Download or read book tude de la d gradation par photolyse directe de pesticides written by Ahmad Rifai and published by . This book was released on 2013 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: Les pesticides appartiennent à la grande famille des polluants organiques. Ils sont destinés à lutter contre les parasites des cultures au sens large.La diffusion des pesticides dans la nature engendre une pollution des différents compartiments de la biosphère (eau, sol et atmosphère) et peut induire des effets toxiques aigus sur les êtres vivants de la biomasse terrestre et aquatique. Il est aujourd'hui démontré que certains pesticides sont des perturbateurs endocriniens et présentent en particulier des effets cancérogènes et mutagènes chez l'être humain. Les pesticides peuvent subir différents processus de transformation dans le cycle biologique naturel (biodégradation, volatilisation, irradiation solaire...) ou suite aux traitements appliqués dans les filières de potabilisation des eaux naturelles et dans les stations de retraitement des eaux usées. La présence de produits de dégradation de pesticides dans notre environnement est d'autant plus alarmante que leurs structures et leurs toxicités potentielles demeurent généralement inconnues. Des molécules qui appartiennent à deux familles de pesticides ont été choisies pour cette étude : les herbicides, représentés par le metholachlore, et les fongicides, représentés par la procymidone, le pyrimethanil et le boscalid. Le premier volet de la thèse a porté sur le développement d'une stratégie analytique permettant de caractériser les structures de composés issus de la dégradation par photolyse de ces pesticides. Le deuxième volet a porté sur l'estimation de la toxicité des produits de dégradation à l'aide d'une base de test in silico. L'identification des produits de dégradation a été réalisée grâce à deux techniques d'analyses complémentaires : la chromatographie en phase gazeuse couplée à un spectromètre de masse "multi étapes" (GC-MSn) et la chromatographie en phase liquide couplée à un spectromètre de masse en tandem (LC-MS/MS). L'estimation de la toxicité des produits de dégradation a été réalisée grâce au programme T.E.S.T. QSAR récemment développés pour tenter de prévoir la toxicité des molécules. La stratégie d'élucidation structurale des produits de dégradation des pesticides étudiés est basée sur l'étude des mécanismes de fragmentation des molécules mères des produits de dégradation. La masse molaire des molécules mères a été précisée par l'identification des masses sur charge (m/z) des ions pseudo moléculaires obtenus à l'aide des différentes modes d'ionisations en spectrométrie de masse : ionisation électronique (EI) et ionisation chimique (CI) en GC-MS et ionisation par électronébulisation (ESI) en LC-MS. La stratégie utilisée pour l'élucidation structurale des produits de dégradation est avérée très efficace, la plupart des structures chimiques des produits formés ayant été élucidées. Une étude cinétique a été réalisée pour visualiser l'apparition et la disparition des produits de dégradation durant la photolyse et pour donner une idée sur le taux de disparition de la molécule mère pour chaque pesticide. Les résultats de photolyse ont montré que le méthalochlore, le procymidone et le boscalid ont été dégradés sous irradiation après un certain temps en libérant des produits de dégradation avec des structures proches ou différentes des molécules mères. Tandis que le pyrimethanil a présenté une grande stabilité pendant 8 heurs d'irradiation (quantité restante après irradiation est de 60%) et a donné des produits de dégradation avec des quantités modérées. Concernant l'estimation de la toxicité, la plupart des produits de dégradation identifiés présentent des toxicités équivalentes ou plus importantes que celles des molécules d'origine. Les méthodes chimiques d'analyses utilisées et l'estimation de toxicités des produits de dégradations identifiés sont avérées complémentaires et indispensables pour mettre en évidence la présence d'autres produits polluants toxiques qui émergent dans l'environnement sans vrai contrôle

Download or read book Contribution l tude du devenir de deux insecticides dans l environnement written by Gae͏̈lle Goutailler and published by . This book was released on 2001 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt: La contamination des milieux naturels par les pesticides est un problème d'actualité. Ce travail a pour objectif d'évaluer le comportement et le devenir dans l'environnement de deux insecticides de structure chimique voisine la cyromazine et le dicyclanil. L'adsorption de ces matières actives sur trois constituants du sol, argile, silice et oxyde de fer, a été quantifiée suite au tracé de cinétiques et d'isothermes d'adsorption. Les constantes de partage sol/eau, Kd et les constantes de Freundlich, Kf ont été déterminées pour chaque couple solution de pesticide/adsorbant. L'influence des paramètres pH et force ionique sur l'adsorption a été évaluée. L'argile présente, dans la majorité des cas étudiés, la plus forte rétention vis-à-vis des deux pesticides. Le dicyclanil apparaît globalement mieux retenu que la cyromazine. Les constantes d'acidité des deux pesticides ont été mesurées ainsi que la capacité de ces molécules à former des complexes en présence de divers cations métalliques : le cuivre(II), le cadmium(II) et le zinc(II). Seul le cuivre forme un complexe, de très faible stabilité. La décomposition dans l'eau de la cyromazine et du dicyclanil par le rayonnement solaire a été simulée au laboratoire. L'efficacité de la photocatalyse comme moyen de dépollution d'eaux contaminées par l'un de ces pesticides a également été déterminées en présence de dioxyde de titane. Dans chaque cas, les cinétiques de dégradation et de minéralisation en ions nitrate et ammonium, ainsi que la formation d'acides carboxyliques ont été suivies au cours de l'irradiation. La caractérisation de nombreux produits de dégradation a permis de proposer des voies de dégradation pour chacun des pesticides par photolyse, et par photocatalyse.

Download or read book Contribution l tude de d gradation in situ des pesticides par proc d s d oxydation avanc s faisant intervenir le fer written by Mohamed Chakib Edelahi and published by . This book was released on 2004 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: Les procédés dits d’oxydation avancés (POA) permettent la dégradation totale (minéralisation) en milieu aqueux des molécules organiques toxiques pour l’homme et pour l’environnement. Le procédé Electro-Fenton qui fait partie des POA est appliqué dans le cadre de ce travail à la minéralisation des solution aqueuses d'herbicides chlorophénylurées. Les performances de ce procédé ont été comparés avec d'autres procédé POA fraisant intervenir les ions de fer (ferreux ou ferriques) tels que le réactif de Fenton et le procédé photo-Fenton. Dans le cas des molécules étudiées (diuron, monuron et fénuron), il a été montré que le taux de minéralisation par le procédé Fenton (Fe2+/H2O2) augmente avec l’augmentation des doses des réactifs et du temps de réaction. Dans le cas de la dégradation photochimique (irradiation UV), la vitesse de dégradation et le taux de minéralisation sont très faibles. La vitesse de dégradation des molécules mères et le taux de minéralisation des solutions d’herbicides étudiés peuvent être significativement augmentés par le couplage de la photochimie le réactif de Fenton (Fe2+/ H2O2). Ce couplage permet aussi de diminuer la durée d’irradiation et faire économiser d’énergie. Dans le cas du procédé Electro-Fenton, la cinétique de dégradation et de minéralisation dépend des paramètres expérimentaux tels que la concentration du catalyseur, l’intensité du courant appliqué, le pH du milieu, etc. La réactivité des chlorophénylurées vis-à-vis des radicaux hydroxyles varie en fonction du nombre d’atomes de chlore substitués sur le cycle aromatique. La vitesse de réaction de dégradation croît dans l’ordre suivant : diuron (2 Cl substitués), monuron (1 Cl substitué) et fénuron (sans Cl substitué. L’étude de la minéralisation de ces herbicides a montré que les taux d’abattement de carbone organique en terme de DCO dépassent les 90% pour une durée de traitement de 3 heures dans le cas du procédé Electro-Fenton. Le mécanisme de minéralisation des herbicides chlorophénylurées est initié par l’attaque des radicaux hydroxyles de la molécule de départ sur deux sites : le groupement N-terminal et le cycle aromatique générant des sous-produits. Plusieurs sous-produits de dégradation aromatiques qui sont principalement issus d’une oxydation du groupement N-terminal suivie d’une hydroxylation du cycle aromatique et de substitution d’atomes de chlore sur le cycle aromatique ont été identifiés. Des oxydations successives mènent à l’ouverture oxydante du cycle aromatique avec la formation des acides carboxyliques et ions minéraux. Une comparaison des performances de minéralisation par les différents procédés étudiés a montré que les procédés photo-Fenton et Electro-Fenton permettent d’atteindre des taux de minéralisation très important (de l’ordre de 93%). Le procédé Electro-Fenton semble être favorisé avec non utilisation de réactifs chimiques et une faible consommation d’énergie électrique

Download or read book Advanced Oxidation Processes for Water and Wastewater Treatment written by Simon Parsons and published by IWA Publishing. This book was released on 2004-03-01 with total page 370 pages. Available in PDF, EPUB and Kindle. Book excerpt: The suitability of Advanced Oxidation Processes (AOPs) for pollutant degradation was recognised in the early 1970s and much research and development work has been undertaken to commercialise some of these processes. AOPs have shown great potential in treating pollutants at both low and high concentrations and have found applications as diverse as ground water treatment, municipal wastewater sludge destruction and VOCs control. Advanced Oxidation Processes for Water and Wastewater Treatment is an overview of the advanced oxidation processes currently used or proposed for the remediation of water, wastewater, odours and sludge. The book contains two opening chapters which present introductions to advanced oxidation processes and a background to UV photolysis, seven chapters focusing on individual advanced oxidation processes and, finally, three chapters concentrating on selected applications of advanced oxidation processes. Advanced Oxidation Processes for Water and Wastewater Treatment will be invaluable to readers interested in water and wastewater treatment processes, including professionals and suppliers, as well as students and academics studying in this area. Dr Simon Parsons is a Senior Lecturer in Water Sciences at Cranfield University with ten years' experience of industrial and academic research and development.

Download or read book Coal Tar Creosote written by C. Melber and published by WHO. This book was released on 2004 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: On cover: IPCS International Programme on Chemical Safety. Published under the joint sponsorship of the United Nations Environment Programme, the International Labour Organization and the World Health Organization, and produced within the framework of the Inter-organization Programme for the Sound Management of Chemicals (IOMC)

Download or read book Potential Applications of Concentrated Solar Energy written by National Research Council and published by National Academies Press. This book was released on 1991-02-01 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book assesses the current state of the field in a number of potential applications and discusses technologies for which concentrated solar energy might be utilized. It contains all the papers submitted by the speakers as well as summaries of the presentations and discussions that followed each session.

Download or read book Water Research written by and published by . This book was released on 1994 with total page 832 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Some Chemicals Present in Industrial and Consumer Products Food and Drinking water written by IARC Working Group on the Evaluation of Carcinogenic Risks to Humans and published by IARC Monographs on the Evaluat. This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume of the IARC Monographs provides an assessment of the carcinogenicity of 18 chemicals present in industrial and consumer products or food (natural constituents, contaminants, or flavorings) or occurring as water-chlorination by-products. The compounds evaluated include the widely used plasticizer di(2-ethylhexyl) phthalate and the food contaminant 4-methylimidazole. In view of the limited agent-specific information available from epidemiological studies, the IARC Monographs Working Group relied mainly on carcinogenicity bioassays, and mechanistic and other relevant data to evaluate the carcinogenic hazards to humans exposed to these agents.

Download or read book Global Atmospheric Change and its Impact on Regional Air Quality written by Ian Barnes and published by Springer Science & Business Media. This book was released on 2002-11-30 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt: The NATO ARW in Irkutsk was an excellent occasion for the coming together of Eastern and Western scientists who are involved in tropospheric science; the workshop has greatly contributed to the scientific and social understanding among the participants from the many different countries. Many new personal contacts were made which will help to strengthen future collaborations. In particular, the Lake Baikal area and the Limnological Institute offer splendid opportunities for environmental research which, in part, is already on going. For most participants it was the first time to see the impressive nature of the Lake Baikal region. Hopefully, there will be a chance for a follow-up event in Siberia where researchers from the East and West can again meet and engage in fruitful scientific dialogue. The book contains extended abstracts of the lectures and the poster presentations presented at the NATO ARW "Global Atmospheric Change and its Impact on Regional Air Quality" Irkutsk, Lake Baikal, Russian Federation, August 21-27, 2001. The ARW was composed of 22 oral presentations by key lecturers and 6 additional shorter oral presentations from participants. In a special poster session the 36 poster contributions were presented and discussed. Unfortunately not all contributors submitted extended abstracts, however, to compensate two contributions have been added from 2 participants who were originally invited but were unable to attend.

Download or read book Heterogeneous and Liquid Phase Processes written by Peter Warneck and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: The "European Experiment on the Transport and Transformation of Environmentally Relevant Trace Constituents over Europe" (EUROTRAC) was established in 1986 to tackle the scientific problem and combine the expertise, knowledge and resources in Europe, in order to apply them over a large region covering the greater part of the continent. EUROTRAC is a coordinated multidisciplinary scientific research project involving field measurements, laboratory studies, instrument development and development of comprehensive computer models for the simulation of the physical and chemical processes in the lower atmosphere.

Download or read book Pollution Abstracts written by and published by . This book was released on 1996 with total page 698 pages. Available in PDF, EPUB and Kindle. Book excerpt: Indexes material from conference proceedings and hard-to-find documents, in addition to journal articles. Over 1,000 journals are indexed and literature published from 1981 to the present is covered. Topics in pollution and its management are extensively covered from the standpoints of atmosphere, emissions, mathematical models, effects on people and animals, and environmental action. Major areas of coverage include: air pollution, marine pollution, freshwater pollution, sewage and wastewater treatment, waste management, land pollution, toxicology and health, noise, and radiation.

Download or read book Enzyme Handbook 4 written by Dietmar Schomburg and published by Springer Science & Business Media. This book was released on 2013-11-11 with total page 1037 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent progress in enzyme immobilisation, enzyme production, coenzyme regeneration and enzyme engineering has opened up fascinating new fields for the potential application of enzymes in a large range of different areas. As more progress in research and application of enzymes has been made the more apparent has become the Iack of an up-to-date overview of enzyme molecular properties. The need for such a data bank was also expressed by the EC-task force "Biotechnology and Information". Therefore we started the development of an enzyme data information system as part of protein-design activities at GBF. The present book "Enzyme Handbook" represents the printed version of this data bank. ln future it is also planned to make a com puter searchable version available. The enzymes in the Handbook are arranged according to the 1984 Enzyme Commission Iist of enzymes and later supplements. Same 3000 "different" en zymes are covered. Frequently very different enzymes are included under the same E. C. number. Although we intended to give a representative overview on the molecular variability of each enzyme, the Handbook is not a com pendium. The readerwill have to go to the primary Iiterature for more detailed information. Naturally it is not possible to cover all numerous, up to 40 000, Iiterature references for each enzyme if data representation is to be concise as is intended.

Download or read book Transport and Chemical Transformation of Pollutants in the Troposphere written by Peter Borrell and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 446 pages. Available in PDF, EPUB and Kindle. Book excerpt: A major environmental concern is the increasing burden on all scales of photo-oxidants, acidifying substances and potential nutrients in the troposphere. These lead to episodes of summer smog, and appreciable damage to eco-systems both on land and at sea. Underlying the environmental effects is the complex scientific problem of linking the man-made and biological emissions to the myriad chemical reactions that transform the pollutants as they are transported to and deposited in the surroundings and also pristine areas remote from the sources. The project, the scientific results of which are described in this book, was set up to study the problem in an inter-disciplinary way by co-ordinating the work of more than 150 research groups in some 20 countries.

Download or read book An Introduction to Radiation Chemistry written by John William Tranter Spinks and published by Wiley-Interscience. This book was released on 1990-05-24 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text on radiation chemistry covers a number of topics, including the development of radiation chemistry, sources of high-energy radiation, dosimetry, organic materials and solids and the applications of high-energy radiation in chemical synthesis and in commercial processes.

Download or read book Wastewater Reuse and Management written by Sanjay K. Sharma and published by Springer Science & Business Media. This book was released on 2012-11-06 with total page 525 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past 50 years the volume of wastewater has grown exponentially as a result of the increasing world population and the expansion of industrial developments. Researchers all over the world have been trying to address this issue suitably in order to fight water scarcity; yet, it is only recently that wastewater recycling has caught their attention as an effective and responsible solution. Wastewater is a resource that can be adequately treated to successfully satisfy most water demands as well as decreasing wastewater discharges and preventing pollution. This book presents the studies of some of the most prestigious international scientists and gathers them in three different sections: Wastewater Management and Reuse, Wastewater Treatment options and Risk Assessment. The result is an insightful analysis of waste water management, its treatments, and the processes that have been studied, optimized and developed so far to sustain our environment. Wastewater Reuse and Management represents a valuable resource to academic researchers, students, institutions, environmentalists, and anyone interested in environmental policies aimed at safeguarding both the quality and the quantity of water.

Download or read book Chemical Water and Wastewater Treatment VI written by Hermann H. Hahn and published by Springer. This book was released on 2011-09-18 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: For the ninth Gothenburg Symposium time design and operation engineers as well as supervising and funding administrators in chemical water and waste water treatment, have come together to exchange ideas, experiences and personal views on issues of water and waste water management. While the main thrust of past symposia was in the description of the technological know-how of existing chemical unit-operations in water technology this ninth symposium focuses in addition on aspects of overall energy and mass flux analyses, the strive for more and more sustainable solutions (not only in technological turns) and public private partnership in all areas of water management. As the symposium in its effort to address also different geographical areas and therefore different water problems moved to Istanbul in Turkey a special effort was made in developing a platform for industrial water management.

Download or read book The Music Learning Profiles Project written by Radio Cremata and published by Routledge. This book was released on 2017-11-22 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Music Learning Profiles Project: Let’s Take This Outside uses ethnographic techniques and modified case studies to profile musicians active in a wide range of musical contexts not typically found in traditional music education settings. The book illuminates diverse music learning practices in order to impact music education in classrooms. It goes on to describe the Music Learning Profiles Project, a group of scholars dedicated to developing techniques to explore music learning, which they call "flash study analysis." Twenty musicians were interviewed, invited to talk about what they do, how they learned to do it, and prompted to: Identify key learning experiences Discuss their involvement in formal learning environments Predict how they see musicking practices passing to a future generation The Music Learning Profiles Project offers a nuanced understanding of the myriad approaches to music learning that have emerged in the early part of the twenty-first century.