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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.
This timely reference presents the state of the art of the emerging and rapidly changing field of bioremediation of chlorinated solvents, PCBs, and other chlorinated compounds, as well as PAHs, both in situ and on site. This landmark publication reports significant advances in bioremediation, with an emphasis on practical applications and state-of-the-art developments. Laboratory and field-oriented reviews are presented with the objective of tying treatability studies and recent laboratory developments to field applications. No other reference source gives you access to the most current techniques and methods for the bioremediation of chlorinated and polycyclic aromatic hydrocarbon compounds. This book represents the work of leading experts in the fields of in situ and on-site bioremediation from North America, Europe, and Asia. The chapters include current field applications and laboratory studies undertaken, in some cases, in countries with regulatory standards more stringent than those of the United States.
The introduction of synthetic organic chemicals into the environment during the last few decades has given rise to major concern about the ecotoxicological effects and ultimate fate of these compounds. The pollutants that are considered to be most hazardous because of their intrinsic toxicity, high exposure level, or recalcitrant behavior in the environment have been placed on blacklists and other policy priority lists. The fate of synthetic compounds that enter the environment is mainly determined by their rate of biodegradation, which therefore also has a major effect on the degree of bioaccumulation and the risk of ecotoxicological effects. The degree and rate of biodegradation is also of critical importance for the feasibility of biological techniques to clean up contaminated sites and waste streams. The biodegradation of xenobiotics has thus been the subject of numerous studies, which resulted in thousands of publications in scientific journals, books, and conference proceedings. These studies led to a deeper understanding of the diversity of biodegradation processes. As a result, it has become possible to enhance the rate of degradation of recalcitrant pollutants during biological treatment and to design completely new treatment processes. At present, much work is being done to expand the range of pollutants to which biodegradation can be applied, and to make treatment techniques less expensive and better applicable for waste streams which are difficult to handle.
This volume concerns sources of polycyclic aromatic hydrocarbons (PAH), their emission factors, and relative importance. It deals with exposure, uptake, metabolism, and detection of PAH in the human body. The volume contains an update of information in environmental and biochemical studies of PAH.
Our interest in Mulhouse for carbon black and soot began some 30 years ago when J.B. Donnet developed the concept of surface chemistry of carbon and its involvement in interactions with gas, liquid and solid phases. In the late sixties, we began to study soot formation in pyrolytic systems and later on in flames. The idea of organ1z1ng a meeting on soot formation originated some four or five years ago, through discussions among Professor J.B. Howard, Dr. A. D'Alessio and ourselves. At that time the scientific community was becoming aware of the necessity to strictly control soot formation and emission. Being involved in the study of surface properties of carbon black as well as of formation of soot, we realized that the combustion community was not always fully aware of the progress made by the physical-chemists on carbon black. Reciprocally, the carbon specialists were often ignoring the research carried out on soot in flames. One objective of this workshop was to stimulate discussions between these two scientific communities. During the preparation of the meeting, and especially during the review process by the Material Science Committee of the Scientific Affairs Division of N.A.T.O. the toxicological aspect emerged as being an important component to be addressed during the workshop. To reflect these preoccupations we invited biologists, physical chemists and engineers, all leaders in their field. The final programme is a compromise of the different aspects of the subject and was divided in five sessions.
This book provides an overview on the molecular mode of action of carcinogenic polycyclic aromatic hydrocarbons (PAHs). PAHs are by-products arising from incomplete combustion of organic matter that are frequently released into our environment, and thus are ubiquitously detectable. Many PAHs are strong carcinogens in rodent bioassays and have been linked to increased incidences of various types of cancer in humans. The present book covers all aspects of PAH-induced carcinogenesis; it is a collection of articles written by some of the most recognizable PAH researchers, reviewing the present knowledge in this field. The topics include: exposure to and biomonitoring of PAHs in the human population; metabolic activation of PAHs; genotoxicity and repair of PAH-induced DNA damage; and factors modulating individual susceptibility to the deleterious effects of PAHs.
A core text on principles, laboratory/field methodologies, and data interpretation for fluorescence applications in aquatic science, for advanced students and researchers.
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.
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.