Dissertations / Theses on the topic 'Trichloroethylene'
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1
Yaqoob, Noreen. "Studies on trichloroethylene-induced formic aciduria." Thesis, Liverpool John Moores University, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.526913.
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Randall, Debra Jean 1955. "TUMOR-PROMOTING EFFECTS OF TRICHLOROETHYLENE (NEONATAL, MOUSE)." Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/291251.
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Wei, Zongsu. "Trichloroethylene (TCE) Adsorption Using Sustainable Organic Mulch." University of Toledo / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1279301053.
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Mishra, Dhananjay. "Electrochemical Deactivation of Nitrate, Arsenate, and Trichloroethylene." Diss., The University of Arizona, 2006. http://hdl.handle.net/10150/194084.
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This research investigated the mechanism, kinetics and feasibility of nitrate, arsenate, and trichloroethylene inactivation on zerovalent iron (ZVI), mixed-valent iron oxides, and boron doped diamond film electrode surfaces, respectively. Nitrate ( ) is a common co-contaminant at sites remediated using permeable reactive barriers (PRBs). Therefore, understanding nitrate reactions with ZVI is important for understanding the performance of PRBs. This study investigated the reaction mechanisms of with ZVI under conditions relevant to groundwater treatment. Tafel analysis and electrochemical impedance spectroscopy were used to probe the surface reactions. Batch experiments were used to study the reaction rate of with freely corroding and cathodically protected iron wires. The removal kinetics for the air formed oxide (AFO) were 2.5 times slower than that of water formed oxide (WFO).This research also investigated the use of slowly corroding magnetite (Fe3O4) and wustite (FeO) as reactive adsorbent media for removing As(V) from potable water. Observed corrosion rates for mixed valent iron oxides were found to be 15 times slower than that of zerovalent iron under similar conditions. Electrochemical and batch and column experiments were performed to study the corrosion behavior and gain a deeper understanding on the effects of water chemistry and operating parameters, such as, empty bed contact times, influent arsenic concentrations, dissolved oxygen levels and solution pH values and other competing ions. Reaction products were analyzed by X-Ray diffraction and XPS to determine the fate of the arsenic.This research also investigated use of boron doped diamond film electrodes for reductive dechlorination of trichloroethylene (TCE). TCE reduction resulted in nearly stoichiometric production of acetate. Rates of TCE reduction were found to be independent of the electrode potential at potentials below -1 V with respect to the standard hydrogen electrode (SHE). However, at smaller overpotentials, rates of TCE reduction were dependent on the electrode potential. Short lived species analysis and density functional simulations indicate that TCE reduction may occur by formation of a surface complex between TCE and carbonyl groups present on the surface.
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Makwana, Om. "THE EFFECTS OF TRICHLOROETHYLENE ON HEART DEVELOPMENT." Diss., The University of Arizona, 2010. http://hdl.handle.net/10150/204310.
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Trichloroethylene (TCE; TRI; C2HCl3) is an organic solvent used as an industrial degreasing agent. Due to its widespread use and volatile nature, TCE is a common environmental contaminant. Trichloroethylene exposure has been implicated in the etiology of heart defects in human populations and animal models. Recent data suggest misregulation of Ca2+ homeostasis in a cardiomyocyte cell line after TCE exposure (Caldwell, Thorne et al. 2008). We hypothesized that misregulation of Ca2+ homeostasis alters myocyte function and leads to changes in embryonic blood flow. In turn, changes in cardiac flow are known to cause cardiac malformations. To investigate this hypothesis we dosed developing chick embryos in ovo with environmentally relevant doses of TCE (8 ppb and 800 ppb). We then isolated RNA from embryos at crucial time points in development for real-time PCR analysis of markers for altered blood flow. Based on this analysis, we observed effects on ET-1 (Endothelin-1), NOS-3 (Nitric Oxide Synthase-3) and Krüppel-Like Factor 2 (KLF2) expression relative to TCE exposure. Additionally, we assessed cardiomyocyte function by isolating chick E18 cardiomyocytes from embryos exposed to TCE in ovo. Cells were measured for rate of contraction after pulsing with extracellular Ca2+ and electrical stimulation at a frequency of 1.0 Hz. These functional data showed an effect on Ca2+ handling in cardiomyocytes exposed to TCE. To investigate an apparent non-monotypic effect in the heart where 8 ppb produced a stronger effect than 800 ppb, we isolated RNA from the developing heart and AV Canal to investigate the expression of several candidate Cytochrome P450s (CYPs) related to TCE metabolism. We observed a significant induction of multiple CYP2 family members in the developing heart after low dose TCE exposure. Together, these data suggest cardio-specificity of TCE as a teratogen and may reflect a requirement for normal calcium regulation of contractile function during organ development.
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Lee, Seung-Bong. "Biodegradation of chlorinated ethene by pseudonocardia chlorethenivorans SL-1 /." Thesis, Connect to this title online; UW restricted, 2002. http://hdl.handle.net/1773/10109.
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Shanbhogue, Sai Sharanya. "Alginate Encapsulated Nanoparticle-Microorganism System for Trichloroethylene Remediation." Thesis, North Dakota State University, 2012. https://hdl.handle.net/10365/26675.
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Nanoscale zero-valent iron (NZVI) particles were encapsulated in calcium alginate capsules for application in environmental remediation. TCE degradation rates for encapsulated and bare NZVI were similar indicating no adverse effects of encapsulation on degradation kinetics. Microorganisms were separately encapsulated and used along with encapsulated NZVI and co-encapsulated in calcium alginate capsules. Batch experiments were performed to test the efficacy of the combined iron-Pseudomonas sp. (PpF1) system. The combined system removed 100% TCE over the first three hours of the experiment followed by 70% TCE removal post TCE re-dosing. Complete reduction of TCE was achieved by NZVI between 0-3 h and the second phase of treatment (3-36 h) was mostly achieved by microorganisms. Experiments conducted with co-encapsulated NZVI-D.BAV1 achieved 100% TCE removal. During the first three hours of the experiment 100% TCE removal was achieved by NZVI, and 100% removal was achieved post re-dosing where D.BAV1 accomplished the treatment.Department of Civil Engineering, North Dakota State University
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Culpepper, Johnathan D. "Reduction of tetrachloroethylene and trichloroethylene by magnetite revisted." Thesis, University of Iowa, 2017. https://ir.uiowa.edu/etd/5741.
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For this study, we revisited whether the common iron Fe mineral, magnetite Fe3O4 (s), can reduce tetrachloroethylene (PCE) and trichloroethylene (TCE) as discrepancies exist in the literature regarding rates and extent of reduction. We measured PCE and TCE reduction in batch reactors as a function of magnetite stoichiometry (x = Fe2+/Fe3+ ratio), solids loading, pH, and Fe(II) concentration. Our results show that magnetite reacts only slowly with TCE (t1/2 = 7.6 years) and is not reactive with PCE over 150 days. The addition of aqueous Fe(II) to magnetite suspensions, however, results in slow, but measurable PCE and TCE reduction under some conditions. The solubility of ferrous hydroxide, Fe(OH)2(s), appears to play an important role in whether magnetite reduces PCE and TCE. In addition, we found that Fe(OH)2(s) reduces PCE and TCE at high Fe(II) concentrations as well. At certain conditions degradation of the PCE and TCE is enhanced by an unexplored synergistic response from magnetite and ferrous hydroxide iron phases. Our work suggests that measuring dissolved Fe(II) concentration and pH may be used as indicators to predict whether PCE and TCE will be abiotically degraded by groundwater aquifer solids containing magnetite.
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Wang, Lei. "Tetrachloroethene (PCE) and trichloroethene (TCE) biogradation with bioreactors /." free to MU campus, to others for purchase, 2001. http://wwwlib.umi.com/cr/mo/fullcit?p3036865.
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Costanza, Jed. "Degradation of tetrachloroethylene and trichloroethylene under thermal remediation conditions." Diss., Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-08262005-021152/.
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Thesis (Ph. D.)--Civil & Environmental Engineering, Georgia Institute of Technology, 2006.Pennell, Kurt, Committee Chair ; Lawrence Bottomley, Committee Member ; James Mulholland, Committee Member ; Carolyn Ruppel, Committee Member ; D. Webster, Committee Member. Includes bibliographical references.
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Krol, Magdalena M. "Implications of trichloroethylene diffusion through soil-bentonite slurry walls." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0019/MQ58050.pdf.
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Martin, Eric John. "Laboratory study evaluating electrical resistance heating of pooled trichloroethylene." Thesis, Kingston, Ont. : [s.n.], 2009. http://hdl.handle.net/1974/1723.
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Chard, Julie K. "Uptake and Transformation of Trichloroethylene by Hybrid Poplar: Laboratory Studies." DigitalCommons@USU, 1999. https://digitalcommons.usu.edu/etd/3647.
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Trichloroethylene (TCE) was widely used as an industrial solvent and degreasing agent for most of the twentieth century. It is now a widespread groundwater contaminant. Phytoremediation may be a cost-effective cleanup method for TCEii contaminated soils and groundwater. Studies of environmental TCE fate are complicated by its volatility. The literature repons both significant and insignificant plant uptake of TCE. Conflicting findings may be due to differences in exposure level, conditions, and duration of the studies, or to experimental artifacts from laboratory systems.
This research quantified plant uptake and volatilization of TCE using a unique laboratory system. Hybrid poplar trees were exposed to 1 or 10 ppm TCE over a 43-d period. [14C]TCE was added to four high-flow, aerated, hydroponic plant growth chamber systems designed to provide high mass recoveries, an optimal plant environment and complete separation between foliar and root uptake.
Transpiration stream concentration factors (TSCFs) for TCE, calculated from total [14C]TCE in shoot tissues plus phytovolatilized 14C, were 0.11 for two 1 ppm treatments and 0.15 for a 10 ppm treatment with roughly 25% attributed to phytovolatilization. Though extending study duration from 26 to 43 d resulted in accumulation of more mass of 14C in plant tissues, it had no effect on TSCF. These TSCF values are much lower than other published experimental values and values predicted by a theoretical relationship between TSCF and octanol-water partition coefficient. The TCE metabolites trichloroethanol (TCEt), trichloroacetic acid (TCAA), and dichloroacetic acid (DCAA)were identified in plant tissues of the 10-mg/L treatment.
Hybrid poplar uptake ofTCAA and TCEt was quantified using a simpler aerated hydroponic system. TSCF values were calculated based on extractable parent compound in shoot tiss ues. TSCF for TCEt was < 0.01. Presence of TCAA in hydroponic solution and in leaf and root tissues indicated transformation of TCEt to TCAA. TSCF for TCAA was < 0.03 and decreased with increasing exposure concentration. TSCF also decreased under oxygen-limited root-zone conditions. Presence of DCAA in leaf and root tissues indicated transformation ofTCAA to DCAA. Transformation of parent compound, coupled with low extractability, may contribute to low TSCFs.
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Stewart, Neil. "REACTION RATES FOR THE DEHALOGENATION OF TRICHLOROETHYLENE USING VARIOUS TYPES OF ZERO-VALENT IRON." Master's thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4273.
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Remediation of trichloroethylene (TCE) and other chlorinated solvents is of great concern due to their toxicity and their persistence in the environment. Iron has been used extensively in the past decade as a subsurface reactive agent for the remediation of dense, nonaqueous-phase liquids (DNAPLs). Permeable reactive barrier walls (PRBW) have been installed at many sites around the country to treat contaminated plumes resulting from the presence of DNAPL pools. The use of zero-valent metals, such as iron, to effectively reductively dechlorinate DNAPLs has been employed as the reactive material in these PRBWs (Gillham et al., 1993). However, limited work has been conducted to compare the kinetics of TCE degradation related to various manufacturing sources of iron and the pretreatment the iron receives prior to subsurface installation. Determination of iron reactivity through kinetic studies makes it possible to compare different types of iron and the effects that pretreatment has on reactivity. This research utilized rate studies, scanning electron microscopy, and BET surface area analysis for iron particles that were obtained from several sources. Peerless Metal Powders and Abrasive, Inc., Connelly-GPM, Inc., and Alfa Aesar Inc., produced the iron particles using various manufacturing techniques, and nanoscale iron was synthesized in our laboratory. By utilizing zero-headspace batch vial experiments and gas chromatography, changes in TCE concentration were determined. The data obtained produced linear first order rate plots from which dehalogenation rate constants were obtained. The rate constants were normalized by iron mass, solution volume, and surface area. The pretreatment techniques employed in this study, including ultrasonication and acid washing, demonstrated a beneficial effect by removing oxide precipitates from the iron surface, thus increasing the reactivity of the iron. Mass loading studies revealed how physical factors, associated with the experimental setup, could influence reaction rates. Surface area studies confirmed that the smaller iron particles, such as the nanoscale iron, have a greater surface area per unit mass. The large mass and volume normalized rate constant, kMV, obtained for the nanoscale iron was a result of this high surface area. However, the calculated surface area normalized rate constant, kSA, for the nanoscale iron was significantly lower than those for the granular iron samples tested. It was concluded that differences in surface area normalized rate constants, between different iron particle types, could be attributed to inherent characteristics of the iron, such as composition and crystal structure.M.S.
Department of Chemistry
Arts and Sciences
Industrial Chemistry
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Gu, Zhongchun April. "Assessment of reductive dechlorination of vinyl chloride and characterization of enrichments that grow on vinyl chloride as the sole carbon and energy source /." Thesis, Connect to this title online; UW restricted, 2003. http://hdl.handle.net/1773/10169.
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Hashimoto, Yemia Turnage, and Yemia Turnage Hashimoto. "Sorption isotherms of trichloroethylene to sand at varying moisture contents." Thesis, The University of Arizona, 1998. http://hdl.handle.net/10150/626777.
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The sorption of trichloroethlyene (TCE) vapors to low foe silica sand wetted at five
moisture contents (approximately 5.3, 9.2, 13.2, 17.2 and 21.2%) in stainless steel
columns was studied using three techniques: complete breakthrough curves, step-wise
desorption, and adsorption pulses. Distribution coefficients ~) were determined and
there is no trend with moisture content. ~ varied for the different techniques, with
complete breakthrough curves giving the most consistent values. These results also
indicate that desorption experiment protocols need further evaluation and that rate-limited
aqueous diffusion can bias adsorption pulse experiments. The results are inconclusive as
to whether the sorption isotherm is linear. Further research on aqueous sorption
coefficients at different concentrations is necessary to accurately define the isotherm
shape.
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Potter, Laura Kay. "Physiologically Based Pharmacokinetic Models for the Systemic Transport of Trichloroethylene." NCSU, 2001. http://www.lib.ncsu.edu/theses/available/etd-20010516-105855.
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Three physiologically based pharmacokinetic (PBPK) models for thesystemic transport of inhaled trichloroethylene (TCE) are presented.The major focus ofthese modeling efforts is the disposition of TCE in the adiposetissue, where TCE is known to accumulate. Adipose tissue is highly heterogeneous, with wide variations in fat cell size, lipid composition, blood flow rates and cellpermeability. Since TCE is highly lipophilic, the uneven distributionof lipids in the adipose tissue may lead to an uneven distribution of TCEwithin the fat. These physiological characteristics suggest that thedynamics of TCE in the adipose tissue may depend on spatial variations within the tissueitself.
The first PBPK model for inhaled TCE presented here is a system ofordinary differential equations which includes the standardperfusion-limited compartmental model for each of the adipose, brain,kidney, liver, muscle and remaining tissue compartments.Model simulations predict relatively rapiddecreases in TCE fat concentrations following exposure, which may notreflect the accumulation and relative persistence of TCE inside the fattissue. The second PBPK model is identical to the first except forthe adipose tissue compartment, which is modeled as a diffusion-limited compartment.Although this model yields various concentration profiles for TCE inthe adipose tissue depending on the value of the permeabilitycoefficient, this model may not be physically appropriate for TCE,which is highly lipophilic and has a low molecular weight. Moreover,neither of these two PBPK models is able to capture spatialvariation of TCE concentrations in adipose tissue as suggested bythe physiology.
The third model we present is a hybrid PBPK model with adispersion-type model for the transport of TCE in the adipose tissue. Thedispersion model is designed to account for the heterogeneities within fattissue, as well as the corresponding spatial variation of TCE concentrationsthat may occur. This partial differential equation model is based onthe dispersion model of Roberts and Rowland for hepatic uptake andelimination, adapted here for the specific physiology of adiposetissue.
Theoretical results are given for the well-posedness of a generalclass of abstract nonlinear parabolic systems which includes the TCEPBPK-hybrid model as a special case. Moreover, theoretical issues related to associated general least squares estimation problems are addressed,including the standard type of deterministic problem and aprobability-based identification problem that incorporates variability inparameters across a population. We also establish thetheoretical convergence of the Galerkin approximations used in our numericalschemes.
The qualitative behavior of the TCE PBPK-hybrid model is studied usingmodel simulations and parameter estimation techniques. In general, theTCE PBPK-hybrid model can generate various predictions of the dynamicsof TCE in adipose tissue by varying the adipose model parameters.These predictions include simulations that are similar to the expectedbehavior of TCE in the adipose tissue, which involves a rapid increaseof TCE adipocyte concentrations during the exposure period, followed by aslow decay of TCE levels over several hours.
Results are presented for several types of parameter estimationproblems associatedwith the TCE PBPK-hybrid model. We test theseestimation strategies using two types of simulated data: observationsrepresenting TCE concentrations from a single individual, andobservations that simulateinter-individual variability. The latter type of data, which iscommonly found in experiments related to toxicokinetics, assumesvariability in the parameters across a population, and may includeobservations from multiple individuals. Using both deterministic andprobability-based estimation techniques, we demonstrate thatthe probability-based estimation strategiesthat incorporate variability in the parameters may be best suited forestimating adipose model parameters that vary across the population.
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Keane, Paul. "The mechanism of trichloroethylene neurotoxicity and its relation to Parkinsonism." Thesis, University of Newcastle upon Tyne, 2013. http://hdl.handle.net/10443/2306.
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Parkinson’s Disease (PD) is a progressive neurodegenerative condition characterised by deterioration of the dopaminergic (DA) neurons of the substantia nigra pars compacta (SNpc). The exact mechanism by which SNpc cell death in PD occurs is poorly understood but several lines of evidence implicate both environmental and genetic factors. Trichloroethylene (TCE) is an industrial solvent used as a degreasing agent and in dry cleaning. TCE is a major environmental contaminant in the air, the water system and soil and is therefore exposed at low levels to various groups in the population. There have been links between chronic exposure to TCE and Parkinson-like symptoms reported and in vivo experiments support this link. It has also been discovered that TCE can be converted, via chloral, to a potentially DA neurotoxin TaClo in man. This project investigated this link between TCE and PD and to elucidate any causative mechanisms. Cellular exposure paradigms were used to show neurotoxicity of TCE, chloral and TaClo in DA neurons. The mechanism of this cell death in TaClo was found to be necroptotic - and not apoptotic - in nature and involve induction of autophagy, DNA damage and an increase in reactive oxygen species (ROS) in exposed cells. A possible source of this ROS was suggested with the findings that TaClo significantly inhibits Complex I of the mitochondrial oxidative phosphorylation chain - an effect known to produce superoxide - and an increase in mitochondrial ROS seen in cells following TaClo treatment. The cell death induced by chloral was found to follow a different path, with neither apoptotic or necroptotic characteristics observed in exposed cells, and Complex I only inhibited at high doses. However, chloral was found to block the reduction of cytochrome c at lower doses, a property that may be involved in the neurotoxicity seen with chloral. Animal models of TCE, chloral and TaClo exposure found no significant motor or cognitive abnormalities in behavioural testing of either wild-type mice or rats or human A30P mutated α-synuclein overexpressing mice. However, TCE and TaClo exposed wild-type and A30P mice did show a significant decrease in DA neuronal number and density in the SNpc, suggesting both compounds are neurotoxic to DA neurons in vivo. An LC-MS/MS assay was developed to assess neurotransmitter levels in the brains of toxin exposed animals, however the method was not found to be consistently accurate and showed extreme variability in results. In conclusion, the main results of this thesis suggest that TCE does lead to DA neurodegeneration in the SNpc of exposed individuals, probably through metabolism to the neurotoxic compound TaClo. The neurotoxic properties of TaClo are DA specific and relatively potent. The mechanism of neurotoxicity is hypothesised to be through inhibition of mitochondrial Complex I, inducing increased ROS production and damage of intracellular organelles, DNA and proteins, which in turn leads to the activation of autophagy and PARP activation. This intracellular stress instigates RIP1 mediated necroptosis and death of the cells.
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McClellen, Kristen Lee 1960. "Biodegradation of trichloroethylene by bacteria indigenous to a contaminated site." Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/191915.
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Bacteria indigenous to a trichloroethylene (ICE) contaminated site were used in a batch-microcosm experiment to determine their ability to grow in the presence of and degrade ICE. At two different initial concentrations of ICE, bacterial populations were able to increase their number by two orders of magnitude. Under the aerobic, oligotrophic conditions of the microcosms, the average ICE disappearance in live microcosms for all samples was 47 percent and 33 percent when the initial concentration was 559 ppb and 6.7 ppm, respectively. No TCE disappearance was observed in blank or killed microcosms. It is believed that bacteria degraded ICE to levels as low as 1-2 percent of the initial concentration. Lag times of 14 and 18 days, were observed for the low- and high-concentration microcosms, respectively. Bacterial population shifts were noted throughout the experiment. None of the volatile chlorinated compounds expected as products of biodegradation were found.
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Winters, Rachel Melanie. "Volatilization of Trichloroethylene from Shallow Subsurface Environments: Trees and Soil." DigitalCommons@USU, 2008. https://digitalcommons.usu.edu/etd/48.
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Results from two previous studies conducted at Operable Unit 2 (OU2) of Hill Air Force Base, Utah indicate that the phytovolatilization (volatilization from leaves and trunk) of TCE by indigenous trees as well as soil surface flux may play a significant role in the removal of TCE from shallow groundwater plumes around the base. Previous studies investigated late summer and early autumn TCE leaf volatilization but no attempt was made to examine potential TCE volatilization seasonal variability and the volatilization of TCE directly from tree trunks. Whole tree transpiration rates were also not directly measured. To address those limitations and improve removal estimates, TCE removal via volatilization from leaves and tree trunks at OU2 was measured monthly during a growing season. Sap flow sensors were installed in several representative trees to directly measure transpiration rates. Transpiration rates were estimated between 15 and 160 L/day by sap flow meter data collected in 2007 and 2008. With an average growing season of 150 days, estimated TCE loss to the atmosphere through leaf volatilization was 107 to 211 mg/tree/year. An additional 4.1 mg/tree/year was estimated to volatilize directly from tree trunks. No definite seasonal trends in phytovolatilization were observed. Soil surface flux over 12,200 m2 equated to an overall loss of 390 g/year (180 days per year), with combined losses from all volatilization pathways of a maximum of 424 g/year, assuming an estimated 30 trees. This was one-sixth the removal of the interceptor trench installed in 1997, which is significant considering there was no additional cost for natural attenuation removal. Tree cores, branches, groundwater, precipitation, and nearby canal samples were collected to analyze for stable isotopes of hydrogen and oxygen. Stable isotope results, low summer precipitation, and TCE core sample concentrations suggest that the trees are using shallow groundwater as their primary source of water. There was no indication of any significant yearly or seasonal variability in TCE leaf and trunk volatilization, groundwater concentrations, and groundwater use by trees.
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Nunes, Jack D. "An Exploratory Study of the Systemic Effects of Lead, Trichloroethylene, and a Mixture of Lead and Trichloroethylene Provided Concurrently by Oral Gavage to Male Rats." Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/40927.
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Forty rats, in groups of ten, were orally dosed with corn oil, corn oil and 2,000 mg/kg trichloroethylene (TCE), corn oil and 2,000 mg/kg lead carbonate, or a mixture of 2,000 mg/kg each TCE and lead carbonate, in an effort to determine whether or not dual administration of both TCE and lead would have an additive effect on neurotoxicity and overall health as indicated by behavioral and physiologic measurements and tissue pathology. A functional observational test battery (FOB) was performed before, during, and after dose administration to assess dose-related changes. The FOB testing assessed behavioral and physiologic measurements such as gait, open field activity, posture, grip strength, and handling reactivity. Pathological examination included assessing dosing related changes in the testis, spleen, heart, liver, kidney-adrenals, and brain.
Results indicated that each compound was toxic individually, and that the combination of the two neurotoxicants provided conflicting indications of both reduced and additive toxicity. The toxicity of lead carbonate caused the vast majority of toxic consequences in the study. A reduction in body weight and an increased resistance to cage removal were the only statistically significant changes observed in the FOB that were due to concurrent administration of lead and TCE. Organ-to-body weight and organ-to-brain weight calculations showed evidence of a statistical difference between the lead and lead/TCE dosed animals for liver, kidney-adrenals, and body weight. The significance of these changes is not fully understood.Master of Science
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Jiang, Zhen. "An investigation of the neurotoxicity of trichloroethylene and its metabolite TaClo." Thesis, University of Newcastle upon Tyne, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.490130.
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rricrJoroethylene (rCE) is a nonflammable liquid with a high vapour pressure that is primarily used in industry as a metal degreasing agent and is stable for many years. It has moderate solubility in water and can leach from soils into groundwater and therefore water mId food ingestion can be a route of exposure for the general population and illi~alation occupationally. A clinical observation of patients with multiple system atrophy (MSA) suggested an associated with occupational exposure to TCE. Clinical exposure to TCE has recently been proposed to be a possible pathogenic factor in the onset of Parkinson's disease (PD) (Bringmann et aI, 2001) and other neurodegenerative disorders. A mechanism has been indentified in rodents where chloral a metabolite of TCE combined \vith endogenous tryptamine to produce 'TaClo' which, by structural similarities to known neurotoxic compounds, had the potential to be toxic to dopaminergic neurons in the extrapyramidal tracts (Bringmann et aI, 200Gb). Trichloroethylene metabolism to chloral by rat liver subcellular fractions (microsomal and S9) was investigated by GC-ECD. TCE metabolism to chloral showed a biphasic profile. The low capacity high affinity component may be important at occupational and environmental level of TCE exposure. The local TCE metabolism to chloral also was detected using rat brain substania nigra. Although the chloral formation in rat brain (O.05nmol/ g tissue/hour) was much lower than liver (1644nmol/g tissue/hour), local formation may contribute to neurotoxicity. Human CYP2El had a higher capacity to metabolism TCE than other CYP isoforms at high and low TCE concentrations. TaClo was chemically synthesized by reacting tryptamine with chloral (Bringmann, 1990). TaClo was also formed from tryptamine and chloral in buffer and in the presence of cells in vitro, which support its non-enzymatic formation in vitro and in vivo (Bringmann et aI., 2002b). TaClo uptake and efflux from cells was investigated in SH-SY5Y cells. It was found that Na dependent uptake was about three times higher than Na free uptake. Dopamine and OCT2 transporters expressed in oocytes showed little uptake of TaClo and OCTN2 may contribute to uptake of TaClo. TaClo was not transported out of the cell. TaClo selectively inhibited mitochondrial complex I activity and inhibited neuron dendrite outgrowth both indicating apoptosis and neurotoxicity. These results indicated that TaClo can be formed in biological system and be neurotoxic. TaClo and possibly a direct effect of TCE metabolism may induce oxdative stress in neural cells. These observations in vitro support the hypothesis that exposure to TCE may be associated in some individuals with development of neurodegenerative diseases such as MSA and Parkinsonism.
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MOSER, ADRIANE. "ESTIMATING HISTORICAL TRICHLOROETHYLENE EXPOSURE IN A URANIUM ENRICHMENT, GASEOUS DIFFUSION PLANT." University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1121362546.
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Berdanier, Bruce William. "Biosorption of 1,2,3,-Trichloropropane and Trichloroethylene by the Diatom Thalassiosira Pseudonana /." The Ohio State University, 1995. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487861796817653.
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Kalimtgis, Konstandinos. "ADSORPTION OF TRICHLOROETHYLENE AND CARBON TETRACHLORIDE ON SYNTHETIC AND NATURAL ADSORBENTS." Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/275355.
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Boving, Thomas Bernhard. "Performance and simulation of chemically enhanced solubilization and removal of residual chlorinated solvents from porous media." Diss., The University of Arizona, 1999. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_1999_154_sip1_w.pdf&type=application/pdf.
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Ju, Xiumin. "Reductive Dehalogenation of Gas-phase Trichloroethylene using Heterogeneous Catalytic and Electrochemical Methods." Diss., Tucson, Arizona : University of Arizona, 2005. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu%5Fetd%5F1366%5F1%5Fm.pdf&type=application/pdf.
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Ervin, Jared S. "Changes in Hybrid Poplar Endophytic Microbial Diversity in Response to Trichloroethylene Exposure." DigitalCommons@USU, 2010. https://digitalcommons.usu.edu/etd/638.
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Remediation of trichloroethylene (TCE) is a major priority for many contaminated sites all over the industrialized world including Hill Air Force Base, UT (HAFB). Phytoremediation as part of a cleanup strategy is an appealing option, and trees at HAFB have been studied to this end. Trees have also been used to delineate groundwater plumes because the passive uptake of organic contaminants by trees generally results in a direct relationship between tree and groundwater TCE concentrations if the trees are using the contaminated groundwater. However, the concentrations of plant-produced TCE metabolites can vary greatly. It was hypothesized that the endophytic microbial community present may be affecting the fate of TCE within these trees. This study was designed to determine if the microbial community present within hybrid poplar trees would change in response to TCE exposure. Trees were grown in a greenhouse to reduce environmental variability. Concentrations of TCE, its degradation products, and its metabolites were then measured in these trees. DNA was extracted from the tree tissues and amplified to determine the quantity of microbial DNA. Diversity of this DNA was determined by fragment analysis. Data were analyzed to determine if there was an effect of TCE treatment on the microbial community composition in the trees. Results showed that all tissues of dosed trees contained TCE. Metabolism of TCE to trichloroacetic acid (TCAA) and trichloroethanol (TCEtOH) in tree tissues was observed by the accumulation of these metabolites. Microbial DNA results revealed that TCE treatment reduced both the quantity and diversity of endophytic bacteria and fungi in several cases. Multivariate statistical analyses also showed that the endophytic microbial community shifted in response to TCE treatment. The endophytic microbial communities present in the hybrid poplar trees of this study were high in concentration and diversity, both of which were affected by TCE treatment. Endophytic bacterial concentrations were observed at over 109 copies/g with diversities of 70+ genetically distinct organisms. Decreases in these values with the addition of TCE showed that the community dramatically changed in some cases, but was able to more quickly adapt to TCE addition in other cases. The effects of these endophytic microorganisms associated with plants should therefore be included when phytoremediation is considered.
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Park, Chanjae. "Microbial anaerobic respiration of perchlorate with the presence of either high salinity or reductive dechlorinaton of trichloroethylene." abstract and full text PDF (free order & download UNR users only), 2005. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3210299.
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Padmanabhan, Anita Rema. "Novel Simultaneous Reduction/Oxidation Process for Destroying Organic Solvents." Digital WPI, 2008. https://digitalcommons.wpi.edu/etd-theses/465.
Full textAbstract:
Trichloroethylene (TCE) is one of the most common groundwater pollutants in the United States and is a suspected carcinogen. The United States Environmental Protection Agency (EPA) estimated that between 9% and 34% of the drinking water sources in the United States may contain TCE, and have set a maximum contaminant level of 5 ìg/L for drinking water. Traditional treatment technologies such as granular activated carbon and air stripping have only had marginal success at removing TCE from contaminated sites. Chemical oxidation processes have provided a promising alternative to traditional treatment methods. The objective of this research was to examine the conditions under which zero valent iron (Fe0) activates persulfate anions to produce sulfate free radicals, a powerful oxidant used for destroying organic contaminants in water. With batch experiments, it was found that persulfate activated by zero valent iron removed TCE more effectively than persulfate oxidation activated by ferrous iron. This laboratory study also investigated the influence of pH (from 2 to 10) on TCE removal. TCE was prepared in purified water and a fixed persulfate/TCE molar ratio was employed in all tests. The results indicated that this reaction occurred over a wide range of pH values. The production and destruction of daughter products cis 1,2 dichloroethylene and vinyl chloride were observed. The effect of persulfate dose on this reaction was also studied. Results showed that a molar ratio of 10/1/1 (persulfate/ZVI/TCE) yielded over 95 percent TCE destruction. Increasing the persulfate dose resulted in greater TCE destruction as well as destruction of the daughter products. Kinetic experiments at a molar ratio of 10/1/1 (persulfate/ZVI/TCE) show that approximately 90 percent of the TCE was destroyed in less than 15 minutes.
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Sheremata, Tamara W. "The influence of soil organic matter on the fate of trichloroethylene in soil." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0017/NQ44582.pdf.
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Xu, Jian. "SYNTHESIS AND REACTIVITY OF MEMBRANE-SUPPORTED BIMETALLIC NANOPARTICLES FOR PCB AND TRICHLOROETHYLENE DECHLORINATION." UKnowledge, 2007. http://uknowledge.uky.edu/gradschool_diss/561.
Full textAbstract:
Nanosized metal particles have become an important class of materials in the field of catalysis, optical, electronic, magnetic and biological devices due to the unique physical and chemical properties. This research deals with the synthesis of structured bimetallic nanoparticles for the dechlorination of toxic organics. Nanoparticle synthesis in aqueous phase for dechlorination studies has been reported. However, in the absence of polymers or surfactants particles can easily aggregate into large particles with wide size distribution. In this study, we report a novel in-situ synthesis method of bimetallic nanoparticles embedded in polyacrylic acid (PAA) functionalized microfiltration membranes by chemical reduction of metal ions bound to the carboxylic acid groups. Membrane-based nanoparticle synthesis offers many advantages: reduction of particle loss, prevention of particle agglomeration, application of convective flow, and recapture of dissolved metal ions. The objective of this research is to synthesize and characterize nanostructured bimetallic particles in membranes, understand and quantify the catalytic hydrodechlorination mechanism, and develop a membrane reactor model to predict and simulate reactions under various conditions. In this study, the PAA functionalization was achieved by filling the porous PVDF membranes with acrylic acid and subsequent in-situ free radical polymerization. Target metal cations (iron in this case) were then introduced into the membranes by ion exchange process. Subsequent reduction resulted in the formation of metal nanoparticles (around 30 nm). Bimetallic nanoparticles can be formed by post deposition of secondary appropriate metal such as Pd or Ni. The membranes and bimetallic nanoparticles were characterized by: SEM, TEM, TGA, and FTIR. A specimen-drift-free X-ray energy dispersive spectroscopy (EDS) mapping system was used to determine the two-dimensional element distribution inside the membrane matrix at the nano scale. This high resolution mapping allows for the correlation and understanding the nanoparticle structure, second metal composition in terms of nanoparticle reactivity. Chlorinated aliphatics such as trichloroethylene and conjugated aromatics such as polychlorinated biphenyls (PCBs) were chosen as the model compounds to investigate the catalytic properties of bimetallic nanoparticles and the reaction mechanism and kinetics. Effects of second metal coating, particle size and structure and temperature were studied on the performance of bimetallic system. In order to predict reaction at different conditions, a two-dimensional steady state model was developed to correlate and simulate mass transfer and reaction in the membrane pores under convective flow mode. The 2-D equations were solved by COMSOL (Femlab). The influence of changing parameters such as reactor geometry (i.e. membrane pore size) and Pd coating composition were evaluated by the model and compared well with the experimental data.
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Caldwell, Patricia Theresa. "Investigations into the Molecular Mechanisms of Trichloroethylene Cardiotoxicity in vivo and in vitro." Diss., The University of Arizona, 2009. http://hdl.handle.net/10150/195364.
Full textAbstract:
Trichloroethylene (TCE) is among the most common water contaminant in the United States and around the world. It is estimated that between 9% and 34% of all drinking water sources contain some TCE. The EPA set a drinking water standard for TCE at 5 parts per billion (ppb) in 1989, however since this date, many studies have shown TCE is dangerous to the health of adults and unborn children, even at low-level exposures. These studies reveal exposure to TCE can cause multi-organ damage, especially for the kidney, liver, reproductive and development systems. We investigated how TCE can effect embryonic heart development by identifing possible target mechanisms changing after exposure. Acute and chronic exposure to rat cardiomyocytes produced altered calcium flow and significant changes with TCE doses as low as 10ppb. Embryonic carcinoma cells, rat cardiomyocytes and fetal heart tissue all showed global changes in gene expression after low-dose TCE exposure, including critical ion channels that drive calcium flux. High levels of folic acid supplementation in combination with 10ppb TCE exposure in maternal diets caused significant genetic modifications in mRNA expression levels of Day 10 embryonic mouse cardiac tissue. We also found both high and low folate maternal diets leads to similar phenotypic outcomes in embryo development.
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Della, Vedova Luca. "Biofiltration of industrial waste gases in trickle-bed bioreactors - Case study: trichloroethylene removal." Doctoral thesis, Università degli studi di Padova, 2008. http://hdl.handle.net/11577/3425084.
Full textAbstract:
Trichloroethylene (TCE) is a very common air pollutant which has shown some characteristics that make its biodegradation particoularly stiff. TCE removal has been here exploited using a pilot-scale biotrickling filter operating counter-current and with a mixed compost-inert carrier bed. Bioreactor operated for longer than four months obtaining a maximum elimination capacity of 3.17 g/(m3h) and a removal efficiency between 50 and 85%.
Pressure drop and pH inside the bed remained constant during the test not affecting bioreactor performance. Using both organic and inert carrier has likely reduced bed compaction and carrier acidification. Data of elimination capacity were fitted using an original Ottengraf-modified model for the steady state conditions.
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Sharma, Sachin. "Slurry test evaluation for in-situ remediation of TCE contaminated aquifer." Worcester, Mass. : Worcester Polytechnic Institute, 2006. http://www.wpi.edu/Pubs/ETD/Available/etd-082306-124940/.
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Yen, Chia-Wen, and 顏嘉玟. "Study of trichloroethylene biodegradation." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/28883542600744107202.
Full textAbstract:
碩士國立清華大學
化學工程學系
89
Biofiltration was successful applied to treat volatile organic compounds (VOCs) from contaminated air streams. The experimental approach involved operating a bench-scale biofilter with using granular activated carbon as supports. There was no inoculation and only microorganisms indigenous to the bed medium were used throughout the whole process. Trichloroethylene (TCE) was degraded cometabolically with toluene as primary carbon source. In our work, we investigated that TCE is a potent competitive inhibitor of toluene oxidation because it competed with toluene for oxidation by the enzyme of toluene dioxygenase (TDO). Above a toluene concentration of 0.3 g/m3, the TCE removal efficiency decreased. In turn, TCE existing always decreased the toluene elimination capacity. Under steady-state, at 3 mines-gas-retention time and at 25℃, we get an optimum operation : removal efficiency of toluene and TCE are 70% and 90%.
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Hsu, Han-Hsuan, and 許漢軒. "The Catalystic Incineration of Trichloroethylene." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/08085760183727852915.
Full textAbstract:
碩士國立成功大學
環境工程學系
88
The Catalystic Incineration of Trichloroethylene over Mn2O3/γ-Al2O3 Catalyst Graduate St. Han-Hsuan Hsu Advisor：Hsin Chu Abstract Volatile organic compounds (VOCs) are the typical pollutants emitted from the petrochemical industrial processing. They can easily release radicals to react with some chemical compounds, such as NOx and Ozone in the atmosphere, to form the photochemical smog. Hence, VOCs are the main targets to prevent air pollution from the petrochemical industry. Trichloroethylene (TCE) decomposed over Mn2O3/γ-Al2O3 catalyst in the fixed bed reactor was conducted in this study. The explanation of results can be divided into four major parts. 1.We use three catalysts, including Mn2O3/γ-Al2O3, NiO/γ-Al2O3, Pt/γ-Al2O3 to incinerate Trichloreothylene and find that the Mn2O3/γ-Al2O3 catalyst has the best conversion for Trichloroethylene. 2.We employ some instruments, such as XRD, BET, SEM and EDS, to determinate the characteristics of the catalysts after impregnated, calcined and reduced. We can get the best catalytic crystal while the calcination temperature is 600℃ and the calcination time is 8 hours. We also find catalytic pore shape is not changed very much by calcination. The catalytic pore shape of the catalysts are all like “ink bottle” after impregnated,calcined and reduced. 3.The effects of operating factors, such as inlet temperature, space velocity, VOCs inlet concentration, and oxygen concentration on the catalytic incineration of TCE were performed. The results show that conversion of TCE increases as inlet temperature and oxygen concentration increase, and decreases with the increasing of TCE concentration and space velocity. We also find that a intermediate, C2Cl4, is formed in the process of reaction. 4.The activity of the catalyst decreases significantly while TCE incineration is operating under a low temperature (365℃). However, the activity of the catalyst does not change much while TCE incineration is operating under a high temperature (500℃). We employ some instruments, such as EA, XRD, EDS, SEM, mapping and BET, to determinate the characteristics of the catalysts after incineration. We find the factor of catalytic incineration are not due to “coke”, the last catalytic crystal becomes Mn2O3, the Cl element is in the surface of catalysts, the elemental duspersion and intensive of Al and Mn decrease, and the catalytic pore shape of catalysts are all like “ink bottle” after incineration.
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lin, Chin-lung, and 林金龍. "Biodegradation og trichloroethylene in saline environment." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/84728959090743223558.
Full textAbstract:
碩士國立海洋大學
河海工程學系
90
Two chemostat reactors were used to cultivate phenol oxidizing bacteria in this study, where one reactor was seeded with sludge from wastewater treatment plant of a food company and continuously fed with phenol dissolved in distilled water ( bacteria obtained from this reactor was called salinity-free water phenol oxidizers , SFPOxidizers), the other reactor was seeded with seawater from Keelung Port and continuously fed with phenol dissolved in solution containing 3.6% salinity (bacteria obtained from this reactor was called HP oxidizers , HPOxidizers). The aim of this study is to clarity the biodegradation characteristics of trichloroethylene (TCE) by these two kinds of bacteria in saline environments. The experiment consists of four phases. The first phase is to estimate the specific oxygen uptake rate (SOUR) of these two bacteria degrading phenol, betaine, toluene, TCE, and sucrose, respectively. The second phase is to study the effect of supplement of betaine, toluene, or sucrose to TCE on biodegradation of TCE. The third phase is to study the competitive inhibition between toluene and TCE in solutions with salinity. The forth phase is to study the effect of chloride on biodegradation of TCE in saline solutions. From the result of experiment, it is found that SOUR could be an indication to reflect the biodegradability of substrates. The SOURs of SFP Oxidizer-degrading phenol, toluene, sucrose and betaine (all in 2 mg/L) are 124, 31.3, 7.0, and 7.0 mg-O2/hr-gVSS, respectively. In addition, the SOURs of HP oxidizers are larger than that of SFP oxidizers in resting cells condition. To try to enhance TCE biodegradation, toluene, betaine, or sucrose was separately supplemented to TCE solutions containing 3.6 % salinity. Result shows these compounds failed to enhance the biodegradation of TCE. Toluene can be used a growth-substrate to SFP oxidizer in fresh water environment, but toluene cannot be utilized by HP oxidizer in 3.6 % saline solutions. The result of the third phase clarifies the competitive inhibition between toluene and TCE in solution with various salinity. The supplementation of toluene decreases the biodegradation rate but increases the mass of TCE removed when the salinity is below 1%. When the salinity is above 2.5%, the biodegradation rate of toluene will decrease with increasing salinity, and the enhancement of biodegradation of TCE become limited. In the forth phase, NaCl and Na2SO4 were used to prepare salinity solutions to test the effect of chloride on biodegradation of TCE. Result shows similar inhibition for TCE biodegradation occurred in these two saline solutions, so chloride was not the critical factor in inhibiting TCE biodegradation .
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Cheng, Shung Ren, and 鄭舜仁. "Biodegradation of Trichloroethylene by Phenol-oxidizing." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/32532601758466283829.
Full textAbstract:
碩士國立屏東技術學院
環境工程技術研究所
85
This research uses two laboratory-scale chemostats and one rotating biological contactor , operated at solids retention time (SRT) of 4 days、20 days and 72 days, respectively, to cultivate different consortium of phenol bacteria. Comparisons then are performed with these three types of bacteria: oxygen uptake rates, responses to the toxicity of trichloroethylene, and the degradation rates and extent of trichloroethylene. As obtained data are subject to Haldane kinetic analysis, results show that the maximum specific oxygen uptake rates (SOURm) for bacteria with 4 days、20 days and 72 days of SRT are 445、110 and 108 mg O2/g VSS-hr, respectively; furthermore, half velocity coefficients are 15、0.45 and 2 mg/L and inhibition coefficients are 60、138 and 25 mg/L, respectively. Trichloroethylene toxicity to these three bacteria is found insignificant at the dosage of 2 mg/L, but when the dose of tricholoethylene is up to 20 mg/L oxygen uptake rates are depressed in some degree, due to intermediate products produced during degrading tricholoethylene. As the responses of different bacteria to the same dose of tricholoethylene are compared, it reveals that the longer the operating solids retention time is, the lower the oxygen uptake rate bacteria have; this result implies that the bacteria are more susceptible to the toxicity than the young one. For degrading tricholoethylene, the bacteria with 4 days have higher degradation rate than that the bacteria with 20 and 72 days have. At resting cells conditions, the value of k for bacteria with 4 days of SRT is 0.6 mg TCE/mg VSS- day, while that for 20 days and 20 days bacteria are 0.14 and 0.00003 mg TCE/mg VSS-day. This result further indicates that solids retention time is an important parameter for determining activity of bacteria; in degrading tricholoethylene, at longer solids retention time the bacteria will become less active.
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Kuan, Chih-Hsien, and 官知嫺. "Cometabolism of trichloroethylene by aromatic-utilizing microorganisms." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/10435559358560636065.
Full textAbstract:
碩士國立中興大學
環境工程學系
86
Due to the specific properties in physics and chemistry, tri- chloroethylene(TCE) is widespreadly used in industry. However, accident spill and unsuitable disposal often result in the pollution of soil and groundwater by TCE, one of the chlorinated compounds. The chlorinated compounds may exist in the environment for a long time due to the low degradation rate. Among the biological, physical and chemical treatment processes, biological treatment is more preferred because of the low operation cost and other benefits. Because the biodegradation of TCE produces toxic intermediates in the anaerobic environment and because TCE is not biodegraded by aerobic microbes, cometabolism becomes the only way to aerobically remove TCE. Microorganism communities that degrad aliphatic compounds have been investigated for a long time, especially in the cometabolism of chlorinated organic compounds. In this report, microbes that degrad toluene or phenol were isolated and appraised the cometabolic capacity by batch experiments. The strain that showed acceptable cometabolic capacity was then determined its appropriate conditions to be applied in the contaminated site. As a result, two isolated strains that degraded toluene demonstrated cometabolic capacities. However the degradation rates were relatively lower. The addition of toluene was not able to cometabolize TCE completely. On the other hand, two isolated strains can use phenol as the only substrate. These two strains decreased pH in the environment when phenol was degraded in quantity. One of the two strains shows a significantly cometabolic capacity. This strain continued to cometabolize TCE even phenol was completely degraded. The lowest phenol/TCE ratio approaches to 20, but the ratio that approaches to 125 is better in the consideration of degrading time. Furthermore, when the concentration of TCE is 0.0913 μ mole/bottle (800 μg/L), the neutral pH was maintained with higher phenol/TCE ratio (125). In addition, the highest concentration of TCE that can be cometabolized is more than 3.65 μ mole/bottle(32000 μg/L). However, the high TCE concentration not only was cometabolized very slowly, but also not completely removed.
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Chen, Zhi Rng, and 陳志榮. "Surfactant-Enhanced Removal of Trichloroethylene from Groundwater." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/52589242036535974657.
Full textAbstract:
碩士國立屏東科技大學
環境工程與科學系
91
Organic solvents are widely used in chemical manufacturing processes. Those solvents possibly leaked into soil and further contaminated the underground aquifer. Traditional soil remediation technology, such as soil vapor extraction (SVE) and pump-and-treat technique, has several restrictions and their remediation efficiencies are not promising. Traditional soil remediation techniques can not meet the strict environmental regulations due to their selectivity to the pollutant types, characteristics, and contaminated sites. The surfactant flushing technology is developed and often utilized to remediate the contaminated aquifers. When the surfactant is injected into aquifers, the DNAPLs are trapped into the hydrophobic center of the micelles formed by the surfactant monomers, and thus the solubility of the DNAPLs is increased. The surfactants used for in-situ chemical flushing are typically non-ionic or anionic, because cationic surfactants tend to be adsorbed onto the surface of the negatively charged soil particles. Non-ionic surfactants are more desirable because they possess lower critical micelle concentration (CMC) and are not liable to flocculate clay particles in the soil. This research utilized the anion and non-ionic surfactant solutions to flush the soil column filled with quartz or aquifer sands that were polluted by trichloroethylene (TCE). The remediation efficiencies of three surfactants to TCE removal were evaluated. The anion surfactant applied in this study was sodium dodecyl sulfate (SDS), and the non-ionic ones were Tween 80 and Triton 100, respectively. In addition, groundwater was also used to flush the quartz and aquifer sands to compare the removal efficiencies that were flushed by different surfactants. The experimental results showed that the emulsion degree of three surfactants in the phase behavior runs was SDS > TX-100 > Tween80. The results regarding both flushing aquifer and quartz sands revealed that the flow rate in flushing aquifer sands was similar to that in flushing quartz sands. Moreover, the flow rate reached the maximum at the first pore-volume collection, it decreased or reached steady state condition with the following sample collection. For 1% and 3% of TCE in coarse and fine quartz sand, the recovery efficiencies of TCE with 1% of flushing agents were TX-100 > Tween 80 > SDS > groundwater in sequence; while for 1% and 3% of TCE in coarse and fine aquifer sand were Tween 80 > TX-100 > SDS > groundwater in sequence. The pulse-flushing technique not only decreased the dosage of surfactant but also increased the flow rate as well as the TCE removal efficiency. The results from ultrafiltration experiments showed that ultrafiltration membranes with pore sizes of 10,000 and 1,000 daltons could effectively retain the majority of the surfactant and TCE. The rejection ratio of TX-100 (1%) and TCE (1% and 3%) with membrane pore size of molecular-weight-cut-off (MWCO) = 1,000 Daltons were better than those with MWCO = 10,000 Daltons. It is expected that the data obtained in this study can be utilized on the design and evaluation of soil flushing technique for remediation of the DNAPLs contaminated aquifers.
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Yeager, Chris M. "Physiological consequences of trichloroethylene degradation by the toluene-oxidizing bacterium Burkholderia cepacia G4." Thesis, 2001. http://hdl.handle.net/1957/32414.
Full textAbstract:
A number of bacterial species are capable of degrading the widespread environmental
pollutant trichloroethylene (TCE) via aerobic cometabolism, but cytotoxic effects that
can debilitate the microorganism often accompany this transformation. In this
dissertation the effects of TCE degradation on the well-studied, toluene-oxidizing
bacterium Burkholderia cepacia G4 were investigated at the physiological and genetic
level and compared and contrasted to the effects elicited by several nonhalogenated,
short chain alkenes and alkynes. Linear alkynes (C���-C������) were classified as strong
mechanism-based inactivators of toluene 2-monooxygenase activity in B. cepacia G4,
with 2- and 3-alkynes providing a more potent effect than their 1-alkyne counterparts.
The C��� alkyne, acetylene, was weak inactivator of toluene 2-monooxygenase activity
presumably because it does not bind efficiently to this oxygenase. Toluene-grown cells of B. cepacia G4 cells oxidized ethylene and propylene to their respective
epoxides with no observable effect on cell culturability or general respiratory activity.
In contrast, TCE oxidation was accompanied by a myriad of cytotoxic effects.
Accumulation of general cellular damage, manifested as a loss of cell culturability and
general respiratory activity, outpaced loss of toluene 2-monooxygenase activity during
TCE oxidation. Measures of the culturability of TCE-injured cells varied up to 3
orders of magnitude (depending on the method of assessment), and it was found that
TCE-injured cells were ultra sensitive to H���O��� on the surface of agar plates. It was
proposed that a toxicity threshold exists for B. cepacia G4 during TCE oxidation, and
once cells have degraded ���0.5 ��mol of TCE (mg of cells�����) the likelihood of recovery
decreases significantly. Tn5 mutants of B. cepacia G4 with disruptions in genes
putatively encoding enzymes involved in DNA repair (including UvrB, RuvB, RecA,
and RecG) were ultra susceptible to killing by TCE, as well as the known DNA
damaging agents, UV light, mitomycin C, and H���O���. Physiological and genetic
analysis of the mutants provided suggestive evidence that nucleotide excision repair
and recombinational repair activities are linked to the survivability of TCE-injured B.
cepacia G4.Graduation date: 2002
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Lee, Mao Shan, and 李茂山. "Bioremediation of 2,4-dichlorophenol- and trichloroethylene- contaminated soil." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/63495326796015280880.
Full textAbstract:
碩士國立中興大學
環境工程學系
86
ABSTRACT This study focused on the bioremediation in soil contaminated by chlorinated hydrocarbons. The application of supercritical fluid extraction (SFE) on the nonvolatile organic compound from soils was also discussed. The target compounds of this study were 2,4-dichlorophenol (2,4-DCP) and trichloroethylene (TCE). These compounds are the most commonly pollutants in the environment and are used as chlorinated aromatic compound and chlorinated aliphatic compound in this study, respectively. The experimental r
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湯君田. "Catalytic Incineration of Trichloroethylene by ZnO/Al2O3 Catalyst." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/84483491211995315564.
Full textAbstract:
碩士弘光科技大學
環境工程研究所
94
Abstract Trichloroethylene (TCE) is a volatile and nerve-toxic liquid, which is widely used in many industries as an organic solvent. Without proper treatment, it will be volatilized into the atmosphere easily and hazardous to the human health and the environment. Catalytic incineration has been a popular and alternative technology for the treatment of VOCs due to its lower operatior temperature and has high removal efficiency. This study tried to prepare granular ZnO/Al2O3 catalysts with a modified oil-drop sol-gel process incorporated the incipient wetness impregnation method. The conversions of TCE by these granular ZnO/Al2O3 catalysts and the effects of different preparation and operation conditions were investigated. In addition, the reaction products and catalyst characteristics were analyzed by FTIR, SEM, EDS, XPS, BET, and GC/MS to figure out the pathway of catalytic reactions and the reasons of catalyst decay. Experimental results showed that the granular ZnO/Al2O3 catalyst had good catalytic performance and surface characteristics. ZnO/Al2O3(N) catalyst had better performance than ZnO/Al2O3(O) at high operation temperature. With 10% active metal concentration, 550 oC calcination temperature, 450 oC operation temperature and 18000 hr-1 space velocity, the ZnO/Al2O3(N) catalyst had the best TCE conversion 98%. Higher calcinations temperature caused the catalyst sintered and decreased BET surface areas. The conversions of TCE were increased with the concentration of active metal and reaction temperature, and were all higher than 90% regardless the oxygen concentration in the feed gas. The major reaction products during catalytic decomposition of TCE by ZnO/Al2O3(N) catalyst were CO2, H2O, HCl, and Cl2. The BET surface areas of catalysts were significantly decreased at higher calcination and operation temperatures due to the sintering of catalyst materials and the accumulations of reaction residua. The ZnO/Al2O3(N) catalyst had longtime and stable catalytic activity, it can be operated for at least 12 hours and the conversions of TCE were still higher than 95%. Moreover, three kinetic models of heterogeneous catalysis were used to evaluate experimental results and found that Mars and Van Krevelen Model was more suitable applicable for the catalytic incineration of TCE by ZnO/Al2O3(N) catalyst.
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Tsai, Shen-Long, and 蔡伸隆. "Cometabolic Degradation of Trichloroethylene by A Toluene-Oxidizer." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/39227299502273486373.
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Huang, Sue-Ching, and 黃琡晴. "Photocatalytic Degradation of Gasous Trichloroethylene with UV/TiO2." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/62898151229517883056.
Full textAbstract:
碩士國立臺灣大學
環境衛生研究所
89
Environmental pollution, including pollution in occupational setting generated in industries has been of important concern. Because of the adverse health effect, researchers had been interested in the photocatalysis of volatile organic compounds (VOCs) using UV/semiconductor. Using low energy ultraviolet light heterogeneous photocatalysis can excite electron/electron hole pairs, and release hydroxide free radicals, in a serial of chain reactions, to decompose VOCs in to CO2 by oxidation. This technology was of interest because of several advantages. For this study, we designed a photocatalysis chamber consisted of nineteen UV lamps (368nm wavelength, d=4.1mm, length=19cm) coated with TiO2 as catalyst. A serial of tests were conducted for photocatalysis to determine the best initial concentration of trichloroethylene, retention time, reaction temperature, and effects of humidity. We measured the levels of degradation and mineralization of trichloroethylene, and evaluated light efficiency as well. The system was able to remove trichloroethylene in a conversion rate of greater than 95%, with the maximum reaction rate of 9.713 mmole/s-g, and the maximum quantum yield of 0.315. When the flow rate of air increased from 320 ml/min to 2380 ml/min, trichloroethylene (350ppm) conversion decreased slightly but reaction rate increased. When trichloroethylene concentration increased from 100ppm to 6000ppm, reaction rate increased at first —order reaction, indicating a greater reaction potential. The degradation of trichloroethylene was dependent on temperature. The system generated heat itself enough to react at a high temperature (78℃). Degradation of trichloroethylene decreased as the humidity increased. These results are consistent with earlier reports suggesting that UV/TiO2 can decompose trichloroethylene efficiently. It is an inexpensive system easy to operate, and requires no other reagent for the reac
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Lu, Te-Yuan, and 陸德源. "Study of trichloroethylene biodegradation by toluene-utilizing microorganisms." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/33428661628700874768.
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Lee, Yu-Jinn, and 李育俊. "photodissociation of trichloroethylene at 193nm by translational spectroscopy." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/66348272117957762791.
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Huang, Yang-Ting, and 黃仰廷. "Study on Sites with Subsurface Contaminated by Trichloroethylene." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/ak9z6k.
Full textAbstract:
碩士逢甲大學
環境工程與科學學系
106
Field investigation and data analysis were conducted in this study at four sites contaminated by trichloroethylene (TCE) in soil and groundwater. Site A (under-investigation) and Site B (under-remediation) were quickly detected by PID/FID at existing monitoring wells for organic gas concentration. It was found that screening values from Site A is much greater than those from Site B. Soil physical and contamination properties at different depths were collected from at Site C. These data, together with the groundwater data obtained by a consultant firm, reveal that residuals of dense non-aqueous phase liquid (DNAPL) may exist at depths between 3.5-4 m in the unsaturated zone under the plant at Site C. Soil gas monitoring wells were further installed and screened at Site C. They show high organic gas concentration in the unsaturated zone under the plant. This study also used a model, VLEACH, to analysis the leading and vaporization of residual TCE under the plant. Reduction of TCE mass is only 3.7% within a 30 year period due to impermeable cover from the residual TCE in soils. In addition, pressure differential between indoor and outdoor, between subslab and indoor, barometric pressure and temperature were monitored, together with the rainfall records, to assess the exposure durations of vapor intrusion to the building at Site D, since source zone is still under the plant. Preliminary analysis found that the outdoor pressure was mostly higher than the indoor one, so as to reduce exchange rate of the indoor air to the outdoor. During rainfall days, the subslab pressure may be greater than the indoor one, as a result to accelerate the contaminant vapor to intrude into the indoor.
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Hwang, Ru-Yu, and 黃如玉. "Cometabolic Biodegradation of Trichloroethylene by A Toluene-Oxidizing Microorganism." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/31631179295891792772.
Full textAbstract:
碩士國立清華大學
化學工程學系
90
Trichloroethylene (TCE) is readily mineralized under aerobic condition by cometabolism of non-specific oxygenase produced by toluene-oxidizing microorganisms. The objective of this study was to investigate biodegradation of TCE by a toluene-oxidizing microorganism in an aqueous-phase batch reactor, a bubble column bioreactor and a three phase activated carbon biofilter. The aqueous-phase batch experiments were conducted in which the concentration of TCE was held constant (0.98 mg/l, 1.96 mg/l or 3.93 mg/l) whereas the concentration of toluene was varied. The results showed that biodegradation of TCE was observed when the toluene/TCE concentration ratio was greater than 38.6. In contrast to TCE, nearly 100 % removal efficiency of toluene was observed in these experiments. Moreover, with mixtures of TCE, toluene and benzene, both toluene and benzene were biodegraded completely by the toluene-oxidizing microorganism, but TCE was not biodegraded. The removal efficiency of gaseous TCE in the bubble column bioreactor was above 90 % at a retention time of 1.26 min while inlet concentrations of TCE and toluene were 2.06 g/m3 and 2.33 g/m3, respectively. For the three phase activated carbon biofilter, 70 % removal efficiency of gaseous TCE was obtained at the same operating condition. Thus, the bubble column had a better removal efficiency than the three phase carbon biofilter. At the gas flow rate of 150 g/m3-hr and a low TCE concentration of 0.3 g/m3, the bubble column bioreactor could use a lower toluene concentration to sustain the biomass growth and to maximize the TCE biodegradation than the three phase activated carbon biofilter. In addition, at the same gas flow rate and the toluene concentration of 2.1 g/m3, the removal efficiency of the bubble column bioreactor was 90% above for TCE loadings from 5~53 g/m3-hr, while that of the three phase activated carbon biofilter was 80~90% for TCE loadings from 5~64 g/m3-hr. However, the removal efficiency decreased at high concentrations of TCE or toluene, and the decrease in the bubble column was more dramatic than that in the three phase activated carbon biofilter. As a result, at high concentrations of TCE or toluene the three phase activated carbon biofilter, had a higher removal efficiency than the bubble column bioreactor.