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Book Isolation and Identification of Polycyclic Aromatic Hydrocarbon Degrading Bacteria from River and Canal Sediments in Bangkok Metropolis

Download or read book Isolation and Identification of Polycyclic Aromatic Hydrocarbon Degrading Bacteria from River and Canal Sediments in Bangkok Metropolis written by Saranya Prapatsornpinyo and published by . This book was released on 2003 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Microbial Community Structure by Fatty Acid Analysis During Polycyclic Aromatic Hydrocarbon Degradation in River Sediment Augmented with Pleurotus Ostreatus

Download or read book Microbial Community Structure by Fatty Acid Analysis During Polycyclic Aromatic Hydrocarbon Degradation in River Sediment Augmented with Pleurotus Ostreatus written by Sarala Kumari Sajja and published by . This book was released on 2008 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research was conducted to determine changes in the microbial community in contaminated sediment during fungal remediation of polycyclic aromatic hydrocarbon (PAH) contaminated Mahoning River sediment. The fungus used for remediation was Pleurotus ostreatus, white rot fungi which is capable of degrading a wide range of organic contaminants including PAHs. Microbial community structure was determined using fatty acid profiles from microbial lipids extracted directly from the sediment. Contaminated sediment was collected from Lowellville, OH and was incubated at 25 °C. There were 4 treatments (1 liter of contaminated river sediment) done in duplicate runs as follows: 1) untreated sediment, 2) sediment amended with sawdust, 3) sediment amended with sawdust and augmented with Pleurotus ostreatus and, 4) sediment amended with sawdust, augmented with Pleurotus ostreatus and amended with extra nitrogen after 21 days. At day 0, 21, and 42, lipids were extracted from each treatment (in triplicate). Microbial fatty acids were purified from the lipid extract, methylated and analyzed by GC-MS. The sediment microbial community structure showed great heterogeneity shown as high variability within triplicate samples and as differences between duplicate treatments. Groups of anaerobic bacteria (sulfate reducers and methanogens) persisted throughout the treatments, even though they were exposed to oxygen during mixing and from the surface during the incubation. The abundance of gram negative bacteria, a group of bacteria associated with PAH degradation, showed highest relative abundance on day 42. Even though the microbial structure changed, the microbial biomass (measured as lipid phosphate) remained consistent between triplicate samples and duplicate runs, and changed little during the incubation.

Book Polycyclic Aromatic Hydrocarbons in Bottom Sediment and Bioavailability in Streams in the New River Gorge National River and Gauley River National Recreation Area West Virginia 2002

Download or read book Polycyclic Aromatic Hydrocarbons in Bottom Sediment and Bioavailability in Streams in the New River Gorge National River and Gauley River National Recreation Area West Virginia 2002 written by Terence Messinger and published by . This book was released on 2004 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Distribution and Dynamics of Pyrene degrading Mycobacteria in Freshwater Sediments Contaminated with Polycyclic Aromatic Hydrocarbons

Download or read book Distribution and Dynamics of Pyrene degrading Mycobacteria in Freshwater Sediments Contaminated with Polycyclic Aromatic Hydrocarbons written by and published by . This book was released on 2008 with total page 231 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microbial biodegradation of polycyclic aromatic hydrocarbons (PAHs) is the primary means of attenuation of these toxic and carcinogenic compounds from contaminated soils and sediments. The documented toxicity and carcinogenicity of many PAHs demands remedial action for PAH-contaminated soils and sediments. This is especially important for historically contaminated sites, where higher molecular weight PAHs (HMW) are recalcitrant. Recently, fast-growing Mycobacteria have been identified that can degrade HMW PAHs, such as pyrene and benzo[a]pyrene. These bacteria have been isolated from a variety of geographical locations, indicating a cosmopolitan distribution. This dissertation work was driven by the need for a better understanding of the ecology, distribution, and dynamics of indigenous microbial populations that can biodegrade PAHs, with an emphasis on Mycobacteria. Both culture-independent molecular approaches and cultivation were used to 1) determine the presence of pyrene-degrading Mycobacterium genotypes and compare dynamics to proteobacterial naphthalene-degradation genotypes; 2) determine the distribution of these genotypes across environments, including different geographical locations (Chattanooga Creek and Lake Erie) and different physical environments (sediments vs. suspended particles); and 3) provide a link between functional pyrene genotypes and phylogenetic identity of isolated pyrene-degrading organisms. The results of these studies indicate the pyrene-degrading Mycobacteria have broad, cosmopolitan distribution in contaminated sediments and suspended particles. Isolation of pyrene-degrading organisms from both Chattanooga Creek and Lake Erie has provided strong evidence for horizontal transfer of pyrenedegrading genes between diverse genera. This work demonstrates the prevalence of pyrene-degrading organisms in contaminated sediments and implicates an integral role in natural attenuation of HMW PAHs.

Book Ecotoxicology Essentials

    Ecotoxicology Essentials

    Book Details:
  • Author : Donald W. Sparling
  • Publisher : Academic Press
  • Release : 2016-04-18
  • ISBN : 0128019611
  • Pages : 502 pages

Download or read book Ecotoxicology Essentials written by Donald W. Sparling and published by Academic Press. This book was released on 2016-04-18 with total page 502 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ecotoxicology Essentials: Environmental Contaminants and Their Biological Effects on Animals and Plants provides a fundamental understanding of this area for students and professionals in ecotoxicology, ecology, conservation, chemistry, public health, wildlife management, fisheries, and many other disciplines. Although new chemicals and potential problems are developed every year, a basic education is essential to address these new challenges, and this work gives such training. Written with the regulatory framework in mind, the material guides readers on modelling, how to conduct assessments, and human and wildlife risk, focusing on effects on animals rather than transport of chemicals. Simple discussions of chemistry are complemented by coverage on the behavior of the animal, dynamics of the ecosystem, real-life situations like drought, and predators in the system – i.e., the natural system versus the lab setting. The book's first section contains chapters on the principles of contaminant toxicology including a brief history of the science of ecotoxicology, basic principles of the science, testing methods, and ways of determining if animals have been exposed to either acute or chronic concentrations of contaminants. The second section deals with the primary classes of contaminants including their chemical characteristics, sources, uses, and effects on organisms. The third section focuses on more complex issues such as the regulation of pollution, population and community effects, risk assessment and modelling. - Uses examples from both aquatic and terrestrial environments and species - Includes a Terms to Know section and a list of study questions in each chapter, fostering a greater understanding of the issues - Focuses on the effects of contaminants on wildlife while providing enough chemistry to allow a detailed understanding of the various contaminant groups - Emphasizes natural examples and 'real' species, rather than laboratory studies on only a handful of organisms - Features case histories, detailing actual events that include aspects of how the contamination occurred and its effects on wildlife - Provides material from a wide variety of international sources

Book Anaerobic Degradation of Polycyclic Aromatic Hydrocarbons at a Creosote contaminated Superfund Site and the Significance of Increased Methane Production in an Organophilic Clay Sediment Cap

Download or read book Anaerobic Degradation of Polycyclic Aromatic Hydrocarbons at a Creosote contaminated Superfund Site and the Significance of Increased Methane Production in an Organophilic Clay Sediment Cap written by Kiara L. Smith and published by . This book was released on 2010 with total page 83 pages. Available in PDF, EPUB and Kindle. Book excerpt: The overall goal of this work was to investigate microbial activity leading to the anaerobic degradation of polycyclic aromatic hydrocarbons and an organophilic clay sediment cap used at a creosote-contaminated Superfund site. To determine whether or not PAHs were being degraded under anaerobic conditions in situ, groundwater and sediment porewater samples were analyzed for metabolic biomarkers, or metabolites, formed in the anaerobic degradation of naphthalene (a low-molecular weight PAH). In addition, a groundwater push-pull method was developed to evaluate whether the transformation of deuterated naphthalene to a deuterated metabolite could be monitored in situ and if conservative rates of transformation can be defined using this method. Metabolites of anaerobic naphthalene degradation were detected in all samples that also contained significant levels of naphthalene. Anaerobic degradation of naphthalene appears to be widespread in the upland contaminated aquifer, as well as within the adjacent river sediments. A zero-order rate of transformation of naphthalene-D to naphthoic acid-D-- was calculated as 31 nM·d-1. This study is the first reported use of deuterated naphthalene to provide both conclusive evidence of the in situ production of breakdown metabolites and an in situ rate of transformation. Methane ebullition was observed in areas of the sediment cap footprint associated with organophilic clay that was used a reactive capping material to sequester mobile non-aqueous phase liquid (NAPL) at the site. Anaerobic slurry incubations were constructed using sediment core samples to quantify the contribution of the native sediment and the different layers of capping material (sand and organophilic clay) to the overall methane production. Substrate addition experiments using fresh, unused organophilic clay, as well as measured changes in total carbon in organophilic clay over time supported the hypothesis that microbes can use organophilic clay as a carbon source. Quantitative PCR (qPCR) directed at the mcrA gene enumerated methanogens in field samples and incubations of native sediment and capping materials. Denaturing gradient gel electrophoresis (DGGE) was also performed on DNA extracted from these samples to identify some of the predominant microorganisms within the sediment cap footprint. The organophilic clay incubations produced up to 1500 times more methane than the native sediment and sand cap incubations. The organophilic clay field sample contained the greatest number of methanogens and the native sediment contained the least. However, the native sediment incubations had greater numbers of methanogens compared to their respective field sample and comparable numbers to the organophilic clay incubation. An increase in methane production was observed with the addition of fresh, unused organophilic clay to the already active organophilic clay incubations indicating that organophilic clay stimulates methanogenesis. In addition, organophilic clay retrieved from the field lost about 10% of its total carbon over a 300-day incubation period suggesting that some component of organophilic clay may be converted to methane. DGGE results revealed that some of the predominant groups within the native sediment and sediment cap were Bacteriodetes, Firmicutes, Chloroflexi, and Deltaproteobacteria. An organism 98% similar to Syntrophus sp. was identified in the organophilic clay suggesting this organism may be working in concert with methanogens to convert the organic component of organophilic clay ultimately to methane. The capacity of organophilic clay to sequester organic contaminants will likely change over time as the organic component is removed from the clay. This, in turn, affects the use of this material as a long-term remedial strategy in reduced, contaminated environments.

Book Polycyclic Aromatic Hydrocarbon Degradaton by Novel Bacteria Isolated from Burrow Sediments of Marine Benthic Macrofauna

Download or read book Polycyclic Aromatic Hydrocarbon Degradaton by Novel Bacteria Isolated from Burrow Sediments of Marine Benthic Macrofauna written by Wai Ki Chung and published by . This book was released on 2001 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book Degradation of Polycyclic Aromatic Hydrocarbons by Actinomycetes

Download or read book Degradation of Polycyclic Aromatic Hydrocarbons by Actinomycetes written by Leticia Pizzul and published by . This book was released on 2006 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt: otic transformation, and probably also the solubilisation, of the high-molecular-weight PAH.

Book Determination of Degradative Gene Frequencies

Download or read book Determination of Degradative Gene Frequencies written by Karen Lynn Mumy and published by . This book was released on 2004 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aerobic polycyclic aromatic hydrocarbon (PAH) degradative pathways have been described in a wide variety of bacteria, fungi and algae. The occurrence and role of these pathways and their corresponding genes in natural attenuation in environmental systems remain poorly understood. The primary goal of this dissertation research was to determine the concentration and frequency of five degradative genes within natural microbial communities exposed to ambient, low and high levels of PAHs using a quantitive-competitive PCR approach adapted for microbial ecology use. PAH concentrations, total microbial biomass and microbial community structure for sediment samples were also determined using a coupled biochemical approach. Community structure analysis indicated that microeukaryotes may be indirectly responding to the contamination, suggesting the development of a PAH-based food web within the microbial communities. Gene frequencies and concentrations reflected increases with elevated levels of contamination. However, the measured frequencies for most genes indicated that only 0.1% or less of the microbial community had the genetic capacity to degrade the contaminants using described aerobic pathways and their corresponding genes and suggested these sequences are rare in these environmental samples. Metabolic assays indicated that the detected genetic capacity was sufficient to account for the overall biodegradative potential observed within the entire sediment microbial community. These data support that, although the reported frequencies were lower than those others have described, the determined frequencies are indicative of the genetic capacity of natural populations in these sediments. While it is likely that additional unidentified degradative pathways and genes exist and are operating in the environment, the data presented in this dissertation support that many of the well understood enzymes and pathways, while primarily studied and defined within laboratory settings, catalyze the majority of the metabolic activity observed in this environmental setting.

Book Bioavailability of Polycyclic Aromatic Hydrocarbons to Bacteria in Estuarine Sediments

Download or read book Bioavailability of Polycyclic Aromatic Hydrocarbons to Bacteria in Estuarine Sediments written by Wenhsin Liang and published by . This book was released on 2002 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt: