Perfluorinated carboxylates (PFCAs) and perfluorinated sulfonates (PFSAs) are found almost ubiquitously in the environment, however their direct production and use is limited. The focus of this thesis was to explore connections between observed contamination with the manufacture and/or use of commercial fluorochemical materials. Perfluorinated sulfonamides (PFSAms) are semi-volatile materials used in the manufacture of commercial fluorochemicals. Investigations into the atmospheric fate of a model PFSAm found atmospheric lifetimes that allow transport to remote environments, potentially through a novel N–dealkylation product. A suite of PFCAs, as well as the PFSA from loss of the amide moiety, were also observed. This investigation demonstrated that PFSAm atmospheric oxidation will contribute to PFCA and PFSA contamination in remote locations, including the Arctic. The perfluorinated phosphonates (PFPAs) were used as defoaming additives in pesticide formulations. Using novel extraction and analysis methods, widespread PFPA contamination was detected in Canadian surface waters and wastewater treatment plant (WWTP) effluent. As fully fluorinated acids, the PFPAs are a new class of perfluorinated acid discovered in the environment. Uptake and elimination parameters determined in the rat demonstrate the potential for human PFPA exposure, as these chemicals are bioavailable. Processes governing the pharmacokinetics and disposition of perfluorinated acids in the body are poorly understood. Novel heteronuclear nuclear magnetic resonance experiments identified human serum albumin as the major site of interaction. Competitive binding experiments found the PFCAs displaced the endogenous human serum albumin ligand, 13C1-oleic acid, at lower concentrations than established ligands. The strong association observed between the PFCAs and human serum albumin may inform observed human toxic endpoints and long elimination half-lives. The polyfluoroalkyl phosphates (PAPs) are used in food-contact paper packaging. High PAP concentrations were discovered in human sera, waste paper fibres and WWTP sludge, establishing human exposure to these chemicals. Biotransformation from PAP to PFCA was investigated in a rat model. The serum kinetics and PFCA products observed, suggest PAP exposure may be a significant source of human PFCA contamination. The concerted approach of environmental monitoring with investigations of atmospheric and biological fate allowed strong associations to be made between commercial fluorochemical sources and observed contamination.

Perfluoropolyethers (PFPEs) are used in a remarkably large number of industrial applications including thin-film lubricants, greases, heat transfer fluids, cosmetics, and EPA-approved food contact paper coatings and are marketed for their chemical inertness. Although desired industrially, it is also the property of most environmental concern. The lack of literature concerning the environmental impact of these compounds suggests a need to assess and characterize their environmental fate and transport. This work describes efforts to develop methods to characterize, identify and quantify various congeners of PFPEs through chromatographic, mass spectral and nuclear magnetic resonance techniques. The PFPEs exhibited unusual behavior during ionization by ESI, suggesting the possibility of structural lability during analysis. A preliminary assessment of the environmental degradation of a PFPE-phosphate congener is also described, which showed rapid sorption to sewage sludge particulate matter and the possible presence of multiple PFPEs present in the technical product mixture used for analysis.

The assement of chemical persistence is an important part of legislative protection of the environment and human health. Of the vast number of chemicals on the market today few have been properly assessed. The coordination between testing guidelines from different frameworks is limited and especially the methods for determination of biodegradation show poor reproducibility because of their highly complex nature. In order to circumvent the multifactorial assessment methods that involve the use of e.g. soils and sediments an attempt to create a new approach to chemicals assessment was postulated by Green and Bergman in 2005. This approach puts the focus on testing the chemical reactivity of the compound in environmentally relevant transformation/degradation reactions, i.e. reduction, oxidation, hydrolysis-substitution-elimination (hse), radical reactions, and photolysis. These tests are to be performed in controlled abiotic laboratory experiments ensuring that the results reflect the transformation rate of the intended type of reaction for the investigated substance. To achieve an assessment of the presistence of the compound, the test results are then combined with data on physicochemical properties of the compound and a mathematic matrix describing the reactive power of the different types of reactions in each environmental compartment (air, water, soil, and sediment). Thus far methods for testing of oxidation, photolysis, and hydrolysis-substitution-elimination reactions have been developed. Within this thesis a method for determining reduction was developed and further utilised to determine transformation products from reductive debromination of the three nonabrominated diphenyl ethers. The previously established method for hse was evaluated and further developed in a study of selected chlorobenzenes. Some novel brominated flame retardants were investigated using the previously developed photolysis method, and transformation products and quantum yields were determined. All of the papers presented within this thesis intend to build on the project of a new persistency assessment model. The results presented also contributes important information on the properties and transformation of some common organohalogen pollutants. / At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 1: Submitted. Paper 4: Manuscript.

Thesis (Ph.D.)--Harvard University, 2005. / Adviser: Daniel J. Jacob. Includes bibliographical references.

Thesis (Ph. D.)--University of Missouri-Columbia, 1998. / Typescript. Vita. Includes bibliographical references (leaves 86-94). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1998. / Typescript. Vita. Includes bibliographical references (leaves 86-94). Also available on the Internet.

Thesis (Ph.D.)--OGI School of Science & Engineering at OHSU, Oct. 2005. / Includes bibliographical references.

<h2>Abstract</h2><p> </p><p>Bio energy in form of woodchips and sawdust is today commonly stored outdoors in heaps on hardened surfaces, exposed to weather and wind. Any water leaching from these heaps have the potential to be toxic to the environment.</p><p>This paper examines the quality of the water leaching from heaps of four different tree species (oak, pine, maple and beech), by analysing different parameters such as pH, conductivity, colour, COD, BOD₇, tannins & lignins (T&L) and phenols.</p><p>The results show significant higher leaching values of COD, phenols, T&L and colour from oak compared to the other tree species (pine, maple and beech). These leached substances from woodchips and sawdust were shown in the BOD₇ tests and BOD₇/COD ratio values to be hard to biodegrade and are therefore not easily removed from the water.</p><p>Hence it is important that wood-based fuel storage conditions are considered in bio energy generation schemes to ensure that the environmental benefits of using woodchips and sawdust instead of traditional fuel are not offset by the potential harm of inappropriate storage.</p><p>The investigation further showed that leaching of highly toxic substances such as phenols can be up to 10 times higher for one tree type (oak) than another (pine, beech and maple). This difference could potentially be found for other tree species not characterized in this study.  Therefore, it is important to consider the constitution of the heaps to be able to apply appropriate storage conditions to avoid these toxic substances in the leached water reaching sensitive watercourses. As some of these substances are hard to biodegrade the treatment applied need a long retention time.</p><p>Another problem is the carbon: nutrient ratio, this water has a high carbon content compared to phosphorus and nitrogen content which might prevent an efficient biodegradation. Adjusting C:N:P ratio with low cost amendments might raise the performance of the biodegradation in for instance, a constructed wetland.</p>

Made available in DSpace on 2014-06-11T19:35:05Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-04-01Bitstream added on 2014-06-13T20:06:23Z : No. of bitstreams: 1 franciscojunior_we_dr_araiq.pdf: 898887 bytes, checksum: d65b9618bf16da6ada800ae8800374bb (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Que a leitura é essencial em qualquer setor da sociedade, isso é inconteste, mas quais mecanismos regulam esse processo e como professores e pesquisadores podem (ou devem) agir para suplantar problemas associados a essa competência? Qual o papel do leitor durante a leitura e quais procedimentos o tornam mais proficiente? Quais são as contribuições das pesquisas em educação em ciências para questões atinentes à leitura? Quais estratégias de leitura contribuem para a formação de um leitor crítico e de qual forma? Foi essencialmente o anseio de debater tais questionamentos que moveu a presente pesquisa, dividida basicamente em quatro etapas de investigação. A primeira delas consistiu de um levantamento acerca da produção científica relacionada à leitura nos periódicos brasileiros de educação em ciências. Esse levantamento revelou um crescimento das pesquisas nos últimos anos, assim como o uso de estratégias de leitura utilizadas variadas, envolvendo diferentes e criativas propostas de produção de textos conjuntamente à leitura. No entanto, aspectos cognitivos e metacognitivos da leitura não são explorados, o que poderia atuar positivamente para a melhoria do processo. As outras três etapas do trabalho consistiram no planejamento, execução e avaliação de unidades de leitura. Tais unidades de leitura são compostas basicamente por três passos: i) a produção inicial e individual de sentidos; ii) a socialização desses sentidos em grupo; e iii) a transformação dos sentidos a partir da escrita de um novo texto. Na primeira dessas unidades de leitura, é apresentada uma atividade que buscou o desenvolvimento de aspectos relacionados ao funcionamento da ciência, sobretudo a importância dos modelos. Após a leitura do texto, realizada individualmente e em silêncio, foi conduzida uma atividade... / That reading is essential in modern society is undeniable, but it is not clear which mechanisms adjust this process and how teachers and researches can (or should) proceed to supplant problems associated with this competence. What is the role of readers during the reading process and what procedures make them more proficient? Which reading strategies can help developing the critical reading and how do they work? From these questions, the aim of this study is contribute to this discussion. The present research was divided into four parts. The first of them is the study of papers concerning reading in science education published in brazilian journals of this field. This study revealed an improvement of research related to reading in Brazil in the last years, as well as different and creative proposes that involved writing together with reading. However, cognitive and metacognitive aspects were not explored, which could help to improve this process. The other three parts consisted on the organization, execution and evaluation of reading units. These reading units involve three steps: i) an initial sense production; ii) the socialization of these senses in group; and iii) the transformation of these ideas through writing of a new text. As the first reading unit a classroom activity developed with medium level students from a pre-vestibular course in Araraquara-SP is examined. The aim of this activity was to develop aspects concerned to science function, mainly about the models‟ role in science. After reading, conducted individually and in silence, writing activities were developed. Among others, these activities demanded the formulation of questions, commentaries and question answer pairs about the text. In the second proposal conducted in classroom, a reading activity developed with 17 chemistry students from Federal University of Rondonia... (Complete abstract click electronic access below)

Ph.D. / Natural Organic Matter (NOM) consists of a highly variable mixture of products found in various types of water and soils, formed as a result of decomposition of plant and animal material into water. NOM is a precursor for the formation of disinfection by-products (DBPs) during water disinfection. It causes undesirable colour, taste and odour in water. The reduction of NOM affects the capacity of other treatment processes to remove organic micro-pollutants or inorganic species that may be present in the water. The differing levels and composition of NOM in South African water sources in different regions suggests that a water treatment strategy by a treatment plant should address the issues relating to specific NOM and its treatability. Therefore, in order to reduce NOM from water in a water treatment train, the composition of the NOM in the source water must be taken into account, since its composition at any given time may depend on the local prevailing conditions. The primary objective of this study was therefore to characterize NOM present in South African source waters through extensive sampling of representative water types at identified regions in the country and develop a rapid NOM characterization protocol. Water samples were thus collected from eight different water treatment plants broadly located within the five major source water types of South Africa between the periods of February 2010 to June 2011 in five sampling rounds. The sampling campaigns were planned and timed in order to accommodate the dry and the rainy seasons. The water treatment plants sampled were: Loerie (L) Water Treatment Plant, Midvaal (M) Water Treatment Plant, Olifantsvlei (O) Wastewater Treatment Plant, Plettenberg Bay (P) Water Treatment Plant, Rietvlei (R) Water Treatment Plant, Umzoniana (U) Water Treatment Plant, Vereeniging (V) Water Treatment Plant, and the Wiggins (W) Water Treatment Plant. The L water is from a small impoundment, which is fed from the Kouga Dam. The M water is pumped from the Vaal River.