Download or read book Assessing Mechanisms of Isotopic Fractionation During Petroleum Hydrocarbon Biodegradation written by Silvia Alissa Mancini and published by . This book was released on 2007 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this thesis, mechanisms of carbon and hydrogen isotopic fractionation were investigated during biodegradation of petroleum hydrocarbons, benzene and toluene, in order to evaluate the potential to use Compound Specific Isotope Analysis (CSIA) to assess in situ biodegradation under various field conditions. Variation in carbon and hydrogen enrichment factors, determined using a Rayleigh model, was observed for benzene degradation under different terminal electron accepting processes in enrichment cultures derived from three field sites. This variation was controlled by different biodegradation pathways for the nitrate-reducing cultures, and the methanogenic and sulfate-reducing cultures, as determined by a two-element isotopic approach comparing delta 13C and delta2H values between degradation experiments. Significant differences in carbon and hydrogen enrichment factors were also observed in Pseudomonas putida mt-2 cultures grown under low and high iron concentrations during aerobic toluene biodegradation. These differences were related to changes in the rate-limiting steps of the enzyme-controlled reaction whereby a slower enzyme-catalyzed substrate conversion step (k 2) relative to the enzyme-substrate binding step (k-1) was suggested to occur. No significant differences in carbon and hydrogen isotopic fractionation were observed between a methanogenic enrichment culture and cell free extract experiments during toluene degradation. These results indicated that substrate transport across the cell membrane of the microorganisms involved in biodegradation did not influence isotopic fractionation in this culture.Overall, the results of this thesis demonstrated that resolvable differences in carbon and hydrogen isotopic fractionation were not random but occurred for different microbial communities, biodegradation pathways and growth conditions. Significant 13C and 2H enrichment occurred in all experiments carried out in this thesis, indicating that carbon and hydrogen CSIA has the potential to identify in situ biodegradation of benzene and toluene. In addition, the variability in carbon and hydrogen enrichment factors did not significantly impact the ability to use stable isotope analysis to quantify in situ biodegradation. The measurement of both carbon and hydrogen isotope analysis in laboratory experiments and a field study demonstrated that a two-element isotopic approach is the best approach to differentiate between in situ biodegradation and sources of groundwater contamination, as well as potentially delineate between biodegradation pathways.
Download or read book Isotopic Fractionation During Microbial Decane Degradation written by Melanie Hager and published by . This book was released on 2016-10-01 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Investigating Controls on Variation in Isotopic Fractionation During Biodegradation of Chlorinated Ethenes and Ethanes written by Lisa Marie Douglas and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Kinetic isotope effects occur due to different reaction rates for light and heavy isotope-containing molecules, and are controlled by the bonds broken during degradation. For many primary pollutants, stable carbon, hydrogen, and chlorine isotope effects have been found to fit a Rayleigh model, indicating a single rate-limiting step. This thesis examines biodegradation pathways where additional controls and rate-limiting steps may affect observed isotope fractionation. Two haloalkane dehalogenases catalyzed aerobic 1,2-dichloroethane (1,2-DCA) dechlorination with very different enzyme affinities and turnover rates. However, carbon isotope enrichment factors were the same for both enzymes, reflecting the intrinsic kinetic isotope effect associated with C-Cl bond breakage. Carbon isotope fractionation was also largely constant during anaerobic 1,1,1-trichloroethane (1,1,1-TCA) biodegradation, even when the rate of biodegradation was inhibited by trichloroethene (TCE) co-contamination. This finding provided the basis for carbon isotope-based assessment of 1,1,1-TCE biodegradation at a TCE co-contaminated field site. The wide range of carbon isotope fractionation observed for anaerobic tetrachloroethene (PCE) biodegradation has been a matter of longstanding controversy. This work found the magnitude of carbon isotope fractionation for PCE biodegradation is related to the phylogenetic relationships between PCE-degrading organisms, which may allow for better selection of enrichment factors when assessing PCE biodegradation at field sites. Unexpectedly large variations in carbon isotope fractionation have also been observed for anaerobic TCE biodegradation. During C-Cl bond breakage, slopes of dual element carbon and chlorine isotope effects are typically constant for a given reaction because additional rate-limiting steps affect both elements in a similar way. Hence, characteristic combinations of C/Cl isotope effects can be used to investigate the underlying mechanistic details of a reaction. For TCE biodegradation, C/Cl isotope slopes indicate different reductive dehalogenases may catalyze different reductive dechlorination reaction pathways. This thesis advances the application of compound specific isotope analysis for assessing bioremediation of chlorinated ethenes and ethanes, as well our understanding of the enzymatic degradation mechanisms that catalyze biodegradation.
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 Characterization of the Biochemistry and Physiology of Hydrocarbon Degradation Pathways by Stable Isotope Approaches written by Wei, Xi and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Biodegradation plays an important role in the removal of hydrocarbons from the environment. Compared to the extensive studies concerning aerobic hydrocarbon degradation, there is still a lack of knowledge with regard to the degradation of hydrocarbons under anoxic conditions. The current thesis, containing three subprojects, focused on the anaerobic degradation of the BTEX (abbreviation for benzene, toluene, ethylbenzene, xylene) compound - especially ethylbenzene, n-alkanes and phenols. Phenols are close relatives of BTEX compounds; the biodegradation pathways of phenols and BTEX share many similarities with regard to the activation mechanisms and the enzymes involved. Stable isotope analysis was applied in this thesis as the main tool for the characterization of hydrocarbon degradation pathways and involved microorganisms. The carbon or hydrogen stable isotope fractionation patterns upon biodegradation of TEX, n-alkanes and phenols were determined to elucidate the degradation pathways. Carbon stable isotope labelling method was applied to identify the key-players in an ethylbenzene-degrading enrichment culture. ...
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 Oil in the Sea III written by National Research Council and published by National Academies Press. This book was released on 2003-03-14 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the early 1970s, experts have recognized that petroleum pollutants were being discharged in marine waters worldwide, from oil spills, vessel operations, and land-based sources. Public attention to oil spills has forced improvements. Still, a considerable amount of oil is discharged yearly into sensitive coastal environments. Oil in the Sea provides the best available estimate of oil pollutant discharge into marine waters, including an evaluation of the methods for assessing petroleum load and a discussion about the concerns these loads represent. Featuring close-up looks at the Exxon Valdez spill and other notable events, the book identifies important research questions and makes recommendations for better analysis ofâ€"and more effective measures againstâ€"pollutant discharge. The book discusses: Inputâ€"where the discharges come from, including the role of two-stroke engines used on recreational craft. Behavior or fateâ€"how oil is affected by processes such as evaporation as it moves through the marine environment. Effectsâ€"what we know about the effects of petroleum hydrocarbons on marine organisms and ecosystems. Providing a needed update on a problem of international importance, this book will be of interest to energy policy makers, industry officials and managers, engineers and researchers, and advocates for the marine environment.
Download or read book Using Isotope Fractionation Analysis to Assess Biodegradation of Nitroaromatic Contaminants in the Field written by Reto Simon Wijker and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Filtration Materials for Groundwater written by Ivan Kozyatnyk and published by IWA Publishing. This book was released on 2016-06-15 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ground water is a source for drinking and industrial water supply and pollution created by active industrial sites which often cause social, health, and environmental problems. This groundwater eventually drains into adjacent water sources. Filtration Materials for Groundwater: A Guide to Good Practice presents the up-to-date technology of purification of polluted ground water, its treatment for industrial and human needs and the remediation of polluted sites. The book examines: Types of pollutants in ground water including the main inorganic and organic pollutants and their behaviour. Filtration materials for water treatment and principles of their choice. How to choose suitable filtration materials according to targeted compounds and estimate its efficiency. Technologies for ground water treatment. Cost and risks estimation of treatment facilities. Lifetime, risks and cost estimation of technology. Examples of modern ongoing facilities for ground water treatment and polluted sites remediation. This book is of interest to scientists and engineer who deal with the problem of purification of ground water for different purposes and the remediation of polluted sites.
Download or read book Introduction to Environmental Forensics written by Brian L. Murphy and published by Academic Press. This book was released on 2014-07-30 with total page 747 pages. Available in PDF, EPUB and Kindle. Book excerpt: The third edition of Introduction to Environmental Forensics is a state-of-the-art reference for the practicing environmental forensics consultant, regulator, student, academic, and scientist, with topics including compound-specific isotope analysis (CSIA), advanced multivariate statistical techniques, surrogate approaches for contaminant source identification and age dating, dendroecology, hydrofracking, releases from underground storage tanks and piping, and contaminant-transport modeling for forensic applications. Recognized international forensic scientists were selected to author chapters in their specific areas of expertise and case studies are included to illustrate the application of these methods in actual environmental forensic investigations. This edition provides updates on advances in various techniques and introduces several new topics. - Provides a comprehensive review of all aspects of environmental forensics - Coverage ranges from emerging statistical methods to state-of-the-art analytical techniques, such as gas chromatography-combustion-isotope ratio mass spectrometry and polytopic vector analysis - Numerous examples and case studies are provided to illustrate the application of these forensic techniques in environmental investigations
Download or read book Advances in the Characterisation and Remediation of Sites Contaminated with Petroleum Hydrocarbons written by Jonás García-Rincón and published by Springer Nature. This book was released on 2023-11-22 with total page 677 pages. Available in PDF, EPUB and Kindle. Book excerpt: This open access book synthesizes important advances in the assessment and management of soil and groundwater systems contaminated with petroleum hydrocarbons, especially in the form of light non-aqueous phase liquids (LNAPLs). LNAPL characterization and remediation is challenging due to the multi-phase, multi-component nature of the problem and the various physical, chemical, and biological processes involved in a dynamic and heterogeneous hydrogeological setting. This book focuses on the current state of practice of LNAPL characterization and remediation and seeks to provide information and a framework that would allow some of these complexities to be better addressed by contaminated land practitioners, researchers, and regulators.
Download or read book Xenobiotics in the Soil Environment written by Muhammad Zaffar Hashmi and published by Springer. This book was released on 2017-02-15 with total page 407 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the vast variety of xenobiotics, such as pesticides, antibiotics, antibiotic resistance genes, agrochemicals and other pollutants, their interactions with the soil environment, and the currently available strategies and techniques for soil decontamination and bioremediation. Topics covered include: transport mechanisms of pollutants along the Himalayas; use of earthworms in biomonitoring; metagenomic strategies for assessing contaminated sites; xenobiotics in the food chain; phyto-chemical remediation; biodegradation by fungi; and the use of enzymes and potential microbes in biotransformation. Accordingly, the book offers a valuable guide for scientists in the fields of environmental ecology, soil and food sciences, agriculture, and applied microbiology.
Download or read book Index Medicus written by and published by . This book was released on 2004 with total page 2432 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vols. for 1963- include as pt. 2 of the Jan. issue: Medical subject headings.
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 Geochemistry written by B. Sherwood Lollar and published by Elsevier. This book was released on 2005-05-21 with total page 652 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Treatise on Geochemistry is the first work providing a comprehensive, integrated summary of the present state of geochemistry. It deals with all the major subjects in the field, ranging from the chemistry of the solar system to environmental geochemistry. The Treatise on Geochemistry has drawn on the expertise of outstanding scientists throughout the world, creating the reference work in geochemistry for the next decade. Each volume consists of fifteen to twenty-five chapters written by recognized authorities in their fields, and chosen by the Volume Editors in consultation with the Executive Editors. Particular emphasis has been placed on integrating the subject matter of the individual chapters and volumes. Elsevier also offers the Treatise on Geochemistry in electronic format via the online platform ScienceDirect, the most comprehensive database of academic research on the Internet today, enhanced by a suite of sophisticated linking, searching and retrieval tools.
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
