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Assessing The Natural Attenuation Of Chlorinated Ethenes In Groundwater Using Compound Specific Stable Isotope Analysis
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Book Synopsis Assessing the Natural Attenuation of Chlorinated Ethenes in Groundwater Using Compound-specific Stable Isotope Analysis by : Christoph Aeppli
Download or read book Assessing the Natural Attenuation of Chlorinated Ethenes in Groundwater Using Compound-specific Stable Isotope Analysis written by Christoph Aeppli and published by . This book was released on 2008 with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Use of Stable Isotopoe Analyses to Assess Natural Attenuation of Chlorinated Ethenes in Groundwater by :
Download or read book Use of Stable Isotopoe Analyses to Assess Natural Attenuation of Chlorinated Ethenes in Groundwater written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Chlorinated ethenes are among the most frequently detected groundwater contaminants in industrially developed countries. Although their degradation pathways have been understood, assessing the progress of natural attenuation of chlorinated ethenes still remains a challenge. This thesis explored the possibilities and limits of the use of compound-specific stable isotope analysis as a field investigation tool to document and to quantify the progress of natural attenuation of chlorinated ethenes. The thesis focused particularly on the fate of reductive dechlorination intermediates such as cis-dichloroethene (cDCE) and vinyl chloride (VC) as the success of natural attenuation of chlorinated ethenes depends principally on the fate of these compounds. Two field investigations were carried out to demonstrate the use of stable isotope analysis to characterize the progress of natural attenuation of chlorinated ethenes. One site was characterized as a complex hydrological and geochemical system at the groundwater-surface water interface where a tetrachloroethene- (PCE) plume discharged through the streambed. Another site was located under relatively stable hydrological conditions and characterized by a 2-km long plume of chlorinated ethenes. Laboratory studies evaluated the use of combined carbon and chlorine isotope analysis to distinguish different degradation pathways of cDCE and VC, and the same approach was employed at a field site to determine the fate of cDCE. Numerical studies evaluated the field applicability of isotope-based quantification, according to the Rayleigh isotope fractionation model, to estimate the extent of degradation and the first-order reaction rate under various flow conditions. In addition, a scheme to quantify the reductive dechlorination rates of chlorinated ethenes based on field concentration and isotope data at one of the field sites was proposed and evaluated with a series of 3D analytical solutions to accommodate sequential reactions. The stu.
Book Synopsis Assessment of Potential for Natural Attenuation of Chlorinated Ethenes and Ethanes in Ground Water at a Petrochemical Reclamation Site, Harris County, Texas by : Glenn F. Huff
Download or read book Assessment of Potential for Natural Attenuation of Chlorinated Ethenes and Ethanes in Ground Water at a Petrochemical Reclamation Site, Harris County, Texas written by Glenn F. Huff and published by . This book was released on 2000 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Application of Stable Isotope Geochemistry to Assess TCE Biodegradation and Natural Attenuation in a Fractured Dolostone Bedrock by : Justin Allen Clark
Download or read book Application of Stable Isotope Geochemistry to Assess TCE Biodegradation and Natural Attenuation in a Fractured Dolostone Bedrock written by Justin Allen Clark and published by . This book was released on 2011 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: Isotopic analyses have been developed over the last 10 years as a method for determining chemical interactions of chlorinated solvents. These methods are especially promising for chlorinated ethenes, such as TCE and DCE. This study further develops and employs TCE and DCE compound specific isotopic analyses, along with chemical analyses, to characterize the degradation of TCE in fractured bedrock aquifers. The site chosen, in Smithville, Ontario, was contaminated by extremely high levels of TCE that is currently undergoing monitored pump-and-treat remediation. A collection of historical data and a extended description of the site are provided for potential use in other research. From December 2008 until April 2010 samples were collected from the site to provide additional data, including isotopic data. The redox conditions at the site are anoxic to reducing, with sulfate reduction and methanogenesis as dominant terminal electron accepting processes. Redox data indicates that electrochemical conditions are highly variable within the site, including areas near the source zone that are less reducing. Documented changes in groundwater conditions to much more reducing environments indicate that increased oxidation of organic matter is occurring at the Smithville site in select wells. Chemical analyses of potential TCE degradation products are employed to identify degradation. Many wells on site have dechlorination products. Combined chemical and redox shows that degradation seems to be a removal process for TCE at the Smithville site. Reductive dechlorination is shown to be a significant process forming degradation products such as DCE, VC, ethene and ethane. Production of DCE in significant amounts, above 1.0 ppb, was observed to only occur after 2003. In addition to this, DCE data shows that the percentage of DCE made up of cDCE is above 96%. This indicates that microbes most likely mediate the processes that formed DCE from TCE. The isotopic data had a high range in both carbon and chlorine isotopes. Chlorine isotopic data ranges from a [delta]37ClTCE of 1.39 to 4.69, and a [delta]37ClcDCE of 3.57 to 13.86. Carbon isotopic data ranges from a [delta]13CTCE of -28.9 to -20.7, and a [delta]13CcDCE of -26.5 to -11.82. Samples collected in the well closest to the source zone returned the lightest carbon and chlorine isotopic signatures. The range in values indicate varying degrees of degradation throughout the site, however the same wells have similar isotopic trends. Based on isotopic evidence, degradation past DCE to more degraded compounds also occurs at the Smithville site. However, determination of the degree of degradation of TCE and DCE was not implemented due to the variability in isotopic data.
Book Synopsis Investigation of Stable Carbon Compound Specific Isotope Analysis to Monitor and Quantify the Biodegradation of Chlorinated Ethenes in Groundwater Systems by : Penny Lea Morrill
Download or read book Investigation of Stable Carbon Compound Specific Isotope Analysis to Monitor and Quantify the Biodegradation of Chlorinated Ethenes in Groundwater Systems written by Penny Lea Morrill and published by . This book was released on 2004 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt: Identification and quantification of chlorinated ethene biodegradation were investigated using carbon compound specific isotope analysis (CSIA). A dynamic headspace sampling technique was developed and shown to be a robust, simple and effective method for isotopic analysis of dissolved chlorinated ethenes at low concentrations ([mu]g/L). This technique was used to monitor the biodegradation of tetrachloroethene (PCE) to ethene at a contaminated field site. At the field site, significant isotopic fractionation characteristic of biodegradation was observed in the isotope values of PCE and its degradation products trichloroethene (TCE), cis -1,2-dichloroethene (cDCE), and vinyl chloride (VC). During this study, stable carbon isotope analysis also provided one of the earliest lines of evidence for biodegradation. In laboratory and field experiments with an emplaced PCE dense nonaqueous phase liquid (DNAPL) source, isotopic fractionation was observed in the isotope values of the dechlorination intermediates produced by biodegradation, but not in the aqueous PCE near the DNAPL. These results confirm the hypothesis that isotopic fractionation due to biodegradation will not be observed in aqueous PCE close to the source zone. A model was developed to predict concentration values from isotope data for each step in the sequential reaction of PCE to non-toxic ethene. ...
Book Synopsis Compound-specific Stable Isotope Analysis by : Maik A Jochmann
Download or read book Compound-specific Stable Isotope Analysis written by Maik A Jochmann and published by Royal Society of Chemistry. This book was released on 2015-11-09 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of Compound-specific Stable Isotope Analysis (CSIA) is increasing in many areas of science and technology for source allocation, authentication, and characterization of transformation reactions. Until now, there have been no textbooks available for students with an analytical chemical background or basic introductory books emphasising the instrumentation and theory. This book is the first to focus solely on stable isotope analysis of individual compounds in sometimes complex mixtures. It acts as both a lecture companion for students and a consultant for advanced scientists in fields including forensic and environmental science. The book starts with a brief history of the field before going on to explain stable isotopes from scratch. The different ways to express isotope abundances are introduced together with isotope effects and isotopic fractionation. A detailed account of the required technical equipment and general procedures for CSIA is provided. This includes sections on derivatization and the use of microextraction techniques in GC-IRMS. The very important topic of referencing and calibration in CSIA is clearly described. This differs from approaches used in quantitative analysis and is often difficult for the newcomer to comprehend. Examples of successful applications of CSIA in food authenticity, forensics, archaeology, doping control, environmental science, and extraterrestrial materials are included. Applications in isotope data treatment and presentation are also discussed and emphasis is placed on the general conclusions that can be drawn from the uses of CSIA. Further instrumental developments in the field are highlighted and selected experiments are introduced that may act as a basis for a short practical course at graduate level.
Book Synopsis Proceedings of the Symposium on Natural Attenuation of Chlorinated Organics in Ground Water by :
Download or read book Proceedings of the Symposium on Natural Attenuation of Chlorinated Organics in Ground Water written by and published by DIANE Publishing. This book was released on 1996 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :Gregory Franklin Slater Publisher :National Library of Canada = Bibliothèque nationale du Canada ISBN 13 :9780612589834 Total Pages :462 pages Book Rating :4.5/5 (898 download)
Book Synopsis Constraining the Fate of Chlorinated Ethenes in Groundwater Systems Using Stable Carbon Compound Specific Isotope Analysis [microform] by : Gregory Franklin Slater
Download or read book Constraining the Fate of Chlorinated Ethenes in Groundwater Systems Using Stable Carbon Compound Specific Isotope Analysis [microform] written by Gregory Franklin Slater and published by National Library of Canada = Bibliothèque nationale du Canada. This book was released on 2001 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Constraining the Fate of Chlorinated Ethenes in Groundwater Systems Using Stable Carbon Compound Specific Isotope Analysis by : Gregory Franklin Slater
Download or read book Constraining the Fate of Chlorinated Ethenes in Groundwater Systems Using Stable Carbon Compound Specific Isotope Analysis written by Gregory Franklin Slater and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The isotopic effects of subsurface processes on the stable carbon isotopic composition, [delta]13C, of chlorinated ethenes were investigated using Compound Specific Isotope Analysis (CSIA). Headspace analysis was determined to be a robust, simple and effective method for sample preparation and analysis using Gas Chromatography-Combustion-Isotope Ratio Mass Spectrometry (GC-C-IRMS). No significant isotopic fractionation (>0.5 ‰) was observed during equilibrium volatilization of the chlorinated ethenes from aqueous solution. Further, no significant isotopic fractionation (>0.5 ‰) was associated with equilibrium sorption of TCE and PCE. These results confirmed the hypothesis that non-degradative, physical subsurface processes would not result in significant isotopic fractionation of the [delta]13C of the chlorinated ethenes. In contrast, degradation of the chlorinated ethenes resulted in large isotopic enrichments of the residual reactant in 13C, consistent with preferential reaction of molecules containing the lighter 12C isotope. This isotopic enrichment could be described by a Rayleigh model enrichment factor ([epsilon]). Rayleigh enrichment factors ([epsilon]) described isotopic fractionation of the chlorinated ethenes during microbial reductive dechlorination of most of the chlorinated ethenes, during abiotic reductive dechlorination of TCE by zero-valent iron, and during aerobic co-metabolic degradation of TCE by toluene ortho-monooxygenase. Enrichment factors varied with specific microbial consortia, with degradation pathway (reductive dechlorination versus aerobic co-metabolism); and for abiotic experiments, with different iron types and surface treatments. The observation of these isotopic enrichment trends indicated that CSIA can provide direct evidence of the occurrence of chlorinated ethene degradation in the field, independent of mass loss due to non-degradative subsurface processes. CSIA was applied at three field sites. These studies confirmed that the [delta] 13CTCE can be conserved at a site where plume geometry is controlled by advective and partitioning processes. Most importantly, they confirmed that CSIA could give direct confirmation of the occurrence of degradation of the chlorinated ethenes at field sites. Therefore CSIA of the [delta] 13C of the chlorinated ethenes represents a powerful tool for the investigation and monitoring of sources and fate of chlorinated ethenes in subsurface systems.
Book Synopsis Investigation of Stable Carbon Compound Specific Isotope Analysis to Monitor and Quantify the Biodegradation Fo Chlorinated Ethenes in Groundwater Systems by : Penny Lea Morrill
Download or read book Investigation of Stable Carbon Compound Specific Isotope Analysis to Monitor and Quantify the Biodegradation Fo Chlorinated Ethenes in Groundwater Systems written by Penny Lea Morrill and published by . This book was released on 2005 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Use of Stable Isotopoe Analyses to Assess Natural Attenuation of Chlorinated Ethenes in Groundwater by : Yumiko Abe
Download or read book Use of Stable Isotopoe Analyses to Assess Natural Attenuation of Chlorinated Ethenes in Groundwater written by Yumiko Abe and published by . This book was released on 2007 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Compound Specific Stable Isotope Analysis by : Safdar Bashir
Download or read book Compound Specific Stable Isotope Analysis written by Safdar Bashir and published by Sudwestdeutscher Verlag Fur Hochschulschriften AG. This book was released on 2014-08-12 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the most promising tools for both characterizing contaminant sources and monitoring in situ degradation of organic contaminants in aquifers is compound-specific stable isotope analysis, in which the stable isotope ratios of one or more elements in a given compound are measured in order to investigate the transformation processes at work.The objective of this book was to validate the application of carbon-compound specific stable isotope analysis (CSIA) and enantiomer specific stable isotope analysis (ESIA) to characterize biotic and abiotic transformation of Hexachlorocyclohexane (HCH) in situ. Additionally, to prove that CSIA in combination with enantiomer-selective degradation of -HCH can be applied as an effective and reliable tool for monitoring natural attenuation of HCH. The variability in enrichment factors observed for enantiomers during biotic investigation showed the preferential reactivity of enzymes for one enantiomer over the other which is not observed in abiotic studies. Thus CSIA combined with ESIA and enantiomer fractions (EF) can help to distinguish biotic and abiotic reactions taking place in situ."
Book Synopsis Constraining the Fate of Chlorinated Ethenes in Groundwater Systems Using Stable Carbon Compound Specific Isotope Analysis by :
Download or read book Constraining the Fate of Chlorinated Ethenes in Groundwater Systems Using Stable Carbon Compound Specific Isotope Analysis written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Compound Specific Isotope Analysis (13C, 37Cl, 2H) to Trace Induced Attenuation of Chlorinated Organic Contaminants in Groundwater by : Carme Audí Miró
Download or read book Compound Specific Isotope Analysis (13C, 37Cl, 2H) to Trace Induced Attenuation of Chlorinated Organic Contaminants in Groundwater written by Carme Audí Miró and published by . This book was released on 2014 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: El chloroform (CF), el tetracloroetè (PCE) i el tricloretè (TCE) són hidrocarburs clor-alifàtics densos usats extensament com a solvents industrials. Aquests compostos s'han alliberat al medi degut a un tractament inadequat dels seus residus. En aquesta tesi, l'efecte d'una barrera permeable reactiva de ferro zero valent (BPR-FZV) instal·lada en un emplaçament contaminat majoritàriament amb PCE, TCE i cis-dicloretè (cis-DCE, subproducte de TCE) ha estat avaluada. A més a més, s'ha proposat i desenvolupat una nova estratègia per a degradar el CF, el qual és un compost recalcitrant, consistent en la inducció de la hidròlisi alcalina del CF mitjançant residus de construcció basats en formigó. L'ànàlisi isotòpic de compost específic (AICE) és una eina valuosa per al monitoreig d'un sistema de tractament medi ambiental, basant-se en el fraccionament isotòpic d'un element durant les reaccions de transformació. L'objectiu general d'aquesta tesi és l'ús de l'anàlisi isotòpic de compost específic de 13C, 37Cl i 2H com una eina per a controlar els dos processos d'atenuació 1) la degradació dels eten-clorats mitjançant una BPR-FZV instal·lada en el camp; i, 2) la nova tècnica de remediació de CF proposada basada en l'ús de residus reciclats de la construcció per tal d'induir la hidròlisi alcalina del CF. En general, mitjançant la combinació dels isòtops de C, Cl i H, aquesta tesi aporta noves eines per discriminar la degradació dels compostos organoclorats d'estudi mitjançant FZV, respecte la biodegradació en el camp, així com també per a identificar fonts de contaminació d'origen industrial o de productes formats, entre d'altres aportacions. A més a més, el nou mètode proposat per a degradar el CF basat en la seva hidròlisi alcalina mitjançant l'ús de residus de construcció reciclats ha demostrat ser eficient en la degradació d'aquest contaminant, així com també, mitjançant l'ús de isòtops de carboni, ha demostrat funcionar en experiments pilot monitorejats a escala de camp.
Book Synopsis Characterizing the Natural Attenuation Potential of Chlorinated Ethenes Contaminated Sites by : Concepcion Carreon-Diazconti
Download or read book Characterizing the Natural Attenuation Potential of Chlorinated Ethenes Contaminated Sites written by Concepcion Carreon-Diazconti and published by . This book was released on 2006 with total page 260 pages. Available in PDF, EPUB and Kindle. Book excerpt: Site characterization methods for measuring the occurrence, magnitude, and rate of microbial mediated transformation processes were evaluated to assess the implementation of monitored natural attenuation (MNA) at chlorinated ethenes contaminated sites. A model site in Arizona, the Park-Euclid WQARF site in Tucson, was selected for the study. Field, geochemical, and compound specific carbon isotope fractionation (CSI) data confirm intrinsic biodegradation is occurring in the perched aquifer. Use of the BIOCHLOR model and a screening protocol support the potential for reductive dehalogenation found in the perched aquifer. Biotransformation of tetrachloroethene to cis-1,2-dichloroethene (cis-DCE) was achieved in microcosm studies. Transformation of cis-DCE to vinyl chloride and to ethene is, at the moment, the laboratory rate limiting step. PCR analysis established that the aquifer contains Dehalococcoides sp. and other dechlorinating microorganisms, though genes that encode for enzymes capable of achieving complete dehalogenation of the chlorinated contaminants were confirmed only in one monitoring well. The regional aquifer shows little evidence of intrinsic biodegradation. This study corroborates that CSI analysis can be used as an additional line of evidence to evaluate and verify MNA. Microbial analysis provides relevant information about the capabilities of native microbial communities to carry out reductive dehalogenation and thus, to naturally attenuate chlorinated compounds at a contaminated site. The combination of microcosm studies, CSI analysis, and bacterial DNA identification is becoming a convincing line of evidence for the assessment of MNA application to chloroethenes contaminated sites.
Book Synopsis Environmental Isotopes in Biodegradation and Bioremediation by : C. Marjorie Aelion
Download or read book Environmental Isotopes in Biodegradation and Bioremediation written by C. Marjorie Aelion and published by CRC Press. This book was released on 2009-11-04 with total page 466 pages. Available in PDF, EPUB and Kindle. Book excerpt: Enhanced analytical capabilities and separation techniques, improved detection limits, and accessibility of instrumentation have led to massive strides in the use of isotopes to assess microbial processes in surface and subsurface sediments. Considering the rapid growth of research and commercial interest in stable isotope and radioisotope applicat
Book Synopsis Natural Attenuation Considerations and Case Studies by : Godage B. Wickramanayake
Download or read book Natural Attenuation Considerations and Case Studies written by Godage B. Wickramanayake and published by . This book was released on 2000 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: - Natural Attenuation Considerations- Natural Attenuation Case Studies I: Chloroethenes- Natural Attenuation Case Studies II: Other Organics and Metals.
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