Mono- and di-alkyltins are used extensively as heat stabilizers for processing of poly vinyl chloride (PVC). Tin mercaptide stabilizers are some of the most effective PVC stabilizers available. The main applications for tin stabilizers are building/construction products, such as pipes, fittings, siding and profiles (windows etc.), packaging and flexible PVC plastics. Most PVC products have been and are subjected to landfilling, when their use is terminated. The structure of the polymer itself and the substances used as additives have been a concern for environmental authorities in many countries since long, which also includes their presence in landfills. In the case of the organotin stabilizers their leaching out from (PVC) plastics into the leachate phase of landfills with the risk for further transport to ground and surface waters is in focus. The main objectives of this thesis take their start in this background and, thus, included the elucidation of whether organotin compounds (OTs) in stabilized PVC products contribute to the pool of OTs observed in landfill leachates and if these compounds are degradable by the microorganisms developing under anaerobic landfill conditions. To reach these aims and the research questions raised the forwarded PVC materials were added to muniscipal solid waste (MSW) processed in containers used to simulate the ageing of landfills under forced conditions. These include traditional landfill simulation reactors (LSRs) at a scale of ca 100 L and also at a smaller scale ca 5 L constructed for the purpose of this study, i.e. the modular environmental test system (METS). The latter were used to investigate temperature effects on the possible release of OTs from different types of PVC materials. The capacity by microorganisms in landfill environments were used to investigate their capacity to degrade or transform organotin stabilizer compounds focused on in this thesis. Differences in this capacity in relation to the ageing of landfills and exposure to the alkyltin stabilizers were studied with microorganisms sampled from LSRs spiked with PVC over time and from landfill site. Access to sensitive and reliable equipment and analytical protocols for the analysis of OTs and their transformation intermediates and end products are prerequisites for this kind of studies. This necessitated an adoption and adaptation of analytical methods for the low concentrations occurring in the environment. Two methods were established and well served the requirements. Indeed OTs migrated out from especially flexible PVC materials, while rigid PVC was less prone for OT release as judged from the METS simulations. The METS studies showed that the OT release increase substantially at higher temperatures and especially so when the temperature was higher than the glass transition of the PVC.materials. The organotin stabilizers were transformed, partly or completely degraded, by anaerobic microorganisms derived from landfill environments. Upon prolonged exposure to OTs leaching from PVC in LSR simulations the microorganisms displayed a higher efficiency in degradation of the leached OTs. The microorganisms would methylate inorganic tin and metyltin present in the MSW material as well as perform dealkylation depending on the tin concentrations prevailing. During these studies it was discovered that the organotin stabilzers were inhibiting the methanogens and fermentative bacteria, which lead to a retardation of the anaerobic mineralisation of the MSW in the assays. An in depth study revealed that the OTs themselves but also their ligands and degradation products from these together effected the inhibition. However, given the extent of leaching in relation to the water flows in landfills, the concentrations will mainly be too low to pose any risks to the surrounding environment.

Perfluorinated carboxylates (PFCAs) are persistent and ubiquitous in the environment. Humans are exposed to PFCAs through direct and indirect sources, although the relative importance of each is uncertain. Direct sources of PFCAs have been attributed to two primary fluorochemical manufacturing processes: electrochemical fluorination (ECF) and telomerization. A focus of this thesis was to elucidate an additional direct source of PFCAs resulting from the direct fluorination of polyolefin materials. High density polyethylene bottles with varying levels of fluorination were observed to contain significant amounts of PFCAs, particularly those with carbon chain-lengths ≤ C6, marking an unexplored source of PFCA exposure. PFCAs are also produced indirectly from the biotransformation of fluorotelomer-based compounds, such as polyfluoroalkyl phosphate esters (PAPs) and fluorotelomer alcohols (FTOHs). During this transformation process, two predominant classes of metabolic intermediates are formed: the fluorotelomer unsaturated aldehydes (FTUALs) and the fluorotelomer unsaturated carboxylic acids (FTUCAs). Another focus of this thesis was to examine the reactivity of FTUALs and FTUCAs with endogenous nucleophiles such as glutathione (GSH), select amino acids, and model proteins. FTUALs formed adducts with all nucleophiles examined, where those having shorter carbon chain lengths (i.e. 6:2 and 8:2 FTUAL) were more reactive than longer carbon chains (i.e. 10:2 FTUAL). By contrast, FTUCAs had comparably limited reactivity; although FTUCAs showed mild reactivity with GSH, they did not react with any other nucleophiles. In vitro and in vivo experiments were carried out to determine the extent of protein binding formed from the biotransformation of fluorotelomer-based compounds, including the 8:2 FTOH and the 6:2 PAP diester. A significant portion of these biotransformations yielded covalent protein binding at nmol/mg protein concentrations. Protein adducts were observed predominantly in rat liver and also in plasma and kidney. The formation of reactive intermediates may be toxicologically important through protein deactivation. Cellular toxicity of FTUALs was significantly higher compared to PFCAs and the acid metabolic intermediates (i.e. FTUCAs). The EC50 values calculated from dose-response incubations were dependant on chain length and functional group. The work in this thesis examined an unexplored consequence of indirect exposure to PFCAs, potentially impacting the relative importance of PFCA exposure sources.

Perfluorinated carboxylates (PFCAs) are persistent and ubiquitous in the environment. Humans are exposed to PFCAs through direct and indirect sources, although the relative importance of each is uncertain. Direct sources of PFCAs have been attributed to two primary fluorochemical manufacturing processes: electrochemical fluorination (ECF) and telomerization. A focus of this thesis was to elucidate an additional direct source of PFCAs resulting from the direct fluorination of polyolefin materials. High density polyethylene bottles with varying levels of fluorination were observed to contain significant amounts of PFCAs, particularly those with carbon chain-lengths ≤ C6, marking an unexplored source of PFCA exposure. PFCAs are also produced indirectly from the biotransformation of fluorotelomer-based compounds, such as polyfluoroalkyl phosphate esters (PAPs) and fluorotelomer alcohols (FTOHs). During this transformation process, two predominant classes of metabolic intermediates are formed: the fluorotelomer unsaturated aldehydes (FTUALs) and the fluorotelomer unsaturated carboxylic acids (FTUCAs). Another focus of this thesis was to examine the reactivity of FTUALs and FTUCAs with endogenous nucleophiles such as glutathione (GSH), select amino acids, and model proteins. FTUALs formed adducts with all nucleophiles examined, where those having shorter carbon chain lengths (i.e. 6:2 and 8:2 FTUAL) were more reactive than longer carbon chains (i.e. 10:2 FTUAL). By contrast, FTUCAs had comparably limited reactivity; although FTUCAs showed mild reactivity with GSH, they did not react with any other nucleophiles. In vitro and in vivo experiments were carried out to determine the extent of protein binding formed from the biotransformation of fluorotelomer-based compounds, including the 8:2 FTOH and the 6:2 PAP diester. A significant portion of these biotransformations yielded covalent protein binding at nmol/mg protein concentrations. Protein adducts were observed predominantly in rat liver and also in plasma and kidney. The formation of reactive intermediates may be toxicologically important through protein deactivation. Cellular toxicity of FTUALs was significantly higher compared to PFCAs and the acid metabolic intermediates (i.e. FTUCAs). The EC50 values calculated from dose-response incubations were dependant on chain length and functional group. The work in this thesis examined an unexplored consequence of indirect exposure to PFCAs, potentially impacting the relative importance of PFCA exposure sources.

No description available.

Persistent organic pollutants are a well-known threat to the environment. Substances such as polycyclic aromatic hydrocarbons and chlorinated organic compounds in contaminated soil and groundwater can have severe and long-lasting effects on health in animals and humans. There is an urgent need for the development of safe technologies for their effective removal. Originally developed for mineral processing, mechanical treatment by ball milling is an extremely versatile technique for the degradation of toxic compounds. Reactive milling can rapidly destroy organic compounds without producing hazardous wastes. Complete breakdown of the organic molecules is achieved after relatively short milling times. Successful tests were conducted on polychlorobiphenyls (PCBs), DDT, DDD, DDE, Dieldrin and hexachlorobenzene with a conversion yield in the of greater than 99% (Hall et al., 1996; Monagheddu et al., 2000; Zhang et al., 2001; Zhang et al., 2002; Tanaka and Zhang, 2003; Pizzigallo et al., 2004; Nomura et al., 2005; Bellingham, 2006).In this study reactive ball milling was used to investigate the destruction of two classes of persistent organic pollutants environmental contaminants. The compounds studied are either known environmental pollutants or simple analogues. These were chosen as being representative of pollutants to investigate the pathway using ball milling destruction and in most cases were relatively small molecules so that the intermediates could be more easily identified. The first class of compounds was polycyclic aromatic compounds. Some smaller members of this class such as naphthalene, anthracene were investigated. The second class of compounds were some analogues of environmentally hazardous hydroxylated and halogenated compounds such as chloronaphthalene, bromonaphthalene, 1- naphthol, 2-naphthol and pentachlorophenol under reactive milling using GCMS analysis of the degradation pathway. Destruction efficiencies greater than 99% have been achieved for a number of organic compounds. Several different intermediates have been identified during the milling degradation. There was also some evidence from this study that halogens could be transferred between compounds during milling. The final products of the milling destruction of these compounds are an amorphous carbon residue and inorganic chloride or bromides. It was proposed that large amounts of halogens could be found however the results showed that small amounts detected. At early stages of milling a number of intermediate breakdown products were detected which were destroyed on extended milling. The core objective of this research was to clarify the reaction mechanisms pathways used of more complex polycyclic aromatic hydrocarbons and aromatic organ halogen compounds. This study is a part of a long-term research project on the destruction of toxic organic compounds by reactive milling.

Thesis (Ph. D.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed Nov. 21, 2007). Vita. Includes bibliographical references.

Thesis (M.S.)--Western Kentucky University, 2009. / Includes bibliographical references (leaves 69-70).

Thesis (Ph.D.)--Duquesne University, 2005. / Title from document title page. Abstract included in electronic submission form. Includes bibliographical references and index.

Orientador: Amauri Antonio Menegário / Banca: Carlos Renato Corso / Banca: Eduardo de Almeida / Banca: Marcelo Loureiro Garcia / Banca: Yadira Ansoar Rodríguez / Resumo: A técnica de difusão em filmes finos por gradiente de concentração (DGT) tem se consolidado como uma excelente ferramenta analítica capaz de fornecer concentrações lábeis por tempo, pré-concentração dos analitos e amostragem in situ, porém a aplicação desta técnica em águas de drenagem ácida de mina (DAM) é complicada devido à redução da adsorção do amostrador tradicional (resina ligante Chelex-100) para metais em baixo pH. Este estudo, avalia a utilização da técnica DGT para determinação das concentrações lábeis de Al, Cd, Cu, Mn, Ni, Pb U e Zn em águas de DAM, empregando novos agentes ligantes preparados a partir de biomassas (cascas de banana, borra de café e sementes de moringa) impregnadas em agarose. As medições DGT foram realizadas em soluções padrão em laboratório e in situ. Resultados laboratoriais mostram que os agentes ligantes podem ser empregados em águas com pH baixo (pH 3,5) para os íons Cd, Cu, Ni, Pb e Zn. Já os íons Al, Mn e U não apresentaram linearidade nas curvas de imersão para nenhuma biomassa pesquisada. Para a análise de amostras in situ de DAM, houve baixas recuperações dos íons Cd, Cu, Ni e principalmente para Zn com 5,7% da fração solúvel com o gel de agarose-moringa, podendo indicar a baixa eficiência dos agentes ligantes ou algum efeito matriz inerente durante a determinação por ICPOES. Por outro lado, houve recuperações satisfatórias para a imersão em amostras do Rio Corumbataí e do Rio Piracicaba, ressaltando o emprego destes agentes ligantes pesquisados em matrizes aquáticas diferentes das matrizes de DAM. Este estudo mostra que o uso da técnica DGT pode ser estendido para águas com pH baixo (desde que sejam avaliados as limitações e condições de contorno avaliadas neste estudo) podendo ser uma ferramenta útil para o monitoramento em tempo integrado de concentrações lábeis ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The diffusive gradients in thin films (DGT) technique has consolidated as an excellent analytical tool capable of providing labile concentrations by time, analytical preconcentration and in situ sampling, but the application of this technique in acid mine drainage waters (AMD) is limited by the reduction of adsorption of the traditional binding layer (Chelex-100 chelating resin) to metals at low pH. This study proposes the use of the DGT technique to determine the concentrations of Al, Cd, Cu, Mn, Ni, Pb U and Zn in AMD using new binding agents prepared from biomass (Musa cavendishi banana peel, spent coffee grounds and shelled Moringa Oleifera seeds) impregnated with agarose. DGT measurements were performed in laboratory standard solutions and in situ. Laboratory results showed that the binding agents can be used in waters with low pH (pH 3.5) for Cd, Cu, Ni, Pb and Zn. Al, Mn and U ions did not present linearity in the deployment curves for any biomass studied. For the analysis of in situ AMD samples, there were low recoveries of the Cd, Cu, Ni, and mainly Zn ions with 5.7% of the soluble fraction with the agarose-moringa gel, indicating the low efficiency of the binding agents at low values pH or some inherent matrix effect during determination by ICP-OES. On the other hand, there were satisfactory recoveries for deployment in samples from the Corumbataí River and the Piracicaba River, highlighting the use of these binding layers in aquatic matrices other than AMD matrices. This study shows that the use of the DGT technique can be extended to waters with low pH (provided that the limitations and contour conditions evaluated in this study are evaluated) and can be a useful tool for the integrated time monitoring of labile concentrations in different aquatic systems / Doutor

Orientador: Denise Bevilaqua / Orientador: Oswaldo Garcia Júnior (in memorian) / Banca: Luis Gonzaga Santos Sobral / Banca: Domingo Cantero Moreno / Resumo: Neste trabalho foram realizados ensaios para o estudo da viabilidade da conversão de lavadores químicos (tecnologia química muito utilizada para a remoção de H2S) em biofiltros percoladores para a remoção de H2S. Foi investigado o efeito inibitório da concentração de sulfato no meio de recirculação de nutrientes, o efeito do pH, da vazão de recirculação de nutrientes, da concentração de alimentação de H2S na corrente gasosa e do tempo de residência na eficiência de remoção de H2S em dois biofiltros percoladores, um recheado com espuma de poro aberto de poliuretano e o outro com anéis de Pall de polipropileno. Durante a etapa de imobilização dos micro-organismos foi observado, experimentalmente, que o anel de Pall de polipropileno não é um bom suporte para a imobilização de Thiobacillus denitrificans e, portanto, no caso da conversão de um lavador químico constituído por um leito de recheio de anéis de Pall em um biofiltro percolador, seria apropriada a substituição deste suporte por espuma de poro aberto de poliuretano, por exemplo, que demonstrou ser um bom suporte para a formação do biofilme. Durante o estudo do efeito do pH observou-se que o aumento de pH aumenta a porcentagem de remoção de H2S, sendo que nas condições utilizadas, o intervalo de pH ótimo ficou entre 7,6 - 8,5. O efeito inibitório da concentração de sulfato foi observado a partir de 16,5 g L-1 no biofiltro de espuma de poro aberto de poliuretano e de 13,0 g L-1 no biofiltro de anéis de Pall de polipropileno. Os efeitos da vazão de recirculação de nutrientes e do tempo de residência do gás foram mais evidentes no biofitro de anéis de Pall comparado a espuma de poro aberto, devido, provavelmente, às características do suporte. No biofiltro de espuma de poro aberto, a diminuição do tempo de residência afetou a... (Resumo completo, clicar acesso eletrônico baixo) / Abstract: In this work experiments were carried out in order to study the viability of conversion of chemical scrubbers (current technology) to biotrickling filter for removing H2S. Many parameters were investigated, such as, the inhibitory effect of sulfate concentration in the nutrient recirculation, the effect of the pH, the flow rate of recirculating nutrient, the inlet H2S concentration and the gas stream residence time in the H2S removal capacity in two biotrickling filter. One of them was packaged with open pore polyurethane foam and other with polypropylene Pall rings. During and after the immobilization stage it was observed, experimentally, that polypropylene Pall rings is not a good support for immobilizing Thiobacillus denitrificans. Thus, in the case of a chemical packaged scrubber conversion using such support in a biotrickling filter, it would be appropriate to replace it by open pore polyurethane foam, for instance, which demonstrated to be a better support to the biofilm to establish. It was shown that increasing the pH an increase in the H2S removal was detected. In this experimental work conditions, the optimum pH range was from 7.6 to 8.5. The inhibitory effect of the sulfate concentration was observed from 16.5 g L-1 in the open pore polyurethane foam biofilter and 13.0 g L-1 in the polypropylene Pall rings biofilter. The effects of the flow rate of the recirculating nutrient and the gas residence time were more evident in the Pall ring biofilter when compared with the open pore foam, probably due to the support characteristics. In the open pore foam biofilter, decreasing the residence time the H2S removal percentage was affected only for less than 9 s, whereas in the Pall rings biofilter, before 33 s. In both biofilters as lower the residence time, lower the H2S removal percentage. In the open pore polyurethane foam... (Complete abstract click electronic access below) / Mestre