Traditional assessments of contaminated sites require the collection and analysis of field media. Specifically, sediment analysis is used to determine type of contaminant as well as total contaminant concentrations (TCC). Although TCC can be used to determine if a site is contaminated, it is unable to adequately predict exposure and bioaccumulation in organisms. Biota-sediment accumulation factors were originally introduced to calculate and predict expected exposure to organisms based on sediment TCC. As they have been shown to be unreliable with field sediments, their use is limited. Alternatively, Tenax has been examined as a tool for measuring exposure to hydrophobic organic contaminants, where the Tenax extractable concentration is related to the bioaccumulated organism concentration. Although this relationship has been demonstrated in multiple studies, few have actually related the data from multiple sites to develop a standard model of Tenax accumulation. This research had two specific goals: Develop a literature based model of Tenax accumulation of polychlorinated biphenyl congeners (PCBs) and test it's applicability to field collected sediments from the Ottawa River (OR, Toledo OH, Chapter 2) and verify the use of the model in a highly-disturbed, post-dredge system, as well as the use of Tenax as an indicator of changes in bioavailability after dredging (Chapter 3). The literature-based complete Tenax model (TM) provided a strong model for the prediction of bioaccumulation in Lumbriculus variegatus (r2=0.91). When compared to the pre-dredge data from the OR, 95% of the data were encompassed by the CTM. No bias of the model was observed across homologue groups. Subsequently, the model was used with sediments collected after remediation via dredging from the OR. In this study, the CTM encompassed 73% of the data. Although all sites along the river were considered disturbed by the dredging, resuspension, and drift of sediments, data from sites that were less disturbed were better described by the model (86% versus 64% of dredged data). Overall, the CTM is recommended for use in the prediction of exposure and accumulation of PCBs in field sediments.

No description available.

No description available.

Bifenilas Policloradas (PCB) são compostos orgânicos clorados altamente tóxicos e também são considerados poluentes orgânicos persistentes. Sua alta estabilidade térmica e química é responsável pela sua difícil degradação, e quando estas substâncias são liberadas no meio ambiente, sua acumulação nos ecossistemas incorpora-se na cadeia alimentar, exibindo biomagnificação. Deve-se ressaltar a importância para o meio ambiente do tratamento de resíduos com PCB. Considerando que a Convenção de Estocolmo sobre poluentes orgânicos persistentes (POP) estabeleceu a eliminação do uso de PCB em equipamentos, por exemplo, transformadores e capacitores elétricos, até 2025. O objetivo deste trabalho foi estudar a remoção de PCB pelos processos de extração usando fluido supercrítico e a extração convencional (Soxhlet) no tratamento de materiais contaminados com PCB. Assim foi desenvolvida uma ferramenta computacional para correlacionar os dados de solubilidade de PCB em CO₂ supercrítico, usando a equação de estado de Peng-Robinson com parâmetros ajustados. O procedimento de cálculo foi inicialmente usado para uma série de compostos aromáticos (naftaleno, antraceno, fenantreno e bifenil), a fim de testar a abordagem. Os parâmetros binários para a regra de mistura quadrática clássica (vdW2) foram sistematicamente estimados, juntamente com um novo conjunto de dados de pressão de vapor, a fim de descrever a dependência da temperatura e alcançar incertezas experimentais. Finalmente, foram utilizados os parâmetros estimados para simular valores de solubilidade dos principais congêneres constituintes das misturas comerciais reais de PCB, como função das condições de operação de extração com uma solução simultânea das equações de equilíbrio para cada composto. A modelagem termodinâmica demonstrou ser viável para a análise de processos. / Polychlorinated Biphenyls (PCB) are chlorinated organic compounds which are highly toxic and are also considered persistent organic pollutants. The high thermal and chemical stability of PCB are responsible for their hard degradation, and when these substances are liberated in the environment, their accumulation in ecosystems leads to their incorporation in the food chain, exhibiting biomagnification. It should be emphasized the environmental importance for treating wastes with PCB. Considering that, Stockholm Convention on persistent organic pollutants (POP) established the elimination of the use of PCB in equipments, e.g. electrical transformers and capacitors, by 2025. The objective of this work was to study the removal of PCB by the processes of extractions using supercritical fluid and conventional (Soxhlet) extraction method in the treatment of contaminated materials with PCB. As well was the formulation of a computational tool to correlate solubility data of PCB in supercritical CO₂, using Peng-Robinson equation of state with fitted parameters. The calculation procedure was initially used for a series of aromatic compounds (naphthalene, anthracene, phenanthrene and biphenyl) in order to test the approach. The binary parameters for the classical quadratic mixing rule (vdW2) were systematically estimated, together with a new set of vapor pressure in order to describe the temperature dependence and achieve experimental uncertainties. Finally, the estimated parameters were used to simulate solubility values of the major constituent congeners of commercial and real mixtures of PCB, as function of the operational conditions of extraction by a simultaneous solution of the equilibrium equations for each compound. The thermodynamic modeling demonstrated to be feasible for process analysis and design.

Polychlorinated biphenyls (PCBs) are carcinogenic, persistent, and bioaccumulative contaminants that pose risks to human and environmental health. PCB biodegradation by indigenous microbial communities could be a cost-effective and an environmental-friendly bioremediation strategy for in situ PCB removal. A comprehensive understanding of the microbial PCB degradation at the contaminated site is required for the acceptance and optimization of using microbial PCB degradation as the site clean-up strategy. This thesis describes investigations of the aerobic and anaerobic microbial degradation of PCBs under both field and laboratory conditions. The microbial PCB degradation potential in sediments from Indiana Harbor and Ship Canal (IHSC), a site that was historically contaminated by PCBs, was explored by analyzing the PCB congener distributions and microbial communities in two core sediment samples. PCB congener analysis suggested the possibility of in situ dechlorination in deep sediments. Molecular analysis of biomarker genes revealed the potential of both aerobic and anaerobic PCB degradation in sediments. Microbial communities were characterized by the combination use of terminal restriction fragment length polymorphism (T-RFLP), clone library, and pyrosequencing. These methods elucidated the dominant role of Proteobacteria, especially Acidovorax and Acinetobacter in sediments. To improve the microbial PCB degradation, phytoremediation with switchgrass (Panicum vigratum) was employed under laboratory conditions. Congener analysis showed that both phytoextraction and microbial PCB degradation contributed to the enhanced PCB removal in the presence of switchgrass. Bioaugmentation with Burkholderia xenovorans LB400 was performed to further promote aerobic PCB degradation. The presence of LB400 was associated with improved degradation of PCB 52, but not PCB77 or PCB 153. Increased abundance of the biphenyl dioxygenase gene, which is indicative of aerobic PCB degradation, and its transcript were observed after bioaugmentation, suggesting active aerobic PCB degradation. To promote the anaerobic PCB degradation, redox cycling (alternating flooding and non-flooding) was performed. Redox cycling was found to improve the removal of PCB 153 in unplanted soils and to increase the dechlorinating Chloroflexi population. Characterization of the microbial community by T-RFLP and clone library revealed that Proteobacteria and Acidobacteria were dominant. Species that contain dechlorination potential were identified, including Geobacter and Clostridium, suggesting that their possible role in PCB dechlorination. The research described in this thesis provides scientific knowledge and evidence for the feasibility of employing bioremediation including natural attenuation, phytoremediation, and bioaugmentation to clean up PCB contamination. Such information will be critical in selecting and optimizing remediation strategies for PCB contaminated sites.

<p>Polychlorinated biphenyls, PCBs, were used in elastic sealants in buildings during the years1956-1973. Studies of PCB have revealed that it is harmful for humans and animals,especially water-living predators and other top-predators. It is also a persistent organicpollutant and remains in the environment for a very long time. To reduce the levels of PCB inthe environment, it has to be removed from the buildings. According to Swedish law, theproperty holder has to decontaminate sealants with a PCB level of 500 mg/kg or above. Themunicipalities are the supervising authority and they shall follow up the decontaminations toassure that the PCB has been properly removed from the buildings. The PCBdecontaminationin Eskilstuna municipality has not been a prioritised work, hence, there isPCB left in the buildings which need to be removed. To facilitate the decontamination-work,a plan of action has been developed. This plan will assist the inspector in prioritising thedifferent cases.</p>

Polychlorinated biphenyls, PCBs, were used in elastic sealants in buildings during the years1956-1973. Studies of PCB have revealed that it is harmful for humans and animals,especially water-living predators and other top-predators. It is also a persistent organicpollutant and remains in the environment for a very long time. To reduce the levels of PCB inthe environment, it has to be removed from the buildings. According to Swedish law, theproperty holder has to decontaminate sealants with a PCB level of 500 mg/kg or above. Themunicipalities are the supervising authority and they shall follow up the decontaminations toassure that the PCB has been properly removed from the buildings. The PCBdecontaminationin Eskilstuna municipality has not been a prioritised work, hence, there isPCB left in the buildings which need to be removed. To facilitate the decontamination-work,a plan of action has been developed. This plan will assist the inspector in prioritising thedifferent cases.

Polychlorinated biphenyls (PCBs) are carcinogenic persistent contaminants. Although their manufacturing in North America ceased in the late 1970s, their high heat resistance made their use widespread over their production lifetime. As a result, PCB contamination has occurred globally and in particular has plague brownfield redevelopment in urban environments. The remediation of PCB contaminated soil or sediments has historically been dealt with through the expensive and unsustainable practice of excavation followed by off-site disposal or incineration. One potential technology that has shown some success with on-site remediation of PCB contamination is solvent extraction. Solvent extraction is technically simple; it involves excavating the contaminated soil, placing it in a vessel and adding solvent. The PCBs are extracted by the solvent and the treated soil is returned for use on site. Although successful at removing a large quantity of PCBs from some soils, this technology can be improved upon by extracting additional PCB mass and making the extraction more efficient and suitable for colder climates. This thesis aimed to identify the factors controlling PCB extraction with solvents in order to optimize PCB extraction as it is applied on different soil types and in various climates. The research investigated the impact of elevated moisture contents (≤ 20% by weight) on solvent extraction efficiency, the effects of low temperatures (<5ºC) on solvent extraction, and developed a kinetic model to represent PCB solvent extraction. As past research has shown, weathered PCB in soil is more difficult to remove. Contaminated field samples from Southern Ontario, Canada were used for this work, rather than synthetically prepared samples. The impact of elevated moisture contents and low temperature on extraction efficiency was determined through a series of screening experiments using polar and non-polar solvents at both 20ºC and 4ºC. It was hypothesized that improved extractions may be possible with combinations of polar and non-polar solvents. Based on the results of these screening experiments, a factorial experiment was designed using solvent combinations to further assess the role of moisture contents and low temperatures. The role of PCB mass distribution among grain sizes was also evaluated to see if optimization based on grain size separation is possible. Finally, experiments were performed to generate data suitable for the development of a kinetic model that incorporates key factors affecting solvent extraction. Four suitable solvents for solvent extraction in Ontario were identified through a literature review and these were used for this work: isopropyl alcohol (polar), ethanol (polar), triethylamine (non-polar) and isooctane (non-polar). Triethylamine outperformed isooctane and performed best on its own rather than in combination with polar solvents. An interaction between soil moisture content and choice of polar solvent (isopropyl alcohol versus ethanol) was established: a given polar solvent achieves optimal PCB extraction at a specific moisture content range. Temperature was also identified as significantly influencing PCB extraction. Although it was determined that PCBs were distributed unevenly amongst grain sizes, a simple relationship between grain size and fractional organic carbon or organic content was not found. A simple two-compartment kinetic model was developed which is suitable for predicting the PCB concentrations extracted up to 24 hours. The model incorporates both temperature and soil to solvent ratio in order to estimate PCB concentration extracted.

Polychlorinated biphenyls (PCBs) are carcinogenic persistent contaminants. Although their manufacturing in North America ceased in the late 1970s, their high heat resistance made their use widespread over their production lifetime. As a result, PCB contamination has occurred globally and in particular has plague brownfield redevelopment in urban environments. The remediation of PCB contaminated soil or sediments has historically been dealt with through the expensive and unsustainable practice of excavation followed by off-site disposal or incineration. One potential technology that has shown some success with on-site remediation of PCB contamination is solvent extraction. Solvent extraction is technically simple; it involves excavating the contaminated soil, placing it in a vessel and adding solvent. The PCBs are extracted by the solvent and the treated soil is returned for use on site. Although successful at removing a large quantity of PCBs from some soils, this technology can be improved upon by extracting additional PCB mass and making the extraction more efficient and suitable for colder climates. This thesis aimed to identify the factors controlling PCB extraction with solvents in order to optimize PCB extraction as it is applied on different soil types and in various climates. The research investigated the impact of elevated moisture contents (≤ 20% by weight) on solvent extraction efficiency, the effects of low temperatures (<5ºC) on solvent extraction, and developed a kinetic model to represent PCB solvent extraction. As past research has shown, weathered PCB in soil is more difficult to remove. Contaminated field samples from Southern Ontario, Canada were used for this work, rather than synthetically prepared samples. The impact of elevated moisture contents and low temperature on extraction efficiency was determined through a series of screening experiments using polar and non-polar solvents at both 20ºC and 4ºC. It was hypothesized that improved extractions may be possible with combinations of polar and non-polar solvents. Based on the results of these screening experiments, a factorial experiment was designed using solvent combinations to further assess the role of moisture contents and low temperatures. The role of PCB mass distribution among grain sizes was also evaluated to see if optimization based on grain size separation is possible. Finally, experiments were performed to generate data suitable for the development of a kinetic model that incorporates key factors affecting solvent extraction. Four suitable solvents for solvent extraction in Ontario were identified through a literature review and these were used for this work: isopropyl alcohol (polar), ethanol (polar), triethylamine (non-polar) and isooctane (non-polar). Triethylamine outperformed isooctane and performed best on its own rather than in combination with polar solvents. An interaction between soil moisture content and choice of polar solvent (isopropyl alcohol versus ethanol) was established: a given polar solvent achieves optimal PCB extraction at a specific moisture content range. Temperature was also identified as significantly influencing PCB extraction. Although it was determined that PCBs were distributed unevenly amongst grain sizes, a simple relationship between grain size and fractional organic carbon or organic content was not found. A simple two-compartment kinetic model was developed which is suitable for predicting the PCB concentrations extracted up to 24 hours. The model incorporates both temperature and soil to solvent ratio in order to estimate PCB concentration extracted.

Cardiovascular disease remains the leading cause of death in Western societies. Endothelial dysfunction is one of the initiating steps in the development of atherosclerosis. While there is a strong correlation with a person’s genetics, lifestyle factors including smoking, physical activity, and diet can significantly increase a person’s susceptibility to the development of atherosclerosis. In addition to these lifestyle factors, there is a strong body of evidence linking exposure to environmental pollutants including persistent organic pollutants such as polychlorinated biphenyls to increased cardiovascular disease and mortality. It has been well-established that exercise protects against cardiovascular disease, but whether exercise can modulate PCB-induced cardiovascular inflammation and dysfunction is unknown. To investigate the effects of exercise on PCB-induced cardiovascular disease, two murine models of atherosclerosis, the ApoE-/- and the LDLr-/- mouse were utilized. Risk factors for cardiovascular disease including adiposity, glucose intolerance, hyperlipidemia, hypertension, oxidative stress, and inflammation, were assessed in these two models as well as mean atherosclerotic lesion size. Exercise positively modulates several risk factors associated with cardiovascular disease including hypertension, hyperlipidemia, adiposity and obesity, systemic levels of oxidative stress, inflammation, and glucose tolerance. Exercise significantly reduced mean lesion size in vehicle-treated animals. To assess the mechanism of protection of exercise in chapter 4, vascular reactivity studies were performed to measure endothelial function after exposure to PCB 77. Exercise prevented PCB-impaired endothelial function implicating the role of superoxide as a cause of impairment. Exercise upregulated phase II antioxidant enzymes. The work in this dissertation demonstrates several protective properties of exercise against PCB-induced cardiovascular disease; however, additional studies are needed to determine if exercise enhances metabolism and excretion of these environmental pollutants.