An increase in nanotechnology has seen an associated rise in nanoparticles released into the environment. Their potential toxicity and exposure to humans and the environment, the field of nanoecotoxicology, is not yet well understood. The interactions at the nanoparticle surface will play a fundamental role in the nanoparticle behaviour once released into the environment. This study aims to characterise the particle surface interaction, determining key parameters influential in the nanoparticle fate. Evanescent Wave Cavity Ring Down Spectroscopy techniques have been applied to study molecular interactions at the silica-water charged interface. The adsorption of the electronic spectrum of Crystal Violet has demonstrated the formation of a monolayer with different binding site orientation at the interface. The binding affinity for the chromophore was calculated as 29.15 ± 0.02 kJmol-1 at pH 9 and this was compared with other interface structures involving both inorganic and organic components. The study of the model interface was extended to the properties of CeO2 nanoparticles, where the surface charge density was determined to be 1.6 ± 0.3 e- nm-2.The nanoparticle surface charge controls the suspension stability which was measured for CeO2 nanoparticles giving a stability half-life of 330 ± 60 hours in pure water, and 3.6 ± 0.6 hours in ISOFish water. Studies were extended to the toxicity of ZnO nanoparticles. An assay was developed to quantify the photo-electron production for nanoparticles exposed to UV light both in deionised water and soil suspensions with a photo-radical production yield of 19 ± 2 % and an electron production of 709 e-s-1np-1 for a 100 mgL-1 suspension. The species-specific photo-radical assay was subsequently used to determine the rate of ZnO nanoparticle dissolution in water and soil suspensions. Comparable dissolution rates in complex cell growth media were also measured, detecting total zinc by Inductively Coupled Plasma Atomic Emission Spectroscopy, with comparable dissolution rates derived.

<p>Single-walled carbon nanotubes (SWNT) are highly ordered filamentous nanocarbon structures. As their commercial and industrial use becomes more widespread, it is anticipated that SWNT will enter the environment through waste streams and product degradation. Because of their highly hydrophobic nature, SWNT aggregate and settle out of aqueous environments, especially in saline environments such as estuaries. Therefore, sediments are a likely environmental sink for SWNT once released. It is important to understand how these materials will impact benthic estuarine systems since they are the probable target area for SWNT exposure in addition to containing many lower trophic level organisms whose survvial and contaminant body burdens can have a large impact on the overall ecosystem. Disruptions in lower trophic level organism survival can have negative consequences for higher trophic levels, impacting the overall health of the ecosystem. It is also important to consider contaminant bioaccumulation, trophic transfer and biomagnification. If SWNT are taken up by benthic invertebrates, there is the possibility for trophic transfer, increasing the exposure of SWNT to higher trophic level organisms that otherwise would not have been exposed. If this type of transfer occurs in environmentally important species, the potential for human exposure may increase. My research aims to determine the magnitude of the toxicity and bioaccumulation of SWNT in benthic estuarine systems, as well as determine how they interact with other contaminants in the environment. This research will contribute to the knowledge base necessary for performing environmental risk assessments by providing information on the effects of SWNT to benthic estuarine systems. </p><p> Before investigating the environmental effects of SWNT, it is imperative that a measurement method is established to detect and quantify SWNT once they enter the environment. This research utilized pristine, semiconducting SWNT to develop extraction and measurement methods to detect and quantify these specific materials in environmental media using near infrared fluorescence (NIRF) spectroscopy. Semiconducting SWNT fluoresce in the near infrared (NIR) spectrum when excited with visible&ndashNIR light. This unique optical property can be used to selectively measure SWNT in complex media. </p><p> The fate, bioavailability, bioaccumulation and toxicity of SWNT have not been extensively studied to date. Pristine SWNT are highly hydrophobic and have been shown to strongly associate with natural particulate matter in aquatic environments. In light of this, I have focused my research to examine the influence of sediment and food exposure routes on bioavailability, bioaccumulation, and toxicity of structurally diverse SWNT in several ecologically-important marine invertebrate species. No significant mortality was observed in any organism at concentrations up to 1000 mg/kg. Evidence of biouptake after ingestion was observed for pristine semiconducting SWNT using NIRF spectroscopy and for oxidized <super>14</super>C&ndashSWNT using liquid scintillation counting. After a 24 hour depuration period, the pristine semiconducting SWNT were eliminated from organisms to below the method detection limit (5 &mug/mL), and the <super>14</super>C&ndashSWNT body burden was decreased by an order of magnitude to a bioaccumulation factor (BAF) of <0.01. Neither pristine SWNT nor oxidized <super>14</super>C&ndashSWNT caused environmentally relevant toxicity or bioaccumulation in benthic invertebrates. Overall, the SWNT were not bioavailable and appear to associate with the sediment.</p><p> In addition to investigating the toxicity and bioaccumulation of SWNT as an independent toxicant, it is important to consider how they will interact with other contaminants in the environment (i.e., increase or decrease toxicity and bioaccumulation of co&ndashcontaminants, alter the environmental transport of co&ndashcontaminants, induce degradation of co&ndashcontaminants, etc.). I wanted to investigate the effects of SWNT on a complex mixture of contaminants already present in a natural system. New Bedford Harbor (NBH) sediment, which is contaminated with polychlorinated biphenyls (PCBs), was amended with pristine SWNT to determine if the presence of SWNT would mitigate the toxicity and bioaccumulation of the PCBs in deposit-feeding invertebrates. A dilution series of the NBH sediment was created using uncontaminated Long Island Sound (LIS) sediment to test 25% NBH sediment, 50% NBH sediment, 75% NBH sediment, and 100% NBH sediment. The results of this work showed increased organism survival and decreased bioaccumulation of PCBs in treatments amended with SWNT, with the greatest reduction observed in the 25% NBH sediment treatment group amended with 10 mg SWNT/g dry sediment. Polyethylene (PE) passive samplers indicated a reduction of interstitial water (ITW) PCB concentration of greater than 90% in the 25% NBH sediment + 10 mg SWNT/g dry sediment amendment. The ITW concentration was reduced because PCBs were not desorbing from the SWNT. Lower bioavailability leads to reduced potential for toxic effects, supporting the observation of increased survival and decreased bioaccumulation. Once in the sediment, not only are SWNT not bioavailable, they act as a highly sorptive phase, such as black carbon (BC), into which hydrophobic organic contaminants (HOCs), such as PCBS and polycyclic aromatic hydrocarbons (PAHs), can partition, thereby reducing the toxicity and bioavailability of co-occurring HOCs.</p><p> To more fully understand the impact of SWNT in this environment, their biodegradability also needs to be investigated. Biodegradation of SWNT could lead to release and/or transformation of sorbed HOCs as well as a change in the inherent transport, toxicity, and bioaccumulation of SWNT in the estuarine environment. Because the persistence of SWNT will be a primary determinant of the fate of these materials in the environment, I conducted experiments to determine if the fungus <italic>Trametes versicolor</italic>, the natural bacterial communities present in NBH sediment, and municipal wastewater treatment plant sludge could degrade or mineralize oxidized <super>14</super>C&ndashSWNT. Over a six month time period, no significant degradation or mineralization was observed. In all treatments, approximately 99% of the 14C-SWNT remained associated with the solid phase, with only approximately 0.8% of added <super>14</super>C present as dissolved species and only 0.1% present as <super>14</super>CO₂. These small pools of non-SWNT <super>14</super>C were likely due to trace impurities, as no differences in production were observed between treatments and abiotic (killed) controls.</p> / Dissertation

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-01-22T14:30:44Z No. of bitstreams: 1 hudsoncaetanopolonini.pdf: 5158429 bytes, checksum: e80426644833041649bdb5efa0029dcc (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-01-25T18:54:38Z (GMT) No. of bitstreams: 1 hudsoncaetanopolonini.pdf: 5158429 bytes, checksum: e80426644833041649bdb5efa0029dcc (MD5) / Made available in DSpace on 2016-01-25T18:54:38Z (GMT). No. of bitstreams: 1 hudsoncaetanopolonini.pdf: 5158429 bytes, checksum: e80426644833041649bdb5efa0029dcc (MD5) Previous issue date: 2014-04-16 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / No capítulo primeiro, objetivou-se avaliar o desempenho de permeação do veículo transdérmico magistral Pentravan para sistemas de distribuição transdérmica contendo Progesterona (P), Estradiol (E2) e Estriol (E3), isoladamente ou em associação de E2 + E3 (Biest). Um modelo experimental de pele humana feminina excisada foi utilizado para prever a permeação e a retenção das substâncias ativas em todas as camadas da pele. Além disso, o processo de fabricação para as formulações foi avaliado quanto à uniformidade de conteúdo das emulsões. Os métodos analíticos eco-friendly desenvolvidos para quantificação de hormônios sexuais femininos em emulsões transdérmicas foram adequados aos objetivos, o que foi comprovado através da validação dos mesmos. A avaliação do processo de manipulação das emulsões revelou que as embalagens à vácuo atualmente utilizadas por farmácias magistrais foram adequadas ao uso, e a utilização de moinho de rolos desempenhou papel fundamental na uniformidade de conteúdo de Eemuls e Biest. As taxas de liberação in vitro dos fármacos a partir de suas formulações foram adequadamente altas, e todas as formulações seguiram cinética de pseudo-primeira ordem, típica de produtos semissólidos. O estudo de permeação ex vivo demonstrou que todos as formulações foram capazes de promover a absorção transdérmica dos hormônios em quantidades comparáveis às praticadas atualmente por produtos industrializados. No capítulo segundo, duas partículas de titanato de bário (BT), da ordem micrométrica e manométrica, foram avaliadas quanto ao seu impacto em ambientes aquáticos. Uma caracterização dos materiais foi realizada. A seguir, utilizou-se duas algas (Chlorella vulgaris e Euglena gracilis) e uma cianobactéria (Anabaena flos-aquae) como organismos-modelo para avaliação da toxicidade. Tanto BT MP (micropartícula) quanto BT NP (nanopartícula) se mostraram carregadas negativamente, facilmente agregáveis, com uma taxa de liberação de íons Ba2+ para os meios de cultura que não ultrapassa 1,5%. BT mostrou um efeito tóxico estatisticamente significativo (p<0,05) no crescimento e na viabilidade celular de C. vulgaris desde 1 ppm, o que parece ser mediado por um estresse oxidativo induzido pelas próprias partículas ou pelos íons Ba2+ liberados no meio de cultura. BT tem um efeito tóxico muito baixo no crescimento de A. flos-aquae, porém ambas partículas afetam a viabilidade celular desde a menor concentração testada, o que ocorre por efeito indireto das mesmas no estresse oxidativo das células. BT apresentou um efeito tóxico estatisticamente significativo (p<0,05) no crescimento e na viabilidade celular de E. gracilis desde 1 ppm, efeito relacionado à endocitose das partículas numa quantidade tal que levou a uma ruptura de suas membranas. BT induziu estresse em todos os organismos-teste, o que foi evidenciado pelo aumento na atividade da superóxido dismutase, pela diminuição da eficiência fotossintética e pela dimuição dos níveis intracelulares de ATP. O comportamento de BT em meios de cultura sintéticos e naturais são diferentes, sendo os efeitos tóxicos mais pronunciados quando o crescimento é dado em água do Rio Sena. O tamanho de BT parece não influenciar os efeitos produzidos sobre o crescimento dos micro-organismos – embora a inibição do crescimento tenha sido pronunciada com o nanomaterial. / In Chapter 1, we aimed to evaluate the performance of the transdermal permeation of Pentravan vehicle for transdermal delivery of coumpounded systems containing progesterone (P), estradiol (E2) and estriol (E3), alone or as a combination of E2 + E3 (Biest). An experimental model of female excised human skin was used to predict the permeation and the retention of the active substances in all skin layers. Moreover, the manufacturing process for formulations were evaluated for content uniformity of the emulsions. The eco-friendly methods developed for quantification of female sex hormones in transdermal emulsions were appropriate, which has been proven through validation studies. The evaluation of the coumpounding process for the emulsions showed that the vacuum packaging currently used by pharmacies are suitable for use, and the use of roll mill played a key role in the uniformity of content for Eemuls and Biest. The in vitro release rates of the drugs from their formulations were adequately high, and all formulations followed pseudo-first order kinetics, typical of semisolid product. The ex vivo permeation study showed that all the formulations were able to promote transdermal absorption of hormones comparable to those currently practiced by industrialized products. In chapter 2, two particles of barium titanate (BT), micro- and nanosized, were evaluated for their impact on aquatic environments. A detailed characterization of the materials was carried out. We used two algae (Chlorella vulgaris and Euglena gracilis) and a cyanobacterium (Anabaena flos-aquae) as model-organisms for assessing toxicity. Both BT MP (microparticle) and BT NP (nanoparticle) were negative, easily aggregated, with a release rate of Ba2+ ions to media that did not exceed 1.5%. BT has a statistically significant toxic effect on cell growth and viability of C. vulgaris, from 1 ppm, which appears to be mediated by oxidative stress induced by the particles themselves or by Ba2+ ions released into the culture medium. BT has a very low toxic effect on the growth of A. flos-aquae, but both particles affect cell viability since the lowest concentration tested, which occurs by indirect effect on the cells. BT has a statistically significant toxic effect on cell growth and viability of E. gracilis, from 1 ppm, related to the effect of endocytosed particles in such an amount that a rupture of their membranes was caused. BT was able to stress all test-organisms, which was evidenced by the increase in superoxide dismutase activity, decreased photosynthetic efficiency and the decreased intracellular ATP levels. The behavior of BT in means of synthetic and natural culture was different, and the most pronounced toxic effects occurred when growth was given in water from the River Seine. The size of BT did not influence the effects on the growth of microorganisms - although growth inhibition has been more pronounced with the nanomaterial.

A combinação de nanopartículas de dióxido de titânio com nanotubos de carbono de parede múltiplas possibilita a geração de um nanomaterial híbrido, com atividade fotocatalítica aprimorada, denominado TiO2-MWCNT. Existe um grande interesse científico e tecnológico em materiais fotocatalíticos, estes apresentam potencial para o desenvolvimento de novos agentes antimicrobianos, nanocompósitos, catalisadores e remediação ambiental. Apesar de muitos trabalhos enfatizarem os benefícios na utilização de nanohíbridos, ainda são escassos estudos de impactos ambientais e toxicidade. O objetivo deste trabalho foi sintetizar e caracterizar o nanohíbrido TiO2-MWCNT, bem como avaliar sua ecotoxicidade aquática através de ensaios in vivo (embriões de Zebrafish - Danio rerio) e in vitro (linhagem celular RTG-2 - fibroblastos de Oncorhynchus mykiss). O TiO2-MWCNT foi sintetizado pelo método mecanoquímico (moagem em estado sólido) e caracterizado empregando as seguintes técnicas: microscopia eletrônica de varredura e de transmissão, espectroscopia Raman, análise termogravimétrica, espalhamento dinâmico de luz e espalhamento de luz eletroforético. O nanohíbrido sintetizado apresentou atividade fotocatalítica aprimorada, confirmada através de ensaios de fotocatálise. Nos ensaios in vivo, o TiO2-MWCNT não apresentou ecotoxicidade aguda até 100 µg mL-1 (na presença ou ausência de radiação UV). No entanto, foi observada a ingestão do nanohíbrido pelos embriões (via oral) através da técnica microfluorescência de raios-X (µ-XRF). Também não foi observado ecotoxicidade para o nanohíbrido nos ensaios in vitro até 100 µg mL-1; porém foi verificado a capacidade de internalização celular deste material. Em geral, aspectos coloidais (agregação/aglomeração) e a formação de protein corona apresentaram importantes implicações para a determinação precisa da ecotoxicidade. Os resultados obtidos neste trabalho suportam futuras aplicações do nanohíbrido TiO2-MWCNT na área de fotocatálise, e contribui de maneira proativa para sua avaliação ecotoxicológica / The combination of titanium dioxide nanoparticles with multiwall carbon nanotubes enables the generation of a hybrid nanomaterial with improved photocatalytic activity, called TiO2-MWCNT. There is great scientific and technological interest in photocatalytic materials, which present potential for the development of new antimicrobial agents, nanocomposites, catalysts and environmental remediation. Although many papers emphasize the benefits of using nanohybrids, there are still a small number of studies about its environmental impacts and toxicity. The objective of this work was to synthesize and characterize a TiO2-MWCNT nanohybrid. As well as to evaluate its aquatic ecotoxicity through in vivo (Zebrafish embryos - Danio rerio) and in vitro (RTG-2 cell line - Oncorhynchus mykiss fibroblasts) assays. TiO2-MWCNT was synthesized by the mechanochemical method (solid state milling) and characterized using the following techniques: scanning and transmission electron microscopy, Raman spectroscopy, thermogravimetric analysis, dynamic scattering light and electrophoretic scattering light. The synthesized nanohybrid showed enhanced photocatalytic activity, confirmed by photocatalysis studies. In the in vivo assays, TiO2-MWCNT did not show acute ecotoxicity up to 100 ?g mL-1 (in the presence or absence of UV radiation). However, the ingestion of the nanohybrid by the embryos (oral route) was observed through ?-probe X-ray fluorescence spectroscopy (?-XRF). Also, no toxicity was observed in the in vitro assays up to 100 ?g mL-1; however, the cellular internalization capacity of this material was verified. In general, colloidal aspects (aggregation / agglomeration) and the formation of protein corona presented important implications for the precise determination of ecotoxicity. The results obtained in this work support future applications of the nanohybrid TiO2-MWCNT in the area of photocatalysis and contributes proactively to its ecotoxicological evaluation