were found to be close to log-normal distribution. The annual averages of the geometrical mean values were 5.22, 4.30 and 2.90 μg m -3 for personal exposure, home concentrations and urban concentrations, respectively. Two main parameters are controlling the general level of benzene in Copenhagen: firstly, the emission from traffic and secondly, dispersion due to wind speed. The general level of exposure to benzene and home concentrations of benzene were strongly correlated with the outdoor level of benzene, which indicated that traffic is an important source for indoor concentrations of benzene and for the exposure to benzene.

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

    PubMed

    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

  15. Airborne asbestos in buildings.

    PubMed

    Lee, R J; Van Orden, D R

    2008-03-01

    The concentration of airborne asbestos in buildings nationwide is reported in this study. A total of 3978 indoor samples from 752 buildings, representing nearly 32 man-years of sampling, have been analyzed by transmission electron microscopy. The buildings that were surveyed were the subject of litigation related to suits alleging the general building occupants were exposed to a potential health hazard as a result the presence of asbestos-containing materials (ACM). The average concentration of all airborne asbestos structures was 0.01structures/ml (s/ml) and the average concentration of airborne asbestos > or = 5microm long was 0.00012fibers/ml (f/ml). For all samples, 99.9% of the samples were <0.01 f/ml for fibers longer than 5microm; no building averaged above 0.004f/ml for fibers longer than 5microm. No asbestos was detected in 27% of the buildings and in 90% of the buildings no asbestos was detected that would have been seen optically (> or = 5microm long and > or = 0.25microm wide). Background outdoor concentrations have been reported at 0.0003f/ml > or = 5microm. These results indicate that in-place ACM does not result in elevated airborne asbestos in building atmospheres approaching regulatory levels and that it does not result in a significantly increased risk to building occupants.

  16. Fuel Dependence of Benzene Pathways

    SciTech Connect

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

    2008-07-14

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

  17. Spatial and temporal variations in atmospheric VOCs, NO2, SO2, and O3 concentrations at a heavily industrialized region in Western Turkey, and assessment of the carcinogenic risk levels of benzene

    NASA Astrophysics Data System (ADS)

    Civan, Mihriban Yılmaz; Elbir, Tolga; Seyfioglu, Remzi; Kuntasal, Öznur Oğuz; Bayram, Abdurrahman; Doğan, Güray; Yurdakul, Sema; Andiç, Özgün; Müezzinoğlu, Aysen; Sofuoglu, Sait C.; Pekey, Hakan; Pekey, Beyhan; Bozlaker, Ayse; Odabasi, Mustafa; Tuncel, Gürdal

    2015-02-01

    Ambient concentrations of volatile organic compounds (VOCs), nitrogen dioxide (NO2), sulphur dioxide (SO2) and ground-level ozone (O3) were measured at 55 locations around a densely populated industrial zone, hosting a petrochemical complex (Petkim), a petroleum refinery (Tupras), ship-dismantling facilities, several iron and steel plants, and a gas-fired power plant. Five passive sampling campaigns were performed covering summer and winter seasons of 2005 and 2007. Elevated concentrations of VOCs, NO2 and SO2 around the refinery, petrochemical complex and roads indicated that industrial activities and vehicular emissions are the main sources of these pollutants in the region. Ozone concentrations were low at the industrial zone and settlement areas, but high in rural stations downwind from these sources due to NO distillation. The United States Environmental Protection Agency's positive matrix factorization receptor model (EPA PMF) was employed to apportion ambient concentrations of VOCs into six factors, which were associated with emissions sources. Traffic was found to be highest contributor to measured ∑VOCs concentrations, followed by the Petkim and Tupras. Median cancer risk due to benzene inhalation calculated using a Monte Carlo simulation was approximately 4 per-one-million population, which exceeded the U.S. EPA benchmark of 1 per one million. Petkim, Tupras and traffic emissions were the major sources of cancer risk due to benzene inhalation in the Aliaga airshed. Relative contributions of these two source groups changes significantly from one location to another, demonstrating the limitation of determining source contributions and calculating health risk using data from one or two permanent stations in an industrial area.

  18. Law and regulation of benzene.

    PubMed Central

    Feitshans, I L

    1989-01-01

    OSHA has created final benzene regulations after extensive rulemakings on two occasions, 1978 and 1987. These standards have been the subject of extensive litigation for nearly 20 years. This article examines in detail the conceptual underpinnings of the Benzene Case, (which was decided by the U.S. Supreme Court in 1980) in light of U.S. administrative law precedents that have set limits upon administrative discretion under the test for "substantial evidence" and the "hard look doctrine." This article also addresses recent developments in the wake of the Benzene Case and their implications for benzene regulations following the "significant risk" doctrine in that case. This article briefly describes other national, regional, and international laws governing the use of benzene. This article concludes that the revisions of the benzene regulation and subsequent rulemaking provide substantial evidence of scientific underpinnings for regulatory action and that laws from other nations reflect an international consensus that occupational exposure to benzene is a proper subject of regulation. Such regulations and policies are therefore likely to withstand scrutiny and remain enforceable as widely accepted norms. PMID:2792048

  19. Oxidative DNA damage and influence of genetic polymorphisms among urban and rural schoolchildren exposed to benzene.

    PubMed

    Buthbumrung, Nantaporn; Mahidol, Chulabhorn; Navasumrit, Panida; Promvijit, Jeerawan; Hunsonti, Potchanee; Autrup, Herman; Ruchirawat, Mathuros

    2008-04-15

    Traffic related urban air pollution is a major environmental health problem in many large cities. Children living in urban areas are exposed to benzene and other toxic pollutants simultaneously on a regular basis. Assessment of benzene exposure and oxidative DNA damage in schoolchildren in Bangkok compared with the rural schoolchildren was studied through the use of biomarkers. Benzene levels in ambient air at the roadside adjacent to Bangkok schools was 3.95-fold greater than that of rural school areas. Personal exposure to benzene in Bangkok schoolchildren was 3.04-fold higher than that in the rural schoolchildren. Blood benzene, urinary benzene and urinary muconic acid (MA) levels were significantly higher in the Bangkok schoolchildren. A significantly higher level of 8-hydroxy-2'-deoxyguanosine (8-OHdG) in leukocytes and in urine was found in Bangkok children than in the rural children. There was a significant correlation between individual benzene exposure level and blood benzene (rs=0.193, P<0.05), urinary benzene (rs=0.298, P<0.05), urinary MA (rs=0.348, P<0.01), and 8-OHdG in leukocyte (rs=0.130, P<0.05). In addition, a significant correlation between urinary MA and 8-OHdG in leukocytes (rs=0.241, P<0.05) was also found. Polymorphisms of various xenobiotic metabolizing genes responsible for susceptibility to benzene toxicity have been studied; however only the GSTM1 genotypes had a significant effect on urinary MA excretion. Our data indicates that children living in the areas of high traffic density are exposed to a higher level of benzene than those living in rural areas. Exposure to higher level of benzene in urban children may contribute to oxidative DNA damage, suggesting an increased health risk from traffic benzene emission.

  20. [Index assessment of airborne VOCs pollution in automobile for transporting passengers].

    PubMed

    Chen, Xiao-Kai; Cheng, He-Ming; Luo, Hui-Long

    2013-12-01

    Car for transporting passenger is the most common means of transport and in-car airborne volatile organic compounds (VOCs) cause harm to health. In order to analyze the pollution levels of benzene, toluene, ethylbenzene, xylenes, styrene and TVOC, index evaluation method was used according to the domestic and international standards of indoor and in-car air quality (IAQ). For Chinese GB/T 18883-2002 IAQ Standard, GB/T 17729-2009 Hygienic Standard for the Air Quality inside Long Distance Coach, GB/T 27630-2011 Guideline for Air Quality Assessment of Passenger Car, IAQ standard of South Korea, Norway, Japan and Germany, the heaviest pollution of VOCs in passenger car was TVOC, TVOC, benzene, benzene, TVOC, toluene and TVOC, respectively, the average pollution grade of automotive IAQ was median pollution, median pollution, clean, light pollution, median pollution, clean and heavy pollution, respectively. Index evaluation can effectively analyze vehicular interior air quality, and the result has a significant difference with different standards; German standard is the most stringent, while Chinese GB/T 18883-2002 standard is the relatively stringent and GB/T 27630-2011 is the most relaxed.

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

    SciTech Connect

    Sweeney, Lynn C.

    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

  2. Aryl hydrocarbon receptor mediates benzene-induced hematotoxicity.

    PubMed

    Yoon, Byung-Il; Hirabayashi, Yoko; Kawasaki, Yasushi; Kodama, Yukio; Kaneko, Toyozo; Kanno, Jun; Kim, Dae-Yong; Fujii-Kuriyama, Yoshiaki; Inoue, Tohru

    2002-11-01

    Benzene can induce hematotoxicity and leukemia in humans and mice. Since a review of the literature shows that the CYP2E1 knockout mouse is not known to possess any benzene toxicity, the metabolism of benzene by CYP2E1 in the liver is regarded to be prerequisite for its cytotoxicity and genotoxicity, although the mechanism is not fully understood yet. Because it was found some years ago that benzene was also a substrate for CYP1A1, we investigated the involvement of the aryl hydrocarbon receptor (AhR) in benzene hematotoxicity using AhR wild-type (AhR(+/+)), heterozygous (AhR(+/-)), and homozygous (AhR(-/-)) male mice. Interestingly, following a 2-week inhalation of 300 ppm benzene (a potent dose for leukemogenicity), no hematotoxicity was induced in AhR(-/-) mice. Further, there were no changes in cellularity of peripheral blood and bone marrow (BM), nor in levels of granulocyte-macrophage colony-forming units in BM. This lack of hematotoxicity was associated with the lack of p21 overexpression, which was regularly seen in the wild-type mice following benzene inhalation. Combined treatment with two major benzene metabolites, phenol and hydroquinone, induced hemopoietic toxicity, although it was not known whether this happened due to a surprising lack of expression of CYP2E1 by AhR knockout, or due to a lack of other AhR-mediated CYP enzymes, including 1A1 (i.e., a possible alternative pathway of benzene metabolism). The former possibility, evaluated in the present study, failed to show a significant relationship between AhR and the expression of CYP2E1. Furthermore, a subsequent evaluation of AhR expression after benzene inhalation tended to show higher but less significant expression in the liver, and none in the BM, compared with sham control. Although this study failed to identify the more likely of the above-mentioned two possibilities, the study using AhR knockout mice on benzene inhalation presents the unique possibility that the benzene toxicity may be

  3. Process for the preparation of ethyl benzene

    DOEpatents

    Smith, L.A. Jr.; Arganbright, R.P.; Hearn, D.

    1995-12-19

    Ethyl benzene is produced in a catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 50 C to 300 C, using as the catalyst a mole sieve characterized as acidic by feeding ethylene to the catalyst bed while benzene is conveniently added through the reflux to result in a molar excess present in the reactor to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene and diethyl benzene in the bottoms. The bottoms are fractionated, the ethyl benzene recovered and the bottoms are contacted with benzene in the liquid phase in a fixed bed straight pass reactor under conditions to transalkylate the benzene thereby converting most of the diethyl benzene to ethyl benzene which is again separated and recovered. 2 figs.

  4. Process for the preparation of ethyl benzene

    DOEpatents

    Smith, Jr., Lawrence A.; Arganbright, Robert P.; Hearn, Dennis

    1995-01-01

    Ethyl benzene is produced in a catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 50.degree. C. to 300.degree. C., using as the catalyst a mole sieve characterized as acidic by feeding ethylene to the catalyst bed while benzene is conveniently added through the reflux to result in a molar excess present in the reactor to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene and diethyl benzene in the bottoms. The bottoms are fractionated, the ethyl benzene recovered and the bottoms are contacted with benzene in the liquid phase in a fixed bed straight pass reactor under conditions to transalkylate the benzene thereby converting most of the diethyl benzene to ethyl benzene which is again separated and recovered.

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

    NASA Astrophysics Data System (ADS)

    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.

  6. Phase II metabolism of benzene.

    PubMed Central

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

    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 glucuronide. Pretreatment of animals with 3-methylcholantrene (3-MC) markedly increased PH glucuronide formation while PH sulfate formation was decreased. Likewise, V79 cells transfected with the 3-MC-inducible rat UGT1.6 cDNA showed a considerable rate of PH and HQ glucuronidation. In addition to inducing glucuronidation of phenols, 3-MC treatment (reported to protect rats from the myelotoxicity of benzene) resulted in a decrease of hepatic CYP2E1. In contrast, pretreatment of rats with the CYP2E1-inducer isopropanol strongly enhanced benzene metabolism and the formation of phenolic metabolites. Mouse hepatocytes formed much higher amounts of HQ than rat hepatocytes and considerable amounts of 1,2,4-trihydroxybenzene (THB) sulfate and HQ sulfate. In conclusion, the protective effect of 3-MC in rats is probably due to a shift from the labile PH sulfate to the more stable PH glucuronide, and to a decrease in hepatic CYP2E1. The higher susceptibility of mice toward benzene may be related to the high rate of formation of the myelotoxic metabolite HQ and the semistable phase II metabolites HQ sulfate and THB sulfate. Images Figure 4. PMID:9118891

  7. Estimating individual-level exposure to airborne polycyclic aromatic hydrocarbons throughout the gestational period based on personal, indoor, and outdoor monitoring

    SciTech Connect

    Choi, H.; Perera, F.; Pac, A.; Wang, L.; Flak, E.; Mroz, E.; Jacek, R.; Chai-Onn, T.; Jedrychowski, W.; Masters, E.; Camann, D.; Spengler, J.

    2008-11-15

    Current understanding on health effects of long-term polycyclic aromatic hydrocarbon (PAH) exposure is limited by lack of data on time-varying nature of the pollutants at an individual level. In a cohort of pregnant women in Krakow, Poland, we examined the contribution of temporal, spatial, and behavioral factors to prenatal exposure to airborne PAHs within each trimester and developed a predictive model of PAH exposure over the entire gestational period. The observed personal, indoor, and outdoor B(a)P levels we observed in Krakow far exceed the recommended Swedish guideline value for B(a)P of 0.1 ng/m{sup 3}. Based on simultaneously monitored levels, the outdoor PAH level alone accounts for 93% of total variability in personal exposure during the heating season. Living near the Krakow bus depot, a crossroad, and the city, center and time spent outdoors or commuting were not associated with higher personal exposure. During the nonheating season only, a 1-hr increase in environmental tobacco smoke (ETS) exposure was associated with a 10-16% increase in personal exposure to the nine measured PAHs. A 1{degree}C decrease in ambient temperature was associated with a 3-5% increase in exposure to benz(a)anthracene, benzo(k)fluoranthene, and dibenz(a,h)anthracene, after accounting for the outdoor concentration. A random effects model demonstrated that mean personal exposure at a given gestational period depends on the season, residence location, and ETS. Considering that most women reported spending < 3 hr/day outdoors, most women in the study were exposed to outdoor-originating PAHs within the indoor setting. Cross-sectional, longitudinal monitoring supplemented with questionnaire data allowed development of a gestation-length model of individual-level exposure with high precision and validity.

  8. Determination of sound types and source levels of airborne vocalizations by California sea lions, Zalophus californianus, in rehabilitation at the Marine Mammal Center in Sausalito, California

    NASA Astrophysics Data System (ADS)

    Schwalm, Afton Leigh

    California sea lions (Zalophus californianus) are a highly popular and easily recognized marine mammal in zoos, aquariums, circuses, and often seen by ocean visitors. They are highly vocal and gregarious on land. Surprisingly, little research has been performed on the vocalization types, source levels, acoustic properties, and functions of airborne sounds used by California sea lions. This research on airborne vocalizations of California sea lions will advance the understanding of this aspect of California sea lions communication, as well as examine the relationship between health condition and acoustic behavior. Using a PhillipsRTM digital recorder with attached microphone and a calibrated RadioShackRTM sound pressure level meter, acoustical data were recorded opportunistically on California sea lions during rehabilitation at The Marine Mammal Center in Sausalito, CA. Vocalizations were analyzed using frequency, time, and amplitude variables with Raven Pro: Interactive Sound Analysis Software Version 1.4 (The Cornell Lab of Ornithology, Ithaca, NY). Five frequency, three time, and four amplitude variables were analyzed for each vocalization. Differences in frequency, time, and amplitude variables were not significant by sex. The older California sea lion group produced vocalizations that were significantly lower in four frequency variables, significantly longer in two time variables, significantly higher in calibrated maximum and minimum amplitude variables, and significantly lower in frequency at maximum and minimum amplitude compared with pups. Six call types were identified: bark, goat, growl/grumble, bark/grumble, bark/growl, and grumble/moan. The growl/grumble call was higher in dominant beginning, ending, and minimum frequency, as well as in the frequency at maximum amplitude compared with the bark, goat, bark/grumble calls in the first versus last vocalization sample. The goat call was significantly higher in first harmonic interval than any other call type

  9. Airborne asbestos in public buildings

    SciTech Connect

    Chesson, J.; Hatfield, J.; Schultz, B.; Dutrow, E.; Blake, J. )

    1990-02-01

    The U.S. Environmental Protection Agency sampled air in 49 government-owned buildings (six buildings with no asbestos-containing material, six buildings with asbestos-containing material in generally good condition, and 37 buildings with damaged asbestos-containing material). This is the most comprehensive study to date of airborne asbestos levels in U.S. public buildings during normal building activities. The air outside each building was also sampled. Air samples were analyzed by transmission electron microscopy using a direct transfer preparation technique. The results show an increasing trend in average airborne asbestos levels; outdoor levels are lowest and levels in buildings with damaged asbestos-containing material are highest. However, the measured levels and the differences between indoors and outdoors and between building categories are small in absolute magnitude. Comparable studies from Canada and the UK, although differing in their estimated concentrations, also conclude that while airborne asbestos levels may be elevated in buildings that contain asbestos, levels are generally low. This conclusion does not eliminate the possibility of higher airborne asbestos levels during maintenance or renovation that disturbs the asbestos-containing material.

  10. Contribution of traffic emissions to indoor airborne VOCs

    SciTech Connect

    Otson, R.; Williams, D.T.; Fellin, P.

    1998-12-31

    The contribution of nearby vehicle traffic to indoor airborne volatile organic compound levels and to personal exposures was examined to determine the importance of this source. Indoor and outdoor levels of selected VOCs, aldehydes, ketones, and ethanol were measured at 10 homes in Toronto, on sidewalks near the traffic source, indoors and in the backyards or balconies of apartments (outdoors). Concurrently, air exchange rates were measured at each home with a perfluorocarbon tracer method. All the residences were within 1 km of urban intersections with traffic counts of more than 20,000 vehicles per day. Average concentrations of hexane, 1,3-butadiene, toluene, benzene and propionaldehyde decreased in the order: street level > indoor > outdoor. These compounds occur in vehicle emissions, and the contribution of outdoor to indoor concentrations ranged from 24 to 88 % suggesting that traffic emissions contributed to indoor pollutant level through the process of air exchange. For other compounds different trends were observed. Indoors concentrations were greater than outdoors for ethylacetate, tetrachlorethane, pinene, limonene, 1,4-dichlorobenzene, naphthalene, formaldehyde, acetaldehyde and ethanol, for example. These compounds are common in consumer products, and the contribution of outdoor to indoor concentrations ranged from 2 to 44%. The differences in street and backyard (outdoor) concentrations for some compounds were large due to the presence of nearby vehicles at street level sampling sites, indicating that the impact of traffic on human exposures (pedestrians on sidewalks and occupants of vehicles) is potentially large, compared to the impact of general background urban air pollutants.

  11. ITP Filtrate Benzene Removal Alternatives

    SciTech Connect

    Dworjanyn, L.O.

    1993-05-21

    Existing ITP filtrate hold tanks may provide sufficient capacity and residence time to strip dissolved benzene from the incoming filtrate using nitrogen sparging in the bottom of the old tanks. This is based on equilibrium supported by late Wash test data using aged washed slurry. Theoretical considerations indicate that benzene stripping will be more difficult from the ITP unwashed high salt filtrates due to reduced mass transfer. Therefore experimental sparging data is needed to quantify the theoretical effects.Foaming limits which dictate allowable sparging rate will also have to be established. Sparging in the hold tanks will require installation of sintered metal spargers, and possibly stirrers and foam monitoring/disengagement equipment. The most critical sparging needs are at the start of the precipitation/concentration cycle, when the filtrate flux rate is the highest,and at the end of wash cycle where Henry`s equilibrium constant falls off,requiring more gas to sparge the dissolved benzene. With adequate recycle (for proper distribution) or sparging in the old tanks, the 30 inch column could be used for the complete ITP process. A courser packing would reduce back pressure while enabling benzene stripping. The Late Wash Tests indicate adequate benzene stripping even at reduced gas flow. This will require experimental verification under ITP conditions. Using the 30 in. column vs 18 in. during the wash cycle will enhance stripping without need for additional sparging provided the minimum flow requirements are met.

  12. Benzene metabolism in rodents at doses relevant to human exposure from urban air.

    PubMed

    Turteltaub, Kenneth W; Mani, Chitra

    2003-02-01

    Benzene is both an environmental pollutant and a component of cigarette smoke, gasoline, and automotive emissions. Although occupational exposure to benzene has been shown to cause blood disorders and cancer in humans, the potential health effects resulting from exposure to low levels of benzene are not known. The goals of this project were to determine how well benzene is metabolized and to assess its binding to macromolecules in rodents at doses more closely mimicking human environmental exposure. To determine whether genotoxic metabolites of benzene are produced at environmental exposure levels. various doses of 14C-benzene were given intraperitoneally to male B6C3F1 mice at doses from 5 ng/kg to 500 mg/kg body weight. Samples of urine, plasma, liver, and bone marrow were taken at selected times up to 48 hours after exposure. Individual benzene metabolites in the samples were measured by accelerator mass spectrometry (AMS*). Metabolites were quantified by determining the area under the curve (AUC) for 24 to 48 hours. The major metabolites found in urine were an unidentified radiolabeled metabolite. phenyl sulfate, phenyl glucuronide. and muconic acid (an indicator of muconaldehyde formation). The major metabolites found in plasma, liver, and bone marrow samples were muconic acid and hydroquinone. Only liver showed a dose response for hydroquinone and muconic acid. The kinetics of both DNA and protein adduct formation were assessed over 48 hours at a 14C-benzene dose of 5 microg/kg body weight. A dose-response study was then conducted using 14C-benzene doses from 5 ng/kg to 500 mg/kg body weight in B6C3F1 mice. Adduct levels were determined by AMS in liver and bone marrow. DNA and protein adducts in liver reached maximum levels 30 minutes after benzene administration, whereas those in bone marrow reached maximum levels after six hours. Both protein and DNA adduct AUCs were greater in bone marrow than in liver. Dose-response assessments at both 1 and 12 hours

  13. Contribution of tobacco smoke to environmental benzene exposure in Germany

    SciTech Connect

    Scherer, G.; Ruppert, T.; Daube, H.

    1995-12-31

    The concentrations of environmental tobacco smoke (ETS) constituents including benzene were measured in the living rooms of 10 nonsmoking households and 20 households with at least one smoker situated in the city and suburbs of Munich. In the city, the median benzene levels during the evening, when all household members were at home, were 8.1 and 10.4 {mu}g/m{sup 3} in nonsmoking and smoking homes, respectively. The corresponding levels of 3.5 and 4.6 {mu}g/m{sup 3} were considerably lower in the suburbs. Median time-integrated 1-week benzene concentrations in the city were 10.6 {mu}g/m{sup 3} in nonsmoking homes and 13.1 {mu}g/m{sup 3} in smoking homes. In the suburbs, the corresponding values were 3.2 and 5.6 {mu}g/m{sup 3}. No difference was found between smoking and nonsmoking households located either in the city or in the suburbs. There was no statistically significant difference between benzene exposure of non-smokers in smoking and nonsmoking homes. Nonsmokers living in nonsmoking households in the city had significantly higher exposure to benzene compared to their counterparts living in the suburban. Nonsmokers from all households with smokers were significantly more exposed to benzene than nonsmokers living in the nonsmoking households (personal samplers: 13.2 vs. 7.0 {mu}g/m{sup 3}, p < 0.05; benzene in exhalate: 2.6 vs. 1.8 {mu}g/m{sup 3}, p < 0.01; trans-muconic acid excretion in urine: 73 vs. 62 {mu}g/g creatinine), but the contribution of ETS to the total benzene exposure was relatively low compared to that from other sources. Analysis of variance showed that at most 15% of the benzene exposure of nonsmokers living in smoking homes was attributable to ETS. For nonsmokers living in nonsmoking households benzene exposure from ETS was insignificant.

  14. Hematotoxicity and concentration-dependent conjugation of phenol in mice following inhalation exposure to benzene.

    PubMed

    Wells, M S; Nerland, D E

    1991-04-01

    Benzene is metabolized to one or more hematotoxic species. Saturation of benzene metabolism could limit the production of toxic species. Saturation of phase II enzymes involved in the conjugation of the phenolic metabolites of benzene also could affect the hematotoxicity of benzene. To investigate the latter possibility, we exposed male Swiss mice, via the inhalation route, to various concentrations of benzene for 6 h per day for 5 days. Following termination of the final exposure the mice were killed and the levels of phenylsulfate and phenylglucuronide in the blood determined. Spleen weights were recorded and the number of white blood cells counted. At low benzene exposure concentrations phenylsulfate is the major conjugated form of phenol in the blood. At high exposure concentrations, phenylglucuronide is the predominant species. The reductions in spleen weight and white blood cell numbers correlated with the concentration of phenylsulfate in the blood, but are most probably not causally related.

  15. Modeling theta-theta Interactions with the Effective Fragment Potential Method: The Benzene Dimer and Substituents

    SciTech Connect

    Toni Smithl; Lyudmila V. Slipchenko; Mark S. Gordon

    2008-02-27

    This study compares the results of the general effective fragment potential (EFP2) method to the results of a previous combined coupled cluster with single, double, and perturbative triple excitations [CCSD(T)] and symmetry-adapted perturbation theory (SAPT) study [Sinnokrot and Sherrill, J. Am. Chem. Soc., 2004, 126, 7690] on substituent effects in {pi}-{pi} interactions. EFP2 is found to accurately model the binding energies of the benzene-benzene, benzene-phenol, benzene-toluene, benzene-fluorobenzene, and benzene-benzonitrile dimers, as compared with high-level methods [Sinnokrot and Sherrill, J. Am. Chem. Soc., 2004, 126, 7690], but at a fraction of the computational cost of CCSD(T). In addition, an EFP-based Monte Carlo/simulated annealing study was undertaken to examine the potential energy surface of the substituted dimers.

  16. Rapid and Sustainable Detoxication of Airborne Pollutants by Broccoli Sprout Beverage: Results of a Randomized Clinical Trial in China

    PubMed Central

    Wang, Jin-Bing; Kensler, Kevin H.; Jacobson, Lisa P.; Muñoz, Alvaro; Johnson, Jamie L.; Groopman, John D.; Fahey, Jed W.; Talalay, Paul; Zhu, Jian; Chen, Tao-Yang; Qian, Geng-Sun; Carmella, Steven G.; Hecht, Stephen S.; Kensler, Thomas W.

    2014-01-01

    Broccoli sprouts are a convenient and rich source of the glucosinolate, glucoraphanin, which can generate the chemopreventive agent, sulforaphane, an inducer of glutathione S-transferases (GSTs) and other cytoprotective enzymes. A broccoli sprout-derived beverage providing daily doses of 600 μmol glucoraphanin and 40 μmol sulforaphane was evaluated for magnitude and duration of pharmacodynamic action in a 12-week randomized clinical trial. Two hundred and ninety-one study participants were recruited from the rural He-He Township, Qidong, in the Yangtze River delta region of China, an area characterized by exposures to substantial levels of airborne pollutants. Exposure to air pollution has been associated with lung cancer and cardiopulmonary diseases. Urinary excretion of the mercapturic acids of the pollutants, benzene, acrolein, and crotonaldehyde, were measured before and during the intervention using liquid chromatography tandem mass spectrometry. Rapid and sustained, statistically significant (p ≤ 0.01) increases in the levels of excretion of the glutathione-derived conjugates of benzene (61%), acrolein (23%), but not crotonaldehyde were found in those receiving broccoli sprout beverage compared with placebo. Excretion of the benzene-derived mercapturic acid was higher in participants who were GSTT1-positive compared to the null genotype, irrespective of study arm assignment. Measures of sulforaphane metabolites in urine indicated that bioavailability did not decline over the 12-week daily dosing period. Thus, intervention with broccoli sprouts enhances the detoxication of some airborne pollutants and may provide a frugal means to attenuate their associated long-term health risks. PMID:24913818

  17. The effects of meteorological factors on airborne fungal spore concentration in two areas differing in urbanisation level

    NASA Astrophysics Data System (ADS)

    Oliveira, M.; Ribeiro, H.; Delgado, J. L.; Abreu, I.

    2009-01-01

    Although fungal spores are an ever-present component of the atmosphere throughout the year, their concentration oscillates widely. This work aims to establish correlations between fungal spore concentrations in Porto and Amares and meteorological data. The seasonal distribution of fungal spores was studied continuously (2005-2007) using volumetric spore traps. To determine the effect of meteorological factors (temperature, relative humidity and rainfall) on spore concentration, the Spearman rank correlation test was used. In both locations, the most abundant fungal spores were Cladosporium, Agaricus, Agrocybe, Alternaria and Aspergillus/Penicillium, the highest concentrations being found during summer and autumn. In the present study, with the exception of Coprinus and Pleospora, spore concentrations were higher in the rural area than in the urban location. Among the selected spore types, spring-autumn spores ( Coprinus, Didymella, Leptosphaeria and Pleospora) exhibited negative correlations with temperature and positive correlations both with relative humidity and rainfall level. On the contrary, late spring-early summer (Smuts) and summer spores ( Alternaria, Cladosporium, Epicoccum, Ganoderma, Stemphylium and Ustilago) exhibited positive correlations with temperature and negative correlations both with relative humidity and rainfall level. Rust, a frequent spore type during summer, had a positive correlation with temperature. Aspergillus/Penicillium, showed no correlation with the meteorological factors analysed. This knowledge can be useful for agriculture, allowing more efficient and reliable application of pesticides, and for human health, by improving the diagnosis and treatment of respiratory allergic disease.

  18. Exploring the relationship between a ground-based network and airborne CCN spectra observed at the cloud level

    NASA Astrophysics Data System (ADS)

    Corrigan, C.; Roberts, G. C.; Ritchie, J.; Creamean, J.; White, A. B.

    2011-12-01

    Cloud condensation nuclei (CCN) are aerosol particles that participate in the formation of clouds, and consequently, play a significant role in the influence of anthropogenic aerosols on atmospheric processes and climate change. Ultimately, the CCN of the most interest occupy the part of the atmosphere where cloud processes are occurring. A question arises as to whether in-cloud CCN are properly represented by the measurements of CCN at the ground level. While different locations may result in different answers depending upon local meteorology, the data set collected during CalWater 2011 may allow us to answer to what degree the ground-based observations of CCN are sufficient for evaluating cloud micro-physics over California's Central Valley and the lower slopes of the Sierra Nevada Mountains. During CalWater 2011, ground observations were performed at three different altitudes to assess the evolution of cloud-active aerosols as they were transported from sources in California's Central Valley to the lower slopes of the Sierra Nevada Mountains. CCN spectra were collected over a supersaturation range of 0.08 to 0.80%. Results from these data sets show a diurnal cycle with aerosol concentrations increasing during the afternoon and retreating during the night. In addition, a CCN instrument was placed aboard aircraft for several flights and was able to collect vertical profiles that encompassed the altitudes of the ground sites. The flight data shows a large drop in CCN concentration above the boundary layer and suggests the highest altitude ground site at China Wall ( 1540 masl)was sometimes above the Central Valley boundary layer. By using estimates of boundary layer heights over the mid-altitude site at Sugar Pine Dam (1060 masl), the events when the China Wall site is near or above the boundary layer are identified. During these events, the CCN measurements at China Wall best represent in-cloud CCN behavior. The results of this analysis may be applied towards a

  19. The Solubility of Phenylborate Compounds in Benzene

    SciTech Connect

    Eibling, R.E.

    1998-04-01

    The original goal of this scoping study was to determine if the solubility of sodium and potassium tetraphenylborates in benzene was sufficiently large to justify designing and performing kinetic studies on a benzene-phase catalytic reaction.

  20. An analytical program for determination and confirmation of airborne levels of chemical agent in the event of a suspected release

    SciTech Connect

    Paul, D.G.; Jakubowski, E.M.

    1995-12-31

    The Monitoring Branch Laboratory of the US Army Operations Directorate, Chemical Support Division is uniquely outfitted to respond quickly when the need arises to identify and measure atmospheric contamination levels of military unique compounds. Samples collected with a vacuum pump on solid sorbent tubes are initially screened using gas chromatography (GC) and a sulfur/phosphorus specific detector to determine and quantify the presence or absence of contaminants. Positive samples from the first stage of testing are subjected to subsequent analysis with different detectors to confirm genuine positives and eliminate false positives. Subsequent testing provides information during follow-up and site remediation activities through screening of soil and other environmental samples. Monitoring Branch uses Depot Area Air Monitoring Systems (DAAMS) technology in which a sample is collected onto a solid sorbent tube, and subsequently analyzed through thermal desorption of the sample into a gas chromatograph equipped with a simultaneous dual Flame Photometric Detector (FPD) for sulfur and phosphorus detection. Confirmation is accomplished using the same solid sorbent/thermal desorption/GC instrumentation with Atomic Emission Detection to confirm through elemental analysis and Mass Spectrophotometric Detection for structural confirmation. Soil and other environmental samples such as building debris are extracted manually using an organic solvent and analyzed using DAAMS technology and the same variety of detectors.

  1. Physical protection against airborne pathogens and pollutants by a novel animal isolator in a level 3 containment laboratory.

    PubMed Central

    Wathes, C. M.; Johnson, H. E.

    1991-01-01

    A containment laboratory unit for research with aerosols of group 2 pathogenic microorganisms is described. The design criteria are based on current UK guidelines, which imply containment at group 3 level during aerosol production, storage, exposure of animals and sampling. Within the aerosol laboratory, primary containment is provided by a Henderson apparatus operating at a negative pressure to the external environment. Flexible film isolators under negative pressure are used for all hazardous microbiological work, e.g. tissue homogenization, and for housing infected laboratory rodents. A novel feature of the animal isolator is the separate ventilation of each cage, which minimizes the risk of cross-infection by aerosol transmission and ensures a similar environment within each cage. The results of an intentional release of a cloud of non-pathogenic microorganisms are presented to show the effectiveness of the containment barriers. Recommendations are given for the safe operation of a containment unit based upon practical experience. Images Fig. 2 Fig. 3 PMID:1908783

  2. Benzene toxicokinetics in humans: exposure of bone marrow to metabolites.

    PubMed Central

    Watanabe, K H; Bois, F Y; Daisey, J M; Auslander, D M; Spear, R C

    1994-01-01

    A three compartment physiologically based toxicokinetic model was fitted to human data on benzene disposition. Two separate groups of model parameter derivations were obtained, depending on which data sets were being fitted. The model was then used to simulate five environmental or occupational exposures. Predicted values of the total bone marrow exposure to benzene and cumulative quantity of metabolites produced by the bone marrow were generated for each scenario. The relation between cumulative quantity of metabolites produced by the bone marrow and continuous benzene exposure was also investigated in detail for simulated inhalation exposure concentrations ranging from 0.0039 ppm to 150 ppm. At the level of environmental exposures, no dose rate effect was found for either model. The occupational exposures led to only slight dose rate effects. A 32 ppm exposure for 15 minutes predicted consistently higher values than a 1 ppm exposure for eight hours for the total exposure of bone marrow to benzene and the cumulative quantity of metabolites produced by the bone marrow. The general relation between the cumulative quantity of metabolites produced by the bone marrow and the inhalation concentration of benzene is not linear. An inflection point exists in some cases leading to a slightly S shaped curve. At environmental levels (0.0039-10 ppm) the curve bends upward, and it saturates at high experimental exposures (greater than 100 ppm). PMID:8044234

  3. Alterations in leukocyte telomere length in workers occupationally exposed to benzene.

    PubMed

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

    2014-10-01

    Exposure to benzene, a known leukemogen and probable lymphomagen, has been demonstrated to result in oxidative stress, which has previously been associated with altered telomere length (TL). TL specifically has been associated with several health outcomes in epidemiologic studies, including cancer risk, and has been demonstrated to be altered following exposure to a variety of chemical agents. To evaluate the association between benzene exposure and TL, we measured TL by monochrome multiplex quantitative PCR in 43 workers exposed to high levels of benzene and 43 age and sex-matched unexposed workers in Shanghai, China. Benzene exposure levels were monitored using organic vapor passive dosimetry badges before phlebotomy. The median benzene exposure level in exposed workers was 31 ppm. The mean TL in controls, workers exposed to levels of benzene below the median (≤31 ppm), and above the median (>31 ppm) was 1.26 ± 0.17, 1.25 ± 0.16, and 1.37 ± 0.23, respectively. Mean TL was significantly elevated in workers exposed to >31 ppm of benzene compared with controls (P = 0.03). Our findings provide evidence that high levels of occupational benzene exposure are associated with TL. Environ.

  4. Benzene exposure in industries using or manufacturing paint in China--a literature review, 1956-2005.

    PubMed

    Liu, Hong; Liang, Youxin; Bowes, Stephen; Xu, Hongzhi; Zhou, Yimei; Armstrong, Thomas W; Wong, Otto; Schnatter, A R; Fang, Jinbin; Wang, Laiming; Nie, Liping; Fu, Hua; Irons, Richard

    2009-11-01

    A systematic review of the Chinese literature was conducted from 1956 to 2005. The survey included both online and manual searching, as well as expert discussions aimed at providing insight into factors affecting benzene exposure levels in paint/coatings industries. Data extracted from 204 papers included: (1) year of occurrence, (2) type of paint/coatings products, (3) type of industries where the products were used or produced, (4) job titles and work activities, (5) type of literature searched, (6) working conditions whenever data were available, and (7) exposure levels. Most benzene measurements were short-term samples for comparison with the Chinese maximum allowable concentration standard. The accuracy and precision of the sampling and analytical methods were not reported. The distribution of benzene concentrations was tested and found to fit neither normal nor lognormal distributions. Analysis of variance (comparison for more than two groups) and t-test (comparison for two groups) were conducted on Blom-transformed benzene concentration data. The overall median benzene exposure levels were 215, 82, 31, and 6 mg/m(3) during the periods 1956-1978, 1979-1989, 1990-2001, and 2002-2005, respectively. Mean benzene exposure was significantly lower for paint manufacturing than paint spraying. No significant difference was found among paint types and benzene exposure for paint application. Benzene exposure was significantly higher in workplaces judged to have poor ventilation. No significant differences were found in benzene exposure as a function of industry type. Even though substantially lower when compared with levels in the past, recent benzene exposure measurements suggested that many facilities in the paint/coatings industries in China still have benzene concentrations that are above the current China occupational exposure limit for benzene (6 mg/m(3) as a time-weighted average). Benzene concentrations from the present exercise, while not directly supporting

  5. 27 CFR 21.97 - Benzene.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Benzene. 21.97 Section 21... TREASURY ALCOHOL 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...

  6. 27 CFR 21.97 - Benzene.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 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...

  7. 27 CFR 21.97 - Benzene.

    Code of Federal Regulations, 2010 CFR

    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...

  8. 27 CFR 21.97 - Benzene.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 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. 27 CFR 21.97 - Benzene.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Benzene. 21.97 Section 21... TREASURY ALCOHOL 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...

  10. Looking through the haze: evaluating the CALIPSO level 2 aerosol optical depth using airborne high spectral resolution lidar data

    NASA Astrophysics Data System (ADS)

    Rogers, R. R.; Vaughan, M. A.; Hostetler, C. A.; Burton, S. P.; Ferrare, R. A.; Young, S. A.; Hair, J. W.; Obland, M. D.; Harper, D. B.; Cook, A. L.; Winker, D. M.

    2014-06-01

    error contribute to both positive and negative errors in the CALIOP column AOD, including multiple layers in the column of different aerosol types, lidar ratio errors, cloud misclassification, and undetected aerosol layers. The undetected layers were further investigated and we found that the layer detection algorithm works well at night, although undetected aerosols in the free troposphere introduce a mean underestimate of 0.02 in the column AOD in the dataset examined. The decreased SNR during the daytime led to poorer performance of the layer detection. This caused the daytime CALIOP column AOD to be less accurate than during the nighttime because CALIOP frequently does not detect optically thin aerosol layers with AOD < 0.1. Given that the median vertical extent of aerosol detected within any column was 1.6 km during the nighttime and 1.5 km during the daytime we can estimate the minimum extinction detection threshold to be 0.012 km-1 at night and 0.067 km-1 during the daytime in a layer median sense. This extensive validation of level 2 CALIOP aerosol layer optical depth products extends previous validation studies to nighttime lighting conditions and provides independent measurements of the lidar ratio, thus allowing the assessment of the effect on the CALIOP AOD of using inappropriate lidar ratio values in the extinction retrieval.

  11. Looking through the haze: evaluating the CALIPSO level 2 aerosol optical depth using airborne high spectral resolution lidar data

    NASA Astrophysics Data System (ADS)

    Rogers, R. R.; Vaughan, M. A.; Hostetler, C. A.; Burton, S. P.; Ferrare, R. A.; Young, S. A.; Hair, J. W.; Obland, M. D.; Harper, D. B.; Cook, A. L.; Winker, D. M.

    2014-12-01

    error contribute to both positive and negative errors in the CALIOP column AOD, including multiple layers in the column of different aerosol types, lidar ratio errors, cloud misclassification, and undetected aerosol layers. The undetected layers were further investigated and we found that the layer detection algorithm works well at night, although undetected aerosols in the free troposphere introduce a mean underestimate of 0.02 in the column AOD in the data set examined. The decreased signal-to-noise ratio (SNR) during the daytime led to poorer performance of the layer detection. This caused the daytime CALIOP column AOD to be less accurate than during the nighttime, because CALIOP frequently does not detect optically thin aerosol layers with AOD < 0.1. Given that the median vertical extent of aerosol detected within any column was 1.6 km during the nighttime and 1.5 km during the daytime, we can estimate the minimum extinction detection threshold to be 0.012 km-1 at night and 0.067 km-1 during the daytime in a layer median sense. This extensive validation of level 2 CALIOP AOD products extends previous validation studies to nighttime lighting conditions and provides independent measurements of the lidar ratio; thus, allowing the assessment of the effect on the CALIOP AOD of using inappropriate lidar ratio values in the extinction retrieval.

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

    PubMed

    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 <1 p.p.m. This provocative finding motivated the 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

  13. 46 CFR 151.05-2 - Compliance with requirements for tank barges carrying benzene and benzene containing cargoes, or...

    Code of Federal Regulations, 2010 CFR

    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...

  14. 46 CFR 151.05-2 - Compliance with requirements for tank barges carrying benzene and benzene containing cargoes, or...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 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...

  15. 46 CFR 151.05-2 - Compliance with requirements for tank barges carrying benzene and benzene containing cargoes, or...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 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...

  16. 46 CFR 151.05-2 - Compliance with requirements for tank barges carrying benzene and benzene containing cargoes, or...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 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...

  17. 46 CFR 151.05-2 - Compliance with requirements for tank barges carrying benzene and benzene containing cargoes, or...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 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...

  18. Accumulation of chlorinated benzenes in earthworms

    USGS Publications Warehouse

    Beyer, W.N.

    1996-01-01

    Chlorinated benzenes are widespread in the environment. Hexachlorobenzene, pentachlorobenzene and all isomers of dichlorobenzenes, trichlorobenzenes, and tetrachlorobenzenes, have been detected in fish, water, and sediments from the Great Lakes. This paper describes a long-term (26 week) experiment relating the concentrations of chlorinated benzenes in earthworms to 1) the length of exposure, and it describes three 8-week experiments relating concentrations of chlorinated benzenes in earthworms to 2) their concentration in soil 3) the soil organic matter content and, 4) the degree of chlorination. In the 26-week experiment, the concentration of 1,2,4 - trichlorobenzene in earthworms fluctuated only slightly about a mean of 0.63 ppm (Fig. 1). Although a statistically significant decrease can be demonstrated over the test (Pearson correlation coefficient, r = -0.62 p < 0.05), the decrease was minor. Hexachlorobenzene in earthworms showed a cyclical trend that coincided with replacement of the media, and a slight but statistically significant tendency to increase from about 2 to 3 ppm over the 26 weeks (r = 0.55, p < 0.05). Concentrations of both trichlorobenzene and hexachlorobenzene in earthworms increased as the concentrations in the soil increased (Fig. 2), but leveled off at the highest soil concentrations. The most surprising result of this study was the relatively low concentrations in earthworms compared to those in soils. The average concentration of each of the six isomers of trichlorobenzene and tetrachlorobenzene in earthworms was only about 1 ppm (Table 2); the isomeric structure did not affect accumulation. The concentration of organic matter in soil had a prominent effect on hexachlorobenzene concentrations in earthworms (Fig. 3). Hexachlorobenzene concentrations decreased steadily from 9.3 ppm in earthworms kept in soil without any peat moss added to about 1 ppm in soil containing 16 or 32% organic matter.

  19. Webinar: Airborne Data Discovery and Analysis with Toolsets for Airborne Data (TAD)

    Atmospheric Science Data Center

    2016-10-18

    Webinar: Airborne Data Discovery and Analysis with Toolsets for Airborne Data (TAD) Wednesday, October 26, 2016 Join us on ... based on high-level parameter groups, mission, platform and flight data ranges are available. Registration is now open.  Access the full ...

  20. Hydrogen bonding in the benzene-ammonia dimer

    NASA Technical Reports Server (NTRS)

    Rodham, David A.; Suzuki, Sakae; Suenram, Richard D.; Lovas, Frank J.; Dasgupta, Siddharth; Goddard, William A., III; Blake, Geoffrey A.

    1993-01-01

    High-resolution optical and microwave spectra of the gas-phase benzene-ammonia dimer were obtained, showing that the ammonia molecule resides above the benzene plane and undergoes free, or nearly free, internal rotation. To estimate the binding energy (De) and other global properties of the intermolecular potential, theoretical calculations were performed for the benzene-ammonia dimer, using the Gaussian 92 (Fritsch, 1992) program at the MP2/6-31G** level. The predicted De was found to be at the lowest end of the range commonly accepted for hydrogen bonding and considerably below that of C6H6-H2O, consistent with the gas-phase acidities of ammonia and water. The observed geometry greatly resembles the amino-aromatic interaction found naturally in proteins.

  1. Human Benzene Metabolism Following Occupational and Environmental Exposures

    PubMed Central

    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

  2. Ground-level airborne particulate matter near important Portuguese Cultural Heritage sites in high polluted (Lisbon) and low polluted (Evora) urban environments

    NASA Astrophysics Data System (ADS)

    Schiavon, N.; Wagner, F.; Candeias, A.; Kandler, K.; Tobias, L.; Mirao, J.

    2012-04-01

    As part of a wider project on aerosol composition in the Southwestern part of the Iberian peninsula, an intensive field monitoring/sampling/analytical campaign has been conducted in August and December 2011 to assess indoor and outdoor atmospheric aerosol optical and microphysical parameters (Nephelometry), number/mass/size distribution (TEOM, MAAP, OPS) and single particle minero-chemical composition on filter collected samples (VP-SEM+EDS, XRD) at several sheltered and unsheltered locations close to important Cultural Heritage monuments in Evora and Lisbon, Portugal. Sites investigated included the Igreja do S. Francisco in Evora, the Cristo Rei sanctuary, Jeronimos Monastery, and Lisbon Castle in Lisbon. At Cristo Rei measurements at sea level, around 100m and around 180m were carried out in order to determine the vertical profile of the particle size distribution. Measurements were taken at different times of day reflecting changes in atmospheric mixing and air pollution levels. Measurements were also performed near an air quality monitoring station at Avenida de Libertade (the busiest traffic artery in Lisbon city center) during traffic peak hour. One of the aims of the campaign was to determine differences in airborne particulate matter compositions and concentrations between an urban coastal high pollution (Lisbon) and a low pollution (Evora) environments and how these could affect the nature of decay patterns and processes in the building materials of the monuments under investigation. Preliminary results indicate significant differences in particle properties between the 2 cities as well as between indoor and outdoor locations. One interesting result was the detection of considerable amounts of particle of oceanic origin (such as sodium chloride) in the Evora site even at 130 km away from the coast. Despite its relatively unpolluted location, single particle analysis by SEM+EDS at the Evora site reveals the presence of significant numbers of particle of

  3. Effects of inhalation exposure to a binary mixture of benzene and toluene on vitamin a status and humoral and cell-mediated immunity in wild and captive American kestrels.

    PubMed

    Olsgard, Mandy L; Bortolotti, Gary R; Trask, Brenda R; Smits, Judit E G

    2008-01-01

    Benzene and toluene are representative volatile organic compounds (VOC) released during production, storage, and transportation associated with the oil and gas industry and are chemicals of concern, as they are released in greater and possibly more biologically significant concentrations than other compounds. Most studies of air pollution in high oil and gas activity areas have neglected to consider risks to birds, including top-level predators. Birds can be used as highly sensitive monitors of air quality and since the avian respiratory tract is physiologically different from a rodent respiratory tract, effects of gases cannot be safely extrapolated from rodent studies. Wild and captive male American kestrels were exposed for approximately 1 h daily for 28 d to high (rodent lowest-observed-adverse-effect level [LOAEL] of 10 ppm and 80 ppm, respectively) or environmentally relevant (0.1 ppm and 0.8 ppm, respectively) levels of benzene and toluene. Altered immune responses characteristic of those seen in mammalian exposures were evident in kestrels. A decreased cell-mediated immunity, measured by delayed-type hypersensitivity testing, was evident in all exposed birds. There was no effect on humoral immunity. Plasma retinol levels as measured by high-performance liquid chromatography (HPLC) analysis were decreased in wild and captive kestrels exposed to the rodent LOAEL for combined benzene and toluene. This study indicates that American kestrels are sensitive to combined benzene and toluene. The study also illustrates the need for reference concentrations for airborne pollutants to be calculated, including sensitive endpoints specific to birds. Based on these findings, future studies need to include immune endpoints to determine the possible increased susceptibility of birds to inhaled toxicants.

  4. Bacterial dehalorespiration with chlorinated benzenes.

    PubMed

    Adrian, L; Szewzyk, U; Wecke, J; Görisch, H

    2000-11-30

    Chlorobenzenes are toxic, highly persistent and ubiquitously distributed environmental contaminants that accumulate in the food chain. The only known microbial transformation of 1,2,3,5-tetrachlorobenzene (TeCB) and higher chlorinated benzenes is the reductive dechlorination to lower chlorinated benzenes under anaerobic conditions observed with mixed bacterial cultures. The lower chlorinated benzenes can subsequently be mineralized by aerobic bacteria. Here we describe the isolation of the oxygen-sensitive strain CBDB1, a pure culture capable of reductive dechlorination of chlorobenzenes. Strain CBDB1 is a highly specialized bacterium that stoichiometrically dechlorinates 1,2,3-trichlorobenzene (TCB), 1,2,4-TCB, 1,2,3,4-TeCB, 1,2,3,5-TeCB and 1,2,4,5-TeCB to dichlorobenzenes or 1,3,5-TCB. The presence of chlorobenzene as an electron acceptor and hydrogen as an electron donor is essential for growth, and indicates that strain CBDB1 meets its energy needs by a dehalorespiratory process. According to their 16S rRNA gene sequences, strain CBDB1, Dehalococcoides ethenogenes and several uncultivated bacteria form a new bacterial cluster, of which strain CBDB1 is the first, so far, to thrive on a purely synthetic medium.

  5. Bioremediation of chlorinated benzene compounds

    SciTech Connect

    Peck, P.C.; Rhodes, S.H.; Guerin, T.F.

    1995-12-31

    In early 1994, investigations at a pharmaceutical manufacturing site revealed extensive areas of soil contaminated with chlorinated benzenes. The soil was a heavy clay and contained chlorobenzene (CB), 1,2-dichlorobenzene (referred to in this paper as DCB), and small amounts of 1,3- and 1,4-dichlorobenzene and other solvents. The soil was bioremediated in a pilot-scale treatment using an ex situ process with various inorganic and organic amendments. Approximately 90% of the DCB mass present in the soil was removed over a period of 2 to 3 weeks. Up to 100-fold increases in both total heterotrophs and specific degraders were observed. Residual concentrations of chlorinated benzenes were generally below detection limits. Adding organic matter did not appear to significantly enhance the treatment efficiency. Mass balance calculations applied to the treatment indicated that less than 5% of the chlorinated benzenes were removed by volatilization. Evidence was obtained that approximately 90% of the DCB was removed by biodegradation in these pilot-scale trials. Laboratory shake flask trials were conducted which confirmed that the soils in the pilot-scale treatment contained microorganisms capable of mineralizing CB and DCB.

  6. Assessment of human exposure to benzene through foods from the Belgian market.

    PubMed

    Medeiros Vinci, Raquel; Jacxsens, Liesbeth; Van Loco, Joris; Matsiko, Eric; Lachat, Carl; de Schaetzen, Thibault; Canfyn, Michael; Van Overmeire, Ilse; Kolsteren, Patrick; De Meulenaer, Bruno

    2012-08-01

    Benzene is a volatile organic compound known to be carcinogenic to humans (Group 1) and may be present in food. In the present study, 455 food samples from the Belgian market were analyzed for benzene contents and some possible sources of its occurrence in the foodstuffs were evaluated. Benzene was found above the level of detection in 58% of analyzed samples with the highest contents found in processed foods such as smoked and canned fish, and foods which contained these as ingredients (up to 76.21 μg kg(-1)). Unprocessed foods such as raw meat, fish, and eggs contained much lower concentrations of benzene. Using the benzene concentrations in food, a quantitative dietary exposure assessment of benzene intake was conducted on a national representative sample of the Belgian population over 15 years of age. The mean benzene intake for all foods was 0.020 μg kg bw d(-1) according to a probabilistic analysis. These values are below the minimum risk level for oral chronic exposure to benzene (0.5 μg kg bw d(-1)). PMID:22483726

  7. Effects of benzene inhalation on lymphocyte subpopulations and immune response in mice.

    PubMed

    Aoyama, K

    1986-08-01

    To clarify the immunotoxicity of benzene, the effects of benzene inhalation on T and B lymphocytes and immune responses in mice were examined. BALB/c male mice were exposed to 50 or 200 ppm benzene vapor, 6 hr/day for 7 or 14 consecutive days. T and B lymphocytes, in blood and spleen, were detected by the cytotoxicity assay with anti-Thy-1.2 monoclonal antibody and the membrane immunofluorescence test with anti-immunoglobulin antibody, respectively. Humoral immune response to sheep red blood cells was determined by the hemolytic plaque-forming cell assay. Cell-mediated immune response was measured by contact sensitivity (CS) to picryl chloride. The activity of suppressor cells was evaluated in spleen by the suppressive effect on passive transfer of CS. The ratio and absolute number of T and B lymphocytes in blood and spleen were depressed after a 7-day exposure at 50 ppm benzene. The depression of B lymphocytes was dose dependent and more intense than that of T lymphocytes. The ability to form antibodies was suppressed by benzene at all exposure levels, but the CS response was resistant to benzene inhalation and rather enhanced at 200 ppm exposure for 14 days. The activity of suppressor cells could not be detected at this dose level. These data show that benzene inhalation effects on humoral and cell-mediated immune responses are a result of the selective toxicity of benzene to B lymphocytes and suppressor T cells.

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

    NASA Astrophysics Data System (ADS)

    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.

  9. Assessment of human exposure to benzene through foods from the Belgian market.

    PubMed

    Medeiros Vinci, Raquel; Jacxsens, Liesbeth; Van Loco, Joris; Matsiko, Eric; Lachat, Carl; de Schaetzen, Thibault; Canfyn, Michael; Van Overmeire, Ilse; Kolsteren, Patrick; De Meulenaer, Bruno

    2012-08-01

    Benzene is a volatile organic compound known to be carcinogenic to humans (Group 1) and may be present in food. In the present study, 455 food samples from the Belgian market were analyzed for benzene contents and some possible sources of its occurrence in the foodstuffs were evaluated. Benzene was found above the level of detection in 58% of analyzed samples with the highest contents found in processed foods such as smoked and canned fish, and foods which contained these as ingredients (up to 76.21 μg kg(-1)). Unprocessed foods such as raw meat, fish, and eggs contained much lower concentrations of benzene. Using the benzene concentrations in food, a quantitative dietary exposure assessment of benzene intake was conducted on a national representative sample of the Belgian population over 15 years of age. The mean benzene intake for all foods was 0.020 μg kg bw d(-1) according to a probabilistic analysis. These values are below the minimum risk level for oral chronic exposure to benzene (0.5 μg kg bw d(-1)).

  10. A calibrated human PBPK model for benzene inhalation with urinary bladder and bone marrow compartments.

    PubMed

    Knutsen, Jeffrey S; Kerger, Brent D; Finley, Brent; Paustenbach, Dennis J

    2013-07-01

    A physiologically-based pharmacokinetic (PBPK) model of benzene inhalation based on a recent mouse model was adapted to include bone marrow (target organ) and urinary bladder compartments. Empirical data on human liver microsomal protein levels and linked CYP2E1 activities were incorporated into the model, and metabolite-specific conversion rate parameters were estimated by fitting to human biomonitoring data and adjusting for background levels of urinary metabolites. Human studies of benzene levels in blood and breath, and phenol levels in urine were used to validate the rate of human conversion of benzene to benzene oxide, and urinary benzene metabolites from Chinese benzene worker populations provided model validation for rates of human conversion of benzene to muconic acid (MA) and phenylmercapturic acid (PMA), phenol (PH), catechol (CA), hydroquinone (HQ), and benzenetriol (BT). The calibrated human model reveals that while liver microsomal protein and CYP2E1 activities are lower on average in humans compared to mice, the mouse also shows far lower rates of benzene conversion to MA and PMA, and far higher conversion of benzene to BO/PH, and of BO/PH to CA, HQ, and BT. The model also differed substantially from existing human PBPK models with respect to several metabolic rate parameters of importance to interpreting benzene metabolism and health risks in human populations associated with bone marrow doses. The model provides a new methodological paradigm focused on integrating linked human liver metabolism data and calibration using biomonitoring data, thus allowing for model uncertainty analysis and more rigorous validation.

  11. Benzene toxicity and risk assessment, 1972-1992: implications for future regulation.

    PubMed Central

    Paustenbach, D J; Bass, R D; Price, P

    1993-01-01

    Acute and chronic exposure to benzene vapors poses a number of health hazards to humans. To evaluate the probability that a specific degree of exposure will produce an adverse effect, risk assessment methods must be used. This paper reviews much of the published information and evaluates the various risk assessments for benzene that have been conducted over the past 20 years. There is sufficient evidence that chronic exposure to relatively high concentrations of benzene can produce an increased incidence of acute myelogenous leukemia (AML). Some studies have indicated that benzene may cause other leukemias, but due to the inconsistency of results, the evidence is not conclusive. To predict the leukemogenic risk for humans exposed to much lower doses of benzene than those observed in most epidemiology studies, a model must be used. Although several models could yield plausible results, to date most risk assessments have used the linear-quadratic or conditional logistic models. These appear to be the most appropriate ones for providing the cancer risk for airborne concentrations of 1 ppb to 10 ppm, the range most often observed in the community and workplace. Of the seven major epidemiology studies that have been conducted, there is a consensus that the Pliofilm cohort (rubber workers) is the best one for estimating the cancer potency because it is the only one with good exposure and incidence of disease data. The current EPA, OSHA, and ACGIH cancer potency estimates for benzene are based largely on this cohort. A retrospective exposure assessment and an analysis of the incidence of disease in these workers were completed in 1991. All of these issues are discussed and the implications evaluated in this paper. The range of benzene exposures to which Americans are commonly exposed and the current regulatory criteria are also presented. PMID:8020442

  12. Benzene toxicity and risk assessment, 1972-1992: Implications for future regulation

    SciTech Connect

    Paustenbach, D.J.; Bass, R.D.; Price, P.

    1993-12-01

    Acute and chronic exposure to benzene vapors poses a number of health hazards to humans. To evaluate the probability that a specific degree of exposure will produce an adverse effect, risk assessment methods must be used. This paper reviews much of the published information and evaluates the various risk assessments for benzene that have been conducted over the past 20 years. There is sufficient evidence that chronic exposure to relatively high concentrations of benzene can produce an increased incidence of acute myelogenous leukemia (AML). Some studies have indicated that benzene may cause other leukemias, but due to the inconsistency of results, the evidence is not conclusive. To predict the leukemogenic risk for humans exposed to much lower doses of benzene than those observed in most epidemiology studies, a model must be used. Although several models could yield plausible results, to date most risk assessments have used the linear-quadratic or conditional logistic models. These appear to be the most appropriate ones for providing the cancer risk for airborne concentrations of 1 ppb to 10 ppm, the range most often observed in the community and workplace. Of the seven major epidemiology studies that have been conducted, there is a consensus that the Pliofilm cohort (rubber workers) is the best one for estimating the cancer potency because it is the only one with good exposure and incidence of disease data. The current EPA, OSHA, and ACGIH cancer potency estimates for benzene are based largely on this cohort. A retrospective exposure assessment and an analysis of the incidence of disease in these workers were completed in 1991. All of these issues are discussed and the implications evaluated in this paper. The range of benzene exposures to which Americans are commonly exposed and the current regulatory criteria are also presented. 268 refs., 3 figs., 13 tabs.

  13. Male mice deficient in microsomal epoxide hydrolase are not susceptible to benzene-induced toxicity.

    PubMed

    Bauer, Alison K; Faiola, Brenda; Abernethy, Diane J; Marchan, Rosemarie; Pluta, Linda J; Wong, Victoria A; Gonzalez, Frank J; Butterworth, Byron E; Borghoff, Susan J; Everitt, Jeffrey I; Recio, Leslie

    2003-04-01

    Enzymes involved in benzene metabolism are likely genetic determinants of benzene-induced toxicity. Polymorphisms in human microsomal epoxide hydrolase (mEH) are associated with an increased risk of developing leukemia, specifically those associated with benzene. This study was designed to investigate the importance of mEH in benzene-induced toxicity. Male and female mEH-deficient (mEH-/-) mice and background mice (129/Sv) were exposed to inhaled benzene (0, 10, 50, or 100 ppm) 5 days/week, 6 h/day, for a two-week duration. Total white blood cell counts and bone marrow cell counts were used to assess hematotoxicity and myelotoxicity. Micronucleated peripheral blood cells were counted to assess genotoxicity, and the p21 mRNA level in bone marrow cells was used as a determinant of the p53-regulated DNA damage response. Male mEH-/- mice did not have any significant hematotoxicity or myelotoxicity at the highest benzene exposure compared to the male 129/Sv mice. Significant hematotoxicity or myelotoxicity did not occur in the female mEH-/- or 129/Sv mice. Male mEH-/- mice were also unresponsive to benzene-induced genotoxicity compared to a significant induction in the male 129/Sv mice. The female mEH-/- and 129/Sv mice were virtually unresponsive to benzene-induced genotoxicity. While p21 mRNA expression was highly induced in male 129/Sv mice after exposure to 100-ppm benzene, no significant alteration was observed in male mEH-/- mice. Likewise, p21 mRNA expression in female mEH-/- mice was not significantly induced upon benzene exposure whereas a significant induction was observed in female 129/Sv mice. Thus mEH appears to be critical in benzene-induced toxicity in male, but not female, mice.

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

    NASA Astrophysics Data System (ADS)

    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.

  15. Ferrokinetics and erythropoiesis in mice after long-term inhalation of benzene.

    PubMed

    Vácha, J; Znojil, V; Seidel, H J; Barthel, E

    1990-01-01

    Ferrokinetics and erythropoiesis were examined in mice exposed for 6 or 7 weeks to an airborne concentration of 300 ppm of benzene, for 6 h per day, and 5 days per week. Ferrokinetic indicators showed only a slightly enhanced production of haeme and erythrocytes in the spleen (133% +/- 18% and 122% +/- 17%, respectively). Production did not change in the femoral marrow; a decline of CFU-C, BFU-E and especially CFU-E (34% +/- 8%) took place there and a shift of cellularity into less mature developmental classes in the erythroblast compartment, without this compartment as a whole being damaged. The erythrocytes produced have an enhanced MCV (109% +/- 0%) and MCH (109% +/- 1%) with an unchanged MCHC; their concentration in blood sank to 87% +/- 1%. The absolute reticulocyte count rose to 160% +/- 16%. 59Fe incorporation into the liver declined far below the level attributable to decreased accessibility of the tracer (84% +/- 4%). A shortening of the life span of late erythroblasts and circulating erythrocytes was deduced from these findings and methodological problems related to some of the seemingly controversial findings are discussed.

  16. Histone Deacetylase Inhibitors Trichostatin A and MCP30 Relieve Benzene-Induced Hematotoxicity via Restoring Topoisomerase IIα

    PubMed Central

    Chen, Yi; Li, Jiaqi; Qian, Shanhu; Shi, Yifen; Sun, Lan; Han, Yixiang; Zhang, Shenghui; Yu, Kang

    2016-01-01

    Dysfunction of histone acetylation inhibits topoisomerase IIα (Topo IIα), which is implicated in benzene-induced hematotoxicity in patients with chronic benzene exposure. Whether histone deacetylase (HDAC) inhibitors can relieve benzene-induced hematotoxicity remains unclear. Here we showed that hydroquinone, a main metabolite of benzene, increased the HDAC activity, decreased the Topo IIα expression and induced apoptosis in human bone marrow mononuclear cells in vitro, and treatment with two HDAC inhibitors, namely trichostatin A (TSA) or a mixture of ribosome-inactivating proteins MCP30, almost completely reversed these effects. We further established a benzene poisoning murine model by inhaling benzene vapor in a container and found that benzene poisoning decreased the expression and activity of Topo IIα, and impaired acetylation of histone H4 and H3. The analysis of regulatory factors of Topo IIα promoter found that benzene poisoning decreased the mRNA levels of SP1 and C-MYB, and increased the mRNA level of SP3. Both TSA and MCP30 significantly enhanced the acetylation of histone H3 and H4 in Topo IIα promoter and increased the expression and activity of Topo IIα in benzene poisoning mice, which contributed to relieve the symptoms of hematotoxicity. Thus, treatment with HDAC inhibitors represents an attractive approach to reduce benzene-induced hematotoxicity. PMID:27058040

  17. Histone Deacetylase Inhibitors Trichostatin A and MCP30 Relieve Benzene-Induced Hematotoxicity via Restoring Topoisomerase IIα.

    PubMed

    Chen, Jingjing; Zheng, Zhouyi; Chen, Yi; Li, Jiaqi; Qian, Shanhu; Shi, Yifen; Sun, Lan; Han, Yixiang; Zhang, Shenghui; Yu, Kang

    2016-01-01

    Dysfunction of histone acetylation inhibits topoisomerase IIα (Topo IIα), which is implicated in benzene-induced hematotoxicity in patients with chronic benzene exposure. Whether histone deacetylase (HDAC) inhibitors can relieve benzene-induced hematotoxicity remains unclear. Here we showed that hydroquinone, a main metabolite of benzene, increased the HDAC activity, decreased the Topo IIα expression and induced apoptosis in human bone marrow mononuclear cells in vitro, and treatment with two HDAC inhibitors, namely trichostatin A (TSA) or a mixture of ribosome-inactivating proteins MCP30, almost completely reversed these effects. We further established a benzene poisoning murine model by inhaling benzene vapor in a container and found that benzene poisoning decreased the expression and activity of Topo IIα, and impaired acetylation of histone H4 and H3. The analysis of regulatory factors of Topo IIα promoter found that benzene poisoning decreased the mRNA levels of SP1 and C-MYB, and increased the mRNA level of SP3. Both TSA and MCP30 significantly enhanced the acetylation of histone H3 and H4 in Topo IIα promoter and increased the expression and activity of Topo IIα in benzene poisoning mice, which contributed to relieve the symptoms of hematotoxicity. Thus, treatment with HDAC inhibitors represents an attractive approach to reduce benzene-induced hematotoxicity.

  18. Airborne Flux Measurements of Volatile Organic Compounds and NOx over a European megacity

    NASA Astrophysics Data System (ADS)

    Shaw, Marvin; Lee, James; Davison, Brian; Misztal, Pawel; Karl, Thomas; Hewitt, Nick; Lewis, Alistair

    2014-05-01

    Ground level ozone (O3) and nitrogen dioxide (NO2) are priority pollutants whose concentrations are closely regulated by European Union Air Quality Directive 2008/50/EC. O3 is a secondary pollutant, produced from a complex chemical interplay between oxides of nitrogen (NOx = NO + NO2) and volatile organic compounds (VOCs). Whilst the basic atmospheric chemistry leading to O3 formation is generally well understood, there are substantial uncertainties associated with the magnitude of emissions of both VOCs and NOx. At present our knowledge of O3 precursor emissions in the UK is primarily derived from National Atmospheric Emission inventories (NAEI) that provide spatially disaggregated estimates at 1x1km resolution, and these are not routinely tested at city or regional scales. Uncertainties in emissions propagate through into uncertainties in predictions of air quality in the future, and hence the likely effectiveness of control policies on both background and peak O3 and NO2 concentrations in the UK. The Ozone Precursor Fluxes in the Urban Environment (OPFUE) project aims to quantify emission rates for NOx and selected VOCs in and around the megacity of London using airborne eddy covariance (AEC). The mathematical foundation for AEC has been extensively reviewed and AEC measurements of ozone, dimethyl sulphide, CO2 and VOCs have been previously reported. During the summer of 2013, approximately 30 hours of airborne flux measurements of toluene, benzene, NO and NO2 were obtained from the NERC Airborne Research and Survey Facility's (ARSF) Dornier-228 aircraft. Over SE England, flights involved repeated south west to north east transects of ~50 km each over Greater London and it's surrounding suburbs and rural areas, flying at the aircraft's minimum operating flight altitude and airspeed (~300m, 80m/s). Mixing ratios of benzene and toluene were acquired at 2Hz using a proton transfer reaction mass spectrometer (PTR-MS) and compared to twice hourly whole air canister

  19. Density functional theory study of the interaction of vinyl radical, ethyne, and ethene with benzene, aimed to define an affordable computational level to investigate stability trends in large van der Waals complexes.

    PubMed

    Maranzana, Andrea; Giordana, Anna; Indarto, Antonius; Tonachini, Glauco; Barone, Vincenzo; Causà, Mauro; Pavone, Michele

    2013-12-28

    Our purpose is to identify a computational level sufficiently dependable and affordable to assess trends in the interaction of a variety of radical or closed shell unsaturated hydro-carbons A adsorbed on soot platelet models B. These systems, of environmental interest, would unavoidably have rather large sizes, thus prompting to explore in this paper the performances of relatively low-level computational methods and compare them with higher-level reference results. To this end, the interaction of three complexes between non-polar species, vinyl radical, ethyne, or ethene (A) with benzene (B) is studied, since these species, involved themselves in growth processes of polycyclic aromatic hydrocarbons (PAHs) and soot particles, are small enough to allow high-level reference calculations of the interaction energy ΔEAB. Counterpoise-corrected interaction energies ΔEAB are used at all stages. (1) Density Functional Theory (DFT) unconstrained optimizations of the A-B complexes are carried out, using the B3LYP-D, ωB97X-D, and M06-2X functionals, with six basis sets: 6-31G(d), 6-311 (2d,p), and 6-311++G(3df,3pd); aug-cc-pVDZ and aug-cc-pVTZ; N07T. (2) Then, unconstrained optimizations by Møller-Plesset second order Perturbation Theory (MP2), with each basis set, allow subsequent single point Coupled Cluster Singles Doubles and perturbative estimate of the Triples energy computations with the same basis sets [CCSD(T)//MP2]. (3) Based on an additivity assumption of (i) the estimated MP2 energy at the complete basis set limit [EMP2/CBS] and (ii) the higher-order correlation energy effects in passing from MP2 to CCSD(T) at the aug-cc-pVTZ basis set, ΔECC-MP, a CCSD(T)/CBS estimate is obtained and taken as a computational energy reference. At DFT, variations in ΔEAB with basis set are not large for the title molecules, and the three functionals perform rather satisfactorily even with rather small basis sets [6-31G(d) and N07T], exhibiting deviation from the computational

  20. Density functional theory study of the interaction of vinyl radical, ethyne, and ethene with benzene, aimed to define an affordable computational level to investigate stability trends in large van der Waals complexes.

    PubMed

    Maranzana, Andrea; Giordana, Anna; Indarto, Antonius; Tonachini, Glauco; Barone, Vincenzo; Causà, Mauro; Pavone, Michele

    2013-12-28

    Our purpose is to identify a computational level sufficiently dependable and affordable to assess trends in the interaction of a variety of radical or closed shell unsaturated hydro-carbons A adsorbed on soot platelet models B. These systems, of environmental interest, would unavoidably have rather large sizes, thus prompting to explore in this paper the performances of relatively low-level computational methods and compare them with higher-level reference results. To this end, the interaction of three complexes between non-polar species, vinyl radical, ethyne, or ethene (A) with benzene (B) is studied, since these species, involved themselves in growth processes of polycyclic aromatic hydrocarbons (PAHs) and soot particles, are small enough to allow high-level reference calculations of the interaction energy ΔEAB. Counterpoise-corrected interaction energies ΔEAB are used at all stages. (1) Density Functional Theory (DFT) unconstrained optimizations of the A-B complexes are carried out, using the B3LYP-D, ωB97X-D, and M06-2X functionals, with six basis sets: 6-31G(d), 6-311 (2d,p), and 6-311++G(3df,3pd); aug-cc-pVDZ and aug-cc-pVTZ; N07T. (2) Then, unconstrained optimizations by Møller-Plesset second order Perturbation Theory (MP2), with each basis set, allow subsequent single point Coupled Cluster Singles Doubles and perturbative estimate of the Triples energy computations with the same basis sets [CCSD(T)//MP2]. (3) Based on an additivity assumption of (i) the estimated MP2 energy at the complete basis set limit [EMP2/CBS] and (ii) the higher-order correlation energy effects in passing from MP2 to CCSD(T) at the aug-cc-pVTZ basis set, ΔECC-MP, a CCSD(T)/CBS estimate is obtained and taken as a computational energy reference. At DFT, variations in ΔEAB with basis set are not large for the title molecules, and the three functionals perform rather satisfactorily even with rather small basis sets [6-31G(d) and N07T], exhibiting deviation from the computational

  1. Density functional theory study of the interaction of vinyl radical, ethyne, and ethene with benzene, aimed to define an affordable computational level to investigate stability trends in large van der Waals complexes

    SciTech Connect

    Maranzana, Andrea E-mail: anna.giordana@hotmail.com E-mail: mauro.causa@unina.it Giordana, Anna E-mail: anna.giordana@hotmail.com E-mail: mauro.causa@unina.it Indarto, Antonius Tonachini, Glauco; Barone, Vincenzo E-mail: anna.giordana@hotmail.com E-mail: mauro.causa@unina.it; Causà, Mauro E-mail: anna.giordana@hotmail.com E-mail: mauro.causa@unina.it; Pavone, Michele E-mail: anna.giordana@hotmail.com E-mail: mauro.causa@unina.it

    2013-12-28

    Our purpose is to identify a computational level sufficiently dependable and affordable to assess trends in the interaction of a variety of radical or closed shell unsaturated hydro-carbons A adsorbed on soot platelet models B. These systems, of environmental interest, would unavoidably have rather large sizes, thus prompting to explore in this paper the performances of relatively low-level computational methods and compare them with higher-level reference results. To this end, the interaction of three complexes between non-polar species, vinyl radical, ethyne, or ethene (A) with benzene (B) is studied, since these species, involved themselves in growth processes of polycyclic aromatic hydrocarbons (PAHs) and soot particles, are small enough to allow high-level reference calculations of the interaction energy ΔE{sub AB}. Counterpoise-corrected interaction energies ΔE{sub AB} are used at all stages. (1) Density Functional Theory (DFT) unconstrained optimizations of the A−B complexes are carried out, using the B3LYP-D, ωB97X-D, and M06-2X functionals, with six basis sets: 6-31G(d), 6-311 (2d,p), and 6-311++G(3df,3pd); aug-cc-pVDZ and aug-cc-pVTZ; N07T. (2) Then, unconstrained optimizations by Møller-Plesset second order Perturbation Theory (MP2), with each basis set, allow subsequent single point Coupled Cluster Singles Doubles and perturbative estimate of the Triples energy computations with the same basis sets [CCSD(T)//MP2]. (3) Based on an additivity assumption of (i) the estimated MP2 energy at the complete basis set limit [E{sub MP2/CBS}] and (ii) the higher-order correlation energy effects in passing from MP2 to CCSD(T) at the aug-cc-pVTZ basis set, ΔE{sub CC-MP}, a CCSD(T)/CBS estimate is obtained and taken as a computational energy reference. At DFT, variations in ΔE{sub AB} with basis set are not large for the title molecules, and the three functionals perform rather satisfactorily even with rather small basis sets [6-31G(d) and N07T], exhibiting

  2. Antioxidant Compounds in Traditional Indian Pickles May Prevent the Process-Induced Formation of Benzene.

    PubMed

    Kharat, Mahesh M; Adiani, Vanshika; Variyar, Prasad; Sharma, Arun; Singhal, Rekha S

    2016-01-01

    Pickles in the Indian market contain ascorbic acid from the raw material used and benzoate as an added preservative that are involved in the formation of benzene in soft drinks. In this work, 24 market pickle samples were surveyed for benzene content, as well as its precursors and other constituents that influence its formation. The analysis showed that pickle samples were high in acid content (low pH) and showed significant amount of ascorbic acid, minerals (Cu and Fe), and benzoic acid present in them. Also, most samples exhibited high antioxidant activity that might be attributed to the ingredients used, such as fruits and spices. The solid-phase microextraction headspace gas chromatography-mass spectrometry method was developed in-house for benzene analysis. Eleven of 24 samples had benzene, with the highest concentration of 4.36 ± 0.82 μg of benzene per kg of pickle for a lime pickle that was also reported to have highest benzoic acid and considerably less hydroxyl radical ((•)OH) scavenging activity. However, benzene levels for all 11 samples were considerably below the World Health Organization regulatory limit of 10 μg/kg for benzene in mineral water. Studies on model systems revealed that the high antioxidant activity of Indian pickles may have had a strong inhibitory effect on benzene formation.

  3. Antioxidant Compounds in Traditional Indian Pickles May Prevent the Process-Induced Formation of Benzene.

    PubMed

    Kharat, Mahesh M; Adiani, Vanshika; Variyar, Prasad; Sharma, Arun; Singhal, Rekha S

    2016-01-01

    Pickles in the Indian market contain ascorbic acid from the raw material used and benzoate as an added preservative that are involved in the formation of benzene in soft drinks. In this work, 24 market pickle samples were surveyed for benzene content, as well as its precursors and other constituents that influence its formation. The analysis showed that pickle samples were high in acid content (low pH) and showed significant amount of ascorbic acid, minerals (Cu and Fe), and benzoic acid present in them. Also, most samples exhibited high antioxidant activity that might be attributed to the ingredients used, such as fruits and spices. The solid-phase microextraction headspace gas chromatography-mass spectrometry method was developed in-house for benzene analysis. Eleven of 24 samples had benzene, with the highest concentration of 4.36 ± 0.82 μg of benzene per kg of pickle for a lime pickle that was also reported to have highest benzoic acid and considerably less hydroxyl radical ((•)OH) scavenging activity. However, benzene levels for all 11 samples were considerably below the World Health Organization regulatory limit of 10 μg/kg for benzene in mineral water. Studies on model systems revealed that the high antioxidant activity of Indian pickles may have had a strong inhibitory effect on benzene formation. PMID:26735038

  4. High benzene concentrations can favour Gram-positive bacteria in groundwaters from a contaminated aquifer.

    PubMed

    Fahy, Anne; Ball, Andrew S; Lethbridge, Gordon; McGenity, Terry J; Timmis, Kenneth N

    2008-09-01

    Exposure to pollution exerts strong selective pressure on microbial communities, which may affect their potential to adapt to current or future environmental challenges. In this microcosm study, we used DNA fingerprinting based on 16S rRNA genes to document the impact of high concentrations of benzene on two bacterial communities from a benzene-contaminated aquifer situated below a petrochemical plant (SIReN, UK). The two groundwaters harboured distinct aerobic benzene-degrading communities able to metabolize benzene to below detection levels (1 microg L(-1)). A benzene concentration of 100 mg L(-1) caused a major shift from Betaproteobacteria to Actinobacteria, in particular Arthrobacter spp. A similar shift from Betaproteobacteria to Arthrobacter spp. and Rhodococcus erythropolis was observed in minimal medium (MM) inoculated with a third groundwater. These Gram-positive-dominated communities were able to grow on benzene at concentrations up to 600 mg L(-1) in groundwater and up to 1000 mg L(-1) in MM, concentrations that cause significant solvent stress to cellular systems. Therefore, Gram-positive bacteria were better competitors than Gram-negative organisms under experimental conditions of high benzene loads, which suggests that solvent-tolerant Gram-positive bacteria can play a role in the natural attenuation of benzene or the remediation of contaminated sites.

  5. S-phenylcysteine in albumin as a benzene biomarker

    SciTech Connect

    Bechtold, W.E.; Strunk, M.R.

    1996-12-01

    Biological markers of internal dose are useful for improving the extrapolation of health effects from exposures to high levels of toxic air pollutants in animals to low, ambient exposures in humans. Previous results from our laboratory have shown that benzene is metabolized by humans to form the adduct S-phenylcysteine (SPC). Levels of SPC measured in humans occupationally exposed to benzene were increased linearly relative to exposure concentrations ranging from 0 to 23.1 ppm for 8 hr/day, 5 days/week. However, the method of measurement used was laborious, prone to imprecision and interferences, and insufficiently sensitive for the low-dose exposures anticipated in the United States (100 ppb>). An improved chemical method was necessary before SPC adducts in albumin could be used as a benzene biomarker. A simple, sensitive method to measure SPC adducts is being developed and is based on the cleavage of the cysteine sulfhydryl from blood proteins treated with Raney nickel (RN) in deuterium oxide. The product of the reaction with SPC is monodeuterobenzene. SPC treated with RN released monodeuterobenzene in a concentration-dependent fashion. SPC was measured by RN treatment of globin from rats repeatedly exposed by inhalation to 600 ppm benzene. SPC levels measured using the RN approach were 690 {+-} 390 pmol SPC/mg Hb (mean {+-} % difference, n = 2), as opposed to 290 {+-} 45 pmol SPC/mg Hb (mean {+-} SEM, n = 3) as measured by our previous method. This method may facilitate the cost-effective, routine analysis of SPC in large populations of people exposed to ambient levels of benzene. 4 refs., 3 figs.

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

    PubMed

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

    2014-07-04

    Long-term exposure to benzene causes several adverse health effects, including an increased risk of acute myeloid leukemia. This study was to identify genetic alternations involved in pathogenesis of leukemia in benzene-exposed workers without clinical symptoms of leukemia. This study included 33 shoe-factory workers exposed to benzene at levels from 1 ppm to 10 ppm. These workers were divided into 3 groups based on the benzene exposure time, 1- < 7, 7- < 12, and 12- < 24 years. 17 individuals without benzene exposure history were recruited as controls. Cytogenetic analysis using Affymetrix Cytogenetics Array found copy-number variations (CNVs) in several chromosomes of benzene-exposed workers. Expression of targeted genes in these altered chromosomes, NOTCH1 and BSG, which play roles in leukemia pathogenesis, was further examined using real-time PCR. The NOTCH1 mRNA level was significantly increased in all 3 groups of workers, and the NOTCH1 mRNA level in the 12- < 24 years group was significantly higher than that in 1- < 7 and 7- < 12 years groups. Compared to the controls, the BSG mRNA level was significantly increased in 7- < 12 and 12- < 24 years groups, but not in the 1- < 7 years group. These results suggest that CNVs and leukemia-related gene expression might play roles in leukemia development in benzene-exposed workers.

  7. Reconstruction of benzene exposure for the Pliofilm cohort (1936-1976) using Monte Carlo techniques.

    PubMed

    Williams, Pamela R D; Paustenbach, Dennis J

    2003-04-25

    The current cancer slope factor and occupational standards for benzene are based primarily on studies of the rubber hydrochloride (Pliofilm) workers. Previous assessments of this cohort by Rinsky et al. (1981, 1987), Crump and Allen (1984), and Paustenbach et al. (1992) relied on different assumptions about the available industrial hygiene data and workplace practices and processes over time, thereby yielding significantly different estimates of annual benzene exposures for many jobs. Given the inherent limitations and uncertainties involved in estimating historical exposures for this cohort, a probabilistic approach was used to better characterize their likely degree of benzene exposure. Ambient air exposures to benzene were based, in part, on the distribution of air sampling data collected at the Pliofilm facilities and assumptions about how workplace concentrations probably decreased over time as the threshold limit value (TLV) was lowered. The likely uptake of benzene from dermal exposures was estimated based on probability distributions for several exposure factors, including surface area, contact rate and duration, and skin absorption. The assessment also quantitatively accounts for improved engineering controls, extended work hours, incomplete Pliofilm production, and the use and effectiveness of respirators over time. All original data and assumptions are presented in this assessment, as is all new information obtained through additional interviews of former workers. Estimated benzene exposures at the 50th and 95th percentiles are reported as equivalent 8-h time-weighted average (TWA) airborne concentrations for 13 job categories from 1936 to 1965 (Akron I and II facilities) and 1939 to 1976 (St. Mary's facility). Data indicate that estimated equivalent airborne benzene concentrations for St. Mary's workers were highest for four job categories (Neutralizer, Quencher, Knifeman, Spreader), typically ranging from about 50 to 90 ppm during 1939-1946 (lower

  8. Reconstruction of benzene exposure for the Pliofilm cohort (1936-1976) using Monte Carlo techniques.

    PubMed

    Williams, Pamela R D; Paustenbach, Dennis J

    2003-04-25

    The current cancer slope factor and occupational standards for benzene are based primarily on studies of the rubber hydrochloride (Pliofilm) workers. Previous assessments of this cohort by Rinsky et al. (1981, 1987), Crump and Allen (1984), and Paustenbach et al. (1992) relied on different assumptions about the available industrial hygiene data and workplace practices and processes over time, thereby yielding significantly different estimates of annual benzene exposures for many jobs. Given the inherent limitations and uncertainties involved in estimating historical exposures for this cohort, a probabilistic approach was used to better characterize their likely degree of benzene exposure. Ambient air exposures to benzene were based, in part, on the distribution of air sampling data collected at the Pliofilm facilities and assumptions about how workplace concentrations probably decreased over time as the threshold limit value (TLV) was lowered. The likely uptake of benzene from dermal exposures was estimated based on probability distributions for several exposure factors, including surface area, contact rate and duration, and skin absorption. The assessment also quantitatively accounts for improved engineering controls, extended work hours, incomplete Pliofilm production, and the use and effectiveness of respirators over time. All original data and assumptions are presented in this assessment, as is all new information obtained through additional interviews of former workers. Estimated benzene exposures at the 50th and 95th percentiles are reported as equivalent 8-h time-weighted average (TWA) airborne concentrations for 13 job categories from 1936 to 1965 (Akron I and II facilities) and 1939 to 1976 (St. Mary's facility). Data indicate that estimated equivalent airborne benzene concentrations for St. Mary's workers were highest for four job categories (Neutralizer, Quencher, Knifeman, Spreader), typically ranging from about 50 to 90 ppm during 1939-1946 (lower

  9. Superfund fact sheet: Benzene. Fact sheet

    SciTech Connect

    Not Available

    1992-09-01

    The fact sheet describes benzene, a chemical that can be found in a variety of products, including petroleum products (e.g. gasoline), some household cleaners, and some glues and adhesives. Explanations of how people are exposed to benzene and how benzene can enter the body and may affect human health are given. The fact sheet is one in a series providing reference information about Superfund issues and is intended for readers with no formal scientific training.

  10. Production of Phenol from Benzene via Cumene

    ERIC Educational Resources Information Center

    Daniels, D. J.; And Others

    1976-01-01

    Describes an undergraduate chemistry laboratory experiment involving the production of phenol from benzene with the intermediate production of isopropylbenzene and isopropylbenzene hydroperoxide. (SL)

  11. Acute cytogenetic effect of benzene on rat bone marrow cells in vivo and the effect of inducers or inhibitors of drug-metabolizing enzymes.

    PubMed

    Fujie, K; Ito, Y; Maeda, S

    1992-12-01

    Acute cytogenetic effects of benzene in LE rat bone marrow cells in vivo were studied. Chromosome aberrations (CA) induced by benzene consisted mainly of gaps and breaks. Cells with exchanges were rarely observed. The incidence of benzene-induced CA was at its maximum level 12 h after the p.o. or i.p. administration of benzene, dependent on the dose of benzene administered, and higher in male rats than in female rats. However, the sex difference was not observed in the repeated inhalation experiment. Chromosome damage was higher with the p.o. than the i.p. administration. LE rats were more sensitive than Wistar and SD rats to the clastogenic action of benzene. Phenobarbital and Sudan III are well known as inducers of drug-metabolizing enzymes. The peak percentage of benzene-induced CA in the rats pretreated with phenobarbital was observed 6 h after the benzene injection, and it occurred at a higher level than in the rats given only benzene. On the other hand, Sudan III pretreatment suppressed benzene-induced CA at all periods after the benzene injection. SKF-525A (a cytochrome P-450 inhibitor) and cyclohexene oxide (an epoxide hydrase inhibitor) pretreatment also suppressed benzene-induced CA.

  12. Detailed mechanism of benzene oxidation

    NASA Technical Reports Server (NTRS)

    Bittker, David A.

    1987-01-01

    A detailed quantitative mechanism for the oxidation of benzene in both argon and nitrogen diluted systems is presented. Computed ignition delay time for argon diluted mixtures are in satisfactory agreement with experimental results for a wide range of initial conditions. An experimental temperature versus time profile for a nitrogen diluted oxidation was accurately matched and several concentration profiles were matched qualitatively. Application of sensitivity analysis has given approximate rate constant expressions for the two dominant heat release reactions, the oxidation of C6H5 and C5H5 radicals by molecular oxygen.

  13. The harmonic frequencies of benzene

    NASA Astrophysics Data System (ADS)

    Handy, Nicholas C.; Maslen, Paul E.; Amos, Roger D.; Andrews, Jamie S.; Murray, Christopher W.; Laming, Gregory J.

    1992-09-01

    We report calculations for the harmonic frequencies of C 6H 6 and C 6D 6. Our most sophisticated quantum chemistry values are obtained with the MP2 method and a TZ2P+f basis set (288 basis functions), which are the largest such calculations reported on benzene to date. Using the SCF density, we also calculate the frequencies using the exchange and correlation expressions of density functional theory. We compare our calculated harmonic frequencies with those deduced from experiment by Goodman, Ozkabak and Thakur. The density functional frequencies appear to be more reliable predictions than the MP2 frequencies and they are obtained at significantly less cost.

  14. MEASUREMENT OF BENZENE OXIDE IN THE BLOOD OF RATS FOLLOWING ADMINISTRATION OF BENZENE

    EPA Science Inventory

    Although it is generally assumed that metabolism of benzene proceeds through an initial step involving oxidation to benzene oxide (BO) by CYP450 in the liver, the production of BO has never been unambiguously confirmed in animals dosed with benzene. Furthermore, prevailing hypo...

  15. Gas phase acidity of substituted benzenes

    NASA Astrophysics Data System (ADS)

    Bouchoux, Guy

    2011-04-01

    Deprotonation thermochemistry of benzene derivatives C 6H 5X (X = H, F, Cl, OH, NH 2, CN, CHO, NO 2, CH 3, C 2H 5, CHCH 2, CCH) has been examined at the G3B3 level of theory. For X = F, Cl, CN, CHO and NO 2, the most favorable deprotonation site is the ortho position of the phenyl ring. This regio-specificity is directly related to the field/inductive effect of the substituent. G3B3 gas phase acidities, Δ acidH° and Δ acidG°, compare within less than 4 kJ mol -1 with experimental data. A noticeable exception is nitrobenzene for which tabulated acidity appear to be underestimated by ca. 120 kJ mol -1.

  16. Chemical of current interest--benzene.

    PubMed

    Marcus, W L

    1987-03-01

    Benzene is one of the world's major commodity chemicals. It is derived from petroleum and coal and is used both as a solvent and as a starting material in chemical syntheses. The numerous industrial uses of benzene over the last century need not be recounted here, but the most recent addition to the list of uses of benzene is as a component in a mixture of aromatic compounds added to gasoline for the purpose of replacing lead compounds as anti-knock ingredients. The best known and longest recognized toxic effect of benzene is the depression of bone marrow function seen in occupationally exposed individuals. These people have been found to display anemia, leucopenia, and/or thrombocytopenia. When pancytopenia, i.e., the simultaneous depression of all three cell types, occurs and is accompanied by bone marrow necrosis, the syndrome is called aplastic anemia. In addition to observing this decrease in humans and relating it to benzene exposure, it has been possible to establish animal models which mimic the human disease. The result has been considerable scientific investigation into the mechanism of benzene toxicity. Although the association between benzene exposure and aplastic anemia has been recognized and accepted throughout most of this century, it is only recently that leukemia, particularly of the acute myelogenous type, has been related to benzene. The acceptance of benzene as an etiological agent in aplastic anemia in large measure derives from our ability to reproduce the disease in most animals treated with sufficiently high doses of benzene over the necessary time period. Unfortunately, despite extensive efforts in several laboratories, it has not been possible to establish a reproducible, reliable model for the study of benzene-induced leukemia. The recent demonstration that several animals exposed to benzene either by inhalation or in the drinking water during studies by Drs. B. Goldstein and C. Maltoni suggests that such a model may be forthcoming

  17. Mechanistic considerations in benzene physiological model development

    SciTech Connect

    Medinsky, M.A.; Kenyon, E.M.; Seaton, M.J.; Schlosser, P.M.

    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.

  18. Major sources of benzene exposure.

    PubMed Central

    Wallace, L A

    1989-01-01

    Data from EPA's TEAM Study allow us to identify the major sources of exposure to benzene for much of the U.S. population. These sources turn out to be quite different from what had previously been considered the important sources. The most important source of exposure for 50 million smokers is the mainstream smoke from their cigarettes, which accounts for about half of the total population burden of exposure to benzene. Another 20% of nationwide exposure is contributed by various personal activities, such as driving and using attached garages. (Emissions from consumer products, building materials, paints, and adhesives may also be important, although data are largely lacking.) The traditional sources of atmospheric emissions (auto exhaust and industrial emissions) account for only about 20% of total exposure. Environmental tobacco smoke is an important source, accounting for about 5% of total nationwide exposure. A number of sources sometimes considered important, such as petroleum refining operations, petrochemical manufacturing, oil storage tanks, urban-industrial areas, service stations, certain foods, groundwater contamination, and underground gasoline leaks, appear to be unimportant on a nationwide basis. PMID:2477239

  19. Major sources of benzene exposure

    SciTech Connect

    Wallace, L.A. )

    1989-07-01

    Data from EPA's TEAM Study allow us to identify the major sources of exposure to benzene for much of the U.S. population. These sources turn out to be quite different from what had previously been considered the important sources. The most important source of exposure for 50 million smokers is the mainstream smoke from their cigarettes, which accounts for about half of the total population burden of exposure to benzene. Another 20% of nationwide exposure is contributed by various personal activities, such as driving and using attached garages. (Emissions from consumer products, building materials, paints, and adhesives may also be important, although data are largely lacking.) The traditional sources of atmospheric emissions (auto exhaust and industrial emissions) account for only about 20% of total exposure. Environmental tobacco smoke is an important source, accounting for about 5% of total nationwide exposure. A number of sources sometimes considered important, such as petroleum refining operations, petrochemical manufacturing, oil storage tanks, urban-industrial areas, service stations, certain foods, groundwater contamination, and underground gasoline leaks, appear to be unimportant on a nationwide basis.

  20. Resonant photodissociation in substituted benzenes

    NASA Astrophysics Data System (ADS)

    Scarborough, Tim; McAcy, Collin; Foote, David; Uiterwaal, Cornelis

    2011-05-01

    Cyclic aromatic molecules are abundant in organic chemistry, with a wide variety of applications, including pharmacology, pollution studies and genetic research. Among the simplest of these molecules is benzene (C6H6) , with many relevant molecules being benzene-like with a single atomic substitution. In such a substitution, the substituent determines a characteristic perturbation of the electronic structure of the molecule. We discuss the substitution of halogens into the ring (C6H5X), and its effects on the dynamics of ionization and dissociation of the molecule without the focal volume effect. In particular, using 800-nm, 50-fs laser pulses, we present results in the dissociation of fluorobenzene, chlorobenzene, bromobenzene and iodobenzene into the phenyl ring (C6H5) and the atomic halogen, and the subsequent ionization of these fragments. The impact of the ``heavy atom effect'' on a 1 (π , π*) -->3 (n , σ*) singlet-triplet intersystem crossing will be emphasized. Currently under investigation is whether such a dissociation can be treated as an effective source of the neutral substituent. This material is based upon work supported by the National Science Foundation under Grant No. PHY-0355235.

  1. Major sources of benzene exposure.

    PubMed

    Wallace, L A

    1989-07-01

    Data from EPA's TEAM Study allow us to identify the major sources of exposure to benzene for much of the U.S. population. These sources turn out to be quite different from what had previously been considered the important sources. The most important source of exposure for 50 million smokers is the mainstream smoke from their cigarettes, which accounts for about half of the total population burden of exposure to benzene. Another 20% of nationwide exposure is contributed by various personal activities, such as driving and using attached garages. (Emissions from consumer products, building materials, paints, and adhesives may also be important, although data are largely lacking.) The traditional sources of atmospheric emissions (auto exhaust and industrial emissions) account for only about 20% of total exposure. Environmental tobacco smoke is an important source, accounting for about 5% of total nationwide exposure. A number of sources sometimes considered important, such as petroleum refining operations, petrochemical manufacturing, oil storage tanks, urban-industrial areas, service stations, certain foods, groundwater contamination, and underground gasoline leaks, appear to be unimportant on a nationwide basis.

  2. Biological monitoring of benzene exposure for process operators during ordinary activity in the upstream petroleum industry.

    PubMed

    Bråtveit, Magne; Kirkeleit, Jorunn; Hollund, Bjørg Eli; Moen, Bente E

    2007-07-01

    This study characterized the exposure of crude oil process operators to benzene and related aromatics during ordinary activity and investigated whether the operators take up benzene at this level of exposure. We performed the study on a fixed, integrated oil and gas production facility on Norway's continental shelf. The study population included 12 operators and 9 referents. We measured personal exposure to benzene, toluene, ethylbenzene and xylene during three consecutive 12-h work shifts using organic vapour passive dosimeter badges. We sampled blood and urine before departure to the production facility (pre-shift), immediately after the work shift on Day 13 of the work period (post-shift) and immediately before the following work shift (pre-next shift). We also measured the exposure to hydrocarbons during short-term tasks by active sampling using Tenax tubes. The arithmetic mean exposure over the 3 days was 0.042 ppm for benzene (range <0.001-0.69 ppm), 0.05 ppm for toluene, 0.02 ppm for ethylbenzene and 0.03 ppm for xylene. Full-shift personal exposure was significantly higher when the process operators performed flotation work during the shift versus other tasks. Work in the flotation area was associated with short-term (6-15 min) arithmetic mean exposure to benzene of 1.06 ppm (range 0.09-2.33 ppm). The concentrations of benzene in blood and urine did not differ between operators and referents at any time point. When we adjusted for current smoking in regression analysis, benzene exposure was significantly associated with the post-shift concentration of benzene in blood (P = 0.01) and urine (P = 0.03), respectively. Although these operators perform tasks with relatively high short-term exposure to benzene, the full-shift mean exposure is low during ordinary activity. Some evidence indicates benzene uptake within this range of exposure.

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

    PubMed

    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

  4. Endotoxins in baled cottons and airborne dusts in textile mills in the People's Republic of China.

    PubMed Central

    Olenchock, S A; Christiani, D C; Mull, J C; Ye, T T; Lu, P L

    1983-01-01

    Bulk cotton samples and airborne vertical elutriated cotton dusts were obtained from textile mills in Shanghai, People's Republic of China. Analysis of endotoxin contents revealed that baled cottons which were grown in different countries varied in endotoxin contamination. The two textile mills, which operated at similar overall airborne dust levels, differed markedly in the levels of airborne endotoxins. The data suggest that the biological activity or "toxicity" of airborne cotton dusts may not be correlated directly with gravimetric dust levels. PMID:6639029

  5. [Analysis of the methods of evaluation of occupational exposure to benzene and phenol of petrochemical industry workers].

    PubMed

    Andrzejewski, S; Paradowski, M; Lis, E; Rojewiska, E

    1981-01-01

    209 workers exposed to airborne benzene and phenol at the Mazovian Refining Petrochemical Works, at three different plants, i.e. of Phenol, Gasoline Composing and Water -- Wastes, have been examined. It has been demonstrated that urine phenol content in workers working in an open plant area is very often inadequate to the airborne time-weighted averaged concentration of benzene and phenol. It has been shown more advisable to determine urine phenol concentrations twice: before and after the work shift. At the same time some specific methods have been recommended for determining phenol concentrations in urine. These are: gas chromatographic method of Dirmikis and Darbre, modified in this laboratory, and Gibbs' colorimetric method modified by Bardodej with 4-amino-antipyrine or Gibbs' colorimetric method with 2,6-dibromoquinone-4-chloroimide modified by Hanke et al. The Theis-Benedict method should not be applied in medical analytical laboratory because of its low specificity to phenol.

  6. Hematological effect of benzene exposure with emphasis of muconic acid as a biomarker.

    PubMed

    Ibrahim, Khadiga S; Amer, Nagat M; El-dossuky, Elsaid A; Emara, Ahmed M; El-Fattah, Abd El-Samei M Abd; Shahy, Eman Mohamed

    2014-06-01

    Human exposure to benzene in work environment is a global occupational health problem. It is established that benzene requires to be metabolized to induce its effects. Benzene has been associated with various hematotoxins and carcinogens. The aim of this study was to investigate the effect of benzene on complete blood picture, with emphasis of trans, trans-muconic acid (t,t-MA) as a biomarker of benzene in urine, considering the influence of cigarette smoke. A total of 81 workers (61 males and 20 females) have been occupationally exposed to benzene. In addition, 83 workers (55males and 28 females) were also recruited as a control group. Complete blood picture was analyzed and urinary t,t-MA was determined by liquid chromatography. In addition, creatinine in the urine samples was determined. Levels of blood elements (white blood cells, red blood cells and platelets) were decreased among exposed workers compared with the controls. The urinary level of t,t-MA/creatinine of the exposed workers was elevated especially in the smoking group compared to the controls. This study recommends that complete blood picture and t,t-MA are helpful biomarker tests that should be done to detect the early effects of benzene exposure.

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

    PubMed

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

    2013-02-01

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

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

    PubMed Central

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

    2013-01-01

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

  9. 46 CFR 151.50-60 - Benzene.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 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 1915.1028 - Benzene.

    Code of Federal Regulations, 2010 CFR

    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...

  11. 46 CFR 30.25-3 - Benzene.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 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...

  12. 29 CFR 1926.1128 - Benzene.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 8 2014-07-01 2014-07-01 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....

  13. 46 CFR 30.25-3 - Benzene.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 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...

  14. 46 CFR 151.50-60 - Benzene.

    Code of Federal Regulations, 2010 CFR

    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...

  15. 29 CFR 1926.1128 - Benzene.

    Code of Federal Regulations, 2010 CFR

    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....

  16. 29 CFR 1926.1128 - Benzene.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 8 2012-07-01 2012-07-01 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....

  17. 29 CFR 1915.1028 - Benzene.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 7 2013-07-01 2013-07-01 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...

  18. 29 CFR 1910.1028 - Benzene.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... safety data sheet (MSDS) which addresses benzene and complies with 29 CFR 1910.1200. (ii) Employers who... the requirements of 29 CFR 1910.1200(h) (1) and (2), and shall include specific information on benzene... and unloading operations, except for the provisions of 29 CFR 1910.1200 as incorporated into...

  19. 46 CFR 151.50-60 - Benzene.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 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...

  20. 46 CFR 151.50-60 - Benzene.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 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...

  1. 29 CFR 1915.1028 - Benzene.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 7 2014-07-01 2014-07-01 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...

  2. 46 CFR 30.25-3 - Benzene.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 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...

  3. 29 CFR 1926.1128 - Benzene.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 8 2013-07-01 2013-07-01 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....

  4. 29 CFR 1910.1028 - Benzene.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... safety data sheet (MSDS) which addresses benzene and complies with 29 CFR 1910.1200. (ii) Employers who... the requirements of 29 CFR 1910.1200(h) (1) and (2), and shall include specific information on benzene... and unloading operations, except for the provisions of 29 CFR 1910.1200 as incorporated into...

  5. 29 CFR 1915.1028 - Benzene.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 7 2011-07-01 2011-07-01 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...

  6. 29 CFR 1915.1028 - Benzene.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 7 2012-07-01 2012-07-01 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...

  7. 46 CFR 30.25-3 - Benzene.

    Code of Federal Regulations, 2010 CFR

    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...

  8. 46 CFR 151.50-60 - Benzene.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 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...

  9. 46 CFR 30.25-3 - Benzene.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 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...

  10. 29 CFR 1926.1128 - Benzene.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 8 2011-07-01 2011-07-01 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. Degradation of benzene in the environment

    SciTech Connect

    Korte, F.; Klein, W.

    1982-01-01

    A test system for measurement of benzene and other aromatic compounds using a carbon 14 label is described. The biodegradability test of ecotoxicological profile analysis is performed in a closed system, thus allowing the investigation of volatile compounds. Results show that benzene is readily biodegradable. (JMT)

  12. Association between intrafollicular concentration of benzene and outcome of controlled ovarian stimulation in IVF/ICSI cycles: a pilot study

    PubMed Central

    2014-01-01

    Background Several studies have shown that exposure to benzene is associated to menstrual disorders, miscarriages and other disorders of the reproductive system. We performed an observational prospective pilot study to evaluate if levels of benzene in follicular fluid were correlated with response to controlled ovarian stimulation. Method Thirty-four normogonadotrophic women undergoing IVF were enrolled. Intra-follicular benzene levels were evaluated by chromatography/mass spectrometry. Based on median benzene level, we divided the study population in two groups: Group A with a “low” intra-follicular benzene concentration (n = 19, benzene <0.54 ng/mL) and Group B with a “high” intra-follicular benzene concentration (n = 15, benzene ≥ 0.54 ng/mL). The ovarian response to gonadotrophins and the outcome of IVF were analyzed in the two groups. Results The two groups did not differ in terms of demographic or anthropometric characteristics. Group B had significantly higher basal FSH levels, lower estradiol peak concentration, and fewer oocytes retrieved and embryos transferred (p < 0.05). Number of gonadotrophin vials, length of controlled ovarian stimulation and ongoing pregnancy rate were similar in the two groups. Conclusion In conclusion, ovarian response to endogenous and exogenous gonadotrophins appeared to be influenced by intra-follicular benzene levels. PMID:24991235

  13. Biofiltration control of VOC and air toxic emissions: n-Butane and benzene

    SciTech Connect

    Allen, E.R.

    1996-12-31

    n-Butane and benzene vapors are routinely observed in urban atmospheres. Their presence in urban airsheds is of concern because of their ozone production potential as volatile organic compounds (VOCs) and/or potential toxicity. Also, these saturated hydrocarbons are representative of airborne aliphatic and aromatic compounds. Separate laboratory studies have been conducted on the biological elimination of n-butane (n-C{sub 4}H{sub 10}) and benzene (C{sub 6}H{sub 6}) from airstreams using treated compost biofilters. The removal efficiencies were found to exceed 90% for a conditioned biofilter medium and pollutant low concentrations (< 25 ppm) and zeroth order kinetics at higher concentrations (> 100 ppm), whereas benzene vapor elimination followed zeroth order kinetics at concentrations up to 200 ppm. The maximum n-butane and benzene elimination capacities observed for the compost biofilters and conditions employed were 25 and 70 g pollutant m{sup -3} h{sup -1}, respectively. 13 refs., 6 figs., 2 tabs.

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

    PubMed Central

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

    2000-01-01

    Although automobile refueling represents the major source of benzene exposure among the nonsmoking public, few data are available regarding such exposures and the associated uptake of benzene. We repeatedly measured benzene exposure and uptake (via benzene in exhaled breath) among 39 self-service customers using self-administered monitoring, a technique rarely used to obtain measurements from the general public (130 sets of measurements were obtained). Benzene exposures averaged 2.9 mg/m(3) (SD = 5.8 mg/m(3); median duration = 3 min) with a range of < 0.076-36 mg/m(3), and postexposure breath levels averaged 160 microg/m(3) (SD = 260 microg/m(3)) with a range of < 3.2-1,400 microg/m(3). Log-transformed exposures and breath levels were significantly correlated (r = 0.77, p < 0.0001). We used mixed-effects statistical models to gauge the relative influences of environmental and subject-specific factors on benzene exposure and breath levels and to investigate the importance of various covariates obtained by questionnaire. Model fitting yielded three significant predictors of benzene exposure, namely, fuel octane grade (p = 0.0011), duration of exposure (p = 0.0054), and season of the year (p = 0.032). Likewise, another model yielded three significant predictors of benzene concentration in breath, specifically, benzene exposure (p = 0.0001), preexposure breath concentration (p = 0.0008), and duration of exposure (p = 0.038). Variability in benzene concentrations was remarkable, with 95% of the estimated values falling within a 274-fold range, and was comprised entirely of the within-person component of variance (representing exposures of the same subject at different times of refueling). The corresponding range for benzene concentrations in breath was 41-fold and was comprised primarily of the within-person variance component (74% of the total variance). Our results indicate that environmental rather than interindividual differences are primarily responsible for

  15. Relationship Between Indoor Air Pollutant Levels and Residential Environment in Children With Atopic Dermatitis

    PubMed Central

    Lee, Jung Hyun; Lee, Ho Seok; Park, Mi Ran; Lee, Sang Woon; Kim, Eun Hye; Cho, Joong Bum; Kim, Jihyun; Han, Youngshin; Jung, Kweon; Cheong, Hae Kwan; Lee, Sang Il

    2014-01-01

    Purpose This study was aimed to investigate the relationship between indoor air pollutant levels and residential environment in children with atopic dermatitis (AD) living in Seoul. Methods A total of 150 children with AD were included. Residential environment was assessed by questionnaires which were completed by their parents. To evaluate the level of exposure to the indoor air pollutants, concentrations of the indoor air pollutants including particulate matter with diameter less than 10 µm (PM10), formaldehyde, carbon dioxide (CO2), carbon monoxide (CO), nitrogen dioxide (NO2), Total Volatile Organic Compound (TVOC), benzene, toluene, ethyl-benzene, xylene, styrene, bacterial aerosols, and airborne fungi were measured. Results A significant difference was exhibited in the levels of PM10 in case of visible fungus on the walls (P=0.047). There was relationship between the construction year of the house, moving to a newly constructed building within 1 year and formaldehyde level. With the use of artificial air freshener, the differences were found in the concentrations of TVOC (P=0.003), benzene (P=0.015), toluene (P=0.012) and ethyl-benzene (P=0.027). The concentration of xylene was significantly high when oil was used as heating fuel (P=0.015). Styrene exhibited differences depending on building type and its concentrations were significantly high in a residential and commercial complex building (P=0.005). The indoor concentration of bacterial aerosols was significantly low with the use of air cleaner (P=0.045). High NO2, benzene concentrations were present in case of almost no ventilation (P=0.028 and P=0.028, respectively). Conclusions Individual residential environments are closely related with the levels of the indoor air pollutants. To alleviate AD symptoms, simple questions about residential environments such as visible fungus on the walls and the use of artificial air freshener are helpful to assess the possibility of increased indoor air pollutant levels

  16. Mitochondrial DNA copy number and hnRNP A2/B1 protein: biomarkers for direct exposure of benzene.

    PubMed

    Eom, Ha-Young; Kim, Hye-Ran; Kim, Hwan-Young; Han, Dong-Kyun; Baek, Hee-Jo; Lee, Jae-Hyuk; Moon, Jai Dong; Shin, Jong-Hee; Suh, Soon-Pal; Ryang, Dong-Wook; Kook, Hoon; Shin, Myung-Geun

    2011-12-01

    The present study was performed to identify biomarkers for exposure of benzene in blood cells and hematopoietic tissues. Peripheral mononuclear cells, hematopoietic stem cells, and leukemia cell lines were cultured in RPMI 1640 media with the addition of 0, 1, and 10 mM of benzene. Hydrogen peroxide was measured using an enzyme immunoassay. Mitochondrial mass, membrane potential, and mitochondrial DNA (mtDNA) copy number were measured using MitoTracker Green/Red probes, and real-time polymerase chain reaction. In addition, two-dimensional gel electrophoresis and mass spectrometry matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) technology were performed to identify protein markers. The mitochondrial contents and membrane potentials were dramatically increased after three weeks of direct benzene exposure. The hydrogen peroxide level increased significantly after two weeks of treatment with benzene (4.4 ± 1.9 µM/mg protein) compared to the non-benzene treatment group (1.2 ± 1.0; p = 0.001). The mtDNA copy number gradually increased after exposure to benzene. Numerous protein markers showed significant aberrant expression after exposure to benzene. Among them, the heterogeneous nuclear ribonucleoprotein (hnRNP) A2/B1 was markedly decreased after exposure to benzene. Thus, increased mitochondrial mass, mtDNA copy number, and the hnRNP A2/B1 protein were biomarkers for benzene-related toxicity and hematotoxicity.

  17. Occupational exposure to benzene at the ExxonMobil refinery in Baytown, TX (1978-2006).

    PubMed

    Gaffney, Shannon H; Panko, Julie M; Unice, Ken M; Burns, Amanda M; Kreider, Marisa L; Gelatt, Richard H; Booher, Lindsay E; Paustenbach, Dennis J

    2011-01-01

    Although occupational benzene exposure of refinery workers has been studied for decades, no extensive analysis of historical industrial hygiene data has been performed focusing on airborne concentrations at specific refineries and tasks. This study characterizes benzene exposures at the ExxonMobil Baytown, TX, refinery from 1978 to 2006 to understand the variability in workers' exposures over time and during different job tasks. Exposures were grouped by operational status, job title, and tasks. More than 9000 industrial hygiene air samples were evaluated; approximately 4000 non-task (> 3 h) and 1000 task-related (< 3 h) personal samples were considered. Each sample was assigned to one of 27 job titles, 29 work areas, and 16 task bins (when applicable). Process technicians were sampled most frequently, resulting in the following mean benzene concentrations by area: hydrofiner (n=245, mean=1.3 p.p.m.), oil movements (n=286, mean=0.23 p.p.m.), reformer (n=575, mean=0.10 p.p.m.), tank farm (n=9, mean=0.65 p.p.m.), waste treatment (n=446, mean=0.13 p.p.m.), and other areas (n=460, mean=0.062 p.p.m.). The most frequently sampled task was sample collection (n=218, mean=0.40 p.p.m.). Job title and area did not significantly impact task-related exposures. Airborne concentrations were significantly lower after 1990 than before 1990. Results of this task-focused study may be useful when analyzing benzene exposures at other refineries.

  18. Percutaneous penetration of benzene and benzene contained in solvents used in the rubber industry

    SciTech Connect

    Maibach, H.I.; Anjo, D.M.

    1981-09-01

    Penetration of benzene through the skin of the rhesus monkey was determined using /sup 14/C-benzene, and quantitating the labelled metabolites in urine. The modes of application and amounts of benzene that penetrated the skin (indicated in parentheses) are as follows: (1) a single, direct cutaneous application of liquid benzene (0.172 +/- 0.139%); (2) a single application of benzene-containing (0.36%) solvent (0.0805 +/- 0.0306%); (3) multiple washes with full-strength benzene (0.848 +/- 0.0806%); (4) multiple washes with the benzene-containing (0.35%) solvent (0.431 +/- 0.258%); (5) removal of the stratum corneum followed by application of full-strength benzene (0.09 +/- 0.627%); and (6) application of benzene to the palmar surface (0.651 +/- 0.482%). Until more complete human data becomes available, benzene penetration in the monkey may be used to estimate penetration in man, both for industrial hygiene purposes and general toxicological use.

  19. Airborne particulate matter in spacecraft

    NASA Technical Reports Server (NTRS)

    1988-01-01

    Acceptability limits and sampling and monitoring strategies for airborne particles in spacecraft were considered. Based on instances of eye and respiratory tract irritation reported by Shuttle flight crews, the following acceptability limits for airborne particles were recommended: for flights of 1 week or less duration (1 mg/cu m for particles less than 10 microns in aerodynamic diameter (AD) plus 1 mg/cu m for particles 10 to 100 microns in AD); and for flights greater than 1 week and up to 6 months in duration (0.2 mg/cu m for particles less than 10 microns in AD plus 0.2 mg/cu m for particles 10 to 100 microns in AD. These numerical limits were recommended to aid in spacecraft atmosphere design which should aim at particulate levels that are a low as reasonably achievable. Sampling of spacecraft atmospheres for particles should include size-fractionated samples of 0 to 10, 10 to 100, and greater than 100 micron particles for mass concentration measurement and elementary chemical analysis by nondestructive analysis techniques. Morphological and chemical analyses of single particles should also be made to aid in identifying airborne particulate sources. Air cleaning systems based on inertial collection principles and fine particle collection devices based on electrostatic precipitation and filtration should be considered for incorporation into spacecraft air circulation systems. It was also recommended that research be carried out in space in the areas of health effects and particle characterization.

  20. Reduction of benzene toxicity by toluene.

    PubMed

    Plappert, U; Barthel, E; Seidel, H J

    1994-01-01

    BDF1 mice were exposed in inhalation chambers to benzene (900 ppm, 300 ppm) and/or toluene (500 ppm, 250 ppm) 6 hr per day, 5 days per week, for up to 8 weeks. Benzene alone induced a slight anemia after 4 and 8 weeks and a reduction of BFU-E and CFU-E numbers in the marrow. The coexposure to toluene reduced the degree of anemia. These results confirm previous studies where toluene was found to reduce benzene toxicity. This protective effect was most pronounced when DNA damage was studied in peripheral blood cells, bone marrow, and liver using the single cell gel (SCG) assay. With benzene alone, either with 300 or 900 ppm, a significant increase in DNA damage was detected in cells sampled from all three organs. Toluene alone did not induce a significant increase in DNA damage. The coexposure of benzene and toluene reduced the extent of DNA damage to about 50% of benzene alone. This result is considered a clear indication for a protective effect of toluene on the genetic toxicity of benzene.

  1. Reduction of benzene toxicity by toluene

    SciTech Connect

    Plappert, U.; Barthel, E.; Seidel, H.J.

    1994-12-31

    BDF{sub 1} mice were exposed in inhalation chambers to benzene (900 ppm, 300 ppm) and/or toluene (500 ppm, 250 ppm) 6 hr per day, 5 days per week, for up to 8 weeks. Benzene alone induced a slight anemia after 4 and 8 weeks and a reduction of BFU-E and CFU-E numbers in the marrow. The coexposure to toluene reduced the degree of anemia. These results confirm previous studies where toluene was found to reduce benzene toxicity. This protective effect was most pronounced when DNA damage was studied in peripheral blood cells, bone marrow, and liver using the single cell gel (SCG) assay. With benzene alone, either with 300 or 900 ppm, a significant increase in DNA damage was detected in cells sampled from all three organs. Toluene alone did not induce a significant increase in DNA damage. The coexposure of benzene and toluene reduced the extent of DNA damage to about 50% of benzene alone. This result is considered a clear indication for a protective effect of toluene on the genetic toxicity of benzene. 18 refs., 7 figs., 3 tabs.

  2. Raytheon low temperature RSP2 cryocooler airborne testing

    NASA Astrophysics Data System (ADS)

    Schaefer, B. R.; Bellis, L.; Ellis, M. J.; Conrad, T. J.

    2014-01-01

    The Raytheon Cryocooler Product Line tested the Low Temperature Stirling / Pulse Tube Hybrid 2-Stage (LTRSP2) cryocooler for an airborne application during 2012. Several tests were carried out to verify the ability of the machine to operate in an airborne environment. The vacuum level and heat rejection surface temperatures were varied to determine the performance over the excursions. Vibration testing was performed to prove that the LT-RSP2 cryocooler can operate on an airborne platform. This paper will present the results of the airborne characterization testing.

  3. Raytheon low temperature RSP2 cryocooler airborne testing

    NASA Astrophysics Data System (ADS)

    Schaefer, B. R.; Bellis, L.; Ellis, M. J.; Conrad, T. J.

    2013-09-01

    The Raytheon Cryocooler Product Line tested the Low Temperature Stirling / Pulse Tube Hybrid 2-Stage (LTRSP2) cryocooler for an airborne application during 2012. Several tests were carried out to verify the ability of the machine to operate in an airborne environment. The vacuum level and heat rejection surface temperatures were varied to determine the performance over the excursions. Vibration testing was performed to prove that the LT-RSP2 cryocooler can operate on an airborne platform. This paper will present the results of the airborne characterization testing.

  4. Mars Airborne Prospecting Spectrometer

    NASA Astrophysics Data System (ADS)

    Steinkraus, J. M.; Wright, M. W.; Rheingans, B. E.; Steinkraus, D. E.; George, W. P.; Aljabri, A.; Hall, J. L.; Scott, D. C.

    2012-06-01

    One novel approach towards addressing the need for innovative instrumentation and investigation approaches is the integration of a suite of four spectrometer systems to form the Mars Airborne Prospecting Spectrometers (MAPS) for prospecting on Mars.

  5. Benzene: a secondary pollutant formed in the three-way catalyst.

    PubMed

    Bruehlmann, Stefan; Forss, Anna-Maria; Steffen, Dominik; Heeb, Norbert V

    2005-01-01

    Benzene emissions from a relevant proportion of today's gasoline-driven passenger cars and light-duty vehicles can increase by up to 2 orders of magnitude when driving at high engine load (e.g., on highways). Under such conditions, post-catalyst benzene levels exceeded those found pre-catalyst. As a consequence, formation of benzene in the catalyst was postulated. To further reduce ambient air concentrations of benzene,these critical operating conditions must be carefully avoided. Here, we report in detail to what extent and at what operating conditions catalyst-induced benzene and toluene formation can occur. For that purpose, a EURO-1 passenger car (1.8 L, model year 1995)fulfilling the valid regulations, equipped with a new, two-layered, Pd-CeO2-Al2O3/Rh-ZrO2-Al2O3 three-way catalyst was operated at steady state on a chassis dynamometer at 100, 125, and 150 km/h at variable air to fuel ratios. Pre- and post-catalyst exhaust gas concentrations of benzene, toluene, C2-, and C3-benzenes were monitored at a time resolution of 0.5 Hz by means of chemical ionization mass spectrometry. A net benzene formation window, ranging from pre-catalyst exhaust gas temperatures of 600-730 degrees C and lambda-values of 0.83-0.95, with a pronounced minimum at 0.87, was observed. Dealkylation reactions of aromatic hydrocarbons are assumed to be the major pathway leading to benzene. PMID:15667114

  6. The nature of chromosomal aberrations detected in humans exposed to benzene.

    PubMed

    Zhang, Luoping; Eastmond, David A; Smith, Martyn T

    2002-01-01

    Benzene is an established cause of human leukemia that is thought to act by producing chromosomal aberrations and altered in cell differentiation. In several recent studies increased levels of chromosomal aberrations in peripheral blood lymphocytes were correlated with a heightened risk of cancer, especially hematological malignancies. Thus, chromosomal aberrations may be a predictor of future leukemia risk. Previous studies exploring whether benzene exposure induces chromosomal aberrations have yielded mostly positive results. However, it remains unclear whether the chromosomal aberrations induced by benzene occur in a distinct pattern. Here, we thoroughly review the major chromosome studies published to date in benzene-exposed workers, benzene-poisoned and preleukemia patients, and leukemia cases associated with benzene expose. Although three cytogenetic markers (chromosomal aberrations, sister chromatid exchanges, and micronuclei) are commonly examined, our primary focus is on studies of chromosomal aberrations, because only this marker has so far been correlated with increased cancer risk. This review surveys the published literature, analyzes the study results, and discusses the characteristics of effects reported. In most studies of currently exposed workers, increases in chromosomal aberrations were observed. However, due to the relatively small number of affected individuals and variability in the reported aberrations, firm conclusions cannot be made about the involvement of specific chromosomes or chromosome regions. Further, in leukemia cases associated with benzene exposure, there is no evidence of a unique pattern of benzene-induced chromosomal aberrations in humans. Leukemia cases associated with benzene exposure are, however, more likely to contain clonal chromosome aberrations then those arising de novo in the general population.

  7. Variations in Prkdc and susceptibility to benzene-induced toxicity in mice.

    PubMed

    Faiola, Brenda; Bauer, Alison K; Fuller, Elizabeth S; Wong, Victoria A; Pluta, Linda J; Abernethy, Diane J; Mangum, James B; Everitt, Jeffrey I; Recio, Leslie

    2003-10-01

    Benzene, a carcinogen that induces chromosomal breaks, is strongly associated with leukemias in humans. Possible genetic determinants of benzene susceptibility include proteins involved in repair of benzene-induced DNA damage. The catalytic subunit of DNA-dependent protein kinase (DNA-PKcs), encoded by Prkdc, is one such protein. DNA-PKcs is involved in the nonhomologous end-joining (NHEJ) pathway of DNA double-strand break (DSB) repair. Here we compared the toxic effects of benzene on mice (C57BL/6 and 129/Sv) homozygous for the wild-type Prkdc allele and mice (129/SvJ) homozygous for a Prkdc functional polymorphism that leads to diminished DNA-PK activity and enhanced apoptosis in response to radiation-induced damage. Male and female mice were exposed to 0, 10, 50, or 100 ppm benzene for 6 h/d, 5 d/week for 2 weeks. Male mice were more susceptible to benzene toxicity compared with females. Hematotoxicity was evident in all male mice but was not seen in female mice. We observed similar, large increases in both micronucleated erythrocyte populations in all male mice. Female mice had smaller but significant increases in micronucleated cells. The p53-dependent response was induced in all strains and genders of mice following benzene exposure, as indicated by an increase in p21 mRNA levels in bone marrow that frequently corresponded with cell cycle arrest in G2/M. Prkdc does not appear to be a significant genetic susceptibility factor for acute benzene toxicity. Moreover, the role of NHEJ, mediated by DNA-PK, in restoring genomic integrity following benzene-induced DSB remains equivocal.

  8. Lidar Measurements of Industrial Benzene Emissions

    NASA Astrophysics Data System (ADS)

    Berkhout, A. J. C.; van der Hoff, G. R.; Gast, L. F. L.

    2016-06-01

    The ability to measure benzene concentrations was added to the RIVM mobile DIAL system. In a ten-days campaign, it was used to measure benzene emissions in the Rijnmond, a heavily industrialised area in the South-west of the Netherlands with petrochemical industry, petrochemical products storage and the port of Rotterdam. On two of the ten days, benzene emissions were found. Combined with measurements of wind speed and wind direction, the Lidar measurements indicated the possible origins of these emissions. This makes the Lidar a valuable tool, augmenting the data collected at fixed monitoring stations.

  9. Studies on the mechanism of benzene toxicity.

    PubMed Central

    Snyder, R; Dimitriadis, E; Guy, R; Hu, P; Cooper, K; Bauer, H; Witz, G; Goldstein, B D

    1989-01-01

    Using the 59Fe uptake method of Lee et al. it was shown that erythropoiesis in female mice was inhibited following IP administration of benzene, hydroquinone, p-benzoquinone, and muconaldehyde. Toluene protected against the effects of benzene. Coadministration of phenol plus either hydroquinone or catechol resulted in greatly increased toxicity. The combination of metabolites most effective in reducing iron uptake was hydroquinone plus muconaldehyde. We have also shown that treating animals with benzene leads to the formation of adducts of bone marrow DNA as measured by the 32P-postlabeling technique. PMID:2792049

  10. Excited state of protonated benzene and toluene

    SciTech Connect

    Esteves-López, Natalia; Dedonder-Lardeux, Claude; Jouvet, Christophe

    2015-08-21

    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)].

  11. Exposure of hematopoietic stem cells to benzene or 1,4-benzoquinone induces gender-specific gene expression.

    PubMed

    Faiola, Brenda; Fuller, Elizabeth S; Wong, Victoria A; Pluta, Linda; Abernethy, Diane J; Rose, Jason; Recio, Leslie

    2004-01-01

    Chronic exposure to benzene results in progressive decline of hematopoietic function and may lead to the onset of various disorders, including aplastic anemia, myelodysplastic syndrome, and leukemia. Damage to macromolecules resulting from benzene metabolites and misrepair of DNA lesions may lead to changes in hematopoietic stem cells (HSCs) that give rise to leukemic clones. We have shown previously that male mice exposed to benzene by inhalation were significantly more susceptible to benzene-induced toxicities than females. Because HSCs are targets for benzene-induced cytotoxicity and genotoxicity, we investigated DNA damage responses in HSC from both genders of 129/SvJ mice after exposure to 1,4-benzoquinone (BQ) in vitro or benzene in vivo. 1,4-BQ is a highly reactive metabolite of benzene that can cause cellular damage by forming protein and DNA adducts and producing reactive oxygen species. HSCs cultured in the presence of 1,4-BQ for 24 hours showed a gender-independent, dose-dependent cytotoxic response. RNA isolated from 1,4-BQ-treated HSCs and HSCs from mice exposed to 100 ppm benzene by inhalation showed altered expression of apoptosis, DNA repair, cell cycle, and growth control genes compared with unexposed HSCs. Rad51, xpc, and mdm-2 transcript levels were increased in male but not female HSCs exposed to 1,4-BQ. Males exposed to benzene exhibited higher mRNA levels for xpc, ku80, ccng, and wig1. These gene expression differences may partially explain the gender disparity in benzene susceptibility. HSC culture systems such as the one used here will be useful for testing the hematotoxicity of various substances, including other benzene metabolites.

  12. 46 CFR 197.565 - Notifying personnel of benzene hazards.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 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 2012-10-01 2012-10-01 false Notifying personnel of benzene hazards. 197.565 Section... AND HEALTH STANDARDS GENERAL PROVISIONS Benzene § 197.565 Notifying personnel of benzene hazards....

  13. 46 CFR 197.565 - Notifying personnel of benzene hazards.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 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 2014-10-01 2014-10-01 false Notifying personnel of benzene hazards. 197.565 Section... AND HEALTH STANDARDS GENERAL PROVISIONS Benzene § 197.565 Notifying personnel of benzene hazards....

  14. 46 CFR 197.565 - Notifying personnel of benzene hazards.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 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 2011-10-01 2011-10-01 false Notifying personnel of benzene hazards. 197.565 Section... AND HEALTH STANDARDS GENERAL PROVISIONS Benzene § 197.565 Notifying personnel of benzene hazards....

  15. 46 CFR 197.565 - Notifying personnel of benzene hazards.

    Code of Federal Regulations, 2010 CFR

    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....

  16. 46 CFR 197.565 - Notifying personnel of benzene hazards.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 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 2013-10-01 2013-10-01 false Notifying personnel of benzene hazards. 197.565 Section... AND HEALTH STANDARDS GENERAL PROVISIONS Benzene § 197.565 Notifying personnel of benzene hazards....

  17. Tyrosine aminotransferase activity in the benzene intoxicated rat

    SciTech Connect

    Bong, M.; Michalska, A.; Laskowska-Klita, T.; Szymczyk, T.

    1985-01-01

    The toxic effect of hydrocarbon solvents on hepatic metabolism manifests itself by changes in the enzymatic pattern of blood serum. Changes in the activity of phosphatases as well as leucine aminopeptidase, glutamine aminotransferase, sorbitol dehydrogenase and ..gamma..-glutamyltransferase were observed in rats intoxicated with different fractions of benzene. Therefore it seemed reasonable to investigate the effect of benzene fraction of petroleum on cellular metabolism. The results of the present work concern the activity of tyrosine aminotransferase, the enzyme involved in catabolism of aromatic amino acid which is known to be under both hormonal and stress dependent control. Changes in tyrosine aminotransferase activity effect the level of tyrosine oxidation as well as the metabolic conversion of this amino acid into tyramine, tyroxin, adrenaline and noradrenaline.

  18. Theoretical study of transition-metal ions bound to benzene

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W., Jr.; Partridge, Harry; Langhoff, Stephen R.

    1992-01-01

    Theoretical binding energies are reported for all first-row and selected second-row transition metal ions (M+) bound to benzene. The calculations employ basis sets of at least double-zeta plus polarization quality and account for electron correlation using the modified coupled-pair functional method. While the bending is predominantly electrostatic, the binding energies are significantly increased by electron correlation, because the donation from the metal d orbitals to the benzene pi* orbitals is not well described at the self-consistent-field level. The uncertainties in the computed binding energies are estimated to be about 5 kcal/mol. Although the calculated and experimental binding energies generally agree to within their combined uncertainties, it is likely that the true binding energies lie in the lower portion of the experimental range. This is supported by the very good agreement between the theoretical and recent experimental binding energies for AgC6H6(+).

  19. EPR study of Gallium atoms in benzene

    SciTech Connect

    Howard, J.A.; Joly, H.A.; Mile, B.; Sutcliffe, R. )

    1991-09-05

    An EPR study of a Ga atom matrix isolated in benzene at 77 K has revealed the presence of a paramagnetic species with the magnetic parameters {alpha}{sub zz}(69) = 256 MHz, {alpha}{sub xx}(69) = 270 MHz, {alpha}{sub yy}(69) = 284 MHz, {alpha}{sub zz}(71) = 325 MHz, {alpha}{sub xx}(71) = 343 MHz, {alpha}{sub yy}(71) = 361 Mhz, g{sub zz} = 1.9970, g{approximately}{sub xx} = 1.9750, and g{sub yy} = 1.9350. These parameters are consistent with a trapped atom or a weak Ga-benzene complex that has had the degeneracy of the Ga p orbitals lifted by interaction with the benzene matrix. This contrasts with Al in benzene which gives a mononuclear monoligand complex, Al(C{sub 6}H{sub 6}), with quite strong bonding between the metal atom and the ligand.

  20. Oxidation Mechanisms of Toluene and Benzene

    NASA Technical Reports Server (NTRS)

    Bittker, David A.

    1995-01-01

    An expanded and improved version of a previously published benzene oxidation mechanism is presented and shown to model published experimental data fairly successfully. This benzene submodel is coupled to a modified version of a toluene oxidation submodel from the recent literature. This complete mechanism is shown to successfully model published experimental toluene oxidation data for a highly mixed flow reactor and for higher temperature ignition delay times in a shock tube. A comprehensive sensitivity analysis showing the most important reactions is presented for both the benzene and toluene reacting systems. The NASA Lewis toluene mechanism's modeling capability is found to be equivalent to that of the previously published mechanism which contains a somewhat different benzene submodel.

  1. Electromers of the benzene dimer radical cation.

    PubMed

    Błoch-Mechkour, Anna; Bally, Thomas

    2015-04-28

    The well-studied benzene dimer radical cation, which is prototypical for this class of species, has been reinvestigated computationally. Thereby it turned out that both the σ-hemibonded and the half-shifted sandwich structures of the benzene dimer cation, which had been independently proposed, represent stationary points on the B2PLYP-D potential energy surfaces. However, these structures belong to distinct electronic states, both of which are associated with potential surfaces that are very flat with regard to rotation of the two benzene rings in an opposite sense relative to each other. The surfaces of these two "electromers" of the benzene dimer cation are separated by only 3-4 kcal mol(-1) and do not intersect along the rotation coordinate, which represents a rather unique electronic structure situation. When moving on either of the two surfaces the title complex is an extremely fluxional species, in spite of its being bound by over 20 kcal mol(-1).

  2. Active airborne contamination control using electrophoresis

    SciTech Connect

    Veatch, B.D.

    1994-06-01

    In spite of our best efforts, radioactive airborne contamination continues to be a formidable problem at many of the Department of Energy (DOE) weapons complex sites. For workers that must enter areas with high levels of airborne contamination, personnel protective equipment (PPE) can become highly restrictive, greatly diminishing productivity. Rather than require even more restrictive PPE for personnel in some situations, the Rocky Flats Plant (RFP) is actively researching and developing methods to aggressively combat airborne contamination hazards using electrophoretic technology. With appropriate equipment, airborne particulates can be effectively removed and collected for disposal in one simple process. The equipment needed to implement electrophoresis is relatively inexpensive, highly reliable, and very compact. Once airborne contamination levels are reduced, less PPE is required and a significant cost savings may be realized through decreased waste and maximized productivity. Preliminary ``cold,`` or non-radioactive, testing results at the RFP have shown the technology to be effective on a reasonable scale, with several potential benefits and an abundance of applications.

  3. Photoionization spectrum of liquid benzene

    SciTech Connect

    Saik, V. O.; Lipsky, S. )

    1994-11-17

    The photocurrent from neat liquid benzene has been studied for excitation energies from threshold to 10.3 eV and for externally applied electric fields from 1 to 50 kV/cm. Using a power law fit to the energy dependence of the threshold current, an onset of [epsilon][sub t] = 7.65 [+-] 0.1 eV has been obtained. The field dependence was fit to an exponential radial probability density for thermalized ion-pair separation distances with an average separation distance of [r] = 23 [+-] 2 A at an excitation energy, [epsilon] of 8.86 eV (1.2 eV above threshold). Photocurrent was too weak to establish a dependence of [r] on excitation energy. The quantum yield for photocurrent at 8.86 eV was determined by comparison with the photocurrent from TMPD in 2,2,4-trimethylpentane (isooctane) to be 6.5 [times] 10[sup [minus]4] at zero field. From this, the intrinsic molecular ionization probability at [epsilon] = 8.86 eV was determined to be 0.6 [+-] 0.3. 30 refs., 5 figs.

  4. Benzene-derived carbon nanothreads

    NASA Astrophysics Data System (ADS)

    Fitzgibbons, Thomas C.; Guthrie, Malcolm; Xu, En-Shi; Crespi, Vincent H.; Davidowski, Stephen K.; Cody, George D.; Alem, Nasim; Badding, John V.

    2015-01-01

    Low-dimensional carbon nanomaterials such as fullerenes, nanotubes, graphene and diamondoids have extraordinary physical and chemical properties. Compression-induced polymerization of aromatic molecules could provide a viable synthetic route to ordered carbon nanomaterials, but despite almost a century of study this approach has produced only amorphous products. Here we report recovery to ambient pressure of macroscopic quantities of a crystalline one- dimensional sp3 carbon nanomaterial formed by high-pressure solid-state reaction of benzene. X-ray and neutron diffraction, Raman spectroscopy, solid-state NMR, transmission electron microscopy and first-principles calculations reveal close- packed bundles of subnanometre-diameter sp3-bonded carbon threads capped with hydrogen, crystalline in two dimensions and short-range ordered in the third. These nanothreads promise extraordinary properties such as strength and stiffness higher than that of sp2 carbon nanotubes or conven tional high-strength polymers. They may be the first member of a new class of ordered sp3 nanomaterials synthesized by kinetic control of high-pressure solid-state reactions.

  5. Benzene-derived carbon nanothreads.

    PubMed

    Fitzgibbons, Thomas C; Guthrie, Malcolm; Xu, En-shi; Crespi, Vincent H; Davidowski, Stephen K; Cody, George D; Alem, Nasim; Badding, John V

    2015-01-01

    Low-dimensional carbon nanomaterials such as fullerenes, nanotubes, graphene and diamondoids have extraordinary physical and chemical properties. Compression-induced polymerization of aromatic molecules could provide a viable synthetic route to ordered carbon nanomaterials, but despite almost a century of study this approach has produced only amorphous products. Here we report recovery to ambient pressure of macroscopic quantities of a crystalline one- dimensional sp(3) carbon nanomaterial formed by high-pressure solid-state reaction of benzene. X-ray and neutron diffraction, Raman spectroscopy, solid-state NMR, transmission electron microscopy and first-principles calculations reveal close- packed bundles of subnanometre-diameter sp(3)-bonded carbon threads capped with hydrogen, crystalline in two dimensions and short-range ordered in the third. These nanothreads promise extraordinary properties such as strength and stiffness higher than that of sp(2) carbon nanotubes or conventional high-strength polymers. They may be the first member of a new class of ordered sp(3) nanomaterials synthesized by kinetic control of high-pressure solid-state reactions.

  6. Meeting benzene regulations through new desalting applications

    SciTech Connect

    Schantz, S.; Garcia, J.; Mourer, J.

    1995-09-01

    In the past, the industry has studied the impact of changing desalting variables on total oil undercarry. With the advent of the NESHAP regulations, benzene measurement is performed on a scheduled basis but not observed as desalting variables are changed and optimized. Benzene is normally present in crude at concentrations ranging from 0.1 to 0.6 ppm, and it is extremely soluble in water: up to 1,800 mg/l at standard temperature and pressure. The NESHAP benzene standard has created a strong interest in real-time experiments to clarify the factors that affect benzene concentrations in desalter effluent water. The work reported on in this paper attempts to answer the following questions: can the benzene concentration in desalter wastewater be determined reliably in real time so that desalter operational parameters can be tuned to minimize this concentration; how do changes in four key desalter variables--temperature, chemical dosage, wash water rate, and mix-valve pressure differential, affect benzene concentration in the effluent water?

  7. Benzene toxicity: emphasis on cytosolic dihydrodiol dehydrogenases

    SciTech Connect

    Bolcsak, L.E.

    1982-01-01

    Blood dyscrasias such as leukopenia and anemia have been clearly identified as consequences of chronic benzene exposure. The metabolites, phenol, catechol, and hydroquinone produced inhibition of /sup 59/Fe uptake in mice which followed the same time course as that produced by benzene. The inhibitor of benzene oxidation, 3-amino-1,2,4-triazole, mitigated the inhibitory effects of benzene and phenol only. These data support the contention that benzene toxicity is mediated by a metabolite and suggest that the toxicity of phenol is a consequence of its metabolism to hydroquinone and that the route of metabolism to catechol may also contribute to the production of toxic metabolite(s). The properties of mouse liver cytosolic dihydrodiol dehydrogenases were examined. These enzymes catalyze the NADP/sup +/-dependent oxidation of trans-1,2-dihydro-1,2-dihydroxybenzene (BDD) to catechol, a possible toxic metabolite of benzene produced via this metabolic route. Four distinct dihydrodiol dehydrogenases (DD1, DD2, DD3, and DD4) were purified to apparent homogeneity as judged by SDS polyacrylamide gel electrophoresis and isoelectric focusing. DD1 appeared to be identical to the major ketone reductase and 17..beta..-hydroxysteroid dehydrogenase activity in the liver. DD2 exhibited aldehyde reductase activity. DD3 and DD4 oxidized 17..beta..-hydroxysteroids, but no carbonyl reductase activity was detected. These relationships between BDD dehydrogenases and carbonyl reductase and/or 17..beta..-hydroxysteroid dehydrogenase activities were supported by several lines of evidence.

  8. Benzene dynamics and biodegradation in alluvial aquifers affected by river fluctuations.

    PubMed

    Batlle-Aguilar, J; Morasch, B; Hunkeler, D; Brouyère, S

    2014-01-01

    The spatial distribution and temporal dynamics of a benzene plume in an alluvial aquifer strongly affected by river fluctuations was studied. Benzene concentrations, aquifer geochemistry datasets, past river morphology, and benzene degradation rates estimated in situ using stable carbon isotope enrichment were analyzed in concert with aquifer heterogeneity and river fluctuations. Geochemistry data demonstrated that benzene biodegradation was on-going under sulfate reducing conditions. Long-term monitoring of hydraulic heads and characterization of the alluvial aquifer formed the basis of a detailed modeled image of aquifer heterogeneity. Hydraulic conductivity was found to strongly correlate with benzene degradation, indicating that low hydraulic conductivity areas are capable of sustaining benzene anaerobic biodegradation provided the electron acceptor (SO4 (2-) ) does not become rate limiting. Modeling results demonstrated that the groundwater flux direction is reversed on annual basis when the river level rises up to 2 m, thereby forcing the infiltration of oxygenated surface water into the aquifer. The mobilization state of metal trace elements such as Zn, Cd, and As present in the aquifer predominantly depended on the strong potential gradient within the plume. However, infiltration of oxygenated water was found to trigger a change from strongly reducing to oxic conditions near the river, causing mobilization of previously immobile metal species and vice versa. MNA appears to be an appropriate remediation strategy in this type of dynamic environment provided that aquifer characterization and targeted monitoring of redox conditions are adequate and electron acceptors remain available until concentrations of toxic compounds reduce to acceptable levels.

  9. Lymphohaematopoietic malignancies and quantitative estimates of exposure to benzene in Canadian petroleum distribution workers.

    PubMed Central

    Schnatter, A R; Armstrong, T W; Nicolich, M J; Thompson, F S; Katz, A M; Huebner, W W; Pearlman, E D

    1996-01-01

    OBJECTIVE: To evaluate the relation between mortality from lymphohaematopoietic cancer and long term, low level exposures to benzene among male petroleum distribution workers. METHODS: This nested case control study identified all fatal cases of lymphohaematopoietic cancer among a previously studied cohort. Of the 29 cases, 14 had leukaemia, seven multiple myeloma, and eight non-Hodgkin's lymphoma. A four to one matching ratio was used to select a stratified sample of controls from the same cohort, controlling for year of birth and time at risk. Industrial hygienists estimated workplace exposures for benzene and total hydrocarbons, without knowledge of case or control status, for combinations of job, location, and era represented in all work histories. Average daily benzene concentrations ranged from 0.01 to 6.2 parts per million (ppm) for all jobs. Company medical records were used to abstract information on other potential confounders such as cigarette smoking, although the data were incomplete. Odds ratios (ORs) were calculated with conditional logistic regression techniques for several exposure variables. RESULTS: Risks of leukaemia, non-Hodgkin's lymphoma, and multiple myeloma were not associated with increasing cumulative exposure to benzene or total hydrocarbons. For leukaemia, the logistic regression model predicted an OR of 1.002 (P < 0.77) for each ppm-y of exposure to benzene. Duration of exposure to benzene was more closely associated with risk of leukaemia than other exposure variables. It was not possible to completely control for other risk factors, although there was suggestive evidence that smoking and a family history of cancer may have played a part in the risk of leukaemia. CONCLUSION: This study did not show a relation between lymphohaematopoietic cancer and long term, low level exposures to benzene. The power of the study to detect low-such as twofold-risks was limited. Thus, further study on exposures to benzene in this concentration range

  10. Cyberinfrastructure for Airborne Sensor Webs

    NASA Technical Reports Server (NTRS)

    Freudinger, Lawrence C.

    2009-01-01

    Since 2004 the NASA Airborne Science Program has been prototyping and using infrastructure that enables researchers to interact with each other and with their instruments via network communications. This infrastructure uses satellite links and an evolving suite of applications and services that leverage open-source software. The use of these tools has increased near-real-time situational awareness during field operations, resulting in productivity improvements and the collection of better data. This paper describes the high-level system architecture and major components, with example highlights from the use of the infrastructure. The paper concludes with a discussion of ongoing efforts to transition to operational status.

  11. Effects of Temperature, Oxygen Level, Ionic Strength, and pH on the Reaction of Benzene with Hydroxyl Radicals at the Air-Water Interface in Comparison to the Bulk Aqueous Phase.

    PubMed

    Heath, Aubrey A; Valsaraj, Kalliat T

    2015-08-01

    Atmospheric aerosols (e.g., fog droplets) are complex, multiphase mediums. Depending on location, time of day, and/or air mass source, there can be considerable variability within these droplets, relating to temperature, pH, and ionic strength. Due to the droplets' inherently small size, the reactions that occur within these droplets are determined by bulk aqueous phase and air-water interfacial conditions. In this study, the reaction of benzene and hydroxyl radicals is examined kinetically in a thin-film flow-tube reactor. By varying the aqueous volume (e.g., film thickness) along the length of the reactor, both bulk and interfacial reaction rates are measured from a single system. Temperature, pH, and ionic strength are varied to model conditions typical of fog events. Oxygen-poor conditions are measured to study oxygen's overall effect on the reaction pathway. Initial rate activation energies and the bulk aqueous phase and interfacial contributions to the overall rate constant are also obtained. PMID:26158391

  12. Effects of Temperature, Oxygen Level, Ionic Strength, and pH on the Reaction of Benzene with Hydroxyl Radicals at the Air-Water Interface in Comparison to the Bulk Aqueous Phase.

    PubMed

    Heath, Aubrey A; Valsaraj, Kalliat T

    2015-08-01

    Atmospheric aerosols (e.g., fog droplets) are complex, multiphase mediums. Depending on location, time of day, and/or air mass source, there can be considerable variability within these droplets, relating to temperature, pH, and ionic strength. Due to the droplets' inherently small size, the reactions that occur within these droplets are determined by bulk aqueous phase and air-water interfacial conditions. In this study, the reaction of benzene and hydroxyl radicals is examined kinetically in a thin-film flow-tube reactor. By varying the aqueous volume (e.g., film thickness) along the length of the reactor, both bulk and interfacial reaction rates are measured from a single system. Temperature, pH, and ionic strength are varied to model conditions typical of fog events. Oxygen-poor conditions are measured to study oxygen's overall effect on the reaction pathway. Initial rate activation energies and the bulk aqueous phase and interfacial contributions to the overall rate constant are also obtained.

  13. Airborne data acquisition techniques

    SciTech Connect

    Arro, A.A.

    1980-01-01

    The introduction of standards on acceptable procedures for assessing building heat loss has created a dilemma for the contractor performing airborne thermographic surveys. These standards impose specifications on instrumentation, data acquisition, recording, interpretation, and presentation. Under the standard, the contractor has both the obligation of compliance and the requirement of offering his services at a reasonable price. This paper discusses the various aspects of data acquisition for airborne thermographic surveys and various techniques to reduce the costs of this operation. These techniques include the calculation of flight parameters for economical data acquisition, the selection and use of maps for mission planning, and the use of meteorological forecasts for flight scheduling and the actual execution of the mission. The proper consideration of these factors will result in a cost effective data acquisition and will place the contractor in a very competitive position in offering airborne thermographic survey services.

  14. Influence of Benzene on the Optical Properties of Titan Haze Laboratory Analogs in the Mid-Visible

    NASA Technical Reports Server (NTRS)

    Yoon, Y. Heidi; Trainer, Melissa G.; Tolbert, Margaret A.

    2012-01-01

    The Cassini Ion and Neutral Mass Spectrometer (Waite, Jr., et al., 2007) and the Composite Infrared Spectrometer (Coustenis, A., et al., 2007) have detected benzene in the upper atmosphere and stratosphere of Titan. Photochemical reactions involving benzene in Titan's atmosphere may influence polycyclic aromatic hydrocarbon formation, aerosol formation, and the radiative balance of Titan's atmosphere. We measure the effect of benzene on the optical properties of Titan analog particles in the laboratory. Using cavity ring-down aerosol extinction spectroscopy, we determine the real and imaginary refractive index at 532 nm of particles formed by benzene photolysis and Titan analog particles formed with ppm-levels of benzene. These studies are compared to the previous study by Hasenkopf, et a1. (2010) of Titan analog particles formed by methane photolysis.

  15. Green tea attenuates benzene-induced oxidative stress in pump workers.

    PubMed

    Emara, Ashraf M; El-Bahrawy, Hoda

    2008-01-01

    Workers exposed to benzene frequently suffer from toxicities of the bone marrow as well as the central nervous, immune, and reproductive systems. This toxicity most likely is a result of the oxidative metabolism of benzene to reactive products. As green tea possesses antioxidant effects, the objective of this study was to examine any amelioration of benzene-induced oxidative stress in pump workers drinking 6 cups (150 ml/cup) of freshly prepared tea daily. Sixty male non-smoking subjects, divided into four groups: no benzene exposure/no green tea; no exposure/tea; exposure/no tea; and, exposure/tea, were monitored after a 6 mo period. On the final day of the study, urine samples were collected for analyses of benzene, trans-trans muconic acid, and phenol. Blood was also collected at this time; plasma was assayed for total antioxidant activity, malondialdehyde (MDA), and glutathione (GSH) while erythrocytes were analyzed for activity of antioxidant enzymes glutathione peroxidase (GSHPX), superoxide dismutase (SOD), and catalase. The results demonstrated that urinary levels of benzene, trans-trans muconic acid, and phenol were elevated in all pump workers, and that this elevation was mitigated by consumption of green tea. The benzene exposures also led to significant reductions in plasma GSH levels and erythrocyte antioxidant enzyme activities; these effects were abrogated (to near-control levels) by the tea. Interestingly, among control subjects, tea ingestion itself caused significant increases in both GSHPX and catalase activities. Unlike with the other plasma parameters, while the benzene exposures also significantly increased plasma MDA levels and decreased total antioxidant activity, tea ingestion did not cause a near-total reversion to control values; the effects on these two endpoints were more like those noted with the urine parameters (mitigation, not abrogation). These studies demonstrate that drinking green tea during benzene exposure can reduce several

  16. Airborne oceanographic lidar system

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Specifications and preliminary design of an Airborne Oceanographic Lidar (AOL) system, which is to be constructed for installation and used on a NASA Wallops Flight Center (WFC) C-54 research aircraft, are reported. The AOL system is to provide an airborne facility for use by various government agencies to demonstrate the utility and practicality of hardware of this type in the wide area collection of oceanographic data on an operational basis. System measurement and performance requirements are presented, followed by a description of the conceptual system approach and the considerations attendant to its development. System performance calculations are addressed, and the system specifications and preliminary design are presented and discussed.

  17. Airborne rain mapping radar

    NASA Technical Reports Server (NTRS)

    Wilson, W. J.; Parks, G. S.; Li, F. K.; Im, K. E.; Howard, R. J.

    1988-01-01

    An airborne scanning radar system for remote rain mapping is described. The airborne rain mapping radar is composed of two radar frequency channels at 13.8 and 24.1 GHz. The radar is proposed to scan its antenna beam over + or - 20 deg from the antenna boresight; have a swath width of 7 km; a horizontal spatial resolution at nadir of about 500 m; and a range resolution of 120 m. The radar is designed to be applicable for retrieving rainfall rates from 0.1-60 mm/hr at the earth's surface, and for measuring linear polarization signatures and raindrop's fall velocity.

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

    SciTech Connect

    Gandarias, J.M. de; Echevarria, E.; Martinez-Millan, L.; Casis, L.; Martinez-Garcia, F.

    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.

  19. NASA Airborne Lidar July 1991

    Atmospheric Science Data Center

    2016-05-26

    NASA Airborne Lidar July 1991 Data from the 1991 NASA Langley Airborne Lidar flights following the eruption of Pinatubo in July ... and Osborn [1992a, 1992b]. Project Title:  NASA Airborne Lidar Discipline:  Field Campaigns ...

  20. NASA Airborne Lidar May 1992

    Atmospheric Science Data Center

    2016-05-26

    NASA Airborne Lidar May 1992 An airborne Nd:YAG (532 nm) lidar was operated by the NASA Langley Research Center about a year following the June 1991 eruption of ... Osborn [1992a, 1992b].  Project Title:  NASA Airborne Lidar Discipline:  Field Campaigns ...

  1. Adsorptive treatment of shale-tar benzene

    SciTech Connect

    Alekseeva, R.V.; Kharitonova, L.K.

    1984-01-01

    This article describes the use of adsorbents to remove thiophene from benzene. A nickel-substituted type X zeolite has been developed as a thiophene-selective adsorbent. Unsaturates were removed from the benzene by using A-4M microbead adsorbent. The optimal treating conditions were selected in pilot-unit tests at a pressure p=2 MPa, using a mathematically designed experiment. The A-4M adsorbent can be used repeatedly, with a service life of 6 months. The clarified benzene was treated at room temperature, passing the benzene at a velocity of 0.3 cm/min through a bed of NiCaX, which adsorbs unsaturated hydrocarbons along with the thiophene. The final stage in the treatment is the removal of saturated hydrocarbons from the benzene on commercial CaA zeolite in the vapor phase at 100/sup 0/C with a feed velocity of 0.3 cm/min. The hydrocarbons were desorbed from the void spaces of the zeolite with n-pentane, subsequently removing the desorbent by conventional fractionation.

  2. Study of gaseous benzene effects upon A549 lung epithelial cells using a novel exposure system.

    PubMed

    Mascelloni, Massimiliano; Delgado-Saborit, Juana Maria; Hodges, Nikolas J; Harrison, Roy M

    2015-08-19

    Volatile organic compounds (VOCs) are ubiquitous pollutants known to be present in both indoor and outdoor air arising from various sources. Indoor exposure has increasingly become a major cause of concern due to the effects that such pollutants can have on health. Benzene, along with toluene, is one of the main components of the VOC mixture and is a known carcinogen due to its genotoxic effects. The aim of this study was to test the feasibility of an in vitro model to study the short-term effects of exposure of lung cells to airborne benzene. We studied the effects of exposure on DNA and the production of reactive oxygen species (ROS) in A549 cells, exposed to various concentrations of benzene (0.03; 0.1; 0.3 ppm) in gaseous form using a custom designed cell exposure chamber. Results showed a concentration-dependent increase of DNA breaks and an increase of ROS production, confirming the feasibility of the experimental procedure and validating the model for further in vitro studies of exposure to other VOCs.

  3. Airborne Fraunhofer Line Discriminator

    NASA Technical Reports Server (NTRS)

    Gabriel, F. C.; Markle, D. A.

    1969-01-01

    Airborne Fraunhofer Line Discriminator enables prospecting for fluorescent materials, hydrography with fluorescent dyes, and plant studies based on fluorescence of chlorophyll. Optical unit design is the coincidence of Fraunhofer lines in the solar spectrum occurring at the characteristic wavelengths of some fluorescent materials.

  4. Recognizing Airborne Hazards.

    ERIC Educational Resources Information Center

    Schneider, Christian M.

    1990-01-01

    The heating, ventilating, and air conditioning (HVAC) systems in older buildings often do not adequately handle air-borne contaminants. Outlines a three-stage Indoor Air Quality (IAQ) assessment and describes a case in point at a Pittsburgh, Pennsylvania, school. (MLF)

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

    PubMed

    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

  6. Occurrence of benzene as a heat-induced contaminant of carrot juice for babies in a general survey of beverages.

    PubMed

    Lachenmeier, Dirk W; Reusch, Helmut; Sproll, Constanze; Schoeberl, Kerstin; Kuballa, Thomas

    2008-10-01

    A survey of benzene contamination of 451 beverage samples, using headspace sampling combined with gas chromatography and mass spectrometry (HS-GC/MS) with a quantification limit of 0.13 microg l(-1), was conducted. Artefactual benzene formation during headspace sampling was excluded by gentle heating at 50 degrees C only and adjustment of sample pH to 10. The incidence of benzene contamination in soft drinks, beverages for babies, alcopops and beer-mixed drinks was relatively low, with average concentrations below the EU drinking-water limit of 1 microg l(-1). Significantly higher concentrations were only found in carrot juice, with the highest levels in carrot juice specifically intended for infants. About 94% of 33 carrot juice for infants had detectable benzene levels, with an average concentration of 1.86 +/- 1.05 microg l(-1). Benzene contamination of beverages was significantly correlated to iron and copper concentrations, which act as catalyst in benzene formation. The formation of benzene in carrot juice was predominantly caused by a heat-induced mechanism, which explains the higher levels in infant carrot juices that are subject to higher heat-treatment to exclude microbiological contamination. PMID:18608484

  7. International Symposium on Airborne Geophysics

    NASA Astrophysics Data System (ADS)

    Mogi, Toru; Ito, Hisatoshi; Kaieda, Hideshi; Kusunoki, Kenichiro; Saltus, Richard W.; Fitterman, David V.; Okuma, Shigeo; Nakatsuka, Tadashi

    2006-05-01

    Airborne geophysics can be defined as the measurement of Earth properties from sensors in the sky. The airborne measurement platform is usually a traditional fixed-wing airplane or helicopter, but could also include lighter-than-air craft, unmanned drones, or other specialty craft. The earliest history of airborne geophysics includes kite and hot-air balloon experiments. However, modern airborne geophysics dates from the mid-1940s when military submarine-hunting magnetometers were first used to map variations in the Earth's magnetic field. The current gamut of airborne geophysical techniques spans a broad range, including potential fields (both gravity and magnetics), electromagnetics (EM), radiometrics, spectral imaging, and thermal imaging.

  8. Modulation of the metabolism of airborne pollutants by glucoraphanin-rich and sulforaphane-rich broccoli sprout beverages in Qidong, China

    PubMed Central

    Kensler, Thomas W.; Ng, Derek; Carmella, Steven G.; Chen, Menglan; Jacobson, Lisa P.; Muñoz, Alvaro; Egner, Patricia A.; Chen, Jian Guo; Qian, Geng Sun; Chen, Tao Yang; Fahey, Jed W.; Talalay, Paul; Groopman, John D.; Yuan, Jian-Min; Hecht, Stephen S.

    2012-01-01

    Epidemiological evidence has suggested that consumption of a diet rich in cruciferous vegetables reduces the risk of several types of cancers and chronic degenerative diseases. In particular, broccoli sprouts are a convenient and rich source of the glucosinolate, glucoraphanin, which can release the chemopreventive agent, sulforaphane, an inducer of glutathione S-transferases. Two broccoli sprout-derived beverages, one sulforaphane-rich (SFR) and the other glucoraphanin-rich (GRR), were evaluated for pharmacodynamic action in a crossover clinical trial design. Study participants were recruited from the farming community of He Zuo Township, Qidong, China, previously documented to have a high incidence of hepatocellular carcinoma with concomitant exposures to aflatoxin and more recently characterized with exposures to substantive levels of airborne pollutants. Fifty healthy participants were randomized into two treatment arms. The study protocol was as follows: a 5 days run-in period, a 7 days administration of beverage, a 5 days washout period and a 7 days administration of the opposite beverage. Urinary excretion of the mercapturic acids of acrolein, crotonaldehyde, ethylene oxide and benzene were measured both pre- and postinterventions using liquid chromatography tandem mass spectrometry. Statistically significant increases of 20–50% in the levels of excretion of glutathione-derived conjugates of acrolein, crotonaldehyde and benzene were seen in individuals receiving SFR, GRR or both compared with their preintervention baseline values. No significant differences were seen between the effects of SFR versus GRR. Intervention with broccoli sprouts may enhance detoxication of airborne pollutants and attenuate their associated health risks. PMID:22045030

  9. Personal benzene vapor detection device. Final report

    SciTech Connect

    Glatkowski, P.; Druy, M.

    1992-07-01

    A badge was developed as a personal vapor detector to record the cumulative exposure of an individual to benzene vapor. The badge consisted of an optical fiber, small sections of which were coated with a membrane specific for the adsorption of benzene vapor. Membranes made of polyethylene and nylon, and filled with zeolite were applied to a silver halide fiber. Following exposure, the fiber was subjected to Fourier Transform Infrared (FTIR) spectrometry. The coating successfully retained the benzene vapor for several days. A concentration of 100,000 parts per million (ppm) could be detected. Concentrations of dichlorobenzene of 80,000ppm were also detected. Unique absorbance peaks were used to distinguish the two compounds. It was possible to reuse the sensor. However, the desired detectability range of 1 to 100ppm was not met.

  10. Photoreactivation in Airborne Mycobacterium parafortuitum

    PubMed Central

    Peccia, Jordan; Hernandez, Mark

    2001-01-01

    Photoreactivation was observed in airborne Mycobacterium parafortuitum exposed concurrently to UV radiation (254 nm) and visible light. Photoreactivation rates of airborne cells increased with increasing relative humidity (RH) and decreased with increasing UV dose. Under a constant UV dose with visible light absent, the UV inactivation rate of airborne M. parafortuitum cells decreased by a factor of 4 as RH increased from 40 to 95%; however, under identical conditions with visible light present, the UV inactivation rate of airborne cells decreased only by a factor of 2. When irradiated in the absence of visible light, cellular cyclobutane thymine dimer content of UV-irradiated airborne M. parafortuitum and Serratia marcescens increased in response to RH increases. Results suggest that, unlike in waterborne bacteria, cyclobutane thymine dimers are not the most significant form of UV-induced DNA damage incurred by airborne bacteria and that the distribution of DNA photoproducts incorporated into UV-irradiated airborne cells is a function of RH. PMID:11526027

  11. Health effects of benzene exposure among children following a flaring incident at the British Petroleum Refinery in Texas City.

    PubMed

    D'Andrea, Mark A; Reddy, G Kesava

    2014-02-01

    Human exposure to benzene is associated with multiple adverse health effects leading to hematological malignancies. The objective of this retrospective study was to evaluate the health consequences of benzene exposure in children following a flaring incident at the British petroleum (BP) refinery in Texas City, Texas. The study included children aged <17 years who had been exposed and unexposed to benzene. Using medical charts, clinical data including white blood cell (WBC) counts, platelets counts, hemoglobin, hematocrit, blood urea nitrogen (BUN), creatinine, alkaline phosphatase (ALP), aspartate amino transferase (AST), alanine amino transferase (ALT), and somatic symptom complaints by the children exposed to benzene were reviewed and analyzed. A total of 312 subjects (benzene exposed, n = 157 and unexposed, n = 155) were included. Hematologic analysis showed that WBC counts were significantly decreased in benzene-exposed children compared with the unexposed children (6.8 ± 2.1 versus 7.3 ± 1.7, P = .022). Conversely, platelet (X 10(3) per μL) counts were increased significantly in the benzene-exposed group compared with the unexposed group (278.4 ± 59.9 versus 261.6 ± 51.7, P = .005). Similarly, benzene-exposed children had significantly higher levels of ALP (183.7± 95.6 versus 165 ± 70.3 IU/L, P = .04), AST (23.6 ± 15.3 versus 20.5 ± 5.5 IU/L, P = .015), and ALT (19.2 ± 7.8 versus 16.9 ± 6.9 IU/L, P = .005) compared with the unexposed children. Together, the results of the study reveal that children exposed to benzene experienced significantly altered blood profiles, liver enzymes, and somatic symptoms indicating that children exposed to benzene are at a higher risk of developing hepatic or blood related disorders.

  12. Gas phase nitrosation of substituted benzenes

    NASA Astrophysics Data System (ADS)

    Dechamps, Noémie; Gerbaux, Pascal; Flammang, Robert; Bouchoux, Guy; Nam, Pham-Cam; Nguyen, Minh-Tho

    2004-03-01

    Using a combination of tandem mass spectrometric experiments (ion-molecule reactions, collisional activation, neutralization-reionization, MS/MS/MS) and theoretical calculations, protonated substituted benzenes are demonstrated to readily react with neutral t-butyl nitrite by the formation of stable complexes linking ionized nitric oxide to the benzene derivatives. The overall process is proposed to involve the concomitant elimination of neutral 2-methyl-2-propanol. Proton-bound dimers are proposed to intervene as the key-intermediates in these reactions, which also competitively produce protonated t-butyl nitrite. All the experiments were performed in a single hybrid tandem mass spectrometer of sector-quadrupole-sector configuration.

  13. Polyfunctional catalyst for processiing benzene fractions

    SciTech Connect

    G. Byakov; B.D. Zubitskii; B.G. Tryasunov; I.Ya. Petrov

    2009-05-15

    A by-product of the coke industry is a raw benzene fraction benzene- 1 which may serve as for catalytic processes. The paper reports a study on the influence of the composition and temperatures on the activity and selectivity of NiO-V{sub 2}O{sub 6}-MoO{sub 3}/{gamma}-Al{sub 2}O{sub 3} catalysts and the corresponding binary and tertiary subsystems are studied by a pulse method in model reactions; the hydrodealkylating of toluene and the hydrodesulfurizing of thioprhene. The optimal catalyst composition is established. The new catalyst is compared with industrial catalysts.

  14. The pyrolysis of toluene and ethyl benzene

    NASA Technical Reports Server (NTRS)

    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).

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

    PubMed

    Philbrook, Nicola A; Winn, Louise M

    2015-11-15

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

  16. Inter-agency Working Group for Airborne Data and Telemetry Systems (IWGADTS)

    NASA Technical Reports Server (NTRS)

    Webster, Chris; Freudinge, Lawrence; Sorenson, Carl; Myers, Jeff; Sullivan, Don; Oolman, Larry

    2009-01-01

    The Interagency Coordinating Committee for Airborne Geosciences Research and Applications (ICCAGRA) was established to improve cooperation and communication among agencies sponsoring airborne platforms and instruments for research and applications, and to serve as a resource for senior level management on airborne geosciences issues. The Interagency Working Group for Airborne Data and Telecommunications Systems (IWGADTS) is a subgroup to ICCAGRA for the purpose of developing recommendations leading to increased interoperability among airborne platforms and instrument payloads, producing increased synergy among research programs with similar goals, and enabling the suborbital layer of the Global Earth Observing System of Systems.

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

    PubMed Central

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

    2016-01-01

    Background Benzene is a known occupational carcinogen associated with increased risk of hematologic cancers, but the relationships between quantity of passive benzene exposure through residential proximity to toxic release sites, duration of exposure, lag time from exposure to cancer development, and lymphoma risk remain unclear. Methods We collected release data through the Environmental Protection Agency’s Toxics Release Inventory (TRI) from 1989 to 2003, which included location of benzene release sites, years when release occurred, and amount of release. We also collected data on incident cases of non-Hodgkin lymphoma (NHL) from the Georgia Comprehensive Cancer Registry (GCCR) for the years 1999–2008. We constructed distance-decay surrogate exposure metrics and Poisson and negative binomial regression models of NHL incidence to quantify associations between passive exposure to benzene and NHL risk and examined the impact of amount, duration of exposure, and lag time on cancer development. Akaike’s information criteria (AIC) were used to determine the scaling factors for benzene dispersion and exposure periods that best predicted NHL risk. Results Using a range of scaling factors and exposure periods, we found that increased levels of passive benzene exposure were associated with higher risk of NHL. The best fitting model, with a scaling factor of 4 kilometers (km) and exposure period of 1989–1993, showed that higher exposure levels were associated with increased NHL risk (Level 4 (1.1–160 kilograms (kg)) vs. Level 1: risk ratio 1.56 [1.44–1.68], Level 5 (>160 kg) vs. Level 1: 1.60 [1.48–1.74]). Conclusions Higher levels of passive benzene exposure are associated with increased NHL risk across various lag periods. Additional epidemiological studies are needed to refine these models and better quantify the expected total passive benzene exposure in areas surrounding release sites. PMID:26949112

  18. Personal reflections on 50 years of study of benzene toxicology.

    PubMed Central

    Parke, D V

    1996-01-01

    The metabolism of benzene is reviewed, and the objectives of a quantitative balance study begun in 1945 are outlined; problems of toxicology and metabolism research of some 50 years ago are considered. The quantitative metabolism of 14C-benzene in the rabbit is annotated and compared with that of unlabeled benzene quantified by nonisotopic methods. The anomalies of phenylmercapturic acid and trans-trans-muconic acid as metabolites of benzene are examined in detail by isotopic and nonisotopic methods; these compounds are true but minor metabolites of benzene. Oxygen radicals are involved in both the metabolism of benzene and its toxicity; the roles of CYP2E1, the redox cycling of quinone metabolites, glutathione oxidation, and oxidative stress in the unique radiomimetic, hematopoietic toxicity of benzene are discussed. Differences between the toxicity of benzene and the halobenzenes are related to fundamental differences in their electronic structures and to the consequent pathways of metabolic activation and detoxication. PMID:9118881

  19. Effect of carbon and hydrogen isotopic substitutions on the thermal diffusion of benzene

    SciTech Connect

    Rutherford, W.M.

    1989-01-01

    Measurements of the thermal diffusion factor of the benzene/carbon 13 substituted benzene pair and of the benzene/deuterated benzene pair are reported. The results show some interesting effects of mass distribution. (AIP)

  20. Solubilities of Toluene, Benzene and TCE in High-Biomass Systems

    SciTech Connect

    Barton, John W.; Vodraska, Christopher D; Flanary, Sandie A.; Davison, Brian H

    2008-01-01

    We report measurements of solubility limits for benzene, toluene, and TCE in systems that contain varying levels of biomass up to 0.13 g/mL. The solubility limit increased from 20 to 48 mM when biomass (in the form of yeast) was added to aqueous batch systems containing benzene. The toluene solubility limit increased from 4.9 to greater than 20 mM. For TCE, the solubility increased from 8 mM to more than 1000 mM. Solubility for TCE was most heavily impacted by biomass levels, changing by two orders of magnitude.

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

    PubMed

    Ntushelo, Khayalethu; Setshedi, Itumeleng

    2015-06-01

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

  2. Analysis of plasma microRNA expression profiles in a Chinese population occupationally exposed to benzene and in a population with chronic benzene poisoning

    PubMed Central

    Liu, Yang; Chen, Xianwen; Bian, Qian; Shi, Yuan; Liu, Qingdong; Ding, Lu; Zhang, Hengdong

    2016-01-01

    Background Circulating microRNA (miRNA) has attractive interests as a non-invasive biomarker of physiological and pathological conditions. Our study aimed to investigate the potential effects of chronic benzene poisoning (CBP) and benzene exposure on miRNA expression, and identify CBP-related miRNAs. Methods In the discovery stage, we used a microarray assay to detect the miRNA expression profiles among pooled plasma samples from ten CBP patients, ten healthy benzene-exposed individuals and ten non-benzene exposed individuals. Subsequently, we conducted an expanded validation of six candidate miRNAs in 27 CBP patients- low blood counts, 54 healthy benzene-exposed individuals and 54 non-exposed individuals. Moreover, we predicted the biological functions of putative target genes using a Gene Ontology (GO) function enrichment analysis and KEGG pathway analysis. Results In the discovery stage, compared with non-exposures, 36 and 12 miRNAs demonstrated at least a 1.0-fold differential expression in the CBP patients and the benzene exposures, respectively. And compared with benzene exposures, 58 miRNAs demonstrated at least a 1.0-fold differential expression in the CBP patients. In the expanded validation stage, compared with non-exposures as well as exposures, miR-24-3p and miR-221-3p were significantly up-regulated (1.99- and 2.06-fold for miR-24-3p, 2.19- and 3.93-fold for miR-221-3p, P<0.01) while miR-122-5p and miR-638 were significantly down-regulated (−3.45- and −2.60-fold for miR-122-5p, −1.82- and −3.20-fold for miR-638, P<0.001) in the CBP patients; compared with non-exposures, the plasma level of miR-638 was significantly up-regulated (1.38-fold, P<0.01) while the plasma levels miR-122-5p and miR-221-3p were significantly down-regulated (−0.85- and −1.74-fold, P<0.01) in the exposures, which were consistent with the results of microarray analysis. Conclusions The four indicated plasma miRNAs may be biomarkers of indicating responses to benzene

  3. Evaluation of genotoxic effects of benzene and its derivatives in workers of gas stations.

    PubMed

    Trevisan, Patrícia; da Silva, Juliane Nascimento; da Silva, Alessandra Pawelec; Rosa, Rafael Fabiano Machado; Paskulin, Giorgio Adriano; Thiesen, Flávia Valladão; de Oliveira, Ceres Andréia Vieira; Zen, Paulo Ricardo Gazzola

    2014-04-01

    The search for reliable biomarkers of human exposure to benzene and its derivatives is still subject of research. Many of the proposed biomarkers have limitations ranging from the low sensitivity to the wide variability of results. Thus, the aim of our study was to assess the frequencies of chromosomal abnormalities (CA) and sister chromatid exchanges (SCE) in workers of gas stations, with (cases, n = 19) and without (local controls, n = 6) risk of exposure to benzene and its derivatives, comparing them with the results from the general population (external controls, n = 38). The blood dosages of benzene, toluene, and xylenes were measured in all participants. Blood solvent levels were compared with the findings obtained in cytogenetic evaluation and a research protocol which included data of the workplace, lifestyle, and health of the individuals. We did not detect the presence of benzene and its derivatives and did not find chromosomal damage that may be associated with the gas station activity in cases. Moreover, although we found an association of increased SCE and the working time in the local controls, the values found for SCE are within normal limits. Thus, our evaluation of SCE and CA reflected the levels of benzene and its derivatives observed in the blood. We believe, therefore, that SCE and CA may actually constitute possible tests for the evaluation of these exposures. However, we believe that further studies, including individuals at risk, are important to confirm this assertion.

  4. [Air-borne disease].

    PubMed

    Lameiro Vilariño, Carmen; del Campo Pérez, Victor M; Alonso Bürger, Susana; Felpeto Nodar, Irene; Guimarey Pérez, Rosa; Pérez Alvarellos, Alberto

    2003-11-01

    Respiratory protection is a factor which worries nursing professionals who take care of patients susceptible of transmitting microorganisms through the air more as every day passes. This type of protection covers the use of surgical or hygienic masks against the transmission of infection by airborne drops to the use of highly effective masks or respirators against the transmission of airborne diseases such as tuberculosis or SARS, a recently discovered disease. The adequate choice of this protective device and its correct use are fundamental in order to have an effective protection for exposed personnel. The authors summarize the main protective respiratory devices used by health workers, their characteristics and degree of effectiveness, as well as the circumstances under which each device is indicated for use. PMID:14705591

  5. MLS airborne antenna research

    NASA Technical Reports Server (NTRS)

    Yu, C. L.; Burnside, W. D.

    1975-01-01

    The geometrical theory of diffraction was used to analyze the elevation plane pattern of on-aircraft antennas. The radiation patterns for basic elements (infinitesimal dipole, circumferential and axial slot) mounted on fuselage of various aircrafts with or without radome included were calculated and compared well with experimental results. Error phase plots were also presented. The effects of radiation patterns and error phase plots on the polarization selection for the MLS airborne antenna are discussed.

  6. Airborne forest fire research

    NASA Technical Reports Server (NTRS)

    Mattingly, G. S.

    1974-01-01

    The research relating to airborne fire fighting systems is reviewed to provide NASA/Langley Research Center with current information on the use of aircraft in forest fire operations, and to identify research requirements for future operations. A literature survey, interview of forest fire service personnel, analysis and synthesis of data from research reports and independent conclusions, and recommendations for future NASA-LRC programs are included.

  7. Formation of benzene in the interstellar medium

    PubMed Central

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

    2011-01-01

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

  8. Behavioral changes in mice following benzene inhalation.

    PubMed

    Evans, H L; Dempster, A M; Snyder, C A

    1981-01-01

    Although benzene is an important occupational health hazard and a carcinogen, the possibility that behavioral changes may forewarn of the later-occurring hematological changes has not been investigated. A time-sampling protocol was used to quantify the occurrence of 7 categories of behavior in the homecage following daily 6-hr exposures to two strains of adult mice (CD1 and C57BL/6J). The behavioral categories were stereotypic behavior, sleeping, resting, eating, grooming, locomotion, and fighting. The inhalation exposures were designed to reflect occupational exposure. Dynamic vapor exposure techniques in standard inhalation chambers were employed. Exposure to 300 or 900 ppm benzene increased the occurrence of eating and grooming and reduced the number of mice that were sleeping or resting. The responses to benzene of both the CD1 and the C57 strains were similar. The positive findings with benzene inhalation indicate the utility of behavioral investigations into the toxicology of inhaled organic solvents. The methods described herein illustrate an objective observation of animal behavior that is capable of documenting toxicity and of guiding detailed follow-up studies aimed at mechanism of action.

  9. IRIS TOXICOLOGICAL REVIEW OF BENZENE (NONCANCER EFFECTS)

    EPA Science Inventory

    Benzene, also known as benzol, is widely used as an industrial solvent, as an intermediate in chemical syntheses, and as a component of gasoline; hence, the potential for human exposure is great. The emphasis of this document is a discussion of the noncancer adverse healt...

  10. Formation of benzene in the interstellar medium.

    PubMed

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

    2011-01-11

    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 (C(6)H(6)) can be synthesized via the barrierless, exoergic reaction of the ethynyl radical and 1,3-butadiene, C(2)H + H(2)CCHCHCH(2) → C(6)H(6) + H, under single collision conditions. This reaction portrays the simplest representative of a reaction class in which aromatic molecules with a benzene core can be formed from acyclic precursors via barrierless reactions of ethynyl radicals with substituted 1,3-butadiene molecules. Unique gas-grain astrochemical models imply that this low-temperature route controls the synthesis of the very first aromatic ring from acyclic precursors in cold molecular clouds, such as in the Taurus Molecular Cloud. Rapid, subsequent barrierless reactions of benzene with ethynyl radicals can lead to naphthalene-like structures thus effectively propagating the ethynyl-radical mediated formation of aromatic molecules in the interstellar medium.

  11. Electroencephalographic findings in workers exposed to benzene.

    PubMed

    Kellerová, V

    1985-01-01

    Preventive EEG examination was carried out in 40 workers significantly exposed to benzene. The EEG findings were compared with those of a control group of 48 healthy persons, a group of 110 workers significantly exposed to toluene and xylene and a group of 236 workers exposed to vinyl chloride. The individuals exposed to benzene exhibited 22.5% of abnormal and 45% threshold findings, the abnormalities being episodic, diffuse or a combination of the two. The effect of benzene entailed a frequent (32.5%) occurrence of a characteristic frequency lability. Sleep phenomena were found in a total of 60% cases (37.5% cases reached stage 1 B3 while 15% reached stage 2 according to Roth [14]). The rapid onset of deeper sleep stages (in 30% cases) is considered typical for benzene exposure. The photic driving response often had an extended frequency range (a total of 61.1%, to beta frequencies only in 30.55%, to both beta and theta frequencies also in 30.55% of cases). The different EEG features characteristic of the neurotoxic action of various types of organic solvents make possible a more efficient diagnostics of the effects of these chemicals on the CNS. PMID:4086812

  12. 46 CFR 153.1060 - Benzene.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 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...

  13. 46 CFR 153.1060 - Benzene.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 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...

  14. Formation of Benzene in the Interstellar Medium

    NASA Technical Reports Server (NTRS)

    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.

  15. 46 CFR 153.1060 - Benzene.

    Code of Federal Regulations, 2010 CFR

    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...

  16. 46 CFR 153.1060 - Benzene.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 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...

  17. 46 CFR 153.1060 - Benzene.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 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...

  18. 40 CFR 721.1350 - Benzene, (1-methylethyl)(2-phenylethyl)-.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 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,...

  19. 40 CFR 721.1187 - Bis(imidoethylene) benzene.

    Code of Federal Regulations, 2010 CFR

    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...

  20. 40 CFR 721.10028 - Disubstituted benzene metal salts (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Disubstituted benzene metal salts... Specific Chemical Substances § 721.10028 Disubstituted benzene metal salts (generic). (a) Chemical... as disubstituted benzene metal salts (PMNs P-01-901 and P-01-902) are subject to reporting under...

  1. 40 CFR 721.1210 - Benzene, (2-chloroethoxy)-.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 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...

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

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 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,...

  3. 40 CFR 721.10028 - Disubstituted benzene metal salts (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Disubstituted benzene metal salts... Specific Chemical Substances § 721.10028 Disubstituted benzene metal salts (generic). (a) Chemical... as disubstituted benzene metal salts (PMNs P-01-901 and P-01-902) are subject to reporting under...

  4. 40 CFR 721.10028 - Disubstituted benzene metal salts (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Disubstituted benzene metal salts... Specific Chemical Substances § 721.10028 Disubstituted benzene metal salts (generic). (a) Chemical... as disubstituted benzene metal salts (PMNs P-01-901 and P-01-902) are subject to reporting under...

  5. 40 CFR 721.1187 - Bis(imidoethylene) benzene.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 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...

  6. 40 CFR 721.1210 - Benzene, (2-chloroethoxy)-.

    Code of Federal Regulations, 2010 CFR

    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...

  7. 40 CFR 721.1350 - Benzene, (1-methylethyl)(2-phenylethyl)-.

    Code of Federal Regulations, 2010 CFR

    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 721.1350 - Benzene, (1-methylethyl)(2-phenylethyl)-.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 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,...

  9. 40 CFR 721.10028 - Disubstituted benzene metal salts (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Disubstituted benzene metal salts... Specific Chemical Substances § 721.10028 Disubstituted benzene metal salts (generic). (a) Chemical... as disubstituted benzene metal salts (PMNs P-01-901 and P-01-902) are subject to reporting under...

  10. 40 CFR 721.1350 - Benzene, (1-methylethyl)(2-phenylethyl)-.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 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,...

  11. 40 CFR 721.1187 - Bis(imidoethylene) benzene.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 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...

  12. 40 CFR 721.1210 - Benzene, (2-chloroethoxy)-.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 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...

  13. 40 CFR 721.1187 - Bis(imidoethylene) benzene.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 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...

  14. 40 CFR 721.10028 - Disubstituted benzene metal salts (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Disubstituted benzene metal salts... Specific Chemical Substances § 721.10028 Disubstituted benzene metal salts (generic). (a) Chemical... as disubstituted benzene metal salts (PMNs P-01-901 and P-01-902) are subject to reporting under...

  15. 40 CFR 721.1210 - Benzene, (2-chloroethoxy)-.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 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...

  16. 40 CFR 721.1210 - Benzene, (2-chloroethoxy)-.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 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...

  17. 40 CFR 721.1187 - Bis(imidoethylene) benzene.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 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...

  18. Mutagenicity of airborne particles.

    PubMed

    Chrisp, C E; Fisher, G L

    1980-09-01

    The physical and chemical properties of airborne particles are important for the interpretation of their potential biologic significance as genotoxic hazards. For polydisperse particle size distributions, the smallest, most respirable particles are generally the most mutagenic. Particulate collection for testing purposes should be designed to reduce artifact formation and allow condensation of mutagenic compounds. Other critical factors such as UV irradiation, wind direction, chemical reactivity, humidity, sample storage, and temperature of combustion are important. Application of chemical extraction methods and subsequent class fractionation techniques influence the observed mutagenic activity. Particles from urban air, coal fly ash, automobile and diesel exhaust, agricultural burning and welding fumes contain primarily direct-acting mutagens. Cigarette smoke condensate, smoke from charred meat and protein pyrolysates, kerosene soot and cigarette smoke condensates contain primarily mutagens which require metabolic activation. Fractionation coupled with mutagenicity testing indicates that the most potent mutagens are found in the acidic fractions of urban air, coal fly ash, and automobile diesel exhaust, whereas mutagens in rice straw smoke and cigarette smoke condensate are found primarily in the basic fractions. The interaction of the many chemical compounds in complex mixtures from airborne particles is likely to be important in determining mutagenic or comutagenic potentials. Because the mode of exposure is generally frequent and prolonged, the presence of tumor-promoting agents in complex mixtures may be a major factor in evaluation of the carcinogenic potential of airborne particles.

  19. Mammalian airborne allergens.

    PubMed

    Aalberse, Rob C

    2014-01-01

    Historically, horse dandruff was a favorite allergen source material. Today, however, allergic symptoms due to airborne mammalian allergens are mostly a result of indoor exposure, be it at home, at work or even at school. The relevance of mammalian allergens in relation to the allergenic activity of house dust extract is briefly discussed in the historical context of two other proposed sources of house dust allergenic activity: mites and Maillard-type lysine-sugar conjugates. Mammalian proteins involved in allergic reactions to airborne dust are largely found in only 2 protein families: lipocalins and secretoglobins (Fel d 1-like proteins), with a relatively minor contribution of serum albumins, cystatins and latherins. Both the lipocalin and the secretoglobin family are very complex. In some instances this results in a blurred separation between important and less important allergenic family members. The past 50 years have provided us with much detailed information on the genomic organization and protein structure of many of these allergens. However, the complex family relations, combined with the wide range of post-translational enzymatic and non-enzymatic modifications, make a proper qualitative and quantitative description of the important mammalian indoor airborne allergens still a significant proteomic challenge. PMID:24925404

  20. Structure of the Sevoflurane-Benzene Complex as Determined by Chirped-Pulse Ftmw Spectroscopy

    NASA Astrophysics Data System (ADS)

    Seifert, Nathan A.; Zaleski, Daniel P.; Neill, Justin L.; Pate, Brooks H.; Lesarri, Alberto; Vallejo, Montserrat; Cocinero, Emilio J.; Castano, Fernando

    2012-06-01

    Following previous microwave studies on sevoflurane monomer by Suenram {et al.} and Vega-Toribio et al. we report the broadband rotational spectrum of sevoflurane clustered with benzene. The structure assigned is consistent with a C-H...π interaction between the benzene ring and the (CF_3)_2C-H hydrogen on sevoflurane. The spectrum of this species is complicated by the six-fold internal rotation of the benzene ring over the C_1 framework of sevoflurane. The six-fold tunneling falls into a high effective barrier case where there are several bound torsional levels. The tunneling spectrum has been successfully analyzed using the BELGI internal rotation program and a barrier to internal rotation of the benzene against sevoflurane of 32.5 cm-1 has been determined. Structural information about the complex has been obtained by studying the complex of sevoflurane with benzene-{d_1}. For this complex, six unique isomers are observed making it possible to determine the positions of the benzene H-atoms in the complex. Combination of these hydrogen r_s positions with the sevoflurane monomer r_s coordinates reported by Lesarri {et al.} results in a substitution structure in excellent agreement with the ab initio results. Finally, initial microwave results on two sevoflurane dimer species will also be presented. R. D. Suenram, D. J. Brugh, F. J. Lovas and C. Chu, 51st OSU Int. Symp. On Mol. Spectrosc., Columbus, OH, 1999, RB07. A. Vega-Toribio, A. Lesarri, R.D. Suenram, J. Grabow, 64th OSU Int. Symp. On Mol. Spectrosc., Columbus, OH, 2009, MH07. A. Lesarri, A. Vega-Toribio, R. D. Suenram, D. J. Brugh, J.-U. Grabow, Phys. Chem. Chem. Phys., 12, 9624-9631 (2010).

  1. Promoting Smoke-Free Homes: A Novel Behavioral Intervention Using Real-Time Audio-Visual Feedback on Airborne Particle Levels

    PubMed Central

    Klepeis, Neil E.; Hughes, Suzanne C.; Edwards, Rufus D.; Allen, Tracy; Johnson, Michael; Chowdhury, Zohir; Smith, Kirk R.; Boman-Davis, Marie; Bellettiere, John; Hovell, Melbourne F.

    2013-01-01

    Interventions are needed to protect the health of children who live with smokers. We pilot-tested a real-time intervention for promoting behavior change in homes that reduces second hand tobacco smoke (SHS) levels. The intervention uses a monitor and feedback system to provide immediate auditory and visual signals triggered at defined thresholds of fine particle concentration. Dynamic graphs of real-time particle levels are also shown on a computer screen. We experimentally evaluated the system, field-tested it in homes with smokers, and conducted focus groups to obtain general opinions. Laboratory tests of the monitor demonstrated SHS sensitivity, stability, precision equivalent to at least 1 µg/m3, and low noise. A linear relationship (R2 = 0.98) was observed between the monitor and average SHS mass concentrations up to 150 µg/m3. Focus groups and interviews with intervention participants showed in-home use to be acceptable and feasible. The intervention was evaluated in 3 homes with combined baseline and intervention periods lasting 9 to 15 full days. Two families modified their behavior by opening windows or doors, smoking outdoors, or smoking less. We observed evidence of lower SHS levels in these homes. The remaining household voiced reluctance to changing their smoking activity and did not exhibit lower SHS levels in main smoking areas or clear behavior change; however, family members expressed receptivity to smoking outdoors. This study established the feasibility of the real-time intervention, laying the groundwork for controlled trials with larger sample sizes. Visual and auditory cues may prompt family members to take immediate action to reduce SHS levels. Dynamic graphs of SHS levels may help families make decisions about specific mitigation approaches. PMID:24009742

  2. Airborne wireless communication systems, airborne communication methods, and communication methods

    DOEpatents

    Deaton, Juan D.; Schmitt, Michael J.; Jones, Warren F.

    2011-12-13

    An airborne wireless communication system includes circuitry configured to access information describing a configuration of a terrestrial wireless communication base station that has become disabled. The terrestrial base station is configured to implement wireless communication between wireless devices located within a geographical area and a network when the terrestrial base station is not disabled. The circuitry is further configured, based on the information, to configure the airborne station to have the configuration of the terrestrial base station. An airborne communication method includes answering a 911 call from a terrestrial cellular wireless phone using an airborne wireless communication system.

  3. The hematopoietic stem cell compartments in mice during and after long-term inhalation of three doses of benzene.

    PubMed

    Seidel, H J; Barthel, E; Zinser, D

    1989-03-01

    Female BDF1 mice were exposed for 16 weeks to airborne concentrations of 100, 300, and 900 ppm of benzene, 6 h per day, 5 days per week. Bone marrow hemopoietic stem cell compartments and peripheral blood cell counts were studied using clonal assays and standard methods. Dose-dependent depressive effects were observed on all stem cell compartments. Only the erythroid colony-forming units (CFU-E) compartment was depressed during exposures to 100 ppm; CFU-E were more sensitive than the erythroid burst-forming units (BFU-E), spleen CFU (CFU-S), or G-M CFU (CFU-C) during exposure to 300 ppm or 900 ppm. Lymphocytopenia was observed in the peripheral blood. After benzene-free intervals, a regeneration of lymphocyte numbers and slow normalization of stem cell numbers was seen. Complete recovery from the 16 weeks exposure to 300 ppm was seen between 73 and 185 days.

  4. Airborne Submillimeter Spectroscopy

    NASA Technical Reports Server (NTRS)

    Zmuidzinas, J.

    1998-01-01

    This is the final technical report for NASA-Ames grant NAG2-1068 to Caltech, entitled "Airborne Submillimeter Spectroscopy", which extended over the period May 1, 1996 through January 31, 1998. The grant was funded by the NASA airborne astronomy program, during a period of time after the Kuiper Airborne Observatory was no longer operational. Instead. this funding program was intended to help develop instrument concepts and technology for the upcoming SOFIA (Stratospheric Observatory for Infrared Astronomy) project. SOFIA, which is funded by NASA and is now being carried out by a consortium lead by USRA (Universities Space Research Association), will be a 747 aircraft carrying a 2.5 meter diameter telescope. The purpose of our grant was to fund the ongoing development of sensitive heterodyne receivers for the submillimeter band (500-1200 GHz), using sensitive superconducting (SIS) detectors. In 1997 July we submitted a proposal to USRA to construct a heterodyne instrument for SOFIA. Our proposal was successful [1], and we are now continuing our airborne astronomy effort with funding from USRA. A secondary purpose of the NAG2-1068 grant was to continue the anaIN'sis of astronomical data collected with an earlier instrument which was flown on the NASA Kuiper Airborne Observatory (KAO). The KAO instrument and the astronomical studies which were carried out with it were supported primarily under another grant, NAG2-744, which extended over October 1, 1991 through Januarv 31, 1997. For a complete description of the astronomical data and its anailysis, we refer the reader to the final technical report for NAG2-744, which was submitted to NASA on December 1. 1997. Here we report on the SIS detector development effort for SOFIA carried out under NAG2-1068. The main result of this effort has been the demonstration of SIS mixers using a new superconducting material niobium titanium nitride (NbTiN), which promises to deliver dramatic improvements in sensitivity in the 700

  5. Global deposition of airborne dioxin.

    PubMed

    Booth, Shawn; Hui, Joe; Alojado, Zoraida; Lam, Vicky; Cheung, William; Zeller, Dirk; Steyn, Douw; Pauly, Daniel

    2013-10-15

    We present a global dioxin model that simulates one year of atmospheric emissions, transport processes, and depositions to the earth's terrestrial and marine habitats. We map starting emission levels for each land area, and we also map the resulting deposits to terrestrial and marine environments. This model confirms that 'hot spots' of deposition are likely to be in northern Europe, eastern North America, and in parts of Asia with the highest marine dioxin depositions being the northeast and northwest Atlantic, western Pacific, northern Indian Ocean and the Mediterranean. It also reveals that approximately 40% of airborne dioxin emissions are deposited to marine environments and that many countries in Africa receive more dioxin than they produce, which results in these countries being disproportionately impacted. Since human exposure to dioxin is largely through diet, this work highlights food producing areas that receive higher atmospheric deposits of dioxin than others.

  6. [Combined effects of benzene and chromium on navigation learning and long-term spatial memory in rats].

    PubMed

    Tikhonov, V V; Ermolina, E V; Miroshnichenko, I V

    2009-01-01

    The impact of long-term intake of drinking water containing the high level of chromium and benzene or their mixture on navigation learning and long-term spatial memory was studied in a Morris water maze. The chronic neurotoxic effect of benzene was characterized by worse long-term memory, which upon its exposure in combination with chromium remained unchanged and failed to block the realization of a positive effect of chromium on the mechanism of navigation learning.

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

    SciTech Connect

    Trainer, Melissa G.; Sebree, Joshua A.; Heidi Yoon, Y.; Tolbert, Margaret A.

    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.

  8. Benzene, benzo(a)pyrene, and lead in smoke from tobacco products other than cigarettes.

    PubMed Central

    Appel, B R; Guirguis, G; Kim, I S; Garbin, O; Fracchia, M; Flessel, C P; Kizer, K W; Book, S A; Warriner, T E

    1990-01-01

    Benzene, benzo(a)pyrene (BaP), and lead in mainstream smoke from cigars, roll-your-own (RYO) cigarette and pipe tobaccos were sampled to evaluate their potential health significance. Results with reference cigarettes were consistent with published values, providing support for the methodology employed. The emissions of benzene and BaP, expressed as mass emitted per gram of tobacco consumed, were similar for all products evaluated; for benzene, the mean values for cigars, RYO cigarette and pipe tobaccos were 156 +/- 52, 68 +/- 11, and 242 +/- 126 micrograms/g, respectively. Mean values for BaP were 42 +/- 7 and 48 +/- 4 ng/g for cigars and RYO cigarette tobacco, respectively. Lead values were below the limit of reliable quantitation in all cases. The mean benzene concentrations in a puff ranged from 1 to 2 x 10(5) micrograms/m3 for cigars, RYO cigarette and pipe tobaccos. For BaP, the puff concentration averaged about 60 micrograms/m3 for cigars and RYO cigarette tobacco. The results suggest that smoking cigars, pipes or RYO cigarettes leads to potential exposures which exceed the No Significant Risk levels of benzene and BaP set pursuant to California's Proposition 65. These tobacco products are now required to bear a health hazard warning when sold in California. We recommend that this be adopted as national policy. PMID:2327532

  9. Effects of ethanol on benzene degradation under denitrifying conditions.

    PubMed

    Wu, Yaoguo; Li, Yunfeng; Hui, Lin; Tan, Ying; Jin, Song

    2009-02-01

    As a popular fuel oxygenate, ethanol frequently co-occurs with petroleum hydrocarbons, including benzene, in groundwater that is contaminated by gasoline. Anaerobic pathways have been identified in benzene biodegradation. Limited reports focus on denitrifying degradation of benzene; however, the role of ethanol in this pathway is unknown. This study investigated the effects of ethanol on benzene degradation under denitrifying condition by using groundwater and sediment samples collected from locations with known history of benzene contamination. Results indicate that benzene can be biodegraded under denitrifying conditions. When concentrations of nitrate were in the range of 480-920 mg/L, there is a critical value in ethanol concentration:Ethanol at concentration less than the critical value enhanced the denitrifying degradation of benzene over a period of time; in contrast, ethanol at concentration higher than the critical value, which was degraded before benzene, demonstrated an inhibitory effect. And the critical value varied with nitrate concentration. It appears that the role of ethanol may be closely associated with its own and nitrate concentrations. Two mathematical equations were established based on the data and may be used to determine if ethanol presents an enhancing or inhibitory effect on denitrification of benzene. The roles of ethanol in COD/NO(3) (-)-N and the subsequent denitrification of benzene were also studied. An optimal COD/NO(3) (-)-N ratio of 1.32 was obtained for this testing system, in which the highest rate of benzene degradation can be achieved under denitrifying conditions.

  10. Correlation between environmental and biological monitoring of exposure to benzene in petrochemical industry operators.

    PubMed

    Carrieri, Mariella; Tranfo, Giovanna; Pigini, Daniela; Paci, Enrico; Salamon, Fabiola; Scapellato, Maria L; Fracasso, Maria E; Manno, Maurizio; Bartolucci, Giovanni B

    2010-01-15

    The present work was aimed to study in petrochemical industry operators the correlation, if any, between environmental exposure to low levels of benzene and two biological exposure indexes in end-shift urine, i.e. trans, trans-muconic acid (t,t-MA) and S-phenylmercapturic acid (SPMA). Exposure to benzene was assessed in 133 male subjects employed in outdoor operations in a petrochemical plant, using personal passive-diffusive air samplers worn at the breathing zone; adsorbed benzene was determined by GC-FID analysis. S-PMA was determined by a new HPLCMS/MS method, after (quantitative) acidic hydrolysis of the cysteine conjugate precursor. t,t-MA was measured by an HPLC-UV method. Smoking habits were assessed by means of a self-administered questionnaire. Both environmental and biological monitoring data showed that benzene exposure of petrochemical industry operators was low (mean values were 0.014ppm, 101mug/g creat, and 2.8mug/g creat, for benzene, t,t-MA, and S-PMA, respectively) if compared with the ACGIH limits. Cigarette smoking was confirmed to be a strong confounding factor for the urinary excretion of both metabolites: statistically significant increases of t,t-MA and S-PMA levels were recorded in smokers when compared to non-smokers (p<0.0001). The best correlation found was that between exposure to benzene and S-PMA levels, particularly in non-smokers. This was partly due to the hydrolysis of the S-PMA precursor N-acetyl-S-(1,2-dihydro-2-hydroxyphenyl)-l-cysteine, a crucial step of the new analytical method used, which indeed reduced the variability of the results by means of an improved standardization of this critical preanalytical factor. A weaker correlation was found between exposure to benzene and t,t-MA, possibly explained by the fact that the latter is also a metabolite of sorbic acid, a common diet component. In summary, even at such low levels of exposure, urinary metabolites proved to be a useful tool for assessing individual occupational

  11. PHARUS airborne SAR concept

    NASA Astrophysics Data System (ADS)

    Snoeij, Paul; Pouwels, Henk; Koomen, Peter J.; Hoogeboom, Peter

    1995-11-01

    PHARUS (phased array universal SAR) is an airborne SAR concept which is being developed in the Netherlands. The PHARUS system differs from other airborne SARs by the use of a phased array antenna, which provides both for the flexibility in the design as well as for a compact, light-weight instrument that can be carried on small aircraft. The concept allows for the construction of airborne SAR systems on a common generic basis but tailored to specific user needs and can be seen as a preparation for future spaceborne SAR systems using solid state transmitters with electronically steerable phased array antenna. The whole approach is aimed at providing an economic and yet technically sophisticated solution to remote sensing or surveying needs of a specific user. The solid state phased array antenna consists of a collection of radiating patches; the design flexibility for a large part resides in the freedom to choose the number of patches, and thereby the essential radar performance parameters such as resolution and swath width. Another consequence of the use of the phased array antenna is the system's compactness and the possibility to rigidly mount it on a small aircraft. The use of small aircraft of course considerably improves the cost/benefit ratio of the use of airborne SAR. Flight altitude of the system is flexible between about 7,000 and 40,000 feet, giving much operational freedom within the meteo and airspace control limits. In the PHARUS concept the airborne segment is complemented by a ground segment, which consists of a SAR processor, possibly extended by a matching image processing package. (A quick look image is available in real-time on board the aircraft.) The SAR processor is UNIX based and runs on easily available hardware (SUN station). Although the additional image processing software is available, the SAR processing software is nevertheless designed to be able to interface with commercially available image processing software, as well as being able

  12. Mapping methane emission sources over California based on airborne measurements

    NASA Astrophysics Data System (ADS)

    Karl, T.; Guha, A.; Peischl, J.; Misztal, P. K.; Jonsson, H.; Goldstein, A. H.; Ryerson, T. B.

    2011-12-01

    The California Global Warming Solutions Act of 2006 (AB 32) has created a need to accurately characterize the emission sources of various greenhouse gases (GHGs) and verify the existing state GHG inventory. Methane (CH4) is a major GHG with a global warming potential of 20 times that of CO2 and currently constitutes about 6% of the total statewide GHG emissions on a CO2 equivalent basis. Some of the major methane sources in the state are area sources where methane is biologically produced (e.g. dairies, landfills and waste treatment plants) making bottom-up estimation of emissions a complex process. Other potential sources include fugitive emissions from oil extraction processes and natural gas distribution network, emissions from which are not well-quantified. The lack of adequate field measurement data to verify the inventory and provide independently generated estimates further contributes to the overall uncertainty in the CH4 inventory. In order to gain a better perspective of spatial distribution of major CH4 sources in California, a real-time measurement instrument based on Cavity Ring Down Spectroscopy (CRDS) was installed in a Twin Otter aircraft for the CABERNET (California Airborne BVOC Emissions Research in Natural Ecosystems Transects) campaign, where the driving research goal was to understand the spatial distribution of biogenic VOC emissions. The campaign took place in June 2011 and encompassed over forty hours of airborne CH4 and CO2 measurements during eight unique flights which covered much of the Central Valley and its eastern edge, the Sacramento-San Joaquin delta and the coastal range. The coincident VOC measurements, obtained through a high frequency proton transfer reaction mass spectrometer (PTRMS), aid in CH4 source identification. High mixing ratios of CH4 (> 2000 ppb) are observed consistently in all the flight transects above the Central Valley. These high levels of CH4 are accompanied by high levels of methanol which is an important

  13. Occupational exposure to benzene at the ExxonMobil refinery at Baton Rouge, Louisiana (1977-2005).

    PubMed

    Panko, Julie M; Gaffney, Shannon H; Burns, Amanda M; Unice, Ken M; Kreider, Marisa L; Booher, Lindsay E; Gelatt, Richard H; Marshall, J Ralph; Paustenbach, Dennis J

    2009-09-01

    Because crude oil contains up to 3% benzene and there is an association between high chronic exposure to appreciable concentrations of benzene and acute myelogenous leukemia, exposure of refinery workers has been studied for many years. To date, no extensive industrial hygiene exposure analyses for historical benzene exposure have been performed, and none have focused on the airborne concentrations in the workplace at specific refineries or for specific tasks. In this study, the authors evaluated the airborne concentrations of benzene and their variability over time at the ExxonMobil refinery in Baton Rouge between 1977 and 2005. Refinery workers were categorized into 117 worker groups using company job descriptions. These 117 groups were further collapsed into 25 job categories based on similarity of measured exposure results. Results of 5289 personal air samples are included in this analysis; 3403 were considered nontask (>or= 180 min) personal samples, and 830 were considered task-related (< 180 min) personal samples; the remainder did not fit in either category. In general, nontask personal air samples indicated that exposures of the past 30 years were generally below the occupational exposure limit of 1 ppm, but there was only a small, decreasing temporal trend in the concentrations. The job sampled most frequently during routine operations was process technician and, as broken down by area, resulted in the following mean benzene concentrations: analyzers (mean = 0.12 ppm), coker (mean = 0.013 ppm), hydrofiner (mean = 0.0054 ppm), lube blending and storage (mean = 0.010 ppm), waste treatment (mean = 0.092 ppm), and all other areas (mean = 0.055 ppm). Task-based samples indicated that the highest exposures resulted from the sampling tasks, specifically from those performed on process materials; in general, though, even these tasks had concentrations well below the STEL of 5 ppm. The most frequently sampled task was gauging (mean = 0.12 ppm). Task

  14. Airborne Oceanographic Lidar System

    NASA Technical Reports Server (NTRS)

    Bressel, C.; Itzkan, I.; Nunes, J. E.; Hoge, F.

    1977-01-01

    The Airborne Oceanographic Lidar (AOL), a spatially scanning range-gated device installed on board a NASA C-54 aircraft, is described. The AOL system is capable of measuring topographical relief or water depth (bathymetry) with a range resolution of plus or minus 0.3 m in the vertical dimension. The system may also be used to measure fluorescent spectral signatures from 3500 to 8000 A with a resolution of 100 A. Potential applications of the AOL, including sea state measurements, water transparency assessments, oil spill identification, effluent identification and crop cover assessment are also mentioned.

  15. Airborne electronics for automated flight systems

    NASA Technical Reports Server (NTRS)

    Graves, G. B., Jr.

    1975-01-01

    The increasing importance of airborne electronics for use in automated flight systems is briefly reviewed with attention to both basic aircraft control functions and flight management systems for operational use. The requirements for high levels of systems reliability are recognized. Design techniques are discussed and the areas of control systems, computing and communications are considered in terms of key technical problems and trends for their solution.

  16. Health Risk Assessment for Exposure to Benzene in Petroleum Refinery Environments

    PubMed Central

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

    2015-01-01

    The health risk resulting from benzene exposure in petroleum refineries was calculated using data from the scientific literature from various countries throughout the world. The exposure data was collated into four scenarios from petroleum refinery environments and plotted as cumulative probability distributions (CPD) plots. Health risk was evaluated for each scenario using the Hazard Quotient (HQ) at 50% (CEXP50) and 95% (CEXP95) exposure levels. Benzene levels were estimated to pose a significant risk with HQ50 > 1 and HQ95 > 1 for workers exposed to benzene as base estimates for petroleum refinery workers (Scenario 1), petroleum refinery workers evaluated with personal samplers in Bulgarian refineries (Scenario 2B) and evaluated using air inside petroleum refineries in Bulgarian refineries (Scenario 3B). HQ50 < 1 were calculated for petroleum refinery workers with personal samplers in Italian refineries (Scenario 2A), air inside petroleum refineries (Scenario 3A) and air outside petroleum refineries (Scenario 4) in India and Taiwan indicating little possible adverse health effects. Also, HQ95 was < 1 for Scenario 4 however potential risk was evaluated for Scenarios 2A and 3A with HQ95 > 1. The excess Cancer risk (CR) for lifetime exposure to benzene for all the scenarios was evaluated using the Slope Factor and Overall Risk Probability (ORP) methods. The result suggests a potential cancer risk for exposure to benzene in all the scenarios. However, there is a higher cancer risk at 95% (CEXP95) for petroleum refinery workers (2B) with a CR of 48,000 per 106 and exposure to benzene in air inside petroleum refineries (3B) with a CR of 28,000 per 106. PMID:25588154

  17. Health risk assessment for exposure to benzene in petroleum refinery environments.

    PubMed

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

    2015-01-12

    The health risk resulting from benzene exposure in petroleum refineries was calculated using data from the scientific literature from various countries throughout the world. The exposure data was collated into four scenarios from petroleum refinery environments and plotted as cumulative probability distributions (CPD) plots. Health risk was evaluated for each scenario using the Hazard Quotient (HQ) at 50% (CEXP50) and 95% (CEXP95) exposure levels. Benzene levels were estimated to pose a significant risk with HQ50 > 1 and HQ95 > 1 for workers exposed to benzene as base estimates for petroleum refinery workers (Scenario 1), petroleum refinery workers evaluated with personal samplers in Bulgarian refineries (Scenario 2B) and evaluated using air inside petroleum refineries in Bulgarian refineries (Scenario 3B). HQ50 < 1 were calculated for petroleum refinery workers with personal samplers in Italian refineries (Scenario 2A), air inside petroleum refineries (Scenario 3A) and air outside petroleum refineries (Scenario 4) in India and Taiwan indicating little possible adverse health effects. Also, HQ95 was < 1 for Scenario 4 however potential risk was evaluated for Scenarios 2A and 3A with HQ95 > 1. The excess Cancer risk (CR) for lifetime exposure to benzene for all the scenarios was evaluated using the Slope Factor and Overall Risk Probability (ORP) methods. The result suggests a potential cancer risk for exposure to benzene in all the scenarios. However, there is a higher cancer risk at 95% (CEXP95) for petroleum refinery workers (2B) with a CR of 48,000 per 106 and exposure to benzene in air inside petroleum refineries (3B) with a CR of 28,000 per 106.

  18. An analysis of workplace exposures to benzene over four decades at a petrochemical processing and manufacturing facility (1962-1999).

    PubMed

    Sahmel, J; Devlin, K; Burns, A; Ferracini, T; Ground, M; Paustenbach, D

    2013-01-01

    Benzene, a known carcinogen, can be generated as a by-product during the use of petroleum-based raw materials in chemical manufacturing. The aim of this study was to analyze a large data set of benzene air concentration measurements collected over nearly 40 years during routine employee exposure monitoring at a petrochemical manufacturing facility. The facility used ethane, propane, and natural gas as raw materials in the production of common commercial materials such as polyethylene, polypropylene, waxes, adhesives, alcohols, and aldehydes. In total, 3607 benzene air samples were collected at the facility from 1962 to 1999. Of these, in total 2359 long-term (>1 h) personal exposure samples for benzene were collected during routine operations at the facility between 1974 and 1999. These samples were analyzed by division, department, and job title to establish employee benzene exposures in different areas of the facility over time. Sampling data were also analyzed by key events over time, including changes in the occupational exposure limits (OELs) for benzene and key equipment process changes at the facility. Although mean benzene concentrations varied according to operation, in nearly all cases measured benzene quantities were below the OEL in place at the time for benzene (10 ppm for 1974-1986 and 1 ppm for 1987-1999). Decreases in mean benzene air concentrations were also found when data were evaluated according to 7- to 10-yr periods following key equipment process changes. Further, an evaluation of mortality rates for a retrospective employee cohort (n = 3938) demonstrated that the average personal benzene exposures at this facility (0.89 ppm for the period 1974-1986 and 0.125 ppm for the period 1987-1999) did not result in increased standardized mortality ratio (SMRs) for diseases or malignancies of the lymphatic system. The robust nature of this data set provides comprehensive exposure information that may be useful for assessing human benzene exposures at

  19. Risk analysis for worker exposure to benzene

    NASA Astrophysics Data System (ADS)

    Hallenbeck, William H.; Flowers, Roxanne E.

    1992-05-01

    Cancer risk factors (characterized by route, dose, dose rate per kilogram, fraction of lifetime exposed, species, and sex) were derived for workers exposed to benzene via inhalation or ingestion. Exposure at the current Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL) and at leaking underground storage tank (LUST) sites were evaluated. At the current PEL of 1 ppm, the theoretical lifetime excess risk of cancer from benzene inhalation is ten per 1000. The theoretical lifetime excess risk for worker inhalation exposure at LUST sites ranged from 10 to 40 per 1000. These results indicate that personal protection should be required. The theoretical lifetime excess risk due to soil ingestion is five to seven orders of magnitude less than the inhalation risks.

  20. Benzene inhalation produces leukemia in mice.

    PubMed

    Cronkite, E P; Bullis, J; Inoue, T; Drew, R T

    1984-09-15

    Female C57Bl/6 mice were exposed to 300 ppm benzene 6 hr/day, 5 days/week for 16 weeks and then held for lifetime observation. Sixty-four weeks after commencement of the study, 10 of 90 exposed mice had died as opposed to only 1 of 88 controls. Of the 10 exposed mice that died, 6 had thymic lymphomas, 2 had unspecified lymphomas, 1 was killed when moribund and found leukemia-free, and 1 was undiagnosed due to autolysis and partial cannibalization. The single dead control animal did not have lymphoma or leukemia. These data provide proof of the leukemogenicity of benzene in female C57Bl/6 mice.

  1. Structural basis of enzymatic benzene ring reduction.

    PubMed

    Weinert, Tobias; Huwiler, Simona G; Kung, Johannes W; Weidenweber, Sina; Hellwig, Petra; Stärk, Hans-Joachim; Biskup, Till; Weber, Stefan; Cotelesage, Julien J H; George, Graham N; Ermler, Ulrich; Boll, Matthias

    2015-08-01

    In chemical synthesis, the widely used Birch reduction of aromatic compounds to cyclic dienes requires alkali metals in ammonia as extremely low-potential electron donors. An analogous reaction is catalyzed by benzoyl-coenzyme A reductases (BCRs) that have a key role in the globally important bacterial degradation of aromatic compounds at anoxic sites. Because of the lack of structural information, the catalytic mechanism of enzymatic benzene ring reduction remained obscure. Here, we present the structural characterization of a dearomatizing BCR containing an unprecedented tungsten cofactor that transfers electrons to the benzene ring in an aprotic cavity. Substrate binding induces proton transfer from the bulk solvent to the active site by expelling a Zn(2+) that is crucial for active site encapsulation. Our results shed light on the structural basis of an electron transfer process at the negative redox potential limit in biology. They open the door for biological or biomimetic alternatives to a basic chemical synthetic tool.

  2. Metatranscriptome of an anaerobic benzene-degrading, nitrate-reducing enrichment culture reveals involvement of carboxylation in benzene ring activation.

    PubMed

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

    2014-07-01

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

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

    PubMed Central

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

    2014-01-01

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

  4. Identifying areas with potential for high indoor radon levels: analysis of the national airborne radiometric reconnaissance data for California and the Pacific Northwest

    SciTech Connect

    Moed, B.A.; Nazaroff, W.W.; Nero, A.V.; Schwehr, M.B.; Van Heuvelen, A.

    1984-04-01

    Radon-222 is an important indoor air pollutant which, through the inhalation of its radioactive decay products, accounts for nearly half of the effective dose equivalent to the public from natural ionizing radiation. Indoor radon concentrations vary widely, largely because of local and regional differences in the rate of entry from sources. The major sources are soil and rock near building foundations, earth-based building materials, and domestic water; of these, soil and rock are thought to be predominant in many buildings with higher-than-average concentrations. Thus, one key factor in determining radon source potential is the concentration of radium, the progenitor of radon, in surficial rocks and soils. Aerial radiometric data were analyzed, collected for the National Uranium Resource Evaluation Program, for seven Western states to: (1) provide information on the spatial distribution of radium contents in surficial geologic materials for those states; and (2) investigate approaches for using the aerial data, which have been collected throughout the contiguous United States and Alaska, to identify areas where high indoor radon levels may be common. Radium concentrations were found to be relatively low in central and western portions of Washington, Oregon, and northern California; they were found to be relatively high in central and southern California. A field validation study, conducted along two flight-line segments near Spokane, Washington, showed close correspondence between the aerial data, in situ measurements of both radium content and radon flux from soil, and laboratory measurements of both radium content of and radon emanation rate from soil samples. 99 references, 11 figures, 3 tables.

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

    SciTech Connect

    Dougal, R.A.

    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.

  6. Modeling Airborne Gravimetry with High-Degree Harmonic Expansions

    NASA Astrophysics Data System (ADS)

    Holmes, Simon; Wang, Yan Ming; Roman, Daniel

    2010-05-01

    Since its official unveiling at the 2008 General Assembly of the European Geosciences Union, EGM2008 has demonstrated that high-degree harmonic expansions constitute a useful and effective final representation for high-resolution global gravitational models. However, such expansions also provide a versatile means of capturing (modeling), inter-comparing, and optimally combining local and regional high-resolution terrestrial data sets of different types. Here we present a general recipe for using high-degree expansions to capture, downward-continue and assimilate airborne survey data. This approach relies on the production of two ‘competing' high-degree expansions. A first, ‘terrestrial-only' expansion incorporates EGM2008 globally, and high-resolution terrestrial gravimetry regionally. This expansion can be used to upward-continue the regional terrestrial data to the flight level of the airborne survey, such that the terrestrial gravimetry outside the survey area can be merged with the airborne data inside the survey area, all at flight level. Harmonic analysis of this merged data set, also at flight level, yields a second ‘airborne-augmented' expansion, which closely matches the ‘terrestrial-only' expansion outside the survey area, but which also closely reproduces the airborne survey data inside the survey area. Capturing the airborne and terrestrial data in this way means that downward-continuation of the airborne data, as well as spectral/spatial comparison (and ultimate combination) of the airborne data with the terrestrial (and satellite) data, can all be achieved through spherical- and ellipsoidal-harmonic synthesis of these two competing expansions, and their spectral combination. This general approach is illustrated with a worked example.

  7. The Self-Assembly Properties of a Benzene-1,3,5-tricarboxamide Derivative

    ERIC Educational Resources Information Center

    Stals, Patrick J. M.; Haveman, Jan F.; Palmans, Anja R. A.; Schenning, Albertus P. H. J.

    2009-01-01

    A series of experiments involving the synthesis and characterization of a benzene-1,3,5-tricarboxamide derivative and its self-assembly properties are reported. These laboratory experiments combine organic synthesis, self-assembly, and physical characterization and are designed for upper-level undergraduate students to introduce the topic of…

  8. Airborne concentrations of peanut protein.

    PubMed

    Johnson, Rodney M; Barnes, Charles S

    2013-01-01

    Food allergy to peanut is a significant health problem, and there are reported allergic reactions to peanuts despite not eating or having physical contact with peanuts. It is presumed that an allergic reaction may have occurred from inhalation of airborne peanut allergens. The purpose of this study was to detect the possible concentrations of airborne peanut proteins for various preparations and during specific activities. Separate Ara h 1 and Ara h 2 monoclonal enzyme-linked immunosorbent assays and a polyclonal sandwich enzyme immunoassay for peanuts were used to detect the amount of airborne peanut protein collected using a Spincon Omni 3000 air collector (Sceptor Industries, Inc., Kansas City, MO) under different peanut preparation methods and situations. Air samples were measured for multiple peanut preparations and scenarios. Detectable amounts of airborne peanut protein were measured using a whole peanut immunoassay when removing the shells of roasted peanut. No airborne peanut allergen (Ara h 1 or Ara h 2) or whole peanut protein above the LLD was measured in any of the other peanut preparation collections. Ara h 1, Ara h 2, and polyclonal peanut proteins were detected from water used to boil peanuts. Small amounts of airborne peanut protein were detected in the scenario of removing shells from roasted peanuts; however, Ara h 1 and Ara h 2 proteins were unable to be consistently detected. Although airborne peanut proteins were detected, the concentration of airborne peanut protein that is necessary to elicit a clinical allergic reaction is unknown.

  9. Airborne ballistic camera tracking systems

    NASA Technical Reports Server (NTRS)

    Redish, W. L.

    1976-01-01

    An operational airborne ballistic camera tracking system was tested for operational and data reduction feasibility. The acquisition and data processing requirements of the system are discussed. Suggestions for future improvements are also noted. A description of the data reduction mathematics is outlined. Results from a successful reentry test mission are tabulated. The test mission indicated that airborne ballistic camera tracking systems are feasible.

  10. Airborne concentrations of peanut protein.

    PubMed

    Johnson, Rodney M; Barnes, Charles S

    2013-01-01

    Food allergy to peanut is a significant health problem, and there are reported allergic reactions to peanuts despite not eating or having physical contact with peanuts. It is presumed that an allergic reaction may have occurred from inhalation of airborne peanut allergens. The purpose of this study was to detect the possible concentrations of airborne peanut proteins for various preparations and during specific activities. Separate Ara h 1 and Ara h 2 monoclonal enzyme-linked immunosorbent assays and a polyclonal sandwich enzyme immunoassay for peanuts were used to detect the amount of airborne peanut protein collected using a Spincon Omni 3000 air collector (Sceptor Industries, Inc., Kansas City, MO) under different peanut preparation methods and situations. Air samples were measured for multiple peanut preparations and scenarios. Detectable amounts of airborne peanut protein were measured using a whole peanut immunoassay when removing the shells of roasted peanut. No airborne peanut allergen (Ara h 1 or Ara h 2) or whole peanut protein above the LLD was measured in any of the other peanut preparation collections. Ara h 1, Ara h 2, and polyclonal peanut proteins were detected from water used to boil peanuts. Small amounts of airborne peanut protein were detected in the scenario of removing shells from roasted peanuts; however, Ara h 1 and Ara h 2 proteins were unable to be consistently detected. Although airborne peanut proteins were detected, the concentration of airborne peanut protein that is necessary to elicit a clinical allergic reaction is unknown. PMID:23406937

  11. Benzene contamination at a metal plating facility

    NASA Astrophysics Data System (ADS)

    Memon, B. A.; Burston, M. R.

    2005-08-01

    A metal plating facility in central Kentucky was required to complete a RCRA Facility Investigation to address a number of Solid Waste Management Units at the site. Twenty monitoring wells were installed at the facility. Ground water from the wells was sampled for total and dissolved metals, polychlorinated biphenyls, acid extractable compounds, base neutral compounds, and volatile organic compounds. Unexpectedly, relatively large concentrations of benzene, up to 120 μg/l, were detected in samples from some of the wells, including wells that should have been hydraulically upgradient from the facility. As a result of the detection of benzene, the facility completed an investigation to identify the source. A nearby facility had completed a gasoline underground storage tank (UST) closure at about the time of the installation of the 20 wells. Reportedly the UST had small holes when removed. Three potential pathways of migration (a ditch, sanitary sewer, and a sink hole) from the nearby facility to the metal-plating facility and residual soils with very large concentrations of benzene, toluene, ethylbenzene, and xylenes have been identified.

  12. Accumulation of chlorinated benzenes in earthworms

    SciTech Connect

    Beyer, W.N.

    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.

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

    SciTech Connect

    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.

  14. Benzene-RISc: The development and performance of an immunoassay to detect benzene in water

    SciTech Connect

    Friedman, S.B.; Withers, T.; Almond, R.; Stewart, T.; Allen, R.L.

    1994-12-31

    Immunoassay methods have become available for environmental applications. Their simplicity, reliability, and ability to provide information rapidly and on-site is enhancing the efficiency of many field and laboratory programs. Immunoassay methods rely upon antibody molecules to provide the sensitivity and specificity characteristics they exhibit, but many molecules are either insufficiently immunogenic or structurally unremarkable to induce an appropriate antibody response. Such compounds are usually considered to be incompatible with the development of an immunoassay method. An immunoassay method for the detection of benzene in water would have utility in detecting contamination from spills and leaking underground storage tanks. Benzene, however, is frequently considered to be in the class of compounds considered to be incompatible with antibody, and therefore immunoassay, development. The authors have developed an immunoassay for the detection of benzene in water by developing both sample processing and immunochemical procedures and reagents that overcome the technical limitations frequently encountered.

  15. Benzene's metabolites alter c-MYB activity via reactive oxygen species in HD3 cells

    SciTech Connect

    Wan, Joanne; Winn, Louise M. . E-mail: winnl@queensu.ca

    2007-07-15

    Benzene is a known leukemogen that is metabolized to form reactive intermediates and reactive oxygen species (ROS). The c-Myb oncoprotein is a transcription factor that has a critical role in hematopoiesis. c-Myb transcript and protein have been overexpressed in a number of leukemias and cancers. Given c-Myb's role in hematopoiesis and leukemias, it is hypothesized that benzene interferes with the c-Myb signaling pathway and that this involves ROS. To investigate our hypothesis, we evaluated whether benzene, 1,4-benzoquinone, hydroquinone, phenol, and catechol generated ROS in chicken erythroblast HD3 cells, as measured by 5-(and-6)-chloromethyl-2',7'-dichlorodihydrofluorescein diacetate (DCFDA) and dihydrorhodamine-123 (DHR-123), and whether the addition of 100 U/ml of the antioxidating enzyme superoxide dismutase (SOD) could prevent ROS generation. Reduced to oxidized glutathione ratios (GSH:GSSG) were also assessed as well as hydroquinone and benzoquinone's effects on c-Myb protein levels and activation of a transiently transfected reporter construct. Finally we attempted to abrogate benzene metabolite mediated increases in c-Myb activity with the use of SOD. We found that benzoquinone, hydroquinone, and catechol increased DCFDA fluorescence, increased DHR-123 fluorescence, decreased GSH:GSSG ratios, and increased reporter construct expression after 24 h of exposure. SOD was able to prevent DCFDA fluorescence and c-Myb activity caused by benzoquinone and hydroquinone only. These results are consistent with other studies, which suggest metabolite differences in benzene-mediated toxicity. More importantly, this study supports the hypothesis that benzene may mediate its toxicity through ROS-mediated alterations in the c-Myb signaling pathway.

  16. Protective role of glycerol against benzene stress: insights from the Pseudomonas putida proteome.

    PubMed

    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

  17. Modeling for Airborne Contamination

    SciTech Connect

    F.R. Faillace; Y. Yuan

    2000-08-31

    The objective of Modeling for Airborne Contamination (referred to from now on as ''this report'') is to provide a documented methodology, along with supporting information, for estimating the release, transport, and assessment of dose to workers from airborne radioactive contaminants within the Monitored Geologic Repository (MGR) subsurface during the pre-closure period. Specifically, this report provides engineers and scientists with methodologies for estimating how concentrations of contaminants might be distributed in the air and on the drift surfaces if released from waste packages inside the repository. This report also provides dose conversion factors for inhalation, air submersion, and ground exposure pathways used to derive doses to potentially exposed subsurface workers. The scope of this report is limited to radiological contaminants (particulate, volatile and gaseous) resulting from waste package leaks (if any) and surface contamination and their transport processes. Neutron activation of air, dust in the air and the rock walls of the drift during the preclosure time is not considered within the scope of this report. Any neutrons causing such activation are not themselves considered to be ''contaminants'' released from the waste package. This report: (1) Documents mathematical models and model parameters for evaluating airborne contaminant transport within the MGR subsurface; and (2) Provides tables of dose conversion factors for inhalation, air submersion, and ground exposure pathways for important radionuclides. The dose conversion factors for air submersion and ground exposure pathways are further limited to drift diameters of 7.62 m and 5.5 m, corresponding to the main and emplacement drifts, respectively. If the final repository design significantly deviates from these drift dimensions, the results in this report may require revision. The dose conversion factors are further derived by using concrete of sufficient thickness to simulate the drift

  18. Emissions of volatile organic compounds inferred from airborne flux measurements over a megacity

    NASA Astrophysics Data System (ADS)

    Karl, T.; Apel, E.; Hodzic, A.; Riemer, D.; Blake, D.; Wiedinmyer, C.

    2008-07-01

    Toluene and benzene are used for assessing the ability to measure disjunct eddy covariance (DEC) fluxes of Volatile Organic Compounds (VOC) using Proton Transfer Reaction Mass Spectrometry (PTR-MS) on aircraft. Statistically significant correlation between vertical wind speed and mixing ratios suggests that airborne VOC eddy covariance (EC) flux measurements using PTR-MS are feasible. City-average midday toluene and benzene fluxes are calculated to be on the order of 15.5±4.0 mg/m2/h and 4.7±2.3 mg/m2/h respectively. These values argue for an underestimation of toluene and benzene emissions in current inventories used for the Mexico City Metropolitan Area (MCMA). Wavelet analysis of instantaneous toluene and benzene measurements during city overpasses is tested as a tool to assess surface emission heterogeneity. High toluene to benzene flux ratios above an industrial district (e.g. 10 15) including the International airport (e.g. 3 5) and a mean flux (concentration) ratio of 3.2±0.5 (3.9±0.3) across Mexico City indicate that evaporative fuel and industrial emissions play an important role for the prevalence of aromatic compounds. Based on a tracer model, which was constrained by BTEX (Benzene/Toluene/Ethylbenzene/m,p,o-Xylenes) compound concentration ratios, the fuel marker methyl-tertiary-butyl-ether (MTBE) and the biomass burning marker acetonitrile (CH3CN), we show that a combination of industrial, evaporative fuel, and exhaust emissions account for >90% of all BTEX sources. Our observations suggest that biomass burning emissions play a minor role for the abundance of BTEX compounds (0 10%) in the MCMA.

  19. Latest Advancement In Airborne Relative Gravity Instrumentation.

    NASA Astrophysics Data System (ADS)

    Brady, N.

    2011-12-01

    new system are: - Reduce the size of the system to approximately one third of the volume of the original TAGS and reduce the weight by one half. - Use slip ring technology to eliminate cable drag on the sensor and gimbal platform. - Use a double oven system to further isolate the gravity sensor from large external temperature variations commonly experienced in airborne survey operations. - Completely redesign both the platform control system and data acquisition and recording system to eliminate reliance on standard computer and windows software enhancing reliability and data throughput. - Increase data recording rate to 20 hertz to assist in making GPS corrections to platform levelling. - Use an advanced force feedback system to increase system resolution in turbulent conditions, eliminate dependence on the spring tension counter and the need to clamp the beam during turns. - Enable the system to be used for drape flying and remove the requirement for an operator and hence be suitable for unmanned aerial vehicle (UAV) operations. Prototype testing of the mechanical and electronic components has been ongoing through the first half of 2011. Ground testing and airborne testing began in May of 2011 and will continue through until October of 2011. This paper will present the results of the full hardware testing in different environments and confirmation of the capabilities of the system.

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

    PubMed

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

    2015-04-01

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

  1. Airborne agent concentration analysis

    DOEpatents

    Gelbard, Fred

    2004-02-03

    A method and system for inferring airborne contaminant concentrations in rooms without contaminant sensors, based on data collected by contaminant sensors in other rooms of a building, using known airflow interconnectivity data. The method solves a least squares problem that minimizes the difference between measured and predicted contaminant sensor concentrations with respect to an unknown contaminant release time. Solutions are constrained to providing non-negative initial contaminant concentrations in all rooms. The method can be used to identify a near-optimal distribution of sensors within the building, when then number of available sensors is less than the total number of rooms. This is achieved by having a system-sensor matrix that is non-singular, and by selecting that distribution which yields the lowest condition number of all the distributions considered. The method can predict one or more contaminant initial release points from the collected data.

  2. Airborne Wind Turbine

    SciTech Connect

    2010-09-01

    Broad Funding Opportunity Announcement Project: Makani Power is developing an Airborne Wind Turbine (AWT) that eliminates 90% of the mass of a conventional wind turbine and accesses a stronger, more consistent wind at altitudes of near 1,000 feet. At these altitudes, 85% of the country can offer viable wind resources compared to only 15% accessible with current technology. Additionally, the Makani Power wing can be economically deployed in deep offshore waters, opening up a resource which is 4 times greater than the entire U.S. electrical generation capacity. Makani Power has demonstrated the core technology, including autonomous launch, land, and power generation with an 8 meter wingspan, 20 kW prototype. At commercial scale, Makani Power aims to develop a 600 kW, 28 meter wingspan product capable of delivering energy at an unsubsidized cost competitive with coal, the current benchmark for low-cost power.

  3. Comparing the effects of various fuel alcohols on the natural attenuation of Benzene Plumes using a general substrate interaction model

    NASA Astrophysics Data System (ADS)

    Gomez, Diego E.; Alvarez, Pedro J. J.

    2010-04-01

    The effects of five fuel alcohols (methanol, ethanol, 1-propanol, iso-butanol and n-butanol) on the natural attenuation of benzene were compared using a previously developed numerical model (General Substrate Interaction Module — GSIM) and a probabilistic sensitivity analysis. Simulations with a 30 gal dissolving LNAPL (light non-aqueous phase liquid) source consisting of a range of gasoline blends (10% and 85% v:v alcohol content) suggest that all fuel alcohols can hinder the natural attenuation of benzene, due mainly to accelerated depletion of dissolved oxygen and a decrease in the specific degradation rate for benzene (due to catabolite repression and metabolic flux dilution). Simulations for blends with 10% alcohol, assuming a homogeneous sandy aquifer, inferred maximum benzene plume elongations (relative to a regular gasoline release) of 26% for ethanol, 47% for iso-butanol, 147% for methanol, 188% for 1-propanol, and 265% for n-butanol. The corresponding elongation percentages for blends with 85% alcohol were generally smaller (i.e., 25%, 54%, 135%, 163%, and 181%, respectively), reflecting a lower content of benzene in the simulated release. Benzene plume elongation and longevity were more pronounced in the presence of alcohols that biodegrade slower (e.g., propanol and n-butanol), forming longer and more persistent alcohol plumes. Conversely, ethanol and iso-butanol exhibited the lowest potential to hinder the natural attenuation of benzene, illustrating the significant effect that a small difference in chemical structure (e.g., isomers) can have on biodegradation. Overall, simulations were highly sensitive to site-specific biokinetic coefficients for alcohol degradation, which forewarns against generalizations about the level of impact of specific fuel alcohols on benzene plume dynamics.

  4. Airborne Cloud Computing Environment (ACCE)

    NASA Technical Reports Server (NTRS)

    Hardman, Sean; Freeborn, Dana; Crichton, Dan; Law, Emily; Kay-Im, Liz

    2011-01-01

    Airborne Cloud Computing Environment (ACCE) is JPL's internal investment to improve the return on airborne missions. Improve development performance of the data system. Improve return on the captured science data. The investment is to develop a common science data system capability for airborne instruments that encompasses the end-to-end lifecycle covering planning, provisioning of data system capabilities, and support for scientific analysis in order to improve the quality, cost effectiveness, and capabilities to enable new scientific discovery and research in earth observation.

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

    PubMed

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

    2010-09-15

    The objective of this study was to determine benzene and 1,3-butadiene exposure through ambient air and personal air monitoring, as well as through biomarkers of exposure, and to evaluate the potential health risk of exposure through the use of biomarkers of early biological effects in central Bangkok traffic policemen. Ambient air concentrations of benzene and 1,3-butadiene at the roadsides were significantly higher than in police offices used as control sites (p<0.001). Traffic policemen had a significantly higher exposure to benzene (median 38.62 microg/m(3)) and 1,3-butadiene (median 3.08 microg/m(3)) than office policemen (median 6.17 microg/m(3) for benzene and 0.37 microg/m(3) for 1,3-butadiene) (p<0.001). Biomarkers of benzene exposure, blood benzene, and urinary metabolite, trans, trans-muconic acid were significantly higher in traffic policemen than office policemen (p<0.001). No significant difference between traffic and office policemen was found in urinary benzene metabolite, S-phenyl mercapturic acid, or in urinary 1,3-butadiene metabolite, monohydroxy-butenyl mercapturic acid. Biomarkers of early biological effects, 8-hydroxy-2'-deoxyguanosine in leukocytes (8-OHdG), DNA-strand breaks, and DNA-repair capacity, measured as an increase in gamma ray-induced chromosome aberrations were significantly higher in traffic policemen than controls (p<0.001 for 8-OHdG, p<0.01 for tail length, p<0.001 for olive tail moment, p<0.05 for dicentrics and p<0.01 for deletions). Multiple regression model including individual exposure, biomarkers of exposure, ages and years of work as independent variables showed that only the levels of individual 1,3-butadiene exposure were significantly associated with 8-OHdG and olive tail moment at p<0.0001 indicating more influence of 1,3-butadiene on DNA damage. These results indicated that traffic policemen, who are exposed to benzene and 1,3-butadiene at the roadside in central Bangkok, are potentially at a higher risk for

  6. Exposure to benzene, toluene, xylenes and total hydrocarbons among snowmobile drivers in Sweden.

    PubMed

    Eriksson, Kåre; Tjärner, Dan; Marqvardsen, Inger; Järvholm, Bengt

    2003-03-01

    The exposure to benzene, toluene, xylenes and total hydrocarbons among 25 individuals exposed to exhaust from a snowmobile equipped with a two-stroke engine has been evaluated. Sampling was performed by pumped and diffusive sampling in parallel. There was a relatively bad agreement between the two air-sampling methods. The bad agreement can in part be explained by back diffusion of the substances from the samplers, a high face velocity, and deposition of droplets of unburned gasoline onto or in the vicinity of the samplers. The levels of benzene ranged from not detectable (< or =0.01 mgm(-3)) to 2.5 mgm(-3). For toluene, xylenes and total hydrocarbons the exposure was 0.10-12.0, < or =0.05-13.0 and 0.90-273 mgm(-3) respectively. The result from two measurements on individuals travelling on an open sleigh at the rear of the vehicle indicated higher levels of benzene, 0.7-0.8 mgm(-3). Children are often riding as a passenger on a sledge and may thus have a higher exposure than their parents. This study indicates that spare time driving a snowmobile may cause a considerable exposure to benzene. Using a four-stroke engine equipped with a catalyst could reduce the exposure. To reduce the exposure for the passenger on a sleigh an extension of the exhaust pipe may be effective.

  7. Toluene and benzene inhalation influences on ventricular arrhythmias in the rat.

    PubMed

    Magos, G A; Lorenzana-Jiménez, M; Vidrio, H

    1990-01-01

    We have previously found that toluene did not share the capacity of benzene for increasing the arrhythmogenic action of epinephrine in the rat, but appeared to elicit the opposite effect. The present experiments were carried out to verify this observation in rats subjected to more severe ventricular arrhythmias. In animals previously inhaling either air, toluene or benzene and anesthetized with pentobarbital, arrhythmias were produced by coronary ligation or aconitine. In both models, toluene decreased and benzene increased the number of ectopic ventricular beats in the 30 min following induction of arrhythmia. Gas chromatographic measurement of toluene levels in the heart during and after inhalation revealed essentially constant concentrations at the time of arrhythmia evaluation, equivalent to approximately one-third the peak levels observed at the end of inhalation. Although the mechanism of the effect of toluene on arrhythmia could not be ascertained, nonspecific membrane stabilization or central serotonergic stimulation were considered as possible explanations. Since both mechanisms could be operant also in the case of benzene, the opposite effects of the solvents on arrhythmia could not be readily accounted for.

  8. Performance Basis for Airborne Separation

    NASA Technical Reports Server (NTRS)

    Wing, David J.

    2008-01-01

    Emerging applications of Airborne Separation Assistance System (ASAS) technologies make possible new and powerful methods in Air Traffic Management (ATM) that may significantly improve the system-level performance of operations in the future ATM system. These applications typically involve the aircraft managing certain components of its Four Dimensional (4D) trajectory within the degrees of freedom defined by a set of operational constraints negotiated with the Air Navigation Service Provider. It is hypothesized that reliable individual performance by many aircraft will translate into higher total system-level performance. To actually realize this improvement, the new capabilities must be attracted to high demand and complexity regions where high ATM performance is critical. Operational approval for use in such environments will require participating aircraft to be certified to rigorous and appropriate performance standards. Currently, no formal basis exists for defining these standards. This paper provides a context for defining the performance basis for 4D-ASAS operations. The trajectory constraints to be met by the aircraft are defined, categorized, and assessed for performance requirements. A proposed extension of the existing Required Navigation Performance (RNP) construct into a dynamic standard (Dynamic RNP) is outlined. Sample data is presented from an ongoing high-fidelity batch simulation series that is characterizing the performance of an advanced 4D-ASAS application. Data of this type will contribute to the evaluation and validation of the proposed performance basis.

  9. Biofiltration control of VOC emissions: Butane and benzene

    SciTech Connect

    Allen, E.R.

    1995-12-31

    Laboratory studies were conducted on the biological elimination of n-butane and benzene from air streams using activated sludge-treated compost biofilters. Four types of experimental biofilter systems were developed: a bench scale packed tower system used primarily for kinetic studies; a small scale column system used to study the effects of different filter media on n-butane removal; a three stage system used to study benzene elimination; and a static batch biofilter system used to study the effects of temperature, compost water content, compost pH, and initial benzene concentrations on benzene elimination. Removal efficiencies greater than 90% were obtained for n-butane. Removal followed first order kinetics at inlet concentrations less than 25 ppM n-butane and zero order kinetics above 100 ppM n-butane. Removal of benzene followed fractional order kinetics for inlet concentrations from 15 to 200 ppM benzene. Thus, the removal of benzene is both mass transfer and bioreaction limited for the concentration range studied. The removal efficiency of benzene was found to be highly dependent on compost water content, compost pH, and temperature. Compost showed a low capacity for benzene removal, which suggested that degradation of these hydrocarbons required different species of microorganisms.

  10. 40 CFR 80.1230 - What are the gasoline benzene requirements for refiners and importers?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false What are the gasoline benzene... Benzene Gasoline Benzene Requirements § 80.1230 What are the gasoline benzene requirements for refiners and importers? (a) Annual average benzene standard. (1) Except as specified in paragraph (c) of...

  11. 40 CFR 80.1238 - How is a refinery's or importer's average benzene concentration determined?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 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...

  12. 40 CFR 80.1230 - What are the gasoline benzene requirements for refiners and importers?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 17 2013-07-01 2013-07-01 false What are the gasoline benzene... Benzene Gasoline Benzene Requirements § 80.1230 What are the gasoline benzene requirements for refiners and importers? (a) Annual average benzene standard. (1) Except as specified in paragraph (c) of...

  13. 40 CFR 80.1230 - What are the gasoline benzene requirements for refiners and importers?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 17 2014-07-01 2014-07-01 false What are the gasoline benzene... Benzene Gasoline Benzene Requirements § 80.1230 What are the gasoline benzene requirements for refiners and importers? (a) Annual average benzene standard. (1) Except as specified in paragraph (c) of...

  14. 40 CFR 80.1238 - How is a refinery's or importer's average benzene concentration determined?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 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...

  15. 40 CFR 80.1238 - How is a refinery's or importer's average benzene concentration determined?

    Code of Federal Regulations, 2010 CFR

    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...

  16. 40 CFR 80.1235 - What gasoline is subject to the benzene requirements of this subpart?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... benzene requirements of this subpart? 80.1235 Section 80.1235 Protection of Environment ENVIRONMENTAL... Benzene Gasoline Benzene Requirements § 80.1235 What gasoline is subject to the benzene requirements of... not include the volume and benzene content of the oxygenate in any compliance calculations or...

  17. 40 CFR 80.1238 - How is a refinery's or importer's average benzene concentration determined?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 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...

  18. 40 CFR 80.1230 - What are the gasoline benzene requirements for refiners and importers?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 17 2012-07-01 2012-07-01 false What are the gasoline benzene... Benzene Gasoline Benzene Requirements § 80.1230 What are the gasoline benzene requirements for refiners and importers? (a) Annual average benzene standard. (1) Except as specified in paragraph (c) of...

  19. 40 CFR 80.1230 - What are the gasoline benzene requirements for refiners and importers?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 16 2011-07-01 2011-07-01 false What are the gasoline benzene... Benzene Gasoline Benzene Requirements § 80.1230 What are the gasoline benzene requirements for refiners and importers? (a) Annual average benzene standard. (1) Except as specified in paragraph (c) of...

  20. 40 CFR 80.1238 - How is a refinery's or importer's average benzene concentration determined?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 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...

  1. Hematotoxicity and carcinogenicity of inhaled benzene.

    PubMed

    Cronkite, E P; Drew, R T; Inoue, T; Hirabayashi, Y; Bullis, J E

    1989-07-01

    CBA/Ca male mice have been exposed to benzene in air at 10, 25, 100, 300, 400, and 3000 ppm for variable intervals 6 hr/day, 5 days/week for up to 16 weeks. Two weeks of inhaling 10 ppm produced no hematologic effects; 25 ppm induced a significant lymphopenia. Inhalation of 100, 300, and 400 ppm produced dose-dependent decreases in blood lymphocytes, bone marrow cellularity, marrow content of spleen colony-forming units (CFU-S) and an increased fraction of CFU-S in DNA synthesis. Exposure of mice to 300 ppm for 2, 4, 8, and 16 weeks produced severe lymphopenia and decrease in marrow CFU-S. Recovery was rapid and complete after 2 and 4 weeks of exposure. After 8 and 16 weeks of exposure, recovery of lymphocytes was complete within 8 weeks. It took 16 weeks for the CFU-S to recover to that of the age-matched controls after 8 weeks of exposure and 25 weeks to recover to age-matched after 16 weeks of exposure. Inhalation of 3000 ppm for 8 days was less damaging than inhalation of 300 ppm for 80 days (same integral amount of benzene inhaled). The inhalation of 3000 ppm has not increased the incidence of leukemia or shortened its latency for development. Inhalation of 300 ppm 6 hr/day for 16 weeks significantly increases the incidence of myelogenous neoplasms in male CBA/Ca mice. Inhalation of 100 ppm for same interval does not influence incidence of myelogenous neoplasms but does increase incidence of solid neoplasms particularly in female CBA/Ca mice. Benzene is a potent carcinogen in CBA/Ca mice.

  2. Characterization of airborne bacteria at an underground subway station.

    PubMed

    Dybwad, Marius; Granum, Per Einar; Bruheim, Per; Blatny, Janet Martha

    2012-03-01

    The reliable detection of airborne biological threat agents depends on several factors, including the performance criteria of the detector and its operational environment. One step in improving the detector's performance is to increase our knowledge of the biological aerosol background in potential operational environments. Subway stations are enclosed public environments, which may be regarded as potential targets for incidents involving biological threat agents. In this study, the airborne bacterial community at a subway station in Norway was characterized (concentration level, diversity, and virulence- and survival-associated properties). In addition, a SASS 3100 high-volume air sampler and a matrix-assisted laser desorption ionization-time of flight mass spectrometry-based isolate screening procedure was used for these studies. The daytime level of airborne bacteria at the station was higher than the nighttime and outdoor levels, and the relative bacterial spore number was higher in outdoor air than at the station. The bacterial content, particle concentration, and size distribution were stable within each environment throughout the study (May to September 2010). The majority of the airborne bacteria belonged to the genera Bacillus, Micrococcus, and Staphylococcus, but a total of 37 different genera were identified in the air. These results suggest that anthropogenic sources are major contributors to airborne bacteria at subway stations and that such airborne communities could harbor virulence- and survival-associated properties of potential relevance for biological detection and surveillance, as well as for public health. Our findings also contribute to the development of realistic testing and evaluation schemes for biological detection/surveillance systems by providing information that can be used to mimic real-life operational airborne environments in controlled aerosol test chambers. PMID:22247150

  3. Characterization of Airborne Bacteria at an Underground Subway Station

    PubMed Central

    Dybwad, Marius; Granum, Per Einar; Bruheim, Per

    2012-01-01

    The reliable detection of airborne biological threat agents depends on several factors, including the performance criteria of the detector and its operational environment. One step in improving the detector's performance is to increase our knowledge of the biological aerosol background in potential operational environments. Subway stations are enclosed public environments, which may be regarded as potential targets for incidents involving biological threat agents. In this study, the airborne bacterial community at a subway station in Norway was characterized (concentration level, diversity, and virulence- and survival-associated properties). In addition, a SASS 3100 high-volume air sampler and a matrix-assisted laser desorption ionization–time of flight mass spectrometry-based isolate screening procedure was used for these studies. The daytime level of airborne bacteria at the station was higher than the nighttime and outdoor levels, and the relative bacterial spore number was higher in outdoor air than at the station. The bacterial content, particle concentration, and size distribution were stable within each environment throughout the study (May to September 2010). The majority of the airborne bacteria belonged to the genera Bacillus, Micrococcus, and Staphylococcus, but a total of 37 different genera were identified in the air. These results suggest that anthropogenic sources are major contributors to airborne bacteria at subway stations and that such airborne communities could harbor virulence- and survival-associated properties of potential relevance for biological detection and surveillance, as well as for public health. Our findings also contribute to the development of realistic testing and evaluation schemes for biological detection/surveillance systems by providing information that can be used to mimic real-life operational airborne environments in controlled aerosol test chambers. PMID:22247150

  4. Airborne Particulate Threat Assessment

    SciTech Connect

    Patrick Treado; Oksana Klueva; Jeffrey Beckstead

    2008-12-31

    Aerosol threat detection requires the ability to discern between threat agents and ambient background particulate matter (PM) encountered in the environment. To date, Raman imaging technology has been demonstrated as an effective strategy for the assessment of threat agents in the presence of specific, complex backgrounds. Expanding our understanding of the composition of ambient particulate matter background will improve the overall performance of Raman Chemical Imaging (RCI) detection strategies for the autonomous detection of airborne chemical and biological hazards. Improving RCI detection performance is strategic due to its potential to become a widely exploited detection approach by several U.S. government agencies. To improve the understanding of the ambient PM background with subsequent improvement in Raman threat detection capability, ChemImage undertook the Airborne Particulate Threat Assessment (APTA) Project in 2005-2008 through a collaborative effort with the National Energy Technology Laboratory (NETL), under cooperative agreement number DE-FC26-05NT42594. During Phase 1 of the program, a novel PM classification based on molecular composition was developed based on a comprehensive review of the scientific literature. In addition, testing protocols were developed for ambient PM characterization. A signature database was developed based on a variety of microanalytical techniques, including scanning electron microscopy, FT-IR microspectroscopy, optical microscopy, fluorescence and Raman chemical imaging techniques. An automated particle integrated collector and detector (APICD) prototype was developed for automated collection, deposition and detection of biothreat agents in background PM. During Phase 2 of the program, ChemImage continued to refine the understanding of ambient background composition. Additionally, ChemImage enhanced the APICD to provide improved autonomy, sensitivity and specificity. Deliverables included a Final Report detailing our

  5. Pnictogen-Silicon Analogues of Benzene.

    PubMed

    Seitz, Andreas E; Eckhardt, Maria; Erlebach, Andreas; Peresypkina, Eugenia V; Sierka, Marek; Scheer, Manfred

    2016-08-24

    Since the discovery of the first "inorganic benzene" (borazine, B3N3H6), the synthesis of other noncarbon derivatives is an ongoing challenge in Inorganic Chemistry. Here we report on the synthesis of the first pnictogen-silicon congeners of benzene, the triarsa- and the triphospha-trisilabenzene [(PhC(NtBu)2)3Si3E3] (E = P (1a), As (1b)) by a simple metathesis reaction. These compounds are formed by the reaction of [Cp″2Zr(η(1:1)-E4)] (E = P, As; Cp″ = C5H3tBu2) with [PhC(NtBu)2SiCl] in toluene at room temperature along with the silicon pnictogen congeners of the cyclobutadiene, [(PhC(NtBu)2)2Si2E2] (E = P (2a), As (2b)), which is unprecedented for the arsenic system 2b. All compounds were comprehensively characterized, and density functional theory calculations were performed to verify the stability and the aromatic character of the triarsa- and the triphospha-trisilabenzene. PMID:27513314

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

    PubMed Central

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

    2015-01-01

    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 Notch1 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. PMID:26262635

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

    PubMed

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

    2015-08-07

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

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

    PubMed

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

    2014-03-01

    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 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, our published work has applied innovative in vitro functional genomics testing systems, including unbiased functional screening assays in yeast and a near-haploid human bone marrow cell line. Through comparative genomic and computational analyses of the resulting data, human genes and pathways that may modulate susceptibility to benzene and formaldehyde were identified, and the roles of several genes in mammalian cell models were validated. In populations occupationally exposed to low levels of benzene, we applied peripheral blood mononuclear cell transcriptomics and chromosome-wide aneuploidy studies in lymphocytes. In this review, 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.

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

    PubMed Central

    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

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

    PubMed Central

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

    2015-01-01

    Background: The aim of this work was to examine the risk of lymphohaematopoietic (LH) cancer according to benzene exposure among offshore workers. Methods: Cancer registry data were used to identify 112 cancer cases diagnosed during 1999–2011 in a cohort of 24 917 Norwegian men reporting offshore work between 1965 and 1999. Analyses were conducted according to a stratified case–cohort design with a reference subcohort of 1661 workers. Cox regression was used to estimate hazard ratios with 95% confidence intervals, adjusted for other benzene exposure and smoking. Results: Most workers were exposed to benzene for <15 years. The upper range values of average intensity and cumulative exposure were estimated to 0.040 p.p.m. and 0.948 p.p.m.-years, respectively. Risks were consistently elevated among exposed workers for all LH cancers combined and for most subgroups, although case numbers were small and yielded imprecise risk estimates. There was evidence of dose-related risk patterns according to cumulative exposure for acute myeloid leukaemia (AML), multiple myeloma (MM) (P trends 0.052 and 0.024, respectively), and suggestively so for chronic lymphocytic leukaemia (CLL) according to average intensity (P trend 0.094). Conclusions: Our results support an association between cumulative and intensity metrics of low-level benzene exposure and risk for AML, MM, and suggestively for CLL. PMID:25867262

  11. Pulsed Doppler lidar airborne scanner

    NASA Technical Reports Server (NTRS)

    Dimarzio, C. A.; Mcvicker, D. B.; Morrow, C. E.; Negus, C. C.

    1985-01-01

    This report covers the work accomplished during the reporting period on Pulsed Doppler Lidar Airborne Scanner and describes plans for the next reporting period. The objectives during the current phase of the contract are divided into four phases. Phase 1 includes ground testing of the system and analysis of data from the 1981 Severe Storms Test Flights. Phase 2 consists of preflight preparation and planning for the 1983 flight series. The flight test itself will be performed during Phase 3, and Phase 4 consists of post-flight analysis and operation of the system after that flight test. The range profile from five samples taken during Flight 10, around 1700 Z is given. The lowest curve is taken from data collected upwind of Mt. Shasta at about 10,000 feet of altitude, in a clear atmosphere, where no signals were observed. It thus is a good representation of the noise level as a function of range. The next curve was taken downwind of the mountain, and shows evidence of atmospheric returns. There is some question as to whether the data are valid at all ranges, or some ranges are contaminated by the others.

  12. Airborne GLM Simulator (FEGS)

    NASA Astrophysics Data System (ADS)

    Quick, M.; Blakeslee, R. J.; Christian, H. J., Jr.; Stewart, M. F.; Podgorny, S.; Corredor, D.

    2015-12-01

    Real time lightning observations have proven to be useful for advanced warning and now-casting of severe weather events. In anticipation of the launch of the Geostationary Lightning Mapper (GLM) onboard GOES-R that will provide continuous real time observations of total (both cloud and ground) lightning, the Fly's Eye GLM Simulator (FEGS) is in production. FEGS is an airborne instrument designed to provide cal/val measurements for GLM from high altitude aircraft. It consists of a 5 x 5 array of telescopes each with a narrow passband filter to isolate the 777.4 nm neutral oxygen emission triplet radiated by lightning. The telescopes will measure the optical radiance emitted by lightning that is transmitted through the cloud top with a temporal resolution of 10 μs. When integrated on the NASA ER-2 aircraft, the FEGS array with its 90° field-of-view will observe a cloud top area nearly equal to a single GLM pixel. This design will allow FEGS to determine the temporal and spatial variation of light that contributes to a GLM event detection. In addition to the primary telescope array, the instrument includes 5 supplementary optical channels that observe alternate spectral emission features and will enable the use of FEGS for interesting lightning physics applications. Here we present an up-to-date summary of the project and a description of its scientific applications.

  13. Selection of respiratory protection devices for use in very high concentrations of airborne plutonium.

    PubMed

    Bianconi, C J

    2000-08-01

    This paper focuses on the proper selection of respiratory protection devices for use in very high concentrations of airborne plutonium. Special attention is given to the determination of levels at which airborne plutonium presents a hazard that is immediately dangerous to life or health. PMID:10910403

  14. Mobil-Badger technologies for benzene reduction in gasoline

    SciTech Connect

    Goelzer, A.R.; Ram, S.; Hernandez, A. ); Chin, A.A.; Harandi, M.N.; Smith, C.M. Mobil Research and Development Corp., Paulsboro, NJ )

    1993-01-01

    Many refiners will need to reduce the barrels per day of benzene entering the motor gasoline pool. Mobil and Badger have developed and now jointly license three potential refinery alternatives to conventional benzene hydrosaturation to achieve this: Mobil Benzene Reduction, Ethylbenzene and Cumene. The Mobil Benzene Reduction Process (MBR) uses dilute olefins in FCC offgas to extensively alkylate dilute benzene as found in light reformate, light FCC gasoline, or cyclic C[sub 6] naphtha. MBR raises octanes and lowers C[sub 5]+ olefins. MBR does not involve costly hydrogen addition. The refinery-based Mobil/Badger Ethylbenzene Process reacts chemical-grade benzene extracted from light reformate with dilute ethylene found in treated FCC offgas to make high-purity ethylbenzene. EB is the principal feedstock for the production of styrene. The Mobil/Badger Cumene Process alkylates FCC-derived dilute propylene and extracted benzene to selectively yield isopropyl benzene (cumene). Cumene is the principal feedstock for the production of phenol. All three processes use Mobil developed catalysts.

  15. REACTION OF BENZENE OXIDE WITH THIOLS INCLUDING GLUTATHIONE

    EPA Science Inventory

    This study accounts for the observations that the metabolism of benzene is dominated by the formation of phenol. As demonstrated here, the pathway leading to S-phenylmercapturic acid is necessarily minor on account of the low efficiency of benzene oxide capture by glutathione at ...

  16. Detection and identification of toxic air pollutants using airborne LWIR hyperspectral imaging

    NASA Astrophysics Data System (ADS)

    Williams, David J.; Feldman, Barry L.; Williams, Tim J.; Pilant, Drew; Lucey, Paul G.; Worthy, L. D.

    2005-01-01

    Airborne longwave infrared (LWIR) hyperspectral imagery was utilized to detect and identify gaseous chemical release plumes at sites in southern Texas. The Airborne Hyperspectral Imager (AHI), developed by the University of Hawai"i, was flown over a petrochemical facility and a confined animal feeding operation on a modified DC-3 during April, 2004. Data collected by the AHI system was successfully used to detect and identify numerous plumes at both sites. Preliminary results indicate the presence of benzene and ammonia and several other organic compounds. Emissions were identified using regression analysis on atmospherically compensated data. Data validation was conducted using facility emission inventories. This technology has great promise for monitoring and inventorying facility emissions, and may be used as means to assist ground inspection teams to focus on actual fugitive emission points.

  17. Adsorption of simple benzene derivatives on carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Woods, L. M.; Bădescu, Ş. C.; Reinecke, T. L.

    2007-04-01

    The adsorption of simple benzene derivatives composed of a benzene ring with NO2 , CH3 , or NH2 functional groups on a semiconducting single-wall carbon nanotube is studied using the density-functional theory within the local-density approximation. The effects of molecular relaxation in the adsorption process are obtained, as well as the adsorption energies and equilibrium distances for several molecular locations and orientations on the surface. We find that all of these benzene derivatives are physisorbed mainly through the interaction of the π orbitals of the benzene ring and those of the carbon nanotube. These aromatics do not change significantly the carbon nanotube’s electronic structure, and therefore only small changes in the nanotube’s properties are expected. This suggests that these benzene derivatives are suitable for noncovalent nanotube functionalization and molecule immobilization on nanotube surfaces.

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

    DOEpatents

    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.

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

    DOEpatents

    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.

  20. Different aggregation dynamics of benzene-water mixtures.

    PubMed

    Fu, Cen-Feng; Tian, Shan Xi

    2014-10-28

    All-atom molecular dynamics simulations for benzene-water mixtures are performed, aiming to explore the relationship between the microscopic structures and the thermodynamic properties, in particular, the transformation dynamics from the mutually soluble state to the phase-separated state. We find that the molecular aggregation of benzene in the water-rich mixture is distinctly different from that of water in the benzene-rich mixture. This aggregation difference is attributed to the different intermolecular interactions: the clustering of benzene molecules in the water-rich mixture is primarily driven by weak short-distance π-π interactions; while the formation of water clusters in the benzene-rich solution is triggered by long-range dipole-dipole electrostatic interactions. Moreover, the molecular aggregations show double-scaled features: firstly assembling in a quasi-plane at a low concentration, then bulking in three dimensions with an increase in concentration.

  1. Longitudinal study of dust and airborne endotoxin in the home.

    PubMed

    Park, J H; Spiegelman, D L; Burge, H A; Gold, D R; Chew, G L; Milton, D K

    2000-11-01

    To characterize the seasonal variability of endotoxin levels, we measured endotoxin in dust from the bed, bedroom floor, and kitchen floor in 20 homes, and in air from the bedroom in 15 of the homes. All homes were located in the greater Boston, Massachusetts, area and were sampled each month from April 1995 to June 1996. Outdoor air was collected at two locations. We found greater within-home than between-home variance for bedroom floor, kitchen floor, and airborne endotoxin. However, the reverse was true for bed dust endotoxin. Thus, studies using single measurements of dust endotoxin are most likely to reliably distinguish between homes if bed dust is sampled. Dust endotoxin levels were not significantly associated with airborne endotoxin. Airborne endotoxin was significantly (p = 0. 04) and positively associated with absolute humidity in a mixed-effect model adjusting for a random home effect and fixed effect of sampling month and home characteristics. This finding implies that indoor humidity may be an important factor controlling endotoxin exposure. We found a significant (p < 0.05) seasonal effect in kitchen floor dust (spring > fall) and bedroom airborne endotoxin (spring > winter), but not in the other indoor samples. We found significant seasonal pattern in outdoor airborne endotoxin (summer > winter). PMID:11102291

  2. Anaerobic degradation of benzene by marine sulfate-reducing bacteria

    NASA Astrophysics Data System (ADS)

    Musat, Florin; Wilkes, Heinz; Musat, Niculina; Kuypers, Marcel; Widdel, Friedrich

    2010-05-01

    Benzene, the archetypal aromatic hydrocarbon is a common constituent of crude oil and oil-refined products. As such, it can enter the biosphere through natural oil seeps or as a consequence of exploitation of fossil fuel reservoirs. Benzene is chemically very stable, due to the stabilizing aromatic electron system and to the lack of functional groups. Although the anaerobic degradation of benzene has been reported under denitrifying, sulfate-reducing and methanogenic conditions, the microorganisms involved and the initial biochemical steps of degradation remain insufficiently understood. Using marine sediment from a Mediterranean lagoon a sulfate-reducing enrichment culture with benzene as the sole organic substrate was obtained. Application of 16S rRNA gene-based methods showed that the enrichment was dominated (more than 85% of total cells) by a distinct phylotype affiliated with a clade of Deltaproteobacteria that include degraders of other aromatic hydrocarbons, such as naphthalene, ethylbenzene and m-xylene. Using benzoate as a soluble substrate in agar dilution series, several pure cultures closely related to Desulfotignum spp. and Desulfosarcina spp. were isolated. None of these strains was able to utilize benzene as a substrate and hybridizations with specific oligonucleotide probes showed that they accounted for as much as 6% of the total cells. Incubations with 13C-labeled benzene followed by Halogen in situ Hybridization - Secondary Ion Mass Spectroscopy (HISH-SIMS) analysis showed that cells of the dominant phylotype were highly enriched in 13C, while the accompanying bacteria had little or no 13C incorporation. These results demonstrate that the dominant phylotype was indeed the apparent benzene degrader. Dense-cell suspensions of the enrichment culture did not show metabolic activity toward added phenol or toluene, suggesting that benzene degradation did not proceed through anaerobic hydroxylation or methylation. Instead, benzoate was identified in

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

    ERIC Educational Resources Information Center

    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.

  4. Airborne Laser Polar Nephelometer

    NASA Technical Reports Server (NTRS)

    Grams, Gerald W.

    1973-01-01

    A polar nephelometer has been developed at NCAR to measure the angular variation of the intensity of light scattered by air molecules and particles. The system has been designed for airborne measurements using outside air ducted through a 5-cm diameter airflow tube; the sample volume is that which is common to the intersection of a collimated source beam and the detector field of view within the airflow tube. The source is a linearly polarized helium-neon laser beam. The optical system defines a collimated field-of-view (0.5deg half-angle) through a series of diaphragms located behind a I72-mm focal length objective lens. A photomultiplier tube is located immediately behind an aperture in the focal plane of the objective lens. The laser beam is mechanically chopped (on-off) at a rate of 5 Hz; a two-channel pulse counter, synchronized to the laser output, measures the photomultiplier pulse rate with the light beam both on and off. The difference in these measured pulse rates is directly proportional to the intensity of the scattered light from the volume common to the intersection of the laser beam and the detector field-of-view. Measurements can be made at scattering angles from 15deg to 165deg with reference to the direction of propagation of the light beam. Intermediate angles are obtained by selecting the angular increments desired between these extreme angles (any multiple of 0.1deg can be selected for the angular increment; 5deg is used in normal operation). Pulses provided by digital circuits control a stepping motor which sequentially rotates the detector by pre-selected angular increments. The synchronous photon-counting system automatically begins measurement of the scattered-light intensity immediately after the rotation to a new angle has been completed. The instrument has been flown on the NASA Convair 990 airborne laboratory to obtain data on the complex index of refraction of atmospheric aerosols. A particle impaction device is operated simultaneously

  5. Methyl tunnelling in trihalogeno-trimethyl-benzenes

    NASA Astrophysics Data System (ADS)

    Meinnel, J.; Häusler, W.; Mani, M.; Tazi, M.; Nusimovici, M.; Sanquer, M.; Wyncke, B.; Heidemann, A.; Carlile, C. J.; Tomkinson, J.; Hennion, B.

    1992-06-01

    Results of inelastic neutron scattering (INS) from 1,3,5-trihalogeno-2,4,6-trimethyl-benzenes are reported for the chloro-, the bromo- and the iodo-case. For the whole family the spectra show numerous similarities, in the μeV as well as in the meV range. We observe three tunnelling lines of equal intensity corresponding to three crystallographically inequivalent methyl rotors. The observed librational peaks are at much lower energies than expected from a pure threefold potential. Within the halogen family a systematic reduction of the barrier height is found with larger halogen sizes. The temperature dependence of the tunnelling energies shows the most pronounced difference between TBM and TIM, where the corresponding tunnelling lines even shift in opposite directions.

  6. Toxicity of chlorinated benzenes to marine algae

    NASA Astrophysics Data System (ADS)

    Ma, Yan-Jun; Wang, Xiu-Lin; Yu, Wei-Jun; Zhang, Li-Jun; Sun, Han-Zhang

    1997-12-01

    Growth of Chlorella marine, Nannochloropsis oculata, Pyramidomonas sp., Platymonas subcordiformis and Phaeodactylum tricornutum exposed to monochlorobenzene (MCB), 1,2-dichlorobenzene (1,2-DCB), 1, 2, 3, 4-tetrachlorobenzene (1, 2, 3, 4-TeCB) and pentachlorobenzene (PeCB) was tested. Tests of 72 h- EC 50 values showed that the toxicity ranged in the order: MCB<1,2-DCB<1,2,3,4-TeCBbenzene (CB) alone to marine algae was almost in the order: Pyramidomonas sp. < Platymonas subcordiformis < Nannochloropsis oculata < Chlorella marine < Phaeodactylum tricomutum. Study of the QSAR (Quantitative Structure-Activity Relationship) between K OW and toxicity of CBs to marine algae showed good relationships between -log EC 50 and log K OW.

  7. Detailed mechanism for oxidation of benzene

    NASA Technical Reports Server (NTRS)

    Bittker, David A.

    1990-01-01

    A detailed mechanism for the oxidation of benzene is presented and used to compute experimentally obtained concentration profiles and ignition delay times over a wide range of equivalence ratio and temperature. The computed results agree qualitatively with all the experimental trends. Quantitative agreement is obtained with several of the composition profiles and for the temperature dependence of the ignition delay times. There are indications, however, that some important reactions are as yet undiscovered in this mechanism. Recent literature expressions have been used for the rate coefficients of most important reactions, except for some involving phenol. The discrepancy between the phenol pyrolysis rate coefficient used in this work and a recent literature expression remains to be explained.

  8. Electroanalytical approaches to understanding benzene metabolism.

    PubMed

    Lunte, S M; Lunte, C E

    1990-01-01

    Electrochemical techniques are ideally suited to the study of the metabolism of aromatic xenobiotics because the metabolites are frequently easier to oxidize than the parent compounds. In many cases, the trace metabolites have the lowest oxidation potentials and hence electrochemical methods have the greatest selectivity for these compounds. The sensitivity of dual-electrode liquid chromatography-electrochemistry for the detection and identification of trace metabolites was demonstrated by the detection of the secondary metabolite, hydroquinone, in a microsomal incubation containing benzene and ascorbic acid. The use of an electrochemical detector in a series configuration provides increased selectivity for chemically reversible metabolites such as hydroquinone. Electrochemical methods can also be used to generate metabolites. The products of the electrochemical oxidation of phenol and biphenol are compared with those generated in a peroxidase incubation.

  9. Emissions of volatile organic compounds inferred from airborne flux measurements over a megacity

    NASA Astrophysics Data System (ADS)

    Karl, T.; Apel, E.; Hodzic, A.; Riemer, D. D.; Blake, D. R.; Wiedinmyer, C.

    2009-01-01

    Toluene and benzene are used for assessing the ability to measure disjunct eddy covariance (DEC) fluxes of Volatile Organic Compounds (VOC) using Proton Transfer Reaction Mass Spectrometry (PTR-MS) on aircraft. Statistically significant correlation between vertical wind speed and mixing ratios suggests that airborne VOC eddy covariance (EC) flux measurements using PTR-MS are feasible. City-median midday toluene and benzene fluxes are calculated to be on the order of 14.1±4.0 mg/m2/h and 4.7±2.3 mg/m2/h, respectively. For comparison the adjusted CAM2004 emission inventory estimates toluene fluxes of 10 mg/m2/h along the footprint of the flight-track. Wavelet analysis of instantaneous toluene and benzene measurements during city overpasses is tested as a tool to assess surface emission heterogeneity. High toluene to benzene flux ratios above an industrial district (e.g. 10-15 g/g) including the International airport (e.g. 3-5 g/g) and a mean flux (concentration) ratio of 3.2±0.5 g/g (3.9±0.3 g/g) across Mexico City indicate that evaporative fuel and industrial emissions play an important role for the prevalence of aromatic compounds. Based on a tracer model, which was constrained by BTEX (BTEX- Benzene/Toluene/Ethylbenzene/m, p, o-Xylenes) compound concentration ratios, the fuel marker methyl-tertiary-butyl-ether (MTBE) and the biomass burning marker acetonitrile (CH3CN), we show that a combination of industrial, evaporative fuel, and exhaust emissions account for >87% of all BTEX sources. Our observations suggest that biomass burning emissions play a minor role for the abundance of BTEX compounds in the MCMA (2-13%).

  10. Mapping methane sources and emissions over California from direct airborne flux and VOC source tracer measurements

    NASA Astrophysics Data System (ADS)

    Guha, A.; Misztal, P. K.; Peischl, J.; Karl, T.; Jonsson, H. H.; Woods, R. K.; Ryerson, T. B.; Goldstein, A. H.

    2013-12-01

    fluxes were obtained using the virtual disjunct eddy covariance method and from Wavelet Analysis along flight tracks flown in the mixed layer. Preliminary analysis of mixing ratio measurements indicate that high concentrations of CH4 occur consistently while flying above the Central Valley that are correlated to large enhancements of methanol which is an important dairy and livestock emissions tracer. The elevated CH4 mixing ratios along the eastern edge of the San Joaquin Valley highlight the contribution of topography and emissions transport to local ambient levels of CH4. Large enhancements of CH4, benzene and toluene are also observed while flying over the oil production facilities in western part of Kern county (state's top oil producing county, 10% of US production) suggesting the likelihood of fugitive emissions in the region. VOC tracer analysis is used to evaluate the source of high CH4 emissions encountered along the eastern edge of the central Sacramento valley where fugitive emissions from natural gas fields and cultivation of rice are likely sources. Plumes from biomass burning, landfills and refineries encountered during different flights are also investigated. Eddy covariance based CH4 flux estimates are derived for various sources and compared with ';bottom-up' inventory estimates to verify/validate the CA methane inventory for major sources.

  11. Benzene, toluene and C 2-benzene emissions of 4-stroke motorbikes: Benefits and risks of the current TWC technology

    NASA Astrophysics Data System (ADS)

    Saxer, Christian J.; Forss, Anna-Maria; Rüdy, Claudio; Heeb, Norbert V.

    Chemical ionization mass spectrometry has been applied to determine benzene, toluene and C 2-benzene emission rates of 4-stroke motorbikes. Extra emissions and duration of the cold start were deduced from the legislative urban driving cycle. The Common Artemis driving cycle was investigated to study the emission characteristics at transient driving from 0 to 135 km h -1. In addition, the benefits and risks of the currently available 3-way catalyst technology (TWC) are explored. Benzene, toluene and C 2-benzene cold start emissions of 230-290, 920-980 and 950-1270 mg start -1 were obtained for the TWC motorbikes, exceeding those without catalyst by more than a factor of 3. At hot engine/catalyst, benzene, toluene and C 2-benzene emission factors in the range of 10-140, 10-160 and 10-170 mg km -1 were found for the TWC motorbikes. Without catalyst, the corresponding emission factors were higher, varying from 40 to 260, 100 to 500 and 110 to 480 mg km -1, respectively. A comparison with the latest passenger car technology, with reported aromatic hydrocarbon (HC) emission factors of 0.2-3.0 mg km -1, revealed that the investigated 4-stroke motorbikes, indeed, are an important source of air pollution. Furthermore, cold start duration, driving distance under cold start influence and velocity dependence of aromatic HC emissions were deduced from time-resolved data. In addition, variations of aromatic HC mixing ratios were studied. Narrow and unimodal distributions of, e.g. benzene/C 2-benzene mixing ratios with median values of 0.46-0.73 were found for all motorbikes but one. This motorcycle, equipped with a TWC, showed a broad and bimodal distribution with a median mixing ratio of 1.47. Catalyst-induced formation of benzene from alkylbenzenes is the assumed process, leading to increased benzene/alkylbenzene mixing ratios.

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

    PubMed

    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.

  13. Airborne laser topographic mapping results

    NASA Technical Reports Server (NTRS)

    Krabill, W. B.; Collins, J. G.; Link, L. E.; Swift, R. N.; Butler, M. L.

    1984-01-01

    The results of terrain mapping experiments utilizing the National Aeronautics and Space Administration (NASA) Airborne Oceanographic Lidar (AOL) over forested areas are presented. The flight tests were conducted as part of a joint NASA/U.S. Army Corps of Engineers (CE) investigation aimed at evaluating the potential of an airborne laser ranging system to provide cross-sectional topographic data on flood plains that are difficult and expensive to survey using conventional techniques. The data described in this paper were obtained in the Wolf River Basin located near Memphis, TN. Results from surveys conducted under winter 'leaves off' and summer 'leaves on' conditions, aspects of day and night operation, and data obtained from decidous and coniferous tree types are compared. Data processing techniques are reviewed. Conclusions relative to accuracy and present limitations of the AOL, and airborne lidar systems in general, to terrain mapping over forested areas are discussed.

  14. An airborne isothermal haze chamber

    NASA Technical Reports Server (NTRS)

    Hindman, E. E.

    1981-01-01

    Thermal gradient diffusion cloud chambers (TGDCC) are used to determine the concentrations of cloud condensation nuclei (CCN) with critical supersaturations greater than or equal to about 0.2%. The CCN concentrations measured with the airborne IHC were lower than theoretically predicted by factors ranging between 7.9 and 9.0. The CCN concentrations measured with the airborne IHC were lower than the concentrations measured with the larger laboratory IHC's by factors ranging between 3.9 and 7.5. The bounds of the supersaturation ranges of the airborne IHC and the CSU-Mee TGDCC do not overlap. Nevertheless, the slopes of the interpolated data between the bounds agree favorably with the theoretical slopes.

  15. WESTERN AIRBORNE CONTAMINANTS ASSESSMENT PROJECT RESEARCH PLAN

    EPA Science Inventory

    The goal of the Western Airborne Contaminants Assessment Project (WACAP) is to assess the deposition of airborne contaminants in Western National Parks, providing regional and local information on exposure, accumulation, impacts, and probable sources. This project is being desig...

  16. Biophysical influence of airborne carbon nanomaterials on natural pulmonary surfactant.

    PubMed

    Valle, Russell P; Wu, Tony; Zuo, Yi Y

    2015-05-26

    Inhalation of nanoparticles (NP), including lightweight airborne carbonaceous nanomaterials (CNM), poses a direct and systemic health threat to those who handle them. Inhaled NP penetrate deep pulmonary structures in which they first interact with the pulmonary surfactant (PS) lining at the alveolar air-water interface. In spite of many research efforts, there is a gap of knowledge between in vitro biophysical study and in vivo inhalation toxicology since all existing biophysical models handle NP-PS interactions in the liquid phase. This technical limitation, inherent in current in vitro methodologies, makes it impossible to simulate how airborne NP deposit at the PS film and interact with it. Existing in vitro NP-PS studies using liquid-suspended particles have been shown to artificially inflate the no-observed adverse effect level of NP exposure when compared to in vivo inhalation studies and international occupational exposure limits (OELs). Here, we developed an in vitro methodology called the constrained drop surfactometer (CDS) to quantitatively study PS inhibition by airborne CNM. We show that airborne multiwalled carbon nanotubes and graphene nanoplatelets induce a concentration-dependent PS inhibition under physiologically relevant conditions. The CNM aerosol concentrations controlled in the CDS are comparable to those defined in international OELs. Development of the CDS has the potential to advance our understanding of how submicron airborne nanomaterials affect the PS lining of the lung.

  17. Airborne Transmission of Bordetella pertussis

    PubMed Central

    Warfel, Jason M.; Beren, Joel; Merkel, Tod J.

    2012-01-01

    Pertussis is a contagious, acute respiratory illness caused by the bacterial pathogen Bordetella pertussis. Although it is widely believed that transmission of B. pertussis occurs via aerosolized respiratory droplets, no controlled study has ever documented airborne transmission of pertussis. We set out to determine if airborne transmission occurs between infected and naive animals, utilizing the baboon model of pertussis. Our results showed that 100% of exposed naive animals became infected even when physical contact was prevented, demonstrating that pertussis transmission occurs via aerosolized respiratory droplets. PMID:22807521

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

    PubMed Central

    Weisel, Clifford P.

    2014-01-01

    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 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

  19. The contribution of benzene to smoking-induced leukemia.

    PubMed

    Korte, J E; Hertz-Picciotto, I; Schulz, M R; Ball, L M; Duell, E J

    2000-04-01

    Cigarette smoking is associated with an increased risk of leukemia; benzene, an established leukemogen, is present in cigarette smoke. By combining epidemiologic data on the health effects of smoking with risk assessment techniques for low-dose extrapolation, we assessed the proportion of smoking-induced total leukemia and acute myeloid leukemia (AML) attributable to the benzene in cigarette smoke. We fit both linear and quadratic models to data from two benzene-exposed occupational cohorts to estimate the leukemogenic potency of benzene. Using multiple-decrement life tables, we calculated lifetime risks of total leukemia and AML deaths for never, light, and heavy smokers. We repeated these calculations, removing the effect of benzene in cigarettes based on the estimated potencies. From these life tables we determined smoking-attributable risks and benzene-attributable risks. The ratio of the latter to the former constitutes the proportion of smoking-induced cases attributable to benzene. Based on linear potency models, the benzene in cigarette smoke contributed from 8 to 48% of smoking-induced total leukemia deaths [95% upper confidence limit (UCL), 20-66%], and from 12 to 58% of smoking-induced AML deaths (95% UCL, 19-121%). The inclusion of a quadratic term yielded results that were comparable; however, potency models with only quadratic terms resulted in much lower attributable fractions--all < 1%. Thus, benzene is estimated to be responsible for approximately one-tenth to one-half of smoking-induced total leukemia mortality and up to three-fifths of smoking-related AML mortality. In contrast to theoretical arguments that linear models substantially overestimate low-dose risk, linear extrapolations from empirical data over a dose range of 10- to 100-fold resulted in plausible predictions. PMID:10753092

  20. The contribution of benzene to smoking-induced leukemia.

    PubMed Central

    Korte, J E; Hertz-Picciotto, I; Schulz, M R; Ball, L M; Duell, E J

    2000-01-01

    Cigarette smoking is associated with an increased risk of leukemia; benzene, an established leukemogen, is present in cigarette smoke. By combining epidemiologic data on the health effects of smoking with risk assessment techniques for low-dose extrapolation, we assessed the proportion of smoking-induced total leukemia and acute myeloid leukemia (AML) attributable to the benzene in cigarette smoke. We fit both linear and quadratic models to data from two benzene-exposed occupational cohorts to estimate the leukemogenic potency of benzene. Using multiple-decrement life tables, we calculated lifetime risks of total leukemia and AML deaths for never, light, and heavy smokers. We repeated these calculations, removing the effect of benzene in cigarettes based on the estimated potencies. From these life tables we determined smoking-attributable risks and benzene-attributable risks. The ratio of the latter to the former constitutes the proportion of smoking-induced cases attributable to benzene. Based on linear potency models, the benzene in cigarette smoke contributed from 8 to 48% of smoking-induced total leukemia deaths [95% upper confidence limit (UCL), 20-66%], and from 12 to 58% of smoking-induced AML deaths (95% UCL, 19-121%). The inclusion of a quadratic term yielded results that were comparable; however, potency models with only quadratic terms resulted in much lower attributable fractions--all < 1%. Thus, benzene is estimated to be responsible for approximately one-tenth to one-half of smoking-induced total leukemia mortality and up to three-fifths of smoking-related AML mortality. In contrast to theoretical arguments that linear models substantially overestimate low-dose risk, linear extrapolations from empirical data over a dose range of 10- to 100-fold resulted in plausible predictions. PMID:10753092

  1. Column Closure Studies of Lower Tropospheric Aerosol and Water Vapor During ACE-Asia Using Airborne Sunphotometer, Airborne In-Situ and Ship-Based Lidar Measurements

    NASA Technical Reports Server (NTRS)

    Schmid, B.; Hegg, A.; Wang, J.; Bates, D.; Redemann, J.; Russells, P. B.; Livingston, J. M.; Jonsson, H. H.; Welton, E. J.; Seinfield, J. H.

    2003-01-01

    We assess the consistency (closure) between solar beam attenuation by aerosols and water vapor measured by airborne sunphotometry and derived from airborne in-situ, and ship-based lidar measurements during the April 2001 Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia). The airborne data presented here were obtained aboard the Twin Otter aircraft. Comparing aerosol extinction o(550 nm) from four different techniques shows good agreement for the vertical distribution of aerosol layers. However, the level of agreement in absolute magnitude of the derived aerosol extinction varied among the aerosol layers sampled. The sigma(550 nm) computed from airborne in-situ size distribution and composition measurements shows good agreement with airborne sunphotometry in the marine boundary layer but is considerably lower in layers dominated by dust if the particles are assumed to be spherical. The sigma(550 nm) from airborne in-situ scattering and absorption measurements are about approx. 13% lower than those obtained from airborne sunphotometry during 14 vertical profiles. Combining lidar and the airborne sunphotometer measurements reveals the prevalence of dust layers at altitudes up to 10 km with layer aerosol optical depth (from 3.5 to 10 km altitude) of approx. 0.1 to 0.2 (500 nm) and extinction-to-backscatter ratios of 59-71 sr (523 nm). The airborne sunphotometer aboard the Twin Otter reveals a relatively dry atmosphere during ACE- Asia with all water vapor columns less than 1.5 cm and water vapor densities w less than 12 g/cu m. Comparing layer water vapor amounts and w from the airborne sunphotometer to the same quantities measured with aircraft in-situ sensors leads to a high correlation (r(sup 3)=0.96) but the sunphotometer tends to underestimate w by 7%.

  2. Effects of Relative Humidity on Ozone and Secondary Organic Aerosol Formation from the Photooxidation of Benzene and Ethylbenzene

    NASA Astrophysics Data System (ADS)

    Jia, L.; Xu, Y.

    2012-12-01

    The formation of ozone and secondary organic aerosol from benzene-NOx and ethylbenzene-NOx irradiations was investigated under different levels of relative humidity (RH) in a smog chamber. The results show that the increase in RH can greatly reduce the maximum O3 by the transformation of -NO2 and -ONO2-containing products into the particle phase. In benzene irradiations, the SOA number concentration increases over 26 times as RH rises from <5% to 80%, and the intensity of the bands of -OH, -C=O and C-OH from SOA samples also greatly increases with RH. In ethylbenzene irradiations, ethylglyoxal favors the formation of monohydrate, which limits the RH effects. During evaporating processes, the lost substances have similar structures for both benzene and ethylbenzene. This demonstrates that ethyl-containing substances are very stable and difficult to evaporate. For benzene some of glyoxal hydrates are left to form C-O-C and C=O-containing species like hemiacetal and acetal after evaporation, whereas for ethylbenzene, glyoxal favors cross reactions with ethylglyoxal during the evaporating process. It is concluded that the increase in RH can irreversibly enhance the yields of SOA from both benzene and ethylbenzene.

  3. Top-down estimates of benzene and toluene emissions in the Pearl River Delta and Hong Kong, China

    NASA Astrophysics Data System (ADS)

    Fang, Xuekun; Shao, Min; Stohl, Andreas; Zhang, Qiang; Zheng, Junyu; Guo, Hai; Wang, Chen; Wang, Ming; Ou, Jiamin; Thompson, Rona L.; Prinn, Ronald G.

    2016-03-01

    Benzene (C6H6) and toluene (C7H8) are toxic to humans and the environment. They are also important precursors of ground-level ozone and secondary organic aerosols and contribute substantially to severe air pollution in urban areas in China. Discrepancies exist between different bottom-up inventories for benzene and toluene emissions in the Pearl River Delta (PRD) and Hong Kong (HK), which are emission hot spots in China. This study provides top-down estimates of benzene and toluene emissions in the PRD and HK using atmospheric measurement data from a rural site in the area, Heshan, an atmospheric transport model, and an inverse modeling method. The model simulations captured the measured mixing ratios during most pollution episodes. For the PRD and HK, the benzene emissions estimated in this study for 2010 were 44 (12-75) and 5 (2-7) Gg yr-1 for the PRD and HK, respectively, and the toluene emissions were 131 (44-218) and 6 (2-9) Gg yr-1, respectively. Temporal and spatial differences between the inversion estimate and four different bottom-up emission estimates are discussed, and it is proposed that more observations at different sites are urgently needed to better constrain benzene and toluene (and other air pollutant) emissions in the PRD and HK in the future.

  4. Risk factors for injuries during airborne static line operations.

    PubMed

    Knapik, Joseph J; Steelman, Ryan

    2014-01-01

    US Army airborne operations began in World War II. Continuous improvements in parachute technology, aircraft exit procedures, and ground landing techniques have reduced the number of injuries over time from 27 per 1,000 descents to about 6 per 1,000 jumps. Studies have identified a number of factors that put parachutists at higher injury risk, including high wind speeds, night jumps, combat loads, higher temperatures, lower fitness, heavier body weight, and older age. Airborne injuries can be reduced by limiting risker training (higher wind speeds, night jumps, combat load) to the minimum necessary for tactical and operational proficiency. Wearing a parachute ankle brace (PAB) will reduce ankle injuries without increasing other injuries and should be considered by all parachutists, especially those with prior ankle problems. A high level of upper body muscular endurance and aerobic fitness is not only beneficial for general health but also associated with lower injury risk during airborne training.

  5. Risk factors for injuries during airborne static line operations.

    PubMed

    Knapik, Joseph J; Steelman, Ryan

    2014-01-01

    US Army airborne operations began in World War II. Continuous improvements in parachute technology, aircraft exit procedures, and ground landing techniques have reduced the number of injuries over time from 27 per 1,000 descents to about 6 per 1,000 jumps. Studies have identified a number of factors that put parachutists at higher injury risk, including high wind speeds, night jumps, combat loads, higher temperatures, lower fitness, heavier body weight, and older age. Airborne injuries can be reduced by limiting risker training (higher wind speeds, night jumps, combat load) to the minimum necessary for tactical and operational proficiency. Wearing a parachute ankle brace (PAB) will reduce ankle injuries without increasing other injuries and should be considered by all parachutists, especially those with prior ankle problems. A high level of upper body muscular endurance and aerobic fitness is not only beneficial for general health but also associated with lower injury risk during airborne training. PMID:25344715

  6. NASA Airborne Lidar 1982-1984 Flights

    Atmospheric Science Data Center

    2016-05-26

    NASA Airborne Lidar 1982-1984 Flights Data from the 1982 NASA Langley Airborne Lidar flights following the eruption of El Chichon ... continuing to January 1984. Transcribed from the following NASA Tech Reports: McCormick, M. P., and M. T. Osborn, Airborne lidar ...

  7. Laboratory Study of Airborne Fallout Particles and Their Time Distribution.

    ERIC Educational Resources Information Center

    Smith, H. A., Jr.; And Others

    1979-01-01

    Samples of filtered airborne particulate, collected daily for the first month after the September 18, 1977 Chinese nuclear detonation, showed fourteen fission products. Fluctuations in the daily fallout activity levels suggested a global fallout orbit time of approximately twenty days. (Author/BB)

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

    PubMed Central

    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 play a role in the in vivo myelotoxicity of benzene. Indeed, repeated coadministration of phenol and hydroquinone to B6C3F1 mice results in a dramatic and significant decrease in bone marrow cellularity similar to that observed following benzene exposure. A mechanism of benzene-induced myelotoxicity is therefore proposed in which the accumulation and interaction of phenol and hydroquinone in the bone marrow and the peroxidase-dependent formation of 1,4-benzoquinone are important components. This mechanism may also be responsible, at least in part, for benzene's genotoxic effects, as 1,4-benzoquinone has been shown to damage DNA and is shown here to induce multiple micronuclei in human lymphocytes. Secondary activation of benzene's phenol metabolites in the bone marrow may therefore play an important role in benzene's myelotoxic and carcinogenic effects. PMID:2551665

  9. Determination of airborne nanoparticles from welding operations.

    PubMed

    Gomes, João Fernando Pereira; Albuquerque, Paula Cristina Silva; Miranda, Rosa Maria Mendes; Vieira, Maria Teresa Freire

    2012-01-01

    The aim of this study is to assess the levels of airborne ultrafine particles emitted in welding processes (tungsten inert gas [TIG], metal active gas [MAG] of carbon steel, and friction stir welding [FSW] of aluminum) in terms of deposited area in pulmonary alveolar tract using a nanoparticle surface area monitor (NSAM) analyzer. The obtained results showed the dependence of process parameters on emitted ultrafine particles and demonstrated the presence of ultrafine particles compared to background levels. Data indicated that the process that resulted in the lowest levels of alveolar deposited surface area (ADSA) was FSW, followed by TIG and MAG. However, all tested processes resulted in significant concentrations of ultrafine particles being deposited in humans lungs of exposed workers.

  10. Determination of airborne nanoparticles from welding operations.

    PubMed

    Gomes, João Fernando Pereira; Albuquerque, Paula Cristina Silva; Miranda, Rosa Maria Mendes; Vieira, Maria Teresa Freire

    2012-01-01

    The aim of this study is to assess the levels of airborne ultrafine particles emitted in welding processes (tungsten inert gas [TIG], metal active gas [MAG] of carbon steel, and friction stir welding [FSW] of aluminum) in terms of deposited area in pulmonary alveolar tract using a nanoparticle surface area monitor (NSAM) analyzer. The obtained results showed the dependence of process parameters on emitted ultrafine particles and demonstrated the presence of ultrafine particles compared to background levels. Data indicated that the process that resulted in the lowest levels of alveolar deposited surface area (ADSA) was FSW, followed by TIG and MAG. However, all tested processes resulted in significant concentrations of ultrafine particles being deposited in humans lungs of exposed workers. PMID:22788362

  11. 40 CFR 80.1285 - How does a refiner apply for a benzene baseline?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 17 2014-07-01 2014-07-01 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...

  12. 40 CFR 80.1235 - What gasoline is subject to the benzene requirements of this subpart?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 17 2012-07-01 2012-07-01 false What gasoline is subject to the benzene requirements of this subpart? 80.1235 Section 80.1235 Protection of Environment ENVIRONMENTAL... Benzene Gasoline Benzene Requirements § 80.1235 What gasoline is subject to the benzene requirements...

  13. 40 CFR 80.1356 - What are the attest engagement requirements for gasoline benzene compliance?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

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

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 16 2011-07-01 2011-07-01 false What gasoline is subject to the benzene requirements of this subpart? 80.1235 Section 80.1235 Protection of Environment ENVIRONMENTAL... Benzene Gasoline Benzene Requirements § 80.1235 What gasoline is subject to the benzene requirements...

  15. 40 CFR 80.1356 - What are the attest engagement requirements for gasoline benzene compliance?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

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

  16. 40 CFR 80.1220 - What are the implementation dates for the gasoline benzene program?

    Code of Federal Regulations, 2010 CFR

    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...

  17. 40 CFR 80.1356 - What are the attest engagement requirements for gasoline benzene compliance?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

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

  18. 40 CFR 80.1235 - What gasoline is subject to the benzene requirements of this subpart?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false What gasoline is subject to the benzene requirements of this subpart? 80.1235 Section 80.1235 Protection of Environment ENVIRONMENTAL... Benzene Gasoline Benzene Requirements § 80.1235 What gasoline is subject to the benzene requirements...

  19. 40 CFR 80.1285 - How does a refiner apply for a benzene baseline?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 17 2013-07-01 2013-07-01 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...

  20. 40 CFR 80.1356 - What are the attest engagement requirements for gasoline benzene compliance?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

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

  1. 40 CFR 80.1285 - How does a refiner apply for a benzene baseline?

    Code of Federal Regulations, 2010 CFR

    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...

  2. 40 CFR 80.1220 - What are the implementation dates for the gasoline benzene program?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 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...

  3. 40 CFR 80.1235 - What gasoline is subject to the benzene requirements of this subpart?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 17 2013-07-01 2013-07-01 false What gasoline is subject to the benzene requirements of this subpart? 80.1235 Section 80.1235 Protection of Environment ENVIRONMENTAL... Benzene Gasoline Benzene Requirements § 80.1235 What gasoline is subject to the benzene requirements...

  4. 40 CFR 80.1285 - How does a refiner apply for a benzene baseline?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 17 2012-07-01 2012-07-01 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...

  5. 40 CFR 80.1285 - How does a refiner apply for a benzene baseline?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 16 2011-07-01 2011-07-01 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...

  6. 40 CFR 80.1220 - What are the implementation dates for the gasoline benzene program?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 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...

  7. 40 CFR 80.1220 - What are the implementation dates for the gasoline benzene program?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 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...

  8. 40 CFR 80.1356 - What are the attest engagement requirements for gasoline benzene compliance?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

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

  9. 40 CFR 80.1220 - What are the implementation dates for the gasoline benzene program?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 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...

  10. Airborne Imagery Collections Barrow 2013

    DOE Data Explorer

    Cherry, Jessica; Crowder, Kerri

    2015-07-20

    The data here are orthomosaics, digital surface models (DSMs), and individual frames captured during low altitude airborne flights in 2013 at the Barrow Environmental Observatory. The orthomosaics, thermal IR mosaics, and DSMs were generated from the individual frames using Structure from Motion techniques.

  11. Airborne fungi--a resurvey

    SciTech Connect

    Meyer, G.H.; Prince, H.E.; Raymer, W.J.

    1983-07-01

    A 15-month survey of airborne fungi at 14 geographical stations was conducted to determine the incidence of different fungal genera. Five of these stations were surveyed 25 years earlier. A comparison between previous studies and present surveys revealed similar organisms at each station with slight shifts in frequency of dominant genera.

  12. Tropospheric and Airborne Emission Spectrometers

    NASA Technical Reports Server (NTRS)

    Glavich, Thomas; Beer, Reinhard

    1996-01-01

    X This paper describes the development of two related instruments, the Tropospheric Emission Spectrometer (TES) and the Airborne Emission Spectrometer (AES). Both instruments are infrared imaging Fourier Transform Spectrometers, used for measuring the state of the lower atmosphere, and in particular the measurement of ozone and ozone sources and sinks.

  13. Airborne chemicals and forest health

    SciTech Connect

    Woodman, J.N.; Cowling, E.B.

    1987-02-01

    Over the past few years the possible contribution of acid rain to the problem of forest decline has been a cause of increasing public concern. Research has begun to determine whether airborne chemicals are causing or contributing to visible damage and mortality in eastern spruce-fir and sugar maple forests and to changes in tree growth, usually without visible symptoms, in other parts of North America. This paper describes some of the complex biological relationships that determine health and productivity of forests and that make it difficult to distinguish effects of airborne chemicals from effects of natural stress. It describes four major research approaches for assessment of the effects of airborne chemicals on forests, and it summarizes current understanding of the known and possible effects of airborne chemicals on forest trees in North America and Europe. It also briefly describes the major air quality and forest health research programs in North America, and it assesses how ell these programs are likely to meet information needs during the coming decade. 69 references, 2 figures, 1 table.

  14. Volatilization of benzene and eight alkyl-substituted benzene compounds from water

    USGS Publications Warehouse

    Rathbun, R.E.; Tai, D.Y.

    1988-01-01

    Predicting the fate of organic compounds in streams and rivers often requires knowledge of the volatilization characteristics of the compounds. The reference-substance concept, involving laboratory-determined ratios of the liquid-film coefficients for volatilization of the organic compounds to the liquid-film coefficient for oxygen absorption, is used to predict liquid-film coefficients for streams and rivers. In the absence of experimental data, two procedures have been used for estimating these liquid-film coefficient ratios. These procedures, based on the molecular-diffusion coefficient and on the molecular weight, have been widely used but never extensively evaluated. Liquid-film coefficients for the volatilization of benzene and eight alkyl-substituted benzene compounds (toluene through n-octylbenzene) from water were measured in a constant-temperature, stirred water bath. Liquid-film coefficients for oxygen absorption were measured simultaneously. A range of water mixing conditions was used with a water temperature of 298.2 K. The ratios of the liquid-film coefficients for volatilization to the liquid-film coefficient for oxygen absorption for all of the organic compounds were independent of mixing conditions in the water. Experimental ratios ranged from 0.606 for benzene to 0.357 for n-octylbenzene. The molecular-diffusion-coefficient procedure accurately predicted the ratios for ethylbenzene through n-pentylbenzene with a power dependence of 0.566 on the molecular-diffusion coefficient, in agreement with published values. Predicted ratios for benzene and toluene were slightly larger than the experimental ratios. These differences were attributed to possible interactions between the molecules of these compounds and the water molecules and to benzene-benzene interactions that form dimers. Because these interactions also are likely to occur in natural waters, it was concluded that the experimental ratios are more correct than the predicted ratios for

  15. Transfer of electronic energy from cyclohexane to benzene to tetramethylphenylenediamine

    SciTech Connect

    Johnston, D.B.; Lipsky, S. )

    1991-03-07

    The absorption of 160-nm light by cyclohexane in mixtures of cyclohexane, benzene, and tetraphenylmethylenediamine results in an emission spectrum consisting of the simultaneous fluorescence from all three components. A mechanism for the development of this spectrum and its dependence on benzene concentration is constructed and shown to be quantitatively consistent with the results of independent measurements on the separate components. In the absence of tetraphenylmethylenediamine, the quenching of cyclohexane fluorescence by benzene is found to be well represented by the standard diffusion model but with important contributions from transient terms. However, the concomitant sensitization of benzene fluorescence via energy transfer from cyclohexane is found to occur with an efficiency factor of only 0.26 {plus minus} 0.02 per encounter.

  16. Chemisorption of benzene and STM dehydrogenation products on Cu(100)

    NASA Astrophysics Data System (ADS)

    Lorente, N.; Hedouin, M. F.; Palmer, R. E.; Persson, M.

    2003-10-01

    Modification of individual chemisorbed benzene molecules on Cu(100) has recently been performed in atomic manipulation experiments [J. Phys. Chem. A. 104, 2463 (2000); Surf. Sci 451, 219 (2000)]. Benzene dissociates under controlled voltage pulses in a scanning tunneling microscope (STM) junction. The reaction is characterized as a dehydrogenation process and the fragments are identified as benzyne, C6H4. Here we present a density functional theory investigation of the chemisorption of benzene on the Cu(100) surface, the nature of the bonding and its effect on the STM images. The fragments phenyl and benzyne formed after one-fold and two-fold dehydrogenation of chemisorbed benzene are studied in the same manner. The stability of the fragments is explored via their chemisorption energy, their electronic structure on the surface and their affinity for hydrogen. Benzyne fragments seem to be the most stable, in agreement with the conclusion of the aforementioned STM experiments.

  17. Benzene removal by PAC in jet flocculation system

    SciTech Connect

    Sobrinho, J.A.H.; Thiem, L.T.; Alkhatib, E.A.

    1997-10-01

    A jet flocculator/powdered activated carbon (PAC) adsorption pilot plant was designed, built, and operated in order to evaluate a water treatment process capable of simultaneous adsorption of benzene and flocculation of PAC and silica clay particles. The jet flocculation/PAC system successfully combined, in the same reactor, flocculation of suspended solids by using jet mixing, solids retention using pall rings, and benzene removal by PAC adsorption. The advantages of this process included operational simplicity, reliability, and low energy consumption. The jet flocculator/PAC adsorption system was able to achieve suspended solids and benzene removals of approximately 80 and 95%, respectively, from an influent containing 70 mg/L of suspended solids (silica clay and PAC) and 100 {micro}g/L of benzene.

  18. Which ornamental plant species effectively remove benzene from indoor air?

    NASA Astrophysics Data System (ADS)

    Liu, Yan-Ju; Mu, Yu-Jing; Zhu, Yong-Guan; Ding, Hui; Crystal Arens, Nan

    Phytoremediation—using plants to remove toxins—is an attractive and cost effective way to improve indoor air quality. This study screened ornamental plants for their ability to remove volatile organic compounds from air by fumigating 73 plant species with 150 ppb benzene, an important indoor air pollutant that poses a risk to human health. The 10 species found to be most effective at removing benzene from air were fumigated for two more days (8 h per day) to quantify their benzene removal capacity. Crassula portulacea, Hydrangea macrophylla, Cymbidium Golden Elf., Ficus microcarpa var. fuyuensis, Dendranthema morifolium, Citrus medica var. sarcodactylis, Dieffenbachia amoena cv. Tropic Snow; Spathiphyllum Supreme; Nephrolepis exaltata cv. Bostoniensis; Dracaena deremensis cv. Variegata emerged as the species with the greatest capacity to remove benzene from indoor air.

  19. A PROBABILISTIC MODELING FRAMEWORK FOR PREDICTING POPULATION EXPOSURES TO BENZENE

    EPA Science Inventory

    The US Environmental Protection Agency (EPA) is modifying their probabilistic Stochastic Human Exposure Dose Simulation (SHEDS) model to assess aggregate exposures to air toxics. Air toxics include urban Hazardous Air Pollutants (HAPS) such as benzene from mobile sources, part...

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

    SciTech Connect

    Weinelt, M.; Nilsson, A.; Wassdahl, N.

    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.