Download or read book Investigating Mechanisms of Chlorinated Ethane Biotransformation Using Compound Specific Carbon Isotope Analysis written by Sarah Kathleen Hirschorn and published by . This book was released on 2007 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stable carbon isotope fractionation during biotransformation of the chlorinated ethanes 1,2-dichloroethane (1,2-DCA), 1,1,1-trichloroethane (1,1,1-TCA) and 1,1-dichloroethane (1,1-DCA) was investigated. Isotopic fractionation during aerobic 1,2-DCA biotransformation in microcosms, enrichment cultures and pure microbial cultures was measured and was found to be pathway dependent. Biodegradation of 1,2-DCA under aerobic conditions produced a consistent bimodal distribution of enrichment factors (s) with one mean c centered on --3.9 +/- 0.6 and the other on --29.2 +/- 1.9. Reevaluation of epsilon in terms of kinetic isotope effects 12k/ 13k, gave values of 12k/13k = 1.01 and 1.06, which are typical of oxidation and hydrolytic dehalogenation (S N2) reactions, respectively. The relationship between degradation pathway and measured carbon isotope fractionation was applied to constrain the degradation pathway of 1,2-DCA in a microbial enrichment culture capable of degrading 1,2-DCA under both O2 and NO3-reducing conditions, but where the degradation pathway was previously uncharacterized. delta 13C values indicated biodegradation in the enrichment culture under both O2 and NO3-reducing conditions likely proceeded via a hydrolytic dehalogenase enzyme. Stable carbon isotope analysis during biotransformation of other chlorinated ethanes was then investigated. Isotopic enrichment factors of -1.9 and -10.4 were measured during reductive dechlorination of 1,1,1-trichloroethane (1,1,1-TCA) and 1,1-dichloroethane (1,1-DCA), respectively. These are the first reported isotopic enrichment factors for microbial biotransformation of these compounds, which can now potentially be applied to investigate and quantify biodegradation of 1,1,1-TCA and 1,1-DCA in the field. Stable carbon isotope analysis was used to provide a conservative estimate of the extent of 1,2-DCA and trichloroethene (TCE) biodegradation in a biostimulation field study. Isotope analysis was able to confirm that 1,2-DCA degradation, rather than degradation of vinyl chloride, was the primary mechanism of ethene production at the site. This thesis not only advances the application of compound specific carbon isotope fractionation to identify and quantify biodegradation of chlorinated ethanes in groundwater, but in particular progresses our understanding of the relationship between the enzymatic mechanisms of contaminant degradation and isotopic fractionation, and the ability to use that knowledge to predict degradation mechanisms for previously unconstrained pathways of contaminant remediation.
Download or read book Dissertation Abstracts International written by and published by . This book was released on 2008 with total page 800 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 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 How Tobacco Smoke Causes Disease written by United States. Public Health Service. Office of the Surgeon General and published by . This book was released on 2010 with total page 728 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report considers the biological and behavioral mechanisms that may underlie the pathogenicity of tobacco smoke. Many Surgeon General's reports have considered research findings on mechanisms in assessing the biological plausibility of associations observed in epidemiologic studies. Mechanisms of disease are important because they may provide plausibility, which is one of the guideline criteria for assessing evidence on causation. This report specifically reviews the evidence on the potential mechanisms by which smoking causes diseases and considers whether a mechanism is likely to be operative in the production of human disease by tobacco smoke. This evidence is relevant to understanding how smoking causes disease, to identifying those who may be particularly susceptible, and to assessing the potential risks of tobacco products.
Download or read book Environmental Soil Remediation and Rehabilitation written by Eric D. van Hullebusch and published by Springer Nature. This book was released on 2020-04-22 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive overview of innovative remediation techniques and strategies for soils contaminated by heavy metals or organic compounds (e.g. petroleum hydrocarbons, NAPLs and chlorinated organic compounds). It discusses various novel chemical remediation approaches (in-situ and ex-situ) used alone and in combination with physical and/or thermal treatment. Further, it addresses the recovery of NAPLs, reuse of leaching solutions, and in-situ chemical reduction and oxidation, and explores the chemical enhancement of physical NAPLs recovery from both practical and theoretical perspectives. Also presenting the state-of-the-art in waste-assisted bioremediation to improve soil quality and the remediation of petroleum hydrocarbons, the book is a valuable resource for students, researchers and R&D professionals in industry engaged in the treatment of contaminated soils.
Download or read book Organic Contaminants in Riverine and Groundwater Systems written by Jan Schwarzbauer and published by Springer Science & Business Media. This book was released on 2006-04-04 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reviews a selection of organic-geochemical investigations, dealing with the characterization and environmental behaviour of organic contaminations of German river and groundwater systems. Topics include comprehensive non-target screening as well as isotope analysis of contaminants in water and sediments, detailed characterisation of bound residues, recording riverine pollution histories and an extensive application of the anthropogenic marker approach.
Download or read book Organic Chemicals in the Environment written by Alasdair H. Neilson and published by CRC Press. This book was released on 2012-09-05 with total page 1047 pages. Available in PDF, EPUB and Kindle. Book excerpt: Addressing the persistent environmental threat of organic chemicals with a fresh approach to degradation and transformation processes, Organic Chemicals in the Environment: Mechanisms of Degradation and Transformation, Second Edition examines a wide range of compounds as well as abiotic and microbiological reactions mediated by microorganisms
Download or read book Toxicological Profile for 1 2 dibromoethane written by and published by . This book was released on 1992 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Toxicological Profile for Tetrachloroethylene written by and published by . This book was released on 1997 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Environmental Tracers in Subsurface Hydrology written by Peter G. Cook and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 545 pages. Available in PDF, EPUB and Kindle. Book excerpt: Environmental Tracers in Subsurface Hydrology synthesizes the research of specialists into a comprehensive review of the application of environmental tracers to the study of soil water and groundwater flow. The book includes chapters which cover ionic tracers, noble gases, chlorofluorocarbons, tritium, chlorine-36, oxygen-18, deuterium, and isotopes of carbon, strontium, sulphur and nitrogen. Applications of the tracers include the estimation of vertical and horizontal groundwater velocities, groundwater recharge rates, inter-aquifer leakage and mixing processes, chemical processes and palaeohydrology. Practicing hydrologists, soil physicists and hydrology professors and students will find the book to be a valuable support in their work.
Download or read book Comprehensive Environmental Mass Spectrometry written by Albert Lebedev and published by ILM Publications. This book was released on 2012 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt: "In full colour throughout, this book describes the power of mass spectrometry in resolving environmental issues, demonstrating how real-world complex problems can be solved in a simple and elegant way."--Worldcat.
Download or read book Novel Approaches for Bioremediation of Organic Pollution written by Raffi Fass and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 353 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the 42nd OHOLO Conference held in Eilat, Israel, May 3-7, 1998
Download or read book Environmental Tracers written by Trevor Elliot and published by MDPI. This book was released on 2018-10-08 with total page 1 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue "Environmental Tracers" that was published in Water
Download or read book In Situ Bioremediation written by National Research Council and published by National Academies Press. This book was released on 1993-02-01 with total page 225 pages. Available in PDF, EPUB and Kindle. Book excerpt: In situ bioremediationâ€"the use of microorganisms for on-site removal of contaminantsâ€"is potentially cheaper, faster, and safer than conventional cleanup methods. But in situ bioremediation is also clouded in uncertainty, controversy, and mistrust. This volume from the National Research Council provides direction for decisionmakers and offers detailed and readable explanations of: the processes involved in in situ bioremediation, circumstances in which it is best used, and methods of measurement, field testing, and modeling to evaluate the results of bioremediation projects. Bioremediation experts representing academic research, field practice, regulation, and industry provide accessible information and case examples; they explore how in situ bioremediation works, how it has developed since its first commercial use in 1972, and what research and education efforts are recommended for the future. The volume includes a series of perspective papers. The book will be immediately useful to policymakers, regulators, bioremediation practitioners and purchasers, environmental groups, concerned citizens, faculty, and students.
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
Download or read book Toxicological Profile for Toxaphene written by and published by . This book was released on 1996 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt:
