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 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 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 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 Biodegradation of Nitroaromatic Compounds and Explosives written by Jim C. Spain and published by CRC Press. This book was released on 2000-06-14 with total page 451 pages. Available in PDF, EPUB and Kindle. Book excerpt: Filled with practical applications and research, Biodegradation of Nitroaromatic Compounds and Explosives presents an international perspective on environmental contamination from explosives. It covers biodegradation strategies for DNT and a wide variety of other nitroaromatic compounds of environmental significance and makes the information access

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 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 Environmental Organic Chemistry written by Rene P. Schwarzenbach and published by John Wiley & Sons. This book was released on 2016-11-07 with total page 1026 pages. Available in PDF, EPUB and Kindle. Book excerpt: Examines in a pedagogical way all pertinent molecular and macroscopic processes that govern the distribution and fate of organic chemicals in the environment and provides simple modeling tools to quantitatively describe these processes and their interplay in a given environmental system Treats fundamental aspects of chemistry, physics, and mathematical modeling as applied to environmentally relevant problems, and gives a state of the art account of the field Teaches the reader how to relate the structure of a given chemical to its physical chemical properties and intrinsic reactivities Provides a holistic and teachable treatment of phase partitioning and transformation processes, as well as a more focused and tailor-made presentation of physical, mathematical, and modeling aspects that apply to environmental situations of concern Includes a large number of questions and problems allowing teachers to explore the depth of understanding of their students or allowing individuals who use the book for self-study to check their progress Provides a companion website, which includes solutions for all problems as well as a large compilation of physical constants and compound properties

Download or read book Verification of Biodegradation Delineation of Biodegradation Mechanisms and Differentiation of Sources of Chlorinated Contaminants Using Compound Specific Isotope Analysis written by Michelle Marie Grace Chartrand and published by . This book was released on 2007 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal of this thesis was to investigate the use of compound specific isotope analysis (CSIA) in contaminant hydrogeology by addressing four specific goals. First, carbon isotope (delta13C) measurements of trichlorethene (TCE), and its degradation products cis-1,2-dichloroethene (cDCE) and vinyl chloride (VC) from samples collected from a fractured bedrock field site were able to conclusively demonstrate that biodegradation was occurring, despite fluctuating concentration profiles of these compounds due to ongoing TCE dissolution and variable hydraulic gradients.Next, delta13C values were measured for aerobic cDCE and VC biodegradation. For the aerobic VC degrading microorganisms Mycobacterium sp. strains JS60, JS61 and JS614, and Nocardioides sp. strain 614, the first step in the biodegradation pathway involved a monooxygenase enzyme, which oxidized VC to chlorooxirane, and the measured enrichment factors ranged between -8.2 +/- 0.1 to --7.0 +/- 0.3 ‰. Larger fractionation was measured during aerobic cDCE biodegradation by Polaromonas sp. strain JS666 (-17.4 +/- 2.4 to --22.4 +/- 0.8 ‰). KIEs calculated from the measured enrichment factors suggests that the initial degradation step in the aerobic cDCE biodegradation pathway is not consistent with an initial attack on the carbon double bond by a monooxygenase enzyme to form an epoxide, as was observed for VC aerobic biodegradation.Third, a method was developed to measure the hydrogen isotope (delta 2H) values for chlorinated compounds. After 71 1,2-dichloroethane (1,2-DCA) delta2H measurements were obtained, the reproducibility of the modified system had degraded outside of acceptable analytical uncertainty. Combined delta2H and delta13C values of 1,2-DCA demonstrated that dual parameter isotopic measurements can distinguish between different contaminant sources, and may provide additional constraints on degradation pathways and contaminant remediation.Finally, a CSIA method was developed to analyze hexachlorocyclohexane (HCH) isomers. A range of delta13C values were obtained for alpha- and gamma-HCH from both pure product standards and technical grade HCH mixtures, demonstrating that CSIA has the potential to distinguish between different HCH sources. Further, delta13C analysis of HCH isomers at a contaminated field site may provide two additional lines of evidence that biodegradation of HCH isomers was occurring.

Download or read book Stable Isotopic and Molecular Biological Tools to Validate Biodegradation of 1 4 dioxane written by Peerapong Pornwongthong and published by . This book was released on 2014 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt: 1,4-Dioxane, a probable human carcinogen, is a heterocyclic ether increasingly found as a contaminant in water supplies. Recent studies have reported that 1,4-dioxane can be biodegraded by a variety of microorganisms, and bioremediation may be an effective strategy for 1,4-dioxane contaminated sites. However, reliable monitoring tools to validate biodegradation of 1,4-dioxane are still lacking. Molecular biological tools and stable isotope-based tools have been previously applied as diagnostic tools for monitored natural attenuation and engineered bioremediation of various organic and inorganic compounds. In this study, molecular biological tools were used for determining bacterial populations, and for associating 1,4-dioxane biodegradation with relative copy numbers of phylogenetic and functional genes. These biomarkers were amplified using primers designed from the genome sequence data of 1,4-dioxane-degrading bacterium Pseudonocardia dioxanivorans CB1190, and were correlated with measured biodegradation rates. The results revealed that abundance of DXMO and 16S rRNA were in agreement with 1,4-dioxane biodegradation rates, and could be used to illustrate the inhibitory effect of co-contaminant transition metals Cu(II), Cd(II), Ni(II), and organic ligands such as tannic acid and L-cysteine. It should be recognized that biomarkers provide an indirect association between genes and enzyme activity. Factors regulating protein synthesis and catalytic activities of enzymes are not captured by nucleic acid-based biomarkers. This complicates the interpretation of biomarkers for predicting biodegradation rates. Compound specific isotope analysis (CSIA) could be used as another diagnostic tool to assess 1,4-dioxane biodegradation. In this study, hydrogen and carbon isotope analyses of 1,4-dioxane were successfully developed to determine isotope signatures of commercial 1,4-dioxane, and applied to determine kinetic isotope fractionation associated with biodegradation in both pure and mixed cultures, as well as abiotic degradation of 1,4-dioxane. During biodegradation, both 2H and 13C were enriched, while abiotic processes could enrich only 2H in residual 1,4-dioxane. This indicated that combined carbon and hydrogen isotope analyses of 1,4-dioxane allow differentiation of biological processes from abiotic mechanisms. Availability of stable isotopic and molecular biological tools will allow environmental engineering professionals to include bioremediation as an effective strategy in the cleanup of specific environmental contaminants.

Download or read book Biological Remediation of Explosive Residues written by Shree Nath Singh and published by Springer Science & Business Media. This book was released on 2013-08-04 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microbial degradation, Phytoremediation, Remediation, Explosive residues, Biotransformation, Mineralization, Degradative Enzymes, Degradation Pathways, Energetics, Soil contamination, Water contamination.

Download or read book Water Security Big Data Driven Risk Identification Assessment and Control of Emerging Contaminants written by Bin Liang and published by Elsevier. This book was released on 2024-06-12 with total page 671 pages. Available in PDF, EPUB and Kindle. Book excerpt: Water Security: Big Data-Driven Risk Identification, Assessment and Control of Emerging Contaminants contains the latest information on big data-driven risk detection and analysis, risk assessment and environmental health effect, intelligent risk control technologies, and global control strategy of emerging contaminants. First, this book highlights advances and challenges throughout the detection of emerging chemical contaminants (e.g., antimicrobials, microplastics) by sensors or mass spectrometry, as well as emerging biological contaminant (e.g., ARGs, pathogens) by a combination of next- and third-generation sequencing technologies in aquatic environment. Second, it discusses in depth the ecological risk assessment and environmental health effects of emerging contaminants. Lastly, it presents the most up-to-date intelligent risk management technologies. This book shares instrumental global strategy and policy analysis on how to control emerging contaminants. Offering interdisciplinary and global perspectives from experts in environmental sciences and engineering, environmental microbiology and microbiome, environmental informatics and bioinformatics, intelligent systems, and knowledge engineering, this book provides an accessible and flexible resource for researchers and upper level students working in these fields. - Covers the detection, high-throughput analyses, and environmental behavior of the typical emerging chemical and biological contaminants - Focuses on chemical and biological big data driven aquatic ecological risk assessment models and techniques - Highlights the intelligent management and control technologies and policies for emerging contaminants in water environments

Download or read book Bioavailability of Contaminants in Soils and Sediments written by National Research Council and published by National Academies Press. This book was released on 2003-05-03 with total page 433 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bioavailability refers to the extent to which humans and ecological receptors are exposed to contaminants in soil or sediment. The concept of bioavailability has recently piqued the interest of the hazardous waste industry as an important consideration in deciding how much waste to clean up. The rationale is that if contaminants in soil and sediment are not bioavailable, then more contaminant mass can be left in place without creating additional risk. A new NRC report notes that the potential for the consideration of bioavailability to influence decision-making is greatest where certain chemical, environmental, and regulatory factors align. The current use of bioavailability in risk assessment and hazardous waste cleanup regulations is demystified, and acceptable tools and models for bioavailability assessment are discussed and ranked according to seven criteria. Finally, the intimate link between bioavailability and bioremediation is explored. The report concludes with suggestions for moving bioavailability forward in the regulatory arena for both soil and sediment cleanup.

Download or read book Ecological Biochemistry written by Gerd-Joachim Krauss and published by John Wiley & Sons. This book was released on 2014-08-29 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first stand-alone textbook for at least ten years on this increasingly hot topic in times of global climate change and sustainability in ecosystems. Ecological biochemistry refers to the interaction of organisms with their abiotic environment and other organisms by chemical means. Biotic and abiotic factors determine the biochemical flexibility of organisms, which otherwise easily adapt to environmental changes by altering their metabolism. Sessile plants, in particular, have evolved intricate biochemical response mechanisms to fit into a changing environment. This book covers the chemistry behind these interactions, bottom up from the atomic to the system's level. An introductory part explains the physico-chemical basis and biochemical roots of living cells, leading to secondary metabolites as crucial bridges between organisms and the respective ecosystem. The focus then shifts to the biochemical interactions of plants, fungi and bacteria within terrestrial and aquatic ecosystems with the aim of linking biochemical insights to ecological research, also in human-influenced habitats. A section is devoted to methodology, which allows network-based analyses of molecular processes underlying systems phenomena. A companion website offering an extended version of the introductory chapter on Basic Biochemical Roots is available at http://www.wiley.com/go/Krauss/Nies/EcologicalBiochemistry

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 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 Contaminants in the Subsurface written by National Research Council and published by National Academies Press. This book was released on 2005-04-23 with total page 371 pages. Available in PDF, EPUB and Kindle. Book excerpt: At hundreds of thousands of commercial, industrial, and military sites across the country, subsurface materials including groundwater are contaminated with chemical waste. The last decade has seen growing interest in using aggressive source remediation technologies to remove contaminants from the subsurface, but there is limited understanding of (1) the effectiveness of these technologies and (2) the overall effect of mass removal on groundwater quality. This report reviews the suite of technologies available for source remediation and their ability to reach a variety of cleanup goals, from meeting regulatory standards for groundwater to reducing costs. The report proposes elements of a protocol for accomplishing source remediation that should enable project managers to decide whether and how to pursue source remediation at their sites.