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.
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.
Download or read book Compound specific Isotope Analysis written by and published by . This book was released on 1999 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Compound specific Isotope Analysis to Delineate the Sources and Fate of Organic Contaminants in Complex Aquifer Systems written by Michaela Blessing and published by . This book was released on 2008 with total page 127 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
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."
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:
Download or read book Application of Two Dimensional Compound Specific Carbon chlorine Isotope Analyses for Degradation Monitoring and Assessment of Organic Pollutants in Contaminated Soil and Groundwater written by and published by . This book was released on 2013 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Isotopic Applications to Contaminant Hydrogeology written by Helen Stephanie Dempster and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Compound Specific Isotope Ratio Analysis in Vapour Intrusion Studies Using Waterloo Membrane Sampler WMS written by Oana Goli and published by . This book was released on 2013 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt: Compound specific isotope analysis (CSIA) has been used extensively for fingerprinting applications and for the evaluation of the degradation processes in organic contaminant studies in groundwater. Recently, an increase in academic interest on the potential applications of CSIA in vapour intrusion has been observed, and various studies have been conducted. A key challenge of this research is the development of analytical protocols for CSIA that handle very low concentrations of organic compounds typically found in indoor samples. A sampling device capable of gathering enough mass for CSIA has to be tested for field applications. In this research the Waterloo Membrane Sampler (WMS), a permeation-type passive sampler that has been successfully used in numerous studies, is presented as a potential device for this purpose. Indeed, the WMS has been successfully applied in the quantitation of volatile analytes in indoor and outdoor air, as well as soil-gas matrices. The objective of this research was to evaluate the applicability of the WMS for CSIA in vapour intrusion studies. Analyte amounts sufficient for CSIA were collected when using thermal desorption to introduce the sample into the gas chromatography-isotope ratio mass spectrometry system (TD-GC-IRMS). The TD-GC-IRMS was employed to determine the stable carbon isotopic composition ([delta]13C) of three model analytes: hexane, benzene and trichloroethylene, which were contained in a standard gas mixture. In order to determine whether isotopic fractionation occurred during the exposure, measures of [delta]13C were taken for individual compounds found in both the standard gas (active sampling) and in the gas permeating through the PDMS membrane into the sorbent (passive sampling). Various WMS were exposed to the standard gas for 3, 6, 12, 24, 48, 96 and 192 hours. Variations of the isotopic carbon composition for each analyte were measured versus time, amount of analytes sorbed and exposure temperature. Results obtained in all studies indicate good reproducibility with a standard deviation within the accepted analytical error of ± 0.5 [per mille]. All sampling processes introduced small isotopic fractionation; however, the degree of fractionation remained practically constant and independent of sampling time, mass adsorbed and temperature, therefore could be accounted for. The new method developed was applied in a field study, where the results obtained were compared with solvent base active sample collection and analysis. Results obtained demonstrated good data reproducibility. This indicates that CSIA coupled with WMS could be a valuable tool in environmental forensics field.
Download or read book Guidelines for Sediment Tracing Using the Compound Specific Carbon Stable Isotope Technique written by International Atomic Energy Agency and published by . This book was released on 2019 with total page 57 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Method for Isotopic Analysis of Chlorinated Organic Compounds written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The present invention provides a method for preparing a VOC sample for carbon and chlorine isotope ratio analysis by mass spectrometer. A VOC sample is placed in a combustion tube and reacted with CuO to form CO.sub. 2 and CuCl. The CO.sub. 2 is then extracted and analyzed for the carbon isotope ratio. The CuCl is separated from the excess CuO and reacted with CH.sub. 3 I to form CH.sub. 3 Cl, extracted and analyzed for chlorine isotope ratio.
Download or read book Application of Compound Specific Stable Isotope Analysis to Spatial and Temporal Tracing of Organic Molecular Biomarkers Through the Environment written by Abigail M Oakes and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the critical challenges facing modern environmental chemistry is how to identify sources, process of formation, and transport of organic compounds and pollutants in the environment. In recent decades, molecular and stable isotopic analysis of individual organic biomarkers, produced by living organisms, has emerged as a novel tool for identifying sources and processes associated with the synthesis of biological compounds. Specifically, this thesis focused on the questions related to processes controlling the production and movement of n-alkanes produced in plant leaf waxes and PAHs produced through the partial combustion of organic material. The aims of this thesis were to use compound-specific isotope analysis of these organic molecular biomarkers to understand how environmental changes are recorded, determine source materials, and evaluate potential methods of transport through the environment. Chapters 3 and 4 used stable hydrogen (Î ́D) and carbon (Î ́13C) isotopes of n-alkanes produced by leaf waxes to determine how differences in taxonomic class are recorded and how these biomarkers are preserved in fluvial sediments. This study found that n-alkanes from individual plants record plant specific differences in photosynthetic processes and physiology whereas n‑alkanes preserved in fluvial sediments can identify large scale ecosystem changes. In Chapter 5, the concentrations, Î ́D and Î ́13C of 16 EPA priority PAHs were measured from samples collected from around the states of Connecticut and Rhode Island. Using a multivariate approach to source identification, this study found that PAHs extracted from sediments and soils in Connecticut were sourced from a complex mixture of vehicular exhaust, coal burning exhaust, and industrial emissions. These projects represent a significant contribution to the understanding of carbon mobility over the earth surface with broad applications to environmental pollution tracing and paleoenvironmental reconstructions.
Download or read book Stable Isotopic Investigations of In situ Bioremediation of Chlorinated Organic Solvents written by and published by . This book was released on 1999 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this project was to investigate the potential applications of stable isotope ratio measurements in characterization of the source terms, the transport, and the fate of chlorinated solvents in groundwater aquifers. The approach to this research was threefold: to develop methods for the sampling and isotopic analysis of chlorinated solvents in groundwaters; to perform laboratory experiments to measure equilibrium and kinetic isotope effects associated with biological and physical transformation processes of chlorinated solvents; and to perform field investigations at well-characterized, contaminated aquifer sites to demonstrate the applicability of the isotopic approach in real-world situations. New methods were developed for the extraction and isotopic analysis of chlorinated solvents in water samples. The new methods were applied to a series of laboratory experiments assessing the isotope effects associated with biological and physical transformation processes. The authors found that a large kinetic isotope effect was caused by microbial degradation of chlorinated solvents, under both aerobic and anaerobic conditions. The evaporation of chlorinated solvents also caused a large isotope effect, but in that case the carbon isotopic fractionation was in the reverse sense. Isotopic fractionation associated with adsorption and chemical exchange of chlorinated solvents was negligible. The authors performed field investigations at five present and former industrial sites undergoing various stages of remediation. These investigations were collaborative with Lockeed-Martin Energy Systems, Inc., and ENSR, Inc., the companies responsible for the remedial work at these sites. Application of the new sampling and analytical methods at these sites showed that stable isotopic measurements yield powerful insights into underground processes. In particular, they found positive evidence for in-situ microbial degradation of chlorinated solvents at all five sites, evidence for volatilization of chlorinated solvents at three sites, and evidence for multiple sources of chlorinated solvents at two sites. At a site where six-phase heating was applied, they found evidence for increased solubilization of pure phase chlorinated solvents during heating. The general conclusion of the field investigations is that stable isotope measurements should become an essential component in site characterization and remediation of sites contaminated with chlorinated solvents.
Download or read book The Geochemistry of Stable Chlorine and Bromine Isotopes written by Hans Eggenkamp and published by Springer. This book was released on 2014-08-25 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides detailed information on the history, analysis and applications of chlorine and bromine isotope geochemistry. Chlorine and bromine are geochemically unique as they prefer to exist as single charged negative ions. For this reason isotope fractionation reflects mostly processes that are not related to changes in the redox state and this fractionation is generally modest. The book will describe the processes that are most easily detected using these isotopes. Also isotope variations, and processes that cause them, measured in oxidised species such as perchlorates and in organic molecules will be described in this book.
Download or read book Compound Specific Isotope Analysis written by Eva Katharina Richter and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Transverse Dispersion in Liquid Flow Through Porous Media written by Eugene Sidney Simpson and published by . This book was released on 1962 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:
