Author: Suzanne C. KenneyPublisher:
ISBN:
Category : Coal-tax
Languages : en
Pages : 286
Book Description
Biodegradation of Coal Tar Polycyclic Aromatic Hydrocarbons by Pseudomonas Stutzeri in the Presence of Nonionic Surfactants
Author: Suzanne C. KenneyPublisher:
ISBN:
Category : Coal-tax
Languages : en
Pages : 286
Book Description
Surfactant-enhanced Dissolution and Biodegradation of Polycyclic Aromatic Hydrocarbons in Coal Tar Contaminated Soil
Author: Ick Tae YeomPublisher:
ISBN:
Category : Polycyclic aromatic hydrocarbons
Languages : en
Pages : 386
Book Description
Environmental Degradation and Transformation of Organic Chemicals
Author: Alasdair H. NeilsonPublisher: CRC Press
ISBN: 1420006770
Category : Science
Languages : en
Pages : 738
Book Description
Addressing the persistent environmental threat of organic chemicals with a fresh approach to degradation and transformation processes, Environmental Degradation and Transformation of Organic Chemicals examines a wide range of compounds as well as abiotic and microbiological reactions mediated by microorganisms. The book emphasizes the pathways used
Biodegradation Patterns of Polycyclic Aromatic Hydrocarbons in a Coal Tar-contaminated Soil and Sediment
Author: Hector F. CastroPublisher:
ISBN:
Category : Soil pollution
Languages : en
Pages : 228
Book Description
Environmental Toxicology and Chemistry
Author: Publisher:
ISBN:
Category : Environmental chemistry
Languages : en
Pages : 928
Book Description
Mathematical Modeling and Experimental Verification of Naphthalene Transport and Biodegradation in Soil
Author: Ik-Sung AhnBiodegradation and Relese of Polycyclic Aromatic Hydrocarbons from Natural Organic Matter Surrogates
Author: Christopher Michael HurdzanPublisher:
ISBN:
Category : Benzopyrene
Languages : en
Pages : 94
Book Description
Abstract: A recent study demonstrated that mono-hydroxylated pyrene and benzo[a]pyrene are formed in the human large intestine as a result of metabolism by enteric microorganisms. This is the only documentation of the anaerobic biodegradation of the higher (greater than three rings) polycyclic aromatic hydrocarbons (PAHs). The detection of carboxylated and methylated intermediates formed during the anaerobic mineralization of naphthalene in environmental samples suggest that the anaerobic biodegradation of higher PAHs may produce a variety of terminal or intermediate metabolites in addition to mono-hydroxylates. To investigate this possibility, phenanthrene, pyrene and benzo[a]pyrene were incubated within a suspension of human enteric microorganisms under various treatment conditions. No metabolites were detected. These findings suggest that the biodegradation of PAH is not a major metabolic process of the human large intestine. Recent studies have demonstrated that the aliphatic region of natural organic matter (NOM) can retain appreciable quantities of polycyclic aromatic hydrocarbons (PAHs) due to the presence of non-polar binding sites. Ingested NOM-associated PAH (e.g., benzo[a]pyrene) may be released in the human gastrointestinal tract and converted by liver hepatocytes to various mutagenic or carcinogenic metabolites following absorption. In this study, the release of phenanthrene from the aliphatic NOM surrogates cutin and cutan was measured under simulated human gastrointestinal conditions using three treatments designed to simulate the 1) biological, 2) chemical and 3) biological and chemical conditions of the gastrointestinal environment. Cutin was found to yield an average phenanthrene release 55% higher than cutan (94% vs. 39%). A significant decrease in phenanthrene release was observed in both the additions and additions + fecal treatments as compared to the water treatment (control). The presence of fecal microorganisms did not significantly influence phenanthrene release and did not contribute to a reduced phenanthrene bioaccessibility in gastrointestinal chyme. The results of this study demonstrate that phenanthrene bioaccessibility under simulated human gastrointestinal conditions is significantly influenced by the physical structure of the sorbent matrix as well as the abiotic component of gastrointestinal chyme.
Leachability of Polycyclic Aromatic Hydrocarbons from Coal Tar and Synthesis of the Nanohybrid Photocatalyst for Their Degradation
Author: Publisher:
ISBN:
Category : Electronic dissertations
Languages : en
Pages : 101
Book Description
Photocatalyst -- Leaching -- PAHs -- Photo degradation -- Graphene oxide -- Lixiviant -- Coal tar -- Naphthalene -- Bi2MoO6 -- Demin water -- Synthetic water -- River water
Biodegradation of Polynuclear Aromatic Hydrocarbon Pollutants by Soil and Water Microorganisms
Author: Eva J. McKennaPublisher:
ISBN:
Category : Aromatic compounds
Languages : en
Pages : 44
Book Description
Characterization of Soil Biofilms for the Biodegradation of Polycyclic Aromatic Hydrocarbons
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Polycyclic Aromatic Hydrocarbons (PAHs) are common contaminants in soils and groundwater aquifers, resulting from anthropogenic activities. Major concerns with these compounds are their recalcitrance, toxicity and other unique characteristics in the environment. In situ bioremediation has been successfully used for some PAH degradation in soils, but the optimum conditions for the continuous active growth of microbial communities are not well-understood, so biodegradation processes cannot be properly enhanced. Lab-scale column reactors simulating sandy aquifer environments were used as attachment medium for the biofilm. The biological degradation of a low molecular weight PAH, naphthalene, was investigated, resulting in a 93.5% removal using acetate as a co-substrate. Biofilm mass and extracellular polymeric substances were greatly improved by the presence of acetate, which also promoted the degradation of naphthalene. Biofilm morphology and structure were characterized qualitatively and quantitatively by using confocal microscopy and image analysis, suggesting that porous media biofilms are complex matrixes that develop and change with specific environmental conditions. Sole-substrates, as well as binary/tertiary mixtures of 2-, 3- and 4-ringed PAHs, were examined for competitive/inhibitive interactions on porous media biofilms. While phenanthrene and pyrene could not be degraded as sole carbon sources, binary systems of the 3- and 4-ring PAHs with acetate and naphthalene supplements stimulated their degradation, with up to 87.9% and 70.1% removal efficiencies, respectively. However, inhibition of pyrene degradation by phenanthrene was observed in the tertiary systems. Heterogeneous surface films and a variety of biological aggregate structures and growth patterns were observed by confocal microscopy. A nonionic surfactant was tested for water solubility enhancements of naphthalene, phenanthrene and pyrene. Solutions of Triton X-100 above the critical micelle concentration (CMC) showed great solubilization of the three PAHs. Batch experiments were also conducted to investigate the sorption effects of PAHs and/or Triton X-100 to the porous media, as well as the partitioning to live/killed biofims. Low amounts of surfactant were found to be adsorbed onto sand and biofilm; Triton X-100 appeared to increase PAH sorption, but sorbed concentrations were still considered negligible. The effects of the nonionic surfactant on the biodegradation of PAHs were also investigated. Column experiments showed that the degradation of the 2-ring PAH alone was not affected and only a small enhancement of 3- and 4-ring PAH (as sole-substrates) degradation occurred by Triton X-100 addition. Higher biodegradations were always achieved by having just PAH mixtures without the surfactant, indicating the importance of cross feeding / cometabolic mechanisms over improved solubilization of PAHs.