Rozprawy doktorskie na temat „Tributyltin”
Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych
Sprawdź 50 najlepszych rozpraw doktorskich naukowych na temat „Tributyltin”.
Przycisk „Dodaj do bibliografii” jest dostępny obok każdej pracy w bibliografii. Użyj go – a my automatycznie utworzymy odniesienie bibliograficzne do wybranej pracy w stylu cytowania, którego potrzebujesz: APA, MLA, Harvard, Chicago, Vancouver itp.
Możesz również pobrać pełny tekst publikacji naukowej w formacie „.pdf” i przeczytać adnotację do pracy online, jeśli odpowiednie parametry są dostępne w metadanych.
Przeglądaj rozprawy doktorskie z różnych dziedzin i twórz odpowiednie bibliografie.
Miller, Cynthia Elizabeth. "Tributyltin resistance among freshwater sediment bacteria". The Ohio State University, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=osu1346092511.
Pełny tekst źródłaUnger, Michael A. "Investigation of tributyltin: Water/sediment interactions". W&M ScholarWorks, 1988. https://scholarworks.wm.edu/etd/1539616885.
Pełny tekst źródłaBriscoe, Scott F. "Tributyltin : molecular approaches to an environmental problem". Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=85133.
Pełny tekst źródłaBailey, Susan K. "Tributyltin (TBT) contamination in Scottish coastal waters". Thesis, Edinburgh Napier University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.292212.
Pełny tekst źródłaDingle, Pope Nicholas. "The bioavailability of sediment-bound tributyltin (TBT)". Thesis, University of Plymouth, 1998. http://hdl.handle.net/10026.1/2606.
Pełny tekst źródłaCruz, Andreia Sofia Henriques. "Tributyltin (TBT) resistance in Aeromonas molluscorum Av27". Doctoral thesis, Universidade de Aveiro, 2012. http://hdl.handle.net/10773/9545.
Pełny tekst źródłaO tributilestanho (TBT) é considerado um dos xenobióticos mais tóxicos, produzidos e deliberadamente introduzidos no meio ambiente pelo Homem. Tem sido usado numa variedade de processos industriais e subsequentemente descarregado no meio ambiente. O tempo de meia-vida do TBT em águas marinhas é de várias semanas, mas em condições de anóxia nos sedimentos, pode ser de vários anos, devido à sua degradação mais lenta. Embora o TBT tenha sido descrito como sendo tóxico para eucariotas e procariotas, muitas bactérias podem ser resistentes a este composto. O presente trabalho teve como objetivo principal elucidar o mecanismo de resistência ao TBT em bactérias. Para além disso, pretendeu-se desenvolver um biorepórter para detectar TBT no ambiente. Para atingir estes objetivos foram delineadas várias tarefas cujos principais resultados obtidos se apresentam a seguir. Várias bactérias resistentes ao TBT foram isoladas de sedimento e água do Porto de Pesca Longínqua (PPL) na Ria de Aveiro, Portugal. Entre estas, Aeromonas molluscorum Av27 foi selecionada devido à sua elevada resistência a este composto (concentrações até 3 mM), à sua capacidade de degradar o TBT em compostos menos tóxicos (dibutilestanho, DBT e monobutilestanho, MBT) e também por usar o TBT como fonte de carbono. A. molluscorum Av27 foi caracterizada genotipica e fenotipicamente. Os fatores de virulência estudados mostraram que esta estirpe i) possui atividade lipolítica; ii) não é citotóxica para células de mamíferos, nomeadamente para células Vero; iii) não possui integrões de classe I e II e iv) possui cinco plasmídeos com aproximadamente 4 kb, 7 kb, 10 kb, 100 kb e mais de 100 kb. Estes resultados mostraram que a estirpe Av27 não é tóxica, aumentando assim o interesse nesta bactéria para futuras aplicações, nomeadamente na bioremediação. Os testes de toxicidade ao TBT mostraram que este composto tem um impacto negativo no crescimento desta estirpe, bem como, na densidade, no tamanho e na atividade metabólica das células e é responsável pela formação de agregados celulares. Assim, o TBT mostrou ser bastante tóxico para as bactérias interferindo com a atividade celular geral. O gene Av27-sugE, que codifica a proteína SugE pertencente à família das “small multidrug resistance proteins” (SMR), foi identificado como estando envolvido na resistência ao TBT nesta estirpe. Este gene mostrou ser sobreexpresso quando as células crescem na presença de TBT. O promotor do gene Av27-sugE foi utilizado para construir um bioreporter para detetar TBT, contendo o gene da luciferase do pirilampo como gene repórter. O biorepórter obtido reúne as características mais importantes de um bom biorepórter: sensibilidade (intervalo de limite de detecção de 1-1000 nM), rapidez (3 h são suficientes para a deteção de sinal) e, possivelmente, não é invasivo (pois foi construído numa bactéria ambiental). Usando sedimento recolhido no Porto de Pesca Longínqua da Ria de Aveiro, foi preparada uma experiência de microcosmos com o intuito de avaliar a capacidade de Av27 para bioremediar o TBT, isoladamente ou em associação com a comunidade bacteriana indígena. A análise das amostras de microcosmos por PCR-DGGE e de bibliotecas de 16S rDNA revelaram que a comunidade bacteriana é relativamente estável ao longo do tempo, mesmo quando Av27 é inoculada no sedimento. Para além disso, o sedimento estuarino demonstrou ser dominado por bactérias pertencentes ao filo Proteobacteria (sendo mais abundante as Delta e Gammaproteobacteria) e Bacteroidetes. Ainda, cerca de 13% dos clones bacterianos não revelaram nenhuma semelhança com qualquer dos filos já definidos e quase 100% afiliou com bactérias não cultiváveis do sedimento. No momento da conclusão desta tese, os resultados da análise química de compostos organoestânicos não estavam disponíveis, e por essa razão não foi possível tirar quaisquer conclusões sobre a capacidade desta bactéria remediar o TBT em sedimentos. Esses resultados irão ajudar a esclarecer o papel de A. molluscorum Av27 na remediação de TBT. Recentemente, a capacidade da estirpe Av27 remediar solo contaminado com TBT foi confirmada em bioensaios realizados com plantas, Brassica rapa e Triticum aestivum (Silva 2011a), e também com invertebrados Porcellionides pruinosus (Silva 2011B). Assim, poder-se-á esperar que a bioremediação do sedimento na experiência de microcosmos também tenha ocorrido. No entanto, só a análise química dos compostos organostânicos deverá ser conclusiva. Devido à dificuldade em realizar a análise analítica de organoestânicos, um método de bioensaio fácil, rápido e barato foi adaptado para avaliar a toxicidade do TBT em laboratório, antes de se proceder à análise química das amostras. O método provou a sua utilidade, embora tenha mostrado pouca sensibilidade quando se usam concentrações de TBT baixas. Em geral, os resultados obtidos contribuíram para um melhor entendimento do mecanismo de resistência ao TBT em bactérias e mostraram o potencial biotecnológico de A. molluscorum Av27, nomeadamente, no que refere à sua possível aplicação na descontaminação de TBT no ambiente e também no desenvolvimento de biorepórteres.
Tributyltin (TBT) is considered as one of the most toxic xenobiotics, ever produced and deliberately introduced into the environment by Man. It has been used in a variety of industrial processes and subsequently discharged into the environment. The typical half-life of TBT in marine waters is of several weeks, but in deeper anoxic sediments it may be of several years, due to its slower degradation. Although TBT has been reported to be toxic to both eukaryotes and prokaryotes, bacteria can be resistant to this compound. In the present work a major goal was outlined: to elucidate the TBT resistance mechanism in bacteria. Additionally, it was also an objective developing a bioreporter to detect TBT in the environment. For this purpose a number of tasks were delineated and the main results obtained are bellow described. Several resistant bacteria were isolated from sediment and water at Porto de Pesca Longínqua (PPL) site in Ria de Aveiro, Portugal. Among those, Aeromonas molluscorum Av27 was selected due to its high resistance to TBT (up to 3 mM), its ability to degrade this compound into less toxic compounds (dibutyltin, DBT and monobutyltin, MBT) and also because it uses TBT as carbon source. A. molluscorum Av27 was genotypically and phenotypically characterized. The virulence factors studied showed that Av27 strain: i) has lipolytic activity; ii) is not cytotoxic for mammal cells, namely Vero cells; iii) does not have class I and II integrons and iv) possesses five plasmids with approximately 4 kbp, 7 kbp, 10 kbp, 100 kbp and more than 100 kbp. These results demonstrated that Av27 strain is not toxic, increasing the interest on this bacterium for future applications, namely bioremediation. Different growth parameters were studied revealing that a temperature of 25°C, a salinity range from 1 to 4% and a pH between 6 and 9 were the optimal growth conditions to Av27 strain. Regarding the antibiotic resistance profile, A. molluscorum Av27 is resistant to penicillin (10 μg), amoxicillin/clavulanic acid (30 μg) and cephalothin (30 μg) and also to the vibriostatic agent O/129; moreover, Av27 strain uses various compounds as carbon and energy source. TBT toxicity tests showed that this compound has a negative impact on bacterial growth, cell density, cell size and metabolic activity and promoted the formation of cell aggregates. Thus, TBT was found to be very toxic for this bacterium interfering with general cell activity. A gene, Av27-sugE, encoding the SugE protein belonging to the small multidrug resistance (SMR) proteins family was identified to be involved in the TBT resistance in this strain. This gene showed to be over-expressed when cells grow in the presence of TBT. Based on the Av27-sugE putative promoter, a bioreporter for TBT was constructed, containing the firefly luciferase as the reporter gene. The obtained bioreporter gathers the most important characteristics of a good bioreporter: sensitivity (detection limit range from 1-1000 nM), fastness (3 h for signal detection) and possibly non-invasive (it was constructed in an environmental bacterium). A microcosm experiment using estuarine sediment from PPL, Ria de Aveiro, was established to evaluate the ability of Av27 to bioremediate TBT, alone or in association with the indigenous bacterial community. PCR-DGGE and 16S rDNA libraries analysis of the microcosm samples revealed that the bacterial community is relatively stable over time, even when Av27 is inoculated in the sediment. Additionally, the estuarine sediment demonstrated to be dominated by bacteria belonging to the phyla Proteobacteria (among the most abundant Delta and Gammaproteobacteria) and Bacteroidetes. Moreover, about 13% of the bacterial clones showed no similarity to any of the phyla already defined and almost 100% affiliated with unculturable sediment bacteria. At the time of conclusion of this thesis, the results of organotin compounds chemical analysis were not available; therefore it was not possible to draw any conclusions about the TBT remediation in microcosm. Those results will help clarify the role of A. molluscorum Av27 in the remediation of TBT. Recently the ability of Av27 strain to remediate soil contaminated with TBT was confirmed in bioassays performed with plants, Brassica rapa and Triticum aestivum (Silva 2011a) and also invertebrates Porcellionides pruinosus (Silva 2011b). Thus it could also be expected that bioremediation of the sediment from the microcosm experiment has also occurred. Still only the organotin chemical analysis shall be conclusive. Due to the difficulty in performing analytical analysis, an easy, rapid, and inexpensive bioassay method was adapted to monitor TBT toxicity in the laboratory, prior to chemical analysis. The method proved its usefulness albeit showing low sensitivity when low TBT concentrations are used. Overall, the results obtained contributed to the elucidation of TBT resistance in bacteria and revealed the biotechnological potential of A. molluscorum Av27, namely in its possible application to decontaminating TBT in the natural environment and also in the development of bioreporters.
Barros, Ana Rodrigues. "Tributyltin (TBT) effects at a vascular level". Master's thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/16393.
Pełny tekst źródłaOrganotins are an important class man made organometallic compounds and tributyltin (TBT) is one of the most studied chemicals within this class. TBT is a potent endocrine disruptor being also considered as an obesogenic, immunotoxic and neurotoxic compound. Humans were exposed to this and other organotin compounds as a consequence of their widespread commercial applications including plastic stabilizers, catalytic agents and industrial biocides. Their utilization as catalytic agents in the production of silicones leads to the presence of these chemicals in silicone based products including those used in biomedical applications such as breast implants and cardiac valves which may constitute a potential source of exposure. According to the World Health Organization cardiovascular diseases are sharply increasing and constitute the prime cause of death globally. Taking this into account, regulatory agencies, recommend the study of organotin compounds toxicity. Considering the limited number of studies on the cardiovascular effects of organotins, the present thesis aims to elucidate the effects of TBT at the vascular level. The study of TBT effect on the contractility of rat artery (aorta) was performed by the organ bath technique and the L-type calcium channels in A7r5 (cell line derived from the smooth muscle of embryonic rat aorta) was measured by whole-cell configuration of the patch clamp technique. The obtained results demonstrated that TBT seems to relax the rat aorta without endothelium contracted by noradrenaline and potassium chloride but this effect is not significantly different from the respectively ethanol control. The electrophysiological experiments demonstrated that the inhibition of the calcium current by the L-type calcium channels in the A7r5 vascular smooth muscle cells was also not significantly different, which suggests that probably the mode of action of TBT is more complex and involves other pathways.
Os compostos orgânicos de estanho são uma importante classe de compostos organometálicos produzidos pelo homem, e o tributilestanho (TBT) é um dos químicos mais estudados dentro desta classe. O TBT atua como um potente disruptor endócrino, sendo também considerado como um composto obesogénico, imunotóxico e neurotóxico. A exposição humana a este e outros compostos orgânicos de estanho deve-se à sua vasta utilização em aplicações comerciais como estabilizadores de plásticos, agentes catalíticos e biocidas industriais. A sua utilização como agentes catalíticos na produção de silicones faz com que estes compostos estejam presentes em vários produtos à base de silicone, incluindo os usados em aplicações biomédicas como implantes mamários e válvulas cardíacas, o que pode constituir uma fonte potencial de exposição para os humanos. De acordo com a Organização Mundial de Saúde, as doenças cardiovasculares estão a aumentar e são consideradas como a principal causa de morte a nível mundial. Tendo isto em conta, as agências reguladoras recomendam o estudo da toxicidade dos compostos orgânicos de estanho. Considerando o número limitado de estudos sobre os efeitos cardiovasculares dos compostos orgânicos de estanho, o presente trabalho pretende elucidar os efeitos do TBT ao nível vascular. Os efeitos do TBT na contractilidade de artérias de rato (aorta) foram estudados pela técnica do banho de órgãos e a medição dos canais de cálcio tipo L foi realizada em A7r5 (linha celular de músculo liso vascular derivada de aorta embrionária de rato) através da técnica do patch clamp na configuração whole cell. Os resultados obtidos demonstram que o TBT parece induzir relaxamento nas artérias sem endotélio contraídas previamente com noradrenalina e com cloreto de potássio, mas esse efeito não é significativamente diferente do controlo de solvente usado. Nas experiências de eletrofisiologia a inibição das correntes de cálcio através dos canais de cálcio tipo L nas células A7r5 também não mostrou ser significativamente diferente do controlo, o que parece demonstrar que o modo de ação pelo qual o TBT induz efeito nas células vasculares é mais complexo e envolve outras vias.
Gkenakou, Evgenia-Varvara. "The remediation of tributyltin-contaminated dredgings and waters". Thesis, University of Southampton, 2008. https://eprints.soton.ac.uk/67188/.
Pełny tekst źródłaSutton, Benjamin Josiah. "Intramolecular radical additions to pyridines, quinolines and isoquinolines". Thesis, University of Southampton, 2003. https://eprints.soton.ac.uk/426728/.
Pełny tekst źródłaSakultantimetha, Arthit. "Enhancement of tributyltin biodegradation for sustainable remediation of the environment". Thesis, University of Strathclyde, 2010. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=14442.
Pełny tekst źródłaTu, Wai-ki Alex, i 杜偉麒. "Hong Kong marine sediment contamination with Tributyltin and its impacts". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B31254780.
Pełny tekst źródłaTu, Wai-ki Alex. "Hong Kong marine sediment contamination with Tributyltin and its impacts /". Hong Kong : University of Hong Kong, 2000. http://sunzi.lib.hku.hk/hkuto/record.jsp?B22285180.
Pełny tekst źródłaBurton, Edward D., i n/a. "Distribution and Partitioning of Trace Metals and Tributyltin in Estuarine Sediments". Griffith University. School of Environmental Engineering, 2005. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20050830.161359.
Pełny tekst źródłaBangkedphol, Sornnarin. "Case study for sustainable management of tributyltin contamination in the environment". Thesis, University of Strathclyde, 2010. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=12760.
Pełny tekst źródłaSpence, S. K. "Ecotoxicological studies of tributyltin (TBT), using indicatoe species Nucella lapillus (L.)". Thesis, University of Liverpool, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.330259.
Pełny tekst źródłaBurton, Edward. "Distribution and Partitioning of Trace Metals and Tributyltin in Estuarine Sediments". Thesis, Griffith University, 2005. http://hdl.handle.net/10072/366133.
Pełny tekst źródłaThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Environmental Engineering
Full Text
Bao, Wei-wei Vivien. "Toxicities and ecological risks of selected anti-fouling biocides to marine organisms in Hong Kong". Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B43085180.
Pełny tekst źródłaTuroczy, Nicholas John, i mikewood@deakin edu au. "Adsorption and voltammetry of butyltin compounds". Deakin University, 1994. http://tux.lib.deakin.edu.au./adt-VDU/public/adt-VDU20050915.154112.
Pełny tekst źródłaVoulvoulis, Nikolaos. "Environmental analysis and assessment of biocides used in antifouling paints as alternatives to organotin compounds". Thesis, Imperial College London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325576.
Pełny tekst źródłaProud, Sarah Victoria. "Tributyltin pollution and the bioindicator Nucella lapillus : population recovery and community level responses". Thesis, University of Liverpool, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260333.
Pełny tekst źródłaEspourteille, Francois A. "An Assessment of Tributyltin Contamination in Sediments and Shellfish in the Chesapeake Bay". W&M ScholarWorks, 1988. https://scholarworks.wm.edu/etd/1539617592.
Pełny tekst źródłaanderson, Britt-Anne. "Bioremediation of Tributyltin Contaminated Sediment using Spartina alterniflora in a Created Tidal Wetland". W&M ScholarWorks, 2000. https://scholarworks.wm.edu/etd/1539617751.
Pełny tekst źródłaDafforn, Katherine Ann Biological Earth & Environmental Sciences Faculty of Science UNSW. "Anthropogenic modification of estuaries: disturbance and artificial structures influence marine invasions". Awarded by:University of New South Wales. Biological, Earth & Environmental Sciences, 2009. http://handle.unsw.edu.au/1959.4/44778.
Pełny tekst źródłaDoherty, David. "Determination of tributyltin environmental contamination and Kd partition coefficients in sediments using a HPLC analytical method". Thesis, University of Strathclyde, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.502361.
Pełny tekst źródłaChan, Ka Ming. "The use of the rock shell, thais clavigera, as a biomonitor of tributyltin contamination in Hong Kong and Shenzhen". HKBU Institutional Repository, 2008. http://repository.hkbu.edu.hk/etd_ra/860.
Pełny tekst źródłaRice, Charles D. "The influence of tributyltin on various aspects of activation and reactive oxygen formation in oyster toadfish (Opsanus tau) macrophages". W&M ScholarWorks, 1989. https://scholarworks.wm.edu/etd/1539616825.
Pełny tekst źródłaHagelby, Edström Tim. "Obesogenic molecules breaching Caco-2 cells : intracellular regulation of tight junctions". Thesis, Uppsala universitet, Institutionen för biologisk grundutbildning, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-305244.
Pełny tekst źródłaSpooner, Neil. "The effect of Tributyltin (TBT) on the steroid biochemistry of Nucella lapillus, and its possible relationship to the development of imposex". Thesis, University of Liverpool, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317252.
Pełny tekst źródłaBao, Wei-wei Vivien, i 鮑薇薇. "Toxicities and ecological risks of selected anti-fouling biocides to marine organisms in Hong Kong". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hdl.handle.net/10722/210298.
Pełny tekst źródłaRuiz, Jose Miguel. "Metallic pollution in estuaries, with special reference to the effects of tributyltin (TBT) and copper on the early life stages of Scrobicularia plana (Mollusca: Bivalvia)". Thesis, University of Plymouth, 1993. http://hdl.handle.net/10026.1/2480.
Pełny tekst źródłaBijoux, Hugues. "Etude des impacts toxiques des contaminants chimiques du Bassin d'Arcachon sur l'huitre cultivée Crassostrea gigas : Approche in-situ et expérimentale". Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0078/document.
Pełny tekst źródłaThe Arcachon Bay is a semi-enclosed lagoon and represents the core of strong economic stakes through the practice of oyster-farming. This activity has been affected for around thirty years by summer mortality events, and more recently by abnormally high death rates of juveniles. This work focused on the role of the Arcachon Bay’s main contaminants in this crisis, by studying their effects on the cupped oyster’s biology. Firstly, an in situ approach was adopted in order to identify the major pollutants of the bay: caged oysters were transplanted and sediments were sampled. The presence of contaminants in the samples was associated to biological responses. Secondly, the contaminants identified in situ were used in controlled conditions at the laboratory. Three experimentations were performed; the first dealt with the contamination pathways of tributyltin; the second focused on the biological effects of pesticides and copper; the third concerned the effects of PAH towards diploid and triploid oysters. Our results indicate that the inner stations present higher accumulation of metals and PAH, in accordance with the hydrodynamic features of the bay. The bioindicators used in situ exhibited seasonal trends related to the oysters’ gametogenesis. In the laboratory, most of the contaminants used at environmental levels induced an adaptive response of the exposed oysters. Our study highlights the importance of coupling in situ and laboratory approaches in order to understand the functioning of coastal ecosystems
Sabah, Aboubakr. "Présence et comportement des butylétains dans les stations d'épuration des eaux usées par lagunage naturel". Thesis, Montpellier, 2016. http://www.theses.fr/2016MONTS020/document.
Pełny tekst źródłaThis thesis deals with the behavior of a priority compound on the basis of the framework Directive on water at European level: tributyltin (TBT) ) and its metabolites (dibutyltin (DBT) and monobutyltin (MBT)). The study is focused on two waste stabilization pond treatment plants (WSP), which is an appropriate treatment to domestic effluents from sparsely urbanized areas.This thesis comes to fill the lack of scientific results on (1) the level of butyltin concentrations in domestic effluents from sparsely urbanized areas, in the input of the WSP and the output after treatment; (2) the efficiency of butyltins elimination by the WSP treatment; (3) the identification of the processes that control the fate of these elements during the treatment.Butyltins are measured in particulate and dissolved matrices and in sludge, by GC-ICP-MS, in all stages of the treatment by lagooning of two villages of the Department of Hérault (34, France): Gigean (6000 p.e.) and Montbazin (4500 p.e.).It is shown that the three butyltin species are consistently present in all samples taken from the two WSP. Butyltins arrive primarily in particulate form in the raw water. During treatment, the processes of sorption onto particulate matter and the settling of the latter at the bottom of each basin are the main factors for the elimination of butyltins. The first anaerobic ponds, characterized by deep depth and long residence times, allow the elimination of more than 60% Gigean (93% at Montbazin) of butyltins. Bottom sludge of each basin show high butyltins concentrations. The resuspension of butyltins is noted in the last maturation ponds, characterized by shallow depth, which may be due to re-thermal stratification. At the outlet, despite significant butyltin removal, concentrations in butyltins remain high (12 to 228 and 1.8 to 15 ng (Sn). L-1, respectively for Montbazin and Gigean).Laboratory batch experiments were conducted to study sorption processes following several experimental protocols. It was thus shown that: (1) the distribution of the butyltin species between solid and liquid phases is different from one test to another according to the operating conditions; (2) the affinity between butyltins and bottom sludge is important, regardless of its provenance. 98% of the butyltins are found in the solid phase, due to their hydrophobicity. The TBT sludge-water partition coefficient is higher than that obtained for other type of solid phases (75000 L.kg-1); (3) the process of sorption is fast.Moreover processes of sorption, desorption and dealkylation of TBT, explaining changes in concentrations of MBT and DBT in the solid phase were identified. Desorption of TBT is fast. It degrades in the liquid phase in DBT which part turns into MBT. The sorption of MBT on sludge has been systematically measured. Therefore, the sorption phenomenon is not completely reversible over time. These results help to explain the dysfunctions observed in WSP, for example after direct inputs of rainwater.This thesis shows the systematic presence of butyltin in waste stabilization pond treatment plants. In-situ data coupled with laboratory tests allow to understand the behaviour of these compounds during this treatment: the solid fraction plays a key role in the processes of sorption-desorption-(bio) degradation of butyltins
Laranjeiro, Filipe Miguel Grave. "The use of Imposex/Intersex as a tool to assess the ecological quality status of water bodies". Doctoral thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/17767.
Pełny tekst źródłaA Directiva Quadro da Água (DQA) foi introduzida pela União Europeia (UE) em 2000 com o objetivo de proteger as águas de superfície (interiores, de transição e costeiras) e subterrâneas. Esta ambiciosa directiva lançou novos desafios, entre os quais a necessidade de desenvolver novas ferramentas ecotoxicológicas para a avaliação do estado ecológico das massas de água. O tributilestanho (TBT), um biocida amplamente utilizado em tintas antiincrustantes e identificado como agente causador do fenómeno de imposex / intersex em gastrópodes, está incluído na lista de substâncias prioritárias da DQA. No entanto, esta directiva não considera qualquer ferramenta de biomonitorização específica para avaliar os efeitos nocivos do TBT nos ecossistemas. O único objetivo concreto para esta substância é referido nas Normas de Qualidade Ambiental (NQA) e atingido a 0,2 ng TBT / L (NQA - Média Anual). Mais tarde, em 2008, a Directiva Quadro da Estratégia Marinha (DQEM) foi introduzida na UE com objectivos semelhantes à DQA, mas direcionada para águas marinhas. No entanto, uma vez mais, não foi proposta nenhuma ferramenta ecotoxicológica para a monitorização dos efeitos biológicos provocados por este poluente. Assim, de forma a integrar a biomonitorização da poluição por TBT ao abrigo destas directivas, esta tese tem como objetivo desenvolver e testar, sob diferentes cenários, ferramentas baseadas nos biomarcadores imposex/intersex para avaliar o estado ecológico de massas de água. Assim, é proposto um sistema de classificação baseado nos níveis de imposex/intersex de populações de gastrópodes para avaliar o estado ecológico de águas costeiras e de transição, relativamente à poluição por TBT. Utilizando a Ria de Aveiro (NW Portugal) como estudo de caso, três bioindicadores - os gastrópodes Nucella lapillus, Nassarius reticulatus e Littorina littorea - foram utilizados tendo em conta o elemento de qualidade biológica para invertebrados bentónicos da DQA, de forma a classificar o estado das massas de água desta região. O índice de sequência do vaso deferente (VDSI) e o índice de intersex (ISI) foram os parâmetros de imposex/intersex selecionados para avaliar o estado ecológico, relativamente à poluição por TBT. Os limites definidos pelos Rácios de Qualidade Ecológica (EQR) foram obtidos para cada espécie, a fim de definir as cinco classes de estado ecológico (Excelente, Bom, Razoável, Medíocre e Mau). A espécie N. lapillus é proposta como bioindicador chave na monitorização da poluição por TBT, no entanto, o uso combinado das outras espécies revela-se muito útil porque permite monitorizar uma área maior e uma maior diversidade de habitats. Esta ferramenta de monitorização multiespecífica demonstrou ser bastante útil para avaliar a evolução temporal do estado ecológico das massas de água da Ria de Aveiro entre 1998 e 2013, que demonstrou uma clara melhoria, alcançando um bom estado ecológico em 2013. Este trabalho propõe também uma outra ferramenta destinada a avaliar a qualidade dos sedimentos. Esta ferramenta consiste num bioensaio em que se expõem fêmeas de N. reticulatus a sedimentos recolhidos no ambiente para determinar se ocorre um aumento de imposex. Este bioensaio provou ser uma ferramenta complementar e com relevância ecológica na monitorização da poluição por TBT na medida em que fornece informação sobre a fracção biodisponível de TBT nos sedimentos e permite avaliar locais onde não existem bioindicadores disponíveis. Para testar o uso de ambas ferramentas em programas de monitorização da DQA, estas foram aplicadas em dois sistemas estuarinos - Minho e Lima - localizados no Norte de Portugal. A monitorização de imposex evidenciou um bom estado ecológico no Minho mas o estuário do Lima não conseguiu alcançar o objetivo de bom estado ecológico, apresentando locais com um estado "moderado" ou de qualidade inferior. Em conformidade, o bioensaio com sedimentos confirmou a presença de TBT biodisponível apenas nos sedimentos do estuário do Lima, já que se observou o aumento de alguns parâmetros de imposex com estes sedimentos. O uso combinado destas ferramentas permitiu aumentar a área de monitorização nestes sistemas estuarinos, uma vez que não foi possível encontrar bioindicadores em todas as estações de amostragem, sendo nesse caso obtidas apenas amostras de sedimento. O critério proposto para a monitorização de imposex na DQA foi também testado ao longo da costa portuguesa de forma a avaliar a evolução do estado ecológico de 2000 a 2014. Em 2014, as fêmeas de N. lapillus colhidas em praias ao longo da costa exibiram baixos níveis de imposex, exceto numa estação situada na Zambujeira do Mar (SW Portugal) onde foram encontradas fêmeas estéreis. Já as fêmeas de N. reticulatus mostraram baixos níveis de imposex na maioria das estações amostradas, porém elevados níveis foram observados em áreas sujeitas a um intenso tráfego naval. Comparando estes valores com os observados em anos anteriores, é possível perceber que ambas as espécies recuperaram de forma significativa ao longo dos últimos 15 anos. N. lapillus apresentou uma redução dos níveis de imposex mais pronunciada do que N. reticulatus, porém esta diminuição parece ter abrandado nos últimos anos (2011-2014), prevendo-se uma estabilização por algum tempo em níveis muito baixos. N. reticulatus também mostrou uma diminuição gradual, mas os valores de imposex indicam uma recuperação mais lenta em portos de pesca e marinas. Isto representa uma mudança das principais fontes de poluição por TBT, já que os níveis de imposex em grandes portos comerciais, outrora locais altamente poluídos, caíram rapidamente. Assim, na costa Portuguesa, o bom estado ecológico foi alcançado na maior parte das estações localizadas em águas costeiras, no entanto uma qualidade ecológica inferior foi observada em massas de água de transição, especialmente onde estão localizados portos de pesca e marinas. A classificação da qualidade ecológica da costa portuguesa segundo a DQA (proposta apresentada nesta tese) e a OSPAR, relativamente à poluição por TBT, é analisada no presente trabalho. Esta comparação é da maior importância, pois tanto as premissas da DQA, como as ferramentas de monitorização utilizadas pelas convenções regionais marinhas (por exemplo a OSPAR) devem ser integradas na aplicação da DQEM. As classificações obtidas segundo a DQA e a OSPAR apresentam um resultado global muito semelhante para 2014, e ambas denotam uma apreciável recuperação do estado ecológico ao longo dos últimos anos. A integração da monitorização de imposex/intersex na DQEM é aqui recomendada e discutida, tendo em conta possíveis divergências nos objetivos definidos por cada legislação e os meios para alcançá-los. Mesmo que a utilidade das ferramentas empregadas para monitorizar a poluição por TBT tenham sido comprovadas, a monitorização de imposex/intersex a ser aplicada na DQA e DQEM só será eficaz se: (i) houver uma boa escolha de bioindicadores; (ii) o imposex/intersex constituírem uma resposta específica para a poluição por TBT porque se outros contaminantes tiverem a capacidade de induzir imposex ou intersex, estes biomarcadores perdem grande parte do seu valor operacional. Por estas razões, esta tese apresenta ainda alguns resultados que devem ser considerados para a validação da utilização do imposex/intersex na monitorização da poluição por TBT. A Ria de Aveiro é uma área que tem sido intensamente estudada em relação à poluição por TBT e, conforme descrito anteriormente, apresentou uma importante melhoria do estado ecológico em relação a este poluente prioritário. No entanto, uma tendência contrária foi observada na evolução dos níveis de imposex no gastrópode Peringia ulvae. Esta espécie - considerada por vários autores como um bom bioindicador da poluição por TBT - não demonstrou uma recuperação dos níveis de imposex, apesar dos níveis de TBT e de imposex/intersex noutras espécies terem vindo consistentemente a diminuir nesta área. Em vez disso, houve um aumento global na percentagem de fêmeas afetadas por imposex e nos níveis de VDSI até 2012, sendo que os níveis de imposex em 2015 são ainda semelhantes aos encontrados em 1998. As possíveis razões para o padrão contracorrente observado nesta espécie podem estar relacionados com a interferência de outros factores que influenciam a expressão do imposex; por exemplo, a indução de imposex por parasitas - que são difíceis de controlar quando a monitorização é realizada com esta espécie - pode enviesar a interpretação dos resultados. É, portanto, necessária uma escolha criteriosa dos bioindicadores a utilizar no âmbito das directivas DQA e DQEM. O imposex não é apenas um efeito exclusivo do TBT, uma vez que já foi descrito que o trifenilestanho (TPT) pode também causar este fenómeno em algumas espécies de gastrópodes. Aqui, é descrita, pela primeira vez, a indução de imposex por TPT em N. lapillus, a espécie que foi proposta como bioindicador chave na DQA. Curiosamente, o desenvolvimento do imposex em fêmeas de N. lapillus injetadas com TPT é diferente das injectadas com TBT, uma vez que as primeiras desenvolvem uma via de imposex principalmente afálica (sem desenvolvimento do pénis). Estes resultados sugerem que o TPT e o TBT podem agir de forma diferente no processo de masculinização de fêmeas de gastrópodes, lançando novas perspectivas sobre as hipotéticas vias subjacentes ao desenvolvimento de imposex. É importante saber se existem outros contaminantes, para além dos organoestânicos, capazes de induzir (ou interferir com) o desenvolvimento de imposex ou intersex, com vista à validação das ferramentas de monitorização propostas nesta tese. Para tal, um ensaio com um gene repórter foi realizado em células transfectadas com recetores humanos, cujos ortólogos foram anteriormente identificados em gastrópodes (RXR, PPAR, ER e RAR). Sabendo que o imposex é causado pela ativação dos recetores nucleares RXR e PPARy por parte do TBT e TPT, é importante perceber se outros contaminantes são capazes de ativar estes recetores. Testaram-se vários contaminantes ambientais e mesmo que algumas substâncias tenham tido a capacidade de ativar ligeiramente o RXR e PPARy, nenhuma foi capaz de o fazer com uma potência semelhante ao TBT e TPT, sugerindo que estas são as únicas substâncias testadas capazes de induzir imposex para concentrações ambientalmente relevantes. Não obstante, todas as substâncias que foram capazes de ativar os recetores foram identificadas e o seu potencial para causar disrupção endócrina nos gastrópodes é discutido. Em conclusão, as ferramentas propostas nesta tese podem ser extremamente úteis na monitorização do ambiente aquático ao abrigo das recentes directivas da União Europeia. Em Portugal existem três peças legislativas que se sobrepõem espacialmente nas águas costeiras (DQA, DQEM e OSPAR) e águas de transição (DQA e OSPAR), e podem diferir nos seus objetivos específicos relativamente à poluição por TBT. Logo, existe uma necessidade urgente de encontrar objetivos comuns na UE, tanto químicos e biológicos, para este poluente. Para além disto, e num momento em que a busca de modelos biológicos não vertebrados está a aumentar em ecotoxicologia, esta tese realça o uso de gastrópodes como uma possível opção. O trabalho desenvolvido nesta tese mostra que a poluição por TBT tem vindo a diminuir em Portugal mas ainda existem alguns locais onde os níveis são altos e não atingem os objectivos definidos pela OSPAR e pela DQA (segundo a proposta aqui apresentada). As ferramentas propostas nesta tese podem ser úteis para acompanhar a evolução da situação em Portugal e na UE nos próximos anos e identificar os locais onde será necessário melhorar a qualidade ecológica das massas de água relativamente a esta substância prioritária, de acordo com as metas estabelecidas pela legislação vigente.
The Water Framework Directive (WFD) was introduced in the European Union (EU) in 2000 with the objective to protect the EU surface waters (inland, transitional and coastal) and ground waters. This ambitious directive raised new challenges, as the need to develop quick and low-cost effect-based monitoring tools, which are increasingly being recommended to perform a proper environmental assessment under this directive. Tributyltin (TBT), a biocide largely used in antifouling paints and identified as a causative agent of imposex/intersex in gastropods, is listed as a priority substance in WFD. However, this directive does not consider any particular biomonitoring tool to assess TBT deleterious effects on the ecosystems. The only explicit objective for TBT regards the Environmental Quality Standard (EQS – Annual Average = 0.2 ng TBT/L). Later on, in 2008, the Marine Strategy Framework Directive (MSFD) was introduced in the EU with similar objectives but specifically related to marine waters that again failed to propose an effect based tool to monitor this pollutant. Therefore, to integrate TBT pollution monitoring within these legislative frameworks, it is the aim of this thesis to develop effect based tools centred on the imposex/intersex biomarkers in order to assess the ecological quality status of EU water bodies regarding TBT pollution. This work proposes a scoring system based on imposex/intersex levels to assess the WFD ecological quality status regarding TBT pollution of transitional and coastal waters. Taking Ria de Aveiro (NW Portugal) as a case study, three bioindicators – the gastropods Nucella lapillus (dog-whelk), Nassarius reticulatus (netted-whelk) and Littorina littorea (periwinkle) - were used under the general WFD benthic invertebrate quality element to classify the ecological status of this area. The vas deferens sequence index (VDSI) and the intersex index (ISI) were selected as biomarkers to assess the condition of this quality element regarding the impact of TBT pollution. EQR boundaries were set for each species in order to define the five ecological status classes (High, Good, Moderate, Poor and Bad). N. lapillus is proposed as a key bioindicator species, however the combined use of further species is very useful to cover a wider monitoring area and a higher diversity of habitats. This multi-species monitoring tool was useful to assess the temporal evolution of the ecological status of Ria de Aveiro water bodies between 1998 and 2013, showing that all the surveyed area improved and reached a good ecological status in 2013. This work also proposes other imposex based tool that allows to evaluate the sediment quality, regarding TBT pollution. The use of this bioassay has proven to be a practical and ecological relevant tool as (i) it can give information for sites with no native populations of snails, (ii) it provides early identification of polluted sites anticipating future imposex levels or early identification of recovering, and (iii) it yields information on the bioavailable fraction of the TBT in the sediment. Therefore, this tool can also be of extreme usefulness under the scope of recent European legislative frameworks. To confirm the suitability of the above mentioned tools in WFD monitoring programs, they were both applied in two estuarine systems - Minho and Lima - located in NW Portugal. The imposex field monitoring evidenced a good ecological status in Minho while the Lima estuary fail to reach the WFD good ecological status objective by presenting sites with “Moderate” and “At Best Poor” ecological status. Accordingly, the sediment bioassay confirmed the presence of bioavailable TBT only in the Lima sediments. The combined use of these tools allowed to increase the monitoring area in these estuarine systems and enhanced the robustness of the assessment, as the bioindicators fail to exist at many sites of the study area. The proposed criteria for imposex monitoring under the WFD was tested along the Portuguese coast to assess the evolution of the ecological status from 2000 to 2014, using N. lapillus and N. reticulatus as bioindicators. Lately, the dogwhelks collected in coastal shores exhibited low imposex levels, except at one station in Zambujeira do Mar (SW Portugal) where sterile females were still found. Accordingly, the netted-whelk showed low levels of imposex at the majority of the sampled stations but high levels were still observed at areas subjected to intense naval traffic. When comparing these data regarding the most recent years with past imposex levels, it is perceived that both species recovered significantly over the last 15 years. N. lapillus presented a more pronounced decrease in imposex levels than N. reticulatus, however this declining trend decelerated from 2011 to 2014. N. reticulatus also showed a gradual decrease but the imposex values indicate a slower recovery at fishing harbours and marinas, which represents an apparent shift in the TBT hotspots as imposex levels in large commercial ports fell rapidly. Consequently, in the Portuguese coast a good ecological status was achieved in most of the stations located in coastal waters while a worse ecological quality was observed in transitional water bodies where fishing ports and marinas are located. A comparison between the proposed WFD imposex tool and the OSPAR Assessment Criteria for imposex shows that both classifications schemes present a general similar result for 2014 and point to a clear recovery of the quality status over the years. This comparison between two legislations is of foremost importance since both WFD premises and Regional Sea Conventions (e.g OSPAR) knowledge and monitoring tools should be integrated by member states on the application of the MSFD. Therefore the imposex/intersex monitoring integration within MSFD is discussed taking into account possible divergences between the objectives defined by each piece of legislation and the means to achieve it. Even if the usefulness of the employed tools to monitor TBT pollution has been proved, the WFD’s monitoring proposal will only be effective if: i) there is a good choice of the bioindicators species; and ii) imposex/intersex are specific responses to TBT pollution, i.e., if other contaminants induce imposex or intersex, then these biomarkers lose much of their operational value. For that reason this thesis presents novel information regarding these aspects in order to validate this methodology and better interpret the obtained results. Ria de Aveiro is an area that has been intensively studied regarding TBT pollution and, as previously reported, presented a major improvement of the ecological status regarding this priority pollutant. An opposite trend has been however observed in the imposex evolution in the gastropod Peringia ulvae. This species - regarded by some authors as a good bioindicator of TBT pollution - did not show an imposex recovery despite the fact that TBT levels have been consistently decreasing in this area. Instead, there was a global increase in the percentage of females affected by imposex and VDSI levels until 2012, and the imposex levels in 2015 were similar to those found in 1998. Possible reasons for this counter current pattern could be related with other factors that can influence imposex expression, such as parasitism, that probably cannot be totally controlled when monitoring is performed with this species. Hence, there is the need to carefully choose the right bioindicators to implement TBT monitoring assessments under WFD or MSFD, and P. ulvae is not recommended for this purpose. Imposex is not an exclusive response to TBT since triphenyltin (TPT), a related organotin, is already known to cause the same phenomenon in some gastropod species. This thesis describes, for the first time, that TPT also induces the development of imposex in N. lapillus, the species considered the key bioindicator in the WFD monitoring proposal. However, imposex development in TPT-injected females followed mostly an aphallic route (no penis development). These results suggest that TPT and TBT may act differently in the sequential process of female masculinization casting new insights about the hypothetical pathways underlying imposex development. Besides TBT and TPT, it is important to know if other environmental contaminants can induce or interfere with the imposex/intersex development to ensure that the proposed tools are specific to organotin pollution. With this purpose, a reporter gene assay was performed using the GAL4/UAS system in cells transfected with human receptors, which were already identified in gastropods: Retinoid X Receptor (RXR), Peroxisome Proliferator-Activated Receptor gamma (PPARγ), Retinoic Acid receptor (RAR) and Estrogenic Receptor (ER). It has been reported in the literature that imposex is caused by the activation of the nuclear receptors RXR and/or PPARγ by TBT or TPT, and therefore if other contaminants can bind these receptors they could have the potential to induce imposex/intersex as well. Even if there were other substances that slightly activated RXR and PPARγ, none was able to do it with similar potency than the organotins (TBT and TPT), suggesting so far that these are the only tested substances capable to induce imposex at realistic environmental concentrations. Nevertheless, all substances that were able to activate the reporter gene were identified and their potential to cause endocrine disruption in gastropods is discussed. Concluding, the tools proposed in this thesis can be of extreme utility to monitor the aquatic environment under the frame of the recent EU directives. Moreover, in Portugal there are three legislative pieces that are spatially overlapped regarding coastal waters (WFD, MSFD and OSPAR) and transitional waters (WFD and OSPAR), and they may differ in their specific objectives regarding TBT pollution. Therefore there is a need to find common EU objectives, both chemical and biological, for this pollutant. Furthermore, in a time where the search of non-vertebrate biological models in ecotoxicology is increasing, this thesis enhances the use of gastropods as an option. Also the work here developed shows that TBT pollution has been decreasing in Portugal but there are some sites where levels are still high. In this scenario, the tools here proposed can be useful to track the evolution of TBT pollution during the next years and to identify waters bodies that will require an action to improve their ecological status.
Souto, Márcia Alexandra Miranda. "The course of TBT pollution in the world during the last decade". Master's thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/13976.
Pełny tekst źródłaOrganotins (OTs) are organometallic compounds. Despite of the multiple applications of the OTs, the notoriety of these compounds is due to tributyltin (TBT), a potent biocide used in antifouling paints since the 60s to prevent biofouling on submerged surfaces, including the hulls of ships. Despite of the extreme effectiveness of these paints in combating biofouling, they are also extremely toxic to non-target organisms, therefore several legislative measures restricting their use were implemented in several countries worldwide. TBT causes a huge variety of adverse effects on non-target species (sublethal / lethal) of different taxonomic groups (from bacteria to mammals). The first evidence of adverse effects induced by TBT on non-target species emerged in the 70s in oysters of the species Crassostrea gigas in the Bay of Arcachon, France. Their shells have suffered thickening with consequent decrease in the volume of edible portion, reducing its commercial value. In the same decade was verified the occurrence of male sexual characteristics in female prosobranch gastropods (formation of a penis and / or development of a vas deferens), by exposure to TBT. This phenomenon was coined as "imposex" by Smith in 1971. The imposex is the best known example of endocrine disruption caused by a pollutant being used as a biomarker to monitoring the environmental pollution by TBT. The gastropods are used globally for monitoring environmental pollution by TBT. In the present work we studied how gastropods have been used to track the course of TBT pollution worldwide during the last decade (2003-2013), and the main results obtained. We searched for the number of published articles by year / continent and country regarding the bioindicator species most used in biomonitoring TBT pollution in function of their geographical location; we evaluated the efficacy of the AFS Convention in reducing TBT pollution worldwide; we evaluated the temporal evolution (2003-2013) of the levels of imposex by bioindicator species and geographical area, as well as the concentration of OTs in the biota, water and sediments. There was noticed an increase of the number of publications for monitoring environmental pollution by TBT in 2008, coincident with the time of entry into force of the AFS Convention and a gradual decrease of the number of publications from 2008 to 2013, after the entry into force of this Convention; most of the monitoring studies developed in the period 2003-2013 were conducted in Europe, followed by the continents: America, Asia, Africa e Oceania; in this period were used 96 bioindicator species of imposex, being that the 5 more used were: Nucella lapillus, Hexaplex trunculus, Nassarius reticulatus, Stramonita haemastoma and Thais clavigera. A greater diversity of bioindicators was used in America and Asia compared to Europe, whist Africa and Oceania were the continents with smaller number of bioindicator species used. Regardless of the geographic region, and despite the wide diversity of species used, the bioindicators were all caenogastropods (Subclass Caenogastropoda) and most frequently of Order Neogastropoda and Littorinimorpha, being the majority from family Muricidae. There was a decrease of the levels of imposex in the different bioindicators used by continent and country, as well as a decline of the concentrations of OTs in biota, water and sediments, by continent and country, since the entry into force of the AFS Convention in September 2008.
Os organoestânicos (OTs) são compostos organometálicos. Apesar das múltiplas aplicações dos OTs, a notoriedade destes compostos, no que diz respeito a fenómenos de poluição, é devida ao tributilestanho (TBT), um potente biocida usado em tintas antivegetativas desde a década de 60 para prevenir a bioincrustação nas superfícies imersas, nomeadamente nos cascos de embarcações. Apesar da extrema eficácia destas tintas no combate à bioincrustação são também extremamente tóxicas para organismos não-alvo pelo que várias medidas legislativas restringindo o seu uso foram implementadas em vários países. O TBT provoca uma enorme variedade de efeitos nefastos em espécies não- alvo (sub-letais / letais) de diferentes grupos taxonómicos (de bactérias a mamíferos). A primeira evidência de efeitos nefastos induzidos pelo TBT em espécies não alvo surgiu na década de 70 em ostras da espécie Crassostrea gigas na Baía de Arcachon, França. As suas conchas sofreram um espessamento com a consequente diminuição do volume da parte comestível, diminuindo o seu valor comercial. Na mesma década verificou-se a ocorrência de características sexuais masculinas em fêmeas de gastrópodes prosobrânquios (formação de um pénis e/ou desenvolvimento de um vaso deferente), por exposição ao TBT. Esse fenómeno foi designado de "imposex" por Smith em 1971. O imposexo é o melhor exemplo conhecido de disrupção endócrina provocada por um poluente sendo utilizado como biomarcador para monitorizar a poluição ambiental por TBT. resumo (cont.) Nesta tese fez-se um levantamento da metodologia utilizada na monitorização da poluição por TBT a nível mundial durante a última década (2003-2013), nomeadamente, o número de artigos publicados por ano/continente e país sobre as espécies bioindicadoras do imposexo mais utilizadas na biomonitorização da poluição por TBT nesta década e em função da sua localização geográfica. Neste trabalho avaliou-se, também, a eficácia da Convenção AFS na redução da poluição por TBT a nível mundial, através da evolução temporal (2003-2013) dos níveis de imposexo por espécie bioindicadora e zona geográfica, e avaliou-se a evolução temporal (2003-2013) da concentração de OTs no biota, água e sedimentos por zona geográfica. Verificou-se um aumento do número de publicações de monitorização da poluição ambiental por TBT em 2008, coincidente com o momento de entrada em vigor da Convenção AFS; um decréscimo gradual do número de publicações de 2008 a 2013, após a entrada em vigor da Convenção AFS; a maioria dos estudos de monitorização no período 2003-2013 foi realizada na Europa, seguindo-se os continentes: America, Ásia, África e Oceania; neste período foram usadas 96 espécies bioindicadoras de gastrópodes (imposex), sendo que as 5 mais utilizadas foram: Nucella lapillus, Hexaplex trunculus, Nassarius reticulatus, Stramonita haemastoma e Thais clavigera. Neste trabalho é possível verificar a utilização de uma maior diversidade de espécies bioindicadoras na América e na Ásia em relação à Europa, África e Oceania são os continentes que apresentam menor número de espécies bioindicadoras. Independentemente da região geográfica onde foram realizados os estudos, e apesar da grande diversidade de espécies utilizadas, os bioindicadores foram todos caenogastropodes (subclasse Caenogastropoda) e mais frequentemente das ordens Neogastropoda e Littorinimorpha, sendo a maioria da família Muricidae. Neste trabalho também é possível verificar descida dos níveis de imposexo nas diferentes espécies bioindicadoras, utilizadas por continente e país, e descida das concentrações de OTs no biota, água e sedimentos, por continente e país, desde a entrada em vigor da convenção AFS em Setembro de 2008.
Ouadah-Boussouf, Nafia. "Analyse in vivo de la dynamique du tissu adipeux blanc après exposition à des polluants chimiques ou à des molécules pharmacologiques chez le poisson zèbre". Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14755/document.
Pełny tekst źródłaAn unbalanced diet and / or the presence of exogenous compounds contaminants mayalter endocrine signaling and lipid homeostasis and induce obesity. The work done in thisthesis have, at first, developed a simple and rapid method, called "zebrafish obesogenic (ZO)test" to identify in vivo by using the zebrafish larva, the factors that may increase or decreasethe size of the white adipocyte and therefore modulate the level of adiposity (Tingaud-Sequeira, Ouadah, Babin, J. Lipid Res. 52, 1765-1772, 2011). This test helps to identifycompounds and mixtures of obesogenic and anti-obesogenic molecules and providesinformation relevant to the risk assessment of their presence but also to elucidate themechanisms involved. Work in a second time allowed to answer as to how the action oftributyltin chloride, a powerful obesogenic contaminant found widely in the environment.This molecule acts in vivo on white adipocytes in a concentration of the order of nano molarvia nuclear receptors LXR and RXR, and not via the PPARgamma isoforms / delta (Ouadahand Babin, manuscript in preparation)
Moufid, Nadira. "Cyclisations radicalaires en série glucidique". Nancy 1, 1990. http://www.theses.fr/1990NAN10306.
Pełny tekst źródłaSarradin, Pierre-Marie. "Répartition et évolution du tributylétain dans les sédiments marins". Pau, 1993. http://www.theses.fr/1993PAUU3031.
Pełny tekst źródłaBenoit, Christelle. "Biogéochimie et enregistrement des composés organostanniques dans les sédiments du Bassin d'Arcachon". Bordeaux 1, 2005. http://www.theses.fr/2005BOR12988.
Pełny tekst źródłaThe majority of environmental contaminants arise from various anthropic activities. Most of them could have dramatic consequences on the ecosystems and on the natural equilibrium. TBT is one of the most toxic contaminants introduced in the marine environment on a large scale since the early 70'. The damaging effects caused by TBT to aquatic organisms have initially been observed in the Bay of Arcachon at the end of the 70's. TBT contamination was found to be responsible for failure in reproduction and for anomalies occurring in the shell calcification leading to stunted growth. Although TBT inputs have decreased due to restrictive regulations, important contamination levels are still reported by numerous and various environmental studies, particularly in port and harbour areas. The aim of the present work was to assess contamination of the sediment by organotin compounds in the Bay of Arcahon. Sediment core analysis permitted a recording of the contamination and organotin depth profil of the sediment. Additionally sedimentation rates in different port areas and a chronology of the contamination have been estimated by 210Pb analysis. Finally, due to the problems concerning dredging material management, we have performed a preliminary study on the sediment decontamination by electrokinetic process
Vogt, Christian. "Schadstoffeffekte auf Entwicklung, Reproduktion und genetische Variabilität Multigenerationsstudien mit der Zuckmücke Chironomus riparius und Tributylzinn". Göttingen Cuvillier, 2007.
Znajdź pełny tekst źródłaAmardeil, Régine. "L'hydrure de tributyletain en synthèse organique : sélectivité sous haute pression". Bordeaux 1, 1989. http://www.theses.fr/1989BOR10569.
Pełny tekst źródłaHuet, Martial. "Estimation de la pollution par le tributylétain (TBT) en Bretagne occidentale à l'aide d'un bioindicateur imposex chez Nucella Lapillus (L. )". Brest, 1996. http://www.theses.fr/1996BRES2050.
Pełny tekst źródłaHorry, Habib. "Développement d'un biocapteur bactérien bioluminescent pour la détection d'organoétains". Nantes, 2004. http://www.theses.fr/2004NANT2136.
Pełny tekst źródłaLeguille, Francis. "Etude fondamentale du comportement du tributylétain dans un système eau/sédiment". Pau, 1992. http://www.theses.fr/1992PAUU3002.
Pełny tekst źródłaSiah, Ahmed. "Rôle de la progestérone dans la maturation de Mya Arenaria et étude de l'effet d'un perturbateur endocrinien : le tributylétain (TBT) sur le niveau des hormones stéroi͏̈diennes". Nantes, 2003. http://archive.bu.univ-nantes.fr/pollux/show.action?id=5361c751-d482-45ac-86c6-c33fb0f3fafb.
Pełny tekst źródłaThe goals of this study were to examine the link between progesterone and gametogenesis and Tributyltin (TBT) effects on steroid hormones (progesterone, testosterone and 17 -estradiol) in Mya arenaria. Progesterone has been characterized in the gonad of Mya arenaria and for the first time the link has been established between the gametogenesis cycle and the level of progesterone in this species. The level of progesterone in the gonad of Mya arenaria from Rimouski was 12% of those of levels found in Anse à l'Orignal. Inhibition of synthesis of progesterone by the presence of endocrine disruptors as TBT and DBT in the Rimouski gonad clams may cause the delay in the sexual maturation. When Mya arenaria was exposed to 100 ng TBTCl/L we obtained an accumulation of 491 ng of TBT as Sn/g gonad dry weight for a period of two months and of 1031 ng TBT as Sn/g gonad dry weight after three months of exposure. Mesocosms experiments have shown an increase of testosterone by 50% in August followed by an increase of 17 -estradiol between September and October in female gonads exposed to 10 and 100 ng TBTCl/L in comparison to the controls
Lecarme-Théobold, Émilie. "Comportement du tributylétain en milieu aqueux en présence d'une phase solide hétérogène". Nancy 1, 1998. http://www.theses.fr/1998NAN10255.
Pełny tekst źródłaDangles, Olivier. "La réaction de coupure réductrice des dérivés allyliques par l'hydrure de tributylétain catalysée par un complexe soluble du palladium : utilisation en chimie des groupements protecteurs et application à la synthèse peptidique sur support solide". Paris 11, 1989. http://www.theses.fr/1989PA112121.
Pełny tekst źródłaThe palladium catalyzed nucleophilic substitution of allyl derivatives- the Trost-Tsuji reaction- is viewed here for its leaving group entity. It appears, there-fore, as a deprotection procedure for various functional groups initially protected as their allyl derivatives. Tributyltin hydride, whose hydride donor properties are considerably enhanced in the presence of catalytic amounts of palladium complexes, is the entering nucleophilic species. The hydrostannolytic cleavage of allyl derivatives by palladium catalyst/tributyltin hydride system is highly selective and instantaneous at room temperature. Two applications of this reaction to solid phase peptide synthesis are described: -the deprotection of the amino group of amino-acids and peptides, initially protected by the allyloxycarbonyl group. The reaction has been repeatedly used in the synthesis of the biologically active undecapeptide substance P which was carried out on a classical p-methylbenzhydrylamine resin support, -the cleavage of an allylic resin-peptide link after the assembly of the peptide chain had been carried out under standard conditions (Boc strategy). Such method allows the obtention of free protected peptide fragments which con be later used in convergent synthesis
Bendriaa, Loubna. "Etude et caractérisation de biocapteurs bactériens luminescents pour la détection de molécules et de microorganismes". Le Mans, 2005. http://cyberdoc.univ-lemans.fr/theses/2005/2005LEMA1024.pdf.
Pełny tekst źródłaTessier, Emmanuel. "Etude de la réactivité et du transfert du tributylétain et du mercure dans les environnements aquatiques". Pau, 2004. http://www.theses.fr/2004PAUU3034.
Pełny tekst źródłaAquatic ecosystems are particularly affected by tributyltin (TBT) and mercury (Hg) chronic contamination. These micropollutants are ubiquitous and persistent and occurred at trace level, likely to drastically impair aquatic environments. TBT and Hg biogeochemical cycles are driven by transformation and transfer mechanisms between the different environmental compartments. These natural processes have been studied in details by using novel analytical methods and environmental design to improve the risk assessment. The first part of this work focus on the mechanistic study of TBT and Hg reactivity and transfer in reconstituted aquatic ecosystems. These experiments involve both state-of-the-art analytical speciation techniques, partly based on quantification by isotopic dilution and experimental tools simulating the environmental conditions. Kinetics of TBT and Hg distribution (adsorption, bioaccumulation, biodegradation, clearance) have been simultaneously characterized in al compartments of the microcosms presenting a simple biological organization. In a second step, volatilization kinetics of TBT at real interfaces have been studied to assess the potential remobilization and elimination pathways of butyltin compounds. Finally, in a third part, stable isotopic tracers of Hg have been employed to discriminate and quantify the coupled methylation and demethylation kinetics in estuarine sediments, by forcing different environmental factors (oxygenation, microbial activity)
Yvon, Yan. "Développement d'une méthode de décontamination active des sédiments portuaires pollués en tributylétain par électromigration". Phd thesis, Université de Pau et des Pays de l'Adour, 2008. http://tel.archives-ouvertes.fr/tel-00477602.
Pełny tekst źródłaDesauziers, Valérie. "Dosage du tributylétain dans les sédiments marins : études préliminaires pour l'élaboration d'un matériau de référence international". Pau, 1991. http://www.theses.fr/1991PAUU3016.
Pełny tekst źródła