The diploma thesis deals with the possibility of using the addition of nanoparticles to improve the properties of cement composites. The theoretical part summarizes the findings of research in this area with a focus on methods of dispersion of nanoparticles and their treatment for use in cement composites. The experimental part focuses on the comparison of methods of dispersion and plasma treatment of reduced graphene oxide (rGO) nanoparticle solutions from the point of view of the agglomeration process. During this work, a method of systematic optical/visual monitoring of sedimentation/agglomeration was developed to complement sophisticated methods such as spectrophotometry (UV/Vis) and electron microscopy (SEM). Furthermore, the effect of the addition of rGO on the properties of cement mortar, in the form of aqueous solutions prepared by the dispersion methods determined in the previous section, was investigated.

Debido a la importancia de las estructuras marítimas se requiere que el concreto con el que se fabrican garantice su impermeabilidad frente a las aguas del mar, siendo los puertos los que sufren diferentes anomalías al estar en contacto directo con los sulfatos y cloruros, que lo degradan progresivamente ocasionando fisuración. Para ello se estudió la influencia de la adición de Nanotubos de Carbono (NTC) a las mezclas de concreto. Los NTC poseen una gran superficie específica que incide en la matriz de cemento modificando los silicatos de calcio hidratado, produciendo una mayor cohesión y el aumento de la compacidad del concreto. Para corroborar la efectividad de la adición de NTC las propiedades del concreto se elaboró 2 diseños de mezcla, uno con NTC-0% y otro diseño con adición de NTC (0.05%, 0.10% y 0.15%). Inicialmente se caracterizaron los materiales y se evaluó el proceso de dispersión de NTC en las mezclas de concreto utilizando superplastificante y haciendo uso de la sonicación como método de dispersión. Asimismo, se realizaron ensayos de asentamiento, de resistencia a la compresión, tracción, flexión y el ensayo de permeabilidad. El presente trabajo busca reducir la permeabilidad del concreto de las estructuras portuarias ubicados en zonas de salpicaduras y mareas, estudiando para ello diferentes propiedades físicas, mecánicas y la viabilidad económica del concreto con NTC; los resultados indican que el asentamiento disminuye, las resistencias a la compresión, tracción y flexión aumentan, la profundidad de penetración del agua disminuye, y el costo por m3 es mayor. / Due to the importance of maritime structures, it is required that the concrete with which they are manufactured guarantees its impermeability against the waters of the sea, being the ports those that suffer different anomalies when being in direct contact with sulfates and chlorides, which degrade it. progressively causing cracking. For this, the influence of the addition of Carbon Nanotubes (NTC) to concrete mixtures was studied. NTCs have a large specific surface that affects the cement matrix, modifying the hydrated calcium silicates, producing greater cohesion, and increasing the compactness of the concrete. To corroborate the effectiveness of the addition of NTC the properties of the concrete, 2 mix designs were elaborated, one with NTC-0% and another design with the addition of NTC (0.05%, 0.10% and 0.15%). Initially, the materials were characterized and the NTC dispersion process in concrete mixtures was evaluated using superplasticizer and using sonication as a dispersion method. Likewise, settlement tests, resistance to compression, traction, bending and the permeability test were carried out. This work seeks to reduce the permeability of concrete in port structures located in splash and tidal areas, studying different physical and mechanical properties and the economic viability of concrete with NTC; The results indicate that the settlement decreases, the resistance to compression, traction and bending increase, the depth of water penetration decreases, and the cost per m3 is greater. / Tesis

Für nanoskalige Füllpartikel, die stark zum Agglomerieren tendieren, ist das Ultraschalldispergieren mittels Sonotrode eine geeignete Methode, um Agglomerate hinreichend gut zu entbündeln. Um dabei die optimalen Ultraschallparameter ermitteln zu können, ist es nötig, das effektive Dispergiervolumen, in welchem die Agglomerate durch Kavitation aufgebrochen werden, zu kennen. Die hier vorgestellte CAD-basierte Methode zur Berechnung des effektiven Dispergiervolumens ist dabei deutlich weniger zeitintensiv als die bisher üblicherweise verwendete analytische Methode.

Eine effektive Strategie zur Verhinderung der Ausbreitung von Infektionskrankheiten in der Aquakultur ist die Anwendung geeigneter Präventionsmaßnahmen, insbesondere die Impfung von Fischen. Das effektivste Impfverfahren stellt die individuelle Injektion des Impfstoffes dar. Bei Milliarden von Fischen jährlich ist dies jedoch sehr zeit- und kostenintensiv. Bei Säugetieren gilt Niederfrequenz-Sonophorese (LFS) als eine der fortschrittlichsten Technologien zur transdermalen Verabreichung von Wirkstoffen. So entstand die Idee, bei Fischen die Aufnahme von Wirkstoffen während einer Tauchbadbehandlung mit Hilfe von LFS zu verbessern. Die vorliegende Arbeit zeigt, dass mit einer Beschallungsintensität von etwa 60 mW/cm^2 die Aufnahme eines Bakterienimpfstoffs in das Kiemengewebe von Regenbogenforellen um den Faktor 240 erhöht werden konnte. Bei dieser Intensität traten geringe oder keine Nebenwirkungen auf. Bei höheren Beschallungsintensitäten wurde eine noch höhere Aufnahme des Bakterienimpfstoffes, aber auch schädliche Nebenwirkungen beobachtet. Darüber hinaus zeigte LFS eine durch eine lokale Entzündungsreaktion und Aktivierung von T-Helferzellen in den Kiemen charakterisierte, Adjuvans-ähnliche Wirkung. Ein Impfversuch mit Koi Karpfen und einem inaktivierten Impfstoff gegen das Koi-Herpesvirus zeigte, dass LFS das Potential hat, den mit einer Tauchbadimpfung erzielbaren Immunschutz zu verbessern. LFS konnte auch für die Verabreichung anderer Substanzen wie Antibiotika verwendet und die Aufnahme von Oxytetracyclin um den Faktor fünf erhöht werden. Zusammenfassend lässt sich sagen, dass die Effektivität einer Tauchbadimpfung von Fischen mit LFS durch die gesteigerte Impfstoffaufnahme und dessen Adjuvans-ähnlichen Wirkung verbessert werden kann. Darüber hinaus könnte mithilfe LFS die therapeutische Dosis von Antibiotika bei Badbehandlungen verringert werden. Es erfordert jedoch noch weitere Studien, um diese Technologie aus dem Labor in die Praxis zu übertragen. / In aquaculture, the use of prevention methods, such as vaccination of fish, is an effective strategy to avoid infectious diseases. However, the most effective route of vaccination for fish is the one-by-one intraperitoneal injection, which that is very laborious and expensive to apply for billions of fish every year. Low Frequency Sonophoresis (LFS) has been recognized as one of the most advanced technologies in transdermal delivery of substances in mammals. Thus, it has been suggested to use LFS to enhance the uptake of substances in fish during bath treatments. The present study shows that a low sonication intensity of ca. 60 mW/cm^2 at 37 kHz increased the uptake of a bacterin into the gill tissue of rainbow trout by up to a factor of 240. At this intensity, no or only minimal side effects occurred. At higher sonication intensities, an even higher bacterin uptake but also deleterious side effects were observed. In addition, LFS showed an adjuvant-like effect characterized by a local inflammatory response and T-helper cell activation in the gills. A vaccination trial with koi carp and an inactivated vaccine against the Koi Herpes Virus (KHV) showed that LFS has the potential to enhance the immune protection achieved by immersion vaccination. In addition LFS can also be used for the administration of other substances, such as antibiotics, here we showed that the uptake of Oxytetracycline could be increased by factor five. In summary, the efficacy of the immersion vaccination of fish could be improved by low-frequency ultrasound due, to the increased vaccine uptake along with its adjuvant-like effect. Furthermore, LFS could also reduce the required therapeutic dose of antibiotics in bath treatments, making them more effective, cheaper and environmentally friendly. However, further practical studies will be required to transfer this technology from the lab to the field.

INTRODUÇÃO: O diagnóstico microbiológico das infecções em artroplastias é de fundamental importância para a definição da estratégia de uso dos antimicrobianos. As culturas microbiológicas convencionais apresentam elevados índices de falso-negativos, em especial, nas infecções crônicas, em que é frequente a presença do biofilme aderido ao implante. A utilização de amostras deste biofilme, viáveis à cultura, a partir de seu descolamento do implante pela técnica de sonicação, tem mostrado aumento da sensibilidade em publicações recentes. O objetivo deste estudo foi comparar os resultados das culturas microbiológicas de fragmentos de tecido periprotético, realizadas em meio sólido, àquelas obtidas pelo cultivo do líquido oriundo da sonicação do implante removido, semeado, inicialmente, em frascos de hemocultura e, posteriormente, em meio sólido. MÉTODOS: Neste estudo de análise descritiva, prospectivo e comparativo, 30 pacientes com diagnóstico de infecção em artroplastias de joelho ou quadril, com mais de 90 dias de história, tiveram seus implantes cirurgicamente removidos e foram coletadas seis amostras do tecido periprotético, de locais previamente determinados, para a realização de cultura microbiológica em meios sólidos. Simultaneamente, os implantes foram submetidos ao processo de sonicação e o material resultante foi injetado em frascos de hemocultura BD Bactec e submetidos ao processo de cultura automatizada. Todas as amostras foram pesquisadas quanto à presença de bactérias aeróbias, anaeróbias, micobactérias e fungos, e os resultados comparados por meio de análise estatística, em busca da superioridade de um método sobre o outro. Como objetivo secundário, buscou-se analisar quais os pontos de coleta do tecido periprotético teriam maior sensibilidade em suas culturas. RESULTADOS: Não houve diferenças estatisticamente significantes da amostra em relação ao gênero, patologia articular primária, tipo de artroplastia, localização do implante ou lateralidade. Em 17 casos (56,7%), houve uso de antimicrobianos no período de 15 dias que antecederam a retirada do implante. O método de cultura do fluido de sonicação mostrou sensibilidade de 86,7% e foi superior, de modo estatisticamente significante (P < 0,001), em relação à cultura dos fragmentos periprotéticos, cujos resultados tiveram sensibilidades entre 26,7 e 53,3%. O uso de antibioticoterapia recente não interferiu de modo estatisticamente significante na sensibilidade da cultura do líquido oriundo da sonicação. (P = 0,113). Quanto ao objetivo secundário, a coleta de fragmentos da membrana periprotética mostrou maior sensibilidade, estatisticamente significante, na comparação com três dos demais cinco pontos de coleta (P < 0,05). CONCLUSÕES: A cultura microbiológica do líquido obtido por sonicação dos implantes removidos de pacientes com diagnóstico de infecção periprotética e semeado inicialmente em frascos de hemocultura mostrou ter sensibilidade superior, estatisticamente significante, à cultura convencional de fragmentos do tecido periprotético semeados em meios sólidos. A cultura microbiológica da membrana periprotética mostrou ter maior sensibilidade em relação à maioria dos outros sítios que tiveram fragmentos de tecido periprotético pesquisados. / INTRODUCTION: Microbiological diagnosis in periprosthetic infection is of fundamental importance to define the most appropriate antimicrobial strategies. Conventional microbiological cultures have high rates of false negatives, especially in chronic infections, in which there is often the presence of biofilm attached to the implant. The use of samples of viable culturable biofilm taken from the detachment of the implant by sonication technique has been shown to increase the sensitivity in recent studies. The objective of this study was to compare the results of microbiological cultures of periprosthetic tissue fragments, made in a solid medium, to those obtained through the cultivation of the liquid coming from the sonication of the removed implant initially seeded in blood culture bottles and later in solid medium. METHODS: Using descriptive, prospective and comparative analysis, thirty patients with a diagnosis of infected knee or hip arthroplasty, with more than ninety days of history, had their implants surgically removed. Six periprosthetic tissue samples, collected at predetermined places, were used for microbiological culture on solid media. Simultaneously, the implants were subjected to the sonication process, and the resulting material was injected into vials of BD Bactec blood cultures and subjected to an automated culture process. All samples were screened for the presence of aerobic bacteria, anaerobes, mycobacteria and fungi and the results compared by statistical analysis to find the superiority of one method over the other. As a secondary objective, this study sought to analyze which of the periprosthetic tissue collecting points would have greater sensitivity in their cultures. RESULTS: There were no statistically significant differences in the sample as related to gender, primary joint pathology, type of arthroplasty, implant location or laterality. In seventeen cases (56.7%), antimicrobials were used within the 15-day period leading up to the removal of the implant. The sonication culture fluid showed a sensitivity of 86.7% and was higher, statistically significant (P < 0.001) in relation to the culture of periprosthetic fragments, where results displayed sensitivities between 26.7 and 53.3%. The use of recent antibiotic therapy did not affect the sensitivity of the liquid coming from the sonication culture, which was not statistically significant (P = 0.113). As for the secondary objective, the collection of periprosthetic membrane fragments showed higher sensitivity, statistically significant (P < 0.05), as compared to three of the remaining five collecting points. CONCLUSIONS: The microbiological culture liquid obtained by sonication of the implants removed from patients with diagnosis of periprosthetic infection and initially seeded in blood culture bottles was shown to have superior sensitivity, statistically significancy, as compared to conventional culture of the periprosthetic tissue fragments seeded on solid media. The microbiological culture of the periprosthetic membrane seems to be more sensitive compared to most other sites that had periprosthetic tissue fragments surveyed

This thesis reports the viability of E. coli cell extracts prepared using equipment that is both common to biotechnology laboratories and able to process small volume samples and expression of proteins containing unnatural amino acids (UAAs) at higher level using PCR amplified linear DNA templates (LETs) in cell-free protein synthesis (CFPS) system. E. coli-based cell extracts are a vital component of inexpensive and high-yielding CFPS reactions. However, effective preparation of E. coli cell extract is limited to high-pressure homogenizers (French press style or impinge-style) or bead mill homogenizers, which all require a significant capital investment. This work specifically assessed the following capital cost lysis techniques: (1) sonication, (2) bead vortex mixing, (3) freeze-thaw cycling, and (4) lysozyme incubation to prepare E. coli cell extract for CFPS. In this work, simple shake flask fermentation with a commercially available E. coli strain was used. Additionally, the RNA polymerase was over expressed in the E. coli cells prior to lysis which eliminated the need to add independently purified RNA polymerase to the CFPS reaction. As a result, high yielding E. coli-based cell extract was prepared using equipment requiring reduced capital investment and common to biotechnology laboratories. To our knowledge, this is the first successful prokaryote-based CFPS reaction to be carried out with extract prepared by sonication or bead vortex mixing. LETs are an attractive alternative to plasmids for site-specific incorporation of unnatural amino acids in proteins in the CFPS system because of their short preparation time and ease of production. However, major limitations associated with LETs are: (1) their degradation by RecBCD enzyme present in the cell-extract used for CFPS and (2) high CFPS energy costs. In this work, we report the optimization of LET-based CFPS for improved protein yield by inhibiting the RecBCD enzyme with small inhibitor molecules resulting in three fold increment in yield of protein containing UAA. We also assessed alternative energy sources such as glucose, fructose-1,6-bisphospate, creatine phosphate/creatine kinase, and high glutamate salt for cost reduction. This work could be important for high-throughput applications based on linear expression templates. This work demonstrates simple E. coli extract preparation and improved yield with linear expression templates for further advancements of cell-free protein synthesis system.

The excellent electrical and mechanical properties of carbon nanotubes (CNTs) provide interesting opportunities to realize new types of strain gauges. However, there are still challenges for the further development of CNT film strain gauges, for instance the lack of design rules, the homogeneity, stability and reproducibility of CNT films. This thesis aims to address these issues from two sides: simulation and experiment. Monte Carlo simulations show that both the sheet resistance and gauge factor of CNT films are determined essentially by the two-dimensional exclude area of CNTs. It was shown, for the first time, that the variation of the CNT film gauge factor follows the percolation scaling law. The sheet resistance and gauge factor both have a power-law divergence when approaching the percolation threshold. The standard deviation of film resistances, however, also increases correspondingly. These findings of simulations provide a general guide to the tailoring of material property of CNT films in strain sensing applications: a compromise should be made between the reproducibility, conductivity and sensitivity of CNT films depending on application purposes. From the experimental side, the processing parameters for the preparation of CNT dispersions were first investigated and optimized. The reproducibility of the film resistance is significantly improved by selecting a suitable sonication time. In strain measurements it was found that for most CNT films the film resistance responses nonlinearly to the applied strain. The dependence of the film resistance on the strain can be roughly divided into two regions with nearly linear behavior respectively. The gauge factor varies with the quality of CNTs and the depositing method. A gauge factor up to 8 was achieved in the high strain region. The nonlinear response behavior was found in simulations when the CNT waviness is properly taken into account. To achieve a high gauge factor and simultaneously retain the high conductivity and reproducibility, good-quality MWCNTs were integrated in polyethylene oxide (PEO). A high gauge factor up to 10 was achieved for the composite film with CNT weight fraction of 2.5%. The resistance and gauge factor can be tuned by changing the MWCNT weight fraction with respect to PEO. A careful comparison of simulation and experiment results show that a good qualitative agreement can be achieved between them in many respects.

INTRODUÇÃO: O diagnóstico microbiológico das infecções em artroplastias é de fundamental importância para a definição da estratégia de uso dos antimicrobianos. As culturas microbiológicas convencionais apresentam elevados índices de falso-negativos, em especial, nas infecções crônicas, em que é frequente a presença do biofilme aderido ao implante. A utilização de amostras deste biofilme, viáveis à cultura, a partir de seu descolamento do implante pela técnica de sonicação, tem mostrado aumento da sensibilidade em publicações recentes. O objetivo deste estudo foi comparar os resultados das culturas microbiológicas de fragmentos de tecido periprotético, realizadas em meio sólido, àquelas obtidas pelo cultivo do líquido oriundo da sonicação do implante removido, semeado, inicialmente, em frascos de hemocultura e, posteriormente, em meio sólido. MÉTODOS: Neste estudo de análise descritiva, prospectivo e comparativo, 30 pacientes com diagnóstico de infecção em artroplastias de joelho ou quadril, com mais de 90 dias de história, tiveram seus implantes cirurgicamente removidos e foram coletadas seis amostras do tecido periprotético, de locais previamente determinados, para a realização de cultura microbiológica em meios sólidos. Simultaneamente, os implantes foram submetidos ao processo de sonicação e o material resultante foi injetado em frascos de hemocultura BD Bactec e submetidos ao processo de cultura automatizada. Todas as amostras foram pesquisadas quanto à presença de bactérias aeróbias, anaeróbias, micobactérias e fungos, e os resultados comparados por meio de análise estatística, em busca da superioridade de um método sobre o outro. Como objetivo secundário, buscou-se analisar quais os pontos de coleta do tecido periprotético teriam maior sensibilidade em suas culturas. RESULTADOS: Não houve diferenças estatisticamente significantes da amostra em relação ao gênero, patologia articular primária, tipo de artroplastia, localização do implante ou lateralidade. Em 17 casos (56,7%), houve uso de antimicrobianos no período de 15 dias que antecederam a retirada do implante. O método de cultura do fluido de sonicação mostrou sensibilidade de 86,7% e foi superior, de modo estatisticamente significante (P < 0,001), em relação à cultura dos fragmentos periprotéticos, cujos resultados tiveram sensibilidades entre 26,7 e 53,3%. O uso de antibioticoterapia recente não interferiu de modo estatisticamente significante na sensibilidade da cultura do líquido oriundo da sonicação. (P = 0,113). Quanto ao objetivo secundário, a coleta de fragmentos da membrana periprotética mostrou maior sensibilidade, estatisticamente significante, na comparação com três dos demais cinco pontos de coleta (P < 0,05). CONCLUSÕES: A cultura microbiológica do líquido obtido por sonicação dos implantes removidos de pacientes com diagnóstico de infecção periprotética e semeado inicialmente em frascos de hemocultura mostrou ter sensibilidade superior, estatisticamente significante, à cultura convencional de fragmentos do tecido periprotético semeados em meios sólidos. A cultura microbiológica da membrana periprotética mostrou ter maior sensibilidade em relação à maioria dos outros sítios que tiveram fragmentos de tecido periprotético pesquisados. / INTRODUCTION: Microbiological diagnosis in periprosthetic infection is of fundamental importance to define the most appropriate antimicrobial strategies. Conventional microbiological cultures have high rates of false negatives, especially in chronic infections, in which there is often the presence of biofilm attached to the implant. The use of samples of viable culturable biofilm taken from the detachment of the implant by sonication technique has been shown to increase the sensitivity in recent studies. The objective of this study was to compare the results of microbiological cultures of periprosthetic tissue fragments, made in a solid medium, to those obtained through the cultivation of the liquid coming from the sonication of the removed implant initially seeded in blood culture bottles and later in solid medium. METHODS: Using descriptive, prospective and comparative analysis, thirty patients with a diagnosis of infected knee or hip arthroplasty, with more than ninety days of history, had their implants surgically removed. Six periprosthetic tissue samples, collected at predetermined places, were used for microbiological culture on solid media. Simultaneously, the implants were subjected to the sonication process, and the resulting material was injected into vials of BD Bactec blood cultures and subjected to an automated culture process. All samples were screened for the presence of aerobic bacteria, anaerobes, mycobacteria and fungi and the results compared by statistical analysis to find the superiority of one method over the other. As a secondary objective, this study sought to analyze which of the periprosthetic tissue collecting points would have greater sensitivity in their cultures. RESULTS: There were no statistically significant differences in the sample as related to gender, primary joint pathology, type of arthroplasty, implant location or laterality. In seventeen cases (56.7%), antimicrobials were used within the 15-day period leading up to the removal of the implant. The sonication culture fluid showed a sensitivity of 86.7% and was higher, statistically significant (P < 0.001) in relation to the culture of periprosthetic fragments, where results displayed sensitivities between 26.7 and 53.3%. The use of recent antibiotic therapy did not affect the sensitivity of the liquid coming from the sonication culture, which was not statistically significant (P = 0.113). As for the secondary objective, the collection of periprosthetic membrane fragments showed higher sensitivity, statistically significant (P < 0.05), as compared to three of the remaining five collecting points. CONCLUSIONS: The microbiological culture liquid obtained by sonication of the implants removed from patients with diagnosis of periprosthetic infection and initially seeded in blood culture bottles was shown to have superior sensitivity, statistically significancy, as compared to conventional culture of the periprosthetic tissue fragments seeded on solid media. The microbiological culture of the periprosthetic membrane seems to be more sensitive compared to most other sites that had periprosthetic tissue fragments surveyed

The excellent electrical and mechanical properties of carbon nanotubes (CNTs) provide interesting opportunities to realize new types of strain gauges. However, there are still challenges for the further development of CNT film strain gauges, for instance the lack of design rules, the homogeneity, stability and reproducibility of CNT films. This thesis aims to address these issues from two sides: simulation and experiment. Monte Carlo simulations show that both the sheet resistance and gauge factor of CNT films are determined essentially by the two-dimensional exclude area of CNTs. It was shown, for the first time, that the variation of the CNT film gauge factor follows the percolation scaling law. The sheet resistance and gauge factor both have a power-law divergence when approaching the percolation threshold. The standard deviation of film resistances, however, also increases correspondingly. These findings of simulations provide a general guide to the tailoring of material property of CNT films in strain sensing applications: a compromise should be made between the reproducibility, conductivity and sensitivity of CNT films depending on application purposes. From the experimental side, the processing parameters for the preparation of CNT dispersions were first investigated and optimized. The reproducibility of the film resistance is significantly improved by selecting a suitable sonication time. In strain measurements it was found that for most CNT films the film resistance responses nonlinearly to the applied strain. The dependence of the film resistance on the strain can be roughly divided into two regions with nearly linear behavior respectively. The gauge factor varies with the quality of CNTs and the depositing method. A gauge factor up to 8 was achieved in the high strain region. The nonlinear response behavior was found in simulations when the CNT waviness is properly taken into account. To achieve a high gauge factor and simultaneously retain the high conductivity and reproducibility, good-quality MWCNTs were integrated in polyethylene oxide (PEO). A high gauge factor up to 10 was achieved for the composite film with CNT weight fraction of 2.5%. The resistance and gauge factor can be tuned by changing the MWCNT weight fraction with respect to PEO. A careful comparison of simulation and experiment results show that a good qualitative agreement can be achieved between them in many respects.

The disposal of waste from agricultural activities has been recognised as a source of environmental contamination by endocrine disrupting chemicals (EDCs). The New Zealand dairy industry produces a large volume of dairy farm effluent, which contains EDCs in the form of estrogens. Most of this dairy farm effluent is applied onto the land for disposal. Groundwater and soil contamination by estrogens following waste application on the land have been reported overseas, but our understanding of the processes and factors governing the fate of estrogens in the soil is poor. Therefore the main goal of the present study was to better understand the fate and transport of estrogens, in particular 17β-estradiol (E2) and estrone (E1) in soil. In order to quantify E1 and E2 in drainage water and soil samples, chemical analysis by gas-chromatography mass-spectrometry (GC-MS) was carried out. This included sample extraction, sample clean-up through silica gel and gel permeation chromatography, and sample extract derivatisation prior to analysis. In order to develop a reliable method to extract estrogens from soil, research was conducted to optimise E1 and E2 extraction conditions by adjusting the number of sonication and shaking events, as well as the volume and type of solvent. Among five solvents and solvent mixtures tested, the best recovery on spiked and aged soil was obtained using an isopropanol/water (1:1) mix. A microcosm experiment was carried out to determine the dissipation rates of E2 and E1, at 8°C and at field capacity, in the Templeton soil sampled at two different depths (5-10 cm and 30-35 cm). The dissipation rates decreased with time and half-life values of 0.6-0.8 d for E1 and 0.3-0.4 d for E2 were found for the two depths studied. A field transport experiment was also carried out in winter, over three months, by applying dairy farm effluent spiked with estrogens onto undisturbed Templeton soil lysimeters (50 cm in diameter and 70 cm deep). The hormones were applied in dairy farm effluent at 120 mg m⁻² for E2 and 137 mg m⁻² for E1. The results of the transport experiment showed that in the presence of preferential/macropore flow pathways 0.3-0.7% of E2 and 8-13% of E1 was recovered in the leachate at the bottom of the lysimeters after 3 months, and 1-7% of the recovered E2 and 3-54% of the recovered E1 was leached within 2 days of application. These results suggest that leaching of estrogens via preferential/macropore flow pathways is the greatest concern for groundwater contamination. In the absence of preferential/macropore flow pathways, a significant amount (> 99.94%) of both hormones dissipated in the top 70 cm of soil, due to sorption and rapid biodegradation. Surprisingly, in all cases, estrogen breakthrough occurred before that of an inert tracer (bromide). This could not be explained by the advection-dispersion transport of estrogens, nor by their presence as antecedent concentrations in the soil. It was therefore suggested that colloidal enhanced transport of estrogens was responsible for the earlier breakthrough of estrogens and caused the leaching of a fraction of the applied estrogens to a soil depth of 70 cm. A two-phase model, adapted from a state-space mixing cell model, was built to describe the observed estrogen transport processes under transient flow. The model takes into account 3 transport processes namely, advection-dispersion, preferential/macropore flow and colloidal enhanced transport. This model was able to successfully describe the estrogen transport observed from the lysimeters.