Dissertations / Theses: 'Metals – Toxicology'

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Chen, Xuehui. "Accumulation of heavy metals and organochlorine pesticides in human milk and adipose tissues, and its health concerns." HKBU Institutional Repository, 2007. http://repository.hkbu.edu.hk/etd_ra/779.

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Intima, Danielle Polidorio. "Avaliação do risco a exposição ocupacional a metais em incineradores de resíduos de serviços de saúde." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/46/46133/tde-23072008-085439/.

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O trabalho teve como objetivo avaliar o risco a exposição ocupacional a metais em incineradores de resíduos de serviços de saúde, com o intuito de verificar as condições de trabalho das usinas de incineração, a fim de proteger a saúde dos trabalhadores do setor e evitar danos ao meio ambiente. Resíduos de serviços de saúde são resíduos sépticos caracterizados como resíduo Classe I por apresentarem patogenicidade, portanto, seu estudo é de extrema importância para a saúde pública e para qualidade do meio ambiente. Um dos processos de tratamento recomendado pela legislação para este tipo de resíduo consiste na incineração. Este processo baseia-se na decomposição térmica via oxidação, com o objetivo de minimizar a toxicidade e o volume dos resíduos. A presença de metais nos resíduos a serem incinerados é uma preocupação, pois este processo provoca a partição do metal presente nos resíduos de alimentação da câmara de combustão, podendo ocorrer sua emissão juntamente com as cinzas, ou com os resíduos do sistema de controle de poluição ou, até mesmo, através da chaminé dependendo de sua volatilidade. Em face desta problemática, faz-se necessária avaliação do risco ocupacional gerado pela exposição ao material particulado e aos gases tóxicos gerados pelo processo. Esta avaliação consiste na caracterização das partículas através da medição de seus constituintes em massa por volume de ar do ambiente de trabalho amostrado. Para isso, foi aplicada metodologia específica e reconhecida do National Institute of Organization Safety Health (NIOSH), o qual recomenda para a amostragem de mercúrio a utilização de resina hopcalite, e para os demais metais a utilização de filtro de éster de celulose. Como técnicas analíticas, este instituto recomenda a utilização da espectrometria de absorção atômica por geração de vapor frio para determinação de mercúrio e da espectrometria de emissão atômica com plasma de argônio induzido para os demais metais. De acordo com os resultados, foram obtidas concentrações acima do limite estabelecido para arsênio, berílio, cádmio, chumbo e mercúrio. Portanto, foram propostas alterações tecnológicas no processo e adequação dos equipamentos de proteção, com o intuito de proteger a saúde dos trabalhadores, da população e evitar danos ao meio ambiente.
This project aimed to evaluate the risk of metal occupational exposition in hospital waste incinerators, in order to verify the incineration plant work conditions, to protect the workers\' health and to avoid damage to the environment. Hospital waste is septic, characterized as Hazardous Waste (Class I) due to its patogenicity, therefore their study is extremely important for public health and environment quality. One of the legally recommended treatment processes to this kind of waste is the incineration. This process is based on thermal decomposition by oxidation, to minimize the toxicity and the waste volume. The presence of metal in the waste to be incinerated is a concern, because this process causes the partition of the metal present in the feeding waste of the combustion camera, which could lead to its emission together with the ash or even with the pollution control system waste, or, even, through the chimney, depending on its volatility. Due to this issue, occupational risk evaluation generated by exposition to particulate material and toxic gases emitted by the process rests necessary. This evaluation consists of particle characterization by measuring the constituents in mass per volume of the environmental sampling air. In order to reach it, specific and recognized methodology from the National Institute of Organization Safety Health (NIOSH) was applied, which recommends for mercury sampling the use of hopcalite resin, and for the other metaIs the use of cellulose filter. As analytic techniques, this institute recommends the use of cold vapor atomic absorption spectrometry to mercury determination and the inductively coupled plasma emission spectrometry to the other metals. According to the results, the obtained concentrations were above the limit established for arsenic, beryllium, cadmium, lead and mercury. Therefore, technological alterations were proposed in the process and adaptation of the protection equipments, in order to protect the employees\' health, the population health and to avoid damage to the environment.

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Ramos, Teresinha Aparecida Dias. "Exposição a metais em pescadores do alto Rio São Francisco, Brasil: um estudo preliminar." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/9/9141/tde-16112017-110000/.

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Em 2006 foi realizado um estudo preliminar para avaliar a exposição a metais em pescadores do Alto São Francisco, no estado de Minas Gerais, Brasil. Os pescadores das cidades de Três Marias, principal foco de pesquisa, e Morada Nova de Minas, como controle, foram avaliados sob o ponto de vista clínico e laboratorial, através de exames bioquímicos e dosagens de Pb-S, Cd-V, As-V, Zn-V e Mn-V. Os resultados das avaliações apresentaram diferenças estatisticamente significativas para o zinco e o arsênio, entre os dois grupos avaliados. Para o chumbo e o manganês, as diferenças não foram, estatisticamente, relevantes. Para o cádmio os dados foram idênticos para ambas populações. Embora os estudos para verificar a contaminação por metais tenham sido feitos, ainda não há evidências de comprometimento da saúde dos pescadores pela contaminação de metais.
A preliminar study to estimate the exposure to metals by fishermen at the High San Francisco River area in Minas Gerais State, in Brazil, had been accomplished in 2006. The fishemen at Tres Marias and Morada Nova county in Minas Gerais State (used a control group), had been evaluated under a clinical and laboratorial point ofview, through a biochemical analysis and Pb-B; Cd -D, As -D, ZnD and Mn-D determinations. The results apparently presented a significant statistical differences related to Zinc and Arsenic among the evaluated fisherman groups. It was not found statistically relevant differences for Manganese and Lead. For urinary Cd, the results were identical at both cities. Although the possibility of exposure by those metals have been studied, there are no evidences of fishermen\'s health implications yet.

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Yu, Lok Chiu. "Cellular metabolism in in vitro toxicity and toxicology studies." HKBU Institutional Repository, 2005. http://repository.hkbu.edu.hk/etd_ra/675.

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Zheng, Wei. "Defense of mammalian body against heavy metal-induced toxicities: Sequestration by the choroid plexus and elimination via the bile." Diss., The University of Arizona, 1991. http://hdl.handle.net/10150/185389.

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Tissue sequestration and biliary elimination are two of the important mechanisms by which mammalian body defends against heavy metal insults. In rats or rabbits that had received Pb, Cd, Hg, As and ²¹⁰Po, these metal ions were sequestered in the choroid plexus at concentrations of Pb, Cd, Hg, As and Po that were 57, 33, 12, 13 and 5 times higher, respectively, than those found in the brain cortex. In addition, the concentrations of these heavy metal ions were many fold greater in the choroid plexus than in the CSF or blood. The accumulation of Pb in the choroid plexus was dose-dependent and time-related. When the choroid plexus was incubated, in vitro, with ouabain, the latter significantly inhibited the uptake of Cd from the CSF side of the choroid plexus. Cystine concentration was four times greater in the choroid plexus than in brain cortex. Results suggest that the choroid plexus sequesters toxic metal and metalloid ions. It appears to do this in order to protect the CSF and brain from toxic heavy metals in the blood. The effect of N-(2,3-dimercaptopropyl) phthalamidic acid (DMPA), meso-dimercaptosuccinic acid (DMSA) and 2,3-dimercapto-1-propane sulfonic acid (DMPS) on biliary excretion of Cd was studied in rat chronic intoxication mode. DMPA (0.10 mmol/kg, iv), when given to rats three days after exposure to Cd, elicited within 30 min a 20-fold increase in biliary Cd excretion. GSH in rat bile was also increased three fold as compared to control. Neither DMSA nor DMPS increased biliary Cd or GSH. Upon iv administration, DMPA, not DMSA, appeared in bile. An altered, presumably disulfide, form of DMPS was also found in bile. Incubation of DMPA or DMSA with Cd-saturated MT resulted in the removal of Cd from MT. DMPS, however, promoted the formation of MT polymers. DMPA protected biliary GSH from autoxidation. Gel filtration and autoradiographic study of rat bile samples showed that the radioactivity of Cd was correlated with both GSH and DMPA. The evidence supports the mechanism that the increase of biliary Cd by DMPA is the result of DMPA entering cells and removing Cd from MT. Protection of GSH autoxidation by DMPA may facilitate Cd elimination via the bile.

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Sekhula, Koena Sinah. "Heavy metal ion resistance and bioremediation capacities of bacterial strains isolated from an Antimony Mine." Thesis, University of Limpopo, 2005. http://hdl.handle.net/10386/139.

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Thesis (M.Sc.) -- University of Limpopo, 2005
Six aerobic bacterial strains [GM 10(1), GM 10 (2), GM 14, GM 15, GM 16 and GM 17] were isolated from an antimony mine in South Africa. Heavy-metal resistance and biosorptive capacities of the isolates were studied. Three of the isolates (GM 15, GM 16 and GM 17) showed different degrees of resistance to antimony and arsenic oxyanions in TYG media. The most resistant isolate GM 16 showed 90 % resistance, followed by GM 17 showing 60 % resistance and GM 15 was least resistant showing 58 % resistance to 80 mM arsenate (AsO4 3-). GM 15 also showed 90 % resistance whereas isolates GM 16 and GM 17 showed 80 % and 45 % resistance respectively to 20 mM antimonate (SbO4 3-). Arsenite (AsO2 -) was the most toxic oxyanion to all the isolates. Media composition influenced the degrees of resistance of the isolates to some divalent metal ions (Zn2+, Ni2+, Co2+, Cu2+ and Cd2+). Higher resistances were found in MH than in TYG media. All the isolates could tolerate up to 5 mM of the divalent metal ions in MH media, but in TYG media, they could only survive at concentrations below 1 mM. Also, from the toxicity studies, high MICs were observed in MH media than TRIS-buffered mineral salt media. Zn2+ was the most tolerated metal by all the isolates while Co2+ was toxic to the isolates. The biosorptive capacities of the isolates were studied in MH medium containing different concentrations of the metal ions, and the residual metal ions were determined using atomic absorption spectroscopy. GM 16 was effective in the removal of Cu2+ and Cd2+ from the contaminated medium. It was capable of removing 65 % of Cu2+ and 48 % of Cd2+ when the initial concentrations were 100 mg/l, whereas GM 15 was found to be effective in the biosorption of Ni2+ from the aqueous solutions. It was capable of removing 44 % of Ni2+ when the initial concentration was 50 mg/l. GM 17 could only remove 20 % of Cu2+ or Cd2+. These observations indicated that GM 16 could be used for bioremediation of xvi Cu2+ and Cd2+ ions from Cu2+ and Cd2+-contaminated aqueous environment, whereas GM 15 could be used for bioremediation of Ni2+.
National Research Foundation and the University of the North Research Unit

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Wilkins, Janine Catherine. "Cadmium tolerance in Holcus lanatus L. : studies of stability and differential cadmium uptake in two ecotypes." Thesis, University of Bristol, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297644.

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Nkqenkqa, Vuyiseka. "Metal and microbial contamination of agricultural soil and the Veldwachters River, Stellenbosch, South Africa." Thesis, Cape Peninsula University of Technology, 2017. http://hdl.handle.net/20.500.11838/2423.

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Thesis (MTech (Environmental Health))--Cape Peninsula University of Technology, 2017.
Surface water is used as a source of water supply in many countries, including South Africa. One of the sources of surface water pollution is leachate and surface runoff from landfills. In agricultural soils, the landfill runoff and leachate deteriorate the quality and affect the fertility of soil. The entry of metals and microorganisms from landfill leachate to adjacent environments is through surface runoff due to rainfall. Adverse effects on human- and environmental health triggers a need to monitor and control contaminants in the environment. The aims of the study are to determine the effect of landfill runoff and leachate on agricultural soil and river water (Veldwachters River) running adjacent to the Devon Valley landfill site and to identify potential metal-tolerant organisms in environmental samples collected in Stellenbosch, Western Cape, South Africa. Samples (agricultural soil, river water and sediments) were collected once a month for a period of six months from the study area for analysis. Physicochemical parameters that are known to have major effects on environmental samples were assessed and the concentrations of various metals (Al, Pb, Cr, Mn, Mo, Co, Ni, Cu, Zn, Fe, Cd and V) were also determined by means of inductively coupled plasma mass spectrometry (ICP-MS). Soil texture analysis was tested in order to monitor the metal distribution in soils under the influence of environmental factors.

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Gausman, Maria M. "A COMPARISON OF DUCKWEED AND STANDARD ALGAL PHYTOTOXICITY TESTS AS INDICATORS OF AQUATIC TOXICOLOGY." Miami University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=miami1153752259.

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Santos, Claudia Regina dos. "Avaliação dos indicadores biológicos de exposição aos metais em trabalhadores de fundições." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/9/9141/tde-13012012-104922/.

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A produção de metais sanitários é um setor em constante fase de crescimento no país. O processo industrial envolve etapas como a evaporação, condensação e oxidação dos metais no ar que levam a formação de fumos metálicos em vários tipos de indústria, inclusive em fundições. A exposição do trabalhador ao ambiente contaminado pode levar ao aparecimento de alterações bioquímicas e, em algumas circunstâncias, de doenças profissionais. No setor de metais sanitários, são utilizadas ligas metálicas de latão, onde predomina o zinco e o cobre, sendo o chumbo, cádmio, manganês e níquel, metais que aparecem sob a forma de impurezas. Desses metais, apenas o chumbo sanguíneo (Pb-S) e o cádmio urinário (Cd-U) são regulamentados no Brasil, de acordo com a NR-7 do Ministério do Trabalho, como indicadores biológicos de exposição. No presente estudo, foram otimizados e validados métodos para a determinação de Pb-S, Cd-U, Mn-U e Ni-U por espectrometria de absorção atômica acoplado a forno de grafite. Posteriormente foram avaliados 273 indivíduos do sexo masculino (178 do grupo exposto e 95 do grupo controle) que trabalhavam em 8 fundições de metais sanitários de Loanda-PR. Os níveis de Pb-S apresentaram-se elevados, considerando o limite internacional. Os metais avaliados na urina Cd-U, Mn-U e Ni-U apresentaram concentrações relativamente baixas, sendo considerado o chumbo como o principal problema, relacionado aos fumos metálicos. Foram propostas medidas corretivas nos ambientes de trabalho e os níveis dos quatro metais em questão foram reavaliados em dois períodos diferentes (antes e após as modificações), apresentando no segundo momento reduções estatisticamente significativas. As médias observadas nos dois períodos foram de 42,74µg/dL e 26,54µg/dL para o Pb-S; 0,269 e 0,015µg/g de creatinina para o Cd-U; 1,94 e 0,39µg/g de creatinina para o Mn-U e 1,82 e 0,68µg/g de creatinina para o Ni-U, com níveis de significância (p) < 0,05, evidenciando assim a importância da adequação do ambiente de trabalho na garantia de exposições seguras para o trabalhador.
The sanitary metal production is a sector in constant development in Brazil. This industrial process involves stages such as evaporation, condensation and oxidation of metals, therefore allowing the formation of metallic fumes in some types of industry, and also in foundries. The contaminated environment can induce, in the workers, biochemical alterations and, in some circumstances, occupational diseases. In the sanitary metal sector, alloys are used in which predominate the metals zinc and copper, being lead, cadmium, manganese and nickel, metals that can be found in the form of impurities. According to Brazilian legislation\'s (Ministry of Work) only lead in blood and cadmium in urine are regulated as biological monitoring of exposure. In the present study, methods based on graphite furnace atomic absorption spectrometry and zeeman background correction were validated for quantification of Pb-B, Cd-U, Mn-U and Ni-U, and 273 male individuais (178 exposed group and 95 non exposed - control group), working in 8 sanitary metal foundries, in Loanda, Paraná, a state located in the south of Brazil, were evaluated. The levels of Pb-B were higher than the international permissible limit. Relatively low concentrations were found for the other evaluated metals: Cd-U, Mn-U and Ni-U, thus lead can be considered, in this case, the main problem, associated with metallic fumes. Corrective measures in the work environment were proposed and implemented, thus the four metais were evaluated in two distinct situations (biological determinations were done before and after the modifications). The results of the second evaluation showed reductions those were statistically significant. The means obtained in the two determinations were 42,74µg/dL and 26,54µg/dL for Pb-B; 0,269 and 0,015µg/g creatinine for Cd-U; 1,94 and 0,39µg/g creatinine for Mn-U and 1,82 and 0,68µg/g creatinine for Ni-U, with leveis of significance (p) < 0,05, thus evidencing the importance of the adequacy of the work environment in the guarantee of safe exposures for the workers.

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Campos, Bruno Galvão de. "Avaliação do risco ecológico de metais em sedimentos da Baía de Guanabara (RJ), através de um método escalonado baseado em múltiplas linhas de evidências /." São Vicente, 2017. http://hdl.handle.net/11449/148708.

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Orientador: Denis Moledo de Souza Abessa
Resumo: A Baía de Guanabara concentra aproximadamente 70% das indústrias do Estado do Rio de Janeiro. Os resíduos produzidos por essas fontes, somados à carga de esgoto doméstico, transformaram a região em umas das áreas mais poluídas da costa Brasileira. O presente estudo realizou a avaliação do risco ecológico dos metais em sedimentos da Baía de Guanabara, por meio de um método escalonado utilizando múltiplas linhas de evidência: caracterização do sedimento quanto à sedimentologia e concentração de metais, comparação das concentrações ambientais com guias de qualidade de sedimento, ensaios de toxicidade crônica utilizando os organismos Anomalocardia brasiliana e Nitocra sp., ensaios de toxicidade aguda utilizando os organismos Tiburonella viscana, Kalliapseudes schubartii, e Anomalocardia brasiliana. Para comprovar existência de relação causa e efeito entre os metais e a toxicidade, foram empregadas a técnica do TIE, análises multivariadas (PCA) e matrizes qualitativas. Os sedimentos mostraram níveis altos a moderados de metais (Zn, Pb, Cu, Cr) associados com a toxicidade. O TIE revelou que, além dos metais, amônia e compostos orgânicos são contaminantes presentes na região que tem a capacidade de causar toxicidade. Desse modo constatou-se que os metais constituem uma importante classe de contaminantes para a Baía de Guanabara, os quais, além de estarem presentes em altas concentrações, interagem com outros contaminantes e são também (co)responsáveis por efeitos biológicos negativos
Abstract: The Guanabara Bay (GB) comprises approximately 70% of the industries of Rio de Janeiro State. The wastes produced by these sources, combined with the domestic sewage loads, have transformed the region into one of the most polluted areas of the Brazilian coast. The present study evaluated the ecological risk of metals in sediments from the GB by the use of a tiered approach. The chosen method combines the following lines of evidence: geochemistry, comparison of environmental concentrations of metals with sediment quality guidelines, chronic sediment toxicity tests with Anomalocardia brasiliana and Nitocra sp.; and acute sediment toxicity tests with Tiburonella viscana, Kalliapseudes schubartii, and Anomalocardia brasiliana. To verify the existence of cause and effect relationships between metals and toxicity, the Toxicity Identification Evaluation (TIE) technique, multivariate analysis (PCA) and qualitative matrices were used. Sediments showed high to moderate levels of metals (Zn, Pb, Cu, Cr) associated with toxicity. In addition, the TIE has revealed that metals, ammonia and organic compounds contribute to cause sediment toxicity. We concluded that metals are an important class of contaminants for the GB, together with other chemicals, as they are present in high concentrations, interact with other substances and are (co)responsible for the negative biological effects
Mestre

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Nightingale, Leigh. "The toxic effect of heavy metals on algal biomass (Spirulina sp.) and carbonic anhydrase activity, an enzyme which is central to algal application in metal precipitation." Thesis, Rhodes University, 2004. http://hdl.handle.net/10962/d1007858.

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Acid rmne drainage (AMD) is a major pollution problem througbout the world, adversely affecting both surface and groundwaters. AMD is principally associated with the mining of sulphide ores. The most commonly associated minerals being sulphur, copper, zinc, silver, gold, lead and uranium. As conventional methods for removing heavy metals from wastewater are often prohibitively expensive, the implementation of biological processes for the removal of heavy metals has become a realistic practice. The objectives of this project was firstly to establish the effect of copper, lead and nickel, heavy metals commonly found in AMD waters, on the enzyme carbonic anhydrase, which is an integral part of the carbon concentrating mechanism (CCM) and secondly, to determine the feasibility of using the alkalinity generated by Spindina for the precipitation of heavy metals from solution. Initially, batch flask experiments were performed and it was found that the algae were able to utilise the bicarbonate supplied in the medium, under CO, limiting conditions, through the induction of their CCM, resulting in the generation of carbonate. The effect of the inhibitors, acetazolamide (AZ) and ethoxyzolamide (EZ), were also investigated in order to determine the importance of carbonic anhydrase (CA) in inorganic carbon accumulation and photosynthesis. Results obtained were consistent with those observed in literature and it was found that at IOOf.LM AZ and EZ, complete inhibition of photosynthesis and carbonic anhydrase occurred, with no oxygen being evolved. The results obtained from the inhibitor experiments substantiate the findings that carbonic anhydrase is an important part of the CCM, and that the dehydration of bicarbonate to carbon dioxide and hydroxide ions, is in fact an enzymatic process regulated by the enzyme carbonic anhydrase and is essential for efficient photosynthesis. The effect of heavy metals on Spirulina was also investigated. Lead, copper and nickel were all found to cause a reduction in the synthesis of chlorophyll a, which resulted in a decrease in photosynthetic efficiency and eventually death of the culture. The morphology of the algae was also severely affected by heavy metals, with degradation and aJmost complete disintegration of the algal filaments occurring. Using the Wilbur-Anderson assay method, carbonic anhydrase activity was found to be lower in the experimental flasks containing heavy metals, than the control flasks, reducing the algae's ability to utilise the bicarbonate in solution for effective photosynthesis. The Wilbur-Anderson assay method did not prove to be a reliable method for measuring changes in enzyme activity as results were found to be erratic. Therefore attempts were made to use an oxygen electrode as an alternative method for determining the effects of various parameters on enzyme activity and photosynthesis, this proved to be more successful. Because of the toxic effects of heavy metals on Spirulina it was decided that the use of the biogenic alkalinity generated by the algae for the precipitation of heavy metals may be successfully employed as an alternative method for bioremediation and metal recovery. Carbonate reacts readily with metals, therefore the carbonate produced by this algal system was used for the precipitation of metals. It was possible to categorise the precipitation reactions observed into three groups, namely those metals which, a) precipitate as hydroxides, b) precipitate as carbonates generated from the dissociation of bicarbonate and c) metals which can only precipitate if there is free carbonate present in solution.

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Ngule, Chrispus M. Jr. "In Vitro Adsorption of Heavy Metals Using Metal-Organic Frameworks." Youngstown State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1597664070125999.

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Bryson, Stuart Edwin. "A Geochemical Characterization of Streams Surrounding the Tom and Jason SEDEX Deposits of the MacMillan Pass, Yukon, Canada: Implications for Mineral Exploration and Toxicology." Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/35781.

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This study presents a geochemical characterization of stream waters draining the sedimentary exhalative (SEDEX) Tom and Jason Pb-Zn deposits and surroundings in the MacMillan Pass, Yukon. Streams sampled have wide ranging pH values of 3 to 8.2. Dissolved metal concentrations vary widely with water source and pH. Of note, streams draining the Tom and Jason deposits are acidic and neutral respectively, which greatly affects metal solubility. The Tom Deposit drainage is extremely high in dissolved and fine sediment fraction lead, as well as dissolved zinc. Neutral streams draining the Jason deposit have less dramatic metal concentrations, but do show elevated dissolved zinc and fine sediment fraction lead concentrations. Modelling using the thermodynamic equilibrium program PHREEQC and XRD analysis indicate that ferricrete hardpans underlying acidic drainages are formed where drainage water is saturated with respect to schwertmannite. Ferrihydrite is formed where the rapid mixing of waters increases the pH rapidly. An aluminium oxy-hydroxide, likely gibbsite, precipitates where pH levels exceed 4.5, however it appears to dissolve with decreasing pH. This study looks at dissolved, suspended and fine fraction sediments to provide a more complete view of metal movement under various conditions which may be useful to both exploration and environmental fields.

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Bryant, Joshua Lee. "Incorporating Ground Beetle (Coleoptera: Carabidae) Assemblage Data and Earthworm Bioassays in the Ecological Risk Assessment of a Trap and Skeet Shooting Range." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1275411039.

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陳慶文 and Hing-man Chan. "An ecotoxicological study of trace metals in the green-lipped mussel Perna viridis (L.) (Bivalvia : Mytilacea)." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1987. http://hub.hku.hk/bib/B3120806X.

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Felix, JoÃo Ermeson Mota. "SÃntese de sÃlica mesoporosa de grande Ãrea superficial para o tratamento de efluentes e sua aÃÃo conjunta com CaCO3 e o extrato aquoso da folha da bananeira contendo taninos." Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=9822.

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Este trabalho consiste na sÃntese de sÃlica mesoporosa de grande Ãrea superficial e seu uso para fins de tratamento de efluentes na remoÃÃo de metais tÃxicos e compostos orgÃnicos, alÃm do seu uso conjunto com CaCO3 e o extrato aquoso das folhas da planta Musa spp (Bananeira) que provavelmente contem taninos. Existem diversos trabalhos sobre a utilizaÃÃo de sÃlica mesoporosa, de taninos vegetais e do carbonato de cÃlcio, que possuem eficiÃncia na remoÃÃo de metais tÃxicos e de compostos orgÃnicos de corpos hÃdricos e efluentes. A sÃlica Ã um polÃmero inorgÃnico de formula mÃnima SiO2, onde muitos estudos utilizando sÃlica mostram sua eficiÃncia na remoÃÃo da grande maioria dos contaminantes das Ãguas por adsorÃÃo e/ou precipitaÃÃo, sendo esses contaminantes orgÃnicos ou inorgÃnicos e a sÃlica ainda podendo ser utilizada diversas vezes apÃs sua purificaÃÃo. Os taninos sÃo polihidroxifenois de origem vegetal (com massa entre 500 e 3000 g/mol) e os CaCO3 Ã um minÃrio com os mais diversos usos. Assim como os taninos, a utilizaÃÃo de carbonato de cÃlcio para o tratamento de efluentes jÃ se mostrou ser um mÃtodo simples e eficiente. Como amostragem para os testes de remoÃÃo de metais utilizando os compostos isoladamente e depois em conjunto foi utilizada uma soluÃÃo padrÃo dos sais de metais tÃxicos do 1Â e do 3Â grupos analÃticos, contendo aos metais de transiÃÃo da tabela periÃdica e o Al3+, que sÃo os grupos analÃticos de concentraÃÃo conhecida (1Â grupo: Ag+, Pb2+, Hg22+; 3Â grupos: Al3+, Cr2+, Fe2+, Mn2+, Zn2+, Co2+ e Ni2+); onde foram feitos os testes de eficiÃncia e as adiÃÃes dos compostos para retirada dos contaminantes. Ambos os testes de eficiÃncia e de adiÃÃo mostraram retirar boa parte de micro poluentes orgÃnicos e inorgÃnicos, sendo a concentraÃÃo de compostos orgÃnicos medidos pela DQO diminuÃdos a nÃveis abaixo de 5 mg/L e metais como Al3+, Fe2+ e Pb2+ foram removidos da soluÃÃo com eficiÃncia de 95% em relaÃÃo a concentraÃÃo inicial.
This work consists in the synthesis of mesoporous silica of high surface area and its use for wastewater treatment in the removal of toxic metals and organic compounds, and their use together with CaCO3 and aqueous extract of the leaves of the plant Musa spp (Banana) that probably contains tannins. There are several studies on the use of mesoporous silica, vegetable tannin and calcium carbonate, which have efficiency in the removal of toxic metals and organic compounds of bodies of water and wastewater. Silica is an inorganic polymer of formula minimum SiO2, with many studies using silica show its efficiency in removing the majority of contaminants from water by adsorption and / or precipitation with organic or inorganic contaminants such and the silica may still be used several times after its purification. The tannins are polihidroxifenois of plant origin (with mass between 500 and 3000 g / mol) and CaCO3 is a mineral with many uses. As tannins, the use of calcium carbonate to sewage treatment has proved to be a simple and efficient method. As a sample for testing for metal removal using the compounds separately and then together we used a standard solution of the salts of toxic metals of the 1st and 3rd groups analytical containing the transition metals of the periodic table and Al3+, which groups are Analytical known concentration (1st group: Ag+, Pb2+ HG22+; 3rd group: Al3+, Cr2+, Fe2+, Mn2+, Zn2+, Co2+ and Ni2+), where the tests were done and efficiency additions of compounds to remove the contaminants. Both tests of efficiency and plus shown remove much of micro organic and inorganic pollutants, and the concentration of organic compounds measured by COD reduced to levels below 5 mg / l and metals such as Al3+, Fe2+ and Pb2+ were removed from the solution 95% efficiency compared to the initial concentration.

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Chapman, Kimberly K., Phillip R. Scheuerman, G. Lanza, D. Nelson, and R. Brinkhurst. "Comparative Study of Three Oligochaete Species as Indicators of Metals in a Sediment Toxicity Bioassay." Digital Commons @ East Tennessee State University, 1995. https://dc.etsu.edu/etsu-works/2905.

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19

O'Malley, Kristen Marie. "Comparative sensitivity of the early life history stages of the Blue Crab, callinectes sapidus, to mercury exposure." Thesis, Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/25200.

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20

Fung, Chi-tuen, and 馮志端. "Approaches to assess heavy metal toxicity in the marine environment." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B45013378.

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21

Yellowhair, Monica. "The Chemical-Induced Genotoxicity of Depleted Uranium." Diss., The University of Arizona, 2011. http://hdl.handle.net/10150/202509.

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Uranium has been mined for many years and used for fuel for nuclear reactors and materials for atomic weapons, ammunition, and armor. While the radioactivity associated with uranium mining has been linked to the development of lung and kidney cancers, and leukemia, little is known about the direct chemical genotoxicity of uranium. The overall hypothesis of the current research is that uranium can produce DNA damage by chemical genotoxicity mechanisms. Three specific aims were tested. In Aim 1, specific DNA lesions caused by direct interaction of uranium and DNA were investigated. Chinese Hamster Ovary cells (CHO) with mutations in various DNA repair pathways were exposed to 0 – 300 μM of soluble depleted uranium (DU) as uranyl acetate (UA) for 0 – 48 hr. Results indicate that UA readily enters CHO cells, with the highest concentration localizing in the nucleus. Clonogenics assay shows that UA is cytotoxic in each cell line with the greatest cytotoxicity in the base excision repair deficient EM9 cells and the nuclear excision repair deficient UV5 cells compared to the non-homologous end joining deficient V3.3 cells and the parental AA8 cells after 48 hr. This indicates that UA is forming DNA adducts that may be producing single strand breaks through hydrolysis rather than double strand breaks in CHO cells. Fast Micromethod® results indicate an increased amount of single strand breaks in the EM9 cells after 48 hr UA exposure compared to the V3.3 and AA8 cells. In Aim 2, the role of oxidative stress in producing DNA lesions was determined. Cellular oxidative stress has been implicated in the genotoxicity of many heavy metals as a mechanism of induced DNA damage. To investigate this possible mechanism, human bronchial epithelial cells (16HBE14o⁻) were exposed to 30 ppb (0.13 μM U) UA for 2 – 24 hr. UA did not significantly induce oxidative stress compared to untreated cells at 3 – 4 hr time points. These results suggest that cellular oxidative stress is not a major pathway of DU genotoxicity at low concentrations. In Aim 3, DNA damage response to uranium-induced DNA damage was investigated. It has been widely reported that metals can be genotoxic by inhibiting DNA repair. Cultured cells were co-exposed to 0.13 μM UA in the presence of 0 – 25 μM of etoposide for 0 – 48 hr. Results indicate that UA inhibited double strand break repair. Coexposures of etoposide and UA synergistically induced cytotoxicity compared to individual treatments and untreated cells. Co-exposed UA and etoposide treated 16HBE14o⁻ cells exhibited a decrease in phosphorylation of DNA repair proteins compared to etoposide treatments. Untreated and UA-treated 16HBE14o⁻ cells did not induce phosphorylation of DNA repair proteins. These results suggest that DU inhibits double strand break DNA repair at low concentrations in the presence of a known DNA double-strand damaging agent, etoposide. The inhibition of DNA repair by DU at environmentally relevant concentrations suggests a novel means by which uranium may exert its genotoxic effects. Results found at low dose exposures are not consistent with alterations seen with radioactivity, suggesting that the effects of uranium at low doses are due to its chemical genotoxic effects. Understanding how uranium reacts with DNA is important to better understand how this suspected carcinogen induces cancer and to help to elucidate mechanisms that produce cancers in people exposed to uranium.

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Paul, Jenny Sueanna. "ECOLOGICAL AND SOCIOLOGICAL IMPLICATIONS OF TISZA RIVER MINE TAILINGS POLLUTION AND EFFECT OF CHRONIC CADMIUM EXPOSURE ON FISH PHYSIOLOGY." OpenSIUC, 2017. https://opensiuc.lib.siu.edu/dissertations/1450.

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Metals are ubiquitous and naturally occurring; however, anthropogenic activities have elevated metal concentrations in river sediments above what would be expected naturally. One of the primary anthropogenic sources of metals in freshwater is contamination by mine tailings, a toxic slurry of waste rock and chemicals left over after ore minerals or coal extraction. Mining waste is most often stored in retention ponds, which sometimes leak or fail. One of the worst mine tailings disasters on record occurred on the Tisza River of Central Europe in the winter of 2000, releasing over 240,000 tons of mine tailings laced with metals into the natural environment. Elevated metals in freshwater can negatively affect fish and other aquatic organisms, raising concerns as to the long-term ecological consequences of the spill. Therefore, the objectives of this dissertation were to describe the ecological implications of metals pollution from mining on freshwater systems through an empirical case study of the Tisza River combined with controlled laboratory experiments of chronic cadmium exposure on a model species, channel catfish (Ictalurus punctatus). Specific research questions discussed in the following chapters include: (1.) What is the current distribution of metals in the lower Tisza River Basin and are metals transported from the main channel to floodplain habitats?; (2.) Is there evidence for bioaccumulation and/or trophic transfer of metals to fish in the Tisza?; (3.) What are angler’s perceptions and fish consumption risks in the lower Tisza river basin?; and (4.) What are the effects of sub-lethal exposure to cadmium on growth, development, metabolism, and stress response in a model fish species? The case study of the Tisza River Basin was conducted during early summer in 2013 and 2014. Water, sediment, and fish were collected from the Tisza River as well oxbow lakes along the lower basin. Samples were screened for metals via GF-AAS following standard methods. Additionally, we conducted interviews at each sampling location to determine fish consumption habits. Controlled laboratory exposures were conducted during summer of 2015. Eggs of channel catfish (Ictalurus punctatus) were fertilized in treatment water and raised to 6 month old fingerlings. Treatments of cadmium included concentrations of 0.5 µg L-1 (control), 2 L-1 (low) and 6 L-1 (high), with endpoints of growth, development, cellular stress, metabolism, and general stress response. Results indicate that lakes with the greatest connectivity trended toward elevated metals; however, chlorophyll a concentrations decreased suggesting dilution of nutrients from surrounding agriculture. River connectivity therefore increases ecosystem health of floodplain lakes by ameliorating eutrophication, but as a trade-off with potential contamination of metals. This may have implications for management strategies in the basin as fish from the oxbow lakes also trended toward higher concentrations of metals compared to the river main stem. Although we did not detect any indication that metals are biomagnifying through the fish community, fish are clearly taking up contaminants from the water and sediment. Additionally, although fish fillets generally fell below human consumption guidelines, surveys collected at field sites indicate disparities between health risks and perceptions of those risks. For example, many people believe that fish from the oxbow lakes present a lower risk for metals than the river main stem, converse to our findings. Exposure of channel catfish to cadmium concentrations similar to those observed in the Tisza Basin indicate that negative physiological effects, such as altered carbohydrate metabolism and subsequently growth, can occur in fish at muscle concentrations below consumption guidelines. Although cadmium in Tisza fish fillets were lower than expected, metals may still be problematic for the basin as they may disproportionately affect early life stages of fish. This could skew life histories of exposed populations compared to unaffected fish, potentially reducing growth rates, size at maturity, reproductive output, and lifespan; indicating the need for more paired field and laboratory assessments of chronic metals exposure.

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Brossi, Maria Julia de Lima. "Ecotoxicologia de um sistema florestal de eucalipto tratado com lodo de esgoto." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/64/64135/tde-29112009-162251/.

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A aplicação do lodo de esgoto em sistemas florestais busca o aprimoramento da produção, favorecendo as características físicas, químicas e biológicas do solo e das plantas. Entretanto, o lodo pode conter patógenos e, elementos orgânicos e inorgânicos tóxicos, e o efeito destes contaminantes no solo e na planta ainda é pouco conhecido. Sendo assim, foi estabelecida a hipótese de que o lodo de esgoto, quando aplicado ao solo, com base na norma P 4.230, da CETESB, não causa efeitos tóxicos ao sistema solo-eucalipto. Com o objetivo de testar a hipótese acima, foi proposta a determinação da concentração dos elementos potencialmente tóxicos, a avaliação da toxicidade e genotoxicidade do solo tratado com lodo de esgoto e a verificação da correlação entre essas variáveis. O experimento de campo foi instalado em dezembro de 2004, quando mudas de Eucalyptus grandis foram plantadas e tratadas com lodo de esgoto, nas doses de 0; 7,7; 15,4 e 23,1 tha-1, base seca, em área comercial de cultivo de eucalipto da companhia Suzano Bahia Sul Papel e Celulose S.A., em Itatinga, SP. Amostras de solo foram coletadas aos 18, 21, 24, 27 e 34 meses após a aplicação do lodo. Foram determinadas as concentrações de Cr, Mn, Fe, Ni, Cu, Zn, Cd e Pb no solo, extraídos por DTPA, Mehlich-1 e com HNO3+HCl, e quantificados por ICP-MS. A toxicidade do solo foi avaliada por meio dos testes com Daphnia magna (concentração letal-CL50), com Pseudokcrichirella subcaptata (inibição de crescimento-CI50), com Lactuca sativa (crescimento de raiz) e com Allium cepa (índice mitótico, aberrações cromossômicas e micronúcleos). Os resultados mostraram um aumento nos teores de Cr, Mn, Fe, Ni, Cu, Zn, Cd e Pb no solo de acordo com as doses. Foi observado um aumento da toxicidade para D.magna, P.subcaptata e genotoxicidade e mutagenicidade para A. cepa de acordo com as doses. O lodo de esgoto aplicado ao solo na dose de 15,1 t ha-1, recomendada pela norma da CETESB, não causa efeito tóxico, genotóxico ou mutagênico no sistema solo-planta, de acordo com os testes realizados. Há correlação entre os testes de toxicidade com P. subcaptata, de mutagênicidade com A. cepa (micronúcleos), com os teores dos elementos potencialmente tóxicos no solo. O teste com D. magna constitui uma importante ferramenta na avaliação toxicológica do lodo aplicado ao solo, apesar de não se correlacionar com os teores de elementos potencialmente tóxicos no solo, indicando que a toxicidade do lodo pode estar relacionada também a outros compostos orgânicos tóxicos e/ou agentes patógenos.O teste de toxicidade com L.sativa é inadequado na avaliação toxicológica da aplicação de lodo em relação as doses, por refletir efeitos dos nutrientes e não dos componentes tóxicos do lodo, porém reflete a toxicidade de acordo com o tempo de aplicação do resíduo
The application of sewage sludge in forest systems quests the improvement of the production, favoring the physical, chemistries and biological characteristics of the soil and of the plants. However, the sludge can contain pathogen and, organic and inorganic toxics elements, and the effect of these pollutants in the soil and in the plant is still unknown. It was established the hypothesis that the sewage sludge, when applied to the soil, according to the norm P4.230 of CETESB, doesn\'t cause toxics effects to the soil-eucalyptus system. To test the hypothesis above, it was established as objective, the determination of the concentration of the potentially toxics elements, the evaluation of the toxicity and genotoxicity of the sewage sludge treated soil, and the verification of the correlation among those variables. The field experiment was conducted in December of 2004, when seedlings of Eucalyptus grandis were planted and treated with sewage sludge, in the doses of 0; 7,7; 15,4 and 23,1 tha 1, dry base, in commercial area of eucalyptus cultivation of the Suzano Bahia Sul Papel and Celulose S.A company, in Itatinga, SP. Soil samples were collected to the 18, 21, 24, 27 and 34 months after the application of the sludge. They were established the concentrations of Cr, Mn, Fe, Ni, Cu, Zn, Cd and Pb in the soil, extracted for DTPA, Mehlich-1 and with concentrated HNO3+HCl, and quantified by ICP-MS. The toxicity of the soil was evaluated through the tests with D. magna (lethal concentration -LC50), with Pseudokcrichirella subcaptata (growth inhibition - IC50), with Lactuca sativa (root growth) and with Allium cepa (mitotic index, cromossomic aberration and micronucleus). The results showed an increase in the concentrations of Cr, Mn, Fe, Ni, Cu, Zn, Cd and Pb in the soil in agreement with the doses. An increase of the toxicity was observed for D. magna, P. subcaptata and an increase of the genotoxicity and mutagenicity for A. cepa in agreement with the doses. The applied sewage sludge to the soil in the dose of 15,1t ha-1, recommended by CETESB, doesn\'t cause toxic, genotoxic or mutagenic effect in the system soilplant, in agreement with the accomplished tests. There is correlation among the toxicity tests with P. subcaptata, of mutagenicity with A. cepa (micronucleus) with the concentrations of Cr, Mn, Fe, Ni, Cu, Zn, Cd and Pb in the soil. The test with D. magna is an important tool in the toxicological evaluation of the sludge applied to the soil, however it wasnt correlated with the concentration of potentially toxics elements in the soil, indicating that the toxicity of the sludge can also be related to the other toxic organic compound or pathogen agents. The L.sativa toxicity test is inadequate in the toxicological evaluation of the sludge application, according to the doses, for reflecting effects of the nutrients and it doesnt reflect the toxic components of the sludge, however it reflects the toxicity in agreement with the time of residue application

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Monahan, Jennifer L. "Skeletal Pathology of Tibiotarsi in Chick Embryos Exposed to Platinum Group Metals by Micro-Raman Spectroscopy." Wright State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=wright1278554763.

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25

Arnolds, Judith Lize. "Oxidative stress responses in the aquatic macrophyte, Ceratophyllum Demersum L., as biomarkers of metal exposure." Thesis, Cape Peninsula University of Technology, 2017. http://hdl.handle.net/20.500.11838/2649.

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Thesis (DTech (Environmental Health))--Cape Peninsula University of Technology, 2017.
Metal pollution in aquatic environments is considered a major environmental concern because of variation in several abiotic factors that impose severe restrictions on organisms living in these areas. Ceratophyllum demersum L. (family Ceratophyllaceae), a hornwort or coontail, free floating rootless macrophyte has been suggested a suitable model for investigating metal stress and was used in the current study. This study assessed the use of selected biological responses, namely antioxidant responses and changes in chlorophyll concentration in Ceratophyllum demersum L., as biomarkers of metal exposure, and also investigated the field application of these responses in the Diep River. The ultimate aim was also to determine the usefulness of C. demersum as model of metal contamination and as phytoremediator after a pollution event. An investigation of metal bioaccumulation in this macrophyte exposed to different concentrations of a combination of metals over a five-week exposure period in a greenhouse, was undertaken, as well as a field study in the Diep River, Milnerton, Cape Town and a pond (reference site) at the Cape Peninsula University of Technology, Cape Town, to validate experimental results. In the laboratory study the water was contaminated once off at the beginning of the study, to simulate a pollution event. The metal concentrations in the water and plants were measured in the four treatments and the control every week over a five-week exposure period. The samples were acid-digested and analysed with an Inductively-Coupled Plasma-Mass Spectrophotometer (ICP-MS). The results showed that concentrations of the metals in the water varied in all treatments over time with no specific patterns amongst the treatment groups. This macrophyte proved highly effective in the bioaccumulation of these metals at all four exposure concentrations. The metals bioaccumulated rapidly in the plants after the water was spiked. The main focus of the study was to investigate the possible use of biochemical responses in C. demersum as possible biomarkers for metal exposure. A range of antioxidant/oxidative stress parameters were measured in the plant exposed to a combination of metals (Al, Cu, Fe, Zn) in four different treatments over the five week exposure period. Total antioxidant capacity (TAC) was measured using Total Polyphenols (TP), Ferric Reducing Antioxidant Power (FRAP) and Oxygen Radical Absorbance Capacity assay (ORAC), enzyme activity was determined using Catalase (CAT), Superoxide Dismutase (SOD), Ascorbate Acid (AsA) and Total Glutathione (GSHt) and lipid peroxidation was measured by using Thiobarbituric Acid Reactive Substances (TBARS) and Conjugated Dienes (CDs). The cocktail of the four metals induced significant changes in the antioxidant defence system of C. demersum, including the antioxidant enzyme activities. The different metal exposures disturbed the cellular redox status in the plant. The current study has demonstrated that this macrophyte shows tolerance to metal-induced oxidative stress and that it can survive under relatively high concentrations of these metals by adapting its antioxidant defence strategies. Chlorophyll was extracted in 80% chilled acetone in the dark and the absorbance values were determined using a spectrophotometer. Chlorophyll a (chl a), chlorophyll b (chl b) and total chlorophyll (chl t) contents were measured under different exposure concentrations of metals in the macrophyte. The results of this study indicated that chlorophyll contents were variable over the exposure period and no significant differences in chlorophyll concentrations were found between weeks. A field study in the Diep River and the pond located at the CPUT campus (reference site) was conducted to validate experimental results. Plants in a polluted section of the Diep River were shown to bioaccumulate metals to high concentrations. Bioaccumulation of metals in C. demersum might have induced oxidative stress, and other environmental factors such as temperature- and chemical stress might have caused chlorophyll degradation. The chlorophyll concentrations in the plants of the pond (reference site) might also have been affected by temperature and chemical stress of the water. Significantly higher AsA, CAT, ORAC, SOD and TBARS concentrations in the Diep River plants might be an indication that the plants in the river might be well adapted to the constant exposure to metals and that the plants might have developed a tolerance mechanism to cope with oxidative stress compared to those of the pond. The results show that metals are bioaccumulated quickly by C. demersum after the water is contaminated with metals, i.e. after the "pollution event". However, over time, metals are continuously exchanged between the plants and the water, accounting for the fluctuations in metal concentrations observed over time. This study has shown that C. demersum has phytoremediation potential because it was able to remove high concentrations of metals from the contaminated water. Therefore, C. demersum, can be applied as a model for metal contamination and a phytoremediator after a pollution event. The potential to antioxidant responses and chlorophyll content as biomarkers of metal exposure in C. demersum have been demonstrated.

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Gómez, Ramírez Pilar. "El Búho real (Bubo bubo) como especie biomonitora de contaminantes ambientales persistentes en el Sureste de España." Doctoral thesis, Universidad de Murcia, 2011. http://hdl.handle.net/10803/52186.

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Los estudios de biomonitorización con aves rapaces permiten evaluar el grado de contaminación ambiental y las consecuencias sobre la salud humana y ambiental. Los niveles de metales e insecticidas organoclorados en sangre de pollos de Búho real del sureste de España fueron en general bajos, siendo los niveles de plomo significativamente superiores en los individuos nacidos en una antigua zona minera. La enzima δ-ALAD es un biomarcador sensible de exposición y efecto a plomo en esta especie. El estudio de organoclorados y PBDEs en huevos no eclosionados sugiere cambios en la dieta o posibles focos de contaminación en la zona. El grosor de cáscara de huevo disminuyó conforme aumentaron las concentraciones de p,p’-DDE, alcanzando un porcentaje de disminución relacionada con declives poblacionales en aves a niveles de DDE superiores a 100 ng/g de peso de lípidos. El desarrollo de una nueva técnica permitió detectar residuos de rodenticidas en el 83% de las muestras de hígado.
Biomonitoring studies with raptor birds can be used to evaluate environmental pollution and consequencies to human and environmental health. Levels of metals and insecticides in blood of eagle owl chicks from Southeastern Spain were in general low, being lead levels significantly higher in individuals born in an ancient mining area. The enzime δ-ALAD is a sensitive biomarker of exposure and effect to lead in this species. The study of organochlorine and PBDEs in unhatched eggs suggests dietary shifts or pollutant sources. Eggshell thickness decreased with increasing p,p’-DDE, reaching a level related to population declines in birds when DDE levels exceded 100 ng/g lipid weight. The development of a new tecnique permited the detection of rodenticide residues in 83% of the liver samples.

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27

Santos, Paulo Roberto dos. "Compostos de coordenação do ácido valproico e metais de transição como medicamentos." reponame:Repositório Institucional da UCS, 2014. https://repositorio.ucs.br/handle/11338/879.

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O ácido valproico (AVP) é um fármaco de primeira linha no tratamento de convulsões parciais e generalizadas, porém os efeitos colaterais decorrentes das altas doses administradas produzem danos hepáticos por metabolização. O AVP apresenta alta afinidade com metais de transição e produz compostos de coordenação quimicamente estáveis. O presente estudo teve como objetivos sintetizar quatro complexos de AVP com Cu+2 e Zn+2 ligados com diiminas aromáticas 1,10-fenantrolina (Phen) e 2,2’-bipiridina (Bipy), determinar as estruturas químicas por espectrofotometria de absorção atômica (FAAS), espectrofotometria de infravermelho com transformada de Fourier (FTIR), espectrometria de massas de alta resolução (ESI-TOF-MS), e espectrometria de ressonância magnética nuclear (1H RMN e 13C RMN), avaliar as atividades antioxidantes por ensaios de Sod-like e Cat-like e determinar a citotoxicidade aguda frente à Artemia salina e à cultura celular CHO. O processo de síntese iniciou-se com a preparação dos compostos precursores Cu2(Valp)4 (1) e Zn2(Valp)4 (2) pela reação do valproato de sódio com os sais CuCl2 e ZnCl2 em meio aquoso. As estruturas químicas foram confirmadas por Ponto de Fusão, FAAS, FTIR, 1H RMN e 13C RMN. Os compostos de coordenação Cu(Valp)2(1,10-Phen) (3), Cu(Valp)2(2,2-Bipy).H2O (4), Zn(Valp)2(1,10-Phen).H2O (5) e Zn(Valp)2(2,2-Bipy).H2O (6) (inédito) foram sintetizados pela reação equimolar dos compostos 1 e 2 com os respectivos ligantes neutros 1,10- fenantrolina e 2,2-bipiridina em solvente DMF. Os dados das estruturas químicas dos compostos 3 e 4 foram obtidos por PF, UV-Vis, FAAS, FTIR e ESI TOF-MS e confirmados por comparação com dados da literatura. Os compostos 5 e 6 (inédito) foram analisados por PF, UV-Vis, FAAS, FTIR, ESI TOF-MS, 1H RMN e 13C RMN, e suas estruturas químicas foram confirmadas por comparação com a literatura (5) e por interpretação de espectros (6). O experimento de Sod-like para os compostos 3, 4, 5 e 6 não expressou atividade aparente para a metodologia utilizada, porém todos expressaram atividade de Cat-like. O experimento de citotoxidade aguda frente à A. salina indicou haver correlação dose/resposta para as diferentes concentrações testadas dos compostos 3, 4, 5 e 6 e para os controles 1,10-Phen, 2,2-Bipy e K2Cr2O7. O composto 3 mostrou-se o mais tóxico (CL50: 2 μg mL-1), seguido do composto 5 (CL50: 78 μg mL-1), composto 4 (CL50: 386 μg mL-1) e o composto 6 menos tóxico (CL50: 409 μg mL-1). Os resultados indicam haver maior toxicidade dos compostos com cobre, caso similar observado para os compostos com 1,10-Phen. Os experimentos de citotoxicidade aguda dos compostos 5 e 6 frente à linhagem celular CHO com 24 horas de exposição nas concentrações de 25, 20, 15, 10, 5 e 2 μg mL-1 não expressaram toxicidade para a metodologia utilizada. Os resultados corroboram com aqueles obtidos no ensaio de A. salina.
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Valproic acid (VPA) is a first-line drug in the treatment of seizures in general, but the side effects from high doses produce liver damage by metabolism. VPA has high affinity for transition metals and produces chemically stable coordination compounds. The present study aimed to synthesize four complexes VPA with Cu+2 and Zn+2 with 1,10- phenanthroline and 2,2’-bipyridine linked aromatic diimines, determine the chemical structures by FAAS, FTIR, ESI-TOF MS , 1H NMR and 13C NMR, evaluate the antioxidant activities by Sod-like and Cat-like and determine acute cytotoxicity front of Artemia salina (brine shrimp) and CHO cell culture. The synthesis procedure began with the preparation of precursor compounds Cu2(Valp)4 (1) and Zn2(Valp)4 (2) by the reaction of Sodium Valproate with chlorides of metals in aqueous medium. The chemical structures were confirmed by MP, FAAS, FTIR, 1H NMR and 13C NMR. Coordination compounds Cu(Valp)2(1,10-Phen) (3) Cu(Valp)2(2,2- Bipy).H2O (4), Zn(Valp)2(1,10-Phen).H2O (5) and Zn(Valp)2(2,2-Bipy).H2O (6) (unpublished) were synthesized by equimolar reaction of compounds 1 and 2 with the corresponding neutral ligands 1,10-phenanthroline and 2.2-bipyridine in DMF solvent. The data of chemical structures of compounds 3 and 4 were obtained by MP, UV-Vis, FAAS, FTIR and ESI-TOF MS and confirmed by comparison with the literature data. Compounds 5 and 6 (unpublished) were analyzed for MP, UV-Vis, FAAS, FTIR, ESI TOF-MS, 1H NMR and 13C NMR, and their chemical structures were confirmed by comparison with the literature (5) and interpretation spectra (6). The Sod-like experiments for compounds 3, 4, 5 and 6 were not significant, but all showed activity of Cat-like. The experiment of acute cytotoxicity in A. saline showed significant for compounds 3, 4, 5 and 6 in 8 different concentrations tested results. Compound 3 was found to be the most toxic (LC50: 2 mg mL-1), followed by compound 5 (LC50: 78 mg mL-1), compound 4 (LC50: 386 mg mL-1) and less toxic compound 6 (LC50: 409 mg mL-1). It can be observed correlation affix the higher toxicity of the compounds with copper, the case that observed for similar compounds with 1,10-Phen. The experiments of acute cytotoxicity of compounds 5 and 6 against CHO cell lines after 24 hours of exposure at concentrations of 25, 20, 15, 10, 5 and 2 μg mL-1 showed no significant differences in toxicities to controls. The results corroborate the results obtained using the A. salina.

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Chen, Xunwen. "Expressions of transporters of arsenite and phosphate in rice (Oryza sativa L.) associated with arbuscular mycorrhizal fungi." HKBU Institutional Repository, 2012. https://repository.hkbu.edu.hk/etd_ra/1464.

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Wong, Nga Cheung. "Effects of algae (Isochrysis galbana) and humic acids on copper toxicity to polychaete (Hydroides elegans) larvae." HKBU Institutional Repository, 2005. http://repository.hkbu.edu.hk/etd_ra/665.

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30

Wu, Chuan. "Effects of radial oxygen loss (ROL) on arsenic tolerance, uptake and distribution by rice (Oryza sativa L.)." HKBU Institutional Repository, 2011. http://repository.hkbu.edu.hk/etd_ra/1246.

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31

Hunnestad, Annie Vera. "The Effects of Macronutrient Enrichments (ammonium) on the Distribution of Four Bioactive Trace Metals (Cd, Mo, Ni, Cu) in Seawater and Planktonic Biomass." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for kjemi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-18370.

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Environmental impacts of aquaculture can be widespread and serious, and one of the problems connected to this activity is the release of waste in the form of macronutrients. One important aspect is the potential of a shift in the available nitrogen form from nitrate to ammonium. This has the potential of causing harmful algal blooms, and changing the composition of pelagic microbial communities. Because trace metals are linked to enzymatic transformations of nitrogen it can be expected that a shift in the available nitrogen form to also change the cycling of trace metals in the water column and the microbial uptake. This work presented in this thesis has been part of the large collaborative WAFOW project, and was carried out at the Huinay Scientific Field Station in the Comau Fjord (Northern Patagonian region of Chile). The experiment was designed to follow changes in different variables as a gradient of ammonium was added to different bodies of water (mesocosms). Two types of water were studied (surface and ~10 m depth), and five treatments with increasing ammonium flux were carried out for each water type. In this thesis the variations in the distribution of four different trace metals (Cd, Mo, Ni and Cu) with an increasing ammonium flux has been studied. Samples were analyzed for chelex labile and DGT labile forms of the metals, as well for metal concentration in different size fractions of particles. The enrichment by ammonium caused a bloom in biomass, and caused changes in the distribution of all four metals studied. Most of the metals showed decreasing chelex labile and DGT labile concentration with rising ammonium concentration. For cadmium there was a marked increased uptake per g carbon up to a certain point of ammonium enrichment, and a marked decreased uptake per g carbon when very high amounts of ammonium were added. This suggests that the very high ammonium enrichment scenario somehow has had an inhibiting effect on phytoplankton cadmium uptake. For molybdenum there was a decreasing uptake per g carbon with increasing ammonium flux. This is probably caused by a decreased need for molybdenum in enzymatic transformations of nitrogen when ammonium is supplied in place of nitrate.

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Slabber, Michelle Yvonne. "Accumulation and toxicity of metals in oysters (Striostrea margaritacea) from the South African South Coast." Thesis, Cape Peninsula University of Technology, 2013. http://hdl.handle.net/20.500.11838/2037.

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Thesis submitted in fulfilment of the requirements for the MTech: Oceanography in the Faculty of Applied Sciences at the CAPE PENINSULA UNIVERSITY OF TECHNOLOGY, 2013
The current status of metal pollution off the South African South coast is not well known. This study was the first to be undertaken in many years using Striostrea margaritacea as a subject species. The aims of the study were to determine the degree of metal contamination in the water, sediments, oyster tissues and oyster shells at sites selected in Witsand, Wilderness and Goukamma, as well as to establish if Striostrea margaritacea qualifies as a successful biomonitor when using lysosomal destabilization as a tool. Seasonal variations between sites were also considered. Other objectives, such as the potential of a Marine Protected Area (MPA) as a control site and the necessity of a monitoring program along the south coast were also included. Sites were sampled seasonally for one year at spring low tides. Ten oysters were collected from each individual site upon each visit. The Neutral Red Retention Time (NRRT) assay was used to determine lysosomal membrane integrity of oyster haemocytes, whereafter oysters were sacrificed for metal analyses. Metals that were analysed are aluminium (Al), copper (Cu), zinc (Zn) and iron (Fe). Metal analyses were done using an Inductively Coupled Plasma - Atomic Emission Spectrometer (ICP- AES). All statistical analyses were performed using ANOVA on Ranks to determine if there were significant differences between sites and between sampling occasions. Aluminium concentrations found in the water column at all sites were considered as low. Iron, zinc and copper concentrations within the water column can on the other hand be considered as high when comparisons are drawn with other studies and data sets. Sediment concentrations for all the metals within the present study were considered to be low when compared to other studies and guidelines. There were not many significant differences recorded between sites and no seasonal patterns were present. Within the tissues of the oysters, the metal ranges are considered to be low when compared to other studies. No definite conclusion about the contamination status of the oyster tissue could be drawn due to the lack of comparative literature. A field study in conjunction with a laboratory experiment should yield more reliable results. There were also no seasonal trends present and very few differences between sites. The bioaccumulation factors were considered as being low with a few exceptions where they were moderate when oyster tissue data was compared to water and sediment data. Concentrations for Al, Zn and Cu in the shells could be considered low when comparisons are drawn, with the exception of Fe that was found to be high. The bioaccumulation factors were considered to be low when oyster shell concentrations were compared to water and sediment data. There were also no seasonal trends present and a prolonged sampling period is suggested to further investigate these findings. When a comparison was drawn between the tissue and shell data a clear pattern was evident. Al and Fe concentrations were highest within the shell where as Zn and Cu concentrations were highest within the tissues of the animal. The theory of mineralization is supported by these findings where bivalves will use their shell as a reservoir for micronutrients and other substances. The NRRT assay revealed that lysosomal membrane destabilization had occurred and that the animals appeared to be stressed for the duration of the sampling period. Site 3, within the MPA, had the longest retention time. The retention times that were recorded were short when compared to other studies. This assay did however show potential as a basic monitoring tool from which more thorough investigations can be initiated. In conclusion, the study sites along the south coast of South Africa does not seem to be contaminated by Al, Zn, Cu or Fe when data is compared to international and local water quality guidelines, sediment quality guidelines and other studies. Also, as concentrations between sites did not differ greatly, it is inconclusive whether or not the MPA can be used as a reliable references site for in situ studies. More vigorous and lengthy studies should be undertaken to contribute to current knowledge of our indigenous species, Striostrea margaritacea and to aid in the development of better management of this resource as well as an ongoing monitoring programme.

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VonHandorf, Andrew P. "Cr(VI) Disrupts Chromatin Architecture." University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1595243461574043.

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Lou, Laiqing. "Arsenic uptake, accumulation and tolerance in Chinese brake fern (Pteris vittata L., an arsenic hyperaccumulator) under the influence of phosphate." HKBU Institutional Repository, 2008. http://repository.hkbu.edu.hk/etd_ra/928.

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Rhora, Jennifer. "Effect of Chromium VI on the Production and Behavior of Lytechinus variegatus (Echinodermata: Echiniodea)." Scholar Commons, 2005. https://scholarcommons.usf.edu/etd/833.

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Small amounts of chromium (VI) are carcinogenic in mammals. Concentrations of Cr in marine algae and seagrasses range from 0.06-7.17 /g DW and 0.1-30.6 g/g DW respectively. To test for an effect of these concentrations, production (change in organic material), righting response, feeding rates, absorption efficiency and fecal production were measured in Lytechinus variegatus from Sarasota fed prepared diets containing 0, 4.1, and 32g Cr/ g DW and individuals from Ft. DeSoto fed diets containing 0, 41 and 82g Cr/ g DW. The urchins were fed for 4-5 weeks, with weekly measurements of their feeding rates, absorption efficiency and fecal production. At the end of the experiment the urchins were righted to note any changes in behavior. Their gonads, gut, lantern and test with spines were weighed and ashed to calculate gonadal and gut indices and inorganic and organic percentage and content. After five weeks individuals in all treatments from experiment one showed no significant results. Urchins in all treatments from experiment two showed a significant decrease Individuals in all treatments had a significant increase in wet (P<0.001) and dry (P=0.005) weights as well as total organic material (P<0.001) in the gut of the urchins recieveing 82µg Cr/ g DW. There was significant decrease in the feeding rate (P<0.001) and absorption efficiency (P<0.001), countered by a significant increase in fecal production. The righting times were significantly different between the 0µg Cr/ g dry weight, 82µg Cr/ g DW and initial (P=0.031), but not the 41µg Cr/ g DW. Chromium in the feed at the concentrations used in this experiment does not affect the production or absorption efficiency of Lytechinus variegatus, but it does affect feeding rates, fecal production and righting response.

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Stahler, Adam Christopher. "Micro-Raman Imaging and Hyperspectral Analysis of Tibiotarsi from Chick Embryos Exposed to Sublethal Doses of Platinum Group Metals." Wright State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=wright1347480100.

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Shumba, Trust. "Removal of heavy metals from CRUD and slime dam material using soil washing and bioremediation." Thesis, Link to the online version, 2008. http://hdl.handle.net/10019/1536.

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Felix, Fabiana da Silva. "Avaliação ambiental de exposição a fumos metálicos em fundições." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/46/46133/tde-18092015-163514/.

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A Universidade de São Paulo (Instituto de Química e Faculdade de Ciências Farmacêuticas) e FUNDACENTRO têm desenvolvido um projeto nos pólos de fabricação de peças de torneiras e registros de Loanda/PR, visando a avaliação do ambiente de trabalho. Considerando as etapas do processo de fundição de latão para a confecção dos produtos, há a presença de fumos metálicos, provenientes da fundição e vazamento, que podem acarretar na intoxicação dos trabalhadores e, conseqüentemente, faz-se necessária a avaliação do risco ocupacional. Esta avaliação consiste da caracterização das partículas através da determinação de seus constituintes em massa por volume de ardo ambiente de trabalho. A concentração para particulados é expressa em µg m-3. Para isso, foi aplicada metodologia específica e reconhecida do National Institute of Organization Safety (NIOSH), a qual recomenda a utilização de espectrometria de emissão óptica com plasma acoplado indutivamente (ICP OES) para a determinação de As, Cd, Mn, Ni e Pb em amostras de ar. Foi proposta uma alternativa utilizando a voltametria de acumulação com redissolução anódica com eletrodo de gota pendente de mercúrio para a determinação de Cd e Pb, além da voltametria adsortiva com redissolução catódica com o mesmo eletrodo para Ni e voltametria de redissolução catódica com eletrodo de diamante dopado com boro para Mn, sendo que utilizou-se onda quadrada para a obtenção de todos os voltamogramas. De acordo com os resultados obtidos, foram propostas alterações tecnológicas no processo e adequação dos equipamentos de proteção no intuito de proteger a saúde e o bem estar dos trabalhadores, bem como evitar danos ao meio ambiente.
The Universidade de São Paulo, Instituto de Química e Faculdade de Ciências Farmacêuticas (University of São Paulo, Institute of Chemistry and Pharmaceutical Sciences College) and FUNDACENTRO have developed a project at the manufacturing facilities of stopcocks and faucet parts in Loanda/PR, aiming the evaluation of workplaces. Considering the stages of the brass foundry process in manufacturing those products, there are metallic fumes, originating from metal melting and pouring, which can result in human intoxication and, therefore, it is necessary to make an assessment of the occupational exposure. This assessment consists of collecting the particulate, measuring the mass of the contaminant, and then calculating the concentration by dividing the mass by the volume of sampled air. For particulates, concentration is expressed as µg m-3. For this assessment, it was applied a specific and recognized method of the National Institute of Organization Safety Health (NIOSH) which recommends the use of the technique of inductively coupled plasma optical emission spectrometry (ICP OES) to determine As, Cd, Mn, Ni and Pb in air samples. It was proposed an alternative method using the anodic stripping voltammetry with hanging mercury drop electrode (HMDE) to determine Cd and Pb, in addition to cathodic adsorptive stripping voltammetry with HMDE to determine Ni and cathodic stripping voltammetry with boron-doped diamond electrode to determine Mn. For these procedures were used square wave voltammetry to record all the voltammograms. According to the results of this work, we proposed technological changes in the production process and the adequacy of protection equipment in order to protect the health and well-being of workers, as well as to avoid damages to the environment.

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Sanchez, Chardi Alejandro. "La musaranya comuna, Crocidura russula (Hermann, 1780), com a bioindicador en estudis ecotoxicologics." Doctoral thesis, Universitat de Barcelona, 2013. http://hdl.handle.net/10803/129847.

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En aquesta memòria de tesi es detalla la quantificació de biomarcadors d’exposició (acumulació de Pb, Hg, Cd, Tl, Fe, Mg, Zn, Cu, Mn, Mo, Co, Ni, Cr, Sr, Ba i B a teixits tous i durs) i d’efecte (morfometria, hematologia, activitat enzimàtica, genotoxicitat i histopatologia) en un total de 243 exemplars de musaranya comuna, Crocidura russula (Hermann, 1780). En el present estudi, es va tenir en compte la importància de l’edat i el sexe en els paràmetres quantificats ja que són dos factors biòtics que expliquen part de la variabilitat observada. Les zones d’estudi van ser 4 zones contaminades i 4 zones de referència triades per la seva importància tant mediambiental (6 de les 8 zones estudiades tenen estatus de protecció parcial o total) com d’interès per la societat: l’abocador de Garraf, el més gran de la península Ibèrica, la mina abandonada d’Aljustrel a la zona portuguesa de la faixa piritosa ibèrica, el Parc Nacional de Doñana afectat pel vessament de la mina de pirita d’Aznalcóllar, situada a la part espanyola de la faixa piritosa ibèrica i el Delta de l’Ebre afectat diverses activitats humanes incloent caça, industria i residus domèstics. Dels exemplars analitzats, 138 van ser capturats pròpiament per estudis ecotoxicològics a 3 de les zones contaminades (Garraf, Aljustrel i Doñana) i 105 eren mostres de col•lecció procedents d’altres estudis ecològics (Delta de l’Ebre). Especialment en les zones contaminades estudiades, es van observar marcades diferències en la bioacumulació entre elements essencials i no essencials per diferències en biodisponibilitat, toxicitat, i capacitat de transferència i biomagnificació al llarg de les cadenes tròfiques entre ambdós grups d'elements. Els majors augments detectats als teixits de les musaranyes de les zones contaminades es van donar entre els metalls pesants no essencials (Pb, Cd, Hg, Tl i Ni), els nivells tissulars dels quals no estan metabòlicament regulats a mamífers, donant com a resultat alts increments a teixits durs i tous quan augmenta la biodisponibilitat al medi ambient. Dels elements quantificats només Pb, Hg, Cd, i, possiblement Tl, Ni, B, Ba i Sr, van acumular-se fins a nivells que poden ser tòxics en mamífers. Ja que hi ha escassa informació sobre com afecta l’exposició crònica a les poblacions naturals d’insectívors, les dades conjuntes dels biomarcadors d’efecte obtingudes serveixen com valors de referència per a l’espècie i poden contribuir a estimar els efectes tòxics sobre els organismes. Es van detectar disminucions en la massa corporal i l'activitat de GST, i increments de massa i patologies atribuïbles a la contaminació a fetge i ronyó i freqüència de micronuclis en les musaranyes de les zones contaminades. Dels dos factors biòtics estudiats, l'edat va ser el més important ja que 10 dels elements, amb especial rellevància en el cas del Cd, van presentar patrons d’acumulació diferencials entre joves i adults. Per contra, mascles i femelles de musaranya comuna només van presentar petites diferències en l'acumulació de Pb, Hg, Ni, Mo, Mn, Co i Fe. Com amb els marcadors d’exposició, la rellevància de edat en els biomarcadors d’efecte va ser també major que la del sexe per explicar la variabilitat observada. L’ús de diversos biomarcadors d’exposició d’efecte permeten d’una banda obtenir una millor idea del conjunt d'efectes tòxics de la contaminació sobre el normal desenvolupament dels sistemes biològics, així com indiquen la idoneïtat de la musaranya comuna com a bioindicador de contaminació ambiental especialment per l’avaluació de risc ambiental a zones protegides i per les poblacions humanes.
In this report, a quantification of biomarkers of exposition (accumulation of Pb, Hg, Cd, Tl, Fe, Mg, Zn, Cu, Mn, Mo, Co, Ni, Cr, Sr, Ba and B in soft and hard tissues) and effect (morfometry, haematology, enzymatic activity, genotoxicity and histopathology) in a total of 243 specimens of the greater white-toothed shrew, Crocidura russula (Hermann, 1780) was found. In the present study, the age- and sex-dependent variations were also considered in order to explain the variability due to these important biotic factors. The study sites were 4 polluted sites and 4 reference sites selected both for their environmental relevance (6 out the 8 sites have granted partial or total protection status) and for the interest for the society: the landfill of Garraf, the bigger dump site in the Iberian Peninsula; the abandoned mine of Aljustrel in the Portuguese part of the Iberian Pyrite Belt (IPB); the National Park of Doñana affected by the wastes of the mine of Aznalcóllar, sited in the Spanish part of the IPB; and the Ebro Delta disturbed during decades by several human activities including hunting, industries and domestic wastes. A total of 138 shrews were captured for ecotoxicological studies in 3 polluted sites (Garraf, Aljustrel, and Doñana) and 105 specimens were captured for other ecological studies and stored in a zoological collection (Ebro Delta). Especially in the polluted sites studied, there were marked differences between the bioaccumulation patterns of essential and non-essential elements due to differences in the bioavailability, toxicity, and transfer and bioaccumulation throughout the food chains between the two groups of elements. The highest increases in the tissues of shrews from the polluted sites were on non-essential heavy metals (Pb, Cd, Hg, Tl, and Ni), without metabolic regulation of tissular levels in mammals that ends in high burdens in soft and hard tissues when bioavailability increase in the environment. Among elements quantified, only Pb, Hg, Cd, and, probably Tl, Ni, B, Ba and Sr, were accumulated till levels that may produce toxic effects in mammals. The scarce information of the effects of chronic exposure in natural populations of insectivores render more relevant the use of a battery of biomarkers of effect, that serve as reference values for the species and as assessment of toxic effects in organism. Decreases of body mass and GST activity and increases of mass and pathologies attributable to pollution in liver and kidneys were detected in shrews from the polluted sites. Among biotic factors, age was important because 10 of the elements quantified, with special remark on Cd, showed differential bioaccumulation patterns in juveniles and adults. In contrast, only slight differences in bioaccumulation of Pb, Hg, Ni, Mo, Mn, Co, and Fe were found between males and females. The same pattern of importance of age and sex as in the biomarker of exposure was found in the biomarkers of effect. The use of several biomarkers of exposure and effect provide information of the whole toxic effects of pollution in the normal function of biological systems and point out C. russula as a suitable bioindicator of environmental pollution, specially to evaluate environmental risk both in protected sites and human populations.

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Ramalingam, Malarvili. "Metal exposure in non-occupationally exposed pregnant women of Western Australia and contribution of environmental sources." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2011. https://ro.ecu.edu.au/theses/450.

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Metals pollution is a growing global concern and human exposure has been associated with increased chronic and acute health effects even at low metal concentrations (Hu et al., 2006; US EPA, 2007; Rice et al., 2010; UNEP, 2010). Sensitive members of the population, such as neonates, children and pregnant women, in particular, are at increased risk due to their biological vulnerability (Jarup, 2003; Ettinger et al., 2007; US EPA, 2007). While much literature has examined exposure to metal contaminants, focussing on exposures from point sources, few studies have explored exposure in pregnant women and the factors that may influence their exposure. This study examined the degree of cadmium, copper, lead, manganese, mercury, nickel and uranium exposure in non-occupationally exposed pregnant women and the factors and sources contributing to their exposure. Studies have shown that environmental media are potential sources of metals exposure for humans, and exposure in the general population can occur through inhalation of contaminated air, ingestion of contaminated drinking water and food, or by dermal contact. This study is one of the few conducted in Australia, where source identification was carried out on the basis of biological monitoring (personal exposure) and residential environmental concentrations. Source identification of metals using chemometrics was conducted to identify whether drinking water, soil and dust were potential sources of maternal exposure. A cross-sectional study design was used to assess the exposure of pregnant women aged between 19 and 44 years to specific metals. One hundred and nineteen women were recruited via local hospitals and the community in different locations across Western Australia (WA). Exposure assessment was undertaken using biological and environmental sampling in combination with questionnaire information. Cadmium, copper, lead, manganese, mercury, nickel and uranium concentrations were determined in blood, urine, drinking water, soil and dust samples provided by the participants. Inductively coupled plasma mass spectrometry (ICP-MS) was used to determine a broad range of metals in blood, urine and drinking water, and inductively coupled plasma atomic emission spectrometry (ICP-OES) for metals in soil and dust. The samples targeted for this study, were anticipated to contain low metal concentrations as the study involves a non-occupationally exposed population. Hence, sensitive analytical methods with improved detection limits were essential. Emphasis was given to blood analysis because it involves direct assessment of human exposure to metals and also because it has high matrix variability (IPCS, 2000; UNEP, 2008). Therefore, this study included the optimisation of the microwave digestion method for measuring a broad range of elements simultaneously in human blood using ICP-MS. In this study, most women recorded low concentrations of metals in blood and urine. Metals were detected in most samples with the exception of mercury in urine and nickel in blood. On the whole, the geometric mean blood and urinary cadmium, copper, lead, manganese and mercury concentrations of these pregnant Australian women were similar to or lower than ranges reported in the international literature. However, a few individuals, had high exposure concentrations especially cadmium and mercury, which have been shown to be associated with adverse health effects in other studies. The geometric mean blood and urinary nickel concentrations were elevated. Uranium concentrations in both blood and urine samples were high. The metal concentrations in drinking water, soil and dust samples were generally low, with the exception of uranium in dust. Regression analysis indicated that drinking water, soil and dust were not important contributors to maternal exposure at background concentrations, however, a chemometrics study revealed that mixed sources of environmental media may have significant contribution to metals exposure. Drinking water, soil and dust were identified as potential sources of metals in blood, but not in urine. Demographics, behaviours and lifestyle characteristics were found to be less contributing to maternal exposure but there were indications that diet and water supply might be important contributors. The results obtained provide some information on personal exposure concentrations of pregnant women residing in Western Australia resulting from non-occupational exposure to cadmium, copper, lead, manganese, mercury, nickel and uranium, which can be used as a benchmark for future studies. Furthermore, this study employed a chemometrics approach and specifically partial least squares (PLS) to identify the sources. This allowed the determination of sources contributing to human exposure at lower metal concentrations. Finally, the presence of high concentrations of cadmium, lead, manganese and mercury in some maternal blood and urine samples, and the generally elevated nickel and uranium concentrations are cause for concern. Further studies are required to better understanding the risks associated with metals exposure and so provide a safer environment for all.

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Hitron, John Andrew. "AN OPTIMIZED SOLID-PHASE REDUCTION AND CAPTURE STRATEGY FOR THE STUDY OF REVERSIBLY-OXIDIZED CYSTEINES AND ITS APPLICATION TO METAL TOXICITY." UKnowledge, 2018. https://uknowledge.uky.edu/toxicology_etds/22.

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The reversible oxidation of cysteine by reactive oxygen species (ROS) is both a mechanism for cellular protein signaling as well as a cause of cellular injury and death through the generation of oxidative stress. The study of cysteine oxidation is complicated by the methodology currently available to isolate and enrich oxidized-cysteine containing proteins. We sought to simplify this process by reducing the time needed to process samples and reducing sample loss and contamination risk. We accomplished this by eliminating precipitation steps needed for the protocol by (a) introducing an in-solution NEM-quenching step prior to reduction and (b) replacing soluble dithiothreitol reductant with a series of newly-developed high-capacity polyacrylamide-based solid-phase reductants that could be easily separated from the lysate through centrifugation. These modifications, collectively called resin-assisted reduction and capture (RARC), reduced the time needed to perform the RAC method from 2-3 days to 4-5 hours, while the overall quality and quantity of previously-oxidized cysteines captured was increased. In order to demonstrate the RARC method’s utility in studying complex cellular oxidants, the optimized methodology was used to study cysteine oxidation caused by the redox-active metals arsenic, cadmium, and chromium. As(III), Cr(VI), and Cd(II) were all found to increase cysteine oxidation significantly, with As(III) and Cd(II) inducing more oxidation than Cr(VI) following a 24-hour exposure to cytotoxic concentrations. Label-free proteomic analysis and western blotting of RARC-isolated oxidized proteins found a high degree of commonality between the proteins oxidized by these metals, with cytoskeletal, translational, stress response, and metabolic proteins all being oxidized. Several previously-unreported redox-active cysteines were also identified. These results indicate that cysteine oxidation by As(III), Cr(VI), and Cd(II) may play a significant role in these metals’ cytotoxicity and demonstrates the utility of the RARC method as a strategy for studying reversible cysteine oxidation by oxidants in oxidative signaling and disease. The RARC method is a simplification and improvement upon the current state of the art which decreases the barrier of entry to studying cysteine oxidation, allowing more researchers to study this modification. We predict that the RARC methodology will be critical in expanding our understanding of reactive cysteines in cellular function and disease.

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Leung, Ho Man Homan. "Interactions of arbuscular mycorrhizal fungi with an arsenic hyperaccumulator plant (pteris vittata) on the uptake of arsenic." HKBU Institutional Repository, 2008. http://repository.hkbu.edu.hk/etd_ra/945.

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Capri, Maria da Rosa. "Avaliação de elementos potencialmente tóxicos em tintas." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/46/46133/tde-05072016-112942/.

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Neste trabalho são apresentados os resultados da determinação, por ICP OES, de elementos tóxicos e/ou potencialmente tóxicos (AI, Cr, Ni, Cu, Cd, As, Co e Pb) em tintas de acabamento imobiliário à base de água ou de solvente orgânico. Foram desenvolvidas e comparadas método de digestão de amostras utilizando diferentes misturas ácidas em bombas de decomposição, em fomo de microondas (sistema com radiação focalizada e com cavidade) e método de cinzas. O Método de digestão utilizando fomo de microondas com cavidade permitiu solubilização rápida e eficiente de todos os tipos de tintas testados, em tempo inferior a 35 minutos. As método apresentaram valores aceitáveis para a maioria dos elementos nos testes de adição e recuperação dos analitos. Os resíduos resultantes da digestão foram avaliados por MEV-EDS e não apresentaram os elementos estudados, comprovando a eficiência da metodologia. Mercúrio foi determinado usando um Analisador Direto de Mercúrio (DMA) e apresentou valores entre 43,0 ± 4,5 e 188 ± 9 µg Kg-1, valor considerado baixo quando comparado ao limite de 100 mg Kg-1, estabelecido na norma NRR 10004 para disposição de resíduos sólidos sem instalações especiais. O estudo da migração dos elementos para o ambiente após a exposição da tinta a agentes \"agressores\" , como raios ultravioletas e umidade, foi realizado usando câmara do tipo \"Weather-Ometer\" (envelhecimento acelerado). A avaliação dos resultados foi feita por MEV EDS e ICP OES. As micrografias de MEV mostraram que houve mudança na morfologia do polímero que foi submetido ao intemperismo acelerado. Os resultados obtidos não foram conclusivos quanto à migração dos analitos em função da baixa razão entre as massas degradada e não degradada das amostras. Uma proposta de metodologia para a avaliação por ICP OES das tintas e da disponibilidade de elementos tóxicos e potencialmente tóxicos, baseada na lixiviação de amostras secas em ambiente controlado é apresentada. São mostrados resultados de lixiviação de AI, Cr, Ni, Cu, Cd, As, Co e Pb com vários extratores e tempos diferentes de extração. Os resultados mostram que ocorre a migração de alguns elementos para as soluções estudadas e que, dos extratores avaliados, a chuva ácida apresentou maior potencial de lixiviação.
This work presents the results of the determination, using ICP OES, of the toxic and/or potentially toxic elements (AI, Cr, Ni, Cu, Cd, As, Co and Pb) in paints based in water or organic solvent. Sample digestion method were developed and compared using different acid mixtures in decomposition pumps, in microwave oven (focused and with cavity) and ash method. The digestion method using microwave oven with cavity allowed fast and efficient solubilization of ali tested types of paints, in inferior time to 35 mino The methodologies showed acceptable values for the majority of the elements using addition and recovery tests. The residues resulting of the digestion were analyzed by SEM-EDS and did not present the studied elements, checking the efficiency of the method. Mercury was determined using a Direct Mercury Analyzer (DMA) presenting values between 43.0 ± 4.5 and 188 ± 9 µg.kg-1, value considered low when compared to the Iimit of 100 mg.kg-1, established in the norm NBR 10004 for disposition of solid residues without special installations. The migration of the elements for the environment was studied afier the exposition of the paints to aggressor agents, Iike ultraviolet radiation and humidity, using a Weather-Ometer type chamber (accelerated aging). The evaluation of the results was performed by SEM-EDS and ICP-OES. The SEM micrographs showed changes on the polymer morphologies submitted to accelerated aging. The obtained results were not conclusive on the migration of elements because of the low mass ratio between the degraded and non-degraded samples. The proposed method for the evaluation by ICP-OES of paints and the disponibility of toxic and potentially toxic elements, based on the lixiviation of dry samples in controlled environment is described. Lixiviation results of AI, Cr, Ni, Cu, Cd, As, Co and Pb using several different removal agents and extraction times are presented. The results show that happens the migration of some elements for the studied solutions and that, among ali removal agents, the acid rain showed the highest lixiviation potential. that, among ali removal agents, the acid rain showed the highest lixiviation potential.

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Johnson, Adam Nicholas. "Toxicological Comparison of Heavy Metal Salt and Semiconductor Nanoparticle Exposure in Zebrafish (Danio rerio)." Fogler Library, University of Maine, 2007. http://www.library.umaine.edu/theses/pdf/JohnsonAN2007.pdf.

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45

Li, Hui. "The role of arbuscular mycorrhizal fungi (AMF) on the tolerance and accumulation of arsenic in rice (Oryza sativa L.)." HKBU Institutional Repository, 2012. https://repository.hkbu.edu.hk/etd_ra/1409.

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46

Parviz, Maryam. "Evaluation of Zinc Toxicity Using Neuronal Networks on Microelectrode Arrays: Response Quantification and Entry Pathway Analysis." Thesis, University of North Texas, 2007. https://digital.library.unt.edu/ark:/67531/metadc3928/.

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Murine neuronal networks, derived from embryonic frontal cortex (FC) tissue grown on microelectrode arrays, were used to investigate zinc toxicity at concentrations ranging from 20 to 2000 mM total zinc acetate added to the culture medium. Continual multi-channel recording of spontaneous action potential generation allowed a quantitative analysis of the temporal evolution of network spike activity generation at specific zinc acetate concentrations. Cultures responded with immediate concentration-dependent excitation lasting from 5 to 50 min, consisting of increased spiking and enhanced, coordinated bursting. This was followed by irreversible activity decay. The time to 50% and 90% activity loss was concentration dependent, highly reproducible, and formed linear functions in log-log plots. Network activity loss generally preceded morphological changes. 20% cell swelling was correlated with 50% activity loss. Cultures pretreated with the GABAA receptor antagonists bicuculline (40 mM) and picrotoxin (1 mM) lacked the initial excitation phase. This suggests that zinc-induced excitation may be mediated by interfering with GABA inhibition. Partial network protection was achieved by stopping spontaneous activity with either tetrodotoxin (200 nM) or lidocaine (250 mM). However, recovery was not complete and slow deterioration of network activity continued over 6 hrs. Removal of zinc by early medium changes showed irreversible, catastrophic network failure to develop in a concentration-dependent time window between 50% and 90% activity loss. Investigation of entry routes suggested the L-type but not N-type calcium channels to be the main entry pathway for zinc. Data are presented implicating the chloride channel to be an additional entry route.

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47

Chan, Wai Fung. "The roles of arbuscular mycorrhizal fungi in arsenic uptake and tolerance of upland rice." HKBU Institutional Repository, 2011. http://repository.hkbu.edu.hk/etd_ra/1257.

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Hu, Junli. "Risk assessment and mycorrhizal remediation of cadmium contamination in vegetable farms around the Pearl River Delta, China." HKBU Institutional Repository, 2013. http://repository.hkbu.edu.hk/etd_ra/1484.

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Escorihuela, Martí Laura. "Computational characterisation of metal oxide nanoparticles for hazard screening and risk assessment." Doctoral thesis, Universitat Rovira i Virgili, 2019. http://hdl.handle.net/10803/669615.

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Donades les propietats intrínseques de les nanopartícules els d’òxids metàl·lics ( MeO) NPs són el pilar fonamental de aplicacions avançades tecnològicament en àrees com electrònica, farmàcia o medicina. En canvi, existeix un important buit pel que fa com influencien les seves propietats físico químiques i el risc que suposen per la salut humana. L’avaluació de la toxicitat dels nanomaterials es una dura tasca que involucra múltiples condicions experimentals. Els mètodes computacionals, in-silico, teòrics i estadístics, avaluen, determinen i prediuen processos o fins i tot propietats de les substàncies. Apart, de la urgència que existeix legislativa per avaluar el risc que comporten, existeix un buit en la literatura, donat que els diferents experiments que si expliquen tenen buits en la descripció de la metodologia emprada o detalls experimentals, llavors no es útil per la avaluació del risc. El mètode més popular computacional, és Desnity Functional theory (DFT) , basat en en la mecànica quàntica . En aquesta tesi es desenvolupa un estricte estudi dels millors mètodes que permeten optimitzar des de la energia de l’estat fonamental per superfícies, nanotubs i nanopartícules esfèriques. Per obtenir valors més precisos per la determinació del band gap, s’ha incrementat el nivell de teoria utilitzant el DFT+U, finalment per obtenir valors per sistemes de 3000 àtoms per la simulació de sistemes biològics , s’ha implementat el mètode DFTB de dinámica molecular, també utilitzat per la avaluació de la solubilitat. Els resultats computacionals obtinguts per ZnO han estat prometedors, llavors s’ha provat per al TiO2, demostrant que la metodologia ideada funciona. Finalment, les dades obtingudes s’han utilitzat per crear model de predicció de propietats band gap i solubilitat per NPs més grans i amb aquestes poder generar model nano-QSAR( Quantitat-eStructura-Acivitat-Relació), on es relacionen les propietats estudiades amb el nivell de toxicitat del MeO NP.
Las propiedades intrínsecas de las nanopartículas de óxidos metálicos (MEO) NPs son el pilar fundamental de aplicaciones avanzadas tecnológicamente en áreas como electrónica, farmacia o medicina. En cambio, existe un importante vacío en cuanto cómo influyen sus propiedades físico-químicas y el riesgo que suponen para la salud humana, la evaluación de la toxicidad de los nanomateriales es un dura tarea que involucra múltiples condiciones experimentales. Los métodos computacionales, in-silico, teóricos y estadísticos, evalúan, determinan y predicen procesos o incluso propiedades de las sustancias. Además de la urgencia que existe legislativa para evaluar el riesgo que conllevan, existe un vacío en la literatura, dado que en los diferentes experimentos que se explican en la literatura tienen vacíos en la explicación de la metodología empleada o detalles experimentales, entonces no son útiles para la evaluación del riesgo. El método más popular computacional, es Density Functional theory (DFT), basado en la mecánica cuántica. En esta tesis se desarrolla un estricto estudio de los mejores métodos que permiten optimizar desde la energía del estado fundamental para superficies, nanotubos y nanopartículas esféricas. Para obtener valores más precisos para la determinación del band gap, se ha incrementado el nivel de teoría utilizando el DFT + U, finalmente para obtener valores para sistemas de 3000 átomos para la simulación de sistemas biológicos, se ha implementado el método DFTB de dinámica molecular, también utilizado para la evaluación de la solubilidad. Los resultados computacionales obtenidos por ZnO han sido prometedores, entonces se ha probado para el TiO2, demostrando la validez de la metodología ideada. Finalmente, los datos obtenidos se han utilizado para crear modelos de predicción de propiedades (band gap y solubilidad) para NPs más grandes y con estas poder generar modelo nano-QSAR ( Cantidad-eStructura-Acividad-Relación), donde se relacionan estas propiedades estudiadas con el nivel de toxicidad del MeO NP.
Given the intrinsic properties, metal oxide nanoparticles (MeO) NPs are the cornerstone of a wide range of technologically advanced applications in areas such as electronics, pharmacy or medicine. However, there is still an important knowledge gap regarding how size influences their physicochemical properties and the risk to human health. Toxicity assessment of NMs is a daunting task involving multiple testing conditions. Computed based methods, in silico methods, based on theoretical and statistical domain, evaluate, determine and predict processes or even substance properties. Furthermore, the legislation urgency for risk assessment exits given that the data for the environmental risk assessment found in literature is uncertain and present knowledge gaps, though is not useful for the risk assessment for nanoparticles. The most popular in silico method based on quantum mechanics for chemistry is Density Functional Theory (DFT). In this thesis we performed a strict and deep study of best methods to evaluate the band gap and the solubility of MeO NP. The use of periodical-DFT methods has allowed us to optimise the ground state energy for surfaces, nanotubes and spherical nanoparticles. To get more reliability for band gap determination, the exchange-correlation functional has been improved to DFT+U. After that, to reach to large systems up to 3000 atoms in order to simulate more realistic biological systems, we used DFTB methodology for band gap prediction; we also coupled DFTB with Molecular Dynamics to compute NP solubility. The computational results obtained with the methodology developed in this thesis for the ZnO case have been promising and, in order to make more robust the method employed, it has been tested for TiO2 too, showing an excellent efficiency in the results. Finally, the data obtained from the prediction models of band gap and solubility models have been used to create nano-QSAR (Quantity-Structure-Activity-Relationship) models.

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Watanabe, Cláudia Hitomi. "Avaliação ecotoxicológica de metais/metalóides e interferentes endócrinos em frações de substâncias húmicas de diferentes tamanhos moleculares /." Sorocaba, 2015. http://hdl.handle.net/11449/124025.

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Orientador: André Henrique Rosa
Coorientador: Renata Fracácio
Banca: Alessandra Emanuele Tonietto
Banca: Viviane Moschini Carlos
Resumo: No presente trabalho, ensaios de toxicidade com o metalóide arsênio, o metal cobalto e o contaminante emergente17β-estradiol foram estudados na presença e ausência das substâncias húmicas aquáticas (SHA) e suas frações de diferentes tamanhos moleculares (<5, 5-10; 10-30; 30-100 e >100 kDa), utilizando-se os organismos Ceriodaphnia dubia e Pseudokirchneriella subcapitata. Aos ensaios utilizando-se o organismo C. dubia, a influência das SHA em contato com o metal arsênio na redução da toxicidade por análise estatística aumentou a reprodução. Nas diferentes frações de SHA observou-se variação de toxicidade nas frações de tamanhos moleculares maiores, na seguinte ordem crescente de toxicidade: F1=F2Abstract: At this work, toxicity tests using metalloid arsenic, metal cobalt and emerging contaminant 17β-estradiol were studied in the presence and absence of aquatic humic substances (AHS) and its fractions of different molecular sizes (<5, 5-10; 10-30; 30-100 and > 100 kDa), using the Ceriodaphnia dubia and Pseudokirchneriella subcapitata organisms. The tests using C. dubia, influence of AHS contact arsenic metal in toxicity reducing by statistical analysis AHS and the different fractions showed different behavior in each other, reducing toxicity fractions of larger molecular size, in decreasing order of toxicity: F1 = F2 Mestre

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Dissertations / Theses on the topic 'Metals – Toxicology'

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