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Sample records for tetrachloroethylene toluene trichloroethylene

  1. Transformation of tetrachloroethylene to trichloroethylene by homoacetogenic bacteria.

    PubMed

    Terzenbach, D P; Blaut, M

    1994-10-15

    Eight homoacetogenic strains of the genera Acetobacterium, Clostridium and Sporomusa were tested for their ability to dechlorinate tetrachloroethylene (perchloroethene, PCE). Of the organisms tested only Sporomusa ovata was able to reductively dechlorinate PCE with methanol as an electron donor. Resting cells of S. ovata reductively dechlorinated PCE at a rate of 9.8 nmol h-1 (mg protein)-1 to trichloroethylene (TCE) as the sole product. The dechlorination activity depended on concomitant acetogenesis from methanol and CO2. Cell-free extracts of S. ovata, Clostridium formicoaceticum, Acetobacterium woodii, and the methanogenic bacterium Methanolobus tindarius transformed PCE to TCE with Ti(III) or carbon monoxide as electron donors. Corrinoids were shown in S. ovata to be involved in the dechlorination reaction of PCE to TCE as evident from the reversible inhibition with propyl iodide. Rates of dechlorination followed a pseudo-first-order kinetic. PMID:7988892

  2. Degradation of trichloroethylene by toluene dioxygenase in whole-cell studies with Pseudomonas putida F1.

    PubMed Central

    Wackett, L P; Gibson, D T

    1988-01-01

    Toluene-induced cells of Pseudomonas putida F1 removed trichloroethylene from growth media at a significantly greater initial rate than the methanotroph Methylosinus trichosporium OB3b. With toluene-induced P. putida F1, the initial degradation rate varied linearly with trichloroethylene concentration over the range of 8 to 80 microM (1.05 to 10.5 ppm). At 80 microM (10.5 ppm) trichloroethylene and 30 degrees C, the initial rate was 1.8 nmol/min per mg of total cell protein, but the rate decreased rapidly with time. A series of mutant strains derived from P. putida F1 that are defective in the todC gene, which encodes the oxygenase component of toluene dioxygenase, failed to degrade trichloroethylene and to oxidize indole to indigo. A spontaneous revertant selected from a todC culture regained simultaneously the abilities to oxidize toluene, to form indigo, and to degrade trichloroethylene. The three isomeric dichloroethylenes were degraded by P. putida F1, but tetrachloroethylene, vinyl chloride, and ethylene were not removed from incubation mixtures. PMID:3415234

  3. Tetrachloroethylene

    Integrated Risk Information System (IRIS)

    Tetrachloroethylene ( Perchloroethylene ) ; CASRN 127 - 18 - 4 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessm

  4. Use of Mini-Sprinklers to Strip Trichloroethylene and Tetrachloroethylene from Contaminated Ground Water.

    SciTech Connect

    Brerisford, Yvette, C.; Bush, Parshall, B.; Blake, John, I.; Bayer, Cassandra L.

    2003-01-01

    Berisford, Y.C., P.B. Bush, J.I. Blake, and C.L. Bayer. 2003. Use of mini-sprinklers to strip trichloroethylene and tetrachloroethylene from contaminated ground water. J. Env. Qual. 32:801-815. Three low-volume mini-sprinklers were tested for their efficacy to strip trichloroethylene (TCE) and tetrachloroethylene (PCE) from water. Deionized water spiked with TCE and PCE was pumped through a mini-sprinkler supported on top of a 1.8-m-tall. Water was collected in collection vessels at 0.61 and 1.22 m above the ground on support columns that were spaced at 0.61-m intervals from the riser base, and samples were composited per height and distance from the riser. Overall, air-stripping reduced dissolved concentrations of TCE and PCE by 99.1 to 100 and 96.9 to 100%, respectively. Mini-sprinklers offer the advantages of (i) easy setup in series that can be used on practically any terrain; (ii) operation over a long period of time that does not threaten aquifer depletion; (iii) use in small or confined aquifers in which the capacity is too low to support large irrigation or pumping systems; and (iv) use in forests in which the small, low-impact droplets of the mini-sprinklers do not damage bark and in which trees can help manage (via evapotransporation) excess waste water.

  5. Kinetics of the transformation of trichloroethylene and tetrachloroethylene by iron sulfide

    SciTech Connect

    Butler, E.C.; Hayes, K.F. . Dept. of Civil and Environmental Engineering)

    1999-06-15

    The transformation of trichloroethylene (TCE), tetrachloroethylene (PCE), and 1,1-dichloroethylene FeS in aqueous solution at pH 8.3 was studied in batch experiments. TCE and PCE were transformed by FeS with pseudo-first-order rate constants, corrected for partitioning to the sample headspace, of (1.49 [+-] 0.14) [times] 10[sup [minus]3] h[sup [minus]1] (TCE) and (5.7 [+-] 1.0) [times] 10[sup [minus]4] h[sup [minus]1] (PCE). A 17% decrease in the concentration of 1,3-DCE was observed over 120 days; however, no reaction products were detected. TCE and PCE transformation data were fit to a rate law assuming transformation of TCE via parallel reaction pathways to acetylene and cis-1,2-dichloroethylene (cis-DCE) and transformation of PCE via parallel reaction pathways to acetylene and TCE. Acetylene was the major reaction product for both TCE and PCE. Determination of rate constants for each reaction pathway indicated that TCE was transformed to acetylene 11.8 [+-] 1.1 times faster than to cis-DCE and that PCE was transformed to acetylene 8.2 [+-] 1.8 times faster than to TCE. Additional minor reaction products were vinyl chloride (VC) for TCE and cis-DCE for PCE. Detection of acetylene as the major product of both TCE and PCE transformation by FeS contrasts with the sequential hydrogenolysis products typically observed in the microbial transformation of these compounds, making acetylene a potential indicator of abiotic transformation of TCE and PCE by FeS in natural systems.

  6. Mutagenicity of the Cysteine S-Conjugate Sulfoxides of Trichloroethylene and Tetrachloroethylene in the Ames Test

    PubMed Central

    Irving, Roy M.; Elfarra, Adnan A.

    2013-01-01

    The nephrotoxicity and nephrocarcinogenicity of trichloroethylene (TCE) and tetrachloroethylene (PCE) are believed to be mediated primarily through the cysteine S-conjugate β-lyase-dependent bioactivation of the corresponding cysteine S-conjugate metabolites S-(1,2-dichlorovinyl)-L-cysteine (DCVC) and S-(1,2,2-trichlorovinyl)-L-cysteine (TCVC), respectively. DCVC and TCVC have previously been demonstrated to be mutagenic by the Ames Salmonella mutagenicity assay, and reduction in mutagenicity was observed upon treatment with the β-lyase inhibitor aminooxyacetic acid (AOAA). Because DCVC and TCVC can also be bioactivated through sulfoxidation to yield the potent nephrotoxicants S-(1,2-dichlorovinyl)-L-cysteine sulfoxide (DCVCS) and S-(1,2,2-trichlorovinyl)-L-cysteine sulfoxide (TCVCS), respectively, the mutagenic potential of these two sulfoxides was investigated using the Ames S. typhimuriumTA100 mutagenicity assay. The results show both DCVCS and TCVCS were mutagenic, and TCVCS exhibited 3-fold higher mutagenicity than DCVCS. However, DCVCS and TCVCS mutagenic activity was approximately 700-fold and 30-fold lower than DCVC and TCVC, respectively. DCVC and DCVCS appeared to induce toxicity in TA100, as evidenced by increased microcolony formation and decreased mutant frequency above threshold concentrations. TCVC and TCVCS were not toxic in TA100. The toxic effects of DCVC limited the sensitivity of TA100 to DCVC mutagenic effects and rendered it difficult to investigate the effects of AOAA on DCVC mutagenic activity. Collectively, these results suggest that DCVCS and TCVCS exerted a definite but weak mutagenicity in the TA100 strain. Therefore, despite their potent nephrotoxicity, DCVCS and TCVCS are not likely to play a major role in DCVC or TCVC mutagenicity in this strain. PMID:23416178

  7. Effect of trichloroethylene and tetrachloroethylene on methane oxidation and community structure of methanotrophic consortium.

    PubMed

    Choi, Sun-Ah; Lee, Eun-Hee; Cho, Kyung-Suk

    2013-01-01

    The methane oxidation rate and community structure of a methanotrophic consortium were analyzed to determine the effects of trichloroethylene (TCE) and tetrachloroethylene (PCE) on methane oxidation. The maximum methane oxidation rate (Vmax ) of the consortium was 326.8 μmol·g-dry biomass(-1)·h(-1), and it had a half-saturation constant (Km ) of 143.8 μM. The addition of TCE or PCE resulted in decreased methane oxidation rates, which were decreased from 101.73 to 5.47-24.64 μmol·g-dry biomass(-1)·h(-1) with an increase in the TCE-to-methane ratio, and to 61.95-67.43 μmol·g-dry biomass(-1)·h(-1) with an increase in the PCE-to-methane ratio. TCE and PCE were non-competitive inhibitors for methane oxidation, and their inhibition constants (Ki ) were 33.4 and 132.0 μM, respectively. When the methanotrophic community was analyzed based on pmoA using quantitative real-time PCR (qRT-PCR), the pmoA gene copy numbers were shown to decrease from 7.3 ± 0.7 × 10(8) to 2.1-5.0 × 10(7) pmoA gene copy number · g-dry biomass(-1) with an increase in the TCE-to-methane ratio and to 2.5-7.0 × 10(7) pmoA gene copy number · g-dry biomass(-1) with an increase in the PCE-to-methane ratio. Community analysis by microarray demonstrated that Methylocystis (type II methanotrophs) were the most abundant in the methanotrophic community composition in the presence of TCE. These results suggest that toxic effects caused by TCE and PCE change not only methane oxidation rates but also the community structure of the methanotrophic consortium. PMID:23947712

  8. Kinetic study of trichloroethylene and toluene degradation by a bioluminescent reporter bacterium

    SciTech Connect

    Kelly, C.J.; Sanseverino, J.; Bienkowski, P.R.; Sayler, G.S.

    1995-12-31

    A constructed bioluminescent reporter bacterium, Pseudomonas putida B2, is very briefly described in this paper. The bacterium degrades toluene and trichloroethylene (TCE), and produces light in the presence of toluene. The light response is an indication of cellular viability and expression of the genes encoding toluene and TCE degrading enzymes.

  9. Trichloroethylene oxidation by purified toluene 2-monooxygenase: products, kinetics, and turnover-dependent inactivation.

    PubMed Central

    Newman, L M; Wackett, L P

    1997-01-01

    Trichloroethylene is oxidized by several types of nonspecific bacterial oxygenases. Toluene 2-monooxygenase from Burkholderia cepacia G4 is implicated in trichloroethylene oxidation and is uniquely suggested to be resistant to turnover-dependent inactivation in vivo. In this work, the oxidation of trichloroethylene was studied with purified toluene 2-monooxygenase. All three purified toluene 2-monooxygenase protein components and NADH were required to reconstitute full trichloroethylene oxidation activity in vitro. The apparent Km and Vmax were 12 microM and 37 nmol per min per mg of hydroxylase component, respectively. Ten percent of the full activity was obtained when the small-molecular-weight enzyme component was omitted. The stable oxidation products, accounting for 84% of the trichloroethylene oxidized, were carbon monoxide, formic acid, glyoxylic acid, and covalently modified oxygenase proteins that constituted 12% of the reacted [14C]trichloroethylene. The stable oxidation products may all derive from the unstable intermediate trichloroethylene epoxide that was trapped by reaction with 4-(p-nitrobenzyl)pyridine. Chloral hydrate and dichloroacetic acid were not detected. This finding differs from that with soluble methane monooxygenase and cytochrome P-450 monooxygenase, which produce chloral hydrate. Trichloroethylene-dependent inactivation of toluene 2-monooxygenase activity was observed. All of the protein components were covalently modified during the oxidation of trichloroethylene. The addition of cysteine to reaction mixtures partially protected the enzyme system against inactivation, most notably protecting the NADH-oxidoreductase component. This suggested the participation of diffusible intermediates in the inactivation of the oxidoreductase. PMID:8981984

  10. Trichloroethylene degradation by Escherichia coli containing the cloned Pseudomonas putida F1 toluene dioxygenase genes

    SciTech Connect

    Zylstra, G.J.; Gibson, D.T. ); Wackett, L.P. )

    1989-12-01

    Toluene dioxygenase from Pseudomonas putida F1 has been implicated as an enzyme capable of degrading trichloroethylene. This has now been confirmed with Escherichia coli JM109(pDTG601) that contains the structural genes (todC1C2BA) of toluene dioxygenase under the control of the tac promoter. The extent of trichloroethylene degradation by the recombinant organism depended on the cell concentration and the concentration of trichloroethylene. A linear rate of trichloroethylene degradation was observed with the E. coli recombinant strain. In contrast, P. putida F39/D, a mutant strain of P. putida F1 that does not contain cis-toluene dihydrodiol dehydrogenase, showed a much faster initial rate of trichloroethylene degradation which decreased over time.

  11. Novel Pathway of Toluene Catabolism in the Trichloroethylene-Degrading Bacterium G4

    PubMed Central

    Shields, Malcolm S.; Montgomery, Stacy O.; Chapman, Peter J.; Cuskey, Stephen M.; Pritchard, P. H.

    1989-01-01

    o-Cresol and 3-methylcatechol were identified as successive transitory intermediates of toluene catabolism by the trichloroethylene-degrading bacterium G4. The absence of a toluene dihydrodiol intermediate or toluene dioxygenase and toluene dihydrodiol dehydrogenase activities suggested that G4 catabolizes toluene by a unique pathway. Formation of a hybrid species of 18O- and 16O-labeled 3-methylcatechol from toluene in an atmosphere of 18O2 and 16O2 established that G4 catabolizes toluene by successive monooxygenations at the ortho and meta positions. Detection of trace amounts of 4-methylcatechol from toluene catabolism suggested that the initial hydroxylation of toluene was not exclusively at the ortho position. Further catabolism of 3-methylcatechol was found to proceed via catechol-2,3-dioxygenase and hydroxymuconic semialdehyde hydrolase activities. PMID:16347956

  12. Recruitment and expression of toluene/trichloroethylene biodegradation genes in bacteria native to deep-subsurface sediments.

    PubMed Central

    Romine, M F; Brockman, F J

    1996-01-01

    Four plasmids, each encoding a combination of either an Escherichia coli or Pseudomonas putida promoter and either toluene dioxygenase or toluene monooxygenase, were electroporated into five bacterial strains isolated from sediments found at depths of 91 to 295 m. Four of these engineered bacterial strains demonstrated both toluene and trichloroethylene degradation activities. PMID:8779603

  13. Recruitment and expression of toluene/trichloroethylene biodegradation genes in bacteria native to deep-subsurface sediments

    SciTech Connect

    Romine, M.F.; Brockman, F.J.

    1996-07-01

    Four plasmids, each encoding a combination of either an Escherichia coli or Pseudomonas putida promoter and either toluene dioxygenase or toluene monooxygenase, were electroporated into five bacterial strains isolated from sediments found at depths of 91 to 295 m. Four of these engineered bacterial strains demonstrated both toluene and trichloroethylene degradation activities. 26 refs., 2 tabs.

  14. Adverse Birth Outcomes and Maternal Exposure to Trichloroethylene and Tetrachloroethylene through Soil Vapor Intrusion in New York State

    PubMed Central

    Lewis-Michl, Elizabeth L.; Gomez, Marta I.

    2011-01-01

    Background: Industrial spills of volatile organic compounds (VOCs) in Endicott, New York (USA), have led to contamination of groundwater, soil, and soil gas. Previous studies have reported an increase in adverse birth outcomes among women exposed to VOCs in drinking water. Objective: We investigated the prevalence of adverse birth outcomes among mothers exposed to trichloroethylene (TCE) and tetrachloroethylene [or perchloroethylene (PCE)] in indoor air contaminated through soil vapor intrusion. Methods: We examined low birth weight (LBW), preterm birth, fetal growth restriction, and birth defects among births to women in Endicott who were exposed to VOCs, compared with births statewide. We used Poisson regression to analyze births and malformations to estimate the association between maternal exposure to VOCs adjusting for sex, mother’s age, race, education, parity, and prenatal care. Two exposure areas were identified based on environmental sampling data: one area was primarily contaminated with TCE, and the other with PCE. Results: In the TCE-contaminated area, adjusted rate ratios (RRs) were significantly elevated for LBW [RR = 1.36; 95% confidence interval (CI): 1.07, 1.73; n = 76], small for gestational age (RR = 1.23; 95% CI: 1.03, 1.48; n = 117), term LBW (RR = 1.68; 95% CI: 1.20, 2.34; n = 37), cardiac defects (RR = 2.15; 95% CI: 1.27, 3.62; n = 15), and conotruncal defects (RR = 4.91; 95% CI: 1.58, 15.24; n = 3). In the PCE-contaminated area, RRs for cardiac defects (five births) were elevated but not significantly. Residual socioeconomic confounding may have contributed to elevations of LBW outcomes. Conclusions: Maternal residence in both areas was associated with cardiac defects. Residence in the TCE area, but not the PCE area, was associated with LBW and fetal growth restriction. PMID:22142966

  15. Effect of trichloroethylene (TCE) and toluene concentrations on TCE and toluene biodegradation and the population density of TCE and toluene degraders in soil

    SciTech Connect

    Mu, D.Y.; Scow, K.M.

    1994-07-01

    Toluene is one of several cosubstrates able to support the cometabolism of trichloroethylene (TCE) by soil microbial communities. Indigenous microbial populations in soil degraded TCE in the presence, but not the absence, of toluene after a 60- to 80-h lag period. Initial populations of toluene and TCE degraders ranged from 0.2 x 10{sup 3} to 4 x 10{sup 3} cells per g of soil and increased by more than 4 orders of magnitude after the addition of 20 {mu}g of toluene and 1 {mu}g of TCE per mol of soil solution. The numbers of TCE and toluene degraders and the percent removal of TCE increased with an increase in initial toluene concentration. As the initial TCE concentration was increased from 1 to 20 {mu}g/ml, the numbers of toluene and TCE degraders and the rate of toluene degradation decreased, and no TCE degradation occurred. No toluene or TCE degradation occurred at a TCE concentration of 50 {mu}g/ml. 22 refs., 3 figs., 2 tabs.

  16. Kinetics of trichloroethylene cometabolism and toluene biodegradation: Model application to soil batch experiments

    SciTech Connect

    El-Farhan, Y.H.; Scow, K.M.; Fan, S.; Rolston, D.E.

    2000-06-01

    Trichloroethylene (TCE) biodegradation in soil under aerobic conditions requires the presence of another compound, such as toluene, to support growth of microbial populations and enzyme induction. The biodegradation kinetics of TCE and toluene were examined by conducting three groups of experiments in soil: toluene only, toluene combined with low TCE concentrations, and toluene with TCE concentrations similar to or higher than toluene. The biodegradation of TCE and toluene and their interrelationships were modeled using a combination of several biodegradation functions. In the model, the pollutants were described as existing in the solid, liquid, and gas phases of soil, with biodegradation occurring only in the liquid phase. The distribution of the chemicals between the solid and liquid phase was described by a linear sorption isotherm, whereas liquid-vapor partitioning was described by Henry's law. Results from 12 experiments with toluene only could be described by a single set of kinetic parameters. The same set of parameters could describe toluene degradation in 10 experiments where low TCE concentrations were present. From these 10 experiments a set of parameters describing TCE cometabolism induced by toluene also was obtained. The complete set of parameters was used to describe the biodegradation of both compounds in 15 additional experiments, where significant TCE toxicity and inhibition effects were expected. Toluene parameters were similar to values reported for pure culture systems. Parameters describing the interaction of TCE with toluene and biomass were different from reported values for pure cultures, suggesting that the presence of soil may have affected the cometabolic ability of the indigenous soil microbial populations.

  17. Trichloroethylene removal and oxidation toxicity mediated by toluene dioxygenase of Pseudomonas putida

    SciTech Connect

    Heald, S.; Jenkins, R.O.

    1994-12-01

    Trichloroethylene (TCE) is a major ground water contaminant and potential health hazard in drinking water. This paper reports on the cometabolism of TCE by a wild-type strain of Pseudomonas putida containing an inducible toluene dioxygenase enzyme. The results show rapid TCE removal by the strain but severe oxidation toxicity and rapid cell death. This is also the first report of enhanced capacity of bacterial cells to remove TCE in the presence of dithiothreitol. Presented also is evidence for induction of toluene degradation by TCE. 17 refs., 2 figs., 2 tabs.

  18. Transfer of methyl chloroform, trichloroethylene and tetrachloroethylene to milk, tissues and expired air following intraruminal or oral administration in lactating goats and milk-fed kids.

    PubMed

    Hamada, T; Tanaka, H

    1995-01-01

    The distribution of methyl chloroform was determined (MCF), trichloroethylene (TRI) and tetrachloroethylene (PCE) in milk, tissues and expired air by intraruminally administering 0.625 ml kg(-0.75) of an equal-volume mixture of the three compounds to lactating goats. The milk secreted during 24 h after the intraruminal administration contained 1.42 mg of MCF, 1.87 mg of TRI, 6.43 mg of PCE and 0.33 mg of trichloroethanol (TCE). MCF, TRI and PCE appeared in the blood less than 30 min after administration. Oral administration of these chemicals to milk-fed kids showed that at 3.5 h post-administration, the liver contained these chemicals in greatest abundance. The adaptation of milk-fed kids to 3 weeks administration of small amounts of propylene glycol stimulated the metabolic conversion of TRI to TCE. There were linear relationships between the blood concentrations of these chemicals and the expiration rates after oral administration of 0.4 ml kg(-1) of each chemical to milk-fed kids. The expiration rates of MCF, TRI and PCE were 605, 122 and 46 microg min(-1) kg(-1) at 2 microg ml(-1) blood concentrations of MCF, TRI and PCE, respectively. These results suggested that MCF is little metabolized, being most readily exhaled in expired air, while PCE demonstrates the greatest tissue-partitioning, being largely secreted into the milk or retained in the liver. TRI can be extensively metabolized to other compounds such as TCE in milk-fed kids. PMID:15091581

  19. Oxidation of trichloroethylene, toluene, and ethanol vapors by a partially saturated permeable reactive barrier

    NASA Astrophysics Data System (ADS)

    Mahmoodlu, Mojtaba G.; Hassanizadeh, S. Majid; Hartog, Niels; Raoof, Amir

    2014-08-01

    The mitigation of volatile organic compound (VOC) vapors in the unsaturated zone largely relies on the active removal of vapor by ventilation. In this study we considered an alternative method involving the use of solid potassium permanganate to create a horizontal permeable reactive barrier for oxidizing VOC vapors. Column experiments were carried out to investigate the oxidation of trichloroethylene (TCE), toluene, and ethanol vapors using a partially saturated mixture of potassium permanganate and sand grains. Results showed a significant removal of VOC vapors due to the oxidation. We found that water saturation has a major effect on the removal capacity of the permeable reactive layer. We observed a high removal efficiency and reactivity of potassium permanganate for all target compounds at the highest water saturation (Sw = 0.6). A change in pH within the reactive layer reduced oxidation rate of VOCs. The use of carbonate minerals increased the reactivity of potassium permanganate during the oxidation of TCE vapor by buffering the pH. Reactive transport of VOC vapors diffusing through the permeable reactive layer was modeled, including the pH effect on the oxidation rates. The model accurately described the observed breakthrough curve of TCE and toluene vapors in the headspace of the column. However, miscibility of ethanol in water in combination with produced water during oxidation made the modeling results less accurate for ethanol. A linear relationship was found between total oxidized mass of VOC vapors per unit volume of permeable reactive layer and initial water saturation. This behavior indicates that pH changes control the overall reactivity and longevity of the permeable reactive layer during oxidation of VOCs. The results suggest that field application of a horizontal permeable reactive barrier can be a viable technology against upward migration of VOC vapors through the unsaturated zone.

  20. Trichloroethylene

    Integrated Risk Information System (IRIS)

    Trichloroethylene ; CASRN 79 - 01 - 6 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic

  1. Oxidation of trichloroethylene, 1,1-dichloroethylene, and chloroform by toluene/o-xylene monooxygenase from Pseudomonas stutzeri OX1

    SciTech Connect

    Chauhan, S.; Wood, T.K.; Barbieri, P.

    1998-08-01

    Toluene/o-xylene monooxygenase (ToMO) from Pseudomonas stutzeri OX1, which oxidizes toluene and o-xylene, was examined for its ability to degrade the environmental pollutants trichloroethylene (TCE), 1,1-dichloroethylene (1,1-DCE), cis-1,2-DCE, trans-1,2-DCE, chloroform, dichloromethane, phenol, 2,4-dichlorophenol, 2,4,5-trichlorophenol, 2,4,6-trichlorophenol, 2,3,5,6-tetrachlorophenol, and 2,3,4,5,6-pentachlorophenol. Escherichia coli JM109 that expressed ToMO from genes on plasmid pBZ1260 under control of the lac promoter degraded TCE, 1,1-DCE, and chloroform at initial rates of 3.1, 3.6, and 1.6 nmol, respectively. Stoichiometric amounts of chloride release were seen, indicating mineralization. Thus, the substrate range of ToMO is extended to include aliphatic chlorinated compounds.

  2. Cometabolic degradation of trichloroethylene by Pseudomonas cepacia G4 in a chemostat with toluene as the primary substrate.

    PubMed Central

    Landa, A S; Sipkema, E M; Weijma, J; Beenackers, A A; Dolfing, J; Janssen, D B

    1994-01-01

    Pseudomonas cepacia G4 is capable of cometabolic degradation of trichloroethylene (TCE) if the organism is grown on certain aromatic compounds. To obtain more insight into the kinetics of TCE degradation and the effect of TCE transformation products, we have investigated the simultaneous conversion of toluene and TCE in steady-state continuous culture. The organism was grown in a chemostat with toluene as the carbon and energy source at a range of volumetric TCE loading rates, up to 330 mumol/liter/h. The specific TCE degradation activity of the cells and the volumetric activity increased, but the efficiency of TCE conversion dropped when the TCE loading was elevated from 7 to 330 mumol/liter/h. At TCE loading rates of up to 145 mumol/liter/h, the specific toluene conversion rate and the molar growth yield of the cells were not affected by the presence of TCE. The response of the system to varying TCE loading rates was accurately described by a mathematical model based on Michaelis-Menten kinetics and competitive inhibition. A high load of 3,400 mumol of TCE per liter per h for 12 h caused inhibition of toluene and TCE conversion, but reduction of the TCE load to the original nontoxic level resulted in complete recovery of the system within 2 days. These results show that P. cepacia can stably and continuously degrade toluene and TCE simultaneously in a single-reactor system without biomass retention and that the organism is more resistant to high concentrations and shock loadings of TCE than Methylosinus trichosporium OB3b. PMID:7524444

  3. Modeling trichloroethylene degradation by a recombinant pseudomonad expressing toluene ortho-monooxygenase in a fixed-film bioreactor

    SciTech Connect

    Sun, A.K.; Hong, J.; Wood, T.K.

    1998-07-05

    Burkholderia cepacia PR1{sub 23}(TOM{sub 23C}), expressing constitutively the TCE-degrading enzyme toluene ortho-monooxygenase (Tom), was immobilized on SIRAN{trademark} glass beads in a biofilter for the degradation and mineralization of gas-phase trichloroethylene (TCE). To interpret the experimental results, a mathematical model has been developed which includes axial dispersion, convection, film mass-transfer, and biodegradation coupled with deactivation of the TCE-degrading enzyme. Parameters used for numerical simulation were determined from either independent experiments or values reported in the literature. The model was compared with the experimental data, and there was good agreement between the predicted and measured TCE breakthrough curves. The simulations indicated that TCE degradation in the biofilter was not limited by mass transfer of TCE or oxygen from the gas phase to the liquid/biofilm phase (biodegradation limits), and predicts that improving the specific TCE degradation rates of bacteria will not significantly enhance long-term biofilter performance. The most important factors for prolonging the performance of biofilter are increasing the amount of active biomass and the transformation capacity enhancing resistance to TCE metabolism.

  4. Rhizoremediation of Trichloroethylene by a Recombinant, Root-Colonizing Pseudomonas fluorescens Strain Expressing Toluene ortho-Monooxygenase Constitutively

    PubMed Central

    Yee, Dennis C.; Maynard, Jennifer A.; Wood, Thomas K.

    1998-01-01

    Trichloroethylene (TCE) was removed from soils by using a wheat rhizosphere established by coating seeds with a recombinant, TCE-degrading Pseudomonas fluorescens strain that expresses the tomA+ (toluene o-monooxygenase) genes from Burkholderia cepacia PR123(TOM23C). A transposon integration vector was used to insert tomA+ into the chromosome of P. fluorescens 2-79, producing a stable strain that expressed constitutively the monooxygenase at a level of 1.1 nmol/min · mg of protein (initial TCE concentration, 10 μM, assuming that all of the TCE was in the liquid) for more than 280 cell generations (36 days). We also constructed a salicylate-inducible P. fluorescens strain that degraded TCE at an initial rate of 2.6 nmol/min · mg of protein in the presence of 10 μM TCE [cf. B. cepacia G4 PR123(TOM23C), which degraded TCE at an initial rate of 2.5 nmol/min · mg of protein]. A constitutive strain, P. fluorescens 2-79TOM, grew (maximum specific growth rate, 0.78 h−1) and colonized wheat (3 × 106 CFU/cm of root) as well as wild-type P. fluorescens 2-79 (maximum specific growth rate, 0.77 h−1; level of colonization, 4 × 106 CFU/cm of root). Rhizoremediation of TCE was demonstrated by using microcosms containing the constitutive monooxygenase-expressing microorganism, soil, and wheat. These closed microcosms degraded an average of 63% of the initial TCE in 4 days (20.6 nmol of TCE/day · plant), compared to the 9% of the initial TCE removed by negative controls consisting of microcosms containing wild-type P. fluorescens 2-79-inoculated wheat, uninoculated wheat, or sterile soil. PMID:9435067

  5. Toluene

    Integrated Risk Information System (IRIS)

    Toluene ; CASRN 108 - 88 - 3 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Effects )

  6. TRICHLOROETHYLENE METABOLISM BY MICROORGANISMS THAT DEGRADE AROMATIC COMPOUNDS

    EPA Science Inventory

    Trichloroethylene (TCE) was metabolized by the natural microflora of three different environmental water samples when stimulated by the addition of either toluene or phenol. Two different strains of Pseudomonas putida that degrade toluene by a pathway containing a toluene dioxyge...

  7. TRICHLOROETHYLENE IHIBITS VOLTAGE-SENSITIVE CALCIUM CURRENTS IN DIFFERENTIATED PC 12 CELLS.

    EPA Science Inventory

    ABSTRACT BODY: It has been demonstrated recently that volatile organic compounds (VOCs)such as toluene, perchloroethylene and trichloroethylene inhibit function of voltage-sensitive calcium channels (VSSC). Such actions are hypothesized to contribute to the acute neurotoxicity of...

  8. Trichloroethylene. I. Carcinogenicity of trichloroethylene.

    PubMed

    Motohashi, N; Nagashima, H; Molnár, J

    1999-01-01

    Trichloroethylene (TCE) as an industrial pollutant may damage human health and can be considered as carcinogen. TCE has been detected in the environment and in various human organs, e.g., liver, kidney and brain etc. There are histological alterations such as depletion of glycogen and hydropic degeneration in the liver, however, other signs of TCE effects can be found in various organs as well. TCE and its metabolites, e.g., trichlorethanol, trichloro-acetic acid and epoxides were recently identified as strong mutagens in Ames mutagenicity test inducing frameshift and base-substitution mutations. TCE induced predominantly hepatocellular carcinoma after long term administration in mice. In these animals, kidneys and liver were supposed to be primary target organs with low epoxy-hydrolase activity. A high level of mitotic gene conversion (or gene rearrangement) was indicated by the metabolism of TCE after repeated administration. Purified TCE by was a weak mutagen in the presence of S9 microsomal fraction of rats and as a consequence, the carcinogenic activity was low in the kidney of rats. However, a dose related increase of Leydig cell tumors was found in male rats. PMID:10459493

  9. CONSTITUTIVE DEGRADATION OF TRICHLOROETHYLENE BY AN ALTERED BACTERIUM IN A GAS-PHASE BIOREACTOR

    EPA Science Inventory

    Pseudomonas cepacia G4 expresses a unique toluene ortho-monooxygenase (Tom) that enables it to degrade toluene and trichloroethylene (TCE). ransposon mutants of G4 have been isolated that constitutively express Tom. wo fixed-film bioreactor designs were investigated for the explo...

  10. Mechanism of pentachloroethane dehydrochlorination to tetrachloroethylene

    SciTech Connect

    Roberts, A.L.; Gschwend, P.M. )

    1991-01-01

    The dehydrochlorination of pentachloroethane to tetrachloroethylene was investigated to gain insight into mechanisms of hexachloroethane reduction as well as structure-reactivity relationships for polyhalogenated alkanes. Although the absence of deuterium exchange excludes the possibility of an (E{sub 1CB}){sub R} mechanism, several factors suggest the transition state possesses considerable carbanion character: the reaction is insensitive to buffer catalysis, exhibits a moderately large solvent kinetic isotope effect, and only displays a neutral mechanism at low pH. Though our results cannot rule out a stepwise (E{sub 1CB}){sub I} or (E{sub 1CB}){sub ip} sequence, we believe CHCl{sub 2}CCl{sub 3} reacts via a concerted mechanism based on a comparison of its dehydrohalogenation kinetics with proton-exchange rates for CHCl{sub 3} and CHCl{sub 2}CF{sub 3}. Pentachloroethane reported in the reduction of hexachloroethane to tetrachloroethylene is unlikely to result from carbanion protonation. Rather, it may be diagnostic of free-radical reduction mechanisms. Because pentachloroethane reacts relatively rapidly, future studies of hexachloroethane reduction should consider whether pentachloroethane represents a reaction intermediate instead of dismissing it as a minor side product.

  11. Cometabolic biodegradation of trichloroethylene in a biofilm reactor

    SciTech Connect

    Arcangeli, J.P.; Arvin, E.; Jensen, H.M.

    1995-12-31

    Cometabolic degradation of trichloroethylene (TCE) in an aerobic biofilm system with toluene as primary substrate was investigated. TCE degradation rate was first-order, giving an average first-order surface removal rate constant, k{sub 1,a}, of 0.26 m/d. TCE was probably degraded by a toluene-induced enzyme. However, if toluene was provided in high concentrations, degradation of TCE was inhibited. Furthermore, it appeared that TCE inhibited toluene degradation. This inhibition increased with the TCE concentration in the reactor, but it decreased with an increasing toluene concentration. The authors conclude that these interactions could be the result of a competitive inhibition between TCE and toluene. Practically, this shows that degradation of TCE can be maximized if an optimum concentration of toluene is provided. An example presented in this paper reveals that the optimum toluene concentration was in the range of 200 to 500 {micro}g/L for a TCE inlet concentration of 135 {micro}g/L. Under these optimal conditions, the TCE degradation rate was 0.045 g m{sup {minus}2} d{sup {minus}1}, leading to a first-order surface removal rate constant of 0.4 m/d and a transformation yield of 0.05 g TCE/g toluene degraded.

  12. ROUTE-DEPENDENT EFFECTS OF TOLUENE ON SIGNAL DETECTION BEHAVIOR IN RATS.

    EPA Science Inventory

    The acute effects of toluene and other solvents on behavior are thought to depend upon their concentration in the brain. We have shown previously that inhaled toluene and trichloroethylene disrupt sustained attention in rats as assessed with a visual signal detection task (SDT). ...

  13. TRICHLOROETHYLENE (TCE) ISSUE PAPERS

    EPA Science Inventory

    These issue papers are a part of EPA's effort to develop a trichloroethylene (TCE) human health risk assessment. These issue papers were developed by EPA to provide scientific and technical information to the National Academy of Sciences (NAS) for use in developing their advice ...

  14. Induction of the tod operon by trichloroethylene in Pseudomonas putida TVA8

    SciTech Connect

    Shingleton, J.T.; Applegate, B.M.; Nagel, A.C.; Bienkowski, P.R.; Sayler, G.S.

    1998-12-01

    Bioluminescence, mRNA levels, and toluene degradation rates in Pseudomonas putida TVA8 were measured as a function of various concentrations of toluene and trichloroethylene (TCE). TVA8 showed an increasing bioluminescence response to increasing TCE and toluene concentrations. Compared to uninduced TVA8 cultures, todC1 mRNA levels increased 11-fold for TCE-treated cultures and 13-fold for toluene-treated cultures. Compared to uninduced P. putida F1 cultures, todC1 mRNA levels increased 4,4-fold for TCE-induced cultures and 4.9-fold for toluene-induced cultures. Initial toluene degradation rates were linearly correlated with specific bioluminescence in TVA8 cultures.

  15. Reductive dechlorination of Tri- and tetrachloroethylenes depends on transition from aerobic to anaerobic conditions.

    PubMed Central

    Kästner, M

    1991-01-01

    Aerobic enrichment cultures from contaminated groundwaters dechlorinated trichloroethylene (TCE) (14.6 mg/liter; 111 mumol/liter) and tetrachloroethylene (PCE) (16.2 mg/liter; 98 mumol/liter) reductively within 4 days after the transition from aerobic to anaerobic conditions. The transformation products were equimolar amounts of cis-1,2-dichloroethylene and traces of 1,1-dichloroethylene. No other chlorinated product and no methane were detected. The change was accompanied by the release of sulfide, which caused a decrease in the redox potential from 0 to -150 mV. In sterile control experiments, sulfide led to the abiotic formation of traces of 1,1-dichloroethylene without cis-1,2-dichloroethylene production. The reductive dechlorination of PCE via TCE depended on these specific transition conditions after consumption of the electron acceptor oxygen or nitrate. Repeated feeding of TCE or PCE to cultures after the change to anaerobic conditions yielded no further dechlorination. Only aerobic subcultures with an air/liquid ratio of 1:4 maintained dechlorination activities; anaerobic subcultures showed no transformation. Bacteria from noncontaminated sites showed no reduction under the same conditions. PMID:1892393

  16. Reductive dechlorination of Tri- and tetrachloroethylenes depends on transition from aerobic to anaerobic conditions.

    PubMed

    Kästner, M

    1991-07-01

    Aerobic enrichment cultures from contaminated groundwaters dechlorinated trichloroethylene (TCE) (14.6 mg/liter; 111 mumol/liter) and tetrachloroethylene (PCE) (16.2 mg/liter; 98 mumol/liter) reductively within 4 days after the transition from aerobic to anaerobic conditions. The transformation products were equimolar amounts of cis-1,2-dichloroethylene and traces of 1,1-dichloroethylene. No other chlorinated product and no methane were detected. The change was accompanied by the release of sulfide, which caused a decrease in the redox potential from 0 to -150 mV. In sterile control experiments, sulfide led to the abiotic formation of traces of 1,1-dichloroethylene without cis-1,2-dichloroethylene production. The reductive dechlorination of PCE via TCE depended on these specific transition conditions after consumption of the electron acceptor oxygen or nitrate. Repeated feeding of TCE or PCE to cultures after the change to anaerobic conditions yielded no further dechlorination. Only aerobic subcultures with an air/liquid ratio of 1:4 maintained dechlorination activities; anaerobic subcultures showed no transformation. Bacteria from noncontaminated sites showed no reduction under the same conditions. PMID:1892393

  17. Kinetics of tetrachloroethylene-reductive dechlorination catalyzed by vitamin B{sub 12}

    SciTech Connect

    Burris, D.R.; Deng, B.; Buck, L.E.; Hatfield, K.

    1998-09-01

    Reductive dechlorination kinetics of tetrachloroethylene (PCE) to ethylene catalyzed by vitamin B{sub 12} using Ti[III] citrate as the bulk reductant was examined in a vapor-water batch system. A kinetic model incorporating substrate-B{sub 12} electron-transfer complex formation and subsequent product release was developed. The model also accounted for the primary reductive dechlorination pathways (hydrogenolysis and reductive {beta} elimination) and vapor/water-phase partitioning. Reaction rate constants were sequentially determined by fitting the model to experimental kinetic data while moving upward through consecutive reaction pathways. The release of product from the complex was found to be second order with respect to substrate concentration for both PCE and acetylene; all other substrates appeared to release by first order. Reductive {beta} elimination was found to be a significant reaction pathway for trichloroethylene (TCE), and chloroacetylene was observed as a reactive intermediate. Acetylene production appears to be primarily due to the reduction of chloroacetylene derived from TCE. The reduction of cis-dichloroethylene (cis-DCE), the primary DCE isomer formed, was extremely slow, leading to a significant buildup of cis-DCE. The kinetics of acetylene and vinyl chloride reduction appeared to be limited by the formation of relatively stable substrate-B{sub 12} complexes. The relatively simple model examined appears to adequately represent the main features of the experimental data.

  18. IRIS TOXICOLOGICAL REVIEW OF TETRACHLOROETHYLENE (PERCHLOROETHYLENE) (INTERAGENCY SCIENCE DISCUSSION DRAFT)

    EPA Science Inventory

    EPA is releasing the draft report, Toxicological Review of Tetrachloroethylene (Perchloroethylene), that was distributed to Federal agencies and White House Offices for comment during the Science Discussion step of the IRIS Assessment...

  19. SURFACTANT ENHANCED REMEDIATION OF SOIL COLUMNS CONTAMINATED BY RESIDUAL TETRACHLOROETHYLENE

    EPA Science Inventory

    The ability of aqueous surfactant solutions to recover tetrachloroethylene (PCE) entrapped in Ottawa sand was evaluated in four column experiments. Residual PCE was emplaced by injecting 14C-labeled PCE into water-saturated soil columns and displacing the free product ...

  20. IRIS Toxicological Review of Tetrachloroethylene (Perchloroethylene) (External Review Draft)

    EPA Science Inventory

    EPA conducted a peer review of the scientific basis supporting the human health hazard and dose-response assessment of tetrachloroethylene that will appear on the Integrated Risk Information System (IRIS) database. Peer review is meant to ensure that science is used credibly and ...

  1. Biodegradation of Trichloroethylene by an Endophyte of Hybrid Poplar

    PubMed Central

    Kang, Jun Won; Khan, Zareen

    2012-01-01

    We isolated and characterized a novel endophyte from hybrid poplar. This unique endophyte, identified as Enterobacter sp. strain PDN3, showed high tolerance to trichloroethylene (TCE). Without the addition of inducers, such as toluene or phenol, PDN3 rapidly reduced TCE levels in medium from 72.4 μM to 30.1 μM in 24 h with a concurrent release of 127 μM chloride ion, and nearly 80% of TCE (55.3 μM) was dechlorinated by PDN3 in 5 days with 166 μM chloride ion production, suggesting TCE degradation. PMID:22367087

  2. 40 CFR Appendix J to Part 122 - NPDES Permit Testing Requirements for Publicly Owned Treatment Works (§ 122.21(j))

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... chloride Methylene chloride 1,1,2,2-tetrachloroethane Tetrachloroethylene Toluene 1,1,1-trichloroethane 1,1,2-trichloroethane Trichloroethylene Vinyl chloride Acid-extractable compounds P-chloro-m-creso...

  3. 40 CFR Appendix J to Part 122 - NPDES Permit Testing Requirements for Publicly Owned Treatment Works (§ 122.21(j))

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... chloride Methylene chloride 1,1,2,2-tetrachloroethane Tetrachloroethylene Toluene 1,1,1-trichloroethane 1,1,2-trichloroethane Trichloroethylene Vinyl chloride Acid-extractable compounds P-chloro-m-creso...

  4. 40 CFR Table 8 to Subpart G of... - Organic HAP's Subject to the Wastewater Provisions for Process Units at New Sources

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 75343 (1,1-Dichloroethane). Hexachlorobutadiene 87683 Hexachloroethane 67721 Hexane 100543 Methyl bromide (Bromomethane) 74839 Methyl chloride (Chloromethane) 74873 Phosgene 75445 Tetrachloroethylene (Perchloroethylene) 127184 Toluene 108883 Trichloroethane (1,1,1-) (Methyl chloroform) 71556 Trichloroethylene...

  5. 40 CFR Table 8 to Subpart G of... - Organic HAP's Subject to the Wastewater Provisions for Process Units at New Sources

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 75343 (1,1-Dichloroethane). Hexachlorobutadiene 87683 Hexachloroethane 67721 Hexane 100543 Methyl bromide (Bromomethane) 74839 Methyl chloride (Chloromethane) 74873 Phosgene 75445 Tetrachloroethylene (Perchloroethylene) 127184 Toluene 108883 Trichloroethane (1,1,1-) (Methyl chloroform) 71556 Trichloroethylene...

  6. 40 CFR Table 8 to Subpart G of... - Organic HAP's Subject to the Wastewater Provisions for Process Units at New Sources

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 75343 (1,1-Dichloroethane). Hexachlorobutadiene 87683 Hexachloroethane 67721 Hexane 100543 Methyl bromide (Bromomethane) 74839 Methyl chloride (Chloromethane) 74873 Phosgene 75445 Tetrachloroethylene (Perchloroethylene) 127184 Toluene 108883 Trichloroethane (1,1,1-) (Methyl chloroform) 71556 Trichloroethylene...

  7. 40 CFR Table 8 to Subpart G of... - Organic HAP's Subject to the Wastewater Provisions for Process Units at New Sources

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-Dichloroethane). Hexachlorobutadiene 87683 Hexachloroethane 67721 Hexane 100543 Methyl bromide (Bromomethane) 74839 Methyl chloride (Chloromethane) 74873 Phosgene 75445 Tetrachloroethylene (Perchloroethylene) 127184 Toluene 108883 Trichloroethane (1,1,1-) (Methyl chloroform) 71556 Trichloroethylene...

  8. 40 CFR Table 8 to Subpart G of... - Organic HAP's Subject to the Wastewater Provisions for Process Units at New Sources

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-Dichloroethane). Hexachlorobutadiene 87683 Hexachloroethane 67721 Hexane 100543 Methyl bromide (Bromomethane) 74839 Methyl chloride (Chloromethane) 74873 Phosgene 75445 Tetrachloroethylene (Perchloroethylene) 127184 Toluene 108883 Trichloroethane (1,1,1-) (Methyl chloroform) 71556 Trichloroethylene...

  9. Lactate Injection by Electric Currents for Bioremediation of Tetrachloroethylene in Clay

    PubMed Central

    Wu, Xingzhi; Gent, David B.; Davis, Jeffrey L.; Alshawabkeh, Akram N.

    2012-01-01

    Biological transformation of tetrachloroethylene (PCE) in silty clay samples by ionic injection of lactate under electric fields is evaluated. To prepare contaminated samples, a silty clay slurry was mixed with PCE, inoculated with KB-1® dechlorinators and was consolidated in a 40 cm long cell. A current density between 5.3 and 13.3 A m−2 was applied across treated soil samples while circulating electrolytes containing 10 mg L−1 lactate concentration between the anode and cathode compartments to maintain neutral pH and chemically reducing boundary conditions. The total adsorbed and aqueous PCE was degraded in the soil to trichloroethylene (TCE), cis-1,2-dichloroethene (cis-DCE), vinyl chloride (VC) and ethene in 120 d, which is about double the time expected for transformation. Lactate was delivered into the soil by a reactive transport rate of 3.7 cm2 d−1 V−1. PCE degradation in the clay samples followed zero order transformation rates ranging from 1.5 to 5 mg L−1 d−1 without any significant formation of TCE. cis-DCE transformation followed first order transformation rates of 0.06 to 0.10 per day. A control experiment conducted with KB-1 and lactate, but without electricity did not show any significant lactate buildup or cis-DCE transformation because the soil was practically impermeable (hydraulic conductivity of 2×10−7 cm s−1). It is concluded that ionic migration will deliver organic additives and induce biological activity and complete PCE transformation in clay, even though the transformation occurs under slower rates compared to ideal conditions. PMID:23264697

  10. UNCERTAINTIES IN TRICHLOROETHYLENE PHARMACOKINETIC MODELS

    EPA Science Inventory

    Understanding the pharmacokinetics of a chemical¯its absorption, distribution, metabolism, and excretion in humans and laboratory animals ¯ is critical to the assessment of its human health risks. For trichloroethylene (TCE), numerous physiologically-based pharmacokinetic (PBPK)...

  11. Constitutive degradation of trichloroethylene by an altered bacterium in a gas-phase bioreactor. Book chapter

    SciTech Connect

    Shields, M.S.; Reagin, M.J.; Gerger, R.R.; Somerville, C.; Schaubhut, R.

    1994-01-01

    Pseudomonas cepacia G4 expresses a unique toluene orth-monooxygenase (Tom) that enables it to degrade toluene and trichloroethylene (TCE). Transposon mutants of G4 have been isolated that constitutively express Tom. Two fixed-film bioreactor designs were investigated for the exploitation of one such constitutive strain (G4 PR1) in the degradation of vapor-phase TCE. DNA probe analysis indicates that the genes responsible for the toluene catabolic pathway are located on a large plasmid of G4 (> or = 150 kb) termed pG4L. The authors propose that pG4L will serve as a archetype for a new class of catabolic plasmid known as Tom, which encodes an ortho-hydroxylation pathway for the degradation of benzene, toluene, o-xylene, cresols, and phenol.

  12. Mutants of Pseudomonas cepacia G4 defective in catabolism of aromatic compounds and trichloroethylene.

    PubMed Central

    Shields, M S; Montgomery, S O; Cuskey, S M; Chapman, P J; Pritchard, P H

    1991-01-01

    Pseudomonas cepacia G4 possesses a novel pathway of toluene catabolism that is shown to be responsible for the degradation of trichloroethylene (TCE). This pathway involves conversion of toluene via o-cresol to 3-methylcatechol. In order to determine the enzyme of toluene degradation that is responsible for TCE degradation, chemically induced mutants, blocked in the toluene ortho-monooxygenase (TOM) pathway of G4, were examined. Mutants of the phenotypic class designated TOM A- were all defective in their ability to oxidize toluene, o-cresol, m-cresol, and phenol, suggesting that a single enzyme is responsible for conversion of these compounds to their hydroxylated products (3-methylcatechol from toluene, o-cresol, and m-cresol and catechol from phenol) in the wild type. Mutants of this class did not degrade TCE. Two other mutant classes which were blocked in toluene catabolism, TOM B-, which lacked catechol-2,3-dioxygenase, and TOM C-, which lacked 2-hydroxy-6-oxoheptadienoic acid hydrolase activity, were fully capable of TCE degradation. Therefore, TCE degradation is directly associated with the monooxygenation capability responsible for toluene, cresol, and phenol hydroxylation. PMID:1892384

  13. Human Health Effects of Tetrachloroethylene: Key Findings and Scientific Issues

    PubMed Central

    Hogan, Karen A.; Scott, Cheryl Siegel; Cooper, Glinda S.; Bale, Ambuja S.; Kopylev, Leonid; Barone, Stanley; Makris, Susan L.; Glenn, Barbara; Subramaniam, Ravi P.; Gwinn, Maureen R.; Dzubow, Rebecca C.; Chiu, Weihsueh A.

    2014-01-01

    Background: The U.S. Environmental Protection Agency (EPA) completed a toxicological review of tetrachloroethylene (perchloroethylene, PCE) in February 2012 in support of the Integrated Risk Information System (IRIS). Objectives: We reviewed key findings and scientific issues regarding the human health effects of PCE described in the U.S. EPA’s Toxicological Review of Tetrachloroethylene (Perchloroethylene). Methods: The updated assessment of PCE synthesized and characterized a substantial database of epidemiological, experimental animal, and mechanistic studies. Key scientific issues were addressed through modeling of PCE toxicokinetics, synthesis of evidence from neurological studies, and analyses of toxicokinetic, mechanistic, and other factors (tumor latency, severity, and background rate) in interpreting experimental animal cancer findings. Considerations in evaluating epidemiological studies included the quality (e.g., specificity) of the exposure assessment methods and other essential design features, and the potential for alternative explanations for observed associations (e.g., bias or confounding). Discussion: Toxicokinetic modeling aided in characterizing the complex metabolism and multiple metabolites that contribute to PCE toxicity. The exposure assessment approach—a key evaluation factor for epidemiological studies of bladder cancer, non-Hodgkin lymphoma, and multiple myeloma—provided suggestive evidence of carcinogenicity. Bioassay data provided conclusive evidence of carcinogenicity in experimental animals. Neurotoxicity was identified as a sensitive noncancer health effect, occurring at low exposures: a conclusion supported by multiple studies. Evidence was integrated from human, experimental animal, and mechanistic data sets in assessing adverse health effects of PCE. Conclusions: PCE is likely to be carcinogenic to humans. Neurotoxicity is a sensitive adverse health effect of PCE. Citation: Guyton KZ, Hogan KA, Scott CS, Cooper GS, Bale AS

  14. Toluene emissions from plants

    NASA Astrophysics Data System (ADS)

    Heiden, A. C.; Kobel, K.; Komenda, M.; Koppmann, R.; Shao, M.; Wildt, J.

    The emission of toluene from different plants was observed in continuously stirred tank reactors and in field measurements. For plants growing without stress, emission rates were low and ranged from the detection limit up to 2·10-16 mol·cm-2·s-1. Under conditions of stress, the emission rates exceeded 10-14 mol·cm-2·s-1. Exposure of sunflower (Helianthus annuus L. cv. Gigantheus) to 13CO2 resulted in 13C-labeling of the emitted toluene on a time scale of hours. Although no biochemical pathway for the production of toluene is known, these results indicate that toluene is synthesized by the plants. The emission rates of toluene from sunflower are dependent on nutrient supply and wounding. Since α-pinene emission rates are also influenced by these factors, toluene and α-pinene emissions show a high correlation. During pathogen attack on Scots pines (Pinus sylvestris L.) significant toluene emissions were observed. In this case emissions of toluene and α-pinene also show a good correlation. Toluene emissions were also found in field experiments with pines using branch enclosures.

  15. Metabolism of trichloroethylene.

    PubMed Central

    Lash, L H; Fisher, J W; Lipscomb, J C; Parker, J C

    2000-01-01

    A major focus in the study of metabolism and disposition of trichloroethylene (TCE) is to identify metabolites that can be used reliably to assess flux through the various pathways of TCE metabolism and to identify those metabolites that are causally associated with toxic responses. Another important issue involves delineation of sex- and species-dependent differences in biotransformation pathways. Defining these differences can play an important role in the utility of laboratory animal data for understanding the pharmacokinetics and pharmacodynamics of TCE in humans. Sex-, species-, and strain-dependent differences in absorption and distribution of TCE may play some role in explaining differences in metabolism and susceptibility to toxicity from TCE exposure. The majority of differences in susceptibility, however, are likely due to sex-, species-, and strain-dependent differences in activities of the various enzymes that can metabolize TCE and its subsequent metabolites. An additional factor that plays a role in human health risk assessment for TCE is the high degree of variability in the activity of certain enzymes. TCE undergoes metabolism by two major pathways, cytochrome P450 (P450)-dependent oxidation and conjugation with glutathione (GSH). Key P450-derived metabolites of TCE that have been associated with specific target organs, such as the liver and lungs, include chloral hydrate, trichloroacetate, and dichloroacetate. Metabolites derived from the GSH conjugate of TCE, in contrast, have been associated with the kidney as a target organ. Specifically, metabolism of the cysteine conjugate of TCE by the cysteine conjugate ss-lyase generates a reactive metabolite that is nephrotoxic and may be nephrocarcinogenic. Although the P450 pathway is a higher activity and higher affinity pathway than the GSH conjugation pathway, one should not automatically conclude that the latter pathway is only important at very high doses. A synthesis of this information is then

  16. Exposure assessment of trichloroethylene.

    PubMed Central

    Wu, C; Schaum, J

    2000-01-01

    This article reviews exposure information available for trichloroethylene (TCE) and assesses the magnitude of human exposure. The primary sources releasing TCE into the environment are metal cleaning and degreasing operations. Releases occur into all media but mostly into the air due to its volatility. It is also moderately soluble in water and can leach from soils into groundwater. TCE has commonly been found in ambient air, surface water, and groundwaters. The 1998 air levels in microg/m(3) across 115 monitors can be summarized as follows: range = 0.01-3.9, mean = 0.88. A California survey of large water utilities in 1984 found a median concentration of 3.0 microg/L. General population exposure to TCE occurs primarily by inhalation and water ingestion. Typical average daily intakes have been estimated as 11-33 microg/day for inhalation and 2-20 microg/day for ingestion. A small portion of the population is expected to have elevated exposures as a result of one or more of these pathways: inhalation exposures to workers involved in degreasing operations, ingestion and inhalation exposures occurring in homes with private wells located near disposal/contamination sites, and inhalation exposures to consumers using TCE products in areas of poor ventilation. More current and more extensive data on TCE levels in indoor air, water, and soil are needed to better characterize the distribution of background exposures in the general population and elevated exposures in special subpopulations. Images Figure 1 PMID:10807565

  17. Pharmacological classification of the abuse-related discriminative stimulus effects of trichloroethylene vapor

    PubMed Central

    Shelton, Keith L.; Nicholson, Katherine L.

    2014-01-01

    Inhalants are distinguished as a class primarily based upon a shared route of administration. Grouping inhalants according to their abuse-related in vivo pharmacological effects using the drug discrimination procedure has the potential to provide a more relevant classification scheme to the research and treatment community. Mice were trained to differentiate the introceptive effects of the trichloroethylene vapor from air using an operant procedure. Trichloroethylene is a chlorinated hydrocarbon solvent once used as an anesthetic as well as in glues and other consumer products. It is now primarily employed as a metal degreaser. We found that the stimulus effects of trichloroethylene were similar to those of other chlorinated hydrocarbon vapors, the aromatic hydrocarbon toluene and the vapor anesthetics methoxyflurane and isoflurane. The stimulus effects of trichloroethylene overlapped with those of the barbiturate methohexital, to a lesser extent the benzodiazepine midazolam and to ethanol. NMDA antagonists, the kappa opioid agonist U50,488 and the mixed 5-HT agonist mCPP largely failed to substitute for trichloroethylene. These data suggest that stimulus effects of chlorinated hydrocarbon vapors are mediated at least partially by GABAA receptor positive modulatory effects. PMID:25202471

  18. Death due to acute tetrachloroethylene intoxication in a chronic abuser.

    PubMed

    Amadasi, Alberto; Mastroluca, Lavinia; Marasciuolo, Laura; Caligara, Marina; Sironi, Luca; Gentile, Guendalina; Zoja, Riccardo

    2015-05-01

    Volatile substances are used widespread, especially among young people, as a cheap and easily accessible drug. Tetrachloroethylene is one of the solvents exerting effects on the central nervous system with experiences of disinhibition and euphoria. The case presented is that of a 27-year-old female, found dead by her father at home with cotton swabs dipped in the nostrils. She was already known for this type of abuse and previously admitted twice to the hospital for nonfatal acute poisonings. The swabs were still soaked in tetrachloroethylene. Toxicological and histological investigations demonstrated the presence of an overlap between chronic intake of the substance (with high concentrations in sites of accumulation, e.g., the adipose tissue, and contemporary tissue damage, as histologically highlighted) and acute intoxication as final cause of death, with a concentration of 158 mg/L in cardiac blood and 4915 mg/kg in the adipose tissue. No other drugs or medicines were detected in body fluids or tissues, and to our knowledge, this is the highest concentration ever detected in forensic cases. This peculiar case confirms the toxicity of this substance and focuses on the importance of complete histological and toxicological investigations in the distinction between chronic abuse and acute intoxication. PMID:25605280

  19. Trichloroethylene. I. An overview.

    PubMed

    Waters, E M; Gerstner, H B; Huff, J E

    1977-01-01

    Trichloroethylene (TCE) has been an industrial chemical of some importance for the past 50 years. First synthesized by Fischer in 1864, TCE has enjoyed considerable industrial usage as a degreaser and limited medical use as an inhalation anesthetic and analgesic. This TCE overview provides a narrative survey of the reference literature. Highlights include history, nomenclature, physical and chemical properties, manufacture, analysis, uses, metabolism, toxicology, carcinogenic potential, exposure routes, recommended standards, and conclusions. Chemically, TCE is a colorless, highly volatile liquid of molecular formula C2HCl3. Autoxidation of the unstable compound yields acidic products. Stabilizers are added to retard decomposition. TCE's multitude of industrial uses center around its highly effective fat-solvent properties. Metabolically, TCE is transformed in the liver to trichloroacetic acid, trichloroethanol, and trichloroethanol glucuronide; these breakdown products are excreted through the kidneys. Most toxic responses occur as a result of industrial exposures. TCE affects principally the central nervous system (CNS). Short exposures result in subjective symptoms such as headache, nausea, and incoordination. Longer exposures may result in CNS depression, hepatorenal failure, and increased cardiac output. Cases of sudden death following TCE exposure are generally attributed to ventricular fibrillation. Current interest in TCE has focused on recent experimental data that implicate TCE as a cause of hepatocellular carcinoma in mice. No epidemiological data are available that demonstrate a similar action in humans. The overall population may be exposed to TCE through household cleaning fluids, decaffeinated coffee, and some spice extracts. The NIOSH recommended standard for TCE is 100 ppm as a time-weighted average for an 8-hr day, with a maximum allowable peak concentration of 150 ppm for 10 min. PMID:403297

  20. Trichloroethylene and cancer: epidemiologic evidence.

    PubMed Central

    Wartenberg, D; Reyner, D; Scott, C S

    2000-01-01

    Trichloroethylene is an organic chemical that has been used in dry cleaning, for metal degreasing, and as a solvent for oils and resins. It has been shown to cause liver and kidney cancer in experimental animals. This article reviews over 80 published papers and letters on the cancer epidemiology of people exposed to trichloroethylene. Evidence of excess cancer incidence among occupational cohorts with the most rigorous exposure assessment is found for kidney cancer (relative risk [RR] = 1.7, 95% confidence interval [CI] 1.1-2.7), liver cancer (RR = 1.9, 95% CI(1.0-3.4), and non-Hodgkin's lymphoma (RR = 1.5, 95% CI 0.9-2.3) as well as for cervical cancer, Hodgkin's disease, and multiple myeloma. However, since few studies isolate trichloroethylene exposure, results are likely confounded by exposure to other solvents and other risk factors. Although we believe that solvent exposure causes cancer in humans and that trichloroethylene likely is one of the active agents, we recommend further study to better specify the specific agents that confer this risk and to estimate the magnitude of that risk. PMID:10807550

  1. Health assessment for Malvern Trichloroethylene, Malvern, Pennsylvania, Region 3. CERCLIS No. PAD014353445. Preliminary report

    SciTech Connect

    Not Available

    1989-01-19

    The Malvern Trichloroethylene (TCE) Site (MTS) is in Malvern(Chester County) Pennsylvania. From 1952 to 1976 drums containing various wastes including volatile organic compounds and PCBs were dumped on-site. Preliminary on-site groundwater sampling results have identified TCE (ND to 1,330 ppm), perchloroethylene (PCE) (7 to 1,170 ppm), 1,1,1-trichloroethane (TCA) (12 to 2,230 ppm), and tetrachloroethylene (ND to 22,000 ppb). In addition, PCBs were identified in soil (1,350 ppm) and in drums. The site is considered to be of public health concern because of the risk to human health caused by the possibility of human exposure to hazardous substances.

  2. The use of biofilters to improve indoor air quality: the removal of toluene, TCE, and formaldehyde.

    PubMed

    Darlington, A; Dixon, M A; Pilger, C

    1998-01-01

    A biofilter composed of a scrubber, a hydroponic planting system, and an aquatic system with green plants as a base maintained air quality within part of a modern office building. The scrubber was composed of five parallel fiberglass modules with external faces of porous lava rock. The face, largely covered with mosses, was wetted by recirculating water. Air was drawn through the scrubber and the immediately adjacent hydroponic region by a dedicated air handling system. The system was challenged for 4 weeks with three common indoor organic pollutants and removed significant amounts of all compounds. A single pass through the scrubber removed 10% of the trichloroethylene and 50% of the toluene. A single pass lowered formaldehyde air concentrations to 13 micrograms m-3 irrespective of influent levels (ranging between 30 and 90 micrograms m-3). The aquatic system accumulated trichloroethylene but neither toluene nor formaldehyde, suggesting the rapid breakdown of these materials. The botanical components removed some pollutants. PMID:11540466

  3. Enhancing trichloroethylene degradation using non-aromatic compounds as growth substrates.

    PubMed

    Kim, Seungjin; Hwang, Jeongmin; Chung, Jinwook; Bae, Wookeun

    2014-06-30

    The effect of non-aromatic compounds on the trichloroethylene (TCE) degradation of toluene-oxidizing bacteria were evaluated using Burkholderia cepacia G4 that expresses toluene 2-monooxygenase and Pseudomonas putida that expresses toluene dioxygenase. TCE degradation rates for B. cepacia G4 and P. putida with toluene alone as growth substrate were 0.144 and 0.123 μg-TCE/mg-protein h, respectively. When glucose, acetate and ethanol were fed as additional growth substrates, those values increased up to 0.196, 0.418 and 0.530 μg-TCE/mg-protein h, respectively for B. cepacia G4 and 0.319, 0.219 and 0.373 μg-TCE/mg-protein h, respectively for P. putida. In particular, the addition of ethanol resulted in a high TCE degradation rate regardless of the initial concentration. The use of a non-aromatic compound as an additional substrate probably enhanced the TCE degradation because of the additional supply of NADH that is consumed in co-metabolic degradation of TCE. Also, it is expected that the addition of a non-aromatic substrate can reduce the necessary dose of toluene and, subsequently, minimize the potential competitive inhibition upon TCE co-metabolism by toluene. PMID:24857894

  4. Prenatal and Early Childhood Exposure to Tetrachloroethylene and Adult Vision

    PubMed Central

    Getz, Kelly D.; Janulewicz, Patricia A.; Rowe, Susannah; Weinberg, Janice M.; Winter, Michael R.; Martin, Brett R.; Vieira, Veronica M.; White, Roberta F.

    2012-01-01

    Background: Tetrachloroethylene (PCE; or perchloroethylene) has been implicated in visual impairments among adults with occupational and environmental exposures as well as children born to women with occupational exposure during pregnancy. Objectives: Using a population-based retrospective cohort study, we examined the association between prenatal and early childhood exposure to PCE-contaminated drinking water on Cape Cod, Massachusetts, and deficits in adult color vision and contrast sensitivity. Methods: We estimated the amount of PCE that was delivered to the family residence from participants’ gestation through 5 years of age. We administered to this now adult study population vision tests to assess acuity, contrast sensitivity, and color discrimination. Results: Participants exposed to higher PCE levels exhibited lower contrast sensitivity at intermediate and high spatial frequencies compared with unexposed participants, although the differences were generally not statistically significant. Exposed participants also exhibited poorer color discrimination than unexposed participants. The difference in mean color confusion indices (CCI) was statistically significant for the Farnsworth test but not Lanthony’s D-15d test [Farnsworth CCI mean difference = 0.05, 95% confidence interval (CI): 0.003, 0.10; Lanthony CCI mean difference = 0.07, 95% CI: –0.02, 0.15]. Conclusions: Prenatal and early childhood exposure to PCE-contaminated drinking water may be associated with long-term subclinical visual dysfunction in adulthood, particularly with respect to color discrimination. Further investigation of this association in similarly exposed populations is necessary. PMID:22784657

  5. Potential waste minimization of trichloroethylene and perchloroethylene via aerobic biodegradation.

    PubMed

    Wang, Jian; Cutright, Teresa J

    2005-01-01

    Trichloroethylene (TCE) and perchloroethylene (PCE) are two of the most frequently detected chlorinated organics found in groundwater. Biodegradation with a new aerobic consortium was used to ascertain the viability of bioremediation for waste minimization applications. After 1 week of treatment, the degradation rate constants, k, were between 0.004 and 0.012 d(-1) for initial concentrations of 54-664 microM TCE. When PCE was used as the sole contaminant, the k values were approximately 0.01 d(-1) regardless of the initial concentration. The addition of 0.2 microM toluene or phenol as an inducer dramatically increased TCE degradation. For instance, at 200 microM TCE the k value when toluene was added (0.03 d(-1)) was 2.2 times higher than without inducers (0.009 d(-1)). The addition of 0.2 microM phenol increased the rate constant by 58%. However, PCE degradation rates were not changed significantly. PMID:15991724

  6. Benzene and toluene biodegradation down gradient of a zero-valent iron permeable reactive barrier.

    PubMed

    Chen, Liang; Liu, Fei; Liu, Yulong; Dong, Hongzhong; Colberg, Patricia J S

    2011-04-15

    This study simulated benzene and toluene biodegradation down gradient of a zero-valent iron permeable reactive barrier (ZVI PRB) that reduces trichloroethylene (TCE). The effects of elevated pH (10.5) and the presence of a common TCE dechlorination by product [cis-1,2-dichloroethene (cis-1,2-DCE)] on benzene and toluene biodegradation were evaluated in batch experiments. The data suggest that alkaline pH (pH 10.5), often observed down gradient of ZVI PRBs, inhibits Fe(III)-mediated biotransformation of both benzene and toluene. Removal was reduced by 43% for benzene and 26% for toluene as compared to the controls. The effect of the addition of cis-1,2-DCE on benzene and toluene biodegradation was positive and resulted in removal that was greater than or equal to the controls. These results suggest that, at least for cis-1,2-DCE, its formation may not be toxic to iron-reducing benzene and toluene degrading bacteria; however, for microbial benzene and toluene removal down gradient of a ZVI PRB, it may be necessary to provide pH control, especially in the case of a biological PRB that is downstream from a ZVI PRB. PMID:21316847

  7. Addition of Aromatic Substrates Restores Trichloroethylene Degradation Activity in Pseudomonas putida F1

    PubMed Central

    Morono, Yuki; Unno, Hajime; Tanji, Yasunori; Hori, Katsutoshi

    2004-01-01

    The rate of trichloroethylene (TCE) degradation by toluene dioxygenase (TDO) in resting cells of Pseudomonas putida F1 gradually decreased and eventually stopped within 1.5 h, as in previous reports. However, the subsequent addition of toluene, which is the principal substrate of TDO, resulted in its immediate degradation without a lag phase. After the consumption of toluene, degradation of TCE restarted at a rate similar to its initial degradation, suggesting that this degradation was mediated by TDO molecules that were present before the cessation of TCE degradation. The addition of benzene and cumene, which are also substrates of TDO, also caused restoration of TCE degradation activity: TCE was degraded simultaneously with cumene, and a larger amount of TCE was degraded after cumene was added than after toluene or benzene was added. But substrates that were expected to supply the cells with NADH or energy did not restore TCE degradation activity. This cycle of pseudoinactivation and restoration of TCE degradation was observed repeatedly without a significant decrease in the number of viable cells, even after six additions of toluene spread over 30 h. The results obtained in this study demonstrate a new type of restoration of TCE degradation that has not been previously reported. PMID:15128539

  8. Simultaneous biodegradation of carbon tetrachloride and trichloroethylene in a coupled anaerobic/aerobic biobarrier.

    PubMed

    Kwon, Kiwook; Shim, Hojae; Bae, Wookeun; Oh, Juhyun; Bae, Jisu

    2016-08-01

    Simultaneous biodegradation of carbon tetrachloride (CT) and trichloroethylene (TCE) in a biobarrier with polyethylene glycol (PEG) carriers was studied. Toluene/methanol and hydrogen peroxide (H2O2) were used as electron donors and an electron acceptor source, respectively, in order to develop a biologically active zone. The average removal efficiencies for TCE and toluene were over 99.3%, leaving the respective residual concentrations of ∼12 and ∼57μg/L, which are below or close to the groundwater quality standards. The removal efficiency for CT was ∼98.1%, with its residual concentration (65.8μg/L) slightly over the standards. TCE was aerobically cometabolized with toluene as substrate while CT was anaerobically dechlorinated in the presence of electron donors, with the respective stoichiometric amount of chloride released. The oxygen supply at equivalent to 50% chemical oxygen demand of the injected electron donors supported successful toluene oxidation and also allowed local anaerobic environments for CT reduction. The originally augmented (immobilized in PEG carriers) aerobic microbes were gradually outcompeted in obtaining substrate and oxygen. Instead, newly developed biofilms originated from indigenous microbes in soil adapted to the coupled anaerobic/aerobic environment in the carrier for the simultaneous and almost complete removal of CT, TCE, and toluene. The declined removal rates when temperature fell from 28 to 18°C were recovered by doubling the retention time (7.2 days). PMID:27054665

  9. DECHLORINATION OF TRICHLOROETHYLENE USING ELECTROCHEMICAL METHODS

    EPA Science Inventory

    Electrochemical degradation (ECD) is used to decontaminate organic and inorganic contaminants through oxidative or reductive processes. The ECD of Trichloroethylene (TCE) dechlorinates TCE through electric reduction. TCE dechlorination presented in the literature utilized electro...

  10. 21 CFR 173.290 - Trichloroethylene.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... trichloroethylene resulting from its use as a solvent in the manufacture of foods as follows: Decaffeinated ground coffee 25 parts per million. Decaffeinated soluble (instant) coffee extract 10 parts per million....

  11. Continuous Determination of High-Vapor Phase Concentrations of Tetrachloroethylene Using On-Line Mass Spectrometry

    EPA Science Inventory

    A method was developed to determine the vapor concentration of tetrachloroethylene (PCE) at and below its equilibrium vapor phase concentration, 168,000 μg/L (25°C). Vapor samples were drawn by vacuum into a six-port sampling valve and injected through a jet separator into an io...

  12. 40 CFR 721.3560 - Derivative of tetra-chloro-ethy-lene.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Health Administration regulations and set forth at 29 CFR 1910.134, and 30 CFR part 11, respectively, and... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Derivative of tetra-chloro-ethy-lene. 721.3560 Section 721.3560 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)...

  13. 40 CFR 721.3560 - Derivative of tetra-chloro-ethy-lene.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Derivative of tetra-chloro-ethy-lene. 721.3560 Section 721.3560 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.3560 Derivative...

  14. 40 CFR 721.3560 - Derivative of tetra-chloro-ethy-lene.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Health Administration regulations and set forth at 29 CFR 1910.134, and 30 CFR part 11, respectively, and... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Derivative of tetra-chloro-ethy-lene. 721.3560 Section 721.3560 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)...

  15. 40 CFR 721.3560 - Derivative of tetra-chloro-ethy-lene.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Health Administration regulations and set forth at 29 CFR 1910.134, and 30 CFR part 11, respectively, and... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Derivative of tetra-chloro-ethy-lene. 721.3560 Section 721.3560 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)...

  16. 40 CFR 721.3560 - Derivative of tetra-chloro-ethy-lene.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Derivative of tetra-chloro-ethy-lene. 721.3560 Section 721.3560 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.3560 Derivative...

  17. EVALUATION OF GEOPHYSICAL METHODS FOR THE DETECTION OF SUBSURFACE TETRACHLOROETHYLENE (PCE) IN CONTROLLED SPILL EXPERIMENTS

    EPA Science Inventory

    Tetrachloroethylene (PCE), typically used as a dry cleaning solvent, is a predominant contaminant in the subsurface at Superfund Sites. PCE is a dense non-aqueous phase liquid (DNAPL) that migrates downward into the earth, leaving behind areas of residual saturation and free prod...

  18. Mortality of aerospace workers exposed to trichloroethylene.

    PubMed

    Morgan, R W; Kelsh, M A; Zhao, K; Heringer, S

    1998-07-01

    We measured mortality rates in a cohort of 20,508 aerospace workers who were followed up over the period 1950-1993. A total of 4,733 workers had occupational exposure to trichloroethylene. In addition, trichloroethylene was present in some of the washing and drinking water used at the work site. We developed a job-exposure matrix to classify all jobs by trichloroethylene exposure levels into four categories ranging from "none" to "high" exposure. We calculated standardized mortality ratios for the entire cohort and the trichloroethylene exposed subcohort. In the standardized mortality ratio analyses, we observed a consistent elevation for nonmalignant respiratory disease, which we attribute primarily to the higher background rates of respiratory disease in this region. We also compared trichloroethylene-exposed workers with workers in the "low" and "none" exposure categories. Mortality rate ratios for nonmalignant respiratory disease were near or less than 1.00 for trichloroethylene exposure groups. We observed elevated rare ratios for ovarian cancer among those with peak exposure at medium and high levels] relative risk (RR) = 2.74; 95% confidence interval (CI) = 0.84-8.99] and among women with high cumulative exposure (RR = 7.09; 95% CI = 2.14-23.54). Among those with peak exposures at medium and high levels, we observed slightly elevated rate ratios for cancers of the kidney (RR = 1.89; 95% CI = 0.85-4.23), bladder (RR = 1.41; 95% CI = 0.52-3.81), and prostate (RR = 1.47; 95% CI = 0.85-2.55). Our findings do not indicate an association between trichloroethylene exposure and respiratory cancer, liver cancer, leukemia or lymphoma, or all cancers combined. PMID:9647907

  19. Trichloroethylene interactions with muscle cells.

    PubMed

    Kössler, F

    1991-06-01

    The toxic effect of trichlorethylene (TCE) was investigated on isolated muscles prepared from frog and rats. Twitch and tetanic contractions as well as caffeine-induced contractures, were recorded. Trichloroethylene at a concentration of 0.25-4.0 mM depressed the force development of both twitch and tetanic tension in a dose-dependent manner. This effect was not influenced by the type of muscle. As TCE shortened the time to peak of twitch contractions, it may alter the Ca2+ binding kinetics. Subthreshold caffeine concentrations applied after pre-exposure to TCE (1 or 2mM) induced contractures. The same TCE exposure enhanced regular caffeine contractures through increasing the speed of tension development and the absolute force. Exposure to 5 or 10 mM TCE did not affect the first caffeine-induced contracture but enhanced the potency of the second caffeine dose given 15 min after the first. The results suggest that the interaction of TCE with membrane sites is responsible for Ca2+ release for contractile processes. PMID:1918792

  20. Test Pile Reactivity Loss Due to Trichloroethylene

    SciTech Connect

    Plumlee, K.E.

    2001-03-09

    The presence of trichloroethylene in the test pile caused a continual decrease in pile reactivity. A system which removed, purified, and returned 12,000 cfh helium to the pile has held contamination to a negligible level and has permitted normal pile operation.

  1. 21 CFR 173.290 - Trichloroethylene.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Trichloroethylene. 173.290 Section 173.290 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SECONDARY DIRECT FOOD ADDITIVES PERMITTED IN FOOD FOR HUMAN CONSUMPTION Solvents, Lubricants, Release Agents and...

  2. 21 CFR 173.290 - Trichloroethylene.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Trichloroethylene. 173.290 Section 173.290 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) SECONDARY DIRECT FOOD ADDITIVES PERMITTED IN FOOD FOR HUMAN CONSUMPTION Solvents, Lubricants, Release Agents and...

  3. Silylene- and disilyleneacetylene polymers from trichloroethylene

    DOEpatents

    Barton, T.J.; Ijadi-Maghsoodi, S.

    1990-07-10

    Organosilane polymers having recurring silyleneacetylene and/or disilyleneacetylene units are prepared in a one-pot synthesis from trichloroethylene. Depending on the organic substituents (R and R[prime]), these polymers have useful film-forming properties, and are converted to the ceramic, silicon carbide upon heating in very uniform high yields. They can also be pulled into fibers.

  4. Silylene- and disilyleneacetylene polymers from trichloroethylene

    DOEpatents

    Barton, Thomas J.; Ijadi-Maghsoodi, Sina

    1990-07-10

    Organosilane polymers having recurring silyleneacetylene and/or disilyleneacetylene units are prepared in a one-pot synthesis from trichloroethylene. Depending on the organic substituents (R and R'), these polymers have useful film-forming properties, and are converted to the ceramic, silicon carbide upon heating in very uniform high yields. They can also be pulled into fibers.

  5. Induction of toluene oxidation activity in pseudomonas mendocina KR1 and pseudomonas sp. strain ENVPC5 by chlorinated solvents and alkanes

    SciTech Connect

    McClay, K.; Streger, S.H.; Steffan, R.J.

    1995-09-01

    Toluene oxidation activity in Pseudomonas mendocina KR1 and Pseudomonas sp. strain ENVPC5 was induced by trichloroethylene (TCE), and induction was followed by the degradation of TCE. Higher levels of toluene oxidation activity were achieved in the presence of a supplemental growth substrate such as glutamate, with levels of activity of up to 86% of that observed with toluene-induced cells. Activity in P. mendocina KR1 was also induced by cis-1,2-dichloroethylene, perchloroethylene, chloroethane, hexane, pentane, and octane, but not by trans-1,2-dichloroethylene. Toluene oxidation was not induced by TCE in Burkholderia (Pseudomonas) cepacia G4, P. putida F1, Pseudomonas sp. strain ENV110, or Pseudomonas sp. strain ENV113. 22 refs., 4 tabs.

  6. KINETICS OF TRICHLOROETHYLENE COMETABOLISM AND TOLUENE BIODEGRADATION: MODEL APPLICATION TO SOIL BATCH EXPERIMENTS. (R825433)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  7. Abatement of trichloroethylene using DBD plasma

    NASA Astrophysics Data System (ADS)

    Vesali-Naseh, M.; Xu, S.; Xu, L.; Khodadadi, A.; Mortazavi, Y.; Ostrikov, K.

    2014-08-01

    Dielectric barrier discharge plasma was used to oxidize trichloroethylene (TCE) in 21% of O2 in carriers of N2 and He. The degradation products of TCE were analyzed using gas chromatography mass spectrometry. TCE was decomposed completely at optimum energy density of 260 and 300 J/l for He and N2, respectively and its conversion followed zero order reaction. The TCE removal efficiency is decreased in humid air due to interception of reactive intermediates by OH radicals.

  8. Leaching of toluene-neoprene adhesive wastes.

    PubMed

    Font, R; Sabater, M C; Martínez, M A

    2001-03-01

    This work consists of the study of the extraction of solvent (toluene) from a polymeric (neoprene) substrate during a leaching process. Total organic carbon (TOC) is the main contaminant parameter in the leaching of these systems due to the solution of the toluene and the dispersion of the polymer. The toxicity of the extracts was measured with a Microtox equipment, using Photobacteria phosphoreum, deducing that the toxicity of the extracts is low due to the low solubility of toluene but that the toxicity of toluene is high. On the basis of the experimental results, the amount of toluene diffused vs time in plane sheet systems was studied. A kinetic model has been developed considering two stages: In the first stage, the toluene diffuses into the system across the neoprene chains at a constant rate, not depending on the initial toluene concentration. This fact is explained by considering that there is a constant difference of the toluene concentration between the interface with the water and the inner part of the sample. In the second stage, the dispersion of the polymer with the corresponding amount of toluene takes place. The diffusion of toluene in the leaching process is compared and analyzed considering the diffusion of toluene in a desorption process in air so that the difference of toluene concentration between the interface and the interior can be estimated. A mathematical model is also proposed for considering the leaching process in other operating conditions. PMID:11351545

  9. Pulmonary reactions caused by welding-induced decomposed trichloroethylene

    SciTech Connect

    Sjoegren, B.P.; Plato, N.; Alexandersson, R.; Eklund, A.; Falkenberg, C. )

    1991-01-01

    This is the report of a welder who performed argon-shielded electric arc welding in an atmosphere containing trichloroethylene. He developed immediate respiratory symptoms, pulmonary edema 12 hours after exposure, and recurring dyspnea ten days after exposure. These pulmonary reactions might be explained by inhalation of decomposition products of trichloroethylene such as dichloroacetyl chloride and phosgene.

  10. Inhibited 1,1,1-trichloroethane replaces trichloroethylene for degreasing

    NASA Technical Reports Server (NTRS)

    Schuler, F. T.

    1970-01-01

    In fight against air pollution inhibited TCE /1,1,1-trichloroethane/ is effective substitute for trichloroethylene in degreasing plants. This chemical has only slight photochemical activity and causes little eye irritation. TCE is less toxic than trichloroethylene and can withstand production loads and conditions, or long term storage, without degradation.

  11. Toluene stability Space Station Rankine power system

    NASA Technical Reports Server (NTRS)

    Havens, V. N.; Ragaller, D. R.; Sibert, L.; Miller, D.

    1987-01-01

    A dynamic test loop is designed to evaluate the thermal stability of an organic Rankine cycle working fluid, toluene, for potential application to the Space Station power conversion unit. Samples of the noncondensible gases and the liquid toluene were taken periodically during the 3410 hour test at 750 F peak temperature. The results obtained from the toluene stability loop verify that toluene degradation will not lead to a loss of performance over the 30-year Space Station mission life requirement. The identity of the degradation products and the low rates of formation were as expected from toluene capsule test data.

  12. Alkylation of toluene with ethanol

    SciTech Connect

    Walendziewski, J.; Trawczynski, J.

    1996-10-01

    A series of Y and ZSM-5 zeolite based catalysts was prepared. Zeolites were cation exchanged and formed with 50% of aluminum hydroxide as a binder, and the obtained catalysts were finally thermally treated. Activity tests in alkylation of toluene with ethanol were carried out in the temperature range of 325--400 C, in nitrogen or hydrogen stream, and a pressure up to 3 MPa. The feed consisted of toluene and ethanol mixed in a mole ratio 1/1 or 2/1. The obtained results showed that among the studied catalysts the highest activity in the alkylation reaction was attained by ZSM-5 zeolite based catalyst with a moderate acidity and medium silica to alumina ratio, i.e., {approximately}50. Activity and selectivity of the most active catalyst as well as conversion of the feed components were similar to those reported in other papers. The content of p-ethyltoluene in alkylation products attained ca. 60%.

  13. Characterization of the methanotrophic bacterial community present in a trichloroethylene-contaminated subsurface groundwater site.

    PubMed Central

    Bowman, J P; Jiménez, L; Rosario, I; Hazen, T C; Sayler, G S

    1993-01-01

    Groundwater, contaminated with trichloroethylene (TCE) and tetrachloroethylene (PCE), was collected from 13 monitoring wells at Area M on the U.S. Department of Energy Savannah River Site near Aiken, S.C. Filtered groundwater samples were enriched with methane, leading to the isolation of 25 methanotrophic isolates. The phospholipid fatty acid profiles of all the isolates were dominated by 18:1 omega 8c (60 to 80%), a signature lipid for group II methanotrophs. Subsequent phenotypic testing showed that most of the strains were members of the genus Methylosinus and one isolate was a member of the genus Methylocystis. Most of the methanotroph isolates exhibited soluble methane monooxygenase (sMMO) activity. This was presumptively indicated by the naphthalene oxidation assay and confirmed by hybridization with a gene probe encoding the mmoB gene and by cell extract assays. TCE was degraded at various rates by most of the sMMO-producing isolates, whereas PCE was not degraded. Savannah River Area M and other groundwaters, pristine and polluted, were found to support sMMO activity when supplemented with nutrients and then inoculated with Methylosinus trichosporium OB3b. The maximal sMMO-specific activity obtained in the various groundwaters ranged from 41 to 67% compared with maximal rates obtained in copper-free nitrate mineral salts media. This study partially supports the hypothesis that stimulation of indigenous methanotrophic communities can be efficacious for removal of chlorinated aliphatic hydrocarbons from subsurface sites and that the removal can be mediated by sMMO. PMID:8368829

  14. Acute toxicity of trichloroethylene to saltwater organisms

    SciTech Connect

    Ward, G.S.; Tolmsoff, A.J.; Petrocelli, S.R.

    1986-12-01

    Trichloroethylene (TCE) is a chlorinated aliphatic hydrocarbon primarily utilized for vapor-phase degreasing in the fabricated metals industry. Other applications include cold-metal cleaning and use in the manufacture of organic chemicals. TCE enters the environment as a result of volatilization during its production and through its industrial uses. TCE has been detected in aquatic environments and organisms at part-per-trillion (pptr) concentrations. Although TCE is indicated to be widely distributed, relatively limited data exist on the acute effects of TCE on aquatic organisms, especially saltwater species. Results of static acute tests of TCE with a saltwater alga, invertebrate, and fish are reported here to enhance the data base.

  15. Mineralization of trichloroethylene by heterotrophic enrichment cultures

    SciTech Connect

    Phelps, T.J.; Ringelberg, D.; Mikell, A.T.; White, D.C. |; Fliermans, C.B.

    1988-12-31

    Microbial consortia capable of aerobically degrading greater than 99% of 50 mg/l exogenous trichloroethylene (TCE) have been enriched from TCE contaminated subsurface sediments. Concentrations of TCE greater than 300 mg/l were not degraded nor was TCE used as a sole energy source. Successful electron donors for growth included tryptone-yeast extract, methanol, methane or propane. The optimum temperature for growth was 22--37 C and the ph optimum was 7.0--8.1. Utilization of TCE occurred only after apparent microbial growth had ceased. The major end products recovered were hydrochloric acid and carbon dioxide. Minor products included dichloroethylene, vinylidine chloride and possibly chloroform.

  16. SURFACTANT ENHANCED RECOVERY OF TETRACHLOROETHYLENE FROM A POROUS MEDIUM CONTAINING LOW PERMEABILITY LENSES. 1. EXPERIMENTAL STUDIES. (R825409)

    EPA Science Inventory

    Abstract

    A matrix of batch, column and two-dimensional (2-D) box experiments was conducted to investigate the coupled effects of rate-limited solubilization and layering on the entrapment and subsequent recovery of a representative dense NAPL, tetrachloroethylene (PCE)...

  17. Fogging in Polyvinyl Toluene Scintillators

    SciTech Connect

    Cameron, Richard J.; Fritz, Brad G.; Hurlbut, Charles; Kouzes, Richard T.; Ramey, Ashley; Smola, Richard

    2015-02-01

    It has been observed that large polyvinyl toluene (PVT)-based gamma ray detectors can suffer internal “fogging” when exposed to outdoor environmental conditions over long periods of time. When observed, this change results in reduced light collection by photomultiplier tubes connected to the PVT. Investigation of the physical cause of these changes has been explored, and a root cause identified. Water penetration into the PVT from hot, high-humidity conditions results in reversible internal water condensation at room temperature, and permanent micro-fracturing of the PVT at very low environmental temperatures. Mitigation procedures and methods are being investigated.

  18. IRIS Toxicological Review of Trichloroethylene (Interagency Science Discussion Draft)

    EPA Science Inventory

    EPA is releasing the draft report, Toxicological Review of Trichloroethylene, that was distributed to Federal agencies and White House Offices for comment during the Science Discussion step of the IRIS Assessment Development Process. Comments received from other Federal agencies ...

  19. EVALUATION OF MULTIPLE PHARMACOKINETIC MODELING STRUCTURES FOR TRICHLOROETHYLENE

    EPA Science Inventory

    A series of PBPK models were developed for trichloroethylene (TCE) to evaluate biological processes that may affect the absorption, distribution, metabolism and excretion (ADME) of TCE and its metabolites.

  20. IRIS Toxicological Review of Trichloroethylene (TCE) (External Review Draft)

    EPA Science Inventory

    EPA is conducting a peer review and public comment of the scientific basis supporting the human health hazard and dose-response assessment of Trichloroethylene (TCE) that when finalized will appear on the Integrated Risk Information System (IRIS) database.

  1. Evaluation of toxicity of trichloroethylene for plants

    SciTech Connect

    Ryu, S.B.; Davis, L.C.; Dana, J.; Selk, K.; Erickson, L.E.

    1996-12-31

    Trichloroethylene (TCE) exposure of several species of plants was studied. Although earlier studies indicated that the root systems of plants could tolerate an aqueous phase concentration of 1 mM for a day, toxicity to whole plants was observed at somewhat lower levels in the gas phase in this study. The tested species included pumpkin (Cucurbita maxima), tomato (Lycopersicon esculentum), sweet potato (Dioscoria batata), tobacco (Nicotiana tabacum), soybean (Glycine max L. Merr), and alfalfa (Medicago sativa). Damage was observable as wilting or failure of the gravitropic response of shoots at levels above about 0.2 mM in the gas phase, which corresponds to 0.5 mM in the aqueous phase. Plants were usually killed quickly at gas phase concentrations above 0.4 mM.

  2. 27 CFR 21.132 - Toluene.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Toluene. 21.132 Section 21.132 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL FORMULAS FOR DENATURED ALCOHOL AND RUM Specifications for Denaturants § 21.132 Toluene. (a) Distillation range. (For...

  3. HEALTH EFFECTS OF TOLUENE: A REVIEW

    EPA Science Inventory

    This evaluative review covers the neurotoxic effects of toluene. General health effects of toluene are also discussed in more limited detail. A brief description of chemical properties and environmental prevalence is given, followed by a review of pharmacokinetic data. General he...

  4. 27 CFR 21.132 - Toluene.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Toluene. 21.132 Section 21.132 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS FORMULAS FOR DENATURED ALCOHOL AND RUM Specifications for Denaturants § 21.132 Toluene. (a) Distillation range. (For...

  5. 27 CFR 21.132 - Toluene.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Toluene. 21.132 Section 21.132 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS FORMULAS FOR DENATURED ALCOHOL AND RUM Specifications for Denaturants § 21.132 Toluene. (a) Distillation range. (For...

  6. 27 CFR 21.132 - Toluene.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Toluene. 21.132 Section 21.132 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL FORMULAS FOR DENATURED ALCOHOL AND RUM Specifications for Denaturants § 21.132 Toluene. (a) Distillation range. (For...

  7. Ethnic Differences in the Metabolism of Toluene: Comparisons between Korean and Foreign Workers Exposed to Toluene

    PubMed Central

    Won, Young Lim; Ko, Kyung Sun

    2015-01-01

    The objectives of this study were to investigate the individual characteristics, lifestyle habits, exposure levels, and genetic diversity of xenobiotic-metabolizing enzymes involved in toluene metabolism in Korean and foreign workers exposed to toluene at a manufacturing plant. This study was conducted to determine the effects of culture or ethnicity on toluene metabolism. The results showed that blood and urinary toluene concentrations were dependent on the level of exposure to toluene. We analyzed the correlation between toluene metabolism and genetic diversity in glutathione S-transferase (GST) (M1), GSTT1, and cytochrome p-450 (CYP) 2E1*5 as well as lifestyle habits (smoking, drinking, and exercise habits). The results revealed significant correlations between toluene metabolism and GSTM1 and GSTT1 genetic diversity, as well as smoking and exercise. PMID:25874030

  8. TETRACHLOROETHYLENE EXPOSURE AND RISK OF SCHIZOPHRENIA: OFFSPRING OF DRY CLEANERS IN A POPULATION BIRTH COHORT, PRELIMINARY FINDINGS

    PubMed Central

    Perrin, Mary C.; Opler, Mark G.; Harlap, Susan; Harkavy-Friedman, Jill; Kleinhaus, Karine; Nahon, Daniella; Fennig, Shmuel; Susser, Ezra S.; Malaspina, Dolores

    2009-01-01

    Tetrachloroethylene is a solvent used in dry cleaning with reported neurotoxic effects. Using proportional hazard methods, we examined the relationship between parental occupation as a dry cleaner and risk for schizophrenia in a prospective population-based cohort of 88, 829 offspring born in Jerusalem from 1964 through 1976, followed from birth to age 21–33 years. Of 144 offspring whose parents were dry cleaners, 4 developed schizophrenia. We observed an increased incidence of schizophrenia in offspring of parents who were dry cleaners (RR = 3.4, 95% CI, 1.3–9.2, p=0.01). Tetrachloroethylene exposure warrants further investigation as a risk factor for schizophrenia. PMID:17113267

  9. Integrating Address Geocoding, Land Use Regression, and Spatiotemporal Geostatistical Estimation for Groundwater Tetrachloroethylene

    PubMed Central

    Messier, Kyle P.; Akita, Yasuyuki; Serre, Marc L.

    2012-01-01

    Geographic Information Systems (GIS) based techniques are cost-effective and efficient methods used by state agencies and epidemiology researchers for estimating concentration and exposure. However, budget limitations have made statewide assessments of contamination difficult, especially in groundwater media. Many studies have implemented address geocoding, land use regression, and geostatistics independently, but this is the first to examine the benefits of integrating these GIS techniques to address the need of statewide exposure assessments. A novel framework for concentration exposure is introduced that integrates address geocoding, land use regression (LUR), below detect data modeling, and Bayesian Maximum Entropy (BME). A LUR model was developed for Tetrachloroethylene that accounts for point sources and flow direction. We then integrate the LUR model into the BME method as a mean trend while also modeling below detects data as a truncated Gaussian probability distribution function. We increase available PCE data 4.7 times from previously available databases through multistage geocoding. The LUR model shows significant influence of dry cleaners at short ranges. The integration of the LUR model as mean trend in BME results in a 7.5% decrease in cross validation mean square error compared to BME with a constant mean trend. PMID:22264162

  10. Adult Neuropsychological Performance Following Prenatal and Early Postnatal Exposure to Tetrachloroethylene (PCE)-contaminated Drinking Water

    PubMed Central

    Janulewicz, Patricia A; White, Roberta F; Martin, Brett M; Winter, Michael R; Weinberg, Janice M; Vieira, Veronica; Aschengrau, Ann

    2012-01-01

    This population-based retrospective cohort study examined adult performance on a battery of neuropsychological tests in relation to prenatal and early postnatal exposure to tetrachloroethylene (PCE)-contaminated drinking water on Cape Cod, Massachusetts. Subjects were identified through birth records from 1969 through 1983. Exposure was modeled using pipe network information from town water departments, a PCE leaching and transport algorithm, EPANet water flow modeling software, and a Geographic Information System (GIS). Results of crude and multivariate analyses among 35 exposed and 28 unexposed subjects showed no association between prenatal and early postnatal exposure and decrements on tests that assess abilities in the domains of omnibus intelligence, academic achievement or language. The results were suggestive of an association between prenatal and early postnatal PCE exposure and diminished performance on tests that assessed abilities in the domains of visuospatial functioning, learning and memory, motor, attention and mood. Because the sample size was small, most findings were not statistically significant. Future studies with larger sample sizes should be conducted to further define the neuropsychological consequences of early developmental PCE exposure. PMID:22522125

  11. Integrating address geocoding, land use regression, and spatiotemporal geostatistical estimation for groundwater tetrachloroethylene.

    PubMed

    Messier, Kyle P; Akita, Yasuyuki; Serre, Marc L

    2012-03-01

    Geographic information systems (GIS) based techniques are cost-effective and efficient methods used by state agencies and epidemiology researchers for estimating concentration and exposure. However, budget limitations have made statewide assessments of contamination difficult, especially in groundwater media. Many studies have implemented address geocoding, land use regression, and geostatistics independently, but this is the first to examine the benefits of integrating these GIS techniques to address the need of statewide exposure assessments. A novel framework for concentration exposure is introduced that integrates address geocoding, land use regression (LUR), below detect data modeling, and Bayesian Maximum Entropy (BME). A LUR model was developed for tetrachloroethylene that accounts for point sources and flow direction. We then integrate the LUR model into the BME method as a mean trend while also modeling below detects data as a truncated Gaussian probability distribution function. We increase available PCE data 4.7 times from previously available databases through multistage geocoding. The LUR model shows significant influence of dry cleaners at short ranges. The integration of the LUR model as mean trend in BME results in a 7.5% decrease in cross validation mean square error compared to BME with a constant mean trend. PMID:22264162

  12. Composition of toluene-degrading microbial communities from soil at different concentrations of toluene.

    PubMed

    Hubert, C; Shen, Y; Voordouw, G

    1999-07-01

    Toluene-degrading bacteria were isolated from hydrocarbon-contaminated soil by incubating liquid enrichment cultures and agar plate cultures in desiccators in which the vapor pressure of toluene was controlled by dilution with vacuum pump oil. Incubation in desiccators equilibrated with either 100, 10, or 1% (wt/wt) toluene in vacuum pump oil and testing for genomic cross-hybridization resulted in four genomically distinct strains (standards) capable of growth on toluene (strains Cstd1, Cstd2, Cstd5, and Cstd7). The optimal toluene concentrations for growth of these standards on plating media differed considerably. Cstd1 grew best in an atmosphere equilibrated with 0.1% (wt/wt) toluene, but Cstd5 failed to grow in this atmosphere. Conversely, Cstd5 grew well in the presence of 10% (wt/wt) toluene, which inhibited growth of Cstd1. 16S ribosomal DNA sequencing and cross-hybridization analysis indicated that both Cstd1 and Cstd5 are members of the genus Pseudomonas. An analysis of the microbial communities in soil samples that were incubated with 10% (wt/wt) toluene with reverse sample genome probing indicated that Pseudomonas strain Cstd5 was the dominant community member. However, incubation of soil samples with 0.1% (wt/wt) toluene resulted in a community that was dominated by Pseudomonas strain Q7, a toluene degrader that has been described previously (Y. Shen, L. G. Stehmeier, and G. Voordouw, Appl. Environ. Microbiol. 64:637-645, 1998). Q7 was not able to grow by itself in an atmosphere equilibrated with 0.1% (wt/wt) toluene but grew efficiently in coculture with Cstd1, suggesting that toluene or metabolic derivatives of toluene were transferred from Cstd1 to Q7. PMID:10388704

  13. Composition of Toluene-Degrading Microbial Communities from Soil at Different Concentrations of Toluene

    PubMed Central

    Hubert, Casey; Shen, Yin; Voordouw, Gerrit

    1999-01-01

    Toluene-degrading bacteria were isolated from hydrocarbon-contaminated soil by incubating liquid enrichment cultures and agar plate cultures in desiccators in which the vapor pressure of toluene was controlled by dilution with vacuum pump oil. Incubation in desiccators equilibrated with either 100, 10, or 1% (wt/wt) toluene in vacuum pump oil and testing for genomic cross-hybridization resulted in four genomically distinct strains (standards) capable of growth on toluene (strains Cstd1, Cstd2, Cstd5, and Cstd7). The optimal toluene concentrations for growth of these standards on plating media differed considerably. Cstd1 grew best in an atmosphere equilibrated with 0.1% (wt/wt) toluene, but Cstd5 failed to grow in this atmosphere. Conversely, Cstd5 grew well in the presence of 10% (wt/wt) toluene, which inhibited growth of Cstd1. 16S ribosomal DNA sequencing and cross-hybridization analysis indicated that both Cstd1 and Cstd5 are members of the genus Pseudomonas. An analysis of the microbial communities in soil samples that were incubated with 10% (wt/wt) toluene with reverse sample genome probing indicated that Pseudomonas strain Cstd5 was the dominant community member. However, incubation of soil samples with 0.1% (wt/wt) toluene resulted in a community that was dominated by Pseudomonas strain Q7, a toluene degrader that has been described previously (Y. Shen, L. G. Stehmeier, and G. Voordouw, Appl. Environ. Microbiol. 64:637–645, 1998). Q7 was not able to grow by itself in an atmosphere equilibrated with 0.1% (wt/wt) toluene but grew efficiently in coculture with Cstd1, suggesting that toluene or metabolic derivatives of toluene were transferred from Cstd1 to Q7. PMID:10388704

  14. Anticonvulsant and antipunishment effects of toluene

    SciTech Connect

    Wood, R.W.; Coleman, J.B.; Schuler, R.; Cox, C.

    1984-01-01

    Toluene can have striking acute behavioral effects and is subject to abuse by inhalation. To determine if its actions resemble those of drugs used in the treatment of anxiety (anxiolytics), two sets of experiments were undertaken. Inasmuch as prevention of pentylenetetrazol-induced convulsions is an identifying property of this class of agents, the authors first demonstrated that pretreatment of mice with injections of toluene delayed the onset of convulsive signs and prevented the tonic extension phase of the convulsant activity in a dose-related manner. Injections of another alkyl benzene, m-xylene, were of comparable potency to toluene. Inhalation of toluene delayed the time of death after pentylenetetrazol injection in a manner related to the duration and concentration of exposure; at lower convulsant doses, inhalation of moderate concentrations (EC/sub 58/, 1300 ppm) prevented death. Treatment with a benzodiazepine receptor antagonist (Ro 15-1788) failed to reduce the anticonvulsant activity of inhaled toluene. Anxiolytics also attenuate the reduction in response rate produced by punishment with electric shock. Toluene increased rates of responding suppressed by punishment when responding was maintained under a multiple fixed-interval fixed-interval punishment schedule of reinforcement. Distinct antipunishment effects were observed in rats after 2 hr of exposure to 1780 and 3000 ppm of toluene; the rate-increasing effects of toluene were related to concentration and to time after the termination of exposure. Thus, toluene and m-xylene resemble in several respects clinically useful drugs such as the benzodiazepines. 51 references, 3 figures, 2 tables.

  15. 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).

  16. Dilated cardiomyopathy associated with toluene abuse.

    PubMed

    Vural, Mutlu; Ogel, Kultegin

    2006-01-01

    The use of paint thinner and glue to achieve an euphoric state has been associated with serious social and health problems in children and young adults. We present the case of a 21-year-old man with dilated cardiomyopathy occurring following abuse of paint thinner and glue containing toluene as main compound. After cessation of toluene abuse, the patient recovered rapidly and completely. Because of the increasing prevalence of toluene abuse, harmful effects of this volatile agent on the heart are also discussed. PMID:16479101

  17. 78 FR 34377 - Trichloroethylene TSCA Chemical Risk Assessment; Notice of Public Meetings and Opportunity to...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-07

    ... Risk Assessment for Trichloroethylene: Degreaser and Arts/Crafts Uses.'' EPA will hold three peer..., including one entitled, ``TSCA Workplan Chemical Risk Assessment for Trichloroethylene: Degreaser and Arts/Crafts Uses.'' Trichloroethylene (TCE) (CASRN 79-01-6) is one of 83 chemicals identified for review...

  18. Current trends in trichloroethylene biodegradation: a review.

    PubMed

    Shukla, Awadhesh Kumar; Upadhyay, Siddh Nath; Dubey, Suresh Kumar

    2014-06-01

    Over the past few years biodegradation of trichloroethylene (TCE) using different microorganisms has been investigated by several researchers. In this review article, an attempt has been made to present a critical summary of the recent results related to two major processes--reductive dechlorination and aerobic co-metabolism used for TCE biodegradation. It has been shown that mainly Clostridium sp. DC-1, KYT-1, Dehalobacter, Dehalococcoides, Desulfuromonas, Desulfitobacterium, Propionibacterium sp. HK-1, and Sulfurospirillum bacterial communities are responsible for the reductive dechlorination of TCE. Efficacy of bacterial communities like Nitrosomonas, Pseudomonas, Rhodococcus, and Xanthobacter sp. etc. for TCE biodegradation under aerobic conditions has also been examined. Mixed cultures of diazotrophs and methanotrophs have been used for TCE degradation in batch and continuous cultures (biofilter) under aerobic conditions. In addition, some fungi (Trametes versicolor, Phanerochaete chrysosporium ME-446) and Actinomycetes have also been used for aerobic biodegradation of TCE. The available information on kinetics of biofiltration of TCE and its degradation end-products such as CO2 are discussed along with the available results on the diversity of bacterial community obtained using molecular biological approaches. It has emerged that there is a need to use metabolic engineering and molecular biological tools more intensively to improve the robustness of TCE degrading microbial species and assess their diversity. PMID:23057686

  19. Emission factors for trichloroethylene vapor degreasers

    SciTech Connect

    Wadden, R.A.; Scheff, P.A.; Franke, J.E. )

    1989-09-01

    Emission factors were developed for two production trichloroethylene (TCE) vapor degreasers: an open-top (0.76 m x 1.16 m x 1.8 m) and a conveyor-fed enclosed design. Both were fitted with functioning local exhaust hoods. Emissions were determined from field data by using a Fick's law diffusion approach and the observed variation in time of the TCE concentration gradient within 4 m of each device. The average emission factor for the open-top degreaser was 2.6 g TCE/min (2.9 g TCE/(m2.min)) which corresponds to 9.5% of the total degreaser emissions escaping into the workplace. The average emission factor for the enclosed degreaser was 0.67 g TCE/min, a release of 3% of the total emissions into the work area. These values are considered to be representative of the average lower limit of emissions during production from TCE degreasers of like designs with similar local exhaust controls (which were typical but did not meet American Conference of Governmental Industrial Hygienists' (ACGIH) airflow rate criteria).

  20. Phytoremediation of trichloroethylene with hybrid poplars.

    PubMed

    Gordon, M; Choe, N; Duffy, J; Ekuan, G; Heilman, P; Muiznieks, I; Ruszaj, M; Shurtleff, B B; Strand, S; Wilmoth, J; Newman, L A

    1998-08-01

    Axenic tumor cultures of poplar cells, clone H11-11, were grown in the presence of [14C]-trichloroethylene (TCE) (uniformly labeled). The cells were capable of metabolizing TCE to produce trichloroethanol, di- and trichloroacetic acid. Some of the carbon from TCE was found in insoluble, nonextractable cell residue, and small amounts were mineralized to [14C]CO2. Poplar cuttings grown in soil and exposed to TCE produced the same metabolites. In field trials, trees were planted in soil in test cells and exposed to TCE via underground water injection during the growing season. During the growing season, at least 95% of the TCE was removed from the influent water stream in cells containing trees. Mass balance studies conducted in the laboratory indicated that 70 to 90% of the TCE was transpired; however, greenhouse and field study results showed that less than 5% of the total TCE taken up by the plants is transpired. These results show that significant TCE uptake and degradation occur in poplars. Poplars appear to be useful for in situ remediation of TCE-contaminated sites under proper conditions. PMID:9703485

  1. Human variability and susceptibility to trichloroethylene.

    PubMed Central

    Pastino, G M; Yap, W Y; Carroquino, M

    2000-01-01

    Although humans vary in their response to chemicals, comprehensive measures of susceptibility have generally not been incorporated into human risk assessment. The U.S. EPA dose-response-based risk assessments for cancer and the RfD/RfC (reference dose-reference concentration) approach for noncancer risk assessments are assumed to protect vulnerable human subgroups. However, these approaches generally rely on default assumptions and do not consider the specific biological basis for potential susceptibility to a given toxicant. In an effort to focus more explicitly on this issue, this article addresses biological factors that may affect human variability and susceptibility to trichloroethylene (TCE), a widely used halogenated industrial solvent. In response to Executive Order 13045, which requires federal agencies to make protection of children a high priority in implementing their policies and to take special risks to children into account when developing standards, this article examines factors that may affect risk of exposure to TCE in children. The influence of genetics, sex, altered health state, coexposure to alcohol, and enzyme induction on TCE toxicity are also examined. PMID:10807552

  2. Polydispersity of asphaltenes in toluene

    SciTech Connect

    Sheu, E.Y.; Liang, K.S.; Sinha, S.K.; Overfield, R.E. )

    1990-08-01

    Asphaltenes have been reported to exhibit colloidal behavior in solutions. However, the thermodynamics of their self-association and the resulting particle polydispersity was not yet fully investigated. In this paper, the authors measured the structure and polydispersity of the asphaltene particles in toluene using small-angle neutron scattering (SANS). To study their self-association they systematically increased the solution temperature to observe the evolution, if any, of the particle structure and size. In order to determine the asphaltene size distribution and the corresponding polydispersity they fitted the SANS data with a polydispersity model in which one more adjustable parameter (than monodisperse analysis) was used to account for the particle size distribution. Because of one more free parameter used in data fitting, an ambiguous result due to multiple convergence may lead to a misinterpretation. In order to minimize this ambiguity and obtain a realistic particle size distribution they developed a method by which one can self-consistently verify the obtained particle size distribution. From SANS data analysis they found that the Schultz distribution function properly described the asphaltene particle sizes and the polydispersity decreases whenever temperature or concentration increases.

  3. 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.

  4. Primary atmospheric oxidation mechanism for toluene.

    PubMed

    Baltaretu, Cristian O; Lichtman, Eben I; Hadler, Amelia B; Elrod, Matthew J

    2009-01-01

    The products of the primary OH-initiated oxidation of toluene were investigated using the turbulent flow chemical ionization mass spectrometry technique at temperatures ranging from 228 to 298 K. A major dienedial-producing pathway was detected for the first time for toluene oxidation, and glyoxal and methylglyoxal were found to be minor primary oxidation products. The results suggest that secondary oxidation processes involving dienedial and epoxide primary products are likely responsible for previous observations of glyoxal and methylglyoxal products from toluene oxidation. Because the dienedial-producing pathway is a null cycle for tropospheric ozone production and glyoxal and methylglyoxal are important secondary organic aerosol precursors, these new findings have important implications for the modeling of toluene oxidation in the atmosphere. PMID:19118482

  5. Prenatal Exposure to Tetrachloroethylene-Contaminated Drinking Water and the Risk of Adverse Birth Outcomes

    PubMed Central

    Aschengrau, Ann; Weinberg, Janice; Rogers, Sarah; Gallagher, Lisa; Winter, Michael; Vieira, Veronica; Webster, Thomas; Ozonoff, David

    2008-01-01

    Background Prior studies of prenatal exposure to tetrachloroethylene (PCE) have shown mixed results regarding its effect on birth weight and gestational age. Objectives In this retrospective cohort study we examined whether PCE contamination of public drinking-water supplies in Massachusetts influenced the birth weight and gestational duration of children whose mothers were exposed before the child’s delivery. Methods The study included 1,353 children whose mothers were exposed to PCE-contaminated drinking water and a comparable group of 772 children of unexposed mothers. Birth records were used to identify subjects and provide information on the outcomes. Mothers completed a questionnaire to gather information on residential histories and confounding variables. PCE exposure was estimated using EPANET water distribution system modeling software that incorporated a fate and transport model. Results We found no meaningful associations between PCE exposure and birth weight or gestational duration. Compared with children whose mothers were unexposed during the year of the last menstrual period (LMP), adjusted mean differences in birth weight were 20.9, 6.2, 30.1, and 15.2 g for children whose mothers’ average monthly exposure during the LMP year ranged from the lowest to highest quartile. Similarly, compared with unexposed children, adjusted mean differences in gestational age were −0.2, 0.1, −0.1, and −0.2 weeks for children whose mothers’ average monthly exposure ranged from the lowest to highest quartile. Similar results were observed for two other measures of prenatal exposure. Conclusions These results suggest that prenatal PCE exposure does not have an adverse effect on these birth outcomes at the exposure levels experienced by this population. PMID:18560539

  6. Toluene-induced ototoxicity by subcutaneous administration

    SciTech Connect

    Pryor, G.T.; Howd, R.A.

    1986-01-01

    Inhalation exposure of rats to toluene causes irreversible hearing loss (e.g., Pryor et al.). To determine whether noise emanating from the inhalation system was a major contributing factor and whether exposure by a noninhalation route would cause a similar effect, weanling, male Fischer-344 rats were injected SC twice daily in a quiet environment with PEG-300 (control) or with 1.5 or 1.7 g/kg of toluene for 7 days. After being trained to perform a multisensory conditioned avoidance response (CAR) task, tone intensity-response functions were generated at 4, 8, 12, and 20 kHz, and behavioral auditory response thresholds were estimated. Toluene caused a dose-related hearing loss at frequencies of 8 kHz and above, with no effect on performance of the CAR in response to light, nonaversive footshock, or the 4-kHz tone. The similarity of this effect to that observed following inhalation exposure indicates that noise is not a major factor in the toluene-induced hearing loss, although possible interactions between noise and toluene remain to be investigated. These results also demonstrate that direct penetration of the toluene vapors through the external ear structure, as might occur during inhalation exposure, is not a necessary condition for inducing the hearing loss.

  7. 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.

  8. Biodegradation of trichloroethylene by Methylosinus trichosporium OB3b.

    PubMed Central

    Tsien, H C; Brusseau, G A; Hanson, R S; Waclett, L P

    1989-01-01

    The methanotroph Methylosinus trichosporium OB3b, a type II methanotroph, degraded trichloroethylene at rates exceeding 1.2 mmol/h per g (dry weight) following the appearance of soluble methane monooxygenase in continuous and batch cultures. Cells capable oxidizing trichloroethylene contained components of soluble methane monooxygenase as demonstrated by Western blot (immunoblot) analysis with antibodies prepared against the purified enzyme. Growth of cultures in a medium containing 0.25 microM or less copper sulfate caused derepression of the synthesis of soluble methane monooxygenase. In these cultures, the specific rates of methane and methanol oxidation did not change during growth, while trichloroethylene oxidation increased with the appearance of soluble methane monooxygenase. M. trichosporium OB3b cells that contained soluble methane monooxygenase also degraded vinyl chloride, 1,1-dichloroethylene, cis-1,2-dichloroethylene, and trans-1,2-dichloroethylene. Images PMID:2515801

  9. Human Health Risk Assessment of Trichloroethylene from Industrial Complex A

    PubMed Central

    Sin, Saemi

    2012-01-01

    This study investigated the human health risks of trichloroethylene from Industrial Complex A. The excessive carcinogenic risks for central tendency exposure were 1.40 × 10?5 for male and female residents in the vicinity of Industrial Complex A. The excessive cancers risk for reasonable maximum exposure were 2.88 × 10?5 and 1.97 × 10?5 for males and females, respectively. These values indicate that there are potential cancer risks for exposure to these concentrations. The hazard index for central tendency exposure to trichloroethylene was 1.71 for male and female residents. The hazard indexes for reasonable maximum exposure were 3.27 and 2.41 for males and females, respectively. These values were over one, which is equivalent to the threshold value. This result showed that adverse cancer and non-cancer health effects may occur and that some risk management of trichloroethylene from Industrial Complex A was needed. PMID:24278607

  10. Modeling of TCE and Toluene Toxicity to Pseudomonas putida F1

    NASA Astrophysics Data System (ADS)

    Singh, R.; Olson, M. S.

    2009-12-01

    Prediction of viable bacterial distribution with respect to contaminants is important for efficient bioremediation of contaminated ground-water aquifers, particularly those contaminated with residual NAPLs. While bacterial motility and chemotaxis may help situate bacteria close to high concentrations of contaminant thereby enhancing bioremediation, prolonged exposure to high concentrations of contaminates is toxic to contaminant-degrading bacteria. The purpose of this work is to model the toxicity of trichloroethylene and toluene to Pseudomonas putida F1. The Live/Dead® bacterial viability assay was used to determine the toxic effect of chemical contaminants on the viability of P. putida F1 in a sealed zero head-space experimental environment. Samples of bacterial suspensions were exposed to common ground-water pollutants, TCE and toluene, for different durations. Changes in live and dead cell populations were monitored over the course of experiments using fluorescence microscopy. Data obtained from these toxicity experiments were fit to simple linear and exponential bacterial decay models using non-linear regression to describe loss of bacterial viability. TCE toxicity to P. putida F1 was best described with an exponential decay model (Figure 1a), with a decay constant kTCE = 0.025 h-4.95 (r2 = 0.956). Toluene toxicity showed a marginally better fit to the linear decay model (Figure 1b) (r2 = 0.971), with a decay constant ktoluene = 0.204 h-1. Best-fit model parameters obtained for both TCE and toluene were used to predict bacterial viability in toxicity experiments with higher contaminant concentrations and matched well with experimental data. Results from this study can be used to predict bacterial accumulation and viability near NAPL sources, and thus may be helpful in improving bioremediation performance assessment of contaminated sites. Figure 1: Survival ratios (S = N/No) of P. putida F1 in TCE- (a) and toluene- (b) stressed samples (observed (

  11. Electrochemical fluorination of trichloroethylene and N, N-dimethyltrifluoroacetamide

    NASA Technical Reports Server (NTRS)

    Hsu, L.-C.

    1979-01-01

    The paper presents the results of experiments concerning the fluorination of trichloroethylene and N, N-dimethyltrifluoroacetamide carried out on a laboratory scale in an advanced 'Simons' type electrochemical apparatus which could be operated automatically from ambient to 50 psi pressure. It is shown that a variety of fluorine-substituted products are formed, depending upon electrolysis conditions and concentrations of reactant relative to the NaF, KF, HF electrolyte. A new reaction mechanism of electrochemical fluorination of trichloroethylene is proposed. Finally, the solvency-to-fluorine content relationship of fluorinated N, N-dimethyltrifluoroacetamide is described.

  12. Coexposure to Mercury Increases Immunotoxicity of Trichloroethylene

    PubMed Central

    Gilbert, Kathleen M.; Rowley, Benjamin; Gomez-Acevedo, Horacio; Blossom, Sarah J.

    2011-01-01

    We have shown previously that chronic (32 weeks) exposure to occupationally relevant concentrations of the environmental pollutant trichloroethylene (TCE) induced autoimmune hepatitis (AIH) in autoimmune-prone MRL+/+ mice. In real-life, individuals are never exposed to only one chemical such as TCE. However, very little is known about the effects of chemical mixtures on the immune system. The current study examined whether coexposure to another known immunotoxicant, mercuric chloride (HgCl2), altered TCE-induced AIH. Female MRL+/+ mice were treated for only 8 weeks with TCE (9.9 or 186.9 mg/kg/day in drinking water) and/or HgCl2 (260 μg/kg/day, sc). Unlike mice exposed to either TCE or HgCl2 alone, mice exposed to both toxicants for 8 weeks developed significant liver pathology commensurate with early stages of AIH. Disease development in the coexposed mice was accompanied by a unique pattern of anti-liver and anti-brain antibodies that recognized, among others, a protein of approximately 90 kDa. Subsequent immunoblotting showed that sera from the coexposed mice contained antibodies specific for heat shock proteins, a chaperone protein targeted by antibodies in patients with AIH. Thus, although TCE can promote autoimmune disease following chronic exposure, a shorter exposure to a binary mixture of TCE and HgCl2 accelerated disease development. Coexposure to TCE and HgCl2 also generated a unique liver-specific antibody response not found in mice exposed to a single toxicant. This finding stresses the importance of including mixtures in assessments of chemical immunotoxicity. PMID:21084432

  13. Displacement of soil pore water by trichloroethylene

    USGS Publications Warehouse

    Wershaw, R. L.; Aiken, G.R.; Imbrigiotta, T.E.; Goldberg, M.C.

    1994-01-01

    Dense nonaqueous phase liquids (DNAPLS) are important pollutants because of their widespread use as chemical and industrial solvents. An example of the pollution caused by the discharge of DNAPLs is found at the Picatinny Arsenal, New Jersey, where trichloroethylene (TCE) has been discharged directly into the unsaturated zone. This discharge has resulted in the formation of a plume of TCE-contaminated water in the aquifer downgradient of the discharge. A zone of dark-colored groundwater containing a high dissolved organic C content has been found near the point of discharge of the TCE. The colored-water plume extends from the point of discharge at least 30 m (100 feet) downgradient. Fulvic acids isolated from the colored-waters plume, from water from a background well that has not been affected by the discharge of chlorinated solvents, and from soil pore water collected in a lysimeter installed at an uncontaminated site upgradient of the study area have been compared. Nuclear magnetic resonance spectra of the fulvic acids from the colored waters and from the lysimeter are very similar, but are markedly different from the nuclear magnetic resonance spectrum of the fulvic acid from the background well. The three-dimensional fluorescence spectrum and the DOC fractionation profile of the colored groundwater and the soil pore water are very similar to each other, but quite different from those of the background water. It is proposed from these observations that this colored water is soil pore water that has been displaced by a separate DNAPL liquid phase downward to the saturated zone.

  14. EFFECTS OF ORAL EXPOSURE TO TRICHLOROETHYLENE ON FEMALE REPRODUCTIVE FUNCTION

    EPA Science Inventory

    In the present study, the distribution, metabolism and reproductive toxicity of trichloroethylene (TCE) administered by the oral route to female rats were examined. The distribution study with 14C-TCE indicated that relatively high levels of radioactivity accumulated in the ovary...

  15. EFFECTS OF TRICHLOROETHYLENE EXPOSURE ON MALE REPRODUCTIVE FUNCTION IN RATS

    EPA Science Inventory

    The present study was designed to evaluate the influences of trichloroethylene (TCE) on the reproductive system of male rats. In addition, information was obtained on the distribution and metabolism of TCE. At 100 days of age, male rats were allowed to copulate with ovariectomize...

  16. Chronic dysphagia and trigeminal anesthesia after trichloroethylene exposure

    SciTech Connect

    Lawrence, W.H.; Partyka, E.K.

    1981-12-01

    A patient is described who inhaled trichloroethylene fumes while working in a closed underground pit. At the time of exposure he developed dysphagia, dysarthria and dyspnea. Assessment of his condition 11 years after the incident indicated major damage of cranial nerves, particularly the trigeminal, chronic involvement of the bulbar cranial nerves, and resultant esophageal and pharnygeal motility impairment. (JMT)

  17. IRIS Toxicological Review of Trichloroethylene (Interagency Science Consultation Draft)

    EPA Science Inventory

    On November 3, 2009, the Toxicological Review of Trichloroethylene and the charge to external peer reviewers were released for external peer review and public comment. The Toxicological Review and charge were reviewed internally by EPA and by other federal agencies and White Hous...

  18. USE OF GRANULAR GRAPHITE FOR ELECTROLYTIC DECHLORINATION OF TRICHLOROETHYLENE

    EPA Science Inventory

    Granular graphite is a potential electrode material for the electrochemical remediation of refractory chlorinated organic compounds such as trichloroethylene (TCE). However, the use of granular graphite can complicate the experimental results. On one hand, up to 99% of TCE was re...

  19. THE EFFECT OF VOLTAGE ON ELECTROCHEMICAL DEGRADATION OF TRICHLOROETHYLENE

    EPA Science Inventory

    This study investigates electrochemical degradation of Trichloroethylene (TCE) using granular graphite as electrodes in a flow-through reactor system. The experiments were conducted to obtain information on the effect of voltage and flow rates on the degradation rates of TCE. The...

  20. EFFECTS OF THERMAL TREATMENTS ON THE CHEMICAL REACTIVITY OF TRICHLOROETHYLENE

    EPA Science Inventory

    A series of experiments was completed to investigate abiotic degradation and reaction product formation of trichloroethylene (TCE) when heated. A quartz-tube apparatus was used to study short residence time and high temperature conditions that are thought to occur during thermal ...

  1. Impact of Iron Sulfide Transformation on Trichloroethylene Degradation

    EPA Science Inventory

    Trichloroethylene (TCE) is one of the most common and persistent groundwater contaminants encountered at hazardous waste sites around the world. A growing body of evidence indicates that iron sulfides play an important role in degrading TCE in natural environments and in enginee...

  2. EFFECT OF TRICHLOROETHYLENE ON MALE SEXUAL BEHAVIOR: POSSIBLE OPIOID ROLE

    EPA Science Inventory

    Trichloroethylene (TCE) is a chlorinated hydrocarbon solvent which is widely used as an industrial degreasing agent. Workers exposed to TCE often exhibit symptoms similar to those symptoms produced by narcotics. The present studies evaluated the effects of TCE exposure on measure...

  3. ADSORPTION AND CATALYTIC DESTRUCTION OF TRICHLOROETHYLENE IN HYDROPHOBIC ZEOLITES

    EPA Science Inventory

    Several chromium exchanged ZSM-5 zeolites of varying SiO2/Al2O3 ratio were prepared and investigated for ambient (23 ?C) adsorption and subsequent oxidative destruction (250-400 ?C) of gaseous trichloroethylene (TCE, Cl2C=CHCl) in a humid air stream. With an increase in the SiO2...

  4. BIODEGRADATION OF TRICHLOROETHYLENE AND INVOLVEMENT OF AN AROMATIC BIODEGRADATIVE PATHWAY

    EPA Science Inventory

    Biodegradation of trichloroethylene (TCE) by the bacterial isolate strain G4 resulted in complete dechlorination of the compound as indicated by the production of inorganic chloride. A component of the water from which strain G4 was isolated that was required for TCE degradation ...

  5. Trichloroethylene toxicity in a human hepatoma cell line

    SciTech Connect

    Thevenin, E.; McMillian, J.

    1994-12-31

    The experiments conducted in this study were designed to determine the usefullness of hepatocyte cultures and a human hepatoma cell line as model systems for assessing human susceptibility to hepatocellular carcinoma due to exposure to trichloroethylene. The results from these studies will then be analyzed to determine if human cell lines can be used to conduct future experiments of this nature.

  6. FULL SCALE EVALUATION OF IN SITU COMETABOLIC DEGRADATION OF TRICHLOROETHYLENE IN GROUNDWATER THROUGH TOLUENE INJECTION. (R825689C067)

    EPA Science Inventory

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  7. 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)].

  8. Interfacial Properties of a Hydrophobic Dye in the Tetrachloroethylene-Water-Glass Systems

    SciTech Connect

    Tuck, D.M.

    1999-02-23

    Interfacial effects play an important role in governing multiphase fluid behavior in porous media. Strongly hydrophobic organic dyes, used in many experimental studies to facilitate visual observation of the phase distributions, have generally been implicitly assumed to have no influence on the interfacial properties of the various phases in porous media. Sudan IV is the most commonly used dye for non-aqueous phase liquids (NAPLs) in laboratory experiments. It has also been used in at least one field experiment. The effects of this dye on the tetrachloroethylene (PCE)-water-glass system were investigated to test the assumption that the dye does not effect the interfacial properties and therefore PCE mobility. The results indicate that the dye does indeed change the interfacial relationships.The effect of the dye on the interfacial relationships is a complex function of the dye concentration, the solid phase composition, and the dynamic rate of new interface formation. The dye caused a slight (<10 percent) increase in interfacial tension at low concentrations (<0.1 g/L) and high rates of new interface formation. The dye reduced interfacial tension between PCE and water at low rates of new interface formation for all dye concentrations tested (0.00508 to 5.08 g/L). At the highest dye concentration, the PCE-water interfacial tension was significantly reduced regardless of the rate of new interface formation. The apparent interfacial tension increase at low dye concentrations is suspected to be an artifact of a low measured IFT value for the undyed PCE caused by leaching of rubber o-rings by the PCE prior to testing in the final drop-volume configuration.In addition to reducing interfacial tension, the dye was found to significantly alter the wetting relationship between PCE and water on a glass surface at and above the range of reported dye concentrations cited in the literature (1.1 to 1.7 g/L). The wetting relationship was rendered neutral from a water-wet initial

  9. Apartment residents' and day care workers' exposures to tetrachloroethylene and deficits in visual contrast sensitivity.

    PubMed Central

    Schreiber, Judith S; Hudnell, H Kenneth; Geller, Andrew M; House, Dennis E; Aldous, Kenneth M; Force, Michael S; Langguth, Karyn; Prohonic, Elizabeth J; Parker, Jean C

    2002-01-01

    Tetrachloroethylene (also called perchloroethylene, or perc), a volatile organic compound, has been the predominant solvent used by the dry-cleaning industry for many years. The U.S. Environmental Protection Agency (EPA) classified perc as a hazardous air pollutant because of its potential adverse impact on human health. Several occupational studies have indicated that chronic, airborne perc exposure adversely affects neurobehavioral functions in workers, particularly visual color discrimination and tasks dependent on rapid visual-information processing. A 1995 study by Altmann and colleagues extended these findings, indicating that environmental perc exposure at a mean level of 4,980 microg/m(3) (median=1,360 microg/m(3)) alters neurobehavioral functions in residents living near dry-cleaning facilities. Although the U.S. EPA has not yet set a reference concentration guideline level for environmental exposure to airborne perc, the New York State Department of Health set an air quality guideline of 100 microg/m(3). In the current residential study, we investigated the potential for perc exposure and neurologic effects, using a battery of visual-system function tests, among healthy members of six families living in two apartment buildings in New York City that contained dry-cleaning facilities on the ground floors. In addition, a day care investigation assessed the potential for perc exposure and effects among workers at a day care center located in the same one-story building as a dry-cleaning facility. Results from the residential study showed a mean exposure level of 778 microg/m(3) perc in indoor air for a mean of 5.8 years, and that perc levels in breath, blood, and urine were 1-2 orders of magnitude in excess of background values. Group-mean visual contrast sensitivity (VCS), a measure of the ability to detect visual patterns, was significantly reduced in the 17 exposed study participants relative to unexposed matched-control participants. The groups did not

  10. Cometabolic biodegradation of trichloroethylene in microcosms

    USGS Publications Warehouse

    Kane, Allen C.; Wilson, Timothy P.; Fischer, Jeffrey M.

    1997-01-01

    Laboratory microcosms were used to determine the concentrations of oxygen (O2) and methane (CH4) that optimize trichloroethylene (TCE) biodegradation in sediment and ground-water samples from a TCE-contaminated aquifer at Picatinny Arsenal, Morris County, New Jersey. The mechanism for degradation is the cometabolic activity of methanotrophic bacteria. The laboratory data will be used to support a field study designed to demonstrate the effectiveness of combining air sparging with cometabolic degradation of TCE for the purpose of aquifer remediation. Microcosms were constructed in autoclaved 250-mL (milliliter) amber glass bottles with valves for repeated headspace sampling. Equal volumes (25 mL) of sediment and ground water, collected from a depth of 40 feet, were added. TCE was added to attain initial aqueous concentrations equal to the field level of 1,400 mu g/L (micrograms per liter). Nine microcosms were constructed with initial headspace O2 concentrations of 5%, 10%, or 14% and CH4 concentrations of 0.5%, 3%, or 5%, with nitrogen making up the balance. Sterile controls, controls without CH4, and controls without sediment were also constructed. A 4-mL gas sample was removed periodically and TCE, O2 , CH4 , and carbon dioxide (CO2) concentrations were measured by using gas chromatography. As biodegradation proceeded, the decrease in O2, CH4 , and TCE concentrations and the production of CO2 were monitored. An initial acclimation period of at least 100 days was observed in those microcosms in which significant microbial activity occurred, as determined from decreases in O2 and CH4 concentrations and an increase in CO2 content. Degradation of TCE occurred with O2 concentrations of 2.7 to 8.7% and CH4 concentrations of 0.5 to 3.5%. Microcosms that initially contained 10% O2 and 3% CH4 showed the greatest microbial activity and the greatest amount of TCE degradation. The greatest rates of TCE degradation occurred when O2 and CH4 headspace concentrations reached

  11. Toluene Monooxygenase-Catalyzed Epoxidation of Alkenes

    PubMed Central

    McClay, Kevin; Fox, Brian G.; Steffan, Robert J.

    2000-01-01

    Several toluene monooxygenase-producing organisms were tested for their ability to oxidize linear alkenes and chloroalkenes three to eight carbons long. Each of the wild-type organisms degraded all of the alkenes that were tested. Epoxides were produced during the oxidation of butene, butadiene, and pentene but not hexene or octadiene. A strain of Escherichia coli expressing the cloned toluene-4-monooxygenase (T4MO) of Pseudomonas mendocina KR1 was able to oxidize butene, butadiene, pentene, and hexene but not octadiene, producing epoxides from all of the substrates that were oxidized. A T4MO-deficient variant of P. mendocina KR1 oxidized alkenes that were five to eight carbons long, but no epoxides were detected, suggesting the presence of multiple alkene-degrading enzymes in this organism. The alkene oxidation rates varied widely (ranging from 0.01 to 0.33 μmol of substrate/min/mg of cell protein) and were specific for each organism-substrate pair. The enantiomeric purity of the epoxide products also varied widely, ranging from 54 to >90% of a single epoxide enantiomer. In the absence of more preferred substrates, such as toluene or alkenes, the epoxides underwent further toluene monooxygenase-catalyzed transformations, forming products that were not identified. PMID:10788354

  12. Dynamics of toluene degradation in biofilters

    SciTech Connect

    Tang, Hsiu-Mu; Hwang, Shyh-Jye; Hwang, Sz-Chwun

    1995-12-31

    Biodegradation processes have been validated as a promising alternative to other conventional air pollution control technologies. The objective of this research was to systematically investigate the transient behavior of shut down and restart-up operation and shock loading of the biofilter. Experiments were conducted in three laboratory-scale biofilters with mixtures of chaff/compost, D.E. (diatomaceous earth)/compost, and GAC (granular activated carbon)/compost, respectively as the filter materials. Toluene was used as the gas pollutant in this study. The response of each biofilter to shock loading was studied by abruptly changing the concentration or flow rate of the inlet gas. For each transient operation, toluene concentration was continuously measured until a new steady state was achieved. The results indicated that the biofilters responded effectively to the shut down and restart-up operation and shock loading of toluene concentration or gas flow rate. Moreover, the highly adsorptive GAC could improve the biofilter performance, especially for the treatment of less water soluble compounds such as toluene. Therefore, the GAC/compost biofilter had the highest maximum elimination capacity of 97 (g hr{sup {minus}1} m{sup {minus}3}). 17 refs., 8 figs.

  13. HEALTH ASSESSMENT DOCUMENT FOR TOLUENE. FINAL REPORT

    EPA Science Inventory

    The health effect of primary concern with regard to exposures of humans to toluene is dysfunction of the central nervous system (CNS). Occupational exposures in the range of 200 to 1,500 ppm have elicited dose-related CNS alterations. Although myelotoxicity was previously attribu...

  14. Gas chromatographic determination of residual methylene chloride and trichloroethylene in decaffeinated instant and ground coffee with electrolytic conductivity and electron capture detection.

    PubMed

    Page, B D; Charbonneau, C F

    1977-05-01

    A method is described for the quantitative determination of residual methylene chloride (MC) and trichloroethylene (TCE) in decaffeinated instant and ground roasted coffees. The residual solvents were isolated by a closed system vacuum distillation technique with toluene as a carrier solvent, chromatographed on Chromosorb 102, detected by both electron capture and electrolytic conductivity detectors, and quantitated by comparison with an internal standard. Average recoveries of MC from instant and ground coffees spiked at 1, 10, and 25 ppm were 100.0 (88-113), 93.2 (92-95), and 97.7% (94-102%); and for TCE, 97.2 (92-101), 96.2 (95-99), and 96.5% (92-100%), respectively. The results from both detectors are compared. At lower attenuations, levels less than 1 ppm can be readily measured. The procedure developed was applied to domestic and imported coffee samples. PMID:858707

  15. Project Overview: IRIS TOXICOLOGICAL REVIEW AND SUMMARY DOCUMENTS FOR TOLUENE

    EPA Science Inventory

    Toluene is used as an additive to gasoline mixtures (BTEX) to increase octane ratings, in benzene production, and as a solvent in paints, coatings, inks, adhesives, and cleaners. Additionally, toluene is used in the production of nylon, plastics, and polyurethanes. Toluene was o...

  16. CONCENTRATION OF TETRACHLOROETHYLENE IN INDOOR AIR AT A FORMER DRY CLEANER FACILITY AS A FUNCTION OF SUBSURFACE CONTAMINATION: A CASE STUDY

    EPA Science Inventory

    A field study was performed to evaluate indoor air concentrations and vapor intrusion (VI) of tetrachloroethylene (PCE) and other chlorinated solvents at a commercial retail site in Dallas, TX. The building is approximately 40 years old and once housed a dry cleaning operation. R...

  17. Metabolism and Excretion of Trichloroethylene after Inhalation by Human Subjects

    PubMed Central

    Bartoníček, V.

    1962-01-01

    Eight volunteers were exposed to trichloroethylene vapour (1,042 μg./l.) for five hours; 51 to 64% of the inhaled trichloroethylene was retained. The concentration of trichloroethanol and trichloroacetic acid in the urine was studied daily for a three-week period; on the third day both metabolites were determined in faeces, sweat, and saliva. The concentration of trichloroacetic acid in plasma and red blood cells was studied on alternate days. Of the trichloroethylene retained, 38·0 to 49·7% was excreted in the urine as trichloroethanol and 27·4 to 35·7% as trichloroacetic acid. Of both metabolites 8·4% was excreted in the faeces. Sweat collected on the third day of the experiment contained 0·10 to 1·92 mg./100 ml. trichloroethanol and 0·15 to 0·35 mg./100 ml. trichloroacetic acid. In saliva the concentrations were 0·09 to 0·32 mg./100 ml. trichloroethanol and 0·10 to 0·15 mg./100 ml. trichloroacetic acid. The value of the expression trichloroethanol/trichloroacetic acid calculated in the urine within 22 days was within the range 1·15 to 1·81. PMID:13865497

  18. Decomposition characteristics of toluene by a corona radical shower system.

    PubMed

    Wu, Zu-liang; Gao, Xiang; Luo, Zhong-yang; Ni, Ming-jiang; Cen, Ke-fa

    2004-01-01

    Non-thermal plasma technologies offer an innovative approach to decomposing various volatile organic compounds(VOCs). The decomposition of toluene from simulated flue gas was investigated using a pipe electrode with nozzles for the generation of free radicals. Corona characteristics and decomposition of toluene were investigated experimentally. In addition, the decomposition mechanism of toluene was explored in view of reaction rate. The experimental results showed that the humidity of additional gas has an important effect on corona characteristics and modes and stable streamer corona can be generated through optimizing flow rate and humidity of additional gas. Applied voltage, concentration of toluene, humidity of toluene and resident time are some important factors affecting decomposition efficiency. Under optimizing conditions, the decomposition efficiency of toluene can reach 80%. These results can give a conclusion that the corona radical shower technology is feasible and effective on the removal of toluene in the flue gas. PMID:15495952

  19. Health assessment for Nutmeg Valley, Wolcott, Connecticut, Region 1. CERCLIS No. CTSI88045. Preliminary report

    SciTech Connect

    Not Available

    1988-05-02

    The Nutmeg Valley Industrial Park is listed on the National Priorities List. The site is an industrial park containing 40 companies (light industry metal working and finishing) and 20 private residences. The contaminants present in groundwater at the site are trichloroethylene, benzene, ethyl benzene, toluene, xylene, methylene chloride, trans 1,2-dichloroethane, 1,1,1-trichloroethane, tetrachloroethylene, pentane, carbon tetrachloride, and chloroform. Investigation into the extent of contamination in other pathways is ongoing.

  20. Health effects of the alkylbenzenes. I. Toluene.

    PubMed

    Low, L K; Meeks, J R; Mackerer, C R

    1988-03-01

    The alkylbenzenes, toluene being the most common example, represent a class of six-membered ring aromatic compounds that have a variety of alkyl groups attached. These chemicals are liquids with relatively low boiling points and are used primarily as solvents or as starting materials in the synthesis of other chemicals and drugs. They are also integral components of gasoline, distillate fuels and other petroleum products. These substituted aromatics are economically important in the chemical, petroleum, pharmaceutical, polymer, paint and dye industries. Alkylbenzenes such as toluene, xylene, ethylbenzene, styrene and cumene are toxicologically important since they are produced, used or disposed of in the largest quantities and therefore might pose significant and potential health risks to man and the environment. In general, the toxicity of alkylbenzenes has been found to be relatively low. Also, for the most part, human and environmental risks are low; however, there may be a few operations where the potential for high exposure could exist. These exposures are minimized by workplace controls or personal protective equipment. Furthermore, health risks for humans are minimized by guidelines for maximum allowable exposure concentrations which have been established for the workplace. This present paper reviews the toxicology and disposition of toluene in animals and humans. PMID:3291202

  1. Catalytic conversion of pyrolysis gasoline and toluene

    SciTech Connect

    Syunyakova, Z.F.; Valitov, R.B.; Shmelev, A.S.; Mazitov, M.F.; Faskhutdinova, R.A.; Sokolova, G.P.

    1984-11-01

    A basic process for production of benzene from petroleum, along with catalytic reforming, is processing of liquid pyrolysis products and toluene. The conversion of pyrolysis gasoline and toluene on an iron-chromium oxide catalyst in a medium of steam and hydrogen at atmospheric pressure was investigated. Catalytic conversion of the pyrolysis gasoline was carried out in a medium of steam in a gradientless spherical reactor made of Kh23N18T steel under the following conditions: temperature 750 to 840/sup 0/C; steam pyrolysis gasoline weight ratio 1:1; pyrolysis gasoline feed rate 1 g per g catalyst per hour; experiment time 1 hour; catalyst volume 8 cm/sup 3/. Hydrodealkylation of toluene was also studied with the goal of producing benzene. In contrast to the conversion of pyrolysis gasoline in a medium of steam, hydrodealkylation was accomplished in a medium of steam and hydrogen. The preliminary tests showed that higher selectivity for formation of benzene is achieved in the presence of hydrogen. 11 references, 4 tables.

  2. USE OF CARBON STABLE ISOTOPE TO INVESTIGATE CHLOROMETHANE FORMATION IN THE ELECTROLYTIC DECHLORINATION OF TRICHLOROETHYLENE

    EPA Science Inventory

    Carbon stable isotope trichloroethylene (13C TCE) was used to investigate the formation of chloromethane (CM) during the electrolytic dechlorination of trichloroethylene (TCE) at a granular-graphite packed cathode. A method was developed to use a conventional GC/MS to ...

  3. Benzodiazepine-like discriminative stimulus effects of toluene vapor

    PubMed Central

    Shelton, Keith L.; Nicholson, Katherine L.

    2013-01-01

    In vitro studies show that the abused inhalant toluene affects a number of ligand-gated ion channels. The two most consistently implicated of these are γ-aminobutyric acid type A (GABAA) receptors which are positively modulated by toluene and N-methyl-D-aspartate (NMDA) receptors which are negatively modulated by toluene. Behavioral studies also suggest an interaction of toluene with GABAA and/or NMDA receptors but it is unclear if these receptors underlie the abuse-related intoxicating effects of toluene. Seventeen B6SJLF1/J mice were trained using a two-choice operant drug discrimination procedure to discriminate 10 min of exposure to 2000 ppm toluene vapor from 10 min of exposure to air. The discrimination was acquired in a mean of 65 training sessions. The stimulus effects of 2000 ppm toluene vapor were exposure concentration-dependent but rapidly diminished following the cessation of vapor exposure. The stimulus effects of toluene generalized to the chlorinated hydrocarbon vapor perchloroethylene but not 1,1,2-trichloroethane nor the volatile anesthetic isoflurane. The competitive NMDA antagonist CGS-17955, the uncompetitive antagonist dizocilpine and the glycine-site antagonist L701,324 all failed to substitute for toluene. The classical nonselective benzodiazepines midazolam and chlordiazepoxide produced toluene-like stimulus effects but the alpha 1 subunit preferring positive GABAA modulator zaleplon failed to substitute for toluene. The barbiturates pentobarbital and methohexital and the GABAA-positive modulator neurosteroid allopregnanolone did not substitute for toluene. These data suggest that the stimulus effects of toluene may be at least partially mediated by benzodiazepine-like positive allosteric modulation of GABAA receptors containing alpha 2, 3 or 5 subunits. PMID:24436974

  4. [Advances in non-carcinogenic toxicity of trichloroethylene].

    PubMed

    Huang, Peiwu; Li, Xuan; Liu, Wei; Liu, Jianjun

    2015-09-01

    Trichloroethylene (TCE) is a widely used organic solvent and an important industrial material. Due to mass production and use, and improper waste disposal, TCE has become a common environmental contaminant, so there is a wide range of occupationally and environmentally exposed population. Occupational and environmental exposure to TCE can produce toxic effects on multiple organs and systems. This paper is a review of the immunotoxicity, reproductive toxicity, neurotoxicity, teratogenic effect and other non-carcinogenic toxic effects of TCE from the aspects of epidemiological study, experimental evidence on animals and toxic mechanisms. PMID:26733146

  5. Electronic and Photoelectron Spectroscopy of Toluene

    NASA Astrophysics Data System (ADS)

    Gardner, Adrian M.; Green, Alistair M.; Tame-Reyes, Victor; Wright, Timothy G.

    2012-06-01

    Electronic and photoelectron spectra of toluene are presented and discussed. The utilization of a recently reported scheme for assigning the normal vibrations of substituted benzenes allows these spectra to be compared to those of other molecules with unprecedented clarity. Changes in vibrational activity within a series of substituted benzene molecules will be discussed, specifically the increased rate of intramolecular vibrational energy redistribution observed in molecules where the substituent is a methyl group. A. M. Gardner and T. G. Wright, J. Chem. Phys., 135, 114305 (2011)

  6. Permeation of polymeric materials by toluene

    SciTech Connect

    Vahdat, N.

    1987-02-01

    The permeation of toluene through protective clothing materials composed of butyl, butyl-coated nomex, neoprene, and polyvinyl alcohol was tested at 25/sup 0/C and 45/sup 0/C with the use of ASTM method F-739. Butyl exhibited breakthrough of 18 min at 25/sup 0/C and 11 min at 45/sup 0/ C. Butyl nomex exhibited breakthrough times of 11 min and 25/sup 0/C and 6 min at 45/sup 0/C. PVA showed no breakthrough in 20 hr. The steady-state permeation rates and the diffusion coefficients were determined.

  7. Anaerobic degradation of toluene by a denitrifying bacterium.

    PubMed Central

    Evans, P J; Mang, D T; Kim, K S; Young, L Y

    1991-01-01

    A denitrifying bacterium, designated strain T1, that grew with toluene as the sole source of carbon under anaerobic conditions was isolated. The type of agar used in solid media and the toxicity of toluene were determinative factors in the successful isolation of strain T1. Greater than 50% of the toluene carbon was oxidized to CO2, and 29% was assimilated into biomass. The oxidation of toluene to CO2 was stoichiometrically coupled to nitrate reduction and denitrification. Strain T1 was tolerant of and grew on 3 mM toluene after a lag phase. The rate of toluene degradation was 1.8 mumol min-1 liter-1 (56 nmol min-1 mg of protein-1) in a cell suspension. Strain T1 was distinct from other bacteria that oxidize toluene anaerobically, but it may utilize a similar biochemical pathway of oxidation. In addition, o-xylene was transformed to a metabolite in the presence of toluene but did not serve as the sole source of carbon for growth of strain T1. This transformation was dependent on the degradation of toluene. Images PMID:2059037

  8. Remediation of an aquifer polluted with dissolved tetrachloroethylene by an array of wells filled with activated carbon.

    PubMed

    Bortone, I; Di Nardo, A; Di Natale, M; Erto, A; Musmarra, D; Santonastaso, G F

    2013-09-15

    In this work, an array of deep passive wells filled with activated carbon, namely a Discontinuous Permeable Adsorptive Barrier (PAB-D), has been proposed for the remediation of an aquifer contaminated by tetrachloroethylene (PCE). The dynamics of the aquifer in the particular PAB-D configuration chosen, including the contaminant transport in the aquifer and the adsorption onto the barrier material, has been accurately performed by means of a computer code which allows describing all the phenomena occurring in the aquifer, simultaneously. A PAB-D design procedure is presented and the main dimensions of the barrier (number and position of passive wells) have been evaluated. Numerical simulations have been carried out over a long time span to follow the contaminant plume and to assess the effectiveness of the remediation method proposed. The model results show that this PAB-D design allows for a complete remediation of the aquifer under a natural hydraulic gradient, the PCE concentrations flowing out of the barrier being always lower than the corresponding Italian regulation limit. Finally, the results have been compared with those obtained for the design of a more traditional continuous barrier (PAB-C) for the same remediation process. PMID:23876256

  9. Tetrachloroethylene in drinking water and birth outcomes at the US Marine Corps Base at Camp Lejeune, North Carolina.

    PubMed

    Sonnenfeld, N; Hertz-Picciotto, I; Kaye, W E

    2001-11-15

    A study of mean birth weight, small-for-gestational-age infants, and preterm birth was conducted at the US Marine Corps Base at Camp Lejeune, North Carolina, where drinking water was contaminated with volatile organic compounds. Tetrachloroethylene (PCE) was the predominant contaminant. The authors used multiple linear and logistic regression to analyze 1968-1985 data from 11,798 birth certificates. Overall, at most weak associations were observed between PCE exposure and study outcomes. However, associations were found between PCE exposure and birth-weight outcomes for infants of older mothers and mothers with histories of fetal loss. Adjusted mean birth-weight differences between PCE-exposed and unexposed infants were -130 g (90% confidence interval (CI): -236, -23) for mothers aged 35 years or older and -104 g (90% CI: -174, -34) for mothers with two or more previous fetal losses. Adjusted odds ratios for PCE exposure and small-for-gestational-age infants were 2.1 (90% CI: 0.9, 4.9) for older mothers and 2.5 (90% CI: 1.5, 4.3) for mothers with two or more prior fetal losses. These results suggest that some fetuses may be more vulnerable than others to chemical insult. PMID:11700244

  10. BEHAVIOR OF TOLUENE ADDED TO SLUDGE-AMENDED SOILS

    EPA Science Inventory

    Toluene is a priority pollutant that can be introduced to soils in a variety of wastes, including some municipal sludges. Laboratory experiments were conducted to study the behavior of toluene in two soils in the presence and absence of municipal sludge. Sludge additions increa...

  11. CARDIOVASCULAR AND THERMOREGULATORY RESPONSE TO ORAL TOLUENE IN THE RAT.

    EPA Science Inventory

    Toluene and other volatile organic compounds have often been shown to affect behavior in animals when given by inhalation, and less effective when given orally. Previous work showed that toluene increased heart rate (HR) and motor activity (MA), and reduced core temperature (Tc) ...

  12. BEHAVIOR OF TOLUENE ADDED TO SLUDGE-AMENDED SOILS

    EPA Science Inventory

    Toluene is a priority pollutant that can be introduced to soils in a variety of wastes, including some municipal sludges. aboratory experiments were conducted to study the behavior of toluene in two soils in the presence and absence of municipal sludge. ludge additions increased ...

  13. TOLUENE EXPERIMENTAL EXPOSURES IN HUMANS: PHARMACOKINETICS AND BEHAVIOR

    EPA Science Inventory

    Toluene Experimental Exposures in Humans:
    Pharmacokinetics and Behavioral Effects
    (Ongoing Research)

    Vernon A. Benignus1, Philip J. Bushnell2 and William K. Boyes2

    Human subjects will be exposed to 250 and 500 ppm toluene for one hour in the Human St...

  14. PERFORMANCE OF TRICKLE BED BIOFILTERS UNDER HIGH TOLUENE LOADING

    EPA Science Inventory

    The performance of two pelletized media biofilters, highly loaded with toluene, was evaluated in this study. oth biofilters were operated as the same influent concentration of 250 ppmv toluene. iofilter "A" was operated at 1 minute EBRT and biofilter "B" at 0.67 minute EBRT. he i...

  15. Toluene inducing acute respiratory failure in a spray paint sniffer

    PubMed Central

    Peralta, Diego P.; Chang, Aymara Y.

    2012-01-01

    Summary Background: Toluene, formerly known as toluol, is an aromatic hydrocarbon that is widely used as an industrial feedstock and as a solvent. Like other solvents, toluene is sometimes also used as an inhalant drug for its intoxicating properties. It has potential to cause multiple effects in the body including death. Case Report: I report a case of a 27-year-old male, chronic spray paint sniffer, who presented with severe generalized muscle weakness and developed acute respiratory failure requiring ventilatory support. Toluene toxicity was confirmed with measurement of hippuric acid of 8.0 g/L (normal <5.0 g/L). Conclusions: Acute respiratory failure is a rare complication of chronic toluene exposure that may be lethal if it is not recognized immediately. To our knowledge, this is the second case of acute respiratory failure due to toluene exposure. PMID:23569498

  16. Optical emission study of radio-frequency excited toluene plasma.

    PubMed

    Lee, Szetsen; Liu, Shiao-Jun; Liang, Rui-Ji

    2008-12-25

    UV-visible emission spectra of radio-frequency (rf) excited toluene plasma were studied. Benzyl radicals as well as toluene monomer and excimer were observed in toluene plasma. It was found that the intensities, peak positions, and linewidths of monomer and excimer emission bands exhibit strong dependence on rf power and plasma processing time. This can be ascribed to photochemical reactions in plasma. Gas-chromatographic analysis of the deposition products from toluene plasma indicated that the main component was bibenzyl. Spectroscopic evidence has shown that the bibenzyl molecule was formed by the coupling reaction between two benzyl radicals in plasma. The spectroscopic characteristics of toluene monomer and excimer are correlated with a kinetic model in plasma. PMID:19049320

  17. Synergistic effect of nano-sized mackinawite with cyano-cobalamin in cement slurries for reductive dechlorination of tetrachloroethylene.

    PubMed

    Kyung, Daeseung; Sihn, Youngho; Kim, Sangwoo; Bae, Sungjun; Amin, Muhammad Tahir; Alazba, Abdulrahman Ali; Lee, Woojin

    2016-07-01

    Experiments were conducted to investigate the reductive dechlorination of tetrachloroethylene (PCE) by nano-Mackinawite (nFeS) with cyano-cobalamin (Cbl(III)) in cement slurries. Almost complete degradation of PCE by nFeS-Cbl(III) was observed in cement slurries in 5h and its degradation kinetics (kobs-PCE=0.57h(-1)) was 6-times faster than that of nFeS-Cbl(III) without the cement slurries. PCE was finally transformed to non-chlorinated organic compounds such as ethylene, acetylene, and C3-C4 hydrocarbons by nFeS-Cbl(III) in cement slurries. X-ray photoelectron spectroscopy and PCE degradation by cement components (SiO2, Al2O3, and CaO) revealed that both the reduced Co species in Cbl(III) and the presence of Ca in cement played an important role for the enhanced reductive dechlorination of PCE. The increase in the concentration of Cbl(III) (0.005-0.1mM), cement ratio (0.05-0.2), and suspension pH (11.5-13.5) accelerated the PCE degradation kinetics by providing more favorable environments for the production of reactive Ca species and reduction of Co species. We also observed that the degradation efficiency of PCE by nFeS-Cbl(III)-cement lasted even at high concentration of PCE. The experimental results obtained from this study could provide fundamental knowledge of redox interactions among nFeS, Cbl(III), and cement, which could significantly enhance reductive dechlorination of chlorinated organics in contaminated natural and engineered environments. PMID:26950611

  18. Prenatal exposure to tetrachloroethylene-contaminated drinking water and the risk of congenital anomalies: a retrospective cohort study

    PubMed Central

    2009-01-01

    Background Prior animal and human studies of prenatal exposure to solvents including tetrachloroethylene (PCE) have shown increases in the risk of certain congenital anomalies among exposed offspring. Objectives This retrospective cohort study examined whether PCE contamination of public drinking water supplies in Massachusetts influenced the occurrence of congenital anomalies among children whose mothers were exposed around the time of conception. Methods The study included 1,658 children whose mothers were exposed to PCE-contaminated drinking water and a comparable group of 2,999 children of unexposed mothers. Mothers completed a self-administered questionnaire to gather information on all of their prior births, including the presence of anomalies, residential histories and confounding variables. PCE exposure was estimated using EPANET water distribution system modeling software that incorporated a fate and transport model. Results Children whose mothers had high exposure levels around the time of conception had an increased risk of congenital anomalies. The adjusted odds ratio of all anomalies combined among children with prenatal exposure in the uppermost quartile was 1.5 (95% CI: 0.9, 2.5). No meaningful increases in the risk were seen for lower exposure levels. Increases were also observed in the risk of neural tube defects (OR: 3.5, 95% CI: 0.8, 14.0) and oral clefts (OR 3.2, 95% CI: 0.7, 15.0) among offspring with any prenatal exposure. Conclusion The results of this study suggest that the risk of certain congenital anomalies is increased among the offspring of women who were exposed to PCE-contaminated drinking water around the time of conception. Because these results are limited by the small number of children with congenital anomalies that were based on maternal reports, a follow-up investigation should be conducted with a larger number of affected children who are identified by independent records. PMID:19778411

  19. Tetrachloroethylene-contaminated drinking water in Massachusetts and the risk of colon-rectum, lung, and other cancers.

    PubMed Central

    Paulu, C; Aschengrau, A; Ozonoff, D

    1999-01-01

    We conducted a population-based case-control study to evaluate the relationship between cancer of the colon-rectum (n = 326), lung (n = 252), brain (n = 37), and pancreas (n = 37), and exposure to tetrachloroethylene (PCE) from public drinking water. Subjects were exposed to PCE when it leached from the vinyl lining of drinking-water distribution pipes. Relative delivered dose of PCE was estimated using a model that took into account residential location, years of residence, water flow, and pipe characteristics. Adjusted odds ratios (ORs) for lung cancer were moderately elevated among subjects whose exposure level was above the 90th percentile whether or not a latent period was assumed [ORs and 95% confidence intervals (CIs), 3.7 (1.0-11.7), 3.3 (0.6-13.4), 6.2 (1.1-31.6), and 19.3 (2.5-141.7) for 0, 5, 7, and 9 years of latency, respectively]. The adjusted ORs for colon-rectum cancer were modestly elevated among ever-exposed subjects as more years of latency were assumed [OR and CI, 1.7 (0.8-3.8) and 2.0 (0.6-5.8) for 11 and 13 years of latency, respectively]. These elevated ORs stemmed mainly from associations with rectal cancer. Adjusted ORs for rectal cancer among ever-exposed subjects were more elevated [OR and CI, 2.6 (0. 8-6.7) and 3.1 (0.7-10.9) for 11 and 13 years of latency, respectively] than were corresponding estimates for colon cancer [OR and CI, 1.3 (0.5-3.5) and 1.5 (0.3-5.8) for 11 and 13 years of latency, respectively]. These results provide evidence for an association between PCE-contaminated public drinking water and cancer of the lung and, possibly, cancer of the colon-rectum. PMID:10090704

  20. Saturation mutagenesis of Bradyrhizobium sp. BTAi1 toluene 4-monooxygenase at alpha-subunit residues proline 101, proline 103, and histidine 214 for regiospecific oxidation of aromatics.

    PubMed

    Yanık-Yıldırım, K Cansu; Vardar-Schara, Gönül

    2014-11-01

    A novel toluene monooxygenase (TMO) six-gene cluster from Bradyrhizobium sp. BTAi1 having an overall 35, 36, and 38 % protein similarity with toluene o-xylene monooxygenase (ToMO) of Pseudomonas sp. OX1, toluene 4-monooxygenase (T4MO) of Pseudomonas mendocina KR1, and toluene-para-monooxygenase (TpMO) of Ralstonia pickettii PKO1, respectively, was cloned and expressed in Escherichia coli TG1, and its potential activity was investigated for aromatic hydroxylation and trichloroethylene (TCE) degradation. The natural substrate toluene was hydroxylated to p-cresol, indicating that the new toluene monooxygenase (T4MO·BTAi1) acts as a para hydroxylating enzyme, similar to T4MO and TpMO. Some shifts in regiospecific hydroxylations were observed compared to the other wild-type TMOs. For example, wild-type T4MO·BTAi1 formed catechol (88 %) and hydroquinone (12 %) from phenol, whereas all the other wild-type TMOs were reported to form only catechol. Furthermore, it was discovered that TG1 cells expressing wild-type T4MO·BTAi1 mineralized TCE at a rate of 0.67 ± 0.10 nmol Cl(-)/h/mg protein. Saturation and site directed mutagenesis were used to generate eight variants of T4MO·BTAi1 at alpha-subunit positions P101, P103, and H214: P101T/P103A, P101S, P101N/P103T, P101V, P103T, P101V/P103T, H214G, and H214G/D278N; by testing the substrates phenol, nitrobenzene, and naphthalene, positions P101 and P103 were found to influence the regiospecific oxidation of aromatics. For example, compared to wild type, variant P103T produced four fold more m-nitrophenol from nitrobenzene as well as produced mainly resorcinol (60 %) from phenol whereas wild-type T4MO·BTAi1 did not. Similarly, variants P101T/P103A and P101S synthesized more 2-naphthol and 2.3-fold and 1.6-fold less 1-naphthol from naphthalene, respectively. PMID:25016343

  1. PHYSIOLOGICALLY BASED PHARMACOKINEITC (PBPK) MODELING OF METABOLIC INHIBITION FOR INTERACTION BETWEEN TRICHLOROETHYLENE AND CHLOROFORM

    EPA Science Inventory

    Trichloroethylene (TCE) and chloroform (CHCl3) are two of the most common environmental contaminants found in water. PBPK models have been increasingly used to predict target dose in internal tissues from available environmental exposure concentrations. A closed inhalation (or g...

  2. Development of a replacement for trichloroethylene in the two-stage cleaning process

    NASA Astrophysics Data System (ADS)

    Harding, W. B.

    1992-12-01

    Isopropyl alcohol, d-limonene, and a synthetic mineral spirits were compared for effectiveness as replacements for trichloroethylene in an ultrasonic cleaning process. All were found to be suitable. Isopropyl alcohol is recommended as the replacement.

  3. Fate and transport of trichloroethane and trichloroethylene contaminated groundwater, building 719, Dover Air Force Base, Delaware

    SciTech Connect

    Melchiorre, K.J.

    1996-08-01

    Trichloroethane and trichloroethylene are common chlorinated aliphatic industrial organic solvents used in degreasing operations. Both are typically found in groundwater environments as a result of leaking underground storage tanks, leachate from landfills, and contaminant migration from hazardous waste dump sites. Transformation by-products are also found in association with trichloroethane and trichloroethylene without any known source other than from reductive dechlorination. Dechlorinated by-products include 1,1-dichloroethane; cis and trans 1,2-dichloroethylene, 1,1-dichloroethylene, chloroethane, and vinyl chloride. Trichloroethane and trichloroethylene and their transformation by-products are suspected human health hazards. Vinyl chloride is a known human carcinogen, while trichloroethylene is considered a probable human carcinogen, and 1,1-dichloroethylene and 1,1-dichloroethane possible human carcinogens.

  4. MODELING THE ELECTROLYTIC DECHLORINATION OF TRICHLOROETHYLENE IN A GRANULAR GRAPHITE-PACKED REACTOR

    EPA Science Inventory

    A comprehensive reactor model was developed for the electrolytic dechlorination of trichloroethylene (TCE) at a granular-graphite cathode. The reactor model describes the dynamic processes of TCE dechlorination and adsorption, and the formation and dechlorination of all the major...

  5. COVALENT BINDING OF TRICHLOROETHYLENE TO PROTEINS IN HUMAN AND RAT HEPATOCYTES. (R826409)

    EPA Science Inventory

    The environmental contaminant and occupational solvent trichloroethylene is metabolized to a reactive intermediate that covalently binds to specific hepatic proteins in exposed mice and rats. In order to compare covalent binding between humans and rodents, primary hepatocyte c...

  6. EFFECTS OF REACTION PARAMETERS ON ELECTROCHEMICAL DECHLORINATION OF TRICHLOROETHYLENE RATE AND BY-PRODUCTS

    EPA Science Inventory

    Trichloroethylene (TCE) was electrochemically dechlorinated in aqueous environments using granular graphite cathode in a mixed reactor. Effects of pH, current, electrolyte type, and flow rate on TCE dechlorination rate were evaluated. TCE dechlorination rate constant and gas prod...

  7. EFFECTS OF REACTOR CONDITIONS ON ELECTROCHEMICAL DECHLORINATION OF TRICHLOROETHYLENE USING GRANULAR-GRAPHITE ELECTRODE.

    EPA Science Inventory

    Trichloroethylene (TCE) was electrochemically dechlorinated in aqueous environments using granular graphite cathode in a mixed reactor. Effects of pH, current, electrolyte type, and flow rate on TCE dechlorination rate were evaluated. TCE dechlorination rate constant and gas pr...

  8. ELECTROCHEMICAL DECHLORINATION OF TRICHLOROETHYLENE USING GRANULAR-GRAPHITE ELECTRODES: IDENTIFICATION AND QUANTIFICATION OF DECHLORINATION PRODUCTS

    EPA Science Inventory

    Electrochemical degradation (ECD) utilizes high redox potential at the anode and low redox potential at the cathode to oxidize and/or reduce organic and inorganic contaminants. ECD of Trichloroethylene (TCE), although theoretically possible, has not been experimentally proven. Th...

  9. EFFECTS OF REACTOR CONDITIONS ON ELECTROCHEMICAL DECHLORINATION OF TRICHLOROETHYLENE USING GRANULAR-GRAPHITE ELECTRODE

    EPA Science Inventory

    Trichloroethylene (TCE) was electrochemically dechlorinated in aqueous environments using granular graphite cathode in a mixed reactor. Effects of pH, current, electrolyte type, and flow rate on TCE dechlorination rate were evaluated. TCE dechlorination rate constant and gas pr...

  10. PHASE-TRANSFER-CATALYST APPLIED TO THE OXIDATION OF TRICHLOROETHYLENE BY POTASSIUM PERMANGANATE

    EPA Science Inventory

    Chlorinated ethylenes such as trichloroethylene (TCE) and perchloroethylene (PCE) are common contaminants (Plumb 1991; Westrick et al., 1984). They opccur in the subsurface as zones of residual saturation or occasionally as free products. Because of their inherently low solubil...

  11. Air trichloroethylene oxidation in a corona plasma-catalytic reactor

    NASA Astrophysics Data System (ADS)

    Masoomi-Godarzi, S.; Ranji-Burachaloo, H.; Khodadadi, A. A.; Vesali-Naseh, M.; Mortazavi, Y.

    2014-08-01

    The oxidative decomposition of trichloroethylene (TCE; 300 ppm) by non-thermal corona plasma was investigated in dry air at atmospheric pressure and room temperature, both in the absence and presence of catalysts including MnOx, CoOx. The catalysts were synthesized by a co-precipitation method. The morphology and structure of the catalysts were characterized by BET surface area measurement and Fourier Transform Infrared (FTIR) methods. Decomposition of TCE and distribution of products were evaluated by a gas chromatograph (GC) and an FTIR. In the absence of the catalyst, TCE removal is increased with increases in the applied voltage and current intensity. Higher TCE removal and CO2 selectivity is observed in presence of the corona and catalysts, as compared to those with the plasma alone. The results show that MnOx and CoOx catalysts can dissociate the in-plasma produced ozone to oxygen radicals, which enhances the TCE decomposition.

  12. Blink reflex latency after exposure to trichloroethylene in well water

    SciTech Connect

    Feldman, R.G.; Chirico-Post, J.; Proctor, S.P.

    1988-03-01

    The electrophysiological measurement of the blink reflex (BR) can quantify the conduction latency in the reflex arc involving the Vth (trigeminal) and VIIth (facial) cranial nerves. We measured the electrophysiological BR in a population (N = 21), which had alleged chronic exposure to trichloroethylene (TCE) through the public drinking water at levels 30-80 times higher than the Environmental Protection Agency (EPA) Maximum Contamination Level (MCL). A highly significant difference was observed in the conduction latency means of the BR components (p less than .0001), when the study population was compared with laboratory controls (N = 27). This difference suggests a subclinical alteration of the Vth cranial nerve function due to chronic, environmental exposure to TCE.

  13. The role of testosterone in trichloroethylene penetration in vitro

    SciTech Connect

    McCormick, K.; Abdel-Rahman, M.S. )

    1991-02-01

    Sex differences are known to exist in the metabolism and bioavailability of trichloroethylene (TCE). This study revealed that dermal penetration of ({sup 14}C)TCE in vitro was twofold greater in untreated female than in untreated male Sprague-Dawley rats. Since testosterone has been shown to mediate a wide variety of sex differences, its role in dermal penetration of ({sup 14}C)TCE was investigated. Penetration was measured by using an in vitro evaporation-penetration cell with a 10-hour collection period. Depriving male rats of testosterone (by castration) resulted in increased values for total penetration, area under the curve (AUC), and penetration slopes compared to those found in the female control group. Administration of testosterone to female animals produced values for total penetration, AUC, and penetration slopes significantly lower than those of the female control group.

  14. [Reductive Dechlorination of Trichloroethylene by Benzoate-Enriched Anaerobic Cultures].

    PubMed

    Li, Jiang-wei; Yang, Xiao-yong; Hu, An-yi; Yu, Chang-ping

    2015-10-01

    Gas chromatography was used to monitor the reductive dechlorination of trichloroethylene (TCE) by anaerobic enrichment cultures with benzoate as the sole carbon source. The 454 pyrosequencing technique was used to investigate the microbial community and the real-time quantitative PCR was used to quantify the gene copies of Dehalococcoides spp. (DHC). The results showed that TCE was dechlorinated to vinyl chloride along with the formation of methane in 94 days. The anaerobic enrichment cultures exhibited a high diversity, which were classified into 16 phyla, 33 classes, 52 orders, 88 families and 129 genera, while 51.2% of them belonged to unclassified group, which inferred that there were a large portion of bacteria with unknown functional in this system. Degradation of TCE was accomplished by reductive dechlorinating and other functional populations, and the DHC which carried tceA gene could be the dominant reductive dechlorinating populations in the system. PMID:26841609

  15. Renal toxicity after chronic inhalation exposure of rats to trichloroethylene.

    PubMed

    Mensing, Thomas; Welge, Peter; Voss, Bruno; Fels, Lüder M; Fricke, Hajo Hennig; Brüning, Thomas; Wilhelm, Michael

    2002-03-10

    Male Long-Evans rats were exposed to 0 (controls) or 500 ppm trichloroethylene (TRI) for 6 months, 6 h daily, and 5 days a week. The TRI metabolites trichloroethanol (TCE) in blood and trichloroacetic acid (TCA) in urine were measured. Specific parameters related to the renal damage were determined in urine [biomarker for glomerular damage: high molecular weight proteins (HMW), albumin (ALB); for proximal tubular damage: N-acetyl-beta-D-glucosaminidase (NAG), low-molecular-weight-proteins (LMW)]. Significantly increased concentrations of NAG and LMW in urine of exposed rats were detected. No DNA-strand breaks in kidney cells could be detected using the comet assay, and histological examinations were performed. Histological alterations were observed in glomeruli and tubuli of exposed rats. The release of biomarkers for nephrotoxicity suggested alterations preferably in the proximal tubules of the exposed rats. PMID:11869834

  16. Biodegradation of vapor phase trichloroethylene (TCE) in compost packed biofilters

    SciTech Connect

    Sukesan, S.; Watwood, M.E.

    1996-10-01

    Batch and column scale biofiltration experiments were performed to measure biodegradation of gaseous trichloroethylene (TCE) in finished compost. Compost was amended with hydrocarbon gas (methane or propane) as primary substrate to support microorganisms capable of cometabolic TCE degradation. In column biofilter experiments hydrocarbon utilization was observed within 10-15 days; gaseous TCE (50 ppmv) was then introduced continuously into the biofilter at approximately 1 L min{sup -1}. Columns supplied with 0.5% v/v methane removed 73% TCE after 8 days of continuous column operation, whereas amendment with 0.25% v/v methane corresponded with TCE removal of 93%, which was observed after 1.5 h of column operation. Similar results were obtained for propane amendment. Biofilters without hydrocarbon amendment exhibited no TCE biodegradation over 35 days. These results, analyzed together with those obtained in batch experiments, indicate that hydrocarbon identity and concentration and other related parameters influence the extent of ICE breakdown.

  17. Carbon Nanotube Based Groundwater Remediation: The Case of Trichloroethylene.

    PubMed

    Jha, Kshitij C; Liu, Zhuonan; Vijwani, Hema; Nadagouda, Mallikarjuna; Mukhopadhyay, Sharmila M; Tsige, Mesfin

    2016-01-01

    Adsorption of chlorinated organic contaminants (COCs) on carbon nanotubes (CNTs) has been gaining ground as a remedial platform for groundwater treatment. Applications depend on our mechanistic understanding of COC adsorption on CNTs. This paper lays out the nature of competing interactions at play in hybrid, membrane, and pure CNT based systems and presents results with the perspective of existing gaps in design strategies. First, current remediation approaches to trichloroethylene (TCE), the most ubiquitous of the COCs, is presented along with examination of forces contributing to adsorption of analogous contaminants at the molecular level. Second, we present results on TCE adsorption and remediation on pure and hybrid CNT systems with a stress on the specific nature of substrate and molecular architecture that would contribute to competitive adsorption. The delineation of intermolecular interactions that contribute to efficient remediation is needed for custom, scalable field design of purification systems for a wide range of contaminants. PMID:27455218

  18. Dioxinlike properties of a trichloroethylene combustion-generated aerosol

    SciTech Connect

    Villalobos, S.A.; Anderson, M.J.; Hinton, D.E.

    1996-07-01

    Conventional chemical analyses of incineration by-products identify compounds of known toxicity but often fail to indicate the presence of other chemicals that may pose health risks. In a previous report, extracts from soot aerosols formed during incomplete combustion of trichloroethylene (TCE) and pyrolysis of plastics exhibited a dioxinlike response when subjected to a keratinocyte assay. To verify this dioxinlike effect, the complete extract, its polar and nonpolar fractions, some containing primarily halogenated aromatic hydrocarbons, were evaluated for toxicity using an embryo assay, for antiestrogenicity using primary liver cell cultures, and for the ability to transform the aryl hydrocarbon receptor into its DNA binding form using liver cytosol in a gel retardation assay. Each of these assays detect dioxinlike effects. Medaka (Oryzias latipes) embryos and primary liver cell cultures of rainbow trout (Oncorhynchus mykiss) were exposed to concentrations of extract ranging from 0.05 to 45 {mu}g/l. 67 refs., 7 figs., 3 tabs.

  19. Health assessment for Metal Working Shop Site, Lake Ann, Michigan, Region 5. CERCLIS No. MID980992952. Preliminary report

    SciTech Connect

    Not Available

    1988-09-30

    The Metal Working Shop Site is listed on the National Priorities List. The site consists of an operating metal-working facility in a sparsely populated rural area in Benzie, Michigan. Identified contaminants of potential concern on the site include chromium, tetrachloroethylene (PCE), trichloroethane, and toluene in water and trichloroethylene (TCE), trichloroethane, xylenes, ethylbenzene, and toluene in soil. The site is considered to be of potential public health concern because of the risk to human health caused by the possibility of exposure to hazardous substances via contaminated well water and soil. Confirmation of sampling results that show contamination in well water and soil is needed.

  20. Detailed mechanism of toluene oxidation and comparison with benzene

    NASA Technical Reports Server (NTRS)

    Bittker, David A.

    1988-01-01

    A detailed mechanism for the oxidation of toluene in both argon and nitrogen dilutents is presented. The mechanism was used to compute experimentally ignition delay times for shock-heated toluene-oxygen-argon mixtures with resonably good success over a wide range of initial temperatures and pressures. Attempts to compute experimentally measured concentration profiles for toluene oxidation in a turbulent reactor were partially successful. An extensive sensitivity analysis was performed to determine the reactions which control the ignition process and the rates of formation and destruction of various species. The most important step was found to be the reaction of toluene with molecular oxygen, followed by the reactions of hydroperoxyl and atomic oxygen with benzyl radicals. These findings contrast with the benzene oxidation, where the benzene-molecular oxygen reaction is quite unimportant and the reaction of phenyl with molecular oxygen dominates. In the toluene mechanism the corresponding reaction of benzyl radicals with oxygen is unimportant. Two reactions which are important in the oxidation of benzene also influence the oxidation of toluene for several conditions. These are the oxidations of phenyl and cyclopentadienyl radicals by molecular oxygen. The mechanism presented successfully computes the decrease of toluene concentration with time in the nitrogen diluted turbulent reactor. This fact, in addition to the good prediction of ignition delay times, shows that this mechanism can be used for modeling the ignition and combustion process in practical, well-mixed combustion systems.

  1. Remediation of trichloroethylene by bio-precipitated and encapsulated palladium nanoparticles in a fixed bed reactor.

    PubMed

    Hennebel, Tom; Verhagen, Pieter; Simoen, Henri; De Gusseme, Bart; Vlaeminck, Siegfried E; Boon, Nico; Verstraete, Willy

    2009-08-01

    Trichloroethylene is a toxic and recalcitrant groundwater pollutant. Palladium nanoparticles bio-precipitated on Shewanella oneidensis were encapsulated in polyurethane, polyacrylamide, alginate, silica or coated on zeolites. The reactivity of these bio-Pd beads and zeolites was tested in batch experiments and trichloroethylene dechlorination followed first order reaction kinetics. The calculated k-values of the encapsulated catalysts were a factor of six lower compared to non-encapsulated bio-Pd. Bio-Pd, used as a catalyst, was able to dechlorinate 100 mgL(-1) trichloroethylene within a time period of 1h. The main reaction product was ethane; yet small levels of chlorinated intermediates were detected. Subsequently polyurethane cubes empowered with bio-Pd were implemented in a fixed bed reactor for the treatment of water containing trichloroethylene. The influent recycle configuration resulted in a cumulative removal of 98% after 22 h. The same reactor in a flow through configuration achieved removal rates up to 1059 mg trichloroethylene g Pd(-1)d(-1). This work showed that fixed bed reactors with bio-Pd polyurethane cubes can be instrumental for remediation of water contaminated with trichloroethylene. PMID:19560796

  2. Reductive dehalogenation of chlorinated benzenes and toluenes under methanogenic conditions.

    PubMed Central

    Ramanand, K; Balba, M T; Duffy, J

    1993-01-01

    The anaerobic metabolism of chlorinated benzenes and toluenes was evaluated in soil slurry microcosms under methanogenic conditions. A mixture of hexachlorobenzene, pentachlorobenzene, and 1,2,4-trichlorobenzene (TCB) in soil slurries was biotransformed through sequential reductive dechlorination to chlorobenzene (CB). The metabolic pathway for hexachlorobenzene and pentachlorobenzene decay proceeded via 1,2,3,4-tetrachlorobenzene (TTCB)-->1,2,3-TCB + 1,2,4-TCB-->1,2-dichlorobenzene (DCB) + 1,4-DCB-->CB. In a mineral salts medium, the CB-adapted soil microorganisms dehalogenated individual 1,2,4,5-TTCB, 1,2,3,4-TTCB, 1,2,3-TCB, and 1,2,4-TCB but not 1,2,3,5-TTCB or 1,3,5-TCB. Similarly, a mixture of 2,3,6-trichlorotoluene (TCT), 2,5-dichlorotoluene (DCT), and 3,4-DCT was reductively dechlorinated in soil slurries to predominantly toluene and small amounts of 2-, 3-, and 4-chlorotoluene (CT). Toluene was further degraded. When tested individually in a mineral salts medium, the CT-adapted soil microorganisms dechlorinated several TCT and DCT isomers. Key metabolic routes for TCTs followed: 2,3,6-TCT-->2,5-DCT-->2-CT-->toluene; 2,4,5-TCT-->2,5-DCT + 3,4-DCT-->3-CT + 4-CT-->toluene. Among DCTs tested, 2,4-DCT and 3,4-DCT were dechlorinated via the removal of o- and m-chlorine, respectively, to 4-CT and subsequently to toluene via p-chlorine removal. Likewise, 2,5-DCT was dechlorinated via 2-CT to toluene. Evidently, microorganisms capable of removing o-, m-, and p-chlorines are present in the soil system, as reflected by the dechlorination of different isomers of CBs and CTs to CB and toluene, respectively. These findings help clarify the metabolic fate of chlorinated benzenes and toluenes in anaerobic environments. PMID:8250553

  3. Transformation of toluene and benzene by mixed methanogenic cultures.

    PubMed Central

    Grbić-Galić, D; Vogel, T M

    1987-01-01

    The aromatic hydrocarbons toluene and benzene were anaerobically transformed by mixed methanogenic cultures derived from ferulic acid-degrading sewage sludge enrichments. In most experiments, toluene or benzene was the only semicontinuously supplied carbon and energy source in the defined mineral medium. No exogenous electron acceptors other than CO2 were present. The cultures were fed 1.5 to 30 mM unlabeled or 14C-labeled aromatic substrates (ring-labeled toluene and benzene or methyl-labeled toluene). Gas production from unlabeled substrates and 14C activity distribution in products from the labeled substrates were monitored over a period of 60 days. At least 50% of the substrates were converted to CO2 and methane (greater than 60%). A high percentage of 14CO2 was recovered from the methyl group-labeled toluene, suggesting nearly complete conversion of the methyl group to CO2 and not to methane. However, a low percentage of 14CO2 was produced from ring-labeled toluene or from benzene, indicating incomplete conversion of the ring carbon to CO2. Anaerobic transformation pathways for unlabeled toluene and benzene were studied with the help of gas chromatography-mass spectrometry. The intermediates detected are consistent with both toluene and benzene degradation via initial oxidation by ring hydroxylation or methyl oxidation (toluene), which would result in the production of phenol, cresols, or aromatic alcohol. Additional reactions, such as demethylation and ring reduction, are also possible. Tentative transformation sequences based upon the intermediates detected are discussed. PMID:3105454

  4. Determination of toluene hydrogenation kinetics with neutron diffraction.

    PubMed

    Falkowska, Marta; Chansai, Sarayute; Manyar, Haresh G; Gladden, Lynn F; Bowron, Daniel T; Youngs, Tristan G A; Hardacre, Christopher

    2016-06-29

    Total neutron scattering has been used to follow the hydrogenation of toluene-d8 to methylcyclohexane-d14 over 3 wt% platinum supported on highly ordered mesoporous silica (MCM-41) at 298 K and under 150 mbar D2 pressure. The detailed kinetic information so revealed indicates that liquid reorganisation inside pores is the slowest step of the whole process. Additionally, the results were compared with the reaction performed under 250 mbar D2 pressure as well as with toluene-h8 hydrogenation using D2 at 150 mbar. PMID:27052196

  5. Effects of dynamic redox zonation on the potential for natural attenuation of trichloroethylene at a fire-training-impacted aquifer

    USGS Publications Warehouse

    Skubal, K.L.; Haack, S.K.; Forney, L.J.; Adriaens, P.

    1999-01-01

    Hydrogeochemical and microbiological methods were used to characterize temporal changes along a transect of an aquifer contaminated by mixed hydrocarbon and solvent wastes from fire training activities at Wurtsmith Air Force Base (Oscoda, MI). Predominant terminal electron accepting processes (TEAPs) as measured by dissolved hydrogen indicated reoxygenation along the transect between October 1995 and October 1996, possibly because of recharge, fluctuations in water table elevation, or microbial activity. Microbiological analyses using universal and archaeal probes revealed a relationship between groundwater hydrogen concentration, TEAP, and predominant bacterial phylogeny. Specifically, a raised water table level and evidence of methanogenesis corresponded to an order of magnitude increase in archaeal 16S rRNA relative to when this zone was unsaturated. Spatial microbial and geochemical dynamics did not result in measurable differences in trichloroethylene (TCE) mineralization potential in vadose, capillary fringe, and saturated zone soils during a 500-day microcosm experiment using unprocessed contaminated soil and groundwater. Aerobic systems indicated that methane, but not toluene, may serve as cosubstrate for TCE cometabolism. Anaerobic microcosms demonstrated evidence for methanogenesis, CO2 production and hydrogen consumption, yet dechlorination activity was only observed in a microcosm with sulfate-reduction as the dominant TEAP. Mass balance calculations indicated less than 5% mineralization, regardless of redox zone or degree of saturation, at maximum rates of 0.01-0.03 ??mol/g soil??d. The general lack of dechlorination activity under laboratory conditions corroborates the limited evidence for natural dechlorination at this site, despite abundant electron donor material and accumulated organic acids from microbial degradation of alkylbenzenes. Thus, the short-term temporal dynamics in redox conditions is unlikely to have measurable effects on the long

  6. Rheology of asphaltene-toluene/water interfaces.

    PubMed

    Sztukowski, Danuta M; Yarranton, Harvey W

    2005-12-01

    The stability of water-in-crude oil emulsions is frequently attributed to a rigid asphaltene film at the water/oil interface. The rheological properties of these films and their relationship to emulsion stability are ill defined. In this study, the interfacial tension, elastic modulus, and viscous modulus were measured using a drop shape analyzer for model oils consisting of asphaltenes dissolved in toluene for concentrations varying from 0.002 to 20 kg/m(3). The effects of oscillation frequency, asphaltene concentration, and interface aging time were examined. The films exhibited viscoelastic behavior. The total modulus increased as the interface aged at all asphaltene concentrations. An attempt was made to model the rheology for the full range of asphaltene concentration. The instantaneous elasticity was modeled with a surface equation of state (SEOS), and the elastic and viscous moduli, with the Lucassen-van den Tempel (LVDT) model. It was found that only the early-time data could be modeled using the SEOS-LVDT approach; that is, the instantaneous, elastic, and viscous moduli of interfaces aged for at most 10 minutes. At longer interface aging times, the SEOS-LVDT approach was invalid, likely because of irreversible adsorption of asphaltenes on the interface and the formation of a network structure. PMID:16316096

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

    PubMed Central

    Spence, Lisa A; Aschengrau, Ann; Gallagher, Lisa E; Webster, Thomas F; Heeren, Timothy C; Ozonoff, David M

    2008-01-01

    Background From May 1968 through March 1980, vinyl-lined asbestos-cement (VL/AC) water distribution pipes were installed in New England to avoid taste and odor problems associated with asbestos-cement pipes. The vinyl resin was applied to the inner pipe surface in a solution of tetrachloroethylene (perchloroethylene, PCE). Substantial amounts of PCE remained in the liner and subsequently leached into public drinking water supplies. Methods Once aware of the leaching problem and prior to remediation (April-November 1980), Massachusetts regulators collected drinking water samples from VL/AC pipes to determine the extent and severity of the PCE contamination. This study compares newly obtained historical records of PCE concentrations in water samples (n = 88) with concentrations estimated using an exposure model employed in epidemiologic studies on the cancer risk associated with PCE-contaminated drinking water. The exposure model was developed by Webler and Brown to estimate the mass of PCE delivered to subjects' residences. Results The mean and median measured PCE concentrations in the water samples were 66 and 0.5 μg/L, respectively, and the range extended from non-detectable to 2432 μg/L. The model-generated concentration estimates and water sample concentrations were moderately correlated (Spearman rank correlation coefficient = 0.48, p < 0.0001). Correlations were higher in samples taken at taps and spigots vs. hydrants (ρ = 0.84 vs. 0.34), in areas with simple vs. complex geometry (ρ = 0.51 vs. 0.38), and near pipes installed in 1973–1976 vs. other years (ρ = 0.56 vs. 0.42 for 1968–1972 and 0.37 for 1977–1980). Overall, 24% of the variance in measured PCE concentrations was explained by the model-generated concentration estimates (p < 0.0001). Almost half of the water samples had undetectable concentrations of PCE. Undetectable levels were more common in areas with the earliest installed VL/AC pipes, at the beginning and middle of VL/AC pipes, at

  8. Atmospheric analyzer, carbon monoxide monitor and toluene diisocyanate monitor

    NASA Technical Reports Server (NTRS)

    Shannon, A. V.

    1977-01-01

    The purpose of the atmospheric analyzer and the carbon monoxide and toluene diisocyanate monitors is to analyze the atmospheric volatiles and to monitor carbon monoxide and toluene diisocyanate levels in the cabin atmosphere of Skylab. The carbon monoxide monitor was used on Skylab 2, 3, and 4 to detect any carbon monoxide levels above 25 ppm. Air samples were taken once each week. The toluene diisocyanate monitor was used only on Skylab 2. The loss of a micrometeoroid shield following the launch of Skylab 1 resulted in overheating of the interior walls of the Orbital Workshop. A potential hazard existed from outgassing of an isocyanate derivative resulting from heat-decomposition of the rigid polyurethane wall insulation. The toluene diisocyanate monitor was used to detect any polymer decomposition. The atmospheric analyzer was used on Skylab 4 because of a suspected leak in the Skylab cabin. An air sample was taken at the beginning, middle, and the end of the mission.

  9. Elastic scattering of low-energy electrons from toluene

    NASA Astrophysics Data System (ADS)

    Sakaamini, Ahmad; Hargreaves, L. R.; Khakoo, M. A.; Pastega, D. F.; Bettega, M. H. F.

    2016-04-01

    Theoretical and normalized experimental differential, momentum transfer, and integral cross sections for vibrationally elastic scattering of low-energy electrons from toluene (C6H5C H3 ) are presented. The differential cross sections are measured at incident energies from 1 to 20 eV and scattering angles from 15° to 130°. The calculated cross sections are obtained using the Schwinger multichannel method with pseudopotentials in the static-exchange plus polarization approximation. Comparisons are made between the present theory and measurements with earlier available measurements. In general, the agreement between the theory and the experiment is very good. We also discuss the resonance spectra of toluene, where we find three π* shape resonances whose locations agree well with the experiment. In addition, we compare the cross sections of toluene and benzene, since the former can be considered as a benzene derivative by the substitution of a hydrogen in benzene by a C H3 group in toluene.

  10. 78 FR 37818 - Request for Information on Toluene Diisocyanates

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-24

    ... published a Current Intelligence Bulletin on toluene diisocyanate (TDI) and toluenediamine (TDA) [DHHS (NIOSH) Publication No. 90-101] which classified TDI and TDA (used in the manufacturing of TDI)...

  11. Gamma radiolysis of toluene and deuterated toluenes—I. Isotopic exchange

    NASA Astrophysics Data System (ADS)

    Sagert, Norman H.; MacFarlane, Roy; Kremers, Walter

    The γ radiolysis of liquid toluene and toluene-d 8 was studied at 50°C. For toluene, product yields were 0.14 molecules of hydrogen, 0.006 of methane, 0.090 of biphenyl and 0.9 of "polymer" for each 100 eV absorbed. For toluene-d 8, these yields are lower by a factor of two to three. Radiolysis of mixtures of toluene and toluene-d 8 shows a disproportionately high decomposition of the light toluene, suggesting that energy initially absorbed in toluene-d 8 transfers to toluene before decomposition occurs. Deuterium tracer studies indicate that about 14% of the hydrogen arises from unimolecular processes, whereas none of the methane or bibenzyl arises in this way. Studies using an electron scavenger, ethyl bromide, and a proton scavenger, ethanol, showed that the hydrogen yield did not likely have long-lived electrons or ions as precursors. Thus the energy transfer from toluene-d 8 to toluene is probably by direct excitation transfer, and not by charge transfer.

  12. Predicting toluene degradation in organic Rankine-cycle engines

    SciTech Connect

    Cole, R.L.; Demirgian, J.C.; Allen, J.W.

    1987-01-01

    This paper describes the measurement of toluene degradation in dynamic loop tests that simulate operation of an organic Rankine-cycle engine. Major degradation products and degradation mechanisms are identified, and degradation is quantified. Results indicate that toluene is a stable fluid with benign degradation products, provided that oxygen is excluded from the engine. A means of predicting degradation in the engine is developed. 3 refs., 4 figs., 5 tabs.

  13. Pseudomonas putida which can grow in the presence of toluene

    SciTech Connect

    Inoue, Akira; Yamamoto, Mami; Horikoshi, Koki )

    1991-05-01

    A Pseudomonas putida strain able to grow in the presence of more than 50% toluene was isolated from soil. The strain was tolerant of other toxic solvents, including aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, alcohols, and ethers. The stability of the solvent tolerance of strain IH-2,000 was stimulated by addition of Mg{sup 2+} and Ca{sup 2+} to the medium containing toluene.

  14. Toluene Diffusion and Reaction in Unsaturated Pseudomonas putida Biofilms

    PubMed Central

    Holden, Patricia A.; Hunt, James R.; Firestone, Mary K.

    2010-01-01

    Biofilms are frequently studied in the context of submerged or aquatic systems. However, much less is known about biofilms in unsaturated systems, despite their importance to such processes as food spoilage, terrestrial nutrient cycling, and biodegradation of environmental pollutants in soils. Using modeling and experimentation, we have described the biodegradation of toluene in unsaturated media by bacterial biofilms as a function of matric water potential, a dominant variable in unsaturated systems. We experimentally determined diffusion and kinetic parameters for Pseudomonas putida biofilms, then predicted biodegradation rates over a range of matric water potentials. For validation, we measured the rate of toluene depletion by intact biofilms and found the results to reasonably follow the model predictions. The diffusion coefficient for toluene through unsaturated P. putida biofilm averaged 1.3 × 10−7 cm2/s, which is approximately two orders of magnitude lower than toluene diffusivity in water. Our studies show that, at the scale of the microbial biofilm, the diffusion of toluene to biodegrading bacteria can limit the overall rate of biological toluene depletion in unsaturated systems. PMID:18642338

  15. Reproductive and developmental toxicity of toluene: a review.

    PubMed

    Donald, J M; Hooper, K; Hopenhayn-Rich, C

    1991-08-01

    Toluene is a widely used industrial solvent, and humans may also have high exposures to toluene from the deliberate inhalation ("sniffing") of paint reducer, paint thinner, or paint for their narcotic effects. A number of case reports describe neonatal effects that have been attributed to toluene abuse during pregnancy. These effects may include intrauterine growth retardation, premature delivery, congenital malformations, and postnatal developmental retardation. The possibility of exposures to other fetotoxic agents, either as impurities or admixtures in toluene-containing products, or by deliberate or accidental exposures to other chemicals or drugs, cannot be excluded in these cases. The fetotoxic effects of toluene have been demonstrated in controlled studies in animals and are comparable to those observed in humans who have abused toluene-containing products before or during pregnancy. Intrauterine developmental retardation is the most clearly established effect in animals, as evidenced by decreased late fetal weight and retarded skeletal development. There is also limited evidence in rodents for skeletal and kidney abnormalities, as well as some evidence for effects on postnatal physical and possibly neurobehavioral development. Estimated daily exposures from experimental studies in animals are compared to estimated human daily intakes at the occupational permissible exposure level and at the level reported to produce euphoria in humans. Acceptable human intakes under California's Proposition 65 and under U.S. Environmental Protection Agency procedures are discussed. PMID:1954933

  16. Toluene diffusion and reaction in unsaturated Pseudomonas putida biofilms

    SciTech Connect

    Holden, P.A.; Hunt, J.R.; Firestone, M.K.

    1997-12-20

    Biofilms are frequently studied in the context of submerged or aquatic systems. However, much less is known about biofilms in unsaturated systems, despite their importance to such processes as food spoilage, terrestrial nutrient cycling, and biodegradation of environmental pollutants in soils. Using modeling and experimentation, the authors have described the biodegradation of toluene in unsaturated media by bacterial biofilms as a function of matric water potential, a dominant variable in unsaturated systems. They experimentally determined diffusion and kinetic parameters for Pseudomonas putida biofilms, then predicted biodegradation rates over a range of matric water potentials. For validation, the authors measured the rate of toluene depletion by intact biofilms and found the results to reasonably follow the model predictions. The diffusion coefficient for toluene through unsaturated P. putida biofilm averaged 1.3 {times} 10{sup {minus}7} cm{sup 2}/s, which is approximately two orders of magnitude lower than toluene diffusivity in water. Their studies show that, at the scale of the microbial biofilm, the diffusion of toluene to biodegrading bacteria can limit the overall rate of biological toluene depletion in unsaturated systems.

  17. Physiologically-based pharmacokinetic (PBPK) modeling of two binary mixtures: metabolic activation of carbon tetrachloride by trichloroethylene and metabolic inhibition of chloroform by trichloroethylene.

    EPA Science Inventory

    The interaction between trichloroethylene (TCE) and chloroform (CHCI3) has been described as less than additive, with co-exposure to TCE and CHC13 resulting in less hepatic and renal toxicity than observed with CHCl3 alone. In contrast, the nonadditive interaction between TCE and...

  18. Modes of action of trichloroethylene for kidney tumorigenesis.

    PubMed Central

    Lash, L H; Parker, J C; Scott, C S

    2000-01-01

    This article focuses on the various models for kidney toxicity due to trichloroethylene (TCE) and its glutathione-dependent metabolites, in particular S-(1,2-dichlorovinyl)-l-cysteine. Areas of controversy regarding the relative importance of metabolic pathways, species differences in toxic responses, rates of generation of reactive metabolites, and dose-dependent phenomena are highlighted. The first section briefly reviews information on the incidence and risk factors of kidney cancer in the general U.S. population. Epidemiological data on incidence of kidney cancer in male workers exposed occupationally to TCE are also summarized. This is contrasted with cancer bioassay data from laboratory animals, that highlights sex and species differences and, consequently, the difficulties in making risk assessments for humans based on animal data. The major section of the article considers proposed modes of action for TCE or its metabolites in kidney, including peroxisome proliferation, alpha(2u)-globulin nephropathy, genotoxicity, and acute and chronic toxicity mechanisms. The latter comprise oxidative stress, alterations in calcium ion homeostasis, mitochondrial dysfunction, protein alkylation, cellular repair processes, and alterations in gene expression and cell proliferation. Finally, the status of risk assessment for TCE based on the kidneys as a target organ and remaining questions and research needs are discussed. PMID:10807554

  19. Optimization of electrochemical dechlorination of trichloroethylene in reducing electrolytes

    PubMed Central

    Mao, Xuhui; Ciblak, Ali; Baek, Kitae; Amiri, Mohammad; Loch-Caruso, Rita; Alshawabkeh, Akram N.

    2012-01-01

    Electrochemical dechlorination of trichloroethylene (TCE) in aqueous solution is investigated in a closed, liquid-recirculation system. The anodic reaction of cast iron generates ferrous species, creating a chemically reducing electrolyte (negative ORP value). The reduction of TCE on the cathode surface is enhanced under this reducing electrolyte because of the absence of electron competition. In the presence of the iron anode, the performances of different cathodes are compared in a recirculated electrolysis system. The copper foam shows superior capability for dechlorination of aqueous TCE. Electrolysis by cast iron anode and copper foam cathode is further optimized though a multivariable experimental design and analysis. The conductivity of the electrolyte is identified as an important factor for both final elimination efficiency (FEE) of TCE and specific energy consumption. The copper foam electrode exhibits high TCE elimination efficiency in a wide range of initial TCE concentration. Under coulostatic conditions, the optimal conditions to achieve the highest FEE are 9.525 mm thick copper foam electrode, 40 mA current and 0.042 mol L−1 Na2SO4. This novel electrolysis system is proposed to remediate groundwater contaminated by chlorinated organic solvents, or as an improved iron electrocoagulation process capable of treating the wastewater co-contaminated with chlorinated compounds. PMID:22264798

  20. Key Scientific Issues in the Health Risk Assessment of Trichloroethylene

    PubMed Central

    Chiu, Weihsueh A.; Caldwell, Jane C.; Keshava, Nagalakshmi; Scott, Cheryl Siegel

    2006-01-01

    Trichloroethylene (TCE) is a common environmental contaminant at hazardous waste sites and in ambient and indoor air. Assessing the human health risks of TCE is challenging because of its inherently complex metabolism and toxicity and the widely varying perspectives on a number of critical scientific issues. Because of this complexity, the U.S. Environmental Protection Agency (EPA) drew upon scientific input and expertise from a wide range of groups and individuals in developing its 2001 draft health risk assessment of TCE. This scientific outreach, which was aimed at engaging a diversity of perspectives rather than developing consensus, culminated in 2000 with 16 state-of-the-science articles published together as an Environmental Health Perspectives supplement. Since that time, a substantial amount of new scientific research has been published that is relevant to assessing TCE health risks. Moreover, a number of difficult or controversial scientific issues remain unresolved and are the subject of a scientific consultation with the National Academy of Sciences coordinated by the White House Office of Science and Technology Policy and co-sponsored by a number of federal agencies, including the U.S. EPA. The articles included in this mini-monograph provide a scientific update on the most prominent of these issues: the pharmacokinetics of TCE and its metabolites, mode(s) of action and effects of TCE metabolites, the role of peroxisome proliferator–activated receptor in TCE toxicity, and TCE cancer epidemiology. PMID:16966103

  1. Reductive dehalogenation of trichloroethylene using zero-valent iron

    SciTech Connect

    Gotpagar, J.; Grulke, E.; Bhattacharyya, D.

    1997-12-31

    Reductive dehalogenation of hazardous organics using zero-valent metals is a promising technology. The purpose of this study was to examine the effect of feed concentration, initial pH, metal loading and particle size of metal on the degradation of trichloroethylene (TCE), using zero-valent iron. The degradation rate was found to be first order with respect to the organic molecule, thus the conversion was independent of initial TCE concentration. The amount of TCE degraded at any given time was found to be directly proportional to the dissolved iron in solution. The metal surface area plays a crucial role in the process. Twofold increase in the pseudo first order rate constant was obtained when the metal particle size was decreased from 370 {mu}m by factor of 2.5. For iron surface area per unit volume (S/V) of solution < 1000 m{sup -1}, the TCE degradation rate constant increased linearly with S/V ratio. 20 refs., 8 figs., 1 tab.

  2. Cometabolic degradation of trichloroethylene in a bubble column bioscrubber.

    PubMed

    Hecht, V; Brebbermann, D; Bremer, P; Deckwer, W D

    1995-08-20

    A bubble column bioreactor was used as bioscrubber to carry out a feasibility study for the cometabolic degradation of trichloroethylene (TCE). Phenol was used as cosubstrate and inducer. The bioreactor was operated like a conventional chemostat with regard to the cosubstrate and low dilution rates were used to minimize the liquid outflow. TCE degradation measurements were carried out using superficial gas velocities between 0.47and 4.07 cm s(-1) and TCE gas phase loads between 0.07 and 0.40 mg L(-1) Depending on the superficial gas velocity used, degrees of conversion between 30% and 80% were obtained. A simplified reactor model using plug flow for the gas phase, mixed flow for the liquid phase, and pseudo first order reaction kinetics for the conversionof TCE was established. The model is able to give a reasonable approximation of the experimental data. TCE degradation at the used experimental conditions is mainly limited by reaction rate rather than by mass transfer rate. The model can be used to calculate the reactor volume and the biomass concentration for a required conversion. (c) 1995 John Wiley & Sons Inc. PMID:18623422

  3. Complete dissolution of trichloroethylene in saturated porous media

    SciTech Connect

    Imhoff, P.T.; Arthur, M.H.; Miller, C.T.

    1998-08-15

    Porous media containing trichloroethylene (TCE) trapped at residual saturation in otherwise water-saturated porous media were flushed with water to asses the dissolution rate of TCE as TCE volumetric fractions approached zero. Careful attention to column design and experimental methods limited the effect of column materials on effluent concentrations. Effluent concentration measurements during TCE dissolution are presented for a glass bead porous medium, a mixed sand, and a treated soil. Effluent concentrations were measured as they decreased below 5 {micro}g/L, the maximum allowable contaminant level, in the glass bead and mixed sand media. Effluent concentrations from columns packed with treated soil were measured down to 20 {micro}g/L. Solvent extraction of the treated soil after the dissolution experiments revealed that extremely small quantities of TCE were retained in this medium. Results from parallel experiments on columns exposed to only aqueous TCE suggest that TCE remaining in the treated soil columns was sorbed to the porous medium. Existing power-law models were capable of describing TCE dissolution in these media, if the exponent on the TCE volume fraction was modified appropriately.

  4. Biotransformation of trichloroethylene by a phenol-induced mixed culture

    SciTech Connect

    Shurtliff, M.M.; Parkin, G.F.; Gibson, D.T.; Weathers, L.J.

    1996-07-01

    Biodegradation of trichloroethylene (TCE) was studied using a mixed culture of aerobic, phenol-induced organisms. Abiotic experiments showed that sorption of TCE to biomass was negligible in the systems studied. The effects of influent phenol and TCE concentration on the TCE degradation capacity of the culture were studied using chemostats. A relationship exists between the influent phenol/TCE ratio and TCE biodegradation. TCE transformation yields ranged from 0.052 to 0.222 mg TCE removed/mg phenol removed. Monod kinetic coefficients for phenol degradation were determined. Monod kinetic coefficients were also determined for TCE biotransformation by resting cells. The concept of transformation capacity was used to model the decrease in active biomass concentration caused by TCE transformation. In mineralization studies using {sup 14}C-labeled TCE, 22% of the degraded mass of TCE was transformed to carbon dioxide, 8.8% was incorporated into biomass, 42% was transformed to nonvolatile products, with the remaining, unrecovered 27% most likely transformed into volatile or semivolatile products.

  5. Mass recovery methods for trichloroethylene in plant tissue.

    SciTech Connect

    Gopalakrishnan, G.; Negri, M. C.; Werth, C. J.; Energy Systems; Univ. of Illionis

    2009-06-01

    Monitoring expenses form a significant fraction of the costs associated with remediation of contaminated soil and groundwater sites. A novel monitoring method that could result in significant cost savings is the use of plants as monitoring devices; previous work indicates that plant tissue samples, especially trunk (core) and branch samples, can be used to delineate soil and groundwater plumes at phytoremediation sites. An important factor in reducing the uncertainty associated with this sampling method is development of a technique to analyze, both consistently and accurately, the chemicals stored in plant tissue samples. The present research presents a simple, robust, and inexpensive technique to recover most of the contaminant in plant branch tissue, irrespective of the age or species of the plant. Trichloroethylene (TCE) was the chemical analyzed. A number of headspace and solvent extraction techniques in the literature were evaluated, including headspace extraction at different incubation times and temperatures and solvent extraction using hexane or hot methanol. Extraction using hot methanol was relatively fast, simple, and reliable; this method recovered more than 89% of the TCE present in branches of five different tree species.

  6. Trichloroethylene: Mechanistic, Epidemiologic and Other Supporting Evidence of Carcinogenic Hazard

    PubMed Central

    Rusyn, Ivan; Chiu, Weihsueh A.; Lash, Lawrence H.; Kromhout, Hans; Hansen, Johnni; Guyton, Kathryn Z.

    2013-01-01

    The chlorinated solvent trichloroethylene (TCE) is a ubiquitous environmental pollutant. The carcinogenic hazard of TCE was the subject of a 2012 evaluation by a Working Group of the International Agency for Research on Cancer (IARC). Information on exposures, relevant data from epidemiologic studies, bioassays in experimental animals, and toxicity and mechanism of action studies was used to conclude that TCE is carcinogenic to humans (Group 1). This article summarizes the key evidence forming the scientific bases for the IARC classification. Exposure to TCE from environmental sources (including from hazardous waste sites and contaminated water) is common throughout the world. While workplace use of TCE has been declining, occupational exposures remain of concern, especially in developing countries. Strongest human evidence is from studies of occupational TCE exposure and kidney cancer. Positive, although less consistent, associations were reported for liver cancer and non-Hodgkin's lymphoma. TCE is carcinogenic at multiple sites in multiple species and strains of experimental animals. The mechanistic evidence includes extensive data on the toxicokinetics and genotoxicity of TCE and its metabolites. Together, available evidence provided a cohesive database supporting the human cancer hazard of TCE, particularly in the kidney. For other target sites of carcinogenicity, mechanistic and other data were found to be more limited. Important sources of susceptibility to TCE toxicity and carcinogenicity were also reviewed by the Working Group. In all, consideration of the multiple evidence streams presented herein informed the IARC conclusions regarding the carcinogenicity of TCE. PMID:23973663

  7. Removal of Trichloroethylene and Heavy Metals by Zerovalent Iron Nanoparticles

    NASA Astrophysics Data System (ADS)

    Boparai, H. K.; O'Carroll, D. M.

    2009-05-01

    Heavy metals combined with chlorinated solvents are one class of mixed waste found at various hazardous waste sites in North America. Nano zerovalent iron (nZVI), an emerging technology, is being successfully used for treating chlorinated solvents and heavy metals independently, however comparatively little research has investigated the remediation of the wastes when they are present in the same mixture. The remediation of trichloroethylene (TCE)/heavy metal waste mixtures via nZVI has been investigated in the present study. Results suggest that some metals are reduced by nZVI to their zerovalent state and thus precipitate on nZVI particles. This improves the contaminant removal performance of nZVI by forming bimetallic iron nanoparticles. Other metals are directly precipitated or adsorbed on the nZVI particles in their original oxidation state and are rendered immobile. In some cases the presence of the heavy metals in the waste mixture enhanced the dechlorination of TCE while in other cases it did not. This study suggests that nano zerovalent iron particles can be effectively used for the remediation of mixed contamination of heavy metals and chlorinated solvents. Results have been supported by a variety of techniques including X-ray photoelectron spectroscopy (XPS) analysis.

  8. Biodegradation of trichloroethylene and biomanipulation of aquifers. Technical report (Final)

    SciTech Connect

    Jaffe, P.R.; Taylor, S.W.; Baek, N.H.; Christopher, P.; Milly, D.

    1988-08-01

    Three distinct aspects of the biodegradation process in a porous media were addressed. The effect of the trichloroethylene(TCE) concentration on bacterial activity was investigated. The results showed that the dissolved-phase concentration directly affects the bacterial activity. For aerobic soils, LD50 for water concentrations ranged between 200-300 mg/l for CO/sub 2/ evolution, and 80 to 150 mg/l for dehydrogenase activity. The degradation of TCE and its intermediates by mixed cultures containing fermenters and methanogens was investigated. Results showed that fermenters play an important role in this process and that the degradation rate correlates with the methanogenic activity. It was shown that TCE can be degraded by these mixed cultures via 1,1-dichloroethylene to vinyl chloride, to chloroethane which is readily degradable. Kinetic rates were obtained for this degradation process and normalized with respect to the methane production. The effect of biomass production in porous media on the permeability and dispersivity was investigated. Experimental results showed that the permeability of a sandy media depends on the biomass if the biomass is less than 0.4 mg of organic carbon/cu cm, and becomes independent of the biomass for higher values. Changes in permeability and dispersivity as a function of the biofilm thickness were modeled successfully using a modified cut-and-random-rejoin-type model.

  9. A Case of Occupational Hypersensitivity Pneumonitis Associated with Trichloroethylene

    PubMed Central

    Kim, Young Jae; Hwang, Eu Dong; Leem, Ah Young; Kang, Beo Deul; Chang, Soo Yun; Kim, Ho Keun; Park, In Kyu; Kim, Song Yee; Kim, Eun Young; Jung, Ji Ye; Kang, Young Ae; Park, Moo Suk; Kim, Young Sam; Kim, Se Kyu; Chang, Joon

    2014-01-01

    Trichloroethylene (TCE) is a toxic chemical commonly used as a degreasing agent, and it is usually found in a colorless or blue liquid form. TCE has a sweet, chloroform-like odor, and this volatile chlorinated organic chemical can cause toxic hepatitis, neurophysiological disorders, skin disorders, and hypersensitivity syndromes. However, the hypersensitivity pneumonitis (HP) attributed to TCE has rarely been reported. We hereby describe a case of HP associated with TCE in a 29-year-old man who was employed as a lead welder at a computer repair center. He was installing the capacitors on computer chip boards and had been wiped down with TCE. He was admitted to our hospital with complaints of dry coughs, night sweats, and weight losses for the past two months. HP due to TCE exposure was being suspected due to his occupational history, and the results of a video-associated thoracoscopic biopsy confirmed the suspicions. Symptoms have resolved after the steroid pulse therapy and his occupational change. TCE should be taken into consideration as a potential trigger of HP. Early recognition and avoidance of the TCE exposure in the future is important for the treatment of TCE induced HP. PMID:24624216

  10. Degradation of trichloroethylene by Pseudomonas cepacia G4 and the constitutive mutant strain G4 5223 PR1 in aquifer microcosms.

    PubMed

    Krumme, M L; Timmis, K N; Dwyer, D F

    1993-08-01

    Pseudomonas cepacia G4 degrades trichloroethylene (TCE) via a degradation pathway for aromatic compounds which is induced by substrates such as phenol and tryptophan. P. cepacia G4 5223 PR1 (PR1) is a Tn5 insertion mutant which constitutively expresses the toluene ortho-monooxygenase responsible for TCE degradation. In groundwater microcosms, phenol-induced strain G4 and noninduced strain PR1 degraded TCE (20 and 50 microM) to nondetectable levels (< 0.1 microM) within 24 h at densities of 10(8) cells per ml; at lower densities, degradation of TCE was not observed after 48 h. In aquifer sediment microcosms, TCE was reduced from 60 to < 0.1 microM within 24 h at 5 x 10(8) PR1 organisms per g (wet weight) of sediment and from 60 to 26 microM over a period of 10 weeks at 5 x 10(7) PR1 organisms per g. Viable G4 and PR1 cells decreased from approximately 10(7) to 10(4) per g over the 10-week period. PMID:7690223

  11. Copper Enhanced Monooxygenase Activity and FT-IR Spectroscopic Characterisation of Biotransformation Products in Trichloroethylene Degrading Bacterium: Stenotrophomonas maltophilia PM102

    PubMed Central

    Mukherjee, Piyali; Roy, Pranab

    2013-01-01

    Stenotrophomonas maltophilia PM102 (NCBI GenBank Acc. no. JQ797560) is capable of growth on trichloroethylene as the sole carbon source. In this paper, we report the purification and characterisation of oxygenase present in the PM102 isolate. Enzyme activity was found to be induced 10.3-fold in presence of 0.7 mM copper with a further increment to 14.96-fold in presence of 0.05 mM NADH. Optimum temperature for oxygenase activity was recorded at 36°C. The reported enzyme was found to have enhanced activity at pH 5 and pH 8, indicating presence of two isoforms. Maximum activity was seen on incubation with benzene compared to other substrates like TCE, chloroform, toluene, hexane, and petroleum benzene. Km and Vmax for benzene were 3.8 mM and 340 U/mg/min and those for TCE were 2.1 mM and 170 U/mg/min. The crude enzyme was partially purified by ammonium sulphate precipitation followed by dialysis. Zymogram analysis revealed two isoforms in the 70% purified enzyme fraction. The activity stain was more prominent when the native gel was incubated in benzene as substrate in comparison to TCE. Crude enzyme and purified enzyme fractions were assayed for TCE degradation by the Fujiwara test. TCE biotransformation products were analysed by FT-IR spectroscopy. PMID:24083236

  12. Cardiorespiratory effects of outpatient anesthesia for oral surgery: trichloroethylene-halothane.

    PubMed

    Allen, G D; Everett, G B; Haines, M

    1976-12-01

    The cardiorespiratory effects of trichloroethylene supplementation of nitrous oxide-oxygen anesthesia, with simultaneous use of halothane at induction as needed, were studied in outpatient oral surgery patients undergoing dental extractions under general anesthesia. The technique produced no deleterious cardiovascular effects that could be attributed to the combined use of these agents. Elevations of blood pressure, stroke volume, and peripheral resistance indicated light anesthesia. The versatility of halothane combined with the absence of nephrotoxic and hepatotoxic breakdown products of trichloroethylene provides a satisfactory technique for outpatient oral surgery. The agents appear pharmacologically complimentary in that halothane lacks analgesic properties and postoperative shivering occurs, while induction with trichloroethylene is slow and tachypnea is a problem. PMID:1069107

  13. Water stress effects on toluene biodegradation by Pseudomonas putida.

    PubMed

    Holden, P A; Halverson, L J; Firestone, M K

    1997-01-01

    We quantified the effects of matric and solute water potential on toluene biodegradation by Pseudomonas putida mt-2, a bacterial strain originally isolated from soil. Across the matric potential range of 0 to -1.5 MPa, growth rates were maximal for P. putida at -0.25 MPa and further reductions in the matric potential resulted in concomitant reductions in growth rates. Growth rates were constant over the solute potential range 0 to -1.0 MPa and lower at -1.5 MPa. First order toluene depletion rate coefficients were highest at 0.0 MPa as compared to other matric water potentials down to -1.5 MPa. Solute potentials down to -1.5 MPa did not affect first order toluene depletion rate coefficients. Total yield (protein) and carbon utilization efficiency were not affected by water potential, indicating that water potentials common to temperate soils were not sufficiently stressful to change cellular energy requirements. We conclude that for P. putida: (1) slightly negative matric potentials facilitate faster growth rates on toluene but more negative water potentials result in slower growth, (2) toluene utilization rate per cell mass is highest without matric water stress and is unaffected by solute potential, (3) growth efficiency did not differ across the range of matric water potentials 0.0 to -1.5 MPa. PMID:9396169

  14. Performance and properties of nanoscale calcium peroxide for toluene removal.

    PubMed

    Qian, Yajie; Zhou, Xuefei; Zhang, Yalei; Zhang, Weixian; Chen, Jiabin

    2013-04-01

    Due to the large diameter and small surface, the contaminant degradation by conventional calcium peroxide (CaO2) is slow with high dosage required. The aggregation of conventional CaO2 also makes it difficult to operate. Nanoscale CaO2 was therefore synthesized and applied to remove toluene in this study. Prepared from nanoscale Ca(OH)2 and H2O2 in the ratio of 1:7, the finely dispersed nanoscale CaO2 particles were confirmed by the scanning electron microscope to be in the range of 100-200nm in size. Compared to their non nanoscale counterparts, the synthesized nanoscale CaO2 demonstrated a superior performance in the degradation of toluene, which could be eliminated in 3d at pH 6. The oxidation products of toluene were analyzed to include benzyl alcohol, benzaldehyde and three cresol isomers. With the addition of 2-propanol, hydroxyl radicals were indicated as the main reactive oxygen species in the oxidation of toluene by nanoscale CaO2. Superoxide radicals were also investigated as the marker of nanoscale CaO2 in the solution. Our study thus provides an important insight into the application of nanoscale CaO2 in the removal of toluene contaminants, which is significant, especially for controlling the petroleum contaminations. PMID:23466092

  15. Relationship between vapor intrusion and human exposure to trichloroethylene.

    PubMed

    Archer, Natalie P; Bradford, Carrie M; Villanacci, John F; Crain, Neil E; Corsi, Richard L; Chambers, David M; Burk, Tonia; Blount, Benjamin C

    2015-01-01

    Trichloroethylene (TCE) in groundwater has the potential to volatilize through soil into indoor air where it can be inhaled. The purpose of this study was to determine whether individuals living above TCE-contaminated groundwater are exposed to TCE through vapor intrusion. We examined associations between TCE concentrations in various environmental media and TCE concentrations in residents. For this assessment, indoor air, outdoor air, soil gas, and tap water samples were collected in and around 36 randomly selected homes; blood samples were collected from 63 residents of these homes. Additionally, a completed exposure survey was collected from each participant. Environmental and blood samples were analyzed for TCE. Mixed model multiple linear regression analyses were performed to determine associations between TCE in residents' blood and TCE in indoor air, outdoor air, and soil gas. Blood TCE concentrations were above the limit of quantitation (LOQ; ≥ 0.012 µg L(-1)) in 17.5% of the blood samples. Of the 36 homes, 54.3%, 47.2%, and >84% had detectable concentrations of TCE in indoor air, outdoor air, and soil gas, respectively. Both indoor air and soil gas concentrations were statistically significantly positively associated with participants' blood concentrations (P = 0.0002 and P = 0.04, respectively). Geometric mean blood concentrations of residents from homes with indoor air concentrations of >1.6 µg m(-3) were approximately 50 times higher than geometric mean blood TCE concentrations in participants from homes with no detectable TCE in indoor air (P < .0001; 95% CI 10.4-236.4). This study confirms the occurrence of vapor intrusion and demonstrates the magnitude of exposure from vapor intrusion of TCE in a residential setting. PMID:26259926

  16. Enhanced reductive dechlorination of trichloroethylene by sulfidated nanoscale zerovalent iron.

    PubMed

    Rajajayavel, Sai Rajasekar C; Ghoshal, Subhasis

    2015-07-01

    Direct injection of reactive nanoscale zerovalent iron particles (NZVI) is considered to be a promising approach for remediation of aquifers contaminated by chlorinated organic pollutants. In this study we show that the extent of sulfidation of NZVI enhances the rate of dechlorination of trichloroethylene (TCE) compared to that by unamended NZVI, and the enhancement depends on the Fe/S molar ratio. Experiments where TCE was reacted with NZVI sulfidated to different extents (Fe/S molar ratios 0.62-66) showed that the surface-area normalized first-order TCE degradation rate constant increased up to 40 folds compared to non-sulfidated NZVI. Fe/S ratios in the range of 12-25 provided the highest TCE dechlorination rates, and rates decreased at both higher and lower Fe/S. In contrast, sulfidated NZVI exposed to water in the absence of TCE showed significantly lower hydrogen evolution rate (2.75 μmol L(-1) h(-1)) compared to that by an unamended NZVI (6.92 μmol L(-1) h(-1)), indicating that sulfidation of NZVI suppressed corrosion reactions with water. Sulfide (HS(-)) ions reacted rapidly with NZVI and X-ray photoelectron spectroscopy analyses showed formation of a surface layer of FeS and FeS2. We propose that more electrons are preferentially conducted from sulfidated NZVI than from unamended NZVI to TCE, likely because of greater binding of TCE on the reactive sites of the iron sulfide outer layer. Resuspending sulfidated NZVI in sulfide-free or sulfide containing solutions altered the TCE degradation rate constants because of changes in the FeS layer thickness. Sulfidated NZVI maintained its high reactivity in the presence of multiple mono and divalent ions and with polyelectrolyte coatings. Thus, sulfide ions in groundwater can significantly alter NZVI reactivity. PMID:25935369

  17. Natural attenuation of trichloroethylene in fractured shale bedrock.

    PubMed

    Lenczewski, M; Jardine, P; McKay, L; Layton, A

    2003-07-01

    This paper describes one of the first well-documented field examples of natural attenuation of trichloroethylene (TCE) in groundwater in a fractured shale bedrock. The study was carried out adjacent to a former waste burial site in Waste Area Grouping 5 (WAG5) on the Oak Ridge Reservation, Oak Ridge, TN. A contaminant plume containing TCE and its daughter products were detected downgradient from the buried waste pits, with most of the contamination occurring in the upper 6 m of the bedrock. The monitoring well array consists of a 35-m-long transect of multilevel sampling wells, situated along a line between the waste pits and a seep which discharges into a small stream. Concentrations of volatile organic carbons (VOCs) were highest in the waste trenches and decreased with distance downgradient towards the seep. Sampling wells indicated the presence of overlapping plumes of TCE, cis-dichloroethylene (cDCE), vinyl chloride (VC), ethylene, ethane, and methane, with the daughter products extending further downgradient than the parent (TCE). This type of distribution suggests anaerobic biodegradation. Measurements of redox potential at the site indicated that iron-reduction, sulfate reduction, and potentially methanogensis were occurring and are conducive to dechlorination of TCE. Bacteria enrichment of groundwater samples revealed the presence of methanotrophs, methanogens, iron-reducing bacteria and sulfate-reducing bacteria, all of which have previously been implicated in anaerobic biodegradation of TCE. 16S rDNA sequence from DNA extracted from two wells were similar to sequences of organisms previously implicated in the anaerobic biodegradation of chlorinated solvents. The combined data strongly suggest that anaerobic biodegradation of the highly chlorinated compounds is occurring. Aerobic biodegradation may also be occurring in oxygenated zones, including near a seep where groundwater exits the site, or in the upper bedrock during seasonal fluctuations in water

  18. Conditions affecting the mutagenicity of trichloroethylene in Salmonella

    SciTech Connect

    McGregor, D.B.; Reynolds, D.M. ); Zeiger, E. )

    1989-01-01

    Trichloroethylene (TCE) is a high production volume chemical frequency stabilized with oxiranes. These oxiranes may be responsible for the mutagenic activity of TCE in Salmonella, which has been occasionally, but not consistently, reported. High purity and oxirane-stabilized TCE samples were tested for their mutagenic potential in Salmonella typhimurium strains TA 1535, TA 98, and TA 100. Stabilized TCE was tested using a preincubation protocol up to a dose level of 10,000 {mu}g per plate, but not mutagenic response was observed in either the presence or absence of a supplementary metabolic activation system (S9 mix) derived from Aroclor 1254-induced male rat liver. TCE without oxirane stabilizers also was nonmutagenic when tested in a vapor delivery system at nominal concentrations of up to 20% and using S9 mix derived from either rat or hamster. TCE containing 0.5-0.6% 1,2-epoxybutane did induce mutagenic responses from strains TA 1535 and TA 100 in the presence and absence of S9 mix. Vapor-phase tests with 1,2-epoxybutane showed that an atmospheric concentration of 0.009% could induce 12-fold and 3-fold increases, respectively, in strains TA 1535 and TA 100. These increases would account for the mutagenic activity of the stabilized TCE sample. The absence of a significant response caused by unstabilized TCE in the presence of S9 mix is probably due to a lack of assay sensitivity, since chloral, a metabolite of TCE, is a mutagen in TA 100.

  19. Impact of iron sulfide transformation on trichloroethylene degradation

    SciTech Connect

    He, Y. Thomas; Wilson, John T.; Wilkin, Richard T.

    2010-05-04

    Trichloroethylene (TCE) is one of the most common and persistent groundwater contaminants encountered at hazardous waste sites around the world. A growing body of evidence indicates that iron sulfides play an important role in degrading TCE in natural environments and in engineered systems designed for groundwater cleanup. In this study, we investigate transformation processes of iron sulfides and consequent impacts on TCE degradation using batch experimental techniques, transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray absorption spectroscopy (XAS). Our results show that mackinawite is highly reactive toward TCE and no detectable mineralogical changes were detected during the course of reaction. However, freeze-dried FeS transformed to a mixture of mackinawite and greigite during the freeze drying process, with further mineralogical changes during reaction with TCE to lepidocrocite, goethite and pyrite. Newly formed lepidocrocite is a transient phase, with conversion to goethite over time. TCE transformation kinetics show that freeze-dried FeS is 20-50 times less reactive in degrading TCE than non-freeze-dried FeS, and the TCE degradation rate increases with pH (from 5.4 to 8.3), possibly due to an increase of surface deprotonation or electron transfer at higher pH. Results suggest that freeze drying could cause FeS particle aggregation, decreased surface area and availability of reactive sites; it also could change FeS mineralogy and accelerate mineral transformation. These aspects could contribute to the lower reactivity of freeze-dried FeS toward TCE degradation. Modeling results show that FeS transformation in natural environments depends on specific biogeochemical conditions, and natural FeS transformation may affect mineral reactivity in a similar way as compared to the freeze drying process. Rapid transformation of FeS to FeS{sub 2} could significantly slow down TCE degradation in both natural and engineered systems.

  20. Impact of iron sulfide transformation on trichloroethylene degradation

    NASA Astrophysics Data System (ADS)

    He, Y. Thomas; Wilson, John T.; Wilkin, Richard T.

    2010-04-01

    Trichloroethylene (TCE) is one of the most common and persistent groundwater contaminants encountered at hazardous waste sites around the world. A growing body of evidence indicates that iron sulfides play an important role in degrading TCE in natural environments and in engineered systems designed for groundwater cleanup. In this study, we investigate transformation processes of iron sulfides and consequent impacts on TCE degradation using batch experimental techniques, transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray absorption spectroscopy (XAS). Our results show that mackinawite is highly reactive toward TCE and no detectable mineralogical changes were detected during the course of reaction. However, freeze-dried FeS transformed to a mixture of mackinawite and greigite during the freeze drying process, with further mineralogical changes during reaction with TCE to lepidocrocite, goethite and pyrite. Newly formed lepidocrocite is a transient phase, with conversion to goethite over time. TCE transformation kinetics show that freeze-dried FeS is 20-50 times less reactive in degrading TCE than non-freeze-dried FeS, and the TCE degradation rate increases with pH (from 5.4 to 8.3), possibly due to an increase of surface deprotonation or electron transfer at higher pH. Results suggest that freeze drying could cause FeS particle aggregation, decreased surface area and availability of reactive sites; it also could change FeS mineralogy and accelerate mineral transformation. These aspects could contribute to the lower reactivity of freeze-dried FeS toward TCE degradation. Modeling results show that FeS transformation in natural environments depends on specific biogeochemical conditions, and natural FeS transformation may affect mineral reactivity in a similar way as compared to the freeze drying process. Rapid transformation of FeS to FeS 2 could significantly slow down TCE degradation in both natural and engineered systems.

  1. Autoxidation of trichloroethylene in aqueous solution at groundwater contamination concentrations

    SciTech Connect

    Eisenbeis, J.J.

    1989-01-01

    Trichloroethylene (TCE), a commonly used industrial degreaser and solvent, is one of the most frequently detected contaminants of soils and groundwater. One aspect of the subsurface behavior of TCE involves the types and rates of degradation processes the various phases undergo. While biological degradation of TCE has received much recent attention in the research, very little research has been directed at autoxidation of TCE in dilute aqueous solutions at concentrations typical of subsurface contamination. Dilute aqueous solutions of TCE were examined under laboratory conditions to evaluate the kinetics of aqueous phase autoxidation. The concentrations and temperatures used were within the range of those typically found in contaminated groundwater and soils. Autoxidation was carried out in 44 ml glass reaction vials and the degradation rate was monitored by measuring the loss of TCE by gas chromatography. Results indicated that autoxidation occurred despite the addition of an antioxidant to the pure solvent by the manufacturer. Autoxidation of TCE is suspected to occur via a sequence of free radical reactions. The overall reaction order determined for the sequence was approximately 0.8. The overall reaction was found to proceed at two rates, an initial rate from 0 to 24 hours and a long term rate thereafter. The rate coefficients corresponding to these two rate thereafter. The rate coefficients corresponding to these two reaction rates were approximately 2 and 1 {times} 10{sup {minus}4}mol{sup 0.2}1{sup {minus}0.2}hr{sup {minus}1}, respectively. The rate coefficient and reaction order were used to determine an equation to calculate half life. Solutions of 10 ppb and 1 ppm were calculated to have half lives of approximately 10 days and 25 days, respectively.

  2. Human Health Effects of Trichloroethylene: Key Findings and Scientific Issues

    PubMed Central

    Jinot, Jennifer; Scott, Cheryl Siegel; Makris, Susan L.; Cooper, Glinda S.; Dzubow, Rebecca C.; Bale, Ambuja S.; Evans, Marina V.; Guyton, Kathryn Z.; Keshava, Nagalakshmi; Lipscomb, John C.; Barone, Stanley; Fox, John F.; Gwinn, Maureen R.; Schaum, John; Caldwell, Jane C.

    2012-01-01

    Background: In support of the Integrated Risk Information System (IRIS), the U.S. Environmental Protection Agency (EPA) completed a toxicological review of trichloroethylene (TCE) in September 2011, which was the result of an effort spanning > 20 years. Objectives: We summarized the key findings and scientific issues regarding the human health effects of TCE in the U.S. EPA’s toxicological review. Methods: In this assessment we synthesized and characterized thousands of epidemiologic, experimental animal, and mechanistic studies, and addressed several key scientific issues through modeling of TCE toxicokinetics, meta-analyses of epidemiologic studies, and analyses of mechanistic data. Discussion: Toxicokinetic modeling aided in characterizing the toxicological role of the complex metabolism and multiple metabolites of TCE. Meta-analyses of the epidemiologic data strongly supported the conclusions that TCE causes kidney cancer in humans and that TCE may also cause liver cancer and non-Hodgkin lymphoma. Mechanistic analyses support a key role for mutagenicity in TCE-induced kidney carcinogenicity. Recent evidence from studies in both humans and experimental animals point to the involvement of TCE exposure in autoimmune disease and hypersensitivity. Recent avian and in vitro mechanistic studies provided biological plausibility that TCE plays a role in developmental cardiac toxicity, the subject of substantial debate due to mixed results from epidemiologic and rodent studies. Conclusions: TCE is carcinogenic to humans by all routes of exposure and poses a potential human health hazard for noncancer toxicity to the central nervous system, kidney, liver, immune system, male reproductive system, and the developing embryo/fetus. PMID:23249866

  3. Trichloroethylene Metabolism in the Rat Ovary Reduces Oocyte Fertilizability

    PubMed Central

    Wu, Katherine Lily; Berger, Trish

    2007-01-01

    Exposure to trichloroethylene (TCE, an environmental toxicant) reduced oocyte fertilizability in the rat. In vivo, TCE may be metabolized by cytochrome P450 dependent oxidation or glutathione conjugation in the liver or kidneys, respectively. Cytochrome P450 dependent oxidation is the higher affinity pathway. The primary isoform of cytochrome P450 to metabolize TCE in the liver, cytochrome P450 2E1, is present in the rodent ovary. Ovarian metabolism of TCE by the oxidative pathway and the production of reactive oxygen species may occur given the presence of the metabolizing enzyme. The objectives of this study were to define the sensitive interval of oocyte growth to TCE exposure, and to determine if TCE exposure resulted in the formation of ovarian protein carbonyls, an indicator of oxidative damage. Rats were exposed to TCE in drinking water (0.45% TCE (v/v) in 3% Tween) or 3% Tween (vehicle-control) during three 4–5 day intervals of oocyte development preceding ovulation. Oocytes from TCE-exposed females were less fertilizable compared with vehicle-control oocytes. Immunohistochemical labeling of ovaries and Western blotting of ovarian proteins demonstrated TCE treatment induced a greater incidence of protein carbonyls compared with vehicle controls. Protein carbonyl formation in the ovary is consistent with TCE metabolism by the cytochrome P450 pathway. Oxidative damage following ovarian TCE metabolism or the presence of TCE metabolites may contribute to reduced oocyte fertilizability. In summary, these results indicate maturing oocytes are susceptible to very short in vivo exposures to TCE. PMID:17673192

  4. Linking Toluene Degradation with Specific Microbial Populations in Soil

    PubMed Central

    Hanson, Jessica R.; Macalady, Jennifer L.; Harris, David; Scow, Kate M.

    1999-01-01

    Phospholipid fatty acid (PLFA) analysis of a soil microbial community was coupled with 13C isotope tracer analysis to measure the community’s response to addition of 35 μg of [13C]toluene ml of soil solution−1. After 119 h of incubation with toluene, 96% of the incorporated 13C was detected in only 16 of the total 59 PLFAs (27%) extracted from the soil. Of the total 13C-enriched PLFAs, 85% were identical to the PLFAs contained in a toluene-metabolizing bacterium isolated from the same soil. In contrast, the majority of the soil PLFAs (91%) became labeled when the same soil was incubated with [13C]glucose. Our study showed that coupling 13C tracer analysis with PLFA analysis is an effective technique for distinguishing a specific microbial population involved in metabolism of a labeled substrate in complex environments such as soil. PMID:10583996

  5. Incineration of toluene and chlorobenzene in a laboratory incinerator

    SciTech Connect

    Mao, Z.; Mcintosh, M.J.; Demirgian, J.C.

    1992-01-01

    This paper reports experimental results on the incineration of toluene and chlorobenzene in a small laboratory incinerator. Temperature of the incinerator, excess air ratio and mean residence time were varied to simulate both complete and incomplete combustion conditions. The flue gas was monitored on line using Fourier transform infrared (FTIR) spectroscopy coupling with a heated long path cell (LPC). Methane, toluene, benzene, chlorobenzene, hydrogen chloride and carbon monoxide in the flue gas were simultaneously analyzed. Experimental results indicate that benzene is a major product of incomplete combustion (PIC) besides carbon monoxide in the incineration of toluene and chlorobenzene, and is very sensitive to combustion conditions. This suggests that benzene is a target analyle to be monitored in full-scale incinerators.

  6. Incineration of toluene and chlorobenzene in a laboratory incinerator

    SciTech Connect

    Mao, Zhuoxiong; McIntosh, M.J.; Demirgian, J.C.

    1992-01-01

    This paper reports results on incineration of toluene and chlorobenzene in a small laboratory incinerator. The incinerator temperature, excess air ratio and mean residence time were varied to simulate both complete and incomplete combustion conditions. The flue gas was monitored on line using Fourier transform infrared (FTIR) spectroscopy coupling with a heated long path cell (LPC). Methane, toluene, benzene, chlorobenzene, hydrogen chloride and carbon monoxide in the flue gas were simultaneously analyzed. Experimental results indicate that benzene is a major product of incomplete combustion (PIC), besides carbon monoxide, in the incineration of toluene and chlorobenzene and is very sensitive to the combustion conditions. This suggests that benzene is a target analyte to be monitored in full-scale incinerators.

  7. Incineration of toluene and chlorobenzene in a laboratory incinerator

    SciTech Connect

    Mao, Zhuoxiong; McIntosh, M.J.; Demirgian, J.C.

    1992-12-31

    This paper reports results on incineration of toluene and chlorobenzene in a small laboratory incinerator. The incinerator temperature, excess air ratio and mean residence time were varied to simulate both complete and incomplete combustion conditions. The flue gas was monitored on line using Fourier transform infrared (FTIR) spectroscopy coupling with a heated long path cell (LPC). Methane, toluene, benzene, chlorobenzene, hydrogen chloride and carbon monoxide in the flue gas were simultaneously analyzed. Experimental results indicate that benzene is a major product of incomplete combustion (PIC), besides carbon monoxide, in the incineration of toluene and chlorobenzene and is very sensitive to the combustion conditions. This suggests that benzene is a target analyte to be monitored in full-scale incinerators.

  8. Performance test plan for a space station toluene heater tube

    SciTech Connect

    Parekh, M.B.

    1987-10-01

    Sundstrand Energy Systems was awarded a contract to investigate the performance capabilities of a toluene heater tube integral to a heat pipe as applied to the Organic Rankine Cycle (ORC) solar dynamic power system for the Space Station. This heat pipe is a subassembly of the heat receiver. The heat receiver, the heat absorption component of the ORC solar dynamic power system, consists of forty liquid metal heat pipes located circumferentially around the heat receiver`s outside diameter. Each heat pipe contains a toluene heater, two thermal energy storage (TES) canisters and potassium. The function of the heater tube is to heat the supercritical toluene to the required turbine inlet temperature. During the orbit of the space station, the heat receiver and thereby the heat pipe and heater tube will be subjected to variable heat input. The design of the heater must be such that it can accommodate the thermal and hydraulic variations that will be imposed upon it.

  9. SYNCHROTRON X-RAY MICROTOMOGRAPHY, ELECTRON PROBE MICROANALYSIS, AND NMR OF TOLUENE WASTE IN CEMENT.

    SciTech Connect

    BUTLER,L.G.

    1999-07-22

    Synchrotron X-ray microtomography shows vesicular structures for toluene/cement mixtures, prepared with 1.22 to 3.58 wt% toluene. Three-dimensional imaging of the cured samples shows spherical vesicles, with diameters ranging from 20 to 250 {micro}m; a search with EPMA for vesicles in the range of 1-20 {micro}m proved negative. However, the total vesicle volume, as computed from the microtomography images, accounts for less than 10% of initial toluene. Since the cements were cured in sealed bottles, the larger portion of toluene must be dispersed within the cement matrix. Evidence for toluene in the cement matrix comes from {sup 29}Si MAS NMR spectroscopy, which shows a reduction in chain silicates with added toluene. Also, {sup 2}H NMR of d{sub 8}-toluene/cement samples shows high mobility for all, toluene and thus no toluene/cement binding. A model that accounts for all observations follows: For loadings below about 3 wt%, most toluene is dispersed in the cement matrix, with a small fraction of the initial toluene phase separating from the cement paste and forming vesicular structures that are preserved in the cured cement. Furthermore, at loadings above 3 wt%, the abundance of vesicles formed during toluene/cement paste mixing leads to macroscopic phase separation (most toluene floats to the surface of the cement paste).

  10. DEGRADATION OF TRICHLOROETHYLENE UNDER HIGH-TEMPERATURE THERMAL SOURCE-ZONE REMOVAL CONDITIONS (ABSTRACT ONLY)

    EPA Science Inventory

    Trichloroethylene (TCE) is a contaminant commonly found in the subsurface at industrial and military installations in the United States. Oxidation of TCE (C2HCl3) to carbon dioxide (CO2) and chloride ions (Cl-) has been reported to occu...

  11. EFFECTS OF TRICHLOROETHYLENE AND ITS METABOLITES ON RODENT HEPATOCYTE INTERCELLULAR COMMUNICATION

    EPA Science Inventory

    Chronic exposure to trichloroethylene (TCE) results in hepatocellular cancer in mice but not rats. The induction of hepatic tumors by TCE appears to be mediated through nongenotoxic or tumor promotion mechanisms. One cellular effect exhibited by a number of nongentoxic carcinogen...

  12. Long-Term Capacity of Plant Mulch to Remediate Trichloroethylene in Groundwater

    EPA Science Inventory

    Passive reactive barriers are commonly used to treat groundwater that is contaminated with chlorinated solvents such as trichloroethylene (TCE). A number of passive reactive barriers have been constructed with plant mulch as the reactive medium. The TCE is removed in these barr...

  13. CATALYTIC STEAM REFORMING OF CHLOROCARBONS: TRICHLOROETHANE, TRICHLOROETHYLENE AND PERCHLOROETHYLENE. (R826694C633)

    EPA Science Inventory

    The effective destruction of trichloroethane, trichloroethylene and perchloroethylene by steam reforming with a commercial nickel catalyst has been demonstrated. Conversion levels of up to 0.99999 were attained in both laboratory and semi-pilot experiments, with the products c...

  14. TRICHLOROETHYLENE SORPTION AND OXIDATION USING A DUAL FUNCTION SORBENT/CATALYST IN A FALLING FURNACE REACTOR

    EPA Science Inventory

    A dual function medium (Cr-ZSM-5), capable of physisorbing trichloroethylene (TCE) at ambient temperature and catalytically oxidizing it at elevated temperature (-350 degrees C) was utilized in a novel continuous falling furnace reactor system to store and periodically destroy t...

  15. EFFECTS OF TEMPERATURE ON TRICHLOROETHYLENE DESORPTION FROM SILICA GEL AND NATURAL SEDIMENTS. 2. KINETICS. (R822626)

    EPA Science Inventory

    Isothermal desorption rates were measured at 15, 30, and 60 src="/ncer/pubs/images/deg.gif">C for trichloroethylene (TCE) on a silica gel,
    an aquifer sediment, a soil, a sand fraction, and a clay and silt fraction, all
    at 100% relative humidity. Temperature-st...

  16. HARMONIZATION AND COMMUNICATION OF PBPK MODELS USING THE EXPOSURE RELATED DOSE ESTIMATION MODEL (ERDEM) SYSTEM: TRICHLOROETHYLENE

    EPA Science Inventory

    In support of the trichloroethylene (TCE) risk assessment for the Office of Air and Radiation, Office of Solid Waste and Emergency Response, and Office of Water, NERL and NCEA are developing an updated physiologically-based pharmacokinetic (PBPK) model. The PBPK modeling effort ...

  17. HARMONIZATION AND COMMUNICATION OF PBPK MODELS USING THE EXPOSURE RELATED DOSE MODEL (ERDEM) SYSTEM: TRICHLOROETHYLENE

    EPA Science Inventory

    In support of the trichloroethylene (TCE) risk assessment for the Office of Air and Radiation, Office of Solid Waste and Emergency Response, and Office of Water, NERL and NCEA are developing an updated physiologically-based pharmacokinetic (PBPK) model. The PBPK modeling effor...

  18. The Implication of Iron Oxide Nanoparticles on the Removal of Trichloroethylene by Adsorption

    EPA Science Inventory

    The fate and transport of Fe2O3 NPs in a granular activated carbon (GAC) adsorber and its impact on the removal of trichloroethylene (TCE) by GAC was investigated. The hydrodynamic diameter of Fe2O3 NPs was measured with time to evaluat...

  19. A SEARCH FOR RESIDUAL BEHAVIORAL EFFECTS OF TRICHLOROETHYLENE (TCE) IN RATS EXPOSED AS YOUNG ADULTS

    EPA Science Inventory

    Trichloroethylene (TCE) is a solvent of concern to the EPA due to its extensive use in industry, its prevalence in urban air, and its appearance in water supplies. Human clinical studies have associated short and long-termsolvent exposures with cognitive dysfunction including att...

  20. Development of a replacement for trichloroethylene in the two-stage cleaning process

    SciTech Connect

    Harding, W.B.

    1992-12-01

    A solvent was sought to replace trichloroethylene in the two-stage cleaning process that is used in the Allied-Signal Inc., Kansas City Division (KCD) Miniature Electro-Mechanical Assembly Department. The process is an ultrasonic cleaning process in which product is first cleaned in trichloroethylene and then in isopropyl alcohol. After a general review of the properties of available solvents, isopropyl alcohol, d-limonene, and a synthetic mineral spirits, were chosen to be evaluated as trichloroethylene replacements. Stainless steel test panels were cleaned and then soiled with several different organic materials. Certain of the panels were cleaned by the two-stage process. The others were cleaned by the two-stage process using one or another of the solvents under evaluation in the place of the trichloroethylene. The cleanliness of the panels was determined by Auger and photoelectron spectroscopy. The panels cleaned with any of the three solvents under evaluation were found to be as clean as those cleaned by the standard two-stage process. Because of simplicity and minimization of inventory, it is recommended that the two-stage process be changed to use isopropyl alcohol in both stages.

  1. EFFECTS OF TEMPERATURE ON TRICHLOROETHYLENE DESORPTION FROM SILICA GEL AND NATURAL SEDIMENTS. 1. ISOTHERMS. (R822626)

    EPA Science Inventory

    Aqueous phase isotherms were calculated from vapor phase desorption isotherms
    measured at 15, 30, and 60 C for
    trichloroethylene on a silica gel, an aquifer sediment, a soil, a sand fraction,
    and a clay and silt fraction, all at...

  2. HUMAN ALPHA-7 NICOTINIC ACETYLCHOLINE RECEPTORS EXPRESSED IN XENOPUS OOCYTES ARE INHIBITED BY TRICHLOROETHYLENE.

    EPA Science Inventory

    Trichloroethylene (TCE) is a volatile organic solvent (VOC) that is used as a metal degreasing agent and in paints and glue. In addition to being a commonly abused inhalant, run-off from hazardous waste sites contain enough TCE and other VOCs to contaminate ground water and near...

  3. 78 FR 67372 - Evaluation of Trichloroethylene for the Report on Carcinogens; Request for Nominations of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-12

    ... ). Several comprehensive reviews have identified non-Hodgkin's lymphoma and cancer of the liver and kidney as... trichloroethylene (TCE) and cancer. DATES: The deadline for receipt of nominations of speakers is December 9, 2013... human epidemiologic studies of exposure to TCE and cancer risk and use this input to help inform...

  4. DEGRADATION OF TRICHLOROETHYLENE UNDER HIGH-TEMPERATURE THERMAL SOURCE-ZONE REMOVAL CONDITIONS (POSTER PRESENTATION)

    EPA Science Inventory

    Trichloroethylene (TCE) is a contaminant commonly found in the subsurface at industrial and military installations in the United States. Oxidation of TCE (C2HCl3) to carbon dioxide (CO2) and chloride ions (Cl-) has been reported to occu...

  5. COMPARISON OF MINERAL AND SOLUBLE IRON FENTON'S CATALYSTS FOR THE TREATMENT OF TRICHLOROETHYLENE. (R826163)

    EPA Science Inventory

    Abstract

    Contaminant degradation, stoichiometry, and role of hydroxyl radicals (OH·) in four Fenton's systems were investigated using trichloroethylene (TCE) as a model contaminant. A standard Fenton's system, a modified soluble iron system with a...

  6. TRICHLOROETHYLENE ADSORPTION BY ACTIVATED CARBON PRELOADED WITH HUMIC SUBSTANCES: EFFECTS OF SOLUTION CHEMISTRY. (R828157)

    EPA Science Inventory

    Abstract

    Trichloroethylene (TCE) adsorption by activated carbon previously loaded ("preloaded") with humic substances was found to decrease with increasing concentrations of monovalent ions (NaCl), calcium (until solubility was exceeded), or dissolved oxygen in...

  7. FY00 Phytoremediation of Trichloroethylene and Perchloroethylene in the Southern Sector of SRS

    SciTech Connect

    Brigmon, R.L.

    2000-12-15

    This treatability study addresses the fate of volatile organic contaminants (VOCs) in an experiment that simulates a vegetated seepline supplied with trichloroethylene (TCE) and perchloroethylene (PCE) -contaminated groundwater. The primary objective is to determine how the trees uptake TCE and PCE, accumulate it, and/or transform it.

  8. EFFECTS OF PH ON DECHLORINATION OF TRICHLOROETHYLENE BY ZERO-VALENT IRON

    EPA Science Inventory

    The reduction rates of trichloroethylene (TCE) using zero-valent iron (ZVI) and the rates of iron hydrolysis were characterized at pH values of 5 to 10. The reduction of TCE by ZVI was carried out in batch reactors filled with pH-buffered (phosphate based) solutions under anaerob...

  9. INHIBITION OF HUMAN A7 NEURONAL NICOTINIC ACETYLCHOLINE RECEPTORS BY THE VOLATILE ORGANIC SOLVENT TRICHLOROETHYLENE.

    EPA Science Inventory

    Volatile organic compounds such as toleune, trichloroethylene and perchloroethylene are potent and reversible blockers of voltage-gated calcium current in nerve growth factor (NGF)-differentiated pheochromocytoma (PC12) cells. It is hypothesized that effects of VOCs on ICa contri...

  10. SPERMATID MICRONUCLEUS ANALYSES OF TRICHLOROETHYLENE AND CHLORAL HYDRATE EFFECTS IN MICE

    EPA Science Inventory

    Mice were exposed by inhalation to trichloroethylene (TCE), or by i.p. injection to the TCE metabolite, chloral hydrate (CH). arly spermatids were analyzed for micronucleus (MN) frequency and kinetochore status (presence or absence) using fluorochrome-labeled anti-kinetochore ant...

  11. MICROBIAL DEGRADATION OF TOLUENE UNDER SULFATE- REDUCING CONDITIONS AND THE INFLUENCE OF IRON ON THE PROCESS

    EPA Science Inventory

    Toluene degradation occurred concomitantly with sulfate reduction in anaerobic microcosms inoculated with contaminated subsurface soil from an aviation fuel storage facility near the Patuxent River (Md.). Similar results were obtained for enrichment cultures in which toluene was ...

  12. FORMATION OF POLYKETONES IN IRRADIATED TOLUENE/PROPYLENE/NOX/AIR MIXTURES

    EPA Science Inventory

    A laboratory study was carried out to investigate the formation of polyketones in secondary organic aerosol from photooxidation of the aromatic hydrocarbon toluene, a major constituent of automobile exhaust. The laboratory experiments consisted of irradiating toluene/propylene...

  13. PERINATAL STUDY OF TOLUENE IN CD-1 MICE

    EPA Science Inventory

    Toluene administered by inhalation at 400 ppm to CD-1 mice from Days 6 to 16 of gestation was teratogenic but not fetotoxic resulting in a significant shift in the fetal rib profile. At the lower concentration of 200 ppm, there was an increase in dilated renal pelves which might ...

  14. 2,4-/2,6-Toluene diisocyanate mixture (TDI)

    Integrated Risk Information System (IRIS)

    2,4 - / 2,6 - Toluene diisocyanate mixture ( TDI ) ; CASRN 26471 - 62 - 5 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Haz

  15. Fenton-like initiation of a toluene transformation mechanism

    EPA Science Inventory

    In Fenton-driven oxidation treatment systems, reaction intermediates derived from parent compounds can play a significant role in the overall treatment process. Fenton-like reactions in the presence of toluene or benzene, involved a transformation mechanism that was highly effici...

  16. TOLUENE DOSE-EFFECT META ANALYSIS AND IMPORTANCE OF EFFECTS

    EPA Science Inventory

    TOLUENE DOSE-EFFECT META ANALYSES AND IMPORTANCE OF EFFECTS
    Benignus, V.A., Research Psychologist, ORD, NHEERL, Human Studies Division,
    919-966-6242, benignus.vernon@epa.gov
    Boyes, W.K., Supervisory Health Scientist, ORD, NHEERL, Neurotoxicology Division
    919-541-...

  17. HYPERTENSIVE AND TACHYCARDIC RESPONSES TO ORAL TOLUENE IN THE RAT.

    EPA Science Inventory

    Little is known regarding the effects of toluene and other volatile organic compounds on autonomic processes. Such studies should be performed in unrestrained and undisturbed animals to avoid the effects of handling stress on processes regulated by the autonomic nervous system. T...

  18. PHOSPHOLIPIDS OF FIVE PSEUDOMONAD ARCHETYPES FOR DIFFERENT TOLUENE DEGRADATION PATHWAYS

    EPA Science Inventory

    Liquid chromatography/electrospray ionization/mass spectrometry (LC/ESI/MS) was used to determine phospholipid profiles for five reference pseudomonad strains harboring distinct toluene catabolic pathways: Pseudomonas putida mt-2, Pseudomonas putida F1, Burkholderia cepacia G4, B...

  19. Mass accommodation of aniline, phenol and toluene on aqueous droplets

    SciTech Connect

    Heal, M.R.; Pilling, M.J.; Titcombe, P.E.

    1995-11-15

    This report describes measurements of mass accommodation coefficients at a temperature of 283k for the volatile organic compounds aniline, phenol, and toluene using the droplet train method. Laser induced fluoresecence was used as a detection method for the trace molecules.

  20. Trichloroethylene effects on gene expression during cardiac development

    SciTech Connect

    Collier, John Michael; Selmin, Ornella; Johnson, Paula D.; Runyan, Raymond B.

    2003-05-09

    Background: Halogenated hydrocarbon exposure is associated with changes in gene expression in adult and embryonic tissue. The present study was undertaken to identify differentially expressed mRNA transcripts in embryonic hearts from Sprague-Dawley rats exposed to trichloroethylene (TCE) or potential bio-transformation products of TCE, Dichloroethylene (DCE) and Trichloroacetic acid (TCAA). Methods: cDNA subtractive hybridization was used to selectively amplify expressed mRNA in either control or day 11 embryonic rat hearts exposed to one of these halogenated hydrocarbons from day 0 to 11. The doses used were 1100 and 110 ppm (8300 and 830 mu M) TCE, 110 and 11 ppm (1100 and 110 mu M) DCE, 27.3 and 2.75 mg/ml (100 and 10 mM) TCAA. Control animals were given distilled drinking water throughout the period of experiments. Results: Sequencing of over 100 clones derived from halogenated hydrocarbon exposed groups=resulted in identification of numerous differentially regulate gene sequences. Up-regulated transcripts identified include genes associated with stress response (Hsp 70) and homeostasis (several ribosomal proteins). Down-regulated transcripts include extracellular matrix components (GPI-p137 and vimentin) and Ca2 + responsive proteins (Serca-2 Ca2+-ATPase and beta-catenin). Two possible markers for fetal TCE exposure were identified: Serca-2 and GPI-p137, a GPI-linked protein of unknown function. Both markers show a dose-related decrease in mRNA transcript levels associated with fetal exposure to TCE. Differential regulation of expression of both markers by TCE was confirmed by dot blot analysis and semi-quantitative RT-PCR. Levels of exposure between 100 and 250 ppb (0.76 and 1.9 mu M) TCE are sufficient to decrease expression of both the Ca2+-AT Pase and GPI-p137. Conclusion: Sequences down-regulated with TCE exposure appear to be those associated with cellular=housekeeping, cell adhesion and developmental processes, while TCE=exposure up-regulates expression

  1. Dioxinlike properties of a trichloroethylene combustion-generated aerosol.

    PubMed Central

    Villalobos, S A; Anderson, M J; Denison, M S; Hinton, D E; Tullis, K; Kennedy, I M; Jones, A D; Chang, D P; Yang, G; Kelly, P

    1996-01-01

    Conventional chemical analyses of incineration by-products identify compounds of known toxicity but often fail to indicate the presence of other chemicals that may pose health risks. In a previous report, extracts from soot aerosols formed during incomplete combustion of trichloroethylene (TCE) and pyrolysis of plastics exhibited a dioxinlike response when subjected to a keratinocyte assay. To verify this dioxinlike effect, the complete extract, its polar and nonpolar fractions, some containing primarily halogenated aromatic hydrocarbons, were evaluated for toxicity using an embryo assay, for antiestrogenicity using primary liver cell cultures, and for the ability to transform the aryl hydrocarbon receptor into its DNA binding form using liver cytosol in a gel retardation assay. Each of these assays detect dioxinlike effects. Medaka (Oryzias latipes) embryos and primary liver cell cultures of rainbow trout (Oncorhynchus mykiss) were exposed to concentrations of extract ranging from 0.05 to 45 micrograms/l. Cardiotoxicity with pericardial, yolk sac, and adjacent peritoneal edema occurred after exposure of embryos to concentrations of 7 micrograms/l or greater. These same exposure levels were associated with abnormal embryo development and, at the higher concentrations, death. Some of the fractions were toxic but none was as toxic as the whole extract. In liver cells, total cellular protein and cellular lactate dehydrogenase activity were not altered by in vitro exposure to whole extract (0.05-25 micrograms/l). However, induction of cytochrome P4501A1 protein and ethoxyresorufin O-deethylase activity occurred. In the presence of whole extract, estradiol-dependent vitellogenin synthesis was reduced. Of the fractions, only fraction 1 (nonpolar) showed a similar trend, although vitellogenin synthesis inhibition was not significant. The soot extract and fractions bound to the Ah receptor and showed a significantly positive result in the gel retardation/DNA binding test

  2. Final amended report of the safety assessment of toluene-2,5-diamine, toluene-2,5-diamine sulfate, and toluene-3,4-diamine as used in cosmetics.

    PubMed

    Burnett, Christina L; Bergfeld, Wilma F; Belsito, Donald V; Klaassen, Curtis D; Marks, James G; Shank, Ronald C; Slaga, Thomas J; Snyder, Paul W; Alan Andersen, F

    2010-05-01

    Toluene-2,5-diamine, toluene-2,5-diamine sulfate, and toluene-3,4-diamine are diaminotoluenes used as colorants in permanent hair dyes and tints. Toluene-2,5-diamine is used in 79 products at concentrations up to 3%; toluene-2,5-diamine sulfate is used in 168 products at concentrations up to 4%. Toluene-3,4-diamine does not appear to be in current use. Previously, the Cosmetic Ingredient Review Expert Panel determined that all 3 ingredients were safe for use as hair dyes. New data suggest that differences in toxicity, especially with respect to carcinogenicity, may exist as a function of placement of amine groups around the benzene ring. The Expert Panel concluded that toluene-2,5-diamine and toluene-2,5-diamine sulfate and are safe as hair dye ingredients in the present practices of use and concentrations but that there are insufficient data supporting the safety of toluene-3,4-diamine. PMID:20448268

  3. Audition and exhibition to toluene - a contribution for the theme

    PubMed Central

    Augusto, Lívia Sanches Calvi; Kulay, Luiz Alexandre; Franco, Eloisa Sartori

    2012-01-01

    Summary Introduction: With the technological advances and the changes in the productive processes, the workers are displayed the different physical and chemical agents in its labor environment. The toluene is solvent an organic gift in glues, inks, oils, amongst others. Objective: To compare solvent the literary findings that evidence that diligent displayed simultaneously the noise and they have greater probability to develop an auditory loss of peripheral origin. Method: Revision of literature regarding the occupational auditory loss in displayed workers the noise and toluene. Results: The isolated exposition to the toluene also can unchain an alteration of the auditory thresholds. These audiometric findings, for ototoxicity the exposition to the toluene, present similar audiograms to the one for exposition to the noise, what it becomes difficult to differentiate a audiometric result of agreed exposition - noise and toluene - and exposition only to the noise. Conclusion: The majority of the studies was projected to generate hypotheses and would have to be considered as preliminary steps of an additional research. Until today the agents in the environment of work and its effect they have been studied in isolated way and the limits of tolerance of these, do not consider the agreed expositions. Considering that the workers are displayed the multiples agent and that the auditory loss is irreversible, the implemented tests must be more complete and all the workers must be part of the program of auditory prevention exactly displayed the low doses of the recommended limit of exposition. PMID:25991943

  4. Cardiovascular effects of oral toluene exposure in the rat monitored by radiotelemetry

    EPA Science Inventory

    Toluene is a hazardous air pollutant that can be toxic to the nervous and cardiovascular systems. The cardiotoxicity data for toluene come from acute studies in anesthetized animals and from clinical observations made on toluene abusers and there is little known on the response o...

  5. 40 CFR 721.10610 - Toluene diisocyanate, polymers with polyalkylene glycol (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Toluene diisocyanate, polymers with... New Uses for Specific Chemical Substances § 721.10610 Toluene diisocyanate, polymers with polyalkylene... substances identified generically as toluene diisocyanate, polymers with polyalkylene glycol (PMNs...

  6. 40 CFR 721.10610 - Toluene diisocyanate, polymers with polyalkylene glycol (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Toluene diisocyanate, polymers with... New Uses for Specific Chemical Substances § 721.10610 Toluene diisocyanate, polymers with polyalkylene... substances identified generically as toluene diisocyanate, polymers with polyalkylene glycol (PMNs...

  7. 75 FR 52768 - Withdrawal of Approval of New Animal Drug Applications; Dichlorophene and Toluene Capsules

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-27

    ...; Dichlorophene and Toluene Capsules AGENCY: Food and Drug Administration, HHS. ACTION: Notice. SUMMARY: The Food... use of dichlorophene and toluene deworming capsules for cats and dogs. In a final rule published... withdraw approval of NADA 101-497 for TINY TIGER (dichlorophene/toluene) Worming Capsules, NADA 101-498...

  8. INFLUENCES OF PH AND CURRENT ON ELECTROLYTIC DECHLORINATION OF TRICHLOROETHYLENE AT A GRANULAR-GRAPHITE PACKED ELECTRODE

    EPA Science Inventory

    Electrolytic dechlorination using a granular-graphite packed cathode is an alternative method for the remediation of chlorinated organic compounds. Its effectiveness under various conditions needs experimental investigation. Dechlorination of trichloroethylene (TCE) was conducted...

  9. AN EXAMPLE OF MODEL STRUCTURE DIFFERENCES USING SENSITIVITY ANALYSES IN PHYSIOLOGICALLY BASED PHARMACOKINETIC MODELS OF TRICHLOROETHYLENE IN HUMANS

    EPA Science Inventory

    Abstract Trichloroethylene (TCE) is an industrial chemical and an environmental contaminant. TCE and its metabolites may be carcinogenic and affect human health. Physiologically based pharmacokinetic (PBPK) models that differ in compartmentalization are developed for TCE metabo...

  10. Performances of toluene removal by activated carbon derived from durian shell.

    PubMed

    Tham, Y J; Latif, Puziah Abdul; Abdullah, A M; Shamala-Devi, A; Taufiq-Yap, Y H

    2011-01-01

    In the effort to find alternative low cost adsorbent for volatile organic vapors has prompted this research in assessing the effectiveness of activated carbon produced from durian shell in removing toluene vapors. Durian shells were impregnated with different concentrations of H3PO4 followed by carbonization at 500 °C for 20 min under nitrogen atmosphere. The prepared durian shell activated carbon (DSAC) was characterized for its physical and chemical properties. The removal efficiency of toluene by DSAC was performed using different toluene concentrations. Results showed that the highest BET surface area of the produced DSAC was 1404 m2/g. Highest removal efficiency of toluene vapors was achieved by using DSAC impregnated with 30% of acid concentration heated at 500 °C for 20 min heating duration. However, there is insignificant difference between removal efficiency of toluene by DSAC and different toluene concentrations. The toluene adsorption by DSAC was better fitted into Freundlich model. PMID:20884200

  11. Evidence that anaerobic oxidation of toluene in the denitrifying bacterium Thauera aromatica is initiated by formation of benzylsuccinate from toluene and fumarate.

    PubMed

    Biegert, T; Fuchs, G; Heider, J

    1996-06-15

    Toluene is degraded anoxically to CO2 by the denitrifying bacterium Thauera aromatica. Toluene first becomes oxidized to benzoyl-CoA by O2-independent reactions. Benzoyl-CoA is then reduced to non-aromatic products by benzoyl-CoA reductase. We set out to study the reactions employed for the initial activation of toluene and its oxidation to the level of benzoate. Evidence is provided for a novel way of toluene degradation based on experiments with cell-free extracts and with whole toluene-grown cells: Cell-free extracts oxidized [14C]toluene to [14C]benzoyl-CoA via several radioactive intermediates. This reaction was strictly dependent on the presence of fumarate, coenzyme A and nitrate as electron acceptor; acetyl-CoA and ATP were not necessary for the reaction. The first product formed in vitro was benzylsuccinate; (2H8)toluene was converted to (2H7)benzylsuccinate. Formation of benzylsuccinate from toluene was independent of coenzyme A and nitrate, but it required the presence of fumarate. Other tricarboxylic acid cycle intermediates were converted to fumarate in cell extracts and therefore could partially substitute for fumarate. [14C]Benzylsuccinate was oxidized further to [14C]benzoyl-CoA and [14C]benzoate in cell extracts if coenzyme A and nitrate were present. No benzyl alcohol and benzaldehyde and no phenylpropionate could be detected as intermediates. In isotope trapping experiments with cell suspensions, two intermediates from [14C]toluene were detected, benzoate and benzylsuccinate. This corroborates the sequence of reactions deduced from in vitro experiments. A hypothetical degradation pathway for the anaerobic oxidation of toluene to benzoyl-CoA via an initial addition of fumarate to the methyl group of toluene and following beta-oxidation of the benzylsuccinate formed is suggested. PMID:8706665

  12. Chemical Sensing with a Magnetically-Excitied Flexural Plate Wave Resonator

    SciTech Connect

    Adkins, D.R.; Butler, M.A.; Kottenstette, R.; Martin, S.J.; Mitchell, M.A.; Schubert, W.K.; Wessendorf, K.O.

    1999-05-26

    Chemical sensing with a magnetically excited flexural plate wave (mag- FPW) resonator has been demonstrated for the first time. One surface of the resonator was coated with ethyl cellulose to impart sensitivity to volatile solvents such as chloroform, tetrachloroethylene, trichloroethylene, and toluene. The absorbed mass of the analyte causes a shift in the membrane resonance frequency of the two-port mag-FPW resonator. An oscillator circuit is used to track the resonance frequency, providing a convenient means of monitoring analyte concentration levels. Analyte concentrations of 10 ppm were easily detected.

  13. Photocatalytic degradation of toluene by platinized titanium dioxide photocatalysts.

    PubMed

    Young, C; Lim, T M; Chiang, K; Amal, R

    2004-01-01

    A photoreactor has been set up to study the photodegradation of volatile organic compound (VOC) in situ. In the reactor, TiO2 and Pt/TiO2 photocatalysts were immobilized on to UV-transparent quartz support. Scanning electron microscope (SEM) studies and Brunauer-Emmett-Teller (BET) surface area measurements revealed that the quartz fiber support was mostly coated with catalyst with a total surface area of 4.0 +/- 0.3 m2/g. The photocatalytic activity of the photocatalysts was evaluated for the photodegradation of 160 ppm toluene-laden air. It was found that 50-70% of toluene was degraded within the first 5 min of UV illumination. Both TiO2 and Pt/TiO2 photocatalysts suffered from deactivation after 18 hours of continuous operation, and the photocatalysts' activity was significantly reduced. However, platinization doubled the photocatalyst life and delayed the onset of de-activation. The presence of moisture was found to shift the onset of catalyst de-activation to an earlier time. It is concluded that the de-activation of the photocatalyst was due to the accumulation of intermediates on the photocatalysts surface preventing the toluene being adsorbed on the photocatalyst surface for degradation. PMID:15484768

  14. Formation of Formaldehyde and Glyoxal From The Toluene + Oh Reaction

    NASA Astrophysics Data System (ADS)

    Volkamer, R.; Wirtz, K.; Platt, U.

    Aromatic hydrocarbons are emitted into the urban atmosphere mostly as part of au- tomobile exhaust. Toluene thereby is the single most abundant aromatic compound emitted into the atmosphere. Despite the importance of aromatic hydrocarbon oxi- dation for the formation of photooxidants from urban plumes the oxidation mech- anism of aromatic hydrocarbons is far from being understood.Considerable progress has been made in recent years concerning our understanding of the ring-retaining path- ways, while major uncertainties remain to be linked with the operative ring-cleavage mechanisms. The representation of the aromatic oxidation in presently used chemical transport models (CTM) is estimated a major uncertainty for these models. This work presents data on formaldehyde (HCHO) and glyoxal, which are two impor- tant ring-cleavage products from the the toluene + OH reaction. While glyoxal was observed to form as a high yield primary product (Volkamer et al., JPC A, 2001, 105, 7865-7874) the formation of HCHO is observed delayed, i.e. as a secondary prod- uct. The temporal behaviour of glyoxal and HCHO concentrations allowed to con- clude that short lived stable intermediate compounds must form upon ring-cleavage of toluene. With an approximate lifetime of the order of ten minutes, these highly reac- tive intermediate compounds are likely to be a significant radical source. Atmospheric implications of the results are adressed.

  15. Microbial degradation of benzene and toluene in groundwater

    SciTech Connect

    Karlson, U.; Frankenberger, W.T. Jr. )

    1989-10-01

    Certain organic pollutants reaching the groundwater are subject to biotransformations. Currently, remedial measures promoting microbial degradation of pollutants are becoming very attractive because of their cost-effectiveness in removal of the contaminants. Current technology for reclaiming groundwater polluted with petroleum hydrocarbons involves (i) pumping the water into an aerated stripping tower, (ii) removal by sorbents, or (iii) biodegradation in situ or pumped into a bioreactor. Among the bioreactors, fixed film and suspended growth reactors are the most popular systems. Gasoline contamination of groundwaters is becoming an alarming and widespread problem. A major concern with petroleum contamination is the benzene, toluene and xylene (BTX) content reaching the groundwater because of their solubility and high toxicity. The state of California Department of Health Services now recommends that remedial action be taken when the concentration of benzene and toluene exceeds 0.7 and 100 {mu}g L{sup {minus}1}, respectively. The purpose of this study was to assess biodegradation of benzene and toluene in groundwater upon amendment with nutrients and an enriched hydrocarbon oxidizing culture.

  16. Toluene nitration in irradiated nitric acid and nitrite solution

    SciTech Connect

    Gracy Elias; Bruce J. Mincher; Stephen P. Mezyk; Jim Muller; Leigh R. Martin

    2011-04-01

    The kinetics, mechanisms, and stable products produced for the aryl alkyl mild ortho-para director - toluene, in irradiated nitric acid and neutral nitrite solutions were investigated using ?, and pulse radiolysis. Electron pulse radiolysis was used to determine the bimolecular rate constants for the reaction of toluene with different transient species produced by irradiation. HPLC with UV detection was primarily used to assess the stable reaction products. GC-MS and LC-MS were used to confirm the results from HPLC. Free-radical nitration reaction products were found in irradiated acidic and neutral media. In acidic medium, the ring substitution and side chain substitution and oxidation produced different nitro products. In ring substitution, nitrogen oxide radicals were added mainly to hydroxyl radical-produced cyclohexadienyl radical, and in side chain substitution they were added to the carbon-centered benzyl radical produced by H-atom abstraction. In neutral nitrite toluene solution, radiolytic ring nitration products approached a statistically random distribution, suggesting a free-radical reaction involving addition of the •NO2 radical.

  17. Photolysis Kinetics of Toluene, Ethylbenzene, and Xylenes at Ice Surfaces.

    PubMed

    Stathis, Alexa A; Hendrickson-Stives, Albanie K; Kahan, Tara F

    2016-09-01

    Benzene, toluene, ethylbenzene, and xylenes (BTEX) are important organic pollutants. These compounds do not undergo direct photolysis in natural waters because their absorbance spectra do not overlap with solar radiation at the Earth's surface. Recent research has suggested that benzene is able to undergo direct photolysis when present at ice surfaces. However, the photolysis of toluene, ethylbenzene, and xylenes (TEX) at ice surfaces has not been investigated. Using fluorescence spectroscopy, photolysis rate constants were measured for TEX in water, in ice cubes, and in ice granules which reflect reactivity at ice surfaces. No photolysis was observed in water or ice cubes. Photolysis was observed in ice granules; rate constants were (4.5 ± 0.5) × 10(-4) s(-1) (toluene), (5.4 ± 0.3) × 10(-4) s(-1) (ethylbenzene), and (3.8 ± 1.2) × 10(-4) s(-1) (xylenes). Photolysis of TEX molecules appears to be enabled by a red shift in the absorbance spectra at ice surfaces, although photosensitization may also occur. The results suggest that direct photolysis could be an important removal pathway for TEX in snow-covered environments. PMID:27513159

  18. Atmospheric pressure discharge plasma decomposition for gaseous air contaminants -- Trichlorotrifluoroethane and trichloroethylene

    SciTech Connect

    Oda, Tetsuji; Yamashita, Ryuichi; Takahashi, Tadashi; Masuda, Senichi

    1996-03-01

    The decomposition performance of gaseous environmental destructive contaminants in air by using atmospheric pressure discharged plasma including the surface discharge induced plasma chemical processing (SPCP) was examined. The main contaminants tested were chlorofluorocarbon (CFC-113) and trichloroethylene, typically. The discharge exciting frequency range studied was wide--50 Hz to 50 kHz. Results showed the low frequency discharge requires high voltage to inject high electric power in the gas and to decompose the contaminants. A Gas Chromatograph Mass Spectrometer was used to analyze discharge products of dense CFC-113 or trichloroethylene. Among the detected products were HCl, CClFO, and CHCl{sub 3}. Two different electrode configurations; the silent discharge (coaxial) electrode and the coil-electrode were also tested and compared to each other as a gas reactor.

  19. [Psychopathometrical results of follow-up studies of trichloroethylene-exposed persons (author's transl)].

    PubMed

    Triebig, G; Lehrl, S; Kinzel, W; Erzigkeit, H; Galster, J V; Schaller, K H

    1977-01-01

    Seven clinical healthy volunteers were exposed to trichloroethylene concentration in air with 520 mg/m3 (100 ppm) at an average 6 hours a day on 5 consecutive days. Corresponding volunteers were exposed to a placebo for the same period. --The persons were examined psychopathometrically and biochemically at the beginning and after every day of exposure. The trichloroethylene-metabolites in blood and urine were dated in order to quantify the loads. --Purpose of the psychopathometrical testing methods was the observation, whether a psychological impairment in the sense of a "psychoorganic syndrome" may occur under these exposition-conditions. --Standardized achievement-tests and self-report rating scales were used in order to demonstrate reversible physical provable psychosis that may be possible. Comparing the psychopathometrical results of the exposed and non-exposed volunteers no statistical significant difference was visible in spite of the analytically proved considerable incorporation of the solvent. PMID:329621

  20. Effect of air sparging on fate and transport of trichloroethylene in chambers with alfalfa plants

    SciTech Connect

    Zhang, Q.; Hu, J.; Erickson, L.E.; Davis, L.C.

    1997-12-31

    To study the effect of air sparging in soil with trichloroethylene present as a dense nonaqueous phase, air was supplied through pipes installed at the bottom of two chambers planted with alfalfa. Air input rate was 2.14 L/m{sup 2}/day. The fate of trichloroethylene (TCE) was investigated by monitoring TCE concentration in both outflow groundwater and soil gas. Comparison of these results with those of the previous study without air sparging indicates that air sparging appreciably increases the groundwater concentration of TCE. The soil gas at the surface shows even greater concentration difference. The flux of TCE to the atmosphere is increased significantly by air input. Accordingly, the authors can conclude that air sparging improved mass transfer of TCE from the nonaqueous phase to groundwater phase. Air sparging appeared to negatively impact the health of the alfalfa because of the elevated TCE present in the vadose zone of the chamber.

  1. Structural Magnetic Resonance Imaging in an adult cohort following prenatal and early postnatal exposure to tetrachloroethylene (PCE)-contaminated drinking water.

    PubMed

    Janulewicz, Patricia A; Killiany, Ronald J; White, Roberta F; Martin, Brett M; Winter, Michael R; Weinberg, Janice M; Aschengrau, Ann

    2013-01-01

    This population-based retrospective cohort study examined Structural Magnetic Resonance Imaging (MRI) of the brain in relation to prenatal and early postnatal exposure to tetrachloroethylene (PCE)-contaminated drinking water on Cape Cod, Massachusetts. Subjects were identified through birth records from 1969 through 1983. Exposure was modeled using pipe network information from town water departments, a PCE leaching and transport algorithm, EPANet water flow modeling software, and Geographic Information System (GIS) methodology. Brain imaging was performed on 26 exposed and 16 unexposed subjects. Scans were acquired on a Philips 3T whole body scanner using the ADNI T1-weighted MP-RAGE scan. The scans were processed by FreeSurfer version 4.3.1 software to obtain measurements of specific brain regions. There were no statistically significant differences between exposed and unexposed subjects on the measures of white matter hypointensities (β: 127.5mm(3), 95% CI: -259.1, 1514.0), white matter volumes (e.g. total cerebral white matter: β: 21230.0mm(3), 95% CI: -4512.6, 46971.7) or gray matter volumes (e.g. total cerebral gray matter: β: 11976.0mm(3), 95% CI: -13657.2, 37609.3). The results of this study suggest that exposure to PCE during gestation and early childhood, at the levels observed in this population, is not associated with alterations in the brain structures studied. PMID:23571160

  2. Structural Magnetic Resonance Imaging in an Adult Cohort Following Prenatal and Early Postnatal Exposure to Tetrachloroethylene (PCE)-contaminated Drinking Water

    PubMed Central

    Janulewicz, Patricia A; Killiany, Ronald J; White, Roberta F; Martin, Brett M; Winter, Michael R; Weinberg, Janice M; Aschengrau, Ann

    2013-01-01

    This population-based retrospective cohort study examined Structural Magnetic Resonance Imaging (MRI) of the brain in relation to prenatal and early postnatal exposure to tetrachloroethylene (PCE)-contaminated drinking water on Cape Cod, Massachusetts. Subjects were identified through birth records from 1969 through 1983. Exposure was modeled using pipe network information from town water departments, a PCE leaching and transport algorithm, EPANet water flow modeling software, and Geographic Information System (GIS) methodology. Brain imaging was performed on 26 exposed and 16 unexposed subjects. Scans were acquired on a Philips 3T whole body scanner using the ADNI T1-weighted MP-RAGE scan. The scans were processed by FreeSurfer version 4.3.1 software to obtain measurements of specific brain regions. There were no statistically significant differences between exposed and unexposed subjects on measures of white matter hypointensities (β: 127.5 mm3, 95% CI: −259.1, 1514.0), white matter volumes (e.g. total cerebral white matter: β: 21230.0 mm3, 95% CI: −4512.6, 46971.7) or gray matter volumes (e.g. total cerebral gray matter: β: 11976.0 mm3, 95% CI: −13657.2, 37609.3). The results of this study suggest that exposure to PCE during gestation and early childhood, at the levels observed in this population, is not associated with alterations in the brain structures studied. PMID:23571160

  3. EFFECTS OF PH ON DECHLORINATION OF TRICHLOROETHYLENE BY ZERO-VALENT IRON

    EPA Science Inventory

    The surface normalized reaction rate constants (ksa) of trichloroethylene (TCE) and zero-valent iron (ZVI) was quantified in batch reactors at pH values between 1.7 and 10. The ksa of TCE linearly decreased from 0.044 to 0.009 L/hr-m2 between pH 3.8 and 8.0, whereas the ksa at pH...

  4. Physical properties of contaminated trichloroethylene and 1,1,1- trichloroethane

    SciTech Connect

    Holt, R.D.

    1990-10-01

    The specific gravity, volume change, dielectric constant, dissipation factor, boiling point, and nonvolatile residue carryover during distillation was measured for various contamination levels of rosin in trichloroethylene and 1,1,1-trichloroethane. Solvent stabilizers and the vapor pressure of solvents were examined. The effects of unknown contamination in solvents from manufacturing departments were measured. The theoretical effects of oil contamination on the boiling point are discussed. 18 refs., 15 figs., 13 tabs.

  5. Acute behavioural comparisons of toluene and ethanol in human subjects.

    PubMed Central

    Echeverria, D; Fine, L; Langolf, G; Schork, T; Sampaio, C

    1991-01-01

    A comparison of toluene and ethanol (EtOH) induced changes in central nervous system (CNS) function and symptoms were evaluated in two studies, and when possible the effects of toluene were expressed in EtOH equivalent units. The toluene concentrations were 0, 75, and 150 ppm, bracketing the American Conference of Governmental Industrial Hygienists threshold limit value (ACGIH TLV) of 100 ppm. The socially relevant EtOH doses were 0.00, 0.33, and 0.66 g EtOH/kg body weight, equivalent to two and four 3.5% 12 ounce beers. Forty two paid college students were used in each study. In the first study, subjects were exposed to toluene and an odour masking agent menthol (0.078 ppm) for seven hours over three days. In the second study EtOH or a placebo was administered at 1530 across three days also in the presence of menthol. Verbal and visual short term memory (Sternberg, digit span, Benton, pattern memory), perception (pattern recognition), psychomotor skill (simple reaction time, continuous performance, symbol-digit, hand-eye coordination, finger tapping, and critical tracking), manual dexterity (one hole), mood (profile on mood scales (POMS), fatigue (fatigue checklist), and verbal ability were evaluated at 0800, 1200, and 1600. Voluntary symptoms and observations of sleep were collected daily. A 3 x 3 latin square design evaluated solvent effects simultaneously controlling for learning and dose sequence. An analysis of variance and test for trend were performed on am-pm differences reflecting an eight hour workday and on pm scores for each solvent, in which subjects were their own control Intersubject variation in absorbance was monitored in breath. A 5 to 10% decrement was considered meaningful if consistent with a linear trend at p less than 0.05. At 150 ppm toluene, losses in performance were 6.0% for digit span, 12.1% for pattern recognition (latency), 5% for pattern memory (number correct), 6.5% for one hole, and 3% for critical tracking. The number of headaches

  6. Determination of toluene in brain of freely moving mice using solid-phase microextraction technique.

    PubMed

    Nakajima, Daisuke; Tin-Tin-Win-Shwe; Kakeyama, Masaki; Fujimaki, Hidekazu; Goto, Sumio

    2006-07-01

    For the purpose of measuring the pharmacokinetics of inhaled toluene in the brain of mice, we developed a method for the direct detection of toluene by gas chromatography/mass spectrometry (GC/MS). The method uses a solid-phase microextraction (SPME) fiber inserted into the mouse' hippocampus (CA1) through a cannula fixed onto the animal. BALB/c mice were exposed to 0, 0.9, 9, 50 and 90 ppm toluene for 30 min. The toluene level detected near the hippocampus by this method after exposure to 0.9 ppm toluene in air showed no significant difference from the level found in the non-exposure control group; however, the toluene level increased significantly after exposure to concentrations of 9, 50 and 90 ppm. These increases were concentration-dependent. In addition, the pharmacokinetics of toluene in the brain of mice exposed to 50 ppm toluene showed that the toluene level decreased rapidly after the exposure, and returned to control levels after 60 min. This study describes the method which has successfully detected toluene levels in the brain of conscious, free-moving mice for the first time. PMID:16457888

  7. Protective effects of quercetine on the neuronal injury in frontal cortex after chronic toluene exposure.

    PubMed

    Kanter, Mehmet

    2013-08-01

    The aim of this study was designed to evaluate the possible protective effects of quercetine (QE) on the neuronal injury in the frontal cortex after chronic toluene exposure in rats. The rats were randomly allotted into one of the three experimental groups, namely, groups A (control), B (toluene treated) and C (toluene-treated with QE), where each group contains 10 animals. Control group received 1 ml of normal saline solution, and toluene treatment was performed by the inhalation of 3000 ppm toluene in an 8-h/day and 6-day/week order for 12 weeks. The rats in QE-treated group was given QE (15 mg/kg body weight) once a day intraperitoneally for 12 weeks, starting just after toluene exposure. Tissue samples were obtained for histopathological investigation. To date, no histopathological changes of neurodegeneration in the frontal cortex after chronic toluene exposure in rats by QE treatment have been reported. In this study, the morphology of neurons in the QE treatment group was well protected. Chronic toluene exposure caused severe degenerative changes, shrunken cytoplasm and extensively dark picnotic nuclei in neurons of the frontal cortex. We conclude that QE therapy causes morphologic improvement in neurodegeneration of frontal cortex after chronic toluene exposure in rats. We believe that further preclinical research into the utility of QE may indicate its usefulness as a potential treatment on neurodegeneration after chronic toluene exposure in rats. PMID:22252859

  8. Toluene induces rapid and reversible rise of hippocampal glutamate and taurine neurotransmitter levels in mice.

    PubMed

    Win-Shwe, Tin-Tin; Mitsushima, D; Nakajima, D; Ahmed, S; Yamamoto, S; Tsukahara, S; Kakeyama, M; Goto, S; Fujimaki, H

    2007-01-10

    Toluene, a widely used aromatic organic solvent, has been well characterized as a neurotoxic chemical. Although the neurobehavioral effects of toluene have been studied substantially, the mechanisms involved are not clearly understood. Hippocampus, which is one of the limbic areas of brain associated with neuronal plasticity, and learning and memory functions, may be a principal target of toluene. In the present study, to establish a mouse model for investigating the effects of acute toluene exposure on the amino acid neurotransmitter levels in the hippocampus, in vivo microdialysis study was performed in freely moving mice after a single intraperitoneal administration of toluene (150 and 300 mg/kg). Amino acid neurotransmitters in microdialysates were measured by a high performance liquid chromatography system. The extracellular levels of glutamate and taurine were rapidly and reversibly increased within 30 min after the toluene administration in a dose-dependent manner and returned to the basal level by 1h. Conversely, the extracellular level of glycine and GABA were stable, and no significant change was observed after the toluene administration. To further investigate the brain toluene level in the hippocampus of toluene-administered mice, we used a solid-phase microextraction (SPME) method and examined the time course changes of toluene in the hippocampus of living mice. The brain toluene level reached the peak at 30 min after injection and returned to the basal level after 2h. In the present study, we observed the relationship between brain toluene levels and amino acid neurotransmitter glutamate and taurine levels in the hippocampus. Therefore, we suggest that toluene may mediate its action through the glutamatergic and taurinergic neurotransmission in the hippocampus of freely moving mice. PMID:17145141

  9. Modeling toxicodynamic effects of trichloroethylene on liver in mouse model of autoimmune hepatitis

    SciTech Connect

    Gilbert, Kathleen M.; Reisfeld, Brad; Zurlinden, Todd J.; Kreps, Meagan N.; Erickson, Stephen W.; Blossom, Sarah J.

    2014-09-15

    Chronic exposure to industrial solvent and water pollutant trichloroethylene (TCE) in female MRL +/+ mice generates disease similar to human autoimmune hepatitis. The current study was initiated to investigate why TCE-induced autoimmunity targeted the liver. Compared to other tissues the liver has an unusually robust capacity for repair and regeneration. This investigation examined both time-dependent and dose-dependent effects of TCE on hepatoprotective and pro-inflammatory events in liver and macrophages from female MRL +/+ mice. After a 12-week exposure to TCE in drinking water a dose-dependent decrease in macrophage production of IL-6 at both the transcriptional and protein level was observed. A longitudinal study similarly showed that TCE inhibited macrophage IL-6 production. In terms of the liver, TCE had little effect on expression of pro-inflammatory genes (Tnfa, Saa2 or Cscl1) until the end of the 40-week exposure. Instead, TCE suppressed hepatic expression of genes involved in IL-6 signaling (Il6r, gp130, and Egr1). Linear regression analysis confirmed liver histopathology in the TCE-treated mice correlated with decreased expression of Il6r. A toxicodynamic model was developed to estimate the effects of TCE on IL-6 signaling and liver pathology under different levels of exposure and rates of repair. This study underlined the importance of longitudinal studies in mechanistic evaluations of immuntoxicants. It showed that later-occurring liver pathology caused by TCE was associated with early suppression of hepatoprotection rather than an increase in conventional pro-inflammatory events. This information was used to create a novel toxicodynamic model of IL-6-mediated TCE-induced liver inflammation. - Highlights: • We developed a toxicodynamic model to study effects of trichloroethylene on liver. • We examined protective as well as pro-inflammatory events in the liver. • Trichloroethylene inhibits IL-6 production by macrophages. • Trichloroethylene

  10. Toluene formation from coadsorbed methanethiol and benzenethiol on the Ni(III) surface

    SciTech Connect

    Kane, S.M.; Gland, J.L.; Huntley, D.R.

    1996-04-17

    We report our observation of interspecies carbon-carbon bond formation during the reaction of coadsorbed methanethiol and benzenethiol on the Ni(III) surface. Toluene formation has been detected between 250 and 320 K in addition to methane and benzene, the hydrogenolysis products. Increased concentrations of benzenethiolate and methanethiolate, the surface intermediates, increase the amount of toluene formed. Water formation below the toluene formation temperature decreases surface hydrogen, causing toluene yield to increase substantially compared to methane and benzene yield. Toluene increases up to a factor of 20 were observed for high coadsorbed coverages. Together, these results clearly indicate that competition between hydrogen addition and alkylation controls toluene formation. 28 refs., 3 figs.

  11. Persistent reactive airway dysfunction syndrome after exposure to toluene diisocyanate.

    PubMed Central

    Luo, J C; Nelsen, K G; Fischbein, A

    1990-01-01

    Two police officers developed asthma like illness after a single but prolonged exposure to toluene diisocyanate (TDI) by being in the immediate vicinity of a tank car that had overturned on a highway. One officer experienced upper and lower respiratory tract symptoms with chest tightness about 4.5 hours after initial exposure. Shortness of breath, cough, and wheezing were noted the following day. The other experienced symptoms immediately on exposure, developed shortness of breath 20 minutes later, and presented with wheezing four hours after that. Follow up examinations over seven years showed persistence of respiratory symptoms and continuation of airway hyperreactivity requiring treatment. PMID:2159772

  12. Kinetic Modeling of Toluene Oxidation for Surrogate Fuel Applications

    SciTech Connect

    Frassoldati, A; Mehl, M; Fietzek, R; Faravelli, T; Pitz, W J; Ranzi, E

    2009-04-21

    New environmental issues, like the effect of combustion-generated greenhouse gases, provide motivation to better characterize oxidation of hydrocarbons. Transportation, in particular, significantly contributes to energy consumption and CO{sub 2} emissions. Kinetic studies about the combustion of fuels under conditions typical of internal combustion engines provides important support to improve mechanism formulation and to eventually provide better computational tools that can be used to increase the engine performance. It is foreseeable that at least in the next 30 years the main transportation fuels will be either gasoline or diesel. Unfortunately, these fuels are very complex mixtures of many components. Moreover, their specifications and performance requirements significantly change the composition of these fuels: gasoline and diesel mixtures are different if coming from different refineries or they are different from winter to summer. At the same time a fuel with a well defined and reproducible composition is needed for both experimental and modeling work. In response to these issues, surrogate fuels are proposed. Surrogate fuels are defined as mixtures of a small number of hydrocarbons whose relative concentrations is adjusted in order to approximate the chemical and physical properties of a real fuel. Surrogate fuels are then very useful both for the design of reproducible experimental tests and also for the development of reliable kinetic models. The primary reference fuels (PRF) are a typical and old example of surrogate fuel: n-heptane and iso-octane mixtures are used to reproduce antiknock propensity of complex mixtures contained in a gasoline. PRFs are not able to surrogate gasoline in operating conditions different from standard ones and new surrogates have been recently proposed. Toluene is included in all of them as a species able to represent the behavior of aromatic compounds. On the other side, the toluene oxidation chemistry is not so well

  13. Degradation of off-gas toluene in continuous pyrite Fenton system.

    PubMed

    Choi, Kyunghoon; Bae, Sungjun; Lee, Woojin

    2014-09-15

    Degradation of off-gas toluene from a toluene reservoir and a soil vapor extraction (SVE) process was investigated in a continuous pyrite Fenton system. The removal of off-gas toluene from the toluene reservoir was >95% by 8h in the pyrite Fenton system, while it was ∼97 % by 3h in classic Fenton system and then rapidly decreased to initial level by 8h. Continuous consumption of low Fe(II) concentration dissolved from pyrite surface (0.05-0.11 mM) was observed in the pyrite Fenton system, which can lead to the effective and successful removal of the gas-phase toluene due to stable production of OH radical (OH). Inhibitor and spectroscopic test results showed that OH was a dominant radical that degraded gas-phase toluene during the reaction. Off-gas toluene from the SVE process was removed by 96% in the pyrite Fenton system, and remnant toluene from rebounding effect was treated by 99%. Main transformation products from toluene oxidation were benzoic acid (31.4%) and CO2 (38.8%) at 4h, while traces of benzyl alcohol (1.3%) and benzaldehyde (0.7%) were observed. Maximum operation time of continuous pyrite Fenton system was estimated to be 56-61 d and its optimal operation time achieving emission standard was 28.9 d. PMID:25125037

  14. [Experimental study on DC corona radical shower for the removal of toluene].

    PubMed

    Zhou, Yongping; Gao, Xiang; Wu, Zuliang; Luo, Zhongyang; Wei, Enzong; Ni, Mingjiang; Cen, Kefa

    2003-07-01

    Using DC corona radicals shower to decompose toluene in air, different parameters were studied, such as the concentration of toluene, temperature, voltage, humidity and the settled time. The results showed that the fall of temperature and appropriate humidity can increase the decomposing efficiency of toluene; the efficiency decreased with the increasing of the voltage; the settled time was longer, the decomposing efficiency was higher, but the energy efficiency decreased. Increasing the concentration of toluene made the removal efficiency lower, but in the same time, made the energy efficiency higher. The experiment built a good basis for researching radicals decompose PAHs(dioxins etc.). PMID:14551974

  15. Diversity of Five Anaerobic Toluene-Degrading Microbial Communities Investigated Using Stable Isotope Probing

    PubMed Central

    Sun, Weimin

    2012-01-01

    Time-series DNA-stable isotope probing (SIP) was used to identify the microbes assimilating carbon from [13C]toluene under nitrate- or sulfate-amended conditions in a range of inoculum sources, including uncontaminated and contaminated soil and wastewater treatment samples. In all, five different phylotypes were found to be responsible for toluene degradation, and these included previously identified toluene degraders as well as novel toluene-degrading microorganisms. In microcosms constructed from granular sludge and amended with nitrate, the putative toluene degraders were classified in the genus Thauera, whereas in nitrate-amended microcosms constructed from a different source (agricultural soil), microorganisms in the family Comamonadaceae (genus unclassified) were the key putative degraders. In one set of sulfate-amended microcosms (agricultural soil), the putative toluene degraders were identified as belonging to the class Clostridia (genus Desulfosporosinus), while in other sulfate-amended microcosms, the putative degraders were in the class Deltaproteobacteria, within the family Syntrophobacteraceae (digester sludge) or Desulfobulbaceae (contaminated soil) (genus unclassified for both). Partial benzylsuccinate synthase gene (bssA, the functional gene for anaerobic toluene degradation) sequences were obtained for some samples, and quantitative PCR targeting this gene, along with SIP, was further used to confirm anaerobic toluene degradation by the identified species. The study illustrates the diversity of toluene degraders across different environments and highlights the utility of ribosomal and functional gene-based SIP for linking function with identity in microbial communities. PMID:22156434

  16. Evaluation of simultaneous biodegradation of methane and toluene in landfill covers.

    PubMed

    Su, Yao; Zhang, Xuan; Wei, Xiao-Meng; Kong, Jiao-Yan; Xia, Fang-Fang; Li, Wei; He, Ruo

    2014-06-15

    The biodegradation of CH4 and toluene in landfill cover soil (LCS) and waste biocover soil (WBS) was investigated with a serial toluene concentration in the headspace of landfill cover microcosms in this study. Compared with the LCS sample, the higher CH4 oxidation activity and toluene-degrading capacity occurred in the WBS sample. The co-existence of toluene in landfill gas would positively or negatively affect CH4 oxidation, mainly depending on the toluene concentrations and exposure time. The nearly complete inhibition of toluene on CH4 oxidation was observed in the WBS sample at the toluene concentration of ∼ 80,000 mg m(-3), which was about 10 times higher than that in the LCS sample. The toluene degradation rates in both landfill covers fitted well with the Michaelis-Menten model. These findings showed that WBS was a good alternative landfill cover material to simultaneously mitigate emissions of CH4 and toluene from landfills to the atmosphere. PMID:24801894

  17. Absorption of gaseous toluene in aqueous solutions of some kinds of fluorocarbon surfactant.

    PubMed

    Xiao, Xiao; Yan, Bo; Fu, Jiamo; Xiao, Xianming

    2015-01-01

    A self-designed device was applied to treat a simulated exhaust gas loaded with toluene by aqueous solutions of five kinds of fluorocarbon surfactant (FS-3100, FS-22, FSN-100, FSO-100 and FSG) under the controlled laboratory conditions. The simulated exhaust gas is generated by a mixture of clean air and toluene vapor, and its toluene concentration can be controlled by changing the volume ratio of the inlet air to the vapor. Two mass transfer methods: liquid-liquid transfer and gas-liquid transfer, were compared for their toluene saturation capacities of these absorbent solutions, and it was found that more toluene was dissolved by the liquid-liquid transfer than by the gas-liquid transfer. According to the saturation capacities of these absorbent solutions and their Henry's Constants, FSO-100 is the best absorbent to treat the simulated exhaust gas and was selected for further experiments. The FSO-100 absorbent solution with a concentration of 0.1 % shows an efficient absorption to the simulated exhaust gas, with a toluene saturation capacity of 4.2 mg/g. Heating distillation (90- 95 oC) is highly efficient to recover toluene from the FSO-100 absorbent solution as well as regenerate it. A toluene recovery of about 85 % was achieved. The regenerated absorption solution can keep its initial toluene absorption capacity during the reuse. PMID:25946961

  18. Biotransformation of nitrobenzene by bacteria containing toluene degradative pathways

    SciTech Connect

    Haigler, B.E.; Spain, J.C. )

    1991-11-01

    Nonpolar nitroaromatic compounds have been considered resistant to attack by oxygenases because of the electron withdrawing properties of the nitro group. The authors have investigate the ability of seven bacterial strains containing toluene degradative pathways to oxidize nitrobenzene. Cultures were induced with toluene vapor prior to incubation with nitrobenzene, and products were identified by high-performance liquid chromatography and gas chromatography-mass spectrometry. Pseudomonas cepacia G4 and a strain of Pseudomonas harboring the TOL plasmid (pTN2) did not transform nitrobenzene. Cells of Pseudomonas putida F1 and Pseudomonas sp. strain JS150 converted nitrobenzene to 3-nitrocatechol. Transformation of nitrobenzene in the presence of {sup 18}O{sub 2} indicated that the reaction in JS150 involved the incorporation of both atoms of oxygen in the 3-nitrocatechol, which suggests a dioxygenase mechanism. P. putida 39/D, a mutant strain of P. putida F1, converted nitrobenzene to a compound tentatively identified as cis-1, 2-dihydroxy-3-nitrocyclohexa-3, 5-diene. This compound was rapidly converted to 3-nitrocatechol by cells of strain JS150. Cultures of Pseudomonas mendocina KR-1 converted nitrobenzene to a mixture of 3- and 4-nitrophenol (10 and 63%, respectively). Pseudomonas pickettii PKO1 converted nitrobenzene to 3- and 4-nitrocatechol via 3- and 4-nitrophenol. The nitrocatechols were slowly degraded to unidentified metabolites. Nitrobenzene did not serve as an inducer for the enzymes that catalyzed its oxidation.

  19. Phenol- and Toluene-Degrading Microbial Populations from an Aquifer in Which Successful Trichloroethene Cometabolism Occurred

    PubMed Central

    Fries, M. R.; Forney, L. J.; Tiedje, J. M.

    1997-01-01

    We characterized the bacterial populations that grew in a Moffett Field, Calif., aquifer following three sequential field tests of phenol- or toluene-driven cometabolism of trichloroethene (TCE). Reducing the toluene and phenol concentrations in most-probable-number (MPN) tubes from 50 to 5 ppm increased the population density measured for these degraders by 1.5 and 1 log units, respectively, suggesting that natural populations might be quite sensitive to these substrates. Phenol and toluene degraders were isolated from the terminal MPN dilution tubes; 63 genetically distinct strains were identified among the 273 phenol- and toluene-degrading isolates obtained. TCE was cometabolized by 60% of the genetically distinct strains. Most strains (57%) grew on both phenol and toluene, and 78% of these strains hybridized to the toluene ortho-monooxygenase (TOM) probe. None of the strains hybridized to probes from the four other toluene oxygenase pathways. Gram-positive strains comprised 30% of the collection; all of these grew on phenol, and 47% of them also grew on toluene, but none hybridized to the TOM probe. Among the gram-negative strains, 86% of those that grew on both toluene and phenol hybridized to the TOM probe, while only 5% of those that were TOM-positive grew on toluene alone. A larger proportion of TCE degraders was found among gram-negative than gram-positive strains and among organisms that grew on phenol than those that grew on toluene. Hybridization of strains to the TOM probe was somewhat predictive of their TCE-cometabolizing ability, especially for strains isolated on toluene, but there was also a significant number (20%) of strains that hybridized to the TOM probe but were poor TCE cooxidizers. No Moffett Field isolates were as effective as Burkholderia cepacia G4 in cooxidizing TCE. Most of the aquifer strains ranged from moderately effective to ineffective in TCE cooxidation. Such populations, however, apparently accounted for the successful phenol

  20. Phototrophic utilization of toluene under anoxic conditions by a new strain of blastochloris sulfoviridis

    PubMed

    Zengler; Heider; Rossello-Mora; Widdel

    1999-10-01

    The capacity of anoxygenic phototrophic bacteria to utilize aromatic hydrocarbons was investigated in enrichment cultures with toluene. When mineral medium with toluene (provided in an inert carrier phase) was inoculated with activated sludge and incubated under infrared illumination (> 750 nm), a red-to-brownish culture developed. Agar dilution series indicated the dominance of two types of phototrophic bacteria. One type formed red colonies, had rod-shaped cells with budding division, and grew on benzoate but not on toluene. The other type formed yellow-to-brown colonies, had oval cells, and utilized toluene and benzoate. One strain of the latter type, ToP1, was studied in detail. Sequence analysis of the 16S rRNA gene and DNA-DNA hybridization indicated an affiliation of strain ToP1 with the species Blastochloris sulfoviridis, a member of the alpha-subclass of Proteobacteria. However, the type strain (DSM 729) of Blc. sulfoviridis grew neither on toluene nor on benzoate. Light-dependent consumption of toluene in the presence of carbon dioxide and formation of cell mass by strain ToP1 were demonstrated in quantitative growth experiments. Strain ToP1 is the first phototrophic bacterium shown to utilize an aromatic hydrocarbon. In the supernatant of toluene-grown cultures and in cell-free extracts incubated with toluene and fumarate, the formation of benzylsuccinate was detected. These findings indicate that the phototrophic bacterium activates toluene anaerobically by the same mechanism that has been reported for denitrifying and sulfate-reducing bacteria. The natural abundance of phototrophic bacteria with the capacity for toluene utilization was examined in freshwater habitats. Counting series revealed that up to around 1% (1.8 x 10(5) cells per gram dry mass of sample) of the photoheterotrophic population cultivable with acetate grew on toluene. PMID:10525736

  1. Isolation and characterization of a novel toluene-degrading, sulfate-reducing bacterium.

    PubMed Central

    Beller, H R; Spormann, A M; Sharma, P K; Cole, J R; Reinhard, M

    1996-01-01

    A novel sulfate-reducing bacterium isolated from fuel-contaminated subsurface soil, strain PRTOL1, mineralizes toluene as the sole electron donor and carbon source under strictly anaerobic conditions. The mineralization of 80% of toluene carbon to CO2 was demonstrated in experiments with [ring-U-14C]toluene; 15% of toluene carbon was converted to biomass and nonvolatile metabolic by-products, primarily the former. The observed stoichiometric ratio of moles of sulfate consumed per mole of toluene consumed was consistent with the theoretical ratio for mineralization of toluene coupled with the reduction of sulfate to hydrogen sulfide. Strain PRTOL1 also transforms o- and p-xylene to metabolic products when grown with toluene. However, xylene transformation by PRTOL1 is slow relative to toluene degradation and cannot be sustained over time. Stable isotope-labeled substrates were used in conjunction with gas chromatography-mass spectrometry to investigate the by-products of toluene and xylene metabolism. The predominant by-products from toluene, o-xylene, and p-xylene were benzylsuccinic acid, (2-methylbenzyl)succinic acid, and 4-methylbenzoic acid (or p-toluic acid), respectively. Metabolic by-products accounted for nearly all of the o-xylene consumed. Enzyme assays indicated that acetyl coenzyme A oxidation proceeded via the carbon monoxide dehydrogenase pathway. Compared with the only other reported toluene-degrading, sulfate-reducing bacterium, strain PRTOL1 is distinct in that it has a novel 16S rRNA gene sequence and was derived from a freshwater rather than marine environment. PMID:8919780

  2. Chloroform and trichloroethylene uptake from water into human skin in vitro: Kinetics and risk implications

    SciTech Connect

    Bogen, K.T.; Keating, G.A.; Vogel, J.S.

    1995-03-01

    A model recently proposed by the US Environmental Protection Agency (EPA) predicts that short-term dermal uptakes of organic environmental water contaminants are proportional to the square root of exposure time. The model appears to underestimate dermal uptake, based on very limited in vivo uptake data obtained primarily using human subjects. To further assess this model, we examined in vitro dermal uptake kinetics for aqueous organic chemicals using accelerator mass spectrometry (AMS). Specifically, we examined the kinetics of in vitro dermal uptake of {sup 14}C-labeled chloroform and trichloroethylene from dilute (5-ppb) aqueous solutions using full-thickness human cadaver skin exposed for ({le}1 hr).

  3. Photo-activated luminescence sensor and method of detecting trichloroethylene and related volatile organochloride compounds

    DOEpatents

    Dinh, T.V.

    1996-06-11

    A sensor for detecting trichloroethylene and related volatile organochloride compounds uses a photo-activator that produces a photo-product complex with the contaminant. Characteristics of the light emitted from the complex will indicate the presence of the contaminant. A probe containing the photo-activator has an excitation light interface and a contaminant interface. One particular embodiment uses a porous membrane as the contaminant interface, so that the contaminant can migrate there through to the photo-activator and thereby form the complex. 23 figs.

  4. Photo-activated luminescence sensor and method of detecting trichloroethylene and related volatile organochloride compounds

    DOEpatents

    Dinh, Tuan V.

    1996-01-01

    A sensor for detecting trichloroethylene and related volatile organochloride compounds uses a photo-activator that produces a photo-product complex with the contaminant. Characteristics of the light emitted from the complex will indicate the presence of the contaminant. A probe containing the photo-activator has an excitation light interface and a contaminant interface. One particular embodiment uses a porous membrane as the contaminant interface, so that the contaminant can migrate therethrough to the photo-activator and thereby form the complex.

  5. Microbial degradation of trichloroethylene in the rhizosphere: potential application to biological remediation of waste sites.

    PubMed Central

    Walton, B T; Anderson, T A

    1990-01-01

    The possibility that vegetation may be used to actively promote microbial restoration of chemically contaminated soils was tested by using rhizosphere and nonvegetated soils collected from a trichloroethylene (TCE)-contaminated field site. Biomass determinations, disappearance of TCE from the headspace of spiked soil slurries, and mineralization of [14C]TCE to 14CO2 all showed that microbial activity is greater in rhizosphere soils and that TCE degradation occurs faster in the rhizosphere than in the edaphosphere. Thus, vegetation may be an important variable in the biological restoration of surface and near-surface soils. PMID:2339867

  6. System for In-Situ Detection of Plant Exposure to Trichloroethylene (TCE)

    NASA Technical Reports Server (NTRS)

    Lewis, Mark D. (Inventor); Anderson, Daniel J. (Inventor); Newman, Lee A. (Inventor); Keith, Amy G. (Inventor)

    2013-01-01

    A system detects a plant's exposure to trichloroethylene (TCE) through plant leaf imaging. White light impinging upon a plant's leaf interacts therewith to produce interacted light. A detector is positioned to detect at least one spectral band of the interacted light. A processor coupled to the detector performs comparisons between photonic energy of the interacted light at the one or more spectral bands thereof and reference data defining spectral responses indicative of leaf exposure to TCE. An output device coupled to the processor provides indications of the comparisons.

  7. [Photocatalytic Degradation of Gaseous Toluene by a Photo-Fenton Reaction].

    PubMed

    Zheng, Si-can; Chen, Tian-hu; Liu, Hai-bo; Zou, Xue-hua; Zhu, Cheng-zhu; Chen, Dong

    2015-10-01

    In this study, the performance of photo-Fenton reaction on decomposition of toluene was investigated by a flowing column using toluene as a representative of volatile organic pollutants (VOCs). The effects of initial pH, H2O2 concentration, Fe2+ concentration, initial concentration of toluene on degradation of toluene by photo-Fenton reaction were evaluated. Mass spectrometry and gas chromatograph were utilized to detect the products. The results showed that the introduction of UV greatly enhanced the Fenton reaction by improving the generation of hydroxyl radicals. When the initial concentration of toluene was 260 mg x m(-3), the toluene removal can achieve 98% under the following experimental conditions: initial pH = 3.0, H2O2 20 mmol x L(-1), Fe2+ 0.3 mmol x L(-1). Furthermore, no other intermediate except CO2 was detected in the reaction that photocatalytic degradation of toluene in waste gas by the photo-Fenton, which indicates all the degraded toluene was mineralized into CO2. PMID:26841589

  8. EVALUATING THE NMDA-GLUTAMATE RECEPTOR AS A SITE OF ACTION FOR TOLUENE, IN VIVO

    EPA Science Inventory

    In vitro, toluene disrupts the function of NMDA-glutamate receptors, indicating that effects on NMDA receptor function may contribute to toluene neurotoxicity. NMDA-glutamate receptors are widely present in the visual system and contribute to pattern-elicited visual evoked potent...

  9. Anaerobic degradation of toluene and o-xylene by a methanogenic consortium.

    PubMed Central

    Edwards, E A; Grbić-Galić, D

    1994-01-01

    Toluene and o-xylene were completely mineralized to stoichiometric amounts of carbon dioxide, methane, and biomass by aquifer-derived microorganisms under strictly anaerobic conditions. The source of the inoculum was creosote-contaminated sediment from Pensacola, Fla. The adaptation periods before the onset of degradation were long (100 to 120 days for toluene degradation and 200 to 255 days for o-xylene). Successive transfers of the toluene- and o-xylene-degrading cultures remained active. Cell density in the cultures progressively increased over 2 to 3 years to stabilize at approximately 10(9) cells per ml. Degradation of toluene and o-xylene in stable mixed methanogenic cultures followed Monod kinetics, with inhibition noted at substrate concentrations above about 700 microM for o-xylene and 1,800 microM for toluene. The cultures degraded toluene or o-xylene but did not degrade m-xylene, p-xylene, benzene, ethylbenzene, or naphthalene. The degradative activity was retained after pasteurization or after starvation for 1 year. Degradation of toluene and o-xylene was inhibited by the alternate electron acceptors oxygen, nitrate, and sulfate. Degradation was also inhibited by the addition of preferred substrates such as acetate, H2, propionate, methanol, acetone, glucose, amino acids, fatty acids, peptone, and yeast extract. These data suggest that the presence of natural organic substrates or contaminants may inhibit anaerobic degradation of pollutants such as toluene and o-xylene at contaminated sites. Images PMID:8117084

  10. Behavioral Effects of Sub-Acute Inhalation of Toluene in Adult Rats

    EPA Science Inventory

    Reports of behavioral effects of repeated inhalation of toluene in rats have Yielded inconsistent fmdings. A recent study from this laboratory (Beasley et al., 2010) observed that after 13 weeks of inhaled toluene ("sub-chronic" exposure scenario), rats showed mild but persiste...

  11. Examining the Impact of an Updated Toluene Mechanism on Air Quality in the Eastern US

    EPA Science Inventory

    Model simulations were performed using the CB05 chemical mechanism containing the base and an updated toluene mechanisms for the eastern US. The updated toluene mechanism increased monthly mean 8-hr ozone by 1.0-2.0 ppbv in urban areas of Chicago, the northeast US, Detroit, Cleve...

  12. Transformation of pWWO in Rhizobium leguminosarum DPT to Engineer Toluene Degrading Ability for Rhizoremediation.

    PubMed

    Goel, Garima; Pandey, Piyush; Sood, Anchal; Bisht, Sandeep; Maheshwari, D K; Sharma, G D

    2012-06-01

    Rhizoremediation of organic xenobiotics is based on interactions between plants and their associated micro-organisms. The present work was designed to engineer a bacterial system having toluene degradation ability along with plant growth promoting characteristics for effective rhizoremediation. pWWO harboring the genes responsible for toluene breakdown was isolated from Pseudomonas putida MTCC 979 and successfully transformed in Rhizobium DPT. This resulted in a bacterial strain (DPT(T)) which had the ability to degrade toluene as well as enhance growth of host plant. The frequency of transformation was recorded 5.7 × 10(-6). DPT produced IAA, siderophore, chitinase, HCN, ACC deaminase, solubilized inorganic phosphate, fixed atmospheric nitrogen and inhibited the growth of Fusarium oxysporum and Macrophomina phaseolina in vitro. During pot assay, 50 ppm toluene in soil was found to inhibit the germination of Cajanus cajan seeds. However when the seeds bacterized with toluene degrading P. putida or R. leguminosarum DPT were sown in pots, again no germination was observed. Non-bacterized as well as bacterized seeds germinated successfully in toluene free soil as control. The results forced for an alternative mode of application of bacteria for rhizoremediation purpose. Hence bacterial suspension was mixed with soil having 50 ppm of toluene. Germination index in DPT treated soil was 100% while in P. putida it was 50%. Untreated soil with toluene restricted the seeds to germinate. PMID:23729882

  13. Construction and use of recombinant Escherichia coli strains for the synthesis of toluene cis-glycol.

    PubMed

    Wahbi, L P; Gokhale, D; Minter, S; Stephens, G M

    1996-09-01

    The toluene dioxygenase genes derived from Pseudomonas putida NCIMB 11767 were subcloned from a previously constructed recombinant plasmid, pIG, using pUC18 as the cloning vector and E. coli TG2 as the host strain. The resulting strain, E. coli TG2 (p1/1), produced toluene cis-glycol when grown in LB broth or minimal medium in the presence of toluene. Restriction mapping and partial DNA sequencing provided evidence for the presence of ORFs with extensive homology to parts of the tod operon from P. putida F1. The clones exhibited some residual toluene cis-glycol dehydrogenase activity which resulted in the formation of small amounts of 3-methylcatechol. Expression of the dioxygenase was induced by toluene, but was not directed by the lac promoter within the cloning vector. The clones were assessed for toluene cis-glycol production in pH-controlled batch cultures, and the maximum product concentration obtained was 1.02 g l-1. Product formation was dependent upon the presence of glucose in the culture medium. Although the substrate was toxic, the biotransformation was apparently limited by the supply of toluene. The results suggest that it should be possible to improve toluene cis-glycol production by recombinants substantially by improving both the strain and fermentation process. PMID:8987488

  14. Use of Selective Inhibitors and Chromogenic Substrates to Differentiate Bacteria Based on Toluene Oxygenase Activity

    SciTech Connect

    Keener, William Kelvin; Schaller, Kastli Dianne; Walton, Michelle Rene; Partin, Judy Kaye; Watwood, Mary Elizabeth; Smith, William Aaron; Chingenpeel, S. R.

    2001-09-01

    In whole-cell studies, two alkynes, 1-pentyne and phenylacetylene, were selective, irreversible inhibitors of monooxygenase enzymes in catabolic pathways that permit growth of bacteria on toluene. 1-Pentyne selectively inhibited growth of Burkholderia cepacia G4 (toluene 2-monooxygenase [T2MO] pathway) and B. pickettii PKO1 (toluene 3-monooxygenase [T3MO] pathway) on toluene, but did not inhibit growth of bacteria expressing other pathways. In further studies with strain G4, chromogenic transformation of a,a,a-Trifluoro-m-cresol (TFC) was irreversibly inhibited by 1-pentyne, but the presence of phenol prevented this inhibition. Transformation of catechol by G4 was unaffected by 1-pentyne. With respect to the various pathways and bacteria tested, phenylacetylene selectively inhibited growth of Pseudomonas mendocina KR1 (toluene 4-monooxygenase [T4MO] pathway) on toluene, but not on p-cresol. An Escherichia coli transformant expressing T4MO transformed indole or naphthalene in chromogenic reactions, but not after exposure to phenylacetylene. The naphthalene reaction remained diminished in phenylacetylene-treated cells relative to untreated cells after phenylacetylene was removed, indicating irreversible inhibition. These techniques were used to differentiate toluene-degrading isolates from an aquifer. Based on data generated with these indicators and inhibitors, along with results from Biolog analysis for sole carbon source oxidation, the groundwater isolates were assigned to eight separate groups, some of which apparently differ in their mode of toluene catabolism.

  15. NEUROPHYSIOLOGICAL EFFECTS OF 30 DAY CHRONIC EXPOSURE TO TOLUENE IN RATS

    EPA Science Inventory

    Long-Evans hooded rats were exposed to 1000 ppm toluene or 0 ppm toluene 6 hr/day, 5 days/week for 30 days. Following removal from the exposure conditions (18-26 hr) flash-evoked potentials were recorded to paired light flashes and pentylenetetrazol (PTZ) seizure properties were ...

  16. EVALUATING MOLECULAR SITES OF ACTION FOR TOLUENE USING AN IN VIVO MODEL.

    EPA Science Inventory


    In vitro studies have demonstrated that toluene disrupts the function of several ion channels localized in the brain, including the NMDA-glutamate receptor. This has led to the hypothesis that effects on ion channel function may contribute to toluene neurotoxicity, CNS depres...

  17. Effects of activated carbon fibre-supported metal oxide characteristics on toluene removal.

    PubMed

    Liu, Zhen-Shu; Peng, Yu-Hui; Li, Wen-Kai

    2014-01-01

    Few studies have investigated the use of activated carbon fibres (ACFs) impregnated with metal oxides for the catalytic oxidation of volatile organic compounds (VOCs). Thus, the effects of the ACF-supported metal oxides on toluene removal are determined in this study. Three catalysts, namely, Ce, Mn, and Cu, two pretreatment solutions NaOH and H2O2, and three reaction temperatures of 250 degrees C, 300 degrees C, and 350 degrees C, were employed to determine toluene removal. The composition and morphology of the catalysts were analysed using Brunauer-Emmett-Teller (BET), transmission electron microscope (TEM), inductively coupled plasma (ICP), X-ray photoelectron spectroscopy (XPS), Fourier-transform infrared spectrometer (FTIR), and thermo-gravimetric analyser (TGA) to study the effects of the catalyst's characteristics on toluene removal. The results demonstrated that the metal catalysts supported on the ACFs could significantly increase toluene removal. The Mn/ACFs and Cu/ACFs were observed to be most active in toluene removal at a reaction temperature of 250 degrees C with 10% oxygen content. Moreover, the data also indicated that toluene removal was slightly improved after pretreating the ACFs with NaOH and H2O2. The results suggested that surface-metal loading and the surface characteristics of the ACFs were the determinant parameters for toluene removal. Furthermore, the removal of toluene over Mn/ACFs-H202 decreased when the reaction temperature considered was > 300 degrees C. PMID:24701949

  18. Effect of isobutanol on toluene biodegradation in nitrate amended, sulfate amended and methanogenic enrichment microcosms.

    PubMed

    Jayamani, Indumathy; Cupples, Alison M

    2013-09-01

    Isobutanol is an alternate fuel additive that is being considered because of economic and lower emission benefits. However, future gasoline spills could result in co-contamination of isobutanol with gasoline components such as benzene, toluene, ethyl-benzene and xylene. Hence, isobutanol could affect the degradability of gasoline components thereby having an effect on contaminant plume length and half-life. In this study, the effect of isobutanol on the biodegradation of a model gasoline component (toluene) was examined in laboratory microcosms. For this, toluene and isobutanol were added to six different toluene degrading laboratory microcosms under sulfate amended, nitrate amended or methanogenic conditions. While toluene biodegradation was not greatly affected in the presence of isobutanol in five out of the six different experimental sets, toluene degradation was completely inhibited in one set of microcosms. This inhibition occurred in sulfate amended microcosms constructed with inocula from wastewater treatment plant activated sludge. Our data suggest that toluene degrading consortia are affected differently by isobutanol addition. These results indicate that, if co-contamination occurs, in some cases the in situ half-life of toluene could be significantly extended. PMID:23224907

  19. Soot formation during combustion of unsupported methanol/toluene mixture droplets in microgravity

    NASA Technical Reports Server (NTRS)

    Jackson, G. S.; Avedisian, C. T.; Yang, J. C.

    1991-01-01

    Results are reported of an experimental study tracing the influence of liquid composition on soot formation and the burning rate of a droplet composed of a binary miscible mixture of liquids. The mixture components represented a highly sooting fuel, toluene, and a nonsooting fuel, methanol. The toluene concentration in methanol was shown to dramatically influence flame luminosity and soot production. Neither burning rates nor a propensity for flame extinction appeared to be significantly affected by toluene mixture fractions. Five-percent toluene mixture droplets behaved like pure methanol droplets in terms of burning rate, lack of flame luminosity, and extinction. Increasing the toluene concentration in the droplets to 25 percent increased flame luminosity, yet no visible soot agglomerates were observed. The 50-percent-mixture droplets burned with highly luminous flames and large amounts of soot agglomerates collecting inside the flame. All the mixture droplets showed burning rates similar to those of pure methanol and likewise exhibited flame extinction before complete droplet vaporization.

  20. DETERMINATION OF SECONDARY ORGANIC AEROSOL PRODUCTS FROM THE PHOTOOXIDATION OF TOLUENE AND THEIR IMPLICATIONS IN AMBIENT PM2.5

    EPA Science Inventory

    Laboratory study was carried out to investigate the secondary organic aerosol products from photooxidation of the aromatic hydrocarbon toluene. The laboratory experiments consisted of irradiating toluene/propylene/NOX/air mixtures in a smog chamber operated in the dynamic mode...

  1. MICROBIAL DEGRADATION OF TOLUENE UNDER SULFATE-REDUCING CONDITIONS AND THE INFLUENCE OF IRON ON THE PROCESS

    EPA Science Inventory

    Toluene degradation occurred concomitantly with sulfate reduction in anaerobic microcosms inoculated with contaminated subsurface soil from an aviation fuel storage facility near the Patuxent River (MD). imilar results were obtained for enrichment cultures in which toluene was th...

  2. Modeling the toxicokinetics of 24-hour toluene exposure in rats, impact of activity patterns and enzyme induction

    EPA Science Inventory

    Toluene, a solvent used in numerous consumer and industrial applications, exerts its critical effects on the brain and nervous system following inhalation exposure. Our previously published PBPK model successfully predicted toluene concentrations in blood and brain over a range o...

  3. Affinity for risky behaviors following prenatal and early childhood exposure to tetrachloroethylene (PCE)-contaminated drinking water: a retrospective cohort study

    PubMed Central

    2011-01-01

    Background Many studies of adults with acute and chronic solvent exposure have shown adverse effects on cognition, behavior and mood. No prior study has investigated the long-term impact of prenatal and early childhood exposure to the solvent tetrachloroethylene (PCE) on the affinity for risky behaviors, defined as smoking, drinking or drug use as a teen or adult. Objectives This retrospective cohort study examined whether early life exposure to PCE-contaminated drinking water influenced the occurrence of cigarette smoking, alcohol consumption, and drug use among adults from Cape Cod, Massachusetts. Methods Eight hundred and thirty-one subjects with prenatal and early childhood PCE exposure and 547 unexposed subjects were studied. Participants completed questionnaires to gather information on risky behaviors as a teenager and young adult, demographic characteristics, other sources of solvent exposure, and residences from birth through 1990. PCE exposure was estimated using the U.S. EPA's water distribution system modeling software (EPANET) that was modified to incorporate a leaching and transport model to estimate PCE exposures from pipe linings. Results Individuals who were highly exposed to PCE-contaminated drinking water during gestation and early childhood experienced 50-60% increases in the risk of using two or more major illicit drugs as a teenager or as an adult (Relative Risk (RR) for teen use = 1.6, 95% CI: 1.2-2.2; and RR for adult use = 1.5, 95% CI: 1.2-1.9). Specific drugs for which increased risks were observed included crack/cocaine, psychedelics/hallucinogens, club/designer drugs, Ritalin without a prescription, and heroin (RRs:1.4-2.1). Thirty to 60% increases in the risk of certain smoking and drinking behaviors were also seen among highly exposed subjects. Conclusions The results of this study suggest that risky behaviors, particularly drug use, are more frequent among adults with high PCE exposure levels during gestation and early childhood

  4. Risk of breast cancer following exposure to tetrachloroethylene-contaminated drinking water in Cape Cod, Massachusetts: reanalysis of a case-control study using a modified exposure assessment

    PubMed Central

    2011-01-01

    Background Tetrachloroethylene (PCE) is an important occupational chemical used in metal degreasing and drycleaning and a prevalent drinking water contaminant. Exposure often occurs with other chemicals but it occurred alone in a pattern that reduced the likelihood of confounding in a unique scenario on Cape Cod, Massachusetts. We previously found a small to moderate increased risk of breast cancer among women with the highest exposures using a simple exposure model. We have taken advantage of technical improvements in publically available software to incorporate a more sophisticated determination of water flow and direction to see if previous results were robust to more accurate exposure assessment. Methods The current analysis used PCE exposure estimates generated with the addition of water distribution modeling software (EPANET 2.0) to test model assumptions, compare exposure distributions to prior methods, and re-examine the risk of breast cancer. In addition, we applied data smoothing to examine nonlinear relationships between breast cancer and exposure. We also compared a set of measured PCE concentrations in water samples collected in 1980 to modeled estimates. Results Thirty-nine percent of individuals considered unexposed in prior epidemiological analyses were considered exposed using the current method, but mostly at low exposure levels. As a result, the exposure distribution was shifted downward resulting in a lower value for the 90th percentile, the definition of "high exposure" in prior analyses. The current analyses confirmed a modest increase in the risk of breast cancer for women with high PCE exposure levels defined by either the 90th percentile (adjusted ORs 1.0-1.5 for 0-19 year latency assumptions) or smoothing analysis cut point (adjusted ORs 1.3-2.0 for 0-15 year latency assumptions). Current exposure estimates had a higher correlation with PCE concentrations in water samples (Spearman correlation coefficient = 0.65, p < 0.0001) than estimates

  5. Occurrence of mental illness following prenatal and early childhood exposure to tetrachloroethylene (PCE)-contaminated drinking water: a retrospective cohort study

    PubMed Central

    2012-01-01

    Background While many studies of adults with solvent exposure have shown increased risks of anxiety and depressive disorders, there is little information on the impact of prenatal and early childhood exposure on the subsequent risk of mental illness. This retrospective cohort study examined whether early life exposure to tetrachloroethylene (PCE)-contaminated drinking water influenced the occurrence of depression, bipolar disorder, post-traumatic stress disorder, and schizophrenia among adults from Cape Cod, Massachusetts. Methods A total of 1,512 subjects born between 1969 and 1983 were studied, including 831 subjects with both prenatal and early childhood PCE exposure and 547 unexposed subjects. Participants completed questionnaires to gather information on mental illnesses, demographic and medical characteristics, other sources of solvent exposure, and residences from birth through 1990. PCE exposure originating from the vinyl-liner of water distribution pipes was assessed using water distribution system modeling software that incorporated a leaching and transport algorithm. Results No meaningful increases in risk ratios (RR) for depression were observed among subjects with prenatal and early childhood exposure (RR: 1.1, 95% CI: 0.9-1.4). However, subjects with prenatal and early childhood exposure had a 1.8-fold increased risk of bipolar disorder (N = 36 exposed cases, 95% CI: 0.9-1.4), a 1.5-fold increased risk post-traumatic stress disorder (N = 47 exposed cases, 95% CI: 0.9-2.5), and a 2.1-fold increased risk of schizophrenia (N = 3 exposed cases, 95% CI: 0.2-20.0). Further increases in the risk ratio were observed for bipolar disorder (N = 18 exposed cases, RR; 2.7, 95% CI: 1.3-5.6) and post-traumatic stress disorder (N = 18 exposed cases, RR: 1.7, 95% CI: 0.9-3.2) among subjects with the highest exposure levels. Conclusions The results of this study provide evidence against an impact of early life exposure to PCE on the risk of depression. In contrast, the

  6. Determination of thermal diffusion coefficient of nanofluid: Fullerene-toluene

    NASA Astrophysics Data System (ADS)

    Martin, Alain; Bou-Ali, M. Mounir

    2011-05-01

    Thermodiffusion coefficient at fullerene mass concentrations of 0.05%, 0.1%, 0.15%, and 0.2% was established for pure fullerene (C 60) diluted in toluene solutions. For this, the thermogravitational technique has been used in planar configuration with 4 extraction points. The determination of the concentration distribution along the column in steady state is determined by the method of analysis based on density measurements. In order to determine the thermal diffusion coefficient all thermophysical properties such as density, viscosity, thermal expansion coefficient and mass expansion coefficients were determined. All these studies coincide with the importance of the knowledge of the thermophysics and transport properties of the nanofluids to develop new applications and to optimize the existing ones.

  7. Evaluation of a Polyvinyl Toluene Neutron Counter Array

    SciTech Connect

    Robert Hayes

    2008-03-01

    The purpose of this article is to simulate the performance of a neutron detector array for empirical configuration optimization and preliminary algorithm evaluation. Utilizing a compact array of borated Polyvinyl Toluene light pipes and Photomultiplier Tubes, pulse shape analysis, standard spectral histogramming, and multiplicity counting can enable neutron measurements for multiple applications. Results demonstrate that analysis with Monte Carlo N-Particle (MCNP) can be used to obtain a better understanding of field measurement results and aid in algorithm development for unfolding in conjunction with detector optimization. Use of a handheld neutron spectrometer has promise of widespread applicability. By correlating MCNP results with empirical measurements, substantial confidence can be placed on predicting detector response to sufficiently similar spectral sources under alternate experimental configurations. In addition, use of the detector has substantial promise for operational health physics applications.

  8. Differential Effects of Inhaled Toluene on Locomotor Activity in Adolescent and Adult Rats

    PubMed Central

    Batis, Jeffery C.; Hannigan, John H.; Bowen, Scott E.

    2010-01-01

    Inhalant abuse is a world-wide public health concern among adolescents. Most preclinical studies have assessed inhalant effects in adult animals leaving unclear how behavioral effects differ in younger animals. We exposed adolescent (postnatal day [PN] 28) and adult (PN90) male rats to toluene using 1 of 3 exposure patterns. These patterns modeled those reported in toluene abuse in teens and varied concentration, number and length of exposures, as well as the inter-exposure interval. Animals were exposed repeatedly over 12 days to toluene concentrations of 0, 8,000 or 16,000 parts per million (ppm). Locomotor activity was quantified during toluene exposures and for 30 min following completion of the final daily toluene exposure. For each exposure pattern, there were significant toluene concentration-related increases and decreases in locomotor activity compared to the 0-ppm “air” controls at both ages. These changes depended upon when activity was measured – during or following exposure. Compared to adults, adolescents displayed greater locomotor activity on the first day and generally greater increases in activity over days than adults during toluene exposure. Adults displayed greater locomotor activity than adolescents in the “recovery” period following exposure on the first and subsequent days. Age group differences were clearest following the pattern of paced, brief (5-min) repeated binge exposures. The results suggest that locomotor behavior in rats during and following inhalation of high concentrations of toluene depends on age and the pattern of exposure. The results are consistent with dose-dependent shifts in sensitivity and sensitization or tolerance to repeated toluene in the adolescent animals compared to the adult animals. Alternate interpretations are possible and our interpretation is limited by the range of very high concentrations of toluene used. The results imply that both pharmacological and psychosocial factors contribute to the teen

  9. Mesoscale aggregation properties of C60 in toluene and chlorobenzene.

    PubMed

    Guo, Rong-Hao; Hua, Chi-Chung; Lin, Po-Chang; Wang, Ting-Yu; Chen, Show-An

    2016-07-20

    The mesoscale aggregation properties of C60 in two distinct aromatic solvents (toluene and chlorobenzene) and a practical range of concentrations (c = 1-2 and c = 1-5 mg mL(-1), respectively) were systematically explored by static/dynamic light scattering (SLS/DLS), small angle X-ray scattering (SAXS), depolarized dynamic light scattering (DDLS), and cryogenic transmission electron microscopy (cryo-TEM) analyses. The central observations were as follows: (1) aggregate species of sizes in the range of several hundred nanometers have been independently revealed by SLS, DLS, and DDLS analyses for both solvent systems. (2) DDLS and cryo-TEM measurements further revealed that while C60 clusters are notably anisotropic (rod-like) in chlorobenzene, they are basically isotropic (spherical) in toluene. (3) Detailed analyses of combined SLS and SAXS profiles suggested that varied, yet self-similar, solvent-induced aggregate units were responsible for the distinct (mesoscale) aggregation features noted above. (4) From a dynamic perspective, specially commissioned DLS measurements ubiquitously displayed two relaxation modes (fast and slow mode), with the second (slow) mode being q (wave vector) independent. While the fast mode in both solvent systems was basically diffusive by nature and leads to geometrical features in good agreement with the above static analyses, the slow mode was analyzed and tentatively suggested to reflect the effect of mutual confinement. (5) Micron-scale aggregate morphology of drop-cast thin films displays similar contrasting features for the two solvent media used. Overall, this study suggests that solvent-induced, nanoscale, aggregate units may be a promising factor to control a hierarchy of microscopic aggregation properties of C60 solutions and thin films. PMID:27376417

  10. Biotransformation of nitrobenzene by bacteria containing toluene degradative pathways.

    PubMed Central

    Haigler, B E; Spain, J C

    1991-01-01

    Nonpolar nitroaromatic compounds have been considered resistant to attack by oxygenases because of the electron withdrawing properties of the nitro group. We have investigated the ability of seven bacterial strains containing toluene degradative pathways to oxidize nitrobenzene. Cultures were induced with toluene vapor prior to incubation with nitrobenzene, and products were identified by high-performance liquid chromatography and gas chromatography-mass spectrometry. Pseudomonas cepacia G4 and a strain of Pseudomonas harboring the TOL plasmid (pTN2) did not transform nitrobenzene. Cells of Pseudomonas putida F1 and Pseudomonas sp. strain JS150 converted nitrobenzene to 3-nitrocatechol. Transformation of nitrobenzene in the presence of 18O2 indicated that the reaction in JS150 involved the incorporation of both atoms of oxygen in the 3-nitrocatechol, which suggests a dioxygenase mechanism. P. putida 39/D, a mutant strain of P. putida F1, converted nitrobenzene to a compound tentatively identified as cis-1,2-dihydroxy-3-nitrocyclohexa-3,5-diene. This compound was rapidly converted to 3-nitrocatechol by cells of strain JS150. Cultures of Pseudomonas mendocina KR-1 converted nitrobenzene to a mixture of 3- and 4-nitrophenol (10 and 63%, respectively). Pseudomonas pickettii PKO1 converted nitrobenzene to 3- and 4-nitrocatechol via 3- and 4-nitrophenol. The nitrocatechols were slowly degraded to unidentified metabolites. Nitrobenzene did not serve as an inducer for the enzymes that catalyzed its oxidation. These results indicate that the nitrobenzene ring is subject to initial attack by both mono- and dioxygenase enzymes. PMID:1781679

  11. An investigation of hormesis of trichloroethylene in L-02 liver cells by differential proteomic analysis.

    PubMed

    Huang, Hai-Yan; Liu, Jian-Jun; Xi, Ren-Rong; Xing, Xiu-Mei; Yuan, Jian-Hui; Yang, Lin-Qing; Tao, Gong-Hua; Gong, Chun-Mei; Zhuang, Zhi-Xiong

    2009-11-01

    Hormesis is the dose-response pattern of the biological responses to toxic chemicals, characterized by low-dose stimulation and high-dose inhibition. Although it is known that some cell types exhibit an adaptive response to low levels of cytotoxic agents, its molecular mechanism is still unclear and it has yet to be established whether this is a universal phenomenon that occurs in all cell types in response to exposure to every chemical. Trichloroethylene (TCE) is an organic solvent widely used and is released into the atmosphere from industrial degreasing operations. Acute (short-term) and chronic (long-term) inhalation exposure to trichloroethylene can affect the human health. In order to elucidate a cell-survival adaptive response of L-02 liver cells exposed to low dose of TCE, CCK-8 assay was used to assess cytotoxicity, and examined the possible mechanisms of hormesis by proteomics technology. We found that exposure of L-02 liver cells to low level of TCE resulted in adaptation to further exposure to higher level, about 1,000 protein-spots were obtained by two-dimensional electrophoresis (2-DE) and five protein spots were identified by matrix-assisted laser desorption/ionization mass spectrometry and tandem mass spectrometry sequencing of tryptic peptides. Our results suggest that a relationship may exist between identified proteins and TCE-induced hormesis, which are very useful for further study of the mechanism and risk assessment of TCE. PMID:19109764

  12. Enhanced dechlorination of trichloroethylene using electrospun polymer nanofibrous mats immobilized with iron/palladium bimetallic nanoparticles.

    PubMed

    Ma, Hui; Huang, Yunpeng; Shen, Mingwu; Guo, Rui; Cao, Xueyan; Shi, Xiangyang

    2012-04-15

    Fe/Pd bimetallic nanoparticles (NPs) have held great promise for treating trichloroethylene (TCE)-contaminated groundwater, without the accumulation of chlorinated intermediates. However, the conventionally used colloidal Fe/Pd NPs usually aggregate rapidly, resulting in a reduced reactivity. To reduce the particle aggregation, we employed electrospun polyacrylic acid (PAA)/polyvinyl alcohol (PVA) polymer nanofibers as a nanoreactor to immobilize Fe/Pd bimetallic NPs. In the study, the water-stable PAA/PVA nanofibrous mats were complexed with Fe (III) ions via the binding with the free carboxyl groups of PAA for subsequent formation and immobilization of zero-valent iron (ZVI) NPs. Fe/Pd bimetallic NPs were then formed by the partial reduction of Pd(II) ions with ZVI NPs. The formed electrospun nanofibrous mats containing Fe/Pd bimetallic NPs with a diameter of 2.8 nm were characterized by scanning electron microscopy, energy-dispersive spectroscopy, transmission electron microscopy, thermogravimetric analysis, and inductively coupled plasma-atomic emission spectroscopy. The Fe/Pd NP-containing electrospun PAA/PVA nanofibrous mats exhibited higher reactivity than that of the ZVI NP-containing mats or colloidal Fe/Pd NPs in the dechlorination of trichloroethylene (TCE), which was used as a model contaminant. With the high surface area to volume ratio, high porosity, and great reusability of the fibrous mats immobilized with the bimetallic NPs, the composite nanofibrous mats should be amenable for applications in remediation of various environmental contaminants. PMID:22138171

  13. Performance of genetic risk factors in prediction of trichloroethylene induced hypersensitivity syndrome

    PubMed Central

    Dai, Yufei; Chen, Ying; Huang, Hanlin; Zhou, Wei; Niu, Yong; Zhang, Mingrong; Bin, Ping; Dong, Haiyan; Jia, Qiang; Huang, Jianxun; Yi, Juan; Liao, Qijun; Li, Haishan; Teng, Yanxia; Zang, Dan; Zhai, Qingfeng; Duan, Huawei; Shen, Juan; He, Jiaxi; Meng, Tao; Sha, Yan; Shen, Meili; Ye, Meng; Jia, Xiaowei; Xiang, Yingping; Huang, Huiping; Wu, Qifeng; Shi, Mingming; Huang, Xianqing; Yang, Huanming; Luo, Longhai; Li, Sai; Li, Lin; Zhao, Jinyang; Li, Laiyu; Wang, Jun; Zheng, Yuxin

    2015-01-01

    Trichloroethylene induced hypersensitivity syndrome is dose-independent and potentially life threatening disease, which has become one of the serious occupational health issues and requires intensive treatment. To discover the genetic risk factors and evaluate the performance of risk prediction model for the disease, we conducted genomewide association study and replication study with total of 174 cases and 1761 trichloroethylene-tolerant controls. Fifty seven SNPs that exceeded the threshold for genome-wide significance (P < 5 × 10−8) were screened to relate with the disease, among which two independent SNPs were identified, that is rs2857281 at MICA (odds ratio, 11.92; Pmeta = 1.33 × 10−37) and rs2523557 between HLA-B and MICA (odds ratio, 7.33; Pmeta = 8.79 × 10−35). The genetic risk score with these two SNPs explains at least 20.9% of the disease variance and up to 32.5-fold variation in inter-individual risk. Combining of two SNPs as predictors for the disease would have accuracy of 80.73%, the area under receiver operator characteristic curves (AUC) scores was 0.82 with sensitivity of 74% and specificity of 85%, which was considered to have excellent discrimination for the disease, and could be considered for translational application for screening employees before exposure. PMID:26190474

  14. Reductive dehalogenation of trichloroethylene with zero-valent iron: Surface profiling microscopy and rate enhancement studies

    SciTech Connect

    Gotpagar, J.; Lyuksyutov, S.; Cohn, R.; Grulke, E.; Bhattacharyya, D.

    1999-11-23

    Mechanistic aspects of the reductive dehalogenation of trichloroethylene using zerovalent iron are studied with three different surface characterization techniques. These include scanning electron microscopy, surface profilometry, and atomic force microscopy. It was found that the pretreatment of an iron surface by chloride ions causes enhancement in the initial degradation rates. This enhancement was attributed to the increased roughness of the iron surface due to crevice corrosion obtained by pretreatment. The results indicate that the fractional active site concentration for the reactive sorption of trichloroethylene is related to the number of defects/abnormalities present on the surface of the iron. This was elucidated with the help of atomic force microscopy. Two possible mechanisms include (1) a direct hydrogenation in the presence of defects acting as catalyst and (2) an enhancement due to the two electrochemical cells operating in proximity to each other. The result of this study has potential for further research to achieve an increase in the reaction rates by surface modifications in a practical scenario.

  15. Quantitative evaluation of pathways involved in trichloroethylene reduction by zero-valent metals: Iron and zinc

    SciTech Connect

    Arnold, W.; Roberts, A.L.; Burris, D.R.; Campbell, T.J.

    1995-12-31

    In order to design in situ remediation systems using zero-valent metals, the mechanism and kinetics of chlorinated solvent degradation by zero-valent metals need clarification. These issues are addressed by conducting detailed investigations of the pathways involved in trichloroethylene (TCE) reduction by two zero-valent metals. Analyses are based on batch reaction data for chloroethylene reduction by iron and zinc. Experiments were conducted using TCE and each readily available reaction product of TCE degradation as a starting material and monitoring the disappearance of the parent chemical and the appearance of reaction products over time. Models were developed by working backwards through the hypothesized reaction sequence. Determining rate constants for the latter steps in the pathway, inserting them into the more complex models for more highly oxidized compounds, and obtaining rate constants for the remaining steps in the transformation of the oxidized species was repeated until a model for trichloroethylene was developed. Results indicate that reactions may not occur via a process of sequential hydrogenolysis or hydrogenation. Ethylene and/or ethane production are too rapid to be accounted for in this manner. The product distribution, especially the presence of acetylene, can only be explained by invoking reductive elimination reactions.

  16. Effects of trichloroethylene and perchloroethylene on wild rodents at Edwards Air Force Base, California, USA

    USGS Publications Warehouse

    Spring, S.E.; Miles, A.K.; Anderson, M.J.

    2004-01-01

    Effects of inhalation of volatilized trichloroethylene (TCE) or perchloroethylene (PCE) were assessed based on the health and population size of wild, burrowing mammals at Edwards Air Force Base (CA, USA). Organic soil-vapor concentrations were measured at three sites with aquifer contamination of TCE or PCE of 5.5 to 77 mg/L and at two uncontaminated reference sites. Population estimates of kangaroo rats (Dipodomys merriami and D. panamintinus) as well as hematology, blood chemistry, and histopathology of kangaroo rats and deer mice (Peromyscus maniculatus) were compared between contaminated and uncontaminated populations. Maximum soil-gas concentrations associated with groundwater contamination were less than 1.5 ??l/L of TCE and 0.07 ??l/L of PCE. Population estimates of kangaroo rats were similar at contaminated and reference sites. Hematology, blood chemistry, and histopathology of kangaroo rats and deer mice indicated no evidence of health effects caused by exposure. Trichloroethylene or PCE in groundwater and in related soil gas did not appear to reduce the size of small mammal populations or impair the health of individuals.

  17. Effects of trichloroethylene and perchloroethylene on wild rodents at Edwards Air Force Base, California, USA.

    PubMed

    Spring, Sarah E; Miles, A Keith; Anderson, Michael J

    2004-09-01

    Effects of inhalation of volatilized trichloroethylene (TCE) or perchloroethylene (PCE) were assessed based on the health and population size of wild, burrowing mammals at Edwards Air Force Base (CA, USA). Organic soil-vapor concentrations were measured at three sites with aquifer contamination of TCE or PCE of 5.5 to 77 mg/L and at two uncontaminated reference sites. Population estimates of kangaroo rats (Dipodomys merriami and D. panamintinus) as well as hematology, blood chemistry, and histopathology of kangaroo rats and deer mice (Peromyscus maniculatus) were compared between contaminated and uncontaminated populations. Maximum soil-gas concentrations associated with groundwater contamination were less than 1.5 microl/L of TCE and 0.07 microl/L of PCE. Population estimates of kangaroo rats were similar at contaminated and reference sites. Hematology, blood chemistry, and histopathology of kangaroo rats and deer mice indicated no evidence of health effects caused by exposure. Trichloroethylene or PCE in groundwater and in related soil gas did not appear to reduce the size of small mammal populations or impair the health of individuals. PMID:15378993

  18. Performance characterization of a model bioreactor for the biodegradation of trichloroethylene by 'pseudomonas cepacia' g4

    SciTech Connect

    Folsom, B.R.; Chapman, P.J.

    1991-01-01

    Of the volatile organic chemicals present in common groundwater contaminants, trichloroethylene (TCE) is the one most commonly found. TCE has been shown to be biodegraded by axenic cultures of aerobic organisms. Pseudomonas cepacia G4 grown in chemostats with phenol demonstrated constant specific degradation rates for both phenol and trichloroethylene (TCE) over a range of dilution rates. Washout of cells from chemostats was evident at a dilution rate of 0.2/h at 28C. Increased phenol concentrations in the nutrient feed led to increased biomass production with constant specific degradation rates for both phenol and TCE. The addition of lactate to the phenol feed led to increased biomass production but lowered specific phenol and TCE degradation rates. The maximum potential for TCE degradation was about 1.1 g per day per g of cell protein. Cell growth and degradation kinetic parameters were used in the design of a recirculating bioreactor for TCE degradation. In the reactor, the total amount of TCE degraded increased as either reaction time or biomass was increased. TCE degradation was observed up to 300 microM TCE with no significant decreases in rates. On the average, the reactor was able to degrade 0.7 g of TCE per day per g of cell protein. The results demonstrate the feasibility of TCE bioremediation through the use of bioreactors. (Copyright (c) 1991, American Society for Microbiology.)

  19. Characterization of an inhaled toluene drug discrimination in mice: effect of exposure conditions and route of administration

    PubMed Central

    Shelton, Keith L.; Slavova-Hernandez, Galina

    2009-01-01

    The drug discrimination procedure in animals has been extensively utilized to model the abuse related, subjective effects of drugs in humans, but it has seldom been used to examine abused volatile inhalants like toluene. The present study sought to characterize the temporal aspects of toluene's discriminative stimulus as well assess toluene blood concentrations under identical exposure conditions. B6SJLF1/J mice were trained to discriminate 10 min of exposure to 6000 ppm inhaled toluene vapor from air. Toluene vapor concentration dependently substituted for the training exposure condition with longer exposures to equivalent concentrations producing greater substitution than shorter exposures. Toluene's discriminative stimulus effects dissipated completely by 60 min after the cessation of exposure. Injected liquid toluene dose-dependently substituted for toluene vapor as well as augmenting the discriminative stimulus effects of inhaled toluene. Toluene blood concentrations measured under several exposure conditions which produced full substitution were all nearly identical suggesting that the concentration of toluene in the animals tissues at the time of testing determined discriminative performance. These results indicate that the discriminative stimulus effects of inhaled toluene vapor are likely mediated by CNS effects rather than by it's pronounced peripheral stimulus effects. PMID:19268500

  20. Microbial degradation of toluene under sulfate-reducing conditions and the influence of iron on the process.

    PubMed Central

    Beller, H R; Grbić-Galić, D; Reinhard, M

    1992-01-01

    Toluene degradation occurred concomitantly with sulfate reduction in anaerobic microcosms inoculated with contaminated subsurface soil from an aviation fuel storage facility near the Patuxent River (Md.). Similar results were obtained for enrichment cultures in which toluene was the sole carbon source. Several lines of evidence suggest that toluene degradation was directly coupled to sulfate reduction in Patuxent River microcosms and enrichment cultures: (i) the two processes were synchronous and highly correlated, (ii) the observed stoichiometric ratios of moles of sulfate consumed per mole of toluene consumed were consistent with the theoretical ratio for the oxidation of toluene to CO2 coupled with the reduction of sulfate to hydrogen sulfide, and (iii) toluene degradation ceased when sulfate was depleted, and conversely, sulfate reduction ceased when toluene was depleted. Mineralization of toluene was confirmed in experiments with [ring-U-14C]toluene. The addition of millimolar concentrations of amorphous Fe(OH)3 to Patuxent River microcosms and enrichment cultures either greatly facilitated the onset of toluene degradation or accelerated the rate once degradation had begun. In iron-amended microcosms and enrichment cultures, ferric iron reduction proceeded concurrently with toluene degradation and sulfate reduction. Stoichiometric data and other observations indicate that ferric iron reduction was not directly coupled to toluene oxidation but was a secondary, presumably abiotic, reaction between ferric iron and biogenic hydrogen sulfide. PMID:1575481

  1. Microbial degradation of toluene under sulfate-reducing conditions and the influence of iron on the process

    SciTech Connect

    Beller, H.R.; Grbic-Galic, D.; Reinhard, M.

    1992-01-01

    Toluene degradation occurred concomitantly with sulfate reduction in anaerobic microcosms inoculated with contaminated subsurface soil from an aviation fuel storage facility near the Patuxent River (Md.). Similar results were obtained from enrichment cultures in which toluene was the sole carbon source. Several lines of evidence suggest that toluene degradation was directly coupled to sulfate reduction in Patuxent River microcosms and enrichment cultures: (1) the two processes were synchronous and highly correlated, (2) the observed stoichiometric ratios of moles of sulfate consumed per mole of toluene consumed were consistent with the theoretical ratio for the oxidation of toluene to CO2 coupled with the reduction of sulfate to hydrogen sulfide, and (3) toluene degradation ceased when sulfate was depleted, and conversely, sulfate reduction ceased when toluene was depleted. Mineralization of toluene was confirmed in experiments with (ring-U-14C)toluene. The addition of millimolar concentrations of amorphous Fe(OH)3 to Patuxent River microcosms and enrichment cultures either greatly facilitated the onset of toluene degradation or accelerated the rate once degradation had begun. In iron-amended microcosms and enrichment cultures, ferric iron reduction proceeded concurrently with toluene degradation and sulfate reduction. Stoichiometric data and other observations indicate that ferric iron reduction was not directly coupled to toluene oxidation but was a secondary, presumably abiotic, reaction between ferric iron and biogenic hydrogen sulfide. (Copyright (c) 1992, American Society for Microbiology.)

  2. Evaluation of the Potential Impact of Inhibition of Trichloroethylene Metabolism in the Liver on Extra-Hepatic Toxicity

    EPA Science Inventory

    The interaction between trichloroethylene (TCE) and chloroform (CHCI3) is less than additive, with co-exposure to TCE and CHCl3 resulting in less hepatic and renal toxicity than observed with CHCl3 alone. Vapor uptake data demonstrate that co-exposure to CHCl3 decreases the rate ...

  3. MID-FREQUENCY HEARING LOSS IN RATS FOLLOWING INHALATION EXPOSURE TO TRICHLOROETHYLENE: EVIDENCE FROM REFLEX MODIFICATION AUDIOMETRY

    EPA Science Inventory

    The present experiments were undertaken in order to characterize the hearing loss associated with 1,1,2-trichloroethylene (TCE) exposure. dult male LE rats were exposed to TCE via inhalation (whole body) for 6hr/day for 5 days. he concentration-effect function (0-4000 ppm) was de...

  4. COUNTER-DIFFUSION OF ISOTOPICALLY LABELED TRICHLOROETHYLENE IN SILICA GEL AND GEOSORBENT MICROPORES: COLUMN RESULTS. (R822626)

    EPA Science Inventory

    To investigate counter-diffusion in microporous sorbents, the rate of
    exchange between deuterated trichloroethylene (DTCE) in fast desorbing sites and
    nondeuterated TCE (1HTCE) in slow desorbing sites was measured.
    Exchange rates were measured for a sili...

  5. Removal of Trichloroethylene by Activated Carbon in the Presence and Absence of TiO2 Nanoparticles

    EPA Science Inventory

    Nanoparticles (NPs) are emerging as a new type of contaminant in water and wastewater. The fate of titanium dioxide nanoparticles (TiO2NPs) in a granular activated carbon (GAC) adsorber and their impact on the removal of trichloroethylene (TCE) by GAC was investigated...

  6. USE OF CARBON STABLE ISOTOPE FOR THE DECHLORINATION OF TRICHLOROETHYLENE ON GRANULAR-GRAPHITE PACKED ELECTRODES (PRESENTATION)

    EPA Science Inventory

    Trichloroethylene (TCE) is widely used as a solvent in metal processing and electronic manufacturing industries, but waste and spilled TCE often results in blocks of non-aqueous liquid in vadose and saturated zones which become continuous contamination sources for groundwater. El...

  7. MICROCOSM AND IN-SITU FIELD STUDIES OF ENHANCED BIOTRANSFORMATION OF TRICHLOROETHYLENE BY PHENOL-UTILIZING MICROORGANISMS

    EPA Science Inventory

    The ability of different aerobic groundwater microorganisms to cometabolically degrade trichloroethylene (TCE), 1,2-cis-dichloroethylene (c-DCE), and 1,2-trans-dichloroethylene (t-DCE) was evaluated both in groundwater-fed microcosms and in situ in a shallow aquifer. Microcosms a...

  8. Fifteen-year Assessment of a Permeable Reactive Barrier for Treatment of Chromate and Trichloroethylene in Groundwater

    EPA Science Inventory

    The fifteen-year performance of a granular iron, permeable reactive barrier (PRB; Elizabeth City, North Carolina) is reviewed with respect to contaminant treatment (hexavalent chromium and trichloroethylene) and hydraulic performance. Due to in-situ treatment of the chromium sou...

  9. [Mechanism and performance of a membrane bioreactor for treatment of toluene vapors].

    PubMed

    Ye, Qi-hong; Wei, Zai-shan; Xiao, Pan; Li, Hua-qin; Zhang, Zai-li; Fan, Qin-juan

    2012-08-01

    The performance of a membrane bioreactor for treatment of toluene as a model pollutant is presented. Effects of toluene inlet concentration, residence time, spray density and pH of liquid phase on the toluene removal rate were evaluated. The experimental results showed that the toluene removal efficiency reached 99%. The optimal pH, residence time and spray density were 7.2, 6.4 s and 2.5 m3 x (m2 x h)(-1), respectively. The gas-phase biodegradation intermediate products were acetaldehyde acid (C2H2O3) and vinyl formic acid (C3H4O2), which were identified by means of gas chromatography/mass spectrometry (GC/MS). The mechanism of toluene degradation using a membrane bioreactor can be described as the combination of mass transfer from hollow fiber membrane to biofilm and biological degradation. Toluene (C6H5CH3) and oxygen diffused from the gas phase to the wet layer of the biofilm and were then consumed by the microbial communities. Toluene was oxidized to the intermediate organic products such as acetaldehyde acid (C2H2O3) and vinyl formic acid (C3H4O2), and the intermediate products were then converted to CO2 and H2O through continuous biological oxidation reactions. PMID:23213872

  10. Biodegradation of toluene vapor in coir based upflow packed bed reactor by Trichoderma asperellum isolate.

    PubMed

    Gopinath, M; Mohanapriya, C; Sivakumar, K; Baskar, G; Muthukumaran, C; Dhanasekar, R

    2016-03-01

    In the present study, a new biofiltration system involving a selective microbial strain isolated from aerated municipal sewage water attached with coir as packing material was developed for toluene degradation. The selected fungal isolate was identified as Trichoderma asperellum by 16S ribosomal RNA (16S rRNA) sequencing method, and pylogenetic tree was constructed using BLASTn search. Effect of various factors on growth and toluene degradation by newly isolated T. asperellum was studied in batch studies, and the optimum conditions were found to be pH 7.0, temperature 30 °C, and initial toluene concentration 1.5 (v/v)%. Continuous removal of gaseous toluene was monitored in upflow packed bed reactor (UFPBR) using T. asperellum. Effect of various parameters like column height, flow rate, and the inlet toluene concentration were studied to evaluate the performance of the biofilter. The maximum elimination capacity (257 g m(-3) h(-1)) was obtained with the packing height of 100 cm with the empty bed residence time of 5 min. Under these optimum conditions, the T. asperellum showed better toluene removal efficiency. Kinetic models have been developed for toluene degradation by T. asperellum using macrokinetic approach of the plug flow model incorporated with Monod model. PMID:25903193

  11. Two New Mycobacterium Strains and Their Role in Toluene Degradation in a Contaminated Stream

    PubMed Central

    Tay, Stephen T.-L.; Hemond, Harold F.; Polz, Martin F.; Cavanaugh, Colleen M.; Dejesus, Indhira; Krumholz, Lee R.

    1998-01-01

    Two toluene-degrading strains, T103 and T104, were isolated from rock surface biomass in a freshwater stream contaminated with toluene. The strains exhibit different capacities for degradation of toluene and other aromatic compounds and have characteristics of the genus Mycobacterium. Both are aerobic, rod-shaped, gram-positive, nonmotile, and acid-alcohol fast and produce yellow pigments. They have mainly straight-chain saturated and monounsaturated fatty acids with 10 to 20 carbon atoms and large amounts of tuberculostearic acid that are typical of mycobacteria. Fatty acid analyses indicate that T103 and T104 are different mycobacterial strains that are related at the subspecies level. Their identical 16S rDNA sequences are most similar to Mycobacterium aurum and Mycobacterium komossense, and they constitute a new species of fast-growing mycobacteria. Ecological studies reveal that toluene contamination has enriched for toluene-degrading bacteria in the epilithic microbial community. Strains T103 and T104 play only a small role in toluene degradation in the stream, although they are present in the habitat and can degrade toluene. Other microorganisms are consequently implicated in the biodegradation. PMID:9572941

  12. Maternal and Fetal Blood and Organ Toluene Levels in Rats Following Acute and Repeated Binge Inhalation Exposure

    PubMed Central

    Bowen, Scott E.; Hannigan, John H.; Irtenkauf, Susan

    2007-01-01

    Inhalation of organic solvents is a persistent form of drug abuse with particular concern being the abuse of inhalants by women of child-bearing age. While studies have begun assessing postnatal outcomes of offspring exposed prenatally to inhalants, relatively little is known about the distribution of toluene in blood and body tissues of pregnant, inhalant-abusing women, or in the fetuses. The present study assessed the tissue toluene levels attained following brief toluene exposures using a pre-clinical rat model of maternal inhalant abuse. Timed-pregnant Sprague-Dawley rats were exposed to toluene at 8,000 or 12,000 parts per million (ppm) for 15, 30 or 45 min/exposure. Exposures occurred twice each day from gestational day 8 (GD8) through GD20. Immediately following the second exposure on GD8, GD14 and GD20 blood was taken from the saphenous vein of the dams. Following saphenous vein blood collection on GD20, dams were sacrificed and trunk blood was collected along with maternal tissue specimens from cerebellum, heart, lung, kidney and liver. The placenta, amniotic fluid and fetal brain were also collected. Results demonstrated that maternal saphenous blood toluene levels increased as the inhaled concentration of toluene and duration of exposure increased. The maternal cerebellum, heart, kidney and liver appeared to be saturated after 30 min on GD20 such that toluene levels in those organs were equivalent across all ambient concentrations of inhaled toluene. Toluene levels also increased in fetal brain as the inhaled concentration of toluene increased and in placenta and amniotic fluid as the duration of exposure increased. Toluene levels in all tissues at GD20, except maternal lung and amniotic fluid, were higher than in maternal saphenous blood suggesting that toluene concentrated in those organs. Measurement of toluene levels in blood and other tissues following repeated toluene exposure demonstrated that toluene readily reaches a variety of potential sites

  13. Sarcosine attenuates toluene-induced motor incoordination, memory impairment, and hypothermia but not brain stimulation reward enhancement in mice

    SciTech Connect

    Chan, Ming-Huan; Chung, Shiang-Sheng; Stoker, Astrid K.; Markou, Athina; Chen, Hwei-Hsien

    2012-12-01

    Toluene, a widely used and commonly abused organic solvent, produces various behavioral disturbances, including motor incoordination and cognitive impairment. Toluene alters the function of a large number of receptors and ion channels. Blockade of N-methyl-D-aspartate (NMDA) receptors has been suggested to play a critical role in toluene-induced behavioral manifestations. The present study determined the effects of various toluene doses on motor coordination, recognition memory, body temperature, and intracranial self-stimulation (ICSS) thresholds in mice. Additionally, the effects of sarcosine on the behavioral and physiological effects induced by toluene were evaluated. Sarcosine may reverse toluene-induced behavioral manifestations by acting as an NMDA receptor co-agonist and by inhibiting the effects of the type I glycine transporter (GlyT1). Mice were treated with toluene alone or combined with sarcosine pretreatment and assessed for rotarod performance, object recognition memory, rectal temperature, and ICSS thresholds. Toluene dose-dependently induced motor incoordination, recognition memory impairment, and hypothermia and lowered ICSS thresholds. Sarcosine pretreatment reversed toluene-induced changes in rotarod performance, novel object recognition, and rectal temperature but not ICSS thresholds. These findings suggest that the sarcosine-induced potentiation of NMDA receptors may reverse motor incoordination, memory impairment, and hypothermia but not the enhancement of brain stimulation reward function associated with toluene exposure. Sarcosine may be a promising compound to prevent acute toluene intoxications by occupational or intentional exposure. -- Highlights: ► Toluene induces impairments in Rotarod test and novel object recognition test. ► Toluene lowers rectal temperature and ICSS thresholds in mice. ► Sarcosine reverses toluene-induced changes in motor, memory and body temperature. ► Sarcosine pretreatment does not affect toluene

  14. Measurement of toluene bioconversion during ventilation in a bench-scale soil column

    SciTech Connect

    Malina, G.; Grotenhuis, T.; Cuypers, C.; Rulkens, W.

    1995-12-31

    The ratio between ventilation and biodegradation of toluene in the vadose zone during bioventing was studied by bench-scale soil column experiments, using gas chromatography headspace analysis. Biodegradation batch tests showed that toluene vapor concentrations above 75% of the saturation concentration completely retarded the bioconversion rate. To determine the role of bioconversion and physical removal of toluene from soil, CO{sub 2}-free air and N{sub 2} were used, respectively, as flushing gases, with a flowrate of 1.0 L/h or 39.5 cm{sup 3}/(cm{sup 2}{center_dot}h). In a column with ca. 4 kg of sandy soil, at a water content of 15% w/w, i.e., 75% of field capacity , and temperature 20 C, the initial concentration of toluene, 4,000 mg/kg, was reduced within 11 days to between 0.5 and 0.2 mg/kg during bioventing, and to between 60 and 70 mg/kg when bioconversion was not involved. Soil extraction after 24 days of venting showed a residual toluene concentration of 1.4 mg/kg. Mass balance analysis of toluene and CO{sub 2} indicated that about 90% of toluene was evaporated and 10% was biodegraded. Time constants for volatilization and bioconversion were comparable at the flowrate applied. These results enable determination of the optimum airflow for venting and oxygen supply required for toluene biodegradation, and design of an optimum bioventing strategy for toluene removal.

  15. Binge toluene exposure in pregnancy and pre-weaning developmental consequences in rats.

    PubMed

    Bowen, Scott E; Hannigan, John H

    2013-01-01

    Binge Toluene Exposure in Pregnancy and Pre-weaning Developmental Consequences in Rats. Bowen, S.E. and Hannigan, J.H. The persistent rate of abuse of inhaled organic solvents, especially among women of child-bearing age, raises the risk for teratogenic effects of maternal toluene abuse. In this study, timed-pregnant Sprague Dawley rats were exposed from Gestation Day (GD) 8 to GD20 to 12,000 or 8000 parts per million (ppm) toluene, or 0ppm (controls) for 30min twice daily, 60min total daily exposure. Pups were assessed from postnatal day (PN) 4 to PN21 using a developmental battery measuring growth (i.e., body weight), maturational milestones (e.g., eye opening & incisor eruption), and biobehavioral development (e.g., negative geotaxis & surface righting). Pups exposed in utero to 12,000ppm or 8000ppm toluene weighed significantly less than the non-exposed control pups beginning at PN4 and PN12 (respectively) until PN21. Toluene resulted in significant increases in an index of poor perinatal outcome, specifically a composite of malformations, defined "runting" and neonatal death. No significant delays were observed in reaching maturational milestones. The results reveal that brief, repeated, prenatal exposure to high concentrations of toluene can cause growth retardation and malformations in rats. A comparison of the present, conservative results with findings in previous studies implies that binge patterns of toluene exposure in pregnant rats modeling human solvent abuse can result in developmental and morphological deficits in offspring. These results do not exclude the possibility that maternal toxicity as well as teratogenic effects of toluene may contribute to outcomes. The results suggest that abuse of inhaled organic solvents like toluene may result in similar early developmental outcomes in humans. PMID:23597557

  16. Acetate enhances the specific consumption rate of toluene under denitrifying conditions.

    PubMed

    Martínez-Hernández, Sergio; Olguín, Eugenia J; Gómez, Jorge; Cuervo-López, Flor de María

    2009-11-01

    Toluene is usually present in the environment as a contaminant along with other carbon sources which may influence its removal. In this work we studied the effect of a readily consumable carbon source such as acetate on toluene mineralization under denitrifying conditions. Continuous and batch cultures with stabilized denitrifying sludge were carried out. An upflow anaerobic sludge blanket reactor (UASB) was fed with several ratios of acetate-C/toluene-C loading rates (mg C/L-day: 100/0, 75/25, 50/50, and 0/100). Batch assays with different acetate-C/toluene-C ratios (10/70, 30/50, 50/30, and 65/20 mg C/L) were also done. As the acetate loading rate decreased in the culture, the carbon and nitrate consumption efficiency decreased by 40% and 34%, respectively. HCO(3) (-) and N(2) yields also decreased by 43%. Analysis of the denitrifying community using the denaturing gradient gel electrophoresis technique indicated that there was no clear relationship between its population profile and the metabolic pattern. In batch assays, when the acetate concentration was higher than that of toluene (65 mg acetate-C/L vs 20 mg toluene-C/L), the specific consumption rate of toluene (q(T)) was two times higher than in assays with 20 mg toluene-C/L as the sole electron source (0.006 mg C/mg volatile suspended solids-day). It is proposed that acetate can act by enhancing the growth of microbial populations and as a biochemical enhancer. The results show that acetate addition can be useful to improve the consumption rate of toluene in contaminated water. PMID:19387525

  17. NBDT (3-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-3-toluene)--a novel fluorescent dye for studying mechanisms of toluene uptake into vital bacteria.

    PubMed

    Sträuber, H; Hübschmann, T; Jehmlich, N; Schmidt, F; von Bergen, M; Harms, H; Müller, S

    2010-02-01

    Uptake of small hydrophobic substances such as toluene into bacteria is widely assumed to occur by passive diffusion. Some toluene degrading bacteria, however, are described to contain uptake systems which may be involved in the transport of this compound. In this study, a fluorescently labeled toluene analogue dye (3-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-3-toluene; NBDT), flow cytometry, and shot gun proteome analysis were used to follow toluene uptake into bacteria in more detail. The new dye has excitation peaks at 444 and 475 nm and an emission peak at 537 nm. The toluene-degraders P. putida mt-2 and P. putida F1 as well as P. putida KT2440 and E. coli K12 as negative controls were included. To enable quantification of NBDT uptake, carbonyl cyanide 3-chlorophenylhydrazone (CCCP) was added to inactivate NBDT efflux pumps. The porin inhibitor cadaverine was added to study the porin-mediated influx of toluene. Cadaverine reduced NBDT uptake by toluene-grown P. putida mt-2 and F1 by 25% and 42%, respectively, thus revealing an involvement and possibly a regulatory function of porins in the uptake of the toxic substrate toluene. Shot gun proteome measurements gave evidence for the presence of toluene transporting porins in P. putida mt-2 grown on toluene but not when grown on glucose. PMID:19821519

  18. Inhaled toluene produces pentobarbital-like discriminative stimulus effects in mice

    SciTech Connect

    Rees, D.C.; Coggeshall, E.; Balster, R.L.

    1985-10-07

    The abuse of volatile solvents may be due to their ability to produce an intoxication similar to that produced by classical central nervous system depressants such as the barbiturates and ethanol. To evaluate this hypothesis, mice were trained to discriminate pentobarbital from saline injections in a two-lever operant task. Stimulus generalization was examined following 20-min inhalation exposures to toluene (300-5400 ppm). In 8 of 10 subjects, pentobarbital-lever responding occurred following toluene exposure indicating an overlap in the discriminative stimulus properties of toluene and pentobarbital.

  19. Interfacial properties of asphaltenes at toluene-water interfaces.

    PubMed

    Zarkar, Sharli; Pauchard, Vincent; Farooq, Umer; Couzis, Alexander; Banerjee, Sanjoy

    2015-05-01

    Asphaltenes are "n-alkane insoluble" species in crude oil that stabilize water-in-oil emulsions. To understand asphaltene adsorption mechanisms at oil-water interfaces and coalescence blockage, we first studied the behavior in aliphatic oil-water systems in which asphaltenes are almost insoluble. They adsorbed as monomers, giving a unique master curve relating interfacial tension (IFT) to interfacial coverage through a Langmuir equation of state (EoS). The long-time surface coverage was independent of asphaltene bulk concentration and asymptotically approached the 2-D packing limit for polydisperse disks. On coalescence, the surface coverage exceeded the 2-D limit and the asphaltene film appeared to become solidlike, apparently undergoing a transition to a soft glassy material and blocking further coalescence. However, real systems consist of mixtures of aliphatic and aromatic components in which asphaltenes may be quite soluble. To understand solubility effects, we focus here on how the increased bulk solubility of asphaltenes affects their interfacial properties in comparison to aliphatic oil-water systems. Unlike the "almost irreversible" adsorption of asphaltenes where the asymptotic interfacial coverage was independent of the bulk concentration, an equilibrium surface pressure, dependent on bulk concentration, was obtained for toluene-water systems because of adsorption being balanced by desorption. The equilibrium surface coverage could be obtained from the short- and long-term Ward-Tordai approximations. The behavior of the equilibrium surface pressure with the equilibrium surface coverage was then derived. These data for various asphaltene concentrations were used to determine the EoS, which for toluene-water could also be fitted by the Langmuir EoS with Γ∞ = 3.3 molecule/nm(2), the same value as that found for these asphaltenes in aliphatic media. Asphaltene solubility in the bulk phase only appears to affect the adsorption isotherm but not the Eo

  20. Mechanism of trichloroethylene-induced elevation of individual serum bile acids. I. Correlation of trichloroethylene concentrations to bile acids in rat serum.

    PubMed

    Hamdan, H; Stacey, N H

    1993-08-01

    The temporal relationship between trichloroethylene (TRI) and individual serum bile acids (SBA) has been investigated to gain insight into the mechanism of solvent-induced increases in SBA. Male Sprague-Dawley rats were treated with 1 mmol/kg TRI in corn oil, while control rats received only corn oil. Blood samples were collected from the abdominal aorta at 2, 4, 8, and 16 hr after dosing. Individual SBA were determined by high-performance liquid chromatography (HPLC). Liver and blood concentrations of TRI and one of its metabolites, trichloroethanol (TCEOH), were determined by gas chromatography. SBA levels reached their peak at 4 hr and returned to control levels by 16 hr. There was a relationship between SBA levels and TRI concentrations, which were also at their peak 4 hr after dosing. By 16 hr the levels were undetectable. However, peak blood concentrations of TCEOH were reached 8 hr after dosing, and remained high at 16 hr. Cholic acid and taurocholic acid showed the highest levels of bile acids. Some other bile acids were also elevated, including deoxycholic acid, taurodeoxycholic acid, ursodeoxycholic acid, chenodeoxycholic acid, and taurochenodeoxycholic acid. Determination of total bile acids in serum using an enzymatic/colorimetric method showed a similar pattern of response to that obtained with the HPLC analysis. The data are consistent with TRI having a rapid and specific effect on SBA levels by a mechanism other than liver cell damage. PMID:8346545

  1. Combination of photocatalysis downstream the non-thermal plasma reactor for oxidation of gas-phase toluene.

    PubMed

    Huang, Haibao; Ye, Daiqi

    2009-11-15

    Ozone is an undesirable byproduct of non-thermal plasma (NTP) for volatile organic compounds (VOCs) control. Photocatalysis combined downstream the NTP reactor and ozone was utilized to oxidize toluene. The multiple synergies of O(3)/UV/TiO(2) system and the mechanism of toluene decomposition were investigated. The influence factors such as energy density, humidity and UV sources were also intensively studied. The combination of photocatalysis in the post-plasma increased the conversion of toluene and ozone to almost 80 and 90%, respectively. Water vapor played a dual role in toluene destruction and ozone removal. In total, 0.75% humidity had the best conversion of toluene and ozone at these experimental conditions. The conversion of toluene enhanced with increasing ozone removal. Among the multiple oxidation processes in the O(3)/UV/TiO(2) system, the O(3)/TiO(2) process played a key role in the decomposition of toluene. PMID:19604627

  2. ESTABLISHING CHANGES IN METABOLISM OF CARBON TETRACHLORIDE IN THE PRESENCE OF TRICHLOROETHYLENE IN THE RAT THROUGH THE USE OF PHYSIOLOGICALLY BASED PHARMACOKINETIC (PBPK) MODELING

    EPA Science Inventory

    Toxicological interactions of chemicals can affect metabolism, often decreasing overall associated metabolic rates; and changes in metabolism can be evaluated through the use of mathematical models. Trichloroethylene (TCE) and carbon tetrachloride (CCl4) are common co...

  3. Suppression of Pulmonary Host Defenses and Enhanced Susceptibility to Respiratory bacterial Infection in mice Following Inhalation Exposure to Trichloroethylene and Chloroform

    EPA Science Inventory

    Numerous epidemiologic studies have associated episodes of increased air pollution with increased incidence of respiratory disease, including pneumonia, croup, and bronchitis. Trichloroethylene (TCE) and chloroform are among 33 hazardous air pollutants identified by the U.S. Env...

  4. Evaluation of the Role of Peroxisome Proliferator-Activated Receptor α (PPARα) in Mouse Liver Tumor Induction by Trichloroethylene and Metabolites

    EPA Science Inventory

    Trichloroethylene (TCE) is an industrial solvent and a widespread environmental contaminant. Induction of liver cancer in mice by TCE is thought to be mediated by two metabolites, dichloroacetate (DCA) and trichloroacetate (TCA), both of which are themselves mouse liver carcinoge...

  5. An alternate metabolic hypothesis for a binary mixture of trichloroethylene and carbon tetrachloride: application of physiologically based pharmacokinetic (PBPK) modeling in rats.

    EPA Science Inventory

    Carbon tetrachloride (CC4) and trichloroethylene (TCE) are hepatotoxic volatile organic compounds (VOCs) and environmental contaminants. Previous physiologically based pharmacokinetic (PBPK) models describe the kinetics ofindividual chemical disposition and metabolic clearance fo...

  6. Comparative Study on the Implication of Three Nanoparticles on the Removal of Trichloroethylene by Adsorption - The Pilot and Rapid Small-Scale Column Tests

    EPA Science Inventory

    The impact of three commercially-available nanoparticles (NPs) on trichloroethylene (TCE) adsorption onto granular activated carbon (GAC) was investigated. TCE Adsorption isotherm and column breakthrough experiments were conducted in the presence and absence of silicon dioxide (S...

  7. Photocatalytic decomposition of aqueous trichloroethylene and direct red-79 with TiO sub 2 as a function of irradiation indensity

    SciTech Connect

    Magrini, K.A.; Webb, J.D.

    1991-01-01

    The degradation of aqueous trichloroethylene (TCE) to CO{sub 2} and HCl is accomplished photocatalytically by irradiated TCE solutions, which contain suspensions of anatase TiO{sub 2}, which simulated sunlight.

  8. Toluene pyrolysis studies and high temperature reactions of propargyl chloride

    SciTech Connect

    Kern, R.D.; Chen, H.; Qin, Z.

    1993-12-01

    The main focus of this program is to investigate the thermal decompositions of fuels that play an important role in the pre-particle soot formation process. It has been demonstrated that the condition of maximum soot yield is established when the reaction conditions of temperature and pressure are sufficient to establish a radical pool to support the production of polyaromatic hydrocarbon species and the subsequent formation of soot particles. However, elevated temperatures result in lower soot yields which are attributed to thermolyses of aromatic ring structures and result in the bell-shaped dependence of soot yield on temperature. The authors have selected several acyclic hydrocarbons to evaluate the chemical thermodynamic and kinetic effects attendant to benzene formation. To assess the thermal stability of the aromatic ring, the authors have studied the pyrolyses of benzene, toluene, ethylbenzene, chlorobenzene and pyridine. Time-of-flight mass spectrometry (TOF) is employed to analyze the reaction zone behind reflected shock waves. Reaction time histories of the reactants, products, and intermediates are constructed and mechanisms are formulated to model the experimental data. The TOF work is often performed with use of laser schlieren densitometry (LS) to measure density gradients resulting from the heats of various reactions involved in a particular pyrolytic system. The two techniques, TOF and LS, provide independent and complementary information about ring formation and ring rupture reactions.

  9. Fatal asthma in a subject sensitized to toluene diisocyanate

    SciTech Connect

    Fabbri, L.M.; Danieli, D.; Crescioli, S.; Bevilacqua, P.; Meli, S.; Saetta, M.; Mapp, C.E.

    1988-06-01

    We report the case of a 43-yr-old car painter who died within 1 h of exposure to a polyurethane paint in the workplace. A diagnosis of asthma induced by toluene diisocyanate (TDI) had been established 6 yr before, when he underwent inhalation challenges with carbachol and with TDI. The subject had airway hyperresponsiveness to carbachol (PD20FEV1 carbachol = 0.32 mg; normal value greater than 1.0 mg) and developed an early and long-lasting asthmatic reaction after exposure to TDI in the laboratory. Although it was recommended that he change his job or stop using paints containing isocyanates, he continued to work as a car painter, taking antiasthmatic drugs both at work and at home to control asthma symptoms. On Monday, October 6, 1986, at 11:30 A. M., he developed a severe attack of asthma while he was mixing the 2 components of a polyurethane paint. Taken to hospital, he was dead on arrival. Autopsy showed no evidence of cardiac or brain disease; lungs were overinflated, the cut surface showed grey glistening mucous plugs in in the airways. Histologic examination showed denudation of airway epithelium and thickening of the basement membrane with infiltration of the lamina propria by polymorphonuclear leukocytes, mainly eosinophils, and diffuse mucous plugging of bronchioles. Bronchial smooth muscle appeared hyperplastic and disarrayed, and lung parenchyma showed focal areas of alveolar destruction adjacent to areas of perfectly intact alveolar walls.

  10. Fatal asthma in a subject sensitized to toluene diisocyanate.

    PubMed

    Fabbri, L M; Danieli, D; Crescioli, S; Bevilacqua, P; Meli, S; Saetta, M; Mapp, C E

    1988-06-01

    We report the case of a 43-yr-old car painter who died within 1 h of exposure to a polyurethane paint in the workplace. A diagnosis of asthma induced by toluene diisocyanate (TDI) had been established 6 yr before, when he underwent inhalation challenges with carbachol and with TDI. The subject had airway hyperresponsiveness to carbachol (PD20FEV1 carbachol = 0.32 mg; normal value greater than 1.0 mg) and developed an early and long-lasting asthmatic reaction after exposure to TDI in the laboratory. Although it was recommended that he change his job or stop using paints containing isocyanates, he continued to work as a car painter, taking antiasthmatic drugs both at work and at home to control asthma symptoms. On Monday, October 6, 1986, at 11:30 A. M., he developed a severe attack of asthma while he was mixing the 2 components of a polyurethane paint. Taken to hospital, he was dead on arrival. Autopsy showed no evidence of cardiac or brain disease; lungs were overinflated, the cut surface showed grey glistening mucous plugs in in the airways. Histologic examination showed denudation of airway epithelium and thickening of the basement membrane with infiltration of the lamina propria by polymorphonuclear leukocytes, mainly eosinophils, and diffuse mucous plugging of bronchioles. Bronchial smooth muscle appeared hyperplastic and disarrayed, and lung parenchyma showed focal areas of alveolar destruction adjacent to areas of perfectly intact alveolar walls.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2849334

  11. REDUCTIVE BIOTRANSFORMATION OF TETRACHLOROETHENE TO ETHENE DURING ANAEROBIC DEGRADATION OF TOLUENE: EXPERIMENTAL EVIDENCE AND KINETICS

    EPA Science Inventory

    Reductive biotransformation of tetrachloroethene (PCE) to ethene occurred during anaerobic degradation of toluene in an enrichment culture. Ethene was detected as a dominant daughter product of PCE dechlorination with negligible accumulation of other partially chlorinated ethenes...

  12. Total cross section of solid mesitylene, toluene and a mixture of them at thermal neutron energies

    NASA Astrophysics Data System (ADS)

    Rodríguez Palomino, L. A.; Cantargi, F.; Blostein, J. J.; Dawidowski, J.; Granada, J. R.

    2009-01-01

    The total neutron cross sections of mesitylene, toluene and a solution 3:2 by volume of mesitylene and toluene were measured at the electron LINAC based pulsed neutron source of Centro Atómico Bariloche. Measurements were performed at 180 K, 120 K and 31.6 K for mesitylene and at 120 K and 31.6 K for toluene and a solution 3:2 by volume of mesitylene and toluene. The systems are potential moderator materials to be considered in the design of a cold neutron source due to their high resistance to radiation and the richness in low-energy excitations of their frequency spectra, that lead to produce an enhanced cold neutron flux.

  13. TOXICITY OF AROMATIC AEROBIC BIOTRANSFORMATION PRODUCTS OF TOLUENE TO HELA CELLS

    EPA Science Inventory

    Petroleum contamination of groundwater is widely recognized as a serious environmental problem. Toluene (methylbenzene) occurs naturally in crude oil and is commonly found as a contaminant in the subsurface as a result of waste disposal and storage activities. Biological transf...

  14. Deinococcus radiodurans Engineered for Complete Toluene Degradation Facilitates Cr(VI) Reduction

    SciTech Connect

    Brim, Hassan; Osborne, Jeffrey P.; Kostandarithis, Heather M.; Fredrickson, Jim K.; Wackett, L. P.; Daly, Michael J.

    2006-08-01

    Toluene and other fuel hydrocarbons are commonly found in association with radionuclides at numerous US Department of Energy sites, frequently occurring together with Cr(VI) and other heavy metals. In this study, the extremely radiation-resistant bacterium Deinococcus radiodurans, which naturally reduces Cr(VI) to the less mobile and less toxic Cr(III), was engineered for complete toluene degradation by cloned expression of tod and xyl genes of Pseudomonas putida. The recombinant Tod/Xyl strain showed incorporation of carbon from 14C-labelled toluene into cellular macromolecules and carbon dioxide, in the absence or presence of chronic ionizing radiation. The engineered bacteria were able to oxidize toluene under both minimal and complex nutrient conditions, and recombinant cells reduced Cr(VI) in sediment microcosms. As such, the Tod/Xyl strain could provide a model for examining the reduction of metals coupled to organic contaminant oxidation in aerobic radionuclide-contaminated sediments.

  15. Oxidation of nitrotoluenes by toluene dioxygenase: Evidence for a monooxygenase reaction

    SciTech Connect

    Robertson, J.B.; Spain, J.C. ); Haddock, J.D.; Gibson, D.T. )

    1992-08-01

    Pseudomonas putida F1 and Pseudomonas sp. strain JS150 initiate toluene degradation by incorporating molecular oxygen into the aromatic nucleus to form cis-1,2-dihydroxy-3-methylcyclohexa-3,5-diene. When toluene-grown cells were incubated with 2- and 3-nitrotoluene, the major products identified were 2- and 3-nitrobenzyl alcohol, respectively. The same cells oxidized 4-nitrotoluene to 2-methyl-5-nitrophenol and 3-methyl-6-nitrocatechol. Escherichia coli JM109(pDTG601), which contains the toluene dioxygenase genes from P. putida F1 under the control of the tac promoter, oxidized the isomeric nitrotoluenes to the same metabolites as those formed by P. putida F1 and Pseudomonas sp. strain JS150. These results extend the range of substrates known to be oxidized by this versatile enzyme and demonstrate for the first time that toluene dioxygenase can oxidize an aromatic methyl substituent.

  16. ENVIRONMENTAL FACTORS AFFECTING TOLUENE DEGRADATION IN GROUND WATER AT A HAZARDOUS WASTE SITE

    EPA Science Inventory

    The microbial ecology of pristine and contaminated ground water at a chemical waste disposal site was investigated. ecently, it was determined that ground water downslope from the disposal site contained elevated levels of toxic pollutants, including benzene, toluene, xylene and ...

  17. VISUAL FUNCTION CHANGES AFTER SUBCHRONIC TOLUENE INHALATION IN LONG-EVANS RATS.

    EPA Science Inventory

    Chronic exposure to volatile organic compounds, including toluene, has been associated with visual deficits such as reduced visual contrast sensitivity or impaired color discrimination in studies of occupational or residential exposure. These reports remain controversial, howeve...

  18. Effects of long-term exposure to trichloroethylene on the behavior of Mongolian gerbils (Meriones unguiculatus).

    PubMed

    Kjellstrand, P; Bjerkemo, M; Mortensen, I; Månsson, L; Lanke, J; Holmquist, B

    1981-01-01

    Two groups of Mongolian gerbils (Meriones unguiculatus) were continuously exposed to 150 ppm trichloroethylene (TCE) for 71 and 106 d, respectively. The behavior of the animals was tested in a symmetrical maze baited with sunflower seeds during a period of 23 d, beginning at the end of exposure. One additional group was exposed for 150 d and then allowed 40 d free from exposure before the start of the maze test. Comparisons between the TCE- and air-exposed animals showed differences in the number of correct choices and the number of seeds consumed in the maze, both after 71 and 106 d of exposure and at the end of the 40-d rehabilitation period that followed the 150-d exposure. The results were interpreted in terms of the "emotionality" of the animals. PMID:7338941

  19. Degradation of Trichloroethylene by Methanol-Grown Cultures of Methylosinus trichosporium OB3b PP358

    PubMed Central

    Fitch, M. W.; Speitel, G. E.; Georgiou, G.

    1996-01-01

    A soluble methane monooxygenase-constitutive mutant strain of Methylosinus trichosporium OB3b, strain PP358, was grown with methanol as the carbon source, and the kinetics of trichloroethylene (TCE) degradation were determined. PP358 exhibited high TCE degradation rates under both oxygen- and carbon-limiting conditions. The optimal pseudo first-order rate constant for TCE was comparable to the values measured for cells grown with methane. We found that growth under oxygen-limiting conditions results in increased accumulation of polyhydroxybutyrate, which in turn correlates with higher transformation capacities for TCE. It was also shown that methanol inhibits TCE degradation only at high concentrations. Thus, methanol-grown cultures of PP358 represent an efficient system for the biodegradation of chlorinated hydrocarbons. PMID:16535263

  20. Medium pressure UV combined with chlorine advanced oxidation for trichloroethylene destruction in a model water.

    PubMed

    Wang, Ding; Bolton, James R; Hofmann, Ron

    2012-10-01

    The effectiveness of ultraviolet (UV) combined with chlorine as a novel advanced oxidation process (AOP) for drinking water treatment was evaluated in a bench scale study by comparing the rate of trichloroethylene (TCE) decay when using UV/chlorine to the rates of decay by UV alone and UV/hydrogen peroxide (H₂O₂) at various pH values. A medium pressure mercury UV lamp was used. The UV/chlorine process was more efficient than the UV/H₂O₂ process at pH 5, but in the neutral and alkaline pH range, the UV/H₂O₂ process became more efficient. The pH effect was probably controlled by the increasing concentration of OCl⁻ at higher pH values. A mechanistic kinetic model of the UV/chlorine treatment of TCE showed good agreement with the experimental data. PMID:22763292

  1. Degradation of trichloroethylene by hydrodechlorination using formic acid as hydrogen source over supported Pd catalysts.

    PubMed

    Yu, Xin; Wu, Ting; Yang, Xue-Jing; Xu, Jing; Auzam, Jordan; Semiat, Raphael; Han, Yi-Fan

    2016-03-15

    An advanced method for the degradation of trichloroethylene (TCE) over Pd/MCM-41 catalysts through a hydrogen-transfer was investigated. Formic acid (FA) was used instead of gaseous H2 as the hydrogen resource. As a model H-carrier compound, FA has proven to yield less by-products and second-hand pollution during the reaction. Several factors have been studied, including: the property of catalyst supports, Pd loading and size, temperature, initial concentrations of FA and TCE (potential impact on the reaction rates of TCE degradation), and FA decomposition. The intrinsic kinetics for TCE degradation were measured, while the apparent activation energies and the reaction orders with respect to TCE and FA were calculated through power law models. On the basis of kinetics, we assumed a plausible reaction pathway for TCE degradation in which the catalytic degradation of TCE is most likely the rate-determining step for this reaction. PMID:26685065

  2. Byproduct identification and mechanism determination in plasma chemical decomposition of trichloroethylene

    SciTech Connect

    Futamura, Shigeru; Yamamoto, Toshiaki

    1997-03-01

    Plasma chemical behavior of trichloroethylene (TCE) was investigated with a packed-bed ferroelectric pellet reactor and a pulsed corona reactor. Volatile byproducts were identified by gas chromatography and mass spectrometry (GC-MS), and it was shown that reactor type, TCE concentration, flow rate, background gas, and moisture affected TCE decomposition efficiency and product distribution. Byproduct distributions in nitrogen and the negative effect of oxygen and moisture on TCE decomposition efficiency show that TCE decomposition proceeds via initial elimination of chlorine and hydrogen atoms, the addition of which to TCE accelerates its decomposition. Active oxygen species like OH radical is less likely involved in the initial step of TCE decomposition in plasma. Triplet oxygen molecules ({sup 3}O{sub 2}) scavenge intermediate carbon radicals derived from TCE decomposition to give much lower yields of organic byproducts.

  3. Remediation of trichloroethylene in an artificial aquifer with trees: A controlled field study

    SciTech Connect

    Newman, L.A.; Wang, X.; Muiznieks, I.A.

    1999-07-01

    Poplar trees have been evaluated in the field for the control of contaminated groundwater movement, but to date, the fate of the contaminants has not been demonstrated. In the present study, the authors tested a hybrid poplar for the uptake and degradation of trichloroethylene (TCE). Plants were exposed to TCE-contaminated groundwater under field conditions in lined cells for three years. During the growing seasons, the trees were able to remove over 99% of the added TCE. Less than 9% of the TCE was transpired to the atmosphere during the second and third years, and examination of the tissue showed expected metabolites, but at low levels. Chloride did not significantly accumulate in the plant tissues, but chloride ion increased in the soil in amounts that approximately corresponded to TCE loss. These results demonstrate that treatment of TCE-contaminated groundwater with this poplar clone can result in efficient destruction of TCE.

  4. Use of enrichments and nucleic acid probes in monitoring bioremediation of a deep trichloroethylene plume

    SciTech Connect

    Brockman, F.; Payne, W.; Workman, D.; Soong, A.; Manley, S.; Sun, W.; Ogram, A.

    1994-12-31

    The field site was manipulated with injection of air (control experiment), 1% methane (in air), pulsing of air only and 4% methane, and pulsing of 4% methane supplemented with gaseous forms of nitrogen and phosphorus. Gases were injected through a horizontal well into the aquifer and a vacuum was established in a second horizontal well in the vadose zone. Following each injection regime, sediment samples from the contaminated region were analyzed. Analyses included most-probable-number enrichments for physiological groups known or suspected to degrade trichloroethylene (TCE) and per-chloroethylene (PCE), TCE and PCE removal from enrichments, and DNA extraction and hybridization with various gene probes corresponding to enzymes known to degrade TCE or TCE metabolites.

  5. Possible involvement of toluene-2,3-dioxygenase in defluorination of 3-fluoro-substituted benzenes by toluene-degrading Pseudomonas sp. strain T-12

    SciTech Connect

    Renganathan, V. )

    1989-02-01

    Pseudomonas sp. strain T-12 cells in which the toluene-degradative pathway enzymes have been induced can transform many 3-fluoro-substituted benzenes to the corresponding 2,3-catechols with simultaneous elimination of the fluorine substituent as inorganic fluoride. Substrates for this transformation included 3-fluorotoluen, 3-fluorotrifluorotuluene, 3-fluorohalobenzenes, 3-fluoroanisole, and 3-fluorobenzonitrile. While 3-fluorotoluene and 3-fluoroaniole produced only defluorinated catechols, other substrates generated catechol products with and without the fluorine substituent. The steric size of the C-1 substituent affected the ratio of defluorinated to fluorinated catechols formed from a substrate. A mechanism for the defluorination reaction involving toluene-2,3-dioxygenase is proposed.

  6. Efficient degradation of trichloroethylene in water using persulfate activated by reduced graphene oxide-iron nanocomposite.

    PubMed

    Ahmad, Ayyaz; Gu, Xiaogang; Li, Li; Lv, Shuguang; Xu, Yisheng; Guo, Xuhong

    2015-11-01

    Graphene oxide (GO) and nano-sized zero-valent iron-reduced graphene oxide (nZVI-rGO) composite were prepared. The GO and nZVI-rGO composite were characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR), energy-dispersive spectroscopy (EDS), and Raman spectroscopy. The size of nZVI was about 6 nm as observed by TEM. The system of nZVI-rGO and persulfate (PS) was used for the degradation of trichloroethylene (TCE) in water, and showed 26.5% more efficiency as compared to nZVI/PS system. The different parameters were studied to determine the efficiency of nZVI-rGO to activate the PS system for the TCE degradation. By increasing the PS amount, TCE removal was also improved while no obvious effect was observed by varying the catalyst loading. Degradation was decreased as the TCE initial concentration was increased from 20 to 100 mg/L. Moreover, when initial solution pH was increased, efficiency deteriorated to 80%. Bicarbonate showed more negative effect on TCE removal among the solution matrix. To better understand the effects of radical species in the system, the scavenger tests were performed. The •SO4(-) and •O2(-) were predominant species responsible for TCE removal. The nZVI-rGO-activated PS process shows potential applications in remediation of highly toxic organic contaminants such as TCE present in the groundwater. Graphical abstract Persulfate activated by reduced graphene oxide and nano-sized zero-valent iron composite can be used for efficient degradation of trichloroethylene (TCE) in water. PMID:26162447

  7. Trichloroethylene volatilization enhancement by alcohol/salt cycling injection in unsaturated clayey soils

    NASA Astrophysics Data System (ADS)

    Irizarry, M. L.; Padilla, I. Y.

    2008-05-01

    Trichloroethylene (TCE) is the most widely detected organic contaminant at National Priority List (NPL) sites. In many sites, TCE is trapped as dense non-aqueous phase liquids (DNAPLs) in formations of low permeability, and serve as long-term source of contamination. Remediation of these formations is extremely difficult and expensive. It is, therefore, necessary to develop enhanced, cost effective remediation technologies that can be applied to tight formations of low permeability. This study investigates the applicability of enhanced TCE soil vapor extraction (SVE) from unsaturated clayey soils using capillary delivery of alcohol/salt water cycles. Short chain alcohols are used to modify NAPL air tension and enhance dissolution into the aqueous phase. Brine delivery is used to induce TCE salting out and enhance volatilization. Experimental work involves the use of a 2-D laboratory-scale column packed with tropical clay and contaminated with non-aqueous phase TCE. Rigid porous membranes are inserted into the clay and used to deliver alcohol and brine solutions through competitive capillary forces. Vapor extraction is applied through vacuum well points, whereas a liquid drainage boundary is applied at the bottom of the column. Solution delivery rates and concentrations of TCE, alcohol, and salt solution are monitored to: determine removed and resident mass; assess reactive and transfer processes and develop optimal remedial technologies and parameters (e.g., delivery rates, imposed boundary conditions, contact times). This presentation addresses the preliminary work being conducted to determine the most appropriate alcohol and salt solution. It also discusses the testing of porous membranes of different rigid materials (e.g., stainless steel, Teflon, ceramic) and pore sizes, and the selection of the best one to deliver the selected alcohol and brine solution in unsaturated clays under the imposed boundary conditions. Keywords: Trichloroethylene (TCE), Soil vapor

  8. Is the T-Shaped Toluene Dimer a Stable Intermolecular Complex?

    SciTech Connect

    Gervasio, Francesco; Chelli, Riccardo; Procacci, Piero; Schettino, Vincenzo

    2002-03-28

    By means of molecular mechanics and ab initio calculations, we show that toluene dimer can assume two different minimum energy structures. Both these arrangements are stacked with the methyl groups being parallel and anti-parallel to each other. Although our findings do not agree with the current opinion that one minimum energy structure is T-shaped, they appear to be consistent with available experiments on jet-cooled toluene.

  9. Direct Link between Toluene Degradation in Contaminated-Site Microcosms and a Polaromonas Strain ▿

    PubMed Central

    Sun, Weimin; Xie, Shuguang; Luo, Chunling; Cupples, Alison M.

    2010-01-01

    Stable isotope probing (SIP) was used to identify the aerobic toluene-degrading microorganism in soil microcosms. Several approaches (terminal restriction fragment length polymorphism, 16S rRNA gene sequencing, and quantitative PCR) provided evidence that the microorganism responsible was a member of the genus Polaromonas and could grow on toluene. This microorganism also transformed benzene, but not m-xylene or cis-dichloroethene. PMID:20008173

  10. HCCI experiments with toluene reference fuels modeled by a semidetailed chemical kinetic model

    SciTech Connect

    Andrae, J.C.G.; Brinck, T.; Kalghatgi, G.T.

    2008-12-15

    A semidetailed mechanism (137 species and 633 reactions) and new experiments in a homogeneous charge compression ignition (HCCI) engine on the autoignition of toluene reference fuels are presented. Skeletal mechanisms for isooctane and n-heptane were added to a detailed toluene submechanism. The model shows generally good agreement with ignition delay times measured in a shock tube and a rapid compression machine and is sensitive to changes in temperature, pressure, and mixture strength. The addition of reactions involving the formation and destruction of benzylperoxide radical was crucial to modeling toluene shock tube data. Laminar burning velocities for benzene and toluene were well predicted by the model after some revision of the high-temperature chemistry. Moreover, laminar burning velocities of a real gasoline at 353 and 500 K could be predicted by the model using a toluene reference fuel as a surrogate. The model also captures the experimentally observed differences in combustion phasing of toluene/n-heptane mixtures, compared to a primary reference fuel of the same research octane number, in HCCI engines as the intake pressure and temperature are changed. For high intake pressures and low intake temperatures, a sensitivity analysis at the moment of maximum heat release rate shows that the consumption of phenoxy radicals is rate-limiting when a toluene/n-heptane fuel is used, which makes this fuel more resistant to autoignition than the primary reference fuel. Typical CPU times encountered in zero-dimensional calculations were on the order of seconds and minutes in laminar flame speed calculations. Cross reactions between benzylperoxy radicals and n-heptane improved the model predictions of shock tube experiments for {phi}=1.0 and temperatures lower than 800 K for an n-heptane/toluene fuel mixture, but cross reactions had no influence on HCCI simulations. (author)

  11. Dietary and ethanol induced alterations of the toxikokinetics of toluene in humans.

    PubMed Central

    Hjelm, E W; Löf, A; Sato, A; Colmsjö, A; Lundmark, B O; Norström, A

    1994-01-01

    This study was undertaken to evaluate the influence of a carbohydrate restricted diet, a subacute ethanol intake, and their combined effect on the kinetics of toluene in humans. Eight healthy male volunteers were exposed by inhalation at four different occasions to 200 mg/m3 2H8-toluene for two hours at a work load of 50 W after a one week low (30%) carbohydrate (CH) diet or high (60%) CH diet with (+EtOH) or without (-EtOH) ethanol consumption (47 g ethanol) on the evening before exposure. Deuterium labelled toleune was used to measure the excretion of hippuric acid originating from toluene separately from hippuric acid from other sources. The results indicated that subacute ethanol consumption combined with a carbohydrate restricted diet, may enhance the metabolism of toluene in humans at an exposure concentration of 200 mg/m3. The cumulative amount of hippuric acid excreted in the urine up to 20 hours after the end of exposure in % of the net uptake of toluene was enhanced by 22% (p = 0.05) in the low CH + EtOH compared with the low CH-EtOH experiment. The apparent blood clearance of toluene was 37% higher in the low CH + EtOH than in the low CH-EtOH experiment, but this effect was not statistically significant (p = 0.1). There were no significant changes in the kinetics of toluene as a result of a low carbohydrate diet alone. Neither did subacute ethanol intake without the combination with a carbohydrate restricted diet influence the kinetics of toluene. PMID:8044249

  12. Recovery of organic material by supercritical toluene from Turkish Goynuk oil shale

    SciTech Connect

    Yurum, Y.; Karabakan, A. )

    1990-01-01

    The authors describe the effect of the mineral matrix on the recovery of organic material by supercritical toluene extraction from Turkish Goynuk oil shale. Samples were prepared by successive demineralization procedures to study the interaction of different mineral groups during the supercritical interaction. Extraction experiments were done in a stainless steel autoclave of 75 ml capacity at 350{sup 0}C for 60 minutes. Effect of the toluene/kerogen ratio and reaction time on the recovery of organic material was studied.

  13. Airborne toluene removal for minimizing occupational health exposure by means of a trickle-bed biofilter.

    PubMed

    Raboni, Massimo; Torretta, Vincenzo; Viotti, Paolo

    2016-06-01

    The paper presents the experimental results on a biotrickling pilot plant, with a water scrubber as pre-treatment, finalized to the treatment of an airborne toluene stream in a working place. The air stream was characterized by a very high variability of the inlet concentrations of toluene (range: 4.35-68.20 mg Nm(-3)) with an average concentrations of 16.41 mg Nm(-3). The pilot plant has proved its effectiveness in toluene removal, along a 90-day experimentation period, in steady-state conditions. The scrubbing pre-treatment has achieved an average removal efficiency of 69.9 %, but in particular it has proven its suitability in the rough removal of the toluene peak concentrations, allowing a great stability to the following biological process. The biotrickling stage has achieved an additional average removal efficiency of 75.6 %, confirming the good biodegradability of toluene. The biofilm observation by a scanning confocal laser microscope has evidenced a biofilm thickness of 650 μm fully penetrated by toluene degrading bacteria. Among the micro-population Pseudomonas putida resulted the dominant specie. This bacterium can therefore be considered the responsible for most of the toluene degradation. The whole experimented process has determined an average 92.7 % for toluene removal efficiency. This result meets the most stringent limits and recommendations for occupational safety, given by authoritative organizations in the USA and EU; it also meets the odorous threshold concentration of 11.1 mg Nm(-3). PMID:26946504

  14. High DNP efficiency of TEMPONE radicals in liquid toluene at low concentrations.

    PubMed

    Enkin, Nikolay; Liu, Guoquan; Tkach, Igor; Bennati, Marina

    2014-05-21

    We show that at low concentrations (≤5 mM) TEMPONE radicals in liquid toluene exhibit higher DNP efficiency than in water. In spite of reduced coupling factors, the improved DNP performance in toluene results from favourable saturation and leakage factors, as determined by pulse electron-electron double resonance (ELDOR) and NMR relaxation, respectively. The extracted coupling factors at 0.35 Tesla support theoretical predictions of the Overhauser mechanism. PMID:24695794

  15. Microbial Toluene Removal in Hypoxic Model Constructed Wetlands Occurs Predominantly via the Ring Monooxygenation Pathway.

    PubMed

    Martínez-Lavanchy, P M; Chen, Z; Lünsmann, V; Marin-Cevada, V; Vilchez-Vargas, R; Pieper, D H; Reiche, N; Kappelmeyer, U; Imparato, V; Junca, H; Nijenhuis, I; Müller, J A; Kuschk, P; Heipieper, H J

    2015-09-01

    In the present study, microbial toluene degradation in controlled constructed wetland model systems, planted fixed-bed reactors (PFRs), was queried with DNA-based methods in combination with stable isotope fractionation analysis and characterization of toluene-degrading microbial isolates. Two PFR replicates were operated with toluene as the sole external carbon and electron source for 2 years. The bulk redox conditions in these systems were hypoxic to anoxic. The autochthonous bacterial communities, as analyzed by Illumina sequencing of 16S rRNA gene amplicons, were mainly comprised of the families Xanthomonadaceae, Comamonadaceae, and Burkholderiaceae, plus Rhodospirillaceae in one of the PFR replicates. DNA microarray analyses of the catabolic potentials for aromatic compound degradation suggested the presence of the ring monooxygenation pathway in both systems, as well as the anaerobic toluene pathway in the PFR replicate with a high abundance of Rhodospirillaceae. The presence of catabolic genes encoding the ring monooxygenation pathway was verified by quantitative PCR analysis, utilizing the obtained toluene-degrading isolates as references. Stable isotope fractionation analysis showed low-level of carbon fractionation and only minimal hydrogen fractionation in both PFRs, which matches the fractionation signatures of monooxygenation and dioxygenation. In combination with the results of the DNA-based analyses, this suggests that toluene degradation occurs predominantly via ring monooxygenation in the PFRs. PMID:26150458

  16. Microbial Toluene Removal in Hypoxic Model Constructed Wetlands Occurs Predominantly via the Ring Monooxygenation Pathway

    PubMed Central

    Martínez-Lavanchy, P. M.; Chen, Z.; Lünsmann, V.; Marin-Cevada, V.; Vilchez-Vargas, R.; Pieper, D. H.; Reiche, N.; Kappelmeyer, U.; Imparato, V.; Junca, H.; Nijenhuis, I.; Müller, J. A.; Kuschk, P.

    2015-01-01

    In the present study, microbial toluene degradation in controlled constructed wetland model systems, planted fixed-bed reactors (PFRs), was queried with DNA-based methods in combination with stable isotope fractionation analysis and characterization of toluene-degrading microbial isolates. Two PFR replicates were operated with toluene as the sole external carbon and electron source for 2 years. The bulk redox conditions in these systems were hypoxic to anoxic. The autochthonous bacterial communities, as analyzed by Illumina sequencing of 16S rRNA gene amplicons, were mainly comprised of the families Xanthomonadaceae, Comamonadaceae, and Burkholderiaceae, plus Rhodospirillaceae in one of the PFR replicates. DNA microarray analyses of the catabolic potentials for aromatic compound degradation suggested the presence of the ring monooxygenation pathway in both systems, as well as the anaerobic toluene pathway in the PFR replicate with a high abundance of Rhodospirillaceae. The presence of catabolic genes encoding the ring monooxygenation pathway was verified by quantitative PCR analysis, utilizing the obtained toluene-degrading isolates as references. Stable isotope fractionation analysis showed low-level of carbon fractionation and only minimal hydrogen fractionation in both PFRs, which matches the fractionation signatures of monooxygenation and dioxygenation. In combination with the results of the DNA-based analyses, this suggests that toluene degradation occurs predominantly via ring monooxygenation in the PFRs. PMID:26150458

  17. Are biogenic emissions a significant source of summertime atmospheric toluene in rural Northeastern United States?

    NASA Astrophysics Data System (ADS)

    White, M. L.; Russo, R. S.; Zhou, Y.; Ambrose, J. L.; Haase, K.; Frinak, E. K.; Varner, R. K.; Wingenter, O. W.; Mao, H.; Talbot, R.; Sive, B. C.

    2008-06-01

    Summertime atmospheric toluene enhancements at Thompson Farm in the rural northeastern United States were unexpected and resulted in a toluene/benzene seasonal pattern that was distinctly different from that of other anthropogenic volatile organic compounds. Consequentially, three hydrocarbon sources were investigated for potential contributions to the enhancements during 2004 2006. These included: 1) increased warm season fuel evaporation coupled with changes in reformulated gasoline (RFG) content to meet U.S. EPA summertime volatility standards, 2) local industrial emissions and 3) local vegetative emissions. The contribution of fuel evaporation emission to summer toluene mixing ratios was estimated to range from 16 to 30 pptv d-1, and did not fully account for the observed enhancements (20 50 pptv) in 2004 2006. Static chamber measurements of alfalfa, a crop at Thompson Farm, and dynamic branch enclosure measurements of loblolly pine trees in North Carolina suggested vegetative emissions of 5 and 12 pptv d-1 for crops and coniferous trees, respectively. Toluene emission rates from alfalfa are potentially much larger as these plants were only sampled at the end of the growing season. Measured biogenic fluxes were on the same order of magnitude as the influence from gasoline evaporation and industrial sources (regional industrial emissions estimated at 7 pptv d-1) and indicated that local vegetative emissions make a significant contribution to summertime toluene enhancements. Additional studies are needed to characterize the variability and factors controlling toluene emissions from alfalfa and other vegetation types throughout the growing season.

  18. Are biogenic emissions a significant source of summertime atmospheric toluene in the rural Northeastern United States?

    NASA Astrophysics Data System (ADS)

    White, M. L.; Russo, R. S.; Zhou, Y.; Ambrose, J. L.; Haase, K.; Frinak, E. K.; Varner, R. K.; Wingenter, O. W.; Mao, H.; Talbot, R.; Sive, B. C.

    2009-01-01

    Summertime atmospheric toluene enhancements at Thompson Farm in the rural northeastern United States were unexpected and resulted in a toluene/benzene seasonal pattern that was distinctly different from that of other anthropogenic volatile organic compounds. Consequently, three hydrocarbon sources were investigated for potential contributions to the enhancements during 2004-2006. These included: (1) increased warm season fuel evaporation coupled with changes in reformulated gasoline (RFG) content to meet US EPA summertime volatility standards, (2) local industrial emissions and (3) local vegetative emissions. The contribution of fuel evaporation emission to summer toluene mixing ratios was estimated to range from 16 to 30 pptv d-1, and did not fully account for the observed enhancements (20-50 pptv) in 2004-2006. Static chamber measurements of alfalfa, a crop at Thompson Farm, and dynamic branch enclosure measurements of loblolly pine trees in North Carolina suggested vegetative emissions of 5 and 12 pptv d-1 for crops and coniferous trees, respectively. Toluene emission rates from alfalfa are potentially much larger as these plants were only sampled at the end of the growing season. Measured biogenic fluxes were on the same order of magnitude as the influence from gasoline evaporation and industrial sources (regional industrial emissions estimated at 7 pptv d-1 and indicated that local vegetative emissions make a significant contribution to summertime toluene enhancements. Additional studies are needed to characterize the variability and factors controlling toluene emissions from alfalfa and other vegetation types throughout the growing season.

  19. [Removal of toluene waste gas by Pseudomonas putida with a bio-trickling filter].

    PubMed

    Zhang, Shu-Jing; Li, Jian; Li, Yi-Li; Jin, Yu-Quan; Sun, Li

    2007-08-01

    In transient conditions close to the industrialized application situation, the removal of toluene was investigated with a lab-scale bio-trickling filter inoculated with pure bacterial culture (Pseudomonas putida). The start-up process and the ability of resisting different toluene loading in the steady state on the performance of the bio-trickling filter were studied. The microstructure of biofilm in the filter was also observed. With inlet concentration range from 544 to 1044 mg x m(-3) at the temperature ranging from 17 to 26 degrees C, the removal efficiency of toluene was almost 100% at the residence time of 54 s and 43.2 s. The maximum volumetric removal loading of 105.35 g x (m3 x h)(-1) was achieved. The results indicate that it was feasible to remove toluene by Pseudomonas putida which had not be acclimated by toluene. In the steady state, the bio-trickling filter had a high flexibility for the load change and the removal efficiency of the reactor was not influenced by the variance of residence time and inlet concentration. The rapid increase of biofilm can be controlled by adjusting the interval of nutrition liquid accession. There were some changes in bacterial community, and lots of micro-pore existed in the biofilm. It was proved that the absorption of the biofilm was an important precondition for the biodegradation of toluene. PMID:17926425

  20. Removal of gaseous toluene using immobilized Candida tropicalis in a fluidized bed bioreactor.

    PubMed

    Ahmed, Zubair; Song, Jihyeon

    2011-09-01

    A pure yeast strain Candida tropicalis was immobilized on the matrix of powdered activated carbon, sodium alginate, and polyethylene glycol (PSP beads). The immobilized beads were used as fluidized material in a bioreactor to remove toluene from gaseous stream. Applied toluene loadings were 15.4 and 29.8 g/m(3) h in Step 1 and Step 2, respectively, and toluene removal was found above 95% during the entire operation. A continuous pH decline was observed and pH of the suspension was just above 6 in Step 2 but no adverse effects on treatment efficiency were observed. The CO(2) yield values were found to be 0.57 and 0.62 g-[Formula: see text] in Step 1 and Step 2, respectively. These values indicate that a major portion of toluene-carbon was channeled to yeast respiration even at higher toluene loading. In conclusion, immobilized C. tropicalis can be used as a fluidized material for enhanced degradation of gaseous toluene. PMID:22582151

  1. Potential application of biocover soils to landfills for mitigating toluene emission.

    PubMed

    Su, Yao; Pei, Junshen; Tian, Baohu; Fan, Fengxi; Tang, Mengling; Li, Wei; He, Ruo

    2015-12-15

    Biocover soils have been demonstrated to be a good alternative cover material to mitigate CH4 emission from landfills. To evaluate the potential of biocover soil in mitigating emissions of non-methane volatile organic compounds (NMVOCs) from landfills, simulated cover soil columns with the influx of toluene (chosen as typical of NMVOCs) concentrations of 102-1336 mg m(-3) in the presence or absence of the major landfill gas components (i.e., CH4 and CO2) were conducted in this study. In the two experimental materials (waste biocover soils (WBS) and landfill cover soils (LCS)), higher toluene reduction was observed in WBS with respect to LCS. After the introduction of landfill gas, an increase of microbial diversity and relative abundance of toluene-degrading bacteria and methanotrophs occurred in WBS. To illustrate the role of toluene-degrading activity in mitigating toluene emissions through landfill covers, an analytical model was developed by incorporating the steady-state vapor transport with the first-order kinetics of aerobic biodegradation limited by O2 availability. This study demonstrated that biocover soils have great potential in applying to landfills for mitigating toluene emission to the atmosphere. PMID:26073517

  2. A detailed kinetic modeling study of toluene oxidation in a premixed laminar flame

    PubMed Central

    Tian, Zhenyu; Pitz, William J.; Fournet, René; Glaude, Pierre-Alexander; Battin-Leclerc, Frédérique

    2013-01-01

    An improved chemical kinetic model for the toluene oxidation based on experimental data obtained in a premixed laminar low-pressure flame with vacuum ultraviolet (VUV) photoionization and molecular beam mass spectrometry (MBMS) techniques has been proposed. The present mechanism consists of 273 species up to chrysene and 1740 reactions. The rate constants of reactions of toluene decomposition, reaction with oxygen, ipso-additions and metatheses with abstraction of phenylic H-atom are updated; new pathways of C4 + C2 species giving benzene and fulvene are added. Based on the experimental observations, combustion intermediates such as fulvenallene, naphtol, methylnaphthalene, acenaphthylene, 2-ethynylnaphthalene, phenanthrene, anthracene, 1-methylphenanthrene, pyrene and chrysene are involved in the present mechanism. The final toluene model leads to an overall satisfactory agreement between the experimentally observed and predicted mole fraction profiles for the major products and most combustion intermediates. The toluene depletion is governed by metathese giving benzyl radicals, ipso-addition forming benzene and metatheses leading to C6H4CH3 radicals. A sensitivity analysis indicates that the unimolecular decomposition via the cleavage of a methyl C-H bond has a strong inhibiting effect, while decomposition via C-C bond breaking, ipso-addition of H-atom to toluene, decomposition of benzyl radicals and reactions related to C6H4CH3 radicals have promoting effect for the consumption of toluene. Moreover, flow rate analysis is performed to illustrate the formation pathways of mono- and polycyclic aromatics. PMID:23762016

  3. Production of toluene cis-glycol by Pseudomonas putida in glucose fed-batch culture

    SciTech Connect

    Jenkins, R.O.; Stephens, G.M.; Dalton, H.

    1987-05-01

    Toluene was oxidized by a mutant strain of Pseudomonas putida (strain NG1) to toluene cis-glycol (TCG). Product was accumulated in fed-batch cultures to concentrations (18-24 g/L) higher than hitherto achieved. In vitro activities of toluene dioxygenase from P. putida NG1 were fivefold lower than that from the toluene-grown wild-type organism, whereas comparable activities of both catechol 2,3- and catechol 1,2-oxygenase were obtained; irreversible inhibition of toluene dioxygenase activity by TCG was shown in vitro. Ammonia deprivation during the production phase limited the growth of revertant organisms but had little effect on either the duration (25 h) of the process or the final concentration of TCG achieved. The rates of glucose utilization decreased throughout the biotransformation and cell death accompanied the cessation of TCG accumulation in cultures. The results suggest that TCG is the mediator of a gradual deterioration in the state of the culture which leads to a loss of both in vivo and in vitro toluene dioxygenase activity and a marked decrease in culture viability.

  4. Degradation of toluene by ortho cleavage enzymes in Burkholderia fungorum FLU100

    PubMed Central

    Dobslaw, Daniel; Engesser, Karl-Heinrich

    2015-01-01

    Burkholderia fungorum FLU100 simultaneously oxidized any mixture of toluene, benzene and mono-halogen benzenes to (3-substituted) catechols with a selectivity of nearly 100%. Further metabolism occurred via enzymes of ortho cleavage pathways with complete mineralization. During the transformation of 3-methylcatechol, 4-carboxymethyl-2-methylbut-2-en-4-olide (2-methyl-2-enelactone, 2-ML) accumulated transiently, being further mineralized only after a lag phase of 2 h in case of cells pre-grown on benzene or mono-halogen benzenes. No lag phase, however, occurred after growth on toluene. Cultures inhibited by chloramphenicol after growth on benzene or mono-halogen benzenes were unable to metabolize 2-ML supplied externally, even after prolonged incubation. A control culture grown with toluene did not show any lag phase and used 2-ML as a substrate. This means that 2-ML is an intermediate of toluene degradation and converted by specific enzymes. The conversion of 4-methylcatechol as a very minor by-product of toluene degradation in strain FLU100 resulted in the accumulation of 4-carboxymethyl-4-methylbut-2-en-4-olide (4-methyl-2-enelactone, 4-ML) as a dead-end product, excluding its nature as a possible intermediate. Thus, 3-methylcyclohexa-3,5-diene-1,2-diol, 3-methylcatechol, 2-methyl muconate and 2-ML were identified as central intermediates of productive ortho cleavage pathways for toluene metabolism in B. fungorum FLU100. PMID:25130674

  5. Detection of hydroxyl radical in plasma reaction on toluene removal.

    PubMed

    Guo, Yufang; Liao, Xiaobin; Ye, Daiqi

    2008-01-01

    A new method was introduced to detect the concentration of OH radical in dielectric barrier discharge (DBD) reaction. A film, which was impregnated with salicylic acid, was used to detect OH radical in plasma reaction at room temperature and atmospheric pressure. Salicylic acid reacts with OH radical and produces 2,5-dihydroxybenzoic acid (2,5-DHBA). Then, a high performance liquid chromatography (HPLC) was carried out to detect the concentration of 2,5-DHBA. Therefore, OH radical in nonthermal plasma reaction could be calculated. In this plasma reaction, the applied voltage was controlled at 10 kV, the initial concentration of toluene was 400 mg/m3, and the gas flow rate was 300 ml/min. It was observed that when the film was placed away from the plasma area, 2,5-DHBA could not be detected by HPLC, although the sampling time lasted for 48 h. On the other hand, when the film was placed in the plasma area and the sampling time being too long (> 4 h), the concentration of 2,5-DHBA was also below detection limit, and it could not be detected by HPLC. However, when the film was placed in the plasma reaction field with the sampling time being 3 h, the concentration of OH radical was calculated to be 10.54 x 10(12) cm(-3). In addition, concentration of OH radical was investigated under different humidity, such as 0.2%, 0.4%, 0.6%, 0.8%, and 1.0%. The results showed that the amount of OH radical stayed at order of magnitude of 10(12) cm(-3) and increased with the increase of humidity. PMID:19209627

  6. Developmental toxicity of toluene in male rats: effects on semen quality, testis morphology, and apoptotic neurodegeneration.

    PubMed

    Dalgaard, M; Hossaini, A; Hougaard, K S; Hass, U; Ladefoged, O

    2001-04-01

    In one study, pregnant Wistar rats were exposed to 1200 ppm toluene by inhalation 6 h a day from gestational day (GD) 7 to postnatal day (PND) 18. Sperm analysis was performed in the adult male offspring at PND 110 by using computer-assisted sperm analysis. Toluene did not affect the semen quality of exposed rats. In another study, pregnant rats were exposed to 1800 ppm from GD 7 to GD 20, and the male offspring were killed at PND 11, 21 or 90. Paired testes weight, histopathology and immunoexpression of vimentin in Sertoli cells were used as markers of testis toxicity. In the brain, the number of apoptotic cells in the hippocampus and cerebellum were counted after visualisation by means of the TUNEL assay. Mean body weight in pups of exposed dams was lower than in pups from control litters. This decrease was still statistically significant at PND 11, but at PND 21 and 90 the body weight of toluene-exposed males tended to approach that of the controls. Absolute and relative testes weights were reduced in all three age groups, although not to a statistically significant degree. Histopathological examinations of the testis and immuno-expression of vimentin did not reveal any differences between toluene-exposed animals and control animals. In the hippocampus, almost no apoptosis was observed in any age group, and there were no differences in apoptotic neurodegeneration between male rats exposed to 1800 ppm and control animals at PND 11, 21 or 90. Generally, a marked increase in number of apoptotic cells was observed in cerebellar granule cells at PND 21 compared with the other age groups. Toluene induced a statistically significant increase in the number of apoptotic cells in the cerebellar granule layer at PND 21. The mean was increased from 37 in the control group to 71 in the toluene-exposed group. Thus, the granular cell layer in cerebellum is a highly relevant tissue with which to study toluene-induced apoptosis, because of the continuous migration of neurons and

  7. Kinetic effects of toluene blending on the extinction limit of n-decane diffusion flames

    SciTech Connect

    Won, Sang Hee; Sun, Wenting; Ju, Yiguang

    2010-03-15

    The impact of toluene addition in n-decane on OH concentrations, maximum heat release rates, and extinction limits were studied experimentally and computationally by using counterflow diffusion flames with laser induced fluorescence imaging. Sensitivity analyses of kinetic path ways and species transport on flame extinction were also conducted. The results showed that the extinction strain rate of n-decane/toluene/nitrogen flames decreased significantly with an increase of toluene addition and depended linearly on the maximum OH concentration. It was revealed that the maximum OH concentration, which depends on the fuel H/C ratio, can be used as an index of the radical pool and chemical heat release rate, since it plays a significant role on the heat production via the reaction with other species, such as CO, H{sub 2}, and HCO. Experimental results further demonstrated that toluene addition in n-decane dramatically reduced the peak OH concentration via H abstraction reactions and accelerated flame extinction via kinetic coupling between toluene and n-decane mechanisms. Comparisons between experiments and simulations revealed that the current toluene mechanism significantly over-predicts the radical destruction rate, leading to under-prediction of extinction limits and OH concentrations, especially caused by the uncertainty of the H abstraction reaction from toluene, which rate coefficient has a difference by a factor of 5 in the tested toluene models. In addition, sensitivity analysis of diffusive transport showed that in addition to n-decane and toluene, the transport of OH and H also considerably affects the extinction limit. A reduced linear correlation between the extinction limits of n-decane/toluene blended fuels and the H/C ratio as well as the mean fuel molecular weight was obtained. The results suggest that an explicit prediction of the extinction limits of aromatic and alkane blended fuels can be established by using H/C ratio (or radical index) and the

  8. A high pressure mass spectrometric study of the binding of (CH3)3Si+ and (CH3)3C+ to toluene and benzene

    NASA Astrophysics Data System (ADS)

    Stone, Jennifer M.; Stone, John A.

    1991-11-01

    The equilibria (CH3)3X+ + aromatic [right harpoon over left] (CH3)3X · aromatic+ (X = Si, C; AROMATIC = toluene, toluene-d8) have been studied by high pressure mass spectrometry. Van't Hoff plots yield the following [Delta]H° values (kcal mol-1): X = Si, toluene -28.4 ± 0.4, toluene-d8 - 31.3 ± 0.3; X = C, toluene - 29.1 ± 0.3, toluene-d8 -28.6 ± 0.8 and [Delta]S° values (cal K-1 mol-1): X --- Si, toluene -33.6 ± 1.9, toluene-d8 -39.3 ± 1.9; X = C, toluene -54.6 ± 0.8, toluene-d8 - 54.5 ± 2.4. Deuteron transfer from (CH3)3CC7D+8 to the strong base (C2H5)3N provides definite proof that the complex is an arenium ion. Less convincing experimental evidence is provided for (CH3)3SiC7D+8 being an arenium ion although thermodynamic data derived from the binding enthalpy are consistent with such a structure.

  9. Simulation of solute transport of tetrachloroethylene in ground water of the glacial-drift aquifer at the Savage Municipal Well Superfund Site, Milford, New Hampshire, 1960-2000

    USGS Publications Warehouse

    Harte, Philip T.

    2004-01-01

    The Savage Municipal Well Superfund site, named after the former municipal water-supply well for the town of Milford, is underlain by a 0.5-square mile plume of volatile organic compounds (VOCs), primarily tetrachloroethylene (PCE). The plume occurs mostly within a highly transmissive sand-and-gravel unit, but also extends to an underlying till and bedrock unit. The plume logistically is divided into two areas termed Operable Unit No. 1 (OU1), which contains the primary source area, and Operable Unit No. 2 (OU2), which is the extended plume area. PCE concentrations in excess of 100,000 parts per billion (ppb) had been detected in the OU1 area in 1995, indicating a likely Dense Non-Aqueous Phase Liquid (DNAPL) source. In the fall of 1998, the New Hampshire Department of Environmental Services (NHDES) and the U.S. Environmental Protection Agency (USEPA) installed a remedial system in OU1. The OU1 remedial system includes a low-permeability barrier that encircles the highest detected concentrations of PCE, and a series of injection and extraction wells. The barrier primarily sits atop bedrock and penetrates the full thickness of the sand and gravel; and in some places, the full thickness of the underlying basal till. The sand and gravel unit and the till comprise the aquifer termed the Milford-Souhegan glacial-drift aquifer (MSGD). Two-dimensional and three-dimensional finite-difference solute-transport models of the unconsolidated sediments (MSGD aquifer) were constructed to help evaluate solute-transport processes, assess the effectiveness of remedial activities in OU1, and to help design remedial strategies in OU2. The solute-transport models simulate PCE concentrations, and model results were compared to observed concentrations of PCE. Simulations were grouped into the following three time periods: an historical calibration of the distribution of PCE from the initial input (circa 1960) of PCE into the subsurface to the 1990s, a pre-remedial calibration from 1995

  10. Description of toluene inhibition of methyl bromide biodegradation in seawater and isolation of a marine toluene oxidizer that degrades methyl bromide.

    PubMed

    Goodwin, Kelly D; Tokarczyk, Ryszard; Stephens, F Carol; Saltzman, Eric S

    2005-07-01

    Methyl bromide (CH3Br) and methyl chloride (CH3Cl) are important precursors for destruction of stratospheric ozone, and oceanic uptake is an important component of the biogeochemical cycle of these methyl halides. In an effort to identify and characterize the organisms mediating halocarbon biodegradation, we surveyed the effect of potential cometabolic substrates on CH3Br biodegradation using a 13CH3Br incubation technique. Toluene (160 to 200 nM) clearly inhibited CH3Br and CH3Cl degradation in seawater samples from the North Atlantic, North Pacific, and Southern Oceans. Furthermore, a marine bacterium able to co-oxidize CH3Br while growing on toluene was isolated from subtropical Western Atlantic seawater. The bacterium, Oxy6, was also able to oxidize o-xylene and the xylene monooxygenase (XMO) pathway intermediate 3-methylcatechol. Patterns of substrate oxidation, lack of acetylene inhibition, and the inability of the toluene 4-monooxygenase (T4MO)-containing bacterium Pseudomonas mendocina KR1 to degrade CH3Br ruled out participation of the T4MO pathway in Oxy6. Oxy6 also oxidized a variety of toluene (TOL) pathway intermediates such as benzyl alcohol, benzylaldehyde, benzoate, and catechol, but the inability of Pseudomonas putida mt-2 to degrade CH3Br suggested that the TOL pathway might not be responsible for CH3Br biodegradation. Molecular phylogenetic analysis identified Oxy6 to be a member of the family Sphingomonadaceae related to species within the Porphyrobacter genus. Although some Sphingomonadaceae can degrade a variety of xenobiotic compounds, this appears to be the first report of CH3Br degradation for this class of organism. The widespread inhibitory effect of toluene on natural seawater samples and the metabolic capabilities of Oxy6 indicate a possible link between aromatic hydrocarbon utilization and the biogeochemical cycle of methyl halides. PMID:16000753

  11. Enhanced Anaerobic Biodegradation of Benzene-Toluene-Ethylbenzene-Xylene-Ethanol Mixtures in Bioaugmented Aquifer Columns

    PubMed Central

    Da Silva, Marcio L. B.; Alvarez, Pedro J. J.

    2004-01-01

    Methanogenic flowthrough aquifer columns were used to investigate the potential of bioaugmentation to enhance anaerobic benzene-toluene-ethylbenzene-xylene (BTEX) degradation in groundwater contaminated with ethanol-blended gasoline. Two different methanogenic consortia (enriched with benzene or toluene and o-xylene) were used as inocula. Toluene was the only hydrocarbon degraded within 3 years in columns that were not bioaugmented, although anaerobic toluene degradation was observed after only 2 years of acclimation. Significant benzene biodegradation (up to 88%) was observed only in a column bioaugmented with the benzene-enriched methanogenic consortium, and this removal efficiency was sustained for 1 year with no significant decrease in permeability due to bioaugmentation. Benzene removal was hindered by the presence of toluene, which is a more labile substrate under anaerobic conditions. Real-time quantitative PCR analysis showed that the highest numbers of bssA gene copies (coding for benzylsuccinate synthase) occurred in aquifer samples exhibiting the highest rate of toluene degradation, which suggests that this gene could be a useful biomarker for environmental forensic analysis of anaerobic toluene bioremediation potential. bssA continued to be detected in the columns 1 year after column feeding ceased, indicating the robustness of the added catabolic potential. Overall, these results suggest that anaerobic bioaugmentation might enhance the natural attenuation of BTEX in groundwater contaminated with ethanol-blended gasoline, although field trials would be needed to demonstrate its feasibility. This approach may be especially attractive for removing benzene, which is the most toxic and commonly the most persistent BTEX compound under anaerobic conditions. PMID:15294807

  12. Inhibition and gene expression of Nitrosomonas europaea biofilms exposed to phenol and toluene.

    PubMed

    Lauchnor, Ellen G; Radniecki, Tyler S; Semprini, Lewis

    2011-04-01

    Pure culture biofilms of the ammonia-oxidizing bacterium Nitrosomonas europaea were grown in a Drip Flow Biofilm Reactor and exposed to the aromatic hydrocarbons phenol and toluene. Ammonia oxidation rates, as measured by nitrite production in the biofilms, were inhibited 50% when exposed to 56 µM phenol or 100 µM toluene, while 50% inhibition of suspended cells occurred at 8 µM phenol or 20 µM toluene. Biofilm-grown cells dispersed into liquid medium and immediately exposed to phenol or toluene experienced similar inhibition levels as batch grown cells, indicating that mass transfer may be a factor in N. europaea biofilm resistance. Whole genome microarray analysis of gene expression was used to detect genes up-regulated in biofilms during toluene and phenol exposure. Two genes, a putative pirin protein (NE1545) and a putative inner membrane protein (NE1546) were up-regulated during phenol exposure, but no genes were up-regulated during toluene exposure. Using qRT-PCR, up-regulation of NE1545 was detected in biofilms and suspended cells exposed to a range of phenol concentrations and levels of inhibition. In the biofilms, NE1545 expression was up-regulated an average of 13-fold over the range of phenol concentrations tested, and was essentially independent of phenol concentration. However, the expression of NE1545 in suspended cells increased from 20-fold at 7 µM phenol up to 80-fold at 30 µM phenol. This study demonstrates that biofilms of N. europaea are more resistant than suspended cells to inhibition of ammonia oxidation by phenol and toluene, even though the global transcriptional responses to the inhibitors do not differ in N. europaea between the suspended and attached growth states. PMID:21404249

  13. Functional redundancy in phenol and toluene degradation in Pseudomonas stutzeri strains isolated from the Baltic Sea.

    PubMed

    Heinaru, Eeva; Naanuri, Eve; Grünbach, Maarja; Jõesaar, Merike; Heinaru, Ain

    2016-09-01

    In the present study we describe functional redundancy of bacterial multicomponent monooxygenases (toluene monooxygenase (TMO) and toluene/xylene monooxygenase (XylAM) of TOL pathway) and cooperative genetic regulation at the expression of the respective catabolic operons by touR and xylR encoded regulatory circuits in five phenol- and toluene-degrading Pseudomonas stutzeri strains. In these strains both toluene degradation pathways (TMO and Xyl) are active and induced by toluene and phenol. The whole genome sequence of the representative strain 2A20 revealed the presence of complete TMO- and Xyl-upper pathway operons together with two sets of lower catechol meta pathway operons, as well as phenol-degrading operon in a single 292,430bp contig. The much lower GC content and analysis of the predicted ORFs refer to the plasmid origin of the approximately 130kb region of this contig, containing the xyl, phe and tou genes. The deduced amino acid sequences of the TMO, XylA and the large subunit of phenol monooxygenase (LmPH) show 98-100% identity with the respective gene products of the strain Pseudomonas sp. OX1. In both strains 2A20 and OX1 the meta-cleavage pathways for catechol degradation are coded by two redundant operons (phe and xyl). We show that in the strain 2A20 TouR and XylR are activated by different effector molecules, phenol and toluene, respectively, and they both control transcription of the xyl upper, tou (TMO) and phe catabolic operons. Although the growth parameters of redundant strains did not show advantage at toluene biodegradation, the functional redundancy could provide better flexibility to the bacteria in environmental conditions. PMID:27185632

  14. Alterations in Rat Fetal Morphology Following Abuse Patterns of Toluene Exposure

    PubMed Central

    Bowen, Scott E.; Irtenkauf, Susan; Hannigan, John H.; Stefanski, Adrianne L.

    2009-01-01

    Toluene is a commonly abused organic solvent. Inhalant abusers are increasingly women in their prime childbearing years. Children born to mothers who abused solvents during pregnancy may exhibit characteristics of a “fetal solvent syndrome” which may include dysmorphic features. This study examined the teratological effects of an abuse pattern of binge toluene exposure during gestation on skeletal and soft tissue abnormalities, body weight, and body size in fetal rats. Pregnant Sprague–Dawley rats were exposed for 30 min, twice daily, from gestational day (GD) 8 through GD20 to either air (0 ppm), 8,000 ppm, 12,000 ppm, or 16,000 ppm toluene. Two-thirds of each litter was prepared for skeletal examination using Alizarin Red S staining while the remaining third of each litter was fixed in Bouin’s solution for Wilson’s soft tissue evaluation. Exposure to toluene at all levels significantly reduced growth, including decreases in placental weight, fetal weight, and crown-rump length. In addition, numerous gross morphological anomalies were observed such as short or missing digits and missing limbs. Skeletal examination revealed that ossification of the extremities was significantly reduced as a result of toluene exposure at all levels. Specific skeletal defects included misshapen scapula, missing and supernumerary vertebrae and ribs, and fused digits. Soft tissue anomalies were also observed at all toluene levels and there was a dose-dependent increase in the number of anomalies which included cryptorchidism, displaced abdominal organs, gastromegaly, distended/hypoplastic bladder, and delayed cardiac development, among others. These results indicate that animals exposed prenatally to levels and patterns of toluene typical of inhalant abuse are at increased risk for skeletal and soft tissue abnormalities. PMID:19429395

  15. Developmental and reproductive toxicity evaluation of toluene vapor in the rat. I. Reproductive toxicity.

    PubMed

    Roberts, L G; Bevans, A C; Schreiner, C A

    2003-01-01

    The reproductive toxicity of toluene was evaluated in a 2-generation test in which male and female Sprague-Dawley rats, parental (F0) and first generation (F1), were exposed to toluene via whole body inhalation, 6 h/day, 7 days/week for 80 days premating and 15 days of mating at concentrations of 0, 100, 500 and 2000 ppm (0, 375, 1875 and 7500 mg/m(3)). Toluene was administered at 2000 ppm to both sexes, or to females or males only to be mated with untreated partners. Pregnant females at all dose levels were exposed from gestation day (GD) 1-20 and lactation day (LD) 5-21. At LD5, females were removed from their litters for daily exposure and returned when 6 h of exposure was completed. F1 pups selected to produce the F2 generation were treated for 80 days beginning immediately after weaning (LD21) and initially mated at a minimum of 100 days of age. F2 pups were not exposed to toluene by inhalation. Toluene exposure did not induce adverse effects on fertility, reproductive performance, or maternal/pup behaviors during the lactation period in males and females of the parental or first generation, but did inhibit growth in F1 and F2 offspring in the 2000 ppm (both sexes treated) and 2000 ppm (females only treated) groups. Caesarean section of selected 2000 ppm (both sexes treated) dams at GD20 showed reduced fetal body weight and skeletal variations. Exposure to toluene caused decreased pup weights throughout lactation in F1 and F2 2000 ppm (both sexes treated), and 2000 ppm (females only treated) groups. Exposure at 2000 ppm to male parents only did not induce similar weight inhibition in offspring. The toluene offspring NOAEL is 500 ppm in groups in which maternal animals were exposed, and 2000 ppm for male only treated groups. PMID:14613816

  16. Anodes Stimulate Anaerobic Toluene Degradation via Sulfur Cycling in Marine Sediments.

    PubMed

    Daghio, Matteo; Vaiopoulou, Eleni; Patil, Sunil A; Suárez-Suárez, Ana; Head, Ian M; Franzetti, Andrea; Rabaey, Korneel

    2016-01-01

    Hydrocarbons released during oil spills are persistent in marine sediments due to the absence of suitable electron acceptors below the oxic zone. Here, we investigated an alternative bioremediation strategy to remove toluene, a model monoaromatic hydrocarbon, using a bioanode. Bioelectrochemical reactors were inoculated with sediment collected from a hydrocarbon-contaminated marine site, and anodes were polarized at 0 mV and +300 mV (versus an Ag/AgCl [3 M KCl] reference electrode). The degradation of toluene was directly linked to current generation of up to 301 mA m(-2) and 431 mA m(-2) for the bioanodes polarized at 0 mV and +300 mV, respectively. Peak currents decreased over time even after periodic spiking with toluene. The monitoring of sulfate concentrations during bioelectrochemical experiments suggested that sulfur metabolism was involved in toluene degradation at bioanodes. 16S rRNA gene-based Illumina sequencing of the bulk anolyte and anode samples revealed enrichment with electrocatalytically active microorganisms, toluene degraders, and sulfate-reducing microorganisms. Quantitative PCR targeting the α-subunit of the dissimilatory sulfite reductase (encoded by dsrA) and the α-subunit of the benzylsuccinate synthase (encoded by bssA) confirmed these findings. In particular, members of the family Desulfobulbaceae were enriched concomitantly with current production and toluene degradation. Based on these observations, we propose two mechanisms for bioelectrochemical toluene degradation: (i) direct electron transfer to the anode and/or (ii) sulfide-mediated electron transfer. PMID:26497463

  17. Anodes Stimulate Anaerobic Toluene Degradation via Sulfur Cycling in Marine Sediments

    PubMed Central

    Daghio, Matteo; Vaiopoulou, Eleni; Patil, Sunil A.; Suárez-Suárez, Ana; Head, Ian M.

    2015-01-01

    Hydrocarbons released during oil spills are persistent in marine sediments due to the absence of suitable electron acceptors below the oxic zone. Here, we investigated an alternative bioremediation strategy to remove toluene, a model monoaromatic hydrocarbon, using a bioanode. Bioelectrochemical reactors were inoculated with sediment collected from a hydrocarbon-contaminated marine site, and anodes were polarized at 0 mV and +300 mV (versus an Ag/AgCl [3 M KCl] reference electrode). The degradation of toluene was directly linked to current generation of up to 301 mA m−2 and 431 mA m−2 for the bioanodes polarized at 0 mV and +300 mV, respectively. Peak currents decreased over time even after periodic spiking with toluene. The monitoring of sulfate concentrations during bioelectrochemical experiments suggested that sulfur metabolism was involved in toluene degradation at bioanodes. 16S rRNA gene-based Illumina sequencing of the bulk anolyte and anode samples revealed enrichment with electrocatalytically active microorganisms, toluene degraders, and sulfate-reducing microorganisms. Quantitative PCR targeting the α-subunit of the dissimilatory sulfite reductase (encoded by dsrA) and the α-subunit of the benzylsuccinate synthase (encoded by bssA) confirmed these findings. In particular, members of the family Desulfobulbaceae were enriched concomitantly with current production and toluene degradation. Based on these observations, we propose two mechanisms for bioelectrochemical toluene degradation: (i) direct electron transfer to the anode and/or (ii) sulfide-mediated electron transfer. PMID:26497463

  18. Distribution of petroleum hydrocarbons and toluene biodegradation, Knox Street fire pits, Fort Bragg, North Carolina

    USGS Publications Warehouse

    Harden, S.L.; Landmeyer, J.E.

    1996-01-01

    An investigation was conducted at the Knox Street fire pits, Fort Bragg, North Carolina, to monitor the distribution of toluene, ethylbenzene, and xylene (TEX) in soil vapor, ground water, and ground-water/vapor to evaluate if total concentrations of TEX at the site are decreasing with time, and to quantify biodegradation rates of toluene in the unsaturated and saturated zones. Soil-vapor and ground-water samples were collected around the fire pits and ground-water/vapor samples were collected along the ground-water discharge zone, Beaver Creek, on a monthly basis from June 1994 through June 1995. Concentrations of TEX compounds in these samples were determined with a field gas chro- matograph. Laboratory experiments were performed on aquifer sediment samples to measure rates of toluene biodegradation by in situ micro- organisms. Based on field gas chromatographic analytical results, contamination levels of TEX compounds in both soil vapor and ground water appear to decrease downgradient of the fire-pit source area. During the 1-year study period, the observed temporal and spatial trends in soil vapor TEX concentrations appear to reflect differences in the distribution of TEX among solid, aqueous, and gaseous phases within fuel-contaminated soils in the unsaturated zone. Soil temperature and soil moisture are two important factors which influence the distribution of TEX com- pounds among the different phases. Because of the short period of data collection, it was not possible to distinguish between seasonal fluc- tuations in soil vapor TEX concentrations and an overall net decrease in TEX concentrations at the study site. No seasonal trend was observed in total TEX concentrations for ground- water samples collected at the study site. Although the analytical results could not be used to determine if ground-water TEX concen- trations decreased during the study at a specific location, the data were used to examine rate constants of toluene biodegradation. Based on

  19. Analysis of the gene cluster encoding toluene/o-xylene monooxygenase from Pseudomonas stutzeri OX1

    SciTech Connect

    Bertoni, G.; Martino, M.; Galli, E.; Barbieri, P.

    1998-10-01

    The toluene/o-xylene monooxygenase cloned from Pseudomonas stutzeri OX1 displays a very broad range of substrates and a very peculiar regioselectivity, because it is able to hydroxylate more than one position on the aromatic ring of several hydrocarbons and phenols. The nucleotide sequence of the gene cluster coding for this enzymatic system has been determined. The sequence analysis revealed the presence of six open reading frames (ORFs) homologous to other genes clustered in operons coding for multicomponent monooxygenases found in benzene- and toluene-degradative pathways cloned from Pseudomonas strains. Significant similarities were also found with multicomponent monooxygenase systems for phenol, methane, alkene, and dimethyl sulfide cloned from different bacterial strains. The knockout of each ORF and complementation with the wild-type allele indicated that all six ORFs are essential for the full activity of the toluene/o-xylene monooxygenase in Escherichia coli. This analysis also shows that despite its activity on both hydrocarbons and phenols, toluene/o-xylene monooxygenase belongs to a toluene multicomponent monooxygenase subfamily rather than to the monooxygenases active on phenols.

  20. Psychological Autopsy and Necropsy of an Unusual Case of Suicide by Intravenous Toluene

    PubMed Central

    Kulkarni, Ranganath R.; Hemanth Kumar, RG; Kulkarni, Pratibha R.; Kotabagi, Raghavendra B.

    2015-01-01

    Toluene (methylbenzene; volatile hydrocarbon) is an industrial solvent that causes major injury to the lungs; the organ being the first capillary bed encountered. We report an unusual case of suicide by a 24-year-old male, paramedical professional, with fatal outcome within 16 h of intentional, intravenous self-administration of toluene, with clinical presentation of acute respiratory distress syndrome. Psychological autopsy revealed severe depressive disorder and solvent (inhalant) abuse, with marital disharmony as the precipitating stressor for suicide. Necropsy revealed diffuse congestion of internal organs like lungs and liver, epicardial petechial hemorrhages, and gastric hemorrhages. Treatment of toluene poisoning includes supportive care as no specific antidote is available. Early and aggressive management may be conducive to a favorable outcome with minimal residual pulmonary sequelae. Relevant literature of toluene poisoning was identified via PubMed, PubChem, ToxNet, Hazardous Substances Data Bank (HSDB), Embase, and PsycINFO. To our knowledge, this is the first case of suicide by intravenous administration of toluene in the literature. PMID:25969615

  1. Oral intake of a toluene-containing thinner. Effects and headspace gas chromatographic analytical diagnosis.

    PubMed

    Zahlsen, K; Rygnestad, T; Nilsen, O G

    1985-01-01

    After an accidental oral intake of a paint thinner, the constituents were identified in stomach content using headspace gas chromatography. The composition indicated ingestion of a commonly used thinner containing 60-70% toluene, 20-25% n-butylacetate and 10-15% of ethanol. A toluene concentration of 22.0 mg/kg was measured in serum in contrast to n-butylacetate which was not detected. Ethanol concentration was 1.85 g/kg, most of this was due to ethanol ingestion before the intake of thinner. The half life of toluene in serum was 8.5 h initially, which increased to 14 h after 19 h. An effect on liver function was demonstrated by increased activity of serum transaminases. Compared with the upper normal limits ASAT and ALAT were increased by 6 and 2.5 times, respectively. For both parameters the highest activity was seen 40 hours after admission and normal levels were achieved after 7 days. It is concluded that toluene is readily absorbed by ingestion of toluene-containing thinners, and that the function of the human liver is transiently affected. For screening purposes gas chromatography proved to be a useful method for the analytical diagnosis in cases of organic solvent intoxication. The use of the headspace technique further improved the speed of analysis and eliminated contamination of the gas chromatographic system. PMID:3868371

  2. The desorption of toluene from a montmorillonite clay adsorbent in a rotary kiln environment

    SciTech Connect

    Owens, W.D.; Silcox, G.D.; Lighty, J.S.; Xiao Xue Deng; Pershing, D.W. ); Cundy, V.A.; Leger, C.B.; Jakway, A.L. )

    1992-05-01

    The vaporization of toluene from pre-dried, 3 mm montmorillonite clay particles was studied in a 130 kW pilot-scale rotary kiln with inside dimensions of 0.61 by 0.61 meters. Vaporization rates were obtained with a toluene weight fraction of 0.25 percent as a function of kiln fill fractions from 3 to 8 percent, rotation rates from 0.1 to 0.9 rpm, and kiln wall temperatures from 189 to 793 C. Toluene desorption rates were obtained from gas-phase measurements and interpreted using a desorption model that incorporates the slumping frequency of the solids, the fill fraction of the kiln, the diffusion of toluene in the bed, and the rate of particle desorption using an Arrhenius-type expression that is a function of bed temperature and average bed concentration. The model included three adjustable desorption parameters which were obtained by fitting the experimental data at one set of conditions with a least squares technique. Solid and kiln-wall temperatures were continuously recorded and used in the model at predicting the effects of fill fraction and rotation rate over a range of temperatures. A methodology for predicting full-scale performance was developed. Full-scale toluene desorption predictions were completed for different operating temperatures.

  3. Assessment of anaerobic toluene biodegradation activity by bssA transcript/gene ratios.

    PubMed

    Brow, Christina N; O'Brien Johnson, Reid; Johnson, Richard L; Simon, Holly M

    2013-09-01

    Benzylsuccinate synthase (bssA) genes associated with toluene degradation were profiled across a groundwater contaminant plume under nitrate-reducing conditions and were detected in significant numbers throughout the plume. However, differences between groundwater and core sediment samples suggested that microbial transport, rather than local activity, was the underlying cause of the high copy numbers within the downgradient plume. Both gene transcript and reactant concentrations were consistent with this hypothesis. Expression of bssA genes from denitrifying toluene degraders was induced by toluene but only in the presence of nitrate, and transcript abundance dropped rapidly following the removal of either toluene or nitrate. The drop in bssA transcripts following the removal of toluene could be described by an exponential decay function with a half-life on the order of 1 h. Interestingly, bssA transcripts never disappeared completely but were always detected at some level if either inducer was present. Therefore, the detection of transcripts alone may not be sufficient evidence for contaminant degradation. To avoid mistakenly associating basal-level gene expression with actively degrading microbial populations, an integrated approach using the ratio of functional gene transcripts to gene copies is recommended. This approach minimizes the impact of microbial transport on activity assessment and allows reliable assessments of microbial activity to be obtained from water samples. PMID:23811506

  4. Toluene degradation by Pseudomonas putida F1: genetic organization of the tod operon

    SciTech Connect

    Zylstra, G.J.; McCombie, W.R.; Gibson, D.T.; Finette, B.A.

    1988-06-01

    Pseudomonas putida PpF1 degrades toluene through cis-toluene dihydrodiol to 3-methylcatechol. The latter compound is metabolized through the well-established meta pathway for catechol degradation. The first four steps in the pathway involve the sequential action of toluene dioxygenase (todABC1C2), cis-toluene, dihydrodiol dehydrogenase (todD), 3-methylcatechol 2,3-dioxygenase (todE), and 2-hydroxy-6-oxo-2,4-heptadienoate hydrolase (todF). The genes for these enzymes form part of the tod operon which is responsible for the degradation of toluene by this organism. A combination of transposon mutagenesis of the PpF1 chromosome, was well as the analysis of cloned chromosomal fragments, was used to determine the physical order of the genes in the tod operon. The genes were determined to be transcribed in the order todF, todC1, todC2, todB, todA, todD, todE.

  5. PANI and Graphene/PANI Nanocomposite Films — Comparative Toluene Gas Sensing Behavior

    PubMed Central

    Parmar, Mitesh; Balamurugan, Chandran; Lee, Dong-Weon

    2013-01-01

    The present work discusses and compares the toluene sensing behavior of polyaniline (PANI) and graphene/polyaniline nanocomposite (C-PANI) films. The graphene–PANI ratio in the nanocomposite polymer film is optimized at 1:2. For this, N-methyl-2-pyrrolidone (NMP) solvent is used to prepare PANI-NMP solution as well as graphene-PANI-NMP solution. The films are later annealed at 230 °C, characterized using scanning electron microscopy (SEM) as well Fourier transform infrared spectroscopy (FTIR) and tested for their sensing behavior towards toluene. The sensing behaviors of the films are analyzed at different temperatures (30, 50 and 100 °C) for 100 ppm toluene in air. The nanocomposite C-PANI films have exhibited better overall toluene sensing behavior in terms of sensor response, response and recovery time as well as repeatability. Although the sensor response of PANI (12.6 at 30 °C, 38.4 at 100 °C) is comparatively higher than that of C-PANI (8.4 at 30 °C, 35.5 at 100 °C), response and recovery time of PANI and C-PANI varies with operating temperature. C-PANI at 50 °C seems to have better toluene sensing behavior in terms of response time and recovery time. PMID:24300600

  6. Specific bronchial reactivity to toluene diisocyanate: relationship with baseline clinical findings.

    PubMed Central

    Paggiaro, P L; Innocenti, A; Bacci, E; Rossi, O; Talini, D

    1986-01-01

    One hundred and fourteen subjects with asthma induced by toluene diisocyanate were identified and the pattern of their bronchial responses to challenge with toluene diisocyanate was studied. An occupational type specific bronchial provocation test with toluene diisocyanate (10-25 parts per thousand million for 10-15 minutes) elicited an immediate response in 24, a late response in 50, and a dual response in 40 patients. Subjects with a dual response showed at diagnosis a longer duration of symptoms and a greater prevalence of airway obstruction; in these subjects FEV1 (percentage of predicted value) was lower than in subjects with immediate or late reactions to toluene diisocyanate. The percentage of current smokers and ex-smokers was significantly lower in subjects with a late response (26%) than in subjects with immediate or dual responses (56% and 57% respectively). In 27 of the 114 subjects a non-specific challenge test with methacholine was performed and subjects with dual responses showed greater non-specific bronchial hyperresponsiveness than the other groups. These results suggest that a dual response to specific challenge in bronchial asthma related to toluene diisocyanate may be associated with more severe disease than other types of response, as assessed by duration of symptoms, baseline airway obstruction, and non-specific bronchial hyperresponsiveness. The high prevalence of non-smokers and low prevalence of smokers in the group with a late response to specific challenge is so far unexplained. PMID:3016938

  7. Theoretical study of deuterium kinetic isotope effect in peroxidation of phenol and toluene

    NASA Astrophysics Data System (ADS)

    Luzhkov, Victor B.

    2005-12-01

    Reaction mechanisms of hydrogen abstraction from phenol and toluene by the hydroperoxyl radical are probed by theoretical calculations of deuterium kinetic isotope effect (KIE). In experiment the given free-radical reactions have nearly equal reaction heats and rates differing by 6 orders of magnitudes, yet demonstrate high H/D KIEs. The mechanism of phenol-peroxyl reaction is described by the proton-coupled electron transfer (PCET), while the toluene-peroxyl reaction follows the non-polar H-atom transfer (HAT). In present work, the H/D KIEs are assessed for several isotopomers of phenol and toluene using the DFT B3LYP/6-311+G(2d,2p) calculations and the post-processing Bigeleisen treatment with one-dimensional tunnel corrections. Differing patterns of bending vibrations are noted for the PCET and HAT TSs considered. The computed KIEs are 10.7 and 17.0 (at 65 °C) for the phenol and toluene reactions, respectively, that agrees with the available experimental results. The corresponding semi-classical contributions are 4.5 and 5.1, whereas the tunnel correction computed for unsymmetrical Eckart function yields the factors of 2.4 and 3.3 for phenol and toluene, respectively. The advantage of using Bigeleisen formula for reaction intermediates with low-frequency internal rotation modes is discussed.

  8. Effect of Water Vapor on Toluene Removal in Catalysis-DBD Plasma Reactors

    NASA Astrophysics Data System (ADS)

    Wang, Jingting; Cao, Xu; Zhang, Renxi; Gong, Ting; Hou, Huiqi; Chen, Shanping; Zhang, Ruina

    2016-04-01

    The experiment was carried out in a cylindrical dielectric barrier discharge (DBD) reactor assisted with a catalyst to decompose toluene under different humidity. In order to explore the synergistic effect on removing toluene in the catalysis-DBD reactor, this paper investigated the decomposition efficiency and the energy consumption in the catalysis-DBD and the non-catalyst DBD reactors under different humidity. The results showed that the catalysis-DBD reactor had a better performance than the non-catalysis one at the humidity ratio of 0.4%, and the removal efficiency of toluene could reach 88.6% in the catalysis-DBD reactor, while it was only 59.9% in the non-catalytic reactor. However, there was no significant difference in the removal efficiency of toluene between the two reactors when the humidities were 1.2% and 2.4%. Additionally, the degradation products were also analyzed in order to gain a better understanding of the mechanism of decomposing toluene in a catalysis-DBD reactor. supported by the Key Project which is sponsored by the Science and Technology Commission of Shanghai Municipality (No. 13231201903), the Key Programs for Science and Technology Development sponsored by the Science and Technology Commission of Shanghai Municipality (Nos. 13231201901 and 14DZ1208401), and the Key Project sponsored by the State-owned Assets Supervision and Administration Commission of Shanghai, China (No. 2013019)

  9. Occupational Health Risks Among Trichloroethylene-Exposed Workers in a Clock Manufacturing Factory

    PubMed Central

    Singthong, Siriporn; Pakkong, Pannee; Choosang, Kantima; Wongsanit, Sarinya

    2015-01-01

    Trichloroethylene (TCE) is an important volatile organic compound once widely used in industry throughout the world. Occupational exposure to TCE can cause a number of health hazards such as allergic reactions and genetic damage. The purpose of this study was to evaluate occupational exposure to TCE, by analysis of the air in the breathing zone and of urine from workers employed in a clock manufacturing factory. A subjective symptom survey was conducted by using a self-administered questionnaire to evaluate the health hazards. Micronucleus (MN) frequency, based on the cytokinesis-block micronucleus assay (CBMN) in peripheral blood lymphocytes, (PBLs) was used as a biomarker for chromosome damage. A total of 244 participants, including 171 workers occupationally exposed to TCE and 73 non-exposed control employees, working mainly in office jobs in the same factory, were enrolled in this study. Analyses of airborne TCE concentrations in the workplace, and of urinary trichloroacetic acid (TCA) of the workers and controls, were performed by Gas Chromatography-Electron Capture Detector (GC-ECD) using the modified headspace technique. The average concentration of TCE in the workplace breathing zone was 27.83 ± 6.02 ppm. The average level of urinary TCA of the exposed workers and controls was 14.84 ± 1.62, 2.95 ± 0.28 mg/L. The frequency of MN/1000BN was 7.029 ± 0.39, significantly higher than for those in the control group (3.57 ± 0.31, p = 0.001). According to multiple linear regression analysis, the results indicated that urinary TCA levels correlated with the increased MN in exposed workers (r = 0.285, p < 0.001). The prevalence rate of subjective symptoms in the exposed group was 9.61-11.76 times higher than the rate of the non-exposed group (p < 0.001). It was found that skin (29.6%) and respiratory symptoms (21.1%) were the most frequent among the exposed workers. In conclusion, these results indicate that increased micronucleus frequency is associated with

  10. Occupational health risks among trichloroethylene-exposed workers in a clock manufacturing factory.

    PubMed

    Singthong, Siriporn; Pakkong, Pannee; Choosang, Kantima; Wongsanit, Sarinya

    2015-01-01

    Trichloroethylene (TCE) is an important volatile organic compound once widely used in industry throughout the world. Occupational exposure to TCE can cause a number of health hazards such as allergic reactions and genetic damage. The purpose of this study was to evaluate occupational exposure to TCE, by analysis of the air in the breathing zone and of urine from workers employed in a clock manufacturing factory. A subjective symptom survey was conducted by using a self-administered questionnaire to evaluate the health hazards. Micronucleus (MN) frequency, based on the cytokinesis-block micronucleus assay (CBMN) in peripheral blood lymphocytes, (PBLs) was used as a biomarker for chromosome damage. A total of 244 participants, including 171 workers occupationally exposed to TCE and 73 non-exposed control employees, working mainly in office jobs in the same factory, were enrolled in this study. Analyses of airborne TCE concentrations in the workplace, and of urinary trichloroacetic acid (TCA) of the workers and controls, were performed by Gas Chromatography-Electron Capture Detector (GC-ECD) using the modified headspace technique. The average concentration of TCE in the workplace breathing zone was 27.83 ± 6.02 ppm. The average level of urinary TCA of the exposed workers and controls was 14.84 ± 1.62, 2.95 ± 0.28 mg/L. The frequency of MN/1000BN was 7.029 ± 0.39, significantly higher than for those in the control group (3.57 ± 0.31, p = 0.001). According to multiple linear regression analysis, the results indicated that urinary TCA levels correlated with the increased MN in exposed workers (r = 0.285, p < 0.001). The prevalence rate of subjective symptoms in the exposed group was 9.61-11.76 times higher than the rate of the non-exposed group (p < 0.001). It was found that skin (29.6%) and respiratory symptoms (21.1%) were the most frequent among the exposed workers. In conclusion, these results indicate that increased micronucleus frequency is associated with

  11. Probing Toluene and Ethylbenzene Stable Glass Formation using Inert Gas Permeation

    SciTech Connect

    Smith, R. Scott; May, Robert A.; Kay, Bruce D.

    2015-09-01

    Inert gas permeation is used to investigate the formation of stable glasses of toluene and ethylbenzene. The effect of deposition temperature (Tdep) on the kinetic stability of the vapor deposited glasses is determined using Kr desorption spectra from within sandwich layers of either toluene or ethylbenzene. The results for toluene show that the most stable glass is formed at Tdep = 0.92 Tg, although glasses with a kinetic stability within 50% of the most stable glass were found with deposition temperatures from 0.85 to 0.95 Tg. Similar results were found for ethylbenzene, which formed its most stable glass at 0.91 Tg and formed stable glasses from 0.81 to 0.96 Tg. These results are consistent with recent calorimetric studies and demonstrate that the inert gas permeation technique provides a direct method to observe the onset of molecular translation motion that accompanies the glass to supercooled liquid transition.

  12. Electrophilic and free radical nitration of benzene and toluene with various nitrating agents*

    PubMed Central

    Olah, George A.; Lin, Henry C.; Olah, Judith A.; Narang, Subhash C.

    1978-01-01

    Electrophilic nitration of toluene and benzene was studied under various conditions with several nitrating systems. It was found that high orthopara regioselectivity is prevalent in all reactions and is independent of the reactivity of the nitrating agent. The methyl group of toluene is predominantly ortho-para directing under all reaction conditions. Steric factors are considered to be important but not the sole reason for the variation in the ortho/para ratio. The results reinforce our earlier views that, in electrophilic aromatic nitrations with reactive nitrating agents, substrate and positional selectivities are determined in two separate steps. The first step involves a π-aromatic-NO2+ ion complex or encounter pair, whereas the subsequent step is of arenium ion nature (separate for the ortho, meta, and para positions). The former determines substrate selectivity, whereas the latter determines regioselectivity. Thermal free radical nitration of benzene and toluene with tetranitromethane in sharp contrast gave nearly statistical product distributions. PMID:16592503

  13. A novel toluene sensor based on ZnO-SnO 2 nanofiber web

    NASA Astrophysics Data System (ADS)

    Song, Xiaofeng; Zhang, Dejiang; Fan, Meng

    2009-05-01

    We proposed in the present work that large-scale synthesis of sensitive ZnO-SnO 2 nanofibres which can be obtained via a simple electrospinning method. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction patterns (XRD) showed the average diameter of ZnO-SnO 2 nanofibres ranging between 100 and 200 nm, the mixture of wurtzite (ZnO) and rutile (SnO 2) structure in the composite fibers. The sensitivity of the obtained ZnO-SnO 2 nanofibres to toluene was also investigated. The results showed that under optimal conditions, the calibration curve of response versus toluene concentration was linear in the range of 10-300 ppm, the response and recovery time were only several seconds, and sensitivity for toluene was desirable.

  14. Investigation of the role of bicyclic peroxy radicals in the oxidation mechanism of toluene.

    PubMed

    Birdsall, Adam W; Andreoni, John F; Elrod, Matthew J

    2010-10-01

    The products of the primary OH-initiated oxidation of toluene were investigated using the turbulent flow chemical ionization mass spectrometry technique under different oxygen, NO, and initial OH radical concentrations as well as a range of total pressures. The bicyclic peroxy radical intermediate, a key proposed intermediate species in the Master Chemical Mechanism (MCM) for the atmospheric oxidation of toluene, was detected for the first time. The toluene oxidation mechanism was shown to have a strong oxygen concentration dependence, presumably due to the central role of the bicyclic peroxy radical in determining the stable product distribution at atmospheric oxygen concentrations. The results also suggest a potential role for bicyclic peroxy radical + HO(2) reactions at high HO(2)/NO ratios. These reactions are postulated to be a source of the inconsistencies between environmental chamber results and predictions from the MCM. PMID:20836528

  15. Non-invasive toluene sensor for early diagnosis of lung cancer

    NASA Astrophysics Data System (ADS)

    Saxena, Rahul; Srivastava, Sudha

    2016-04-01

    Here we present, quantification of volatile organic compounds in human breath for early detection of lung cancer to increase survival probability. Graphene oxide nanosheets synthesized by modified Hummer's method were employed as a sensing element to detect the presence of toluene in the sample. Optical and morphological characterization of synthesized nanomaterial was performed by UV-Visible spectroscopy and scanning electron microscopy (SEM) respectively. Spectroscopic assay shows a linearly decreasing intensity of GO absorption peak with increasing toluene concentration with a linear range from 0-200 pM. While impedimetric sensor developed on a graphene oxide nanosheetsmodified screen printed electrodes displayed a decreasing electron transfer resistance increasing toluene with much larger linear range of 0-1000 pM. Reported techniques are advantageous as these are simple, sensitive and cost effective, which can easily be extended for primary screening of other VOCs.

  16. Ignition delay times of benzene and toluene with oxygen in argon mixtures

    NASA Technical Reports Server (NTRS)

    Burcat, A.; Snyder, C.; Brabbs, T.

    1985-01-01

    The ignition delay times of benzene and toluene with oxygen diluted in argon were investigated over a wide range of conditions. For benzene the concentration ranges were 0.42 to 1.69 percent fuel and 3.78 to 20.3 percent oxygen. The temperature range was 1212 to 1748 K and the reflected shock pressures were 1.7 to 7.89 atm. Statistical evaluation of the benzene experiments provided an overall equation which is given. For toluene the concentration ranges were 0.5 to 1.5 percent fuel and 4.48 to 13.45 percent oxygen. The temperature range was 1339 to 1797 K and the reflected shock pressures were 1.95 to 8.85 atm. The overall ignition delay equation for toluene after a statistical evaluation is also given. Detailed experimental information is provided.

  17. Toluene oxidation by non-thermal plasma combined with palladium catalysts.

    PubMed

    Magureanu, Monica; Dobrin, Daniela; Mandache, Nicolae B; Cojocaru, Bogdan; Parvulescu, Vasile I

    2013-01-01

    The oxidation of toluene in air was investigated using a dielectric barrier discharge (DBD) combined with a Pd/Al2O3 catalyst. When using only plasma, rather low selectivity toward CO2 was obtained: 32-35%. By filling the DBD reactor with Pd/Al2O3 catalyst the CO2 selectivity was significantly enhanced (80-90%), however, a large amount of toluene was desorbed from the catalyst when the discharge was operated. By filling a quarter of the discharge gap with catalyst and placing the rest of the catalyst downstream of the plasma reactor, an important increase of CO2 selectivity (~75%) and a 15% increase in toluene conversion were achieved as compared to the results with plasma alone. The catalyst exhibited a very good stability in this reaction. PMID:24790936

  18. Trichloroethylene degradation using recombinant bacteria expressing the soluble methane monooxygenase from methylosinus trichosporium OB3b

    SciTech Connect

    Jahng, D.; Kim, C.; Wood, T.K.

    1995-12-01

    Soluble methane monooxygenase (sMMO) from M. trichosporium OB3b has the ability to degrade many halogenated aliphatic compounds that are found in contaminated soil and groundwater. For efficient trichloroethylene (TCE) degradation in a foreign host, efforts are being made to improve inconsistent and low sMMO activity of the recombinant strain constructed previously (Pseudomonas putida F1/pSMMO20). Additional smmo-containing recombinant strains have been constructed including various Pseudomonas, Agrobacterium, and Rhizobium strains. Recombinant facultative methylotrophs containing the smmo locus were also constructed through electroporation and tri-parental mating using a new plasmid pSMMO50. TCE degradation by these recombinant strains was examined. The effect of metal ions on in vitro sMMO activity was also discerned to optimize the expression medium. Among the metal ions examined, Cu(I), Cu(II), Ni(II), and Zn(II) inhibited sMMO purified from trichosporium OB3b, and the effect of the metal ions on each of the components of sMMO will also be discussed. In addition, the post-segregational killing locus (hok/sok) from E. coli plasmid R1 was inserted downstream of the smmo locus to stabilize the recombinant plasmid in these host cells, and chemostat cultures were used to optimize expression of active sMMO by varying the growth rate.

  19. Effect of phosphate and sediment bacteria on trichloroethylene dechlorination with zero valent iron.

    PubMed

    Min, Jee-Eun; Park, In Sun; Ko, Seokoh; Shin, Won Sik; Park, Jae-Woo

    2009-03-01

    The effects of sediment-isolated bacteria and phosphate on the efficacy of zero valent iron (ZVI) for the dechlorination of trichloroethylene (TCE) were examined in batch experiments. TCE (0.3 mM) and a constant concentration of sediment bacteria were simultaneously exposed to ZVI in the presence of 0 mmol, 15 mmol, and 30 mmol of phosphate. TCE profiles, starting from 0.3 mM to about 0.1 mM, exhibited two-phase of sorption kinetics at all three phosphate concentrations without the sediment bacteria. TCE removal was less and slower with phosphate in the system. With the sediment bacteria, however, more TCE was removed with the sediment bacteria than without it, unlike our initial hypothesis. With the sediment bacteria and phosphate, the concentration of ferrous (0.505 mM) ions was doubled that with phosphate only (0.271 mM). The sediment bacteria in this research, mainly Bacillus sp., could contribute to the long-term stability of ZVI reactivity for dechlorination of TCE in sediment. The sediment bacteria in this research could reduce the iron or chelate the evolved ferrous ions to retain the reducing reactivity of ZVI. PMID:19184703

  20. Historical Occupational Trichloroethylene Air Concentrations Based on Inspection Measurements From Shanghai, China

    PubMed Central

    Friesen, Melissa C.; Locke, Sarah J.; Chen, Yu-Cheng; Coble, Joseph B.; Stewart, Patricia A.; Ji, Bu-Tian; Bassig, Bryan; Lu, Wei; Xue, Shouzheng; Chow, Wong-Ho; Lan, Qing; Purdue, Mark P.; Rothman, Nathaniel; Vermeulen, Roel

    2015-01-01

    Purpose: Trichloroethylene (TCE) is a carcinogen that has been linked to kidney cancer and possibly other cancer sites including non-Hodgkin lymphoma. Its use in China has increased since the early 1990s with China’s growing metal, electronic, and telecommunications industries. We examined historical occupational TCE air concentration patterns in a database of TCE inspection measurements collected in Shanghai, China to identify temporal trends and broad contrasts among occupations and industries. Methods: Using a database of 932 short-term, area TCE air inspection measurements collected in Shanghai worksites from 1968 through 2000 (median year 1986), we developed mixed-effects models to evaluate job-, industry-, and time-specific TCE air concentrations. Results: Models of TCE air concentrations from Shanghai work sites predicted that exposures decreased 5–10% per year between 1968 and 2000. Measurements collected near launderers and dry cleaners had the highest predicted geometric means (GM for 1986 = 150–190mg m−3). The majority (53%) of the measurements were collected in metal treatment jobs. In a model restricted to measurements in metal treatment jobs, predicted GMs for 1986 varied 35-fold across industries, from 11mg m−3 in ‘other metal products/repair’ industries to 390mg m–3 in ‘ships/aircrafts’ industries. Conclusions: TCE workplace air concentrations appeared to have dropped over time in Shanghai, China between 1968 and 2000. Understanding differences in TCE concentrations across time, occupations, and industries may assist future epidemiologic studies in China. PMID:25180291

  1. Degradation of Trichloroethylene and Dichlorobiphenyls by Iron-Based Bimetallic Nanoparticles

    PubMed Central

    Tee, Yit-Hong; Bachas, Leonidas; Bhattacharyya, Dibakar

    2009-01-01

    Bimetallic nanoparticles of Ni/Fe and Pd/Fe were used to study the degradation of trichloroethylene (TCE) at room temperature. The activity for different iron-based nanoparticles with nickel as the catalytic dopant was analyzed using iron mass-normalized hydrogen generation rate. Degradation kinetics in terms of surface area-normalized rate constant was observed to have a strong correlation with the hydrogen generated by iron oxidation. A sorption study was conducted, and a mathematical model was derived that incorporates the reaction and Langmuirian-type sorption terms to estimate the intrinsic rate constant and rate-limiting step in the degradation process, assuming negligible mass transfer resistance of TCE to the solid particles phase. A longevity study through repeated cycle experiments was conducted to analyze the effect of activity loss on the reaction mechanistic pathway, and the results showed that the attenuation in the nanoparticles activity did not adversely affect the reaction mechanisms in generating gaseous products such as ethylene and ethane. PMID:20161161

  2. Bioremediation of Trichloroethylene-Contaminated Sediments Augmented with a Dehalococcoides Consortia

    SciTech Connect

    McKinsey, P.C.

    2003-02-20

    At the Department of Energy's (DOE) Savannah River Site (SRS) in Aiken, SC there are a number of sites contaminated with Chlorinated Ethenes (CE) due to past disposal practices. Sediments from two CE contaminated SRS locations were evaluated for trichloroethylene (TCE) biodegradation through anaerobic laboratory microcosms. The testing included addition of amendments and bioaugmentation of sediments. The anaerobic microcosms were first amended with substrates including acetate, lactate, molasses, soybean oil, methanol, sulfate, yeast extract, Regenesis HRC(R), and MEAL (methanol, ethanol, acetate, lactate mixture). Microcosms were analyzed after biostimulation for 9 months and no significant TCE biodegradation was observed. At 10 months, additional TCE, fresh amendments, and a mixed culture containing Dehalococcoides ethenogenes were added to active microcosms. A significant decrease in TCE concentrations and an increase in biodegradation products cis-dichloroethylene (cDCE) and vinyl chloride (VC) were noted within 2 weeks of bioaugmentation. Microcosms amended with lactate and sulfate showed complete transformation of TCE (3 ppm) to ethene within 40 days after bioaugmentation. Microcosms amended with other substrates - soybean oil, acetate, yeast extract, and methanol - also show enhanced biodegradation of TCE to ethene. Microcosms amended with molasses and Regenesis HRC showed limited TCE transformation. No TCE transformation was seen in killed control microcosms. On the basis of these successful results, plans are underway for field-scale in-situ deployment of biostimulation/bioaugmentation at SRS.

  3. Electrochemical transformation of trichloroethylene in aqueous solution by electrode polarity reversal.

    PubMed

    Rajic, Ljiljana; Fallahpour, Noushin; Yuan, Songhu; Alshawabkeh, Akram N

    2014-12-15

    Electrode polarity reversal is evaluated for electrochemical transformation of trichloroethylene (TCE) in aqueous solution using flow-through reactors with mixed metal oxide electrodes and Pd catalyst. The study tests the hypothesis that optimizing electrode polarity reversal will generate H2O2 in Pd presence in the system. The effect of polarity reversal frequency, duration of the polarity reversal intervals, current intensity and TCE concentration on TCE removal rate and removal mechanism were evaluated. TCE removal efficiencies under 6 cycles h(-1) were similar in the presence of Pd catalyst (50.3%) and without Pd catalyst (49.8%), indicating that Pd has limited impact on TCE degradation under these conditions. The overall removal efficacies after 60 min treatment under polarity reversal frequencies of 6, 10, 15, 30 and 90 cycles h(-1) were 50.3%, 56.3%, 69.3%, 34.7% and 23.4%, respectively. Increasing the frequency of polarity reversal increases TCE removal as long as sufficient charge is produced during each cycle for the reaction at the electrode. Electrode polarity reversal shifts oxidation/reduction and reduction/oxidation sequences in the system. The optimized polarity reversal frequency (15 cycles h(-1) at 60 mA) enables two reaction zones formation where reduction/oxidation occurs at each electrode surface. PMID:25282093

  4. In situ bioremediation of trichloroethylene-contaminated water by a resting-cell methanotrophic microbial filter

    SciTech Connect

    Taylor, R T; Duba, A G; Durham, W B; Hanna, M L; Jackson, K J; Jovanovich, M C; Knapp, R B; Knezovich, J P; Shah, N N; Shonnard, D R; Wijesinghe, A M

    1992-10-01

    The Lawrence Livermore National Laboratory is testing and developing an in situ microbial filter technology for remediating migrating subsurface plumes contaminated with low concentrations of trichloroethylene (TCE). Their current focus is the establishment of a replenishable bioactive zone (catalytic filter) along expanding plume boundaries by the Injection of a representative methanotrophic bacterium, Methylosinus trichosporium OB3b. We have successfully demonstrated this microbial filter strategy using emplaced, attached resting cells (no methane additions) in a 1.1-m flow-through test bed loaded with water-saturated sand. Two separate 24 h pulses of TCE (109 ppb and 85 ppb), one week apart, were pumped through the system at a flow velocity of 1.5 cm/h; no TCE (<0.5 ppb) was detected on the downstream side of the microbial filter. Subsequent excavation of the wet sand confirmed the existence of a TCE-bioactive zone 19 days after it had been created. An enhanced longevity of the cellular, soluble-form methane monooxygenase produced by this methanotroph Is a result of our laboratory bioreactor culturing conditions. Additional experiments with cells in sealed vials and emplaced in the 1.1-m test bed yielded a high resting-cell finite TCE biotransformation capacity of [approximately] 0.25 mg per mg of bacteria; this is suitable for a planned sand-filled trench field demonstration at a Lawrence Livermore National Laboratory site.

  5. Evaluation of the effectiveness of using alfalfa and buffalo grass for remediation of trichloroethylene from groundwater

    SciTech Connect

    Caravello, V.

    1998-06-03

    Phytoremediation is receiving increasing attention due to the potential for vegetation to play a significant role in bioremediation of contaminated soils and groundwater. The purpose of this research was to conduct a pilot study to determine if buffalo grass would enhance the remediation of groundwater contaminated with trichloroethylene (TCE). A mass-balance experiment was designed and executed to determine the extent of TCE remediation/degradation occurring through buffalo grass. Measurements for TCE in air, water, and soil were completed for three treatments: (1) buffalo grass, (2) alfalfa, and (3) soil following challenge with a water-TCE mixture. In total, 267 air samples, 43 water samples, 85 soil samples, and 40 vegetative samples were collected and analyzed. The analysis identified two important facts. First, there were no significant differences detected between TCE concentrations in soil, water, and air between groups. Second, there is a significant difference in the amount of the TCE-water mixture consumed in chambers with plants versus chambers without plants. The mass balance of the experiment was not achieved due to unaccountable losses of TCE from the chambers. The major loss mechanism for TCE appears to be from the breakthrough of air sampling media during the experiment. Thus, the data are insufficient to determine if remediation occurred via plants or by preferential pathways through the soil. Future experiments should be designed to include daily monitoring of the aquifer, humidity tolerant air sampling protocol, and relief from the build-up of humidity and transpiration inside the chambers.

  6. Redox control for electrochemical dechlorination of trichloroethylene in bicarbonate aqueous media

    PubMed Central

    Mao, Xuhui; Ciblak, Ali; Amiri, Mohammad; Alshawabkeh, Akram N.

    2011-01-01

    The role of iron anode on electrochemical dechlorination of aqueous trichloroethylene (TCE) is evaluated using batch mixed-electrolyte experiments. A significantly higher dechlorination rate, up to 99%, is reported when iron anode and copper foam cathodes are used. In contrast to the oxygen-releasing inert anode, the cast iron anode generates ferrous species, which regulate the electrolyte to a reducing condition (low ORP value) and favor the reduction of TCE. The main products of TCE electrochemical reduction on copper foam cathode include ethene and ethane. The ratio of these two hydrocarbons gases varied with the electrolyte ORP condition and current density as more ethane gas generates at more reducing electrolyte condition and at higher current condition. A pseudo-first order model is used to describe the degradation of TCE, the first order rate constant (k) increased with the current applied, but exhibits a negative relation with initial concentration. Depending on the current, electrolysis by iron anode causes a reduction in the ORP and an increase in the pH of the mixed electrolyte. Enhanced reaction rates in this investigation indicate that the electrochemical reduction using copper foam and iron anode may be a promising process for remediation of groundwater contaminated with chlorinated organic compounds. PMID:21671641

  7. Trichloroethylene exposure aggravates behavioral abnormalities in mice that are deficient in superoxide dismutase.

    PubMed

    Otsuki, Noriyuki; Homma, Takujiro; Fujiwara, Hiroki; Kaneko, Kenya; Hozumi, Yasukazu; Shichiri, Mototada; Takashima, Mizuki; Ito, Junitsu; Konno, Tasuku; Kurahashi, Toshihiro; Yoshida, Yasukazu; Goto, Kaoru; Fujii, Satoshi; Fujii, Junichi

    2016-08-01

    Trichloroethylene (TCE) has been implicated as a causative agent for Parkinson's disease (PD). The administration of TCE to rodents induces neurotoxicity associated with dopaminergic neuron death, and evidence suggests that oxidative stress as a major player in the progression of PD. Here we report on TCE-induced behavioral abnormality in mice that are deficient in superoxide dismutase 1 (SOD1). Wild-type (WT) and SOD1-deficient (Sod1(-/-)) mice were intraperitoneally administered TCE (500 mg/kg) over a period of 4 weeks. Although the TCE-administrated Sod1(-/-) mice showed marked abnormal motor behavior, no significant differences were observed among the experimental groups by biochemical and histopathological analyses. However, treating mouse neuroblastoma-derived NB2a cells with TCE resulted in the down regulation of the SOD1 protein and elevated oxidative stress under conditions where SOD1 production was suppressed. Taken together, these data indicate that SOD1 plays a pivotal role in protecting motor neuron function against TCE toxicity. PMID:27166294

  8. Remediation of trichloroethylene-contaminated groundwater by three modifier-coated microscale zero-valent iron.

    PubMed

    Han, Jun; Xin, Jia; Zheng, Xilai; Kolditz, Olaf; Shao, Haibing

    2016-07-01

    Building a microscale zero-valent iron (mZVI) reaction zone is a promising in situ remediation technology for restoring groundwater contaminated by trichloroethylene (TCE). In order to determine a suitable modifier that could not only overcome gravity sedimentation of mZVI but also improve its remediation efficiency for TCE, the three biopolymers xanthan gum (XG), guargum (GG), and carboxymethyl cellulose (CMC) were employed to coat mZVI for surface modification. The suspension stability of the modified mZVI and its TCE removal efficiency were systematically investigated. The result indicated that XG as a shear-thinning fluid showed the most remarkable efficiency of preventing mZVI from gravity sedimentation and enhancing the TCE removal efficiency by mZVI. In a 480-h experiment, the presence of XG (3 g L(-1)) increased the TCE removal efficiency by 31.85 %, whereas GG (3 g L(-1)) and CMC (3 g L(-1)) merely increased by 15.61 and 9.69 % respectively. The pH value, Eh value, and concentration of ferrous ion as functions of the reaction time were recorded in all the reaction systems, which indicated that XG worked best in buffering the pH value of the solution and inhibiting surface passivation of mZVI. PMID:27068901

  9. Influence of soil properties on vapor-phase sorption of trichloroethylene.

    PubMed

    Bekele, Dawit N; Naidu, Ravi; Chadalavada, Sreenivasulu

    2016-04-01

    Current practices in health risk assessment from vapor intrusion (VI) using mathematical models are based on assumptions that the subsurface sorption equilibrium is attained. The time required for sorption to reach near-steady-state conditions at sites may take months or years to achieve. This study investigated the vapor phase attenuation of trichloroethylene (TCE) in five soils varying widely in clay and organic matter content using repacked columns. The primary indicators of TCE sorption were vapor retardation rate (Rt), the time required for the TCE vapor to pass through the soil column, and specific volume of retention (VR), and total volume of TCE retained in soil. Results show TCE vapor retardation is mainly due to the rapid partitioning of the compound to SOM. However, the specific volume of retention of clayey soils with secondary mineral particles was higher. Linear regression analyses of the SOM and clay fraction with VR show that a unit increase in clay fraction results in higher sorption of TCE (VR) than the SOM. However, partitioning of TCE vapor was not consistent with the samples' surface areas but was mainly a function of the type of secondary minerals present in soils. PMID:26686522

  10. Co-adsorption of Trichloroethylene and Arsenate by Iron-Impregnated Granular Activated Carbon.

    PubMed

    Deng, Baolin; Kim, Eun-Sik

    2016-05-01

    Co-adsorption of trichloroethylene (TCE) and arsenate [As(V)] was investigated using modified granular activated carbons (GAC): untreated, sodium hypochlorite-treated (NaClO-GAC), and NaClO with iron-treated GAC (NaClO/Fe-GAC). Batch experiments of single- [TCE or As(V)] and binary- [TCE and As(V)] components solutions are evaluated through Langmuir and Freundlich isotherm models and adsorption kinetic tests. In the single-component system, the adsorption capacity of As(V) was increased by the NaClO-GAC and the NaClO/Fe-GAC. The untreated GAC showed a low adsorption capacity for As(V). Adsorption of TCE by the NaClO/Fe-GAC was maximized, with an increased Freundlich constant. Removal of TCE in the binary-component system was decreased 15% by the untreated GAC, and NaClO- and NaClO/Fe-GAC showed similar efficiency to the single-component system because of the different chemical status of the GAC surfaces. Results of the adsorption isotherms of As(V) in the binary-component system were similar to adsorption isotherms of the single-component system. The adsorption affinities of single- and binary-component systems corresponded with electron transfer, competitive adsorption, and physicochemical properties. PMID:27131303

  11. Evaluation of trichloroethylene degradation by starch supported Fe/Ni nanoparticles via response surface methodology.

    PubMed

    Nikroo, Razieh; Alemzadeh, Iran; Vossoughi, Manouchehr; Haddadian, Kamran

    2016-01-01

    In this study, degradation of trichloroethylene (TCE), a chlorinated hydrocarbon, using starch supported Fe/Ni nanoparticles was investigated. The scanning electron microscope images showed applying water soluble starch as a stabilizer for the Fe/Ni nanoparticles tended to reduce agglomeration and discrete particle. Also the mean particle diameter reduced from about 70 nm (unsupported Fe/Ni nanoparticle) to about 30 nm. Effects of three key independent operating parameters including initial TCE concentration (10.0-300.0 mg L(-1)), initial pH (4.00-10.00) and Fe(0) dosage (0.10-2.00) g L(-1) on TCE dechlorination efficiency in 1 hour were analysed by employing response surface methodology (RSM). Based on a five-level three-factor central composite design, TCE removal efficiency was examined and optimized. The obtained RSM model fitted the experimental data to a second order polynomial equation. The optimum dechlorination conditions at initial TCE concentration 100.0 mg L(-1) were initial pH 5.77, Fe(0) dosage 1.67 g L(-1). At these conditions TCE removal concentration reached 94.87%, which is in close acceptance with predicted value by the RSM model. PMID:26901738

  12. Application of calcium peroxide activated with Fe(II)-EDDS complex in trichloroethylene degradation.

    PubMed

    Zhang, Xiang; Gu, Xiaogang; Lu, Shuguang; Miao, Zhouwei; Xu, Minhui; Fu, Xiaori; Qiu, Zhaofu; Sui, Qian

    2016-10-01

    This study was conducted to assess the application of calcium peroxide (CP) activated with Fe(II) chelated by (S,S)-ethylenediamine-N,N'-disuccinic acid (EDDS) to enhance trichloroethylene (TCE) degradation in aqueous solution. It was indicated that EDDS prevented soluble iron from precipitation, and the optimum molar ratio of Fe(II)/EDDS to accelerate TCE degradation was 1/1. The influences of initial TCE, CP and Fe(II)-EDDS concentration were also investigated. The combination of CP and Fe(II)-EDDS complex rendered the efficient degradation of TCE at near neutral pH range. Chemical probe and scavenger tests identified that TCE degradation mainly owed to the oxidation of HO while O2(-) promoted HO generation. Cl(-), HCO3(-) and humic acid were found to inhibit CP/Fe(II)-EDDS performance on different levels. In conclusion, the application of CP activated with Fe(II)-EDDS complex is a promising technology in chemical remediation of groundwater, while further research in practical implementation is needed. PMID:27351899

  13. Removal of trichloroethylene by zerovalent iron/activated carbon derived from agricultural wastes.

    PubMed

    Su, Yuh-fan; Cheng, Yu-ling; Shih, Yang-hsin

    2013-11-15

    Activated carbon (AC) and zerovalent iron (ZVI) have been widely used in the adsorption and dehalogenation process, respectively, for the removal of organic compounds in environmental treatments. This study aims to prepare ZVI/AC derived from an agricultural waste, coir pith, through simple one-step pyrolysis. The effect of activation temperature and time on the surface area, iron content, and zerovalent iron ratio of ZVI/AC was systemically investigated. The results indicated that the activation of AC by FeSO4 significantly increased surface area of AC and distributed elemental iron over the AC. The X-ray diffraction (XRD), electron spectroscopy for chemical analysis (ESCA), and X-ray absorption near edge structure (XANES) spectra of ZVI/AC revealed that zerovalent iron was present. As compared to AC without FeSO4 activation, ZVI/AC increased the trichloroethylene removal rate constant by 7 times. The dechlorination ability of ZVI/AC was dominated by the zerovalent iron content. We have shown that lab-made ZVI/AC from coir pith can effectively adsorb and dehalogenate the chlorinated compounds in water. PMID:23994578

  14. Control of trichloroethylene plume migration using a biobarrier system: a field-scale study.

    PubMed

    Kuo, Y C; Wang, S Y; Chang, Y M; Chen, S H; Kao, C M

    2014-01-01

    The objective of this field-scale study was to evaluate the effectiveness of controlling trichloroethylene (TCE) plume migration using the polycolloid substrate (PS) biobarrier. The developed PS (containing soybean oil, lactate and surfactants) could release substrate to enhance the TCE dechlorination. In this study, a biobarrier comprising PS injection wells was installed. Injection wells were installed at 5-m intervals, and approximately 15 L of PS was injected into each well. Results show that TCE concentrations in the injection wells dropped from an average of 87 μg/L to below 1 μg/L after 35 days of PS injection. The total organic carbon concentrations in the injection wells increased from an average of 2.1-543 mg/L after 30 days of PS injection. The dissolved oxygen (DO) concentrations and oxidation-reduction potential (ORP) values dropped from an average of 1.6 mg/L to below 0.1 mg/L and from 124 mv to -14 mv after 20 days of injection, respectively. The DO and ORP remained in anaerobic conditions during the remaining 100 days of the operational period. TCE degradation by-products were observed in groundwater samples during the operational period. This reveals that the addition of PS could effectively enhance the reductive dechlorinating of TCE. PMID:24845323

  15. Modulation of trichloroethylene in vitro metabolism by different drugs in human.

    PubMed

    Cheikh Rouhou, Mouna; Haddad, Sami

    2014-08-01

    Toxicological interactions with drugs have the potential to modulate the toxicity of trichloroethylene (TCE). Our objective is to identify metabolic interactions between TCE and 14 widely used drugs in human suspended hepatocytes and characterize the strongest using microsomal assays. Changes in concentrations of TCE and its metabolites were measured by headspace GC-MS. Results with hepatocytes show that amoxicillin, cimetidine, ibuprofen, mefenamic acid and ranitidine caused no significant interactions. Naproxen and salicylic acid showed to increase both TCE metabolites levels, whereas acetaminophen, carbamazepine and erythromycin rather decreased them. Finally, diclofenac, gliclazide, sulphasalazine and valproic acid had an impact on the levels of only one metabolite. Among the 14 tested drugs, 5 presented the most potent interactions and were selected for confirmation with microsomes, namely naproxen, salicylic acid, acetaminophen, carbamazepine and valproic acid. Characterization in human microsomes confirmed interaction with naproxen by competitively inhibiting trichloroethanol (TCOH) glucuronidation (Ki=2.329 mM). Inhibition of TCOH formation was also confirmed for carbamazepine (partial non-competitive with Ki=70 μM). Interactions with human microsomes were not observed with salicylic acid and acetaminophen, similar to prior results in rat material. For valproic acid, interactions with microsomes were observed in rat but not in human. Inhibition patterns were shown to be similar in human and rat hepatocytes, but some differences in mechanisms were noted in microsomal material between species. Next research efforts will focus on determining the adequacy between in vitro observations and the in vivo situation. PMID:24632077

  16. Immunological techniques as tools to characterize the subsurface microbial community at a trichloroethylene contaminated site

    SciTech Connect

    Fliermans, C.B.; Dougherty, J.M.; Franck, M.M.; McKinzey, P.C.; Hazen, T.C.

    1992-12-31

    Effective in situ bioremediation strategies require an understanding of the effects pollutants and remediation techniques have on subsurface microbial communities. Therefore, detailed characterization of a site`s microbial communities is important. Subsurface sediment borings and water samples were collected from a trichloroethylene (TCE) contaminated site, before and after horizontal well in situ air stripping and bioventing, as well as during methane injection for stimulation of methane-utilizing microorganisms. Subsamples were processed for heterotrophic plate counts, acridine orange direct counts (AODC), community diversity, direct fluorescent antibodies (DFA) enumeration for several nitrogen-transforming bacteria, and Biolog {reg_sign} evaluation of enzyme activity in collected water samples. Plate counts were higher in near-surface depths than in the vadose zone sediment samples. During the in situ air stripping and bioventing, counts increased at or near the saturated zone, remained elevated throughout the aquifer, but did not change significantly after the air stripping. Sporadic increases in plate counts at different depths as well as increased diversity appeared to be linked to differing lithologies. AODCs were orders of magnitude higher than plate counts and remained relatively constant with depth except for slight increases near the surface depths and the capillary fringe. Nitrogen-transforming bacteria, as measured by serospecific DFA, were greatly affected both by the in situ air stripping and the methane injection. Biolog{reg_sign} activity appeared to increase with subsurface stimulation both by air and methane. The complexity of subsurface systems makes the use of selective monitoring tools imperative.

  17. Immunological techniques as tools to characterize the subsurface microbial community at a trichloroethylene contaminated site

    SciTech Connect

    Fliermans, C.B.; Dougherty, J.M.; Franck, M.M.; McKinzey, P.C.; Hazen, T.C.

    1992-01-01

    Effective in situ bioremediation strategies require an understanding of the effects pollutants and remediation techniques have on subsurface microbial communities. Therefore, detailed characterization of a site's microbial communities is important. Subsurface sediment borings and water samples were collected from a trichloroethylene (TCE) contaminated site, before and after horizontal well in situ air stripping and bioventing, as well as during methane injection for stimulation of methane-utilizing microorganisms. Subsamples were processed for heterotrophic plate counts, acridine orange direct counts (AODC), community diversity, direct fluorescent antibodies (DFA) enumeration for several nitrogen-transforming bacteria, and Biolog [reg sign] evaluation of enzyme activity in collected water samples. Plate counts were higher in near-surface depths than in the vadose zone sediment samples. During the in situ air stripping and bioventing, counts increased at or near the saturated zone, remained elevated throughout the aquifer, but did not change significantly after the air stripping. Sporadic increases in plate counts at different depths as well as increased diversity appeared to be linked to differing lithologies. AODCs were orders of magnitude higher than plate counts and remained relatively constant with depth except for slight increases near the surface depths and the capillary fringe. Nitrogen-transforming bacteria, as measured by serospecific DFA, were greatly affected both by the in situ air stripping and the methane injection. Biolog[reg sign] activity appeared to increase with subsurface stimulation both by air and methane. The complexity of subsurface systems makes the use of selective monitoring tools imperative.

  18. Effects of toxicity, aeration, and reductant supply on trichloroethylene transformation by a mixed methanotrophic culture.

    PubMed Central

    Alvarez-Cohen, L; McCarty, P L

    1991-01-01

    The trichloroethylene (TCE) transformation rate and capacity of a mixed methanotrophic culture at room temperature were measured to determine the effects of time without methane (resting), use of an alternative energy source (formate), aeration, and toxicity of TCE and its transformation products. The initial specific TCE transformation rate of resting cells was 0.6 mg of TCE per mg of cells per day, and they had a finite TCE transformation capacity of 0.036 mg of TCE per mg of cells. Formate addition resulted in increased initial specific TCE transformation rates (2.1 mg/mg of cells per day) and elevated transformation capacity (0.073 mg of TCE per mg of cells). Significant declines in methane conversion rates following exposure to TCE were observed for both resting and formate-fed cells, suggesting toxic effects caused by TCE or its transformation products. TCE transformation and methane consumption rates of resting cells decreased with time much more rapidly when cells were shaken and aerated than when they remained dormant, suggesting that the transformation ability of methanotrophs is best preserved by storage under anoxic conditions. PMID:2036009

  19. Long-term effects of dissolved carbonate species on the degradation of trichloroethylene by zerovalent iron.

    PubMed

    Parbs, Anika; Ebert, Markus; Dahmke, Andreas

    2007-01-01

    The effect of different concentrations of total inorganic carbon (TIC) and flow rates on the reactivity of iron metal with trichloroethylene (TCE) was studied in column experiments to verify whether concentration or mass flux of TIC is the major key parameter for barrier performance. First-order rate coefficients (kobs) for TCE degradation vary initially between 0.15 and 0.32 h-' and are positively related to TIC influent concentration. Maximal kobs were reached after 164 and 591 PV, varied between 0.55 and 1.1 h(-1), and were positively correlated to the TIC mass flux, followed by a decrease resulting in values similar to the reference system at the end of the experiments. Enhancement of iron corrosion (0.7 to 3.5 mmol kgFe(-1) d(-1) and formation of gas bubbles during the initial experimental phase were observed and were also positively correlated to TIC mass flux. The higher gas bubble formation probably has a more significant effect on porosity than mineral precipitations in Fe0-systems. The results suggest that higher TIC mass fluxes cause a more pronounced acceleration in CHC degradation, but also a faster inhibition in the longer-term. This faster inhibition has serious implication for the design of funnel and gate systems. PMID:17265961

  20. VHL mutations in renal cell cancer: does occupational exposure to trichloroethylene make a difference?

    PubMed

    Brauch, Hiltrud; Weirich, Gregor; Klein, Bettina; Rabstein, Sylvia; Bolt, Hermann M; Brüning, Thomas

    2004-06-15

    Occupational exposures have long been suspected to play a role in the incidence of renal cell carcinoma (RCC). Especially, the carcinogenicity of the industrial solvent trichloroethylene (TCE) has been controversially debated, both with respect to the epidemiological and the molecular studies. In order to further elucidate this issue, it appeared important to compare suitable RCC patient groups, i.e., TCE-exposed versus non-TCE-exposed patients. We evaluated RCC from a previous German study that had described differences in RCC risks between TCE-exposed (n=17) and non-exposed patients (n=21). We compared age at diagnosis and histopathologic parameters of tumors as well as somatic mutation characteristics in the kidney cancer causing VHL tumor suppressor gene. RCC did not differ with respect to histopathological characteristics in both patient groups. We noticed a younger age at diagnosis in TCE-exposed patients compared to non-exposed patients (P=0.01). Moreover, the non-TCE-exposed patients did not share the somatic VHL mutation characteristics of TCE-exposed patients such as the previously identified hot spot mutation 454 C > T P81S or multiple mutations. These data support the notion of a putative genotoxic effect of TCE leading to VHL gene damage and subsequent occurrence of RCC in highly exposed subjects. PMID:15177666

  1. Differential Immunotoxicity Induced by Two Different Windows of Developmental Trichloroethylene Exposure

    PubMed Central

    Gilbert, Kathleen M.; Woodruff, William; Blossom, Sarah J.

    2014-01-01

    Developmental exposure to environmental toxicants may induce immune system alterations that contribute to adult stage autoimmune disease. We have shown that continuous exposure of MRL+/+ mice to trichloroethylene (TCE) from gestational day (GD) 0 to postnatal day (PND) 49 alters several aspects of CD4+ T cell function. This window of exposure corresponds to conception-adolescence/young adulthood in humans. More narrowly defining the window of TCE developmental exposure causes immunotoxicity that would establish the stage at which avoidance and/or intervention would be most effective. The current study divided continuous TCE exposure into two separate windows, namely, gestation only (GD0 to birth (PND0)) and early-life only (PND0-PND49). The mice were examined for specific alterations in CD4+ T cell function at PND49. One potentially long-lasting effect of developmental exposure, alterations in retrotransposon expression indicative of epigenetic alterations, was found in peripheral CD4+ T cells from both sets of developmentally exposed mice. Interestingly, certain other effects, such as alterations in thymus cellularity, were only found in mice exposed to TCE during gestation. In contrast, expansion of memory/activation cell subset of peripheral CD4+ T cells were only found in mice exposed to TCE during early life. Different windows of developmental TCE exposure can have different functional consequences. PMID:24696780

  2. Gene expression profiling in the fetal cardiac tissue after folate and low dose trichloroethylene exposure

    PubMed Central

    Caldwell, Patricia T.; Manziello, Ann; Howard, Jamie; Palbykin, Brittany; Runyan, Raymond B.; Selmin, Ornella

    2014-01-01

    Background Previous studies show gene expression alterations in rat embryo hearts and cell lines that correspond to the cardio-teratogenic effects of trichloroethylene (TCE) in animal models. One potential mechanism of TCE teratogenicity may be through altered regulation of calcium homeostatic genes with a corresponding inhibition of cardiac function. It has been suggested that TCE may interfere with the folic acid/methylation pathway in liver and kidney and alter gene regulation by epigenetic mechanisms. According to this hypothesis, folate supplementation in the maternal diet should counteract TCE effects on gene expression in the embryonic heart. Approach To identify transcriptional targets altered in the embryonic heart after exposure to TCE, and possible protective effects of folate, we used DNA microarray technology to profile gene expression in embryonic mouse hearts with maternal TCE exposure and dietary changes in maternal folate. Results Exposure to low doses of TCE (10ppb) caused extensive alterations in transcripts encoding proteins involved in transport, ion channel, transcription, differentiation, cytoskeleton, cell cycle and apoptosis. Exogenous folate did not offset the effects of TCE exposure on normal gene expression and both high and low levels of folate produced additional significant changes in gene expression. Conclusions A mechanism where TCE induces a folate deficiency does not explain altered gene expression patterns in the embryonic mouse heart. The data further suggest that use of folate supplementation, in the presence of this toxin, may be detrimental and non-protective of the developing embryo. PMID:19813261

  3. Photocatalytic degradation of trichloroethylene in aqueous phase using nano-ZNO/Laponite composites.

    PubMed

    Joo, Jin Chul; Ahn, Chang Hyuk; Jang, Dae Gyu; Yoon, Young Han; Kim, Jong Kyu; Campos, Luiza; Ahn, Hosang

    2013-12-15

    The feasibility of nano-ZnO/Laponite composites (NZLc) as a valid alternative to TiO2 to mineralize trichloroethylene (TCE) without difficulties for recovery of photocatalysts was evaluated. Based on the experimental observations, the removal of TCE using NZLc under UV irradiation was multiple reaction processes (i.e., sorption, photolysis, and photocatalysis). Sorption of TCE was thermodynamically favorable due to the hydrophobic partitioning into crosslinked poly vinyl alcohol, and the adsorption onto high-surface-area mineral surfaces of both ZnO and Laponite. The degradation efficiency of TCE can be significantly improved using NZLc under UV irradiation, indicating that ZnO-mediated heterogeneous photocatalytic degradation occurred. However, the degradation efficiency was found to vary with experimental conditions (e.g., initial concentration of TCE, loading amount of NZLc, the intensity of light and initial solution pH). Although the removal of TCE by NZLc was found to be a complex function of sorption, photolysis, and photocatalysis, the photocatalytic degradation of TCE on the surface of ZnO was critical. Consequently, developed NZLc can be applied as a valid alternative to suspended TiO2 powder, and overcome drawbacks (e.g., filtration and recovery of photocatalysts) in degradation of TCE for various water resources. PMID:24239256

  4. Biodegradation of 1,4-dioxane: effects of enzyme inducers and trichloroethylene.

    PubMed

    Hand, Steven; Wang, Baixin; Chu, Kung-Hui

    2015-07-01

    1,4-Dioxane is a groundwater contaminant and probable human carcinogen. In this study, two well-studied degradative bacteria Mycobacterium vaccae JOB5 and Rhodococcus jostii RHA1 were examined for their 1,4-dioxane degradation ability in the presence and absence of its co-contaminant, trichloroethylene (TCE), under different oxygenase-expression conditions. These two strains were precultured with R2A broth (complex nutrient medium) before supplementation with propane or 1-butanol to induce the expression of different oxygenases. Both propane- and 1-butanol-induced JOB5 and RHA1 were able to degrade 1,4-dioxane, TCE, and mixtures of 1,4-dioxane/TCE. Complete degradation of 1,4-dioxane/TCE mixture was observed only in propane-induced strain JOB5. Inhibition was observed between 1,4-dioxane and TCE for all cells. Furthermore, product toxicity caused incomplete degradation of 1,4-dioxane by 1-butanol-induced JOB5. In general, the more TCE degraded, the greater extent of product toxicity cells experienced; however, susceptibility to product toxicity was found to be both strain- and inducer-dependent. The findings of this study provide fundamental basis for developing an effective in-situ remediation method for 1,4-dioxane-contaminated ground water and the first known study of 1,4-dioxane degradation by wild-type strain RHA1. PMID:25813968

  5. The kinetics of the combustion of trichloroethylene for low Cl/H ratios

    SciTech Connect

    Werner, J.H.; Cool, T.A.

    2000-01-01

    A kinetic model has been developed for the combustion of trichloroethylene (TCE) under low Cl/H ratio conditions. Flame species concentration profiles, measured for CH{sub 4}/O{sub 2}/Ar flames, reveal that the most important reaction channels in the decomposition of TCE in the CH{sub 4}/TCE/O{sub 2}/Ar flame are the displacement by H atoms of Cl atoms from TCE,1,1-dichloroethylene (DCE), and vinyl chloride. The displacement of Cl atoms from TCE by OH also contributes to the decomposition of TCE, and leads to the production of 2,2-dichloroethanol, a species unobserved in previous flame studies. Other species found in large concentrations in the present CH{sub 4}/TCE/O{sub 2}/Ar flames, but not observed in previous TCE/O{sub 2}/Ar flame studies at higher chlorine-too-hydrogen ratios, are ketene, chloroketene, and dichloroketene. Finally, the presence of TCE catalyzes the formation of C{sub 3}-C{sub 6} hydrocarbons. The presence of significant concentrations of C{sub 3}H{sub 3}, C{sub 3}H{sub 4}, and C{sub 6}H{sub 6} is consistent with odd carbon species mechanisms previously suggested for benzene formation in hydrocarbon flames.

  6. Continuous degradation of trichloroethylene by Xanthobacter sp. strain Py2 during growth on propene

    SciTech Connect

    Reij, M.W.; Kieboom, J.; De Bont, J.A.M.; Hartmans, S.

    1995-08-01

    Propene-grown Xanthobacter sp. strain Py2 cells can degrade trichloroethylene (TCE), but the transformation capacity of such cells was limited and depended on both the TCE concentration and the biomass concentration. Toxic metabolites presumably accumulated extracellularly, because the fermentation of glucose by yeast cells was inhibited by TCE degradation products formed by strain Py2. The affinity of the propene monooxygenase for TCE was low, and this allowed strain Py2 to grow on propene in the presence of TCE. During batch growth with propene and TCE, the TCE was not degraded before most of the propene had been consumed. Continuous degradation of TCE in a chemostat culture of strain Py2 growing with propene was observed with TCE concentrations up to 206 {mu}M in the growth medium without washout of the fermentor occurring. At this TCE concentration the specific degradation rate was 1.5 nmol/min/mg of biomass. The total amount of TCE that could be degraded during simultaneous growth on propene depended on the TCE concentration and ranged from 0.03 to 0.34 g of TCE per g of biomass. The biomass yield on propene was not affected by the cometabolic degradation of TCE. 23 refs., 5 figs., 2 tabs.

  7. Deactivation model for the adsorption of trichloroethylene vapor on an activated carbon bed

    SciTech Connect

    Suyadal, Y.; Erol, M.; Oguz, H.

    2000-03-01

    In this work, the adsorption of trichloroethylene (TCE) vapor was investigated in a laboratory-scale packed-bed adsorber by using granular activated carbon (GAC) at constant pressure (101.3 kPa). The packed-bed adsorber (PBA) was operated batchwise with the charges of GAC particles in the ranges of 2.5--10.0 g for obtaining TCE breakthrough curves. Experiments were carried out at different temperatures (25.6 {le} T({degree}C) {le} 35.8) and TCE feedstock concentrations (6,350 {le} C (ppm TCE) {le} 7,950) within the range of space velocity (5,000 {le} {var_theta} (h{sup {minus}1}) {le} 17,000). The effects of TCE inlet concentration, operating temperature, and mass of adsorbent (m{sub Ads}) on the TCE breakthrough curves were investigated, respectively. The deactivation model (DM) was tested for these curves by using the analogy between the adsorption of TCE and the deactivation of catalyst particles. Observed adsorption rate constants (k{sub S}) and first-order deactivation rate constants (k{sub d}) were obtained from the model. It was found that the deactivation model describes the experimental breakthrough curves more accurately compared to the adsorption isotherms given in the literature.

  8. Concentration of Trichloroethylene in Breast Milk and Household Water from Nogales, Arizona

    PubMed Central

    Beamer, Paloma I.; Luik, Catherine E.; Abrell, Leif; Campos, Swilma; Martínez, María Elena; Sáez, A. Eduardo

    2013-01-01

    The United States Environmental Protection Agency has identified quantification of trichloroethylene (TCE), an industrial solvent, in breast milk as a high priority need for risk assessment. Water and milk samples were collected from 20 households by a lactation consultant in Nogales, Arizona. Separate water samples (including tap, bottled and vending machine) were collected for all household uses: drinking, bathing, cooking, and laundry. A risk factor questionnaire was administered. Liquid-liquid extraction with diethyl ether was followed by GC-MS for TCE quantification in water. Breast milk underwent homogenization, lipid hydrolysis and centrifugation prior to extraction. The limit of detection was 1.5 ng/mL. TCE was detected in 7 of 20 mothers’ breast milk samples. The maximum concentration was 6 ng/mL. TCE concentration in breast milk was significantly correlated with the concentration in water used for bathing (ρ=0.59, p=0.008). Detection of TCE in breast milk was more likely if the infant had a body mass index <14 (RR=5.2, p=0.02). Based on average breast milk consumption, TCE intake for 5% of the infants may exceed the proposed US EPA Reference Dose. Results of this exploratory study warrant more in depth studies to understand risk of TCE exposures from breast milk intake. PMID:22827160

  9. Phase-transfer catalysis applied to the oxidation of nonaqueous phase trichloroethylene by potassium permanganate

    SciTech Connect

    Seol, Yongkoo; Schwartz, Franklin W.

    1999-01-02

    The use of potassium permanganate to oxidize chlorinated solvents has been demonstrated as an effective process for treating nonaqueous phase liquids in ground-water systems. This study evaluates the effectiveness of phase-transfer catalysts (PTCs) in enhancing the degradation rate. PTCs work by transferring permanganate ion into the nonaqueous phase where it initiates oxidative decomposition. We studied the oxidation of trichloroethylene (TCE) by potassium permanganate, conducting kinetic batch experiments in conjunction with three PTCs that varied in terms of their extraction constants and molecular structures. Using the same batch technique, we examined whether PTCs could enhance the aqueous solubility of TCE. Solubilization could also increase oxidation rates in the aqueous phase. Rates of TCE oxidation in solutions containing the PTCs and a blank were estimated separately by measuring chloride concentration and UV-Vis absorbance in the aqueous phase. The enhanced rate of TCE destruction by the PTCs was reflected by an increase in the rate of consumption of permanganate ion and production of chloride ion. There was no tendency for the PTCs, however, to solubilize TCE in the aqueous phase. Therefore, the PTCs increased the rate of TCE decomposition by catalyzing permanganate oxidation in the organic phase. This study suggests that there is significant potential for testing this scheme under field conditions.

  10. Electrochemical transformation of trichloroethylene in aqueous solution by electrode polarity reversal

    PubMed Central

    Rajic, Ljiljana; Fallahpour, Noushin; Yuan, Songhu; Alshawabkeh, Akram N.

    2014-01-01

    Electrode polarity reversal is evaluated for electrochemical transformation of trichloroethylene (TCE) in aqueous solution using flow-through reactors with mixed metal oxide electrodes and Pd catalyst. The study tests the hypothesis that optimizing electrode polarity reversal will generate H2O2 in Pd presence in the system. The effect of polarity reversal frequency, duration of the polarity reversal intervals, current intensity and TCE concentration on TCE removal rate and removal mechanism were evaluated. TCE removal efficiencies under 6 cycles h−1 were similar in the presence of Pd catalyst (50.3%) and without Pd catalyst (49.8%), indicating that Pd has limited impact on TCE degradation under these conditions. The overall removal efficacies after 60 min treatment under polarity reversal frequencies of 6, 10, 15, 30 and 90 cycles h−1 were 50.3%, 56.3%, 69.3%, 34.7% and 23.4%, respectively. Increasing the frequency of polarity reversal increases TCE removal as long as sufficient charge is produced during each cycle for the reaction at the electrode. Electrode polarity reversal shifts oxidation/reduction and reduction/oxidation sequences in the system. The optimized polarity reversal frequency (15 cycles h−1 at 60 mA) enables two reaction zones formation where reduction/oxidation occurs at each electrode surface. PMID:25282093

  11. Effects of diverse organic contaminants on trichloroethylene degradation by methanotrophic bacteria and methane-utilizing consortia

    SciTech Connect

    Palumbo, A.V.; Boerman, P.A.; Herbes, S.E. . Environmental Sciences Div.); Eng, W. . Center for Health Sciences); Strandberg, G.W.; Donaldson, T.L. . Chemical Technology Div.)

    1991-01-01

    Groundwater contaminated with organic compounds, especially solvents such as benzene, trichloroethylene (TCE), perchloroethene (PCE), carbon tetrachloride, and chlorinated ethanes, is a problem at many US Department of Energy facilities including the Oak Ridge National Laboratory (ORNL). Regulations require consideration of alternatives for remediation of these sites. A demonstration project was initiated in the spring of 1990 that will permit evaluation of two cometabolic approaches to remediation of groundwater and may lead to remediation alternatives that prove both more effective and less costly than traditional methods. More generally, the demonstration will provide valuable information on the applicability of bioremediation to a groundwater contamination problem at numerous DOE sites. The purpose of this research is to examine the effects of contaminants commonly found in association with TCE at DOE sites and to determine the conditions required for maximizing TCE degradation rates. This study focuses on compounds found in a seep at the ORNL K-25 site. The research presented here details initial experiments on TCE degradation by methanotrophs conducted in the presence of a synthetic medium, TCE, and one or more contaminants found at the K-25 site. Formate has been reported to increase the rate of TCE degradation by pure cultures but had not been tested with mixed cultures. As part of the effort to maximize TCE degradation rates, we examined the effect of formate on degradation by a mixed culture. 5 figs., 1 tab.

  12. Catalytic hydrodechlorination of trichloroethylene in water with supported CMC-stabilized palladium nanoparticles.

    PubMed

    Zhang, Man; Bacik, Deborah B; Roberts, Christopher B; Zhao, Dongye

    2013-07-01

    In this work, we developed and tested a new class of supported Pd catalysts by immobilizing CMC (carboxymethyl cellulose) stabilized Pd nanoparticles onto alumina support. The alumina supported Pd nanoparticles were able to facilitate rapid and complete hydrodechlorination of TCE (trichloroethylene) without intermediate by-products detected. With a Pd mass loading of 0.33 wt% of the alumina mass, the observed pseudo first order reaction rate constant, k(obs), for the catalyst was increased from 28 to 109 L/min/g when CMC concentration was raised from 0.005 to 0.15 wt%. The activity increase was in accord with an increase of the Pd dispersion (measured via CO chemisorption) from 30.4% to 45.1%. Compared to the commercial alumina supported Pd, which has a lower Pd dispersion of 21%, our CMC-stabilized Pd nanoparticles offered more than 7 times greater activity. Pre-calcination treatment of the supported catalyst resulted in minor drop in activity, yet greatly reduced bleeding (<6%) of the Pd nanoparticles from the support during multiple cycles of applications. The presence of DOM (dissolved organic matter) at up to 10 mg/L as TOC had negligible effect on the catalytic activity. The alumina supported CMC-stabilized Pd nanoparticles may serve as a class of more effective catalysts for water treatment uses. PMID:23726707

  13. A Study of Groundwater Matrix Effects for the Destruction of Trichloroethylene Using Fe/Pd Nanoaggregates.

    PubMed

    Meyer, D E; Hampson, S; Ormsbee, L; Bhattacharyya, D

    2009-01-30

    Iron nanoaggregates have been prepared using the sodium borohydride reduction method and post-coated with Pd using aqueous phase electro-deposition. The Fe/Pd nanoaggregates were used to examine dechlorination of trichloroethylene (TCE) with regard to matrix effects using materials representative of a potential zero-valent metal remediation site surrounding the Paducah gaseous diffusion plant in Paducah, KY. A surface-area-normalized first-order rate constant of 1.4 x 10(-1) L m(-2) h(-1) was obtained for the case of ideal dechlorination of 19.6 mg L(-1) TCE at room temperature and pH 6.2 using 0.5 g L(-1) Fe/Pd (0.42 wt % Pd) loading. This value decreases by an order of magnitude to 1.9 x 10(-2) L m(-2) h(-1) when the reaction is carried out in a realistic background matrix when the pH is high (8.8). For all variables tested, Pd content has the most impact on reaction rates. Circulating batch-column experiments are used to study dechlorination under flow conditions and demonstrate the ability of nonstabilized Fe/Pd nanoaggregates to remove significant amounts of TCE (80-90%) over a broad range of groundwater velocities (12.9-83 ft per day) using moderate metal loadings (0.23-0.5 g L(-1)). PMID:20526423

  14. An analysis of trichloroethylene movement in groundwater at castle Air Force Base, California

    USGS Publications Warehouse

    Avon, L.; Bredehoeft, J.D.

    1989-01-01

    A trichloroethylene (TCE) plume has been identified in the groundwater under a U.S. Air Force Base in the Central Valley of California. An areal, two-dimensional numerical solute transport model indicates that the movement of TCE due to advection, dispersion, and linear sorption is simulated over a 25-year historic period. The model is used in several ways: (1) to estimate the extent of the plume; (2) to confirm the likely sources of contamination as suggested by a soil organic vapor survey of the site; and (3) to make predictions about future movement of the plume. Despite the noisy and incomplete data set, the model reproduces the general trends in contamination at a number of observation wells. The analysis indicates that soil organic vapor monitoring is an effective tool for identifying contaminant source locations. Leaky sewer pipes and underground tanks are the indicated pathways for TCE to have entered the groundwater system. The chemical mass balance indicates that a total of about 100 gallons of TCE - a relatively small amount of organic solvent - has created the observed groundwater plume. ?? 1989.

  15. In situ detection of organic molecules: Optrodes for TCE (trichloroethylene) and CHCl sub 3

    SciTech Connect

    Angel, S. M.; Langry, K. C.; Ridley, M. N.

    1990-05-01

    We have developed new absorption-based chemical indicators for detecting chloroform (CHCl{sub 3}) and trichloroethylene (TCE). These indicators were used to make very sensitive optical chemical sensors (optrodes) for each of these two contaminants. Concentrations below 10 ppb can be accurately measured using these sensors. Furthermore, they are selective and do not response to similar contaminants commonly found with TCE and CHCl{sub 3} in contaminated groundwater. In addition, the sensor response is linearly proportional to the chemical concentration. In this report, we describe the details of this optrode and the putative reaction sequences of the indicator chemistries with CHCl{sub 3} and TCE and present an analysis of the spectral data obtained from the reaction products. A key part of the development of this optrode was designing a simple readout device. The readout is a dual-channel fiber-optic fluorimeter modified to measure transmission or absorption of light. The system is controlled by a lap-top microcomputer and is fully field portable. In addition to describing the final absorption optrode, details of the chemical indicator reactions are presented for both absorption- (colorimetric) and fluorescence-based optrodes. Finally, we report on the syntheses of several compounds used to evaluate the indicator chemical reactions that led to the development of the absorption optrode. 23 refs., 26 figs., 1 tab.

  16. Soluble methane monooxygenase component B gene probe for identification of methanotrophs that rapidly degrade trichloroethylene

    SciTech Connect

    Hsienchyang Tsien; Hanson, R.S. )

    1992-03-01

    Restriction fragment length polymorphisms, Western blot (immunoblot) analysis, and fluorescence-labelled signature probes were used for the characterization of methanotrophic bacteria as well as for the identification of methanotrophs which contained the soluble methane monooxygenase (MMO) gene and were able to degrade trichloroethylene (TCE). The gene encoding a soluble MMO component B protein from Methylosinus trichosporium OB3b was cloned. It contained a 2.2-kb EcoRI fragment. With this cloned component B gene as probe, methanotroph types I, II, and X and environmental and bioreactor samples were screened for the presence of the gene encoding soluble MMO. Among twelve pure or mixed cultures, DNA fragments of seven methanotrophs hybridized with the soluble MMO B gene probe. When grown in media with limited copper, all of these bacteria degraded TCE. All of them are type II methanotrophs. The soluble MMO component B gene of the type X methanotroph, Methylococcus capsulatus Bath, did not hybridize to the M. trichosporium OB3b soluble MMO component B gene probe, although M. capsulatus Baath also produces a soluble MMO.

  17. The Relationship between the Occupational Exposure of Trichloroethylene and Kidney Cancer

    PubMed Central

    2014-01-01

    Trichloroethylene (TCE) has been widely used as a degreasing agent in many manufacturing industries. Recently, the International Agency for Research on Cancer presented “sufficient evidence” for the causal relationship between TCE and kidney cancer. The aim of this study was to review the epidemiologic evidences regarding the relationship between TCE exposure and kidney cancer in Korean work environments. The results from the cohort studies were inconsistent, but according to the meta-analysis and case–control studies, an increased risk for kidney cancer was present in the exposure group and the dose–response relationship could be identified using various measures of exposure. In Korea, TCE is a commonly used chemical for cleaning or degreasing processes by various manufacturers; average exposure levels of TCE vary widely. When occupational physicians evaluate work-relatedness kidney cancers, they must consider past exposure levels, which could be very high (>100 ppm in some cases) and associated with jobs, such as plating, cleaning, or degreasing. The exposure levels at a manual job could be higher than an automated job. The peak level of TCE could also be considered an important exposure-related variable due to the possibility of carcinogenesis associated with high TCE doses. This review could be a comprehensive reference for assessing work-related TCE exposure and kidney cancer in Korea. PMID:24955246

  18. A Study of Groundwater Matrix Effects for the Destruction of Trichloroethylene Using Fe/Pd Nanoaggregates

    PubMed Central

    Meyer, D.E.; Hampson, S.; Ormsbee, L.; Bhattacharyya, D.

    2010-01-01

    Iron nanoaggregates have been prepared using the sodium borohydride reduction method and post-coated with Pd using aqueous phase electro-deposition. The Fe/Pd nanoaggregates were used to examine dechlorination of trichloroethylene (TCE) with regard to matrix effects using materials representative of a potential zero-valent metal remediation site surrounding the Paducah gaseous diffusion plant in Paducah, KY. A surface-area-normalized first-order rate constant of 1.4 × 10–1 L m–2 h–1 was obtained for the case of ideal dechlorination of 19.6 mg L–1 TCE at room temperature and pH 6.2 using 0.5 g L–1 Fe/Pd (0.42 wt % Pd) loading. This value decreases by an order of magnitude to 1.9 × 10–2 L m–2 h–1 when the reaction is carried out in a realistic background matrix when the pH is high (8.8). For all variables tested, Pd content has the most impact on reaction rates. Circulating batch-column experiments are used to study dechlorination under flow conditions and demonstrate the ability of nonstabilized Fe/Pd nanoaggregates to remove significant amounts of TCE (80–90%) over a broad range of groundwater velocities (12.9–83 ft per day) using moderate metal loadings (0.23–0.5 g L–1). PMID:20526423

  19. Phase-transfer catalysis applied to the oxidation of nonaqueous phase trichloroethylene by potassium permanganate

    NASA Astrophysics Data System (ADS)

    Seol, Yongkoo; Schwartz, Franklin W.

    2000-07-01

    The use of potassium permanganate to oxidize chlorinated solvents has been demonstrated as an effective process for treating nonaqueous phase liquids in ground-water systems. This study evaluates the effectiveness of phase-transfer catalysts (PTCs) in enhancing the degradation rate. PTCs work by transferring permanganate ion into the nonaqueous phase where it initiates oxidative decomposition. We studied the oxidation of trichloroethylene (TCE) by potassium permanganate, conducting kinetic batch experiments in conjunction with three PTCs that varied in terms of their extraction constants and molecular structures. Using the same batch technique, we examined whether PTCs could enhance the aqueous solubility of TCE. Solubilization could also increase oxidation rates in the aqueous phase. Rates of TCE oxidation in solutions containing the PTCs and a blank were estimated separately by measuring chloride concentration and UV-Vis absorbance in the aqueous phase. The enhanced rate of TCE destruction by the PTCs was reflected by an increase in the rate of consumption of permanganate ion and production of chloride ion. There was no tendency for the PTCs, however, to solubilize TCE in the aqueous phase. Therefore, the PTCs increased the rate of TCE decomposition by catalyzing permanganate oxidation in the organic phase. This study suggests that there is significant potential for testing this scheme under field conditions.

  20. Kinetics of chlorinated hydrocarbon degradation by Methylosinus trichosporium OB3b and toxicity of trichloroethylene.

    PubMed Central

    Oldenhuis, R; Oedzes, J Y; van der Waarde, J J; Janssen, D B

    1991-01-01

    The kinetics of the degradation of trichloroethylene (TCE) and seven other chlorinated aliphatic hydrocarbons by Methylosinus trichosporium OB3b were studied. All experiments were performed with cells grown under copper stress and thus expressing soluble methane monooxygenase. Compounds that were readily degraded included chloroform, trans-1,2-dichloroethylene, and TCE, with Vmax values of 550, 330, and 290 nmol min-1 mg of cells-1, respectively. 1,1-Dichloroethylene was a very poor substrate. TCE was found to be toxic for the cells, and this phenomenon was studied in detail. Addition of activated carbon decreased the acute toxicity of high levels of TCE by adsorption, and slow desorption enabled the cells to partially degrade TCE. TCE was also toxic by inactivating the cells during its conversion. The degree of inactivation was proportional to the amount of TCE degraded; maximum degradation occurred at a concentration of 2 mumol of TCE mg of cells-1. During conversion of [14C]TCE, various proteins became radiolabeled, including the alpha-subunit of the hydroxylase component of soluble methane monooxygenase. This indicated that TCE-mediated inactivation of cells was caused by nonspecific covalent binding of degradation products to cellular proteins. Images PMID:2036023