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Biomarcadores enzimáticos e ecotoxicidade por cobre em Eisenia andrei (Bouché 1972) / Biomarkers enzyme and ecotoxicity of copper in Eisenia andrei (Bouché 1972)Ferreira, Talita 16 October 2015 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / The indiscriminate use of agricultural supplies can cause soil pollution, affecting the flora, fauna and ecological relationships. Among these chemical compounds used in agriculture, there is the Bordeaux mixture. The intense use of this fungicide results in a considerable copper addition in the soil, may cause damage to exposed organisms. This study aimed to evaluate the toxicological effects of different copper doses, (0, 35, 70, 105, 140 e 175 mg.Kg-1) applied in soil, at earthworms Eisenia andrei biomass and reproduction, through ecotoxicological tests as well as the effects of exposure to antioxidant enzyme activity, by the enzymes catalase and glutathione S-transferase (GST and CAT), on neurotransmission biomarkers such as acetylcholinesterase (AChE) and cell membrane lipid peroxidation through the levels of malondialdehyde (MDA). The ecotoxicological results showed that the largest copper doses tested, (140 e 175 mg.Kg-1) were toxic, because the worms had a mean biomass reduction and cocoons. In the enzyme assessments, an increase in the glutathione-S-transferase activity was observed as the antioxidant defense mechanism. The significant MDA levels increase and the acetylcholinesterase activity inhibition, indicating the cell membrane lipid peroxidation occurrence and neurotransmission changes as a result of oxidative stress caused by the metal. / O uso indiscriminado de insumos agrícolas pode causar a poluição dos solos, comprometendo a flora, fauna e as relações ecológicas. Dentre os insumos químicos utilizados na agricultura, destaca-se a calda bordalesa. Sua intensa utilização resulta em uma adição considerável de cobre ao solo, podendo causar danos aos organismos expostos. O presente estudo teve como objetivo determinar os efeitos toxicológicos de diferentes doses de cobre: 0, 35, 70, 105, 140 e 175 mg.Kg-1 aplicado ao solo, na biomassa e reprodução das minhocas Eisenia andrei, através dos testes ecotoxicológicos assim como os efeitos da exposição a nível enzimático antioxidante, através das enzimas catalase e glutationa S-transferase (CAT e GST), sobre biomarcadores de neurotransmissão como a acetil-colinesterase (AChE) e na peroxidação lipídica da membrana celular através dos níveis de malondialdeído (MDA). Os resultados ecotoxicológicos, evidenciaram que as maiores doses de cobre testadas, (140 e 175 mg.Kg-1) foram tóxicas, pois as minhocas apresentaram redução média na biomassa e no número de casulos. Em relação aos níveis enzimáticos, foi observado um incremento na atividade das enzimas glutationa-S-transferase, como mecanismo de defesa antioxidante. O aumento significativo nos níveis de MDA observados e a inibição da atividade da acetil-colinesterase, indicam a ocorrência da peroxidação lipídica da membrana celular e alterações na neurotransmissão em decorrência do estresse oxidativo ocasionado pela presença do metal.
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TOLERÂNCIA DE ARBÓREAS NATIVAS SUBMETIDAS A SUBSTRATOS AMENIZANTES DE SOLO CONTAMINADO COM COBRE / WOODY NATIVE SPECIES TOLERANCE TO CONTAMINATED SOIL WITH COPPER WITH AMENDMENTSGrolli, Andre Luís 29 February 2016 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / More contaminated areas with copper were discovered and this had contributed negatively for plants establishment, so more studies are need to reutilize this areas. Thus, the objective of this work is to enable the attenuation of the contamination on native woody seedlings production in contaminated soil with copper. Three experiments were realized. The first involving the evaluation of the growth and quality of Bauhinia forficata Link, Pterogyne nitens Tul and Enterolobium contortisiliquum Vell. seedlings in soil with dosis of copper. On the second work, the effect of broiler litter was evaluated on soil chemical attributes and the growth of E. contortisiliquum seedling. On the third, the effect of broiler litter (CA) and mix of broiler litter with commercial substrate (CA+SC) evaluated to attenuation of copper contamination in soil and E. contortisiliquum potential to descontamination the soil. E. contortisiliquum had more tolerance to high copper dosis than B. forficate and P. nitens. The addition of 36% of CA on the SC and 33% on the peat enables increasing on morphological parameters of E. contortisiliquum seedlings. The utilization of the CA+SC was efficient to attenuation of the copper contamination. The morphological parameters was stimulated by the addition of the mix, with better results in 20 and 30% in contaminated soil with 400 mg of kg-1 of soil. / Tem sido evidenciado um aumento em áreas contaminadas com cobre e este fato tem contribuído negativamente para o estabelecimento de plantas, sendo necessários estudos de alternativas para reutilização destas áreas. Diante disso, o objetivo desse trabalho foi possibilitar o uso de amenizantes de contaminação na produção de mudas de espécies nativas em solo contaminado com cobre. Para atender o objetivo foram realizados três experimentos. O primeiro envolveu a avaliação da interferência de doses crescentes de cobre aplicado ao solo no crescimento e na qualidade de mudas de Bauhinia forficata Link(pata de vaca), Pterogyne nitens Tul (carne de vaca) e Enterolobium contortisiliquum Vell. (timbaúva) No segundo experimento avaliou-se o efeito de proporções de cama de aves nos atributos químicos do solo e morfológicos de crescimento de mudas de timbaúva e o terceiro experimento avaliou-se o efeito da cama de aviário e a mistura de cama de aviário com substrato comercial como amenizante de cobre no solo e o potencial de Enterolobium contortisiliquum para descontaminação. As mudas de timbaúva toleram maiores doses de cobre no solo em relação à pata de vaca e carne de vaca. A adição de aproximadamente 36% de cama de aviário ao substrato comercial e de 33% à turfa possibilita aumento nos parâmetros morfológicos de mudas de timbaúva. A utilização cama de aviário + substrato comercial foi eficiente como amenizante da contaminação do solo com cobre. Os parâmetros morfológicos, foram estimulados com a adição de cama de aviário + substrato comercial, obtendo os melhores resultados com a dição de 20 a 30 % em solo contaminado com 400 mg de Cu Kg -1 de solo.
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Metal-logotyper och konsumenter : En studie om identitetsskapandeBengtsson, Carl, Lundin, Paula January 2017 (has links)
Syftet är att undersöka vilken påverkan heavy metal bands logotyper har och vilket budskap de förmedlar till kunden. Därefter vill vi undersöka vilken identitet dessa logotyper förmedlar till kunden. 1. Vad formar relationen mellan kund och logotyp för att skapa en identitet hos konsumenten inom heavy metal subgruppen? 2. Vilken påverkan har heavy metal bands logotyper på kunden? Metod Uppsatsen är formade efter kvalitativ studie. Ansatsen är anpassad efter induktion. Empiriska datan utgörs av fem semistrukturerade djupintervjuer och två semistrukturerade fokusgruppsintervjuer. Slutsatser Studiens resultat i den första forskningsfrågan identifierar fem lager av relationer till varumärket som är i ordningen: Utseende, lojalitet, samhörighet, provokation och den personliga identiteten. De tillsammans skapar det som definierar kundens identitetsskapande förhållande till logotypen. Andra forskningsfrågan har vi identifierat att logotypen är en del av identiteten då den symboliskt representerar bandet och musiken medan det underliggande budskapet hos logotypen representerar minnet, gemenskapen, intresset och identiteten.
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Heavy metal removal and water treatment using UpsaliteErenbo, Philip January 2017 (has links)
Ion exchange reactions between Upsalite, a mesoporous magnesium carbonate, and metal ions of cadmium, lead and nickel have been studied to evaluate the capacities of Upsalite as a water treatment agent. Uptake capacity and reaction kinetics have been evaluated using a batch experiment and atomic absorption spectroscopy. Post reaction materials from the reaction between Upsalite and each of the three metal ions have been investigated with XRD, SEM and TGA in order to determine what species have been formed during the ion exchange. The maximum uptake capacity of Upsalite was found to be 990 mg/g for cadmium ions and 470 mg/g for nickel ions. The evaluation of the uptake capacity of lead ions in Upsalite was not conclusive but the results indicate a maximum uptake capacity of at least 4400 mg/g. The uptake capacity for lead ions is to high be explained by ion exchange alone and is proposed to be from both ion exchange and adsorption. The reaction between Upsalite and cadmium ions resulted in the formation of crystalline CdCO3 (Otavite) with some parts of MgCO3 and crystalline MgO remaining from the original material. Post reaction materials from the reaction between nickel ions and Upsalite were found to be amorphous and contained both MgCO3 and crystalline MgO. The reaction between Upsalite and lead ions resulted in crystalline hydrocerussite (Pb3(CO3)2(OH)2).
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Phytoremediation of heavy metal and PAH contaminated soil : effects of bacterial inoculation on PAH removal, metal speciation, bioavailability and uptake by Sedum alfrediiLi, Wai Chin 01 January 2007 (has links)
No description available.
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Metal bioaccumulation and biomarker responses in tigerfish, Hydrocynus vittatus, from three South African populationsFisher, Eve Mariel 07 June 2012 (has links)
M.Sc. / Pollutants present in minute concentrations in aquatic environments and which possess long residence times may be accumulated by aquatic organism such as fish, resulting in adverse affects. Bioaccumulation and biomarker responses are often used to qualify and quantify pollutant exposure and effect, and for this reason form a major part of many environmental assessments. To interpret bioaccumulation and biomarker responses the physico-chemical parameters of the environment should be known. This study aimed to spatially and temporally assess the environmental partitioning of heavy metals in three South African freshwater systems, namely the Pongolapoort Dam, Olifants and Luvuvhu Rivers, and to relate these concentrations to bioaccumulation and biomarker responses in tigerfish, Hydrocynus vittatus. This is because there is relatively little known about the bioaccumulation potential and stress responses of tigerfish to pollutants and they have recently become listed as a protected species. Result from this study showed that there were few differences between seasons in terms of metal bioaccumulation in the Pongolapoort Dam with the exception of Se, Zn and Fe. Selenium and Fe concentrations were linked to concentrations found in the environment, whereas Zn was attributed to a disruption in homeostasis within the fish. Increases in MT were found during the winter months and were attributed to increased metal concentrations at this time, namely Zn and Se, whereas decreases in CEA and PC were observed at this time and were linked to depleted energy reserves, stress and a reduction in the presence of pesticides as a result of decreased runoff during the winter months. It was found in the Olifants and Luvuvhu Rivers that there were no distinct decreases in metal concentrations as the rivers flowed through the KNP, and processes such as rainfall, remobilization of sediments, distance of the study area from the source and geology played a great role in the distribution of metals. Metal concentrations in the Olifants River water, sediment and fish were, for the most part, found to be lower than previous studies, possibly due to improvement in management strategies or increased buffering of this river. Only Al and As were significantly higher in tigerfish from the Olifants River, and this was reflected in high MT concentrations. It was suggested that tigerfish from the Olifants River have developed effective mechanisms for the excretion and detoxification of heavy metals that they are exposed to as a result of extended exposure. Concentrations of AChE were also significantly inhibited in tigerfish from the Olifants River which is indicative of greater concentrations of organophosphates and carbamate pesticides than the other sites. Tigerfish from the Pongolapoort Dam had signifcantly higher levels of MT and significantly inhibited concentrations of AChE in comparison to tigerfish from the Luvuvhu River. The tigerfish from the Luvuvhu River had significantly higher concentrations of Se in muscle tissue. Tigerfish from the Luvuvhu River, also experienced stress as a result of pollution as was apparent from significantly depleted energy reserves in comparison to the other sites under study, and higher concentrations of PC and CYP1A which are typical biomarkers responding to halogenated and aromatic pesticides, such as deltamethrin and endosulfan. It was recommended that further studies be done to assess the presence of pesticides within these systems to determine the contribution of these pollutants to the state of tigerfish
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Crescimento, tolerância e potencial fitorremediador de leucaena leucocephala em solo contaminado por cobre e ferro /Bomfim, Nayane Cristina Pires. January 2020 (has links)
Orientador: Liliane Santos de Camargos / Resumo: As intensas atividades antropogênicas têm aumentado as concentrações de metais pesados no solo, por meio do uso excessivo de produtos químicos e do descarte inadequado e acúmulo de resíduos sólidos e líquidos, por exemplo, surgindo assim riscos de poluição do solo e corpos d’água. O desenvolvimento de tecnologias sustentáveis, efetivas e de baixo custo para recuperação de áreas contaminadas por metais pesados é de extrema necessidade. A fitorremediação é uma técnica, de baixo custo, que utiliza plantas na recuperação de solos contaminados por metais pesados. Espécies de leguminosas apresentam características favoráveis para crescerem rapidamente em solos degradados, o que é uma característica importante quando considera-se o potencial para fitorremediação destes contaminantes. Objetivou-se caracterizar a resposta fisiológica, determinar a tolerância e o potencial fitorremediador de Leucaena leucocephala aos metais cobre e ferro. O experimento foi conduzido em casa de vegetação, em delineamento inteiramente casualizado para ambos os metais. O solo foi tratado com cinco doses, além do controle (0, 100, 200, 300, 400 e 500 mg/dm3 solo), em sacos de mudas com capacidade para 2 dm3 de solo. Sementes de L. leucocephala foram semeadas diretamente no solo contaminado e cultivadas por 120 dias. Os parâmetros fotossintéticos, foram analisados; o material vegetal foi coletado e os tecidos foram separados, medidos e pesados para avaliação de crescimento. Teores de clorofila e carotenoide... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The intense anthropogenic activities have increased the concentrations of heavy metals in the soil, through the excessive use of chemicals and the improper disposal and accumulation of solid and liquid residues, for example, thus resulting in risks of pollution of the soil and water bodies. The development of sustainable, effective and low-cost technologies for the recovery of areas contaminated by heavy metals is extremely necessary. Phytoremediation is a technique that uses plants to recover soils contaminated by heavy metals. Legume species have favorable characteristics to grow quickly in degraded soils, which is an important characteristic when considering the potential for phytoremediation of these contaminants. The objective was to characterize the physiological response, to determine the tolerance and phytoremediation potential of Leucaena leucocephala to copper and iron metals. The experiment was carried out in a greenhouse, in a completely randomized design for both metals. The soil was treated with five doses, in addition to the control (100, 200, 300, 400 and 500 mg/dm3 soil), in seedling bags with a capacity of 2 dm3 soil. Leucaena leucocephala seeds were sown and cultivated for 120 days. The photosynthetic parameters were analyzed; the plant material was collected and the tissues were separated, measured and weighed for growth evaluation. Chlorophyll and carotenoid contents were quantified in the leaves. Nutrient contents in plants and soil were determined. The ... (Complete abstract click electronic access below) / Mestre
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Kinetika i mehanizam uklanjanja odabranih metala iz vode adsorpcijom na aminofunkcionalizovanom ugljeničnom nanomaterijalu / The kinetics and mechanism of removal of selected metals from water by adsorption on amino functionalized carbon nanomaterialsŠućurović Aleksandra 27 September 2017 (has links)
<p>Predmet istraživanja ove doktorske disertacije bio je ispitivanje adsorpcionog ponašanja As(III) i odabranih metala (Cu(II), Cd(II), Pb(II), Cr(VI)) na amino- funkcionalizovanim višeslojnim ugljeničnim nanocevima, MWCNT-NH<sub>2 </sub>, na četiri odabrane pH vrednosti (3; 4,5; 6 i 11) i pri različitim sastavima vodenog rastvora (prisustvo hlorida, nitrata, sulfata i fosfata), a u cilju ispitivanja mogućnosti primene MWCNT-NH<sub>2</sub> za uklanjanje arsena i jona metala iz vodenih rastvora u oblasti relativno niskih koncentracija (0,01-3 mg L <sup>-1</sup> ). Fokus ove doktorske disertacije<br />je bio na utvrđivanju mehanizma procesa adsorpcije u ispitivanim uslovima. Adsorpciju arsena i metala na MWCNT-NH<sub>2</sub> najbolje je opisao reakcioni model pseudo-drugog reda što znači da adsorpcija može biti pripisana uspostavljanju hemijskih interakcija između adsorbata i vezivnih grupa na površini adsorbenta. Modelovanje brzine Weber Morris-ovim difuzionim modelom ukazalo je na to da unutarčestična difuzija, iako sporiji korak od eksterne difuzije, nije jedini ograničavajući korak u procesu adsorpcije, već su za to odgovorne i interakcije ispitivanih jona sa vezivnim mestima na površini adsorbenta. U ravnotežnim uslovima, na različitim pH vrednostima, adsorpcija se mogla opisati Langmuir-ovim i Freundlich-ovim adsorpcionim modelima. Kapacitet i afinitet adsorbenta, kao i sam mehanizam adsorpcije, značajno su bili uslovljeni pH vrednošću rastvora, kako zbog karakteristika površine ispitivanog adsorbenta uslovljenih pH vrednošću, tako i zbog uticaja pH vrednosti rastvora na pojavne hemijske oblike u kojima se arsen i metali nalaze. Ispitivanje uticaja anjona pokazalo je da je prisustvo hlorida povećalo afinitet površine MWCNT-NH<sub>2 </sub>ka jonima arsena i svih metala u oblasti niskih<br />koncentracija, dok je prisustvo hlorida, nitrata, sulfata i fosfata pozitivno uticalo na afinitet površine (od 2 do 8 puta veći u odnosu na dejonizovanu vodu) MWCNT-NH<sub>2</sub><br />ka Cu(II) u oblasti viših koncentracija. Najmanji uticaj anjona na afinitet površine ka vezivanju metala primećen je kod hroma. Pretpostavljeni mehanizmi uklanjanja arsena i odabranih metala u prisustvu anjona ukljuĉuju reakcije građenja različitih vrsta spoljašnje- i unutrašnje-sfernih kompleksa, jonske izmene, kao i elektrostatičke interakcije koje se ostvaruju između pozitivno naelektrisane površine MWCNT-NH<sub><span style="font-size: 8.33333px;">2</span></sub> i anjona, na pH vrednostima manjim od 6,4, a koje menjaju afinitet<br />površine ka jonima arsena i metala. Rezultati ove doktorske disertacije pokazuju da se ispitivani adsorbent, MWCNT-NH<sub>2 </sub>, može koristiti za uklanjanje arsena i teških metala iz vode u prisustvu različitih anjona i da, svojim adsorpcionim karakteristikama, može konkurisati komercijalnim i ekonomski pristupačnim adsorbentima.</p> / <p>The subject of this doctoral thesis was the examination of the adsorption behaviour of As(III), and selected metals (Cu(II), Cd(II), Pb(II), Cr(VI)) on the amino-functionalized multiwalled carbon nanotubes, MWCNT-NH<sub>2</sub>, at four pH values (3, 4.5, 6, and 11) with different compositions of aqueous solutions (in the presence of chlorides, nitrates, sulphates and phosphates), in order to examine the possibilities of applying MWCNT-NH<sub>2</sub> in removal of arsenic and metal ions from aqueous solutions in relatively low concentration (0,01- 3mg L<sup>-1</sup>). The focus of this doctoral thesis was to establish the mechanism of adsorption process in given conditions. Arsenic and metal adsorption on MWCNT-NH<sub>2</sub> were best described with the pseudo-second order kinetic model, which assumes that adsorption can be attributed to the establishment of chemical reactions between the adsorbate, and the binding groups at the surface of adsorbent. The Weber - Morris diffusion model indicated that intercellular diffusion, although being a slower step than external diffusion, is not the only limiting step in the adsorption process, but also that the interactions of ions with the adsorbent surface binding sites, are responsible. In equilibrium, at different pH values, the adsorption could be described by the Langmuir and Freundlich adsorption models. The capacity and affinity of the adsorbent, and adsorption mechanism, were considerably determined by the pH value of the solution, either because of the characteristics of the surface of the investigated adsorbent depending on pH value, or the effect of the solution’s pH value on the chemical forms of arsenic and other metals. Investigation of the influence of the anion showed that the presence of chloride increased affinity of the surface of MWCNT-NH<sub>2</sub> to arsenic ions and to all metals in low concentration ranges, while presence of chlorides, nitrates, sulphates and phosphates had a positive impact on the affinity of the surface (2 or 8 times greater than for deionized water) MWCNT-NH<sub>2</sub> for Cu(II) in high concentration ranges. The smallest impact of anions to affinity of the surface to bond metals was noticed for chromium. The assumed mechanisms of removing arsenic and selected metals in the presence of anions include reactions of forming various kinds of outer- and inner-spheric complexes, ionic exchange, as well as electrostatic interaction which occur between positively charged surface of MWCNT-NH<sub>2</sub> and anions, for pH < 6.4, and which change affinity of the surface towards arsenic and metal ions. Results of this doctoral thesis show that the investigated adsorbent, MWCNT-NH<sub>2</sub>, can be used for the removal of arsenic and heavy metals from water, in the presence of different anions, and that with its adsorbent characteristic it can compete with commercially, and economically more affordable adsorbents.</p>
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Method development for the determination of residual pesticides and heavy metals in complex samples using modern preconcentration techniquesMusarurwa, Herbert 20 September 2019 (has links)
MSc (Chemistry) / Department of Chemistry / In this work, modern pre-concentration techniques, namely dispersive liquid-liquid micro-extraction (DLLME) and QuEChERS, were used to analyse pesticides and heavy metals in complex matrices. The work is divided into six papers.
In Papers 1, the recent developments and applications of DLLME during analysis of pesticides in food matrices were reviewed. The DLLME technique has captured the interests of many researchers in recent years. The major advantage, among others, of DLLME is miniaturisation in which the acceptor-to-donor ratio is reduced tremendously leading to high enrichment compared to other sample preparation techniques. In the present work, the different complex matrices where the DLLME technique has been employed for the analysis of pesticides are reviewed as well as the challenges associated with this technique.
Papers II reviewed the recent applications and developments of the QuEChERS technique during the analysis of pesticides in food matrices. QuEChERS is a versatile pre-concentration method whose application spans the whole breath of organic compounds. There are three common standard methods used during QuEChERS and these are the original QuEChERS, AOAC and the EN methods. In this paper, recent developments and applications of QuEChERS techniques in the analysis of pesticides in food samples were reviewed.
In Paper III, green pre-concentration techniques employed during analysis of pesticides were reviewed. Recently, the parameter of “greenness” during sample pre-concentration of pesticides in food matrices is as important as selectivity in order to avoid using large amounts of harmful organic solvents during sample preparation. Developing new green pre-concentration techniques is one of the key subjects in green chemistry in order to minimize the release of large volume of toxic organic solvents into the environment. Thus, to reduce the impact on the environment during trace analysis of pesticides in food matrices, new developments in pesticide pre-concentration have gone in three separate directions (which are reviewed in this paper): one is the search for more environmentally friendly solvents, the second one is miniaturization and the third one is the development of solvent-free pre-concentration techniques. Eco-friendly solvents such as supercritical fluids, ionic liquids and natural deep eutectic solvents have been developed for use as extraction solvents during pre-concentration of pesticides in food matrices. Also miniaturized pre-concentration techniques such as QuEChERS, dispersive liquid-liquid micro-extraction and hollow-fibre liquid phase micro-extraction have been used during trace analysis of pesticides in food samples as well as
solvent-free techniques such as solid phase micro-extraction and stir bar sorptive extraction. All these developments are geared to ensure that pesticide pre-concentration in food matrices is green and were reviewed in this paper.
The effect of vehicular emissions on the concentrations of selected heavy metals was investigated in Paper IV. The samples were pre-concentrated using DLLME prior to analysis with flame atomic absorption spectroscopy. Dithizone, chloroform and methanol were used as chelating agent, extraction solvent and dispersion solvent respectively during the DLLME technique. The pH of the sample was adjusted to around 8 using sulphuric acid or sodium hydroxide solution. The influential DLLME parameters, such as pH volume and type of extraction solvent, and voume of disperser solvent, were optimized prior to the application of the developed method to real samples (roadside dust, fruits and vegetables).
In Paper V, chromium speciation in fruits and vegetables was studied. The chromium in fruit and vegetable sample juices was pre-concentrated using DLLME prior to analysis with flame atomic absorption spectroscopy. Diphenylcarbazide (DPC) was used as a chelating agent in this study, and salting out of the complex from the aqueous medium into the organic phase was effected using sodium acetate. Chloroform and methanol were used as extraction and dispersion solvents respectively in the DLLME method for the determination of chromium (VI). For total chromium, the trivalent chromium was oxidised using acidified KMnO4 to hexavalent chromium before performing the DLLME technique. The concentration of chromium (III) was determined by finding the difference between total chromium and concentration of chromium (VI). The important parameters that influence the efficiency of the DLLME technique were also optimized using the univariate approach. After optimization, the developed method was applied to real samples.
In Paper VI, the concentration of malathion pesticide in fruits was determined using QuECHERS for pre-concentration and UV-Vis spectrophotometry for instrumental analysis. Acetonitrile was used as the extraction solvent and Z-sep+/PSA sorbent combination was used for sample clean-up. The acetonitrile extract from QuEChERS was then hydrolysed using KOH followed by reaction with acidified potassium bromate for colour development. The coloured product formed was then analysed using UV-Vis spectrophotometry. Among the fruits analysed, Oranges had no malathion residue in them. However, trace amounts of malathion, below WHO maximum allowable limits, were found in pears and apples. / NRF
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Spektroskopische Untersuchungen zur Komplexbildung von Cm(III) und Eu(III) mit organischen Modellliganden sowie ihrer chemischen Bindungsform in menschlichem Urin (in vitro)Heller, Anne January 2011 (has links)
Dreiwertige Actinide (An(III)) und Lanthanide (Ln(III)) stellen im Falle ihrer Inkorporation eine ernste Gefahr für die Gesundheit des Menschen dar. An(III) sind künstlich erzeugte, stark radioaktive Elemente, die insbesondere bei der nuklearen Energiegewinnung in Kernkraftwerken entstehen. Durch Störfälle oder nicht fachgerechte Lagerung radioaktiven Abfalls können sie in die Umwelt und die Nahrungskette des Menschen gelangen. Ln(III) sind hingegen nicht radioaktive Elemente, die natürlicherweise vorkommen und für vielfältige Anwendungen in Technik und Medizin abgebaut werden. Folglich kann der Mensch sowohl mit An(III) als auch Ln(III) in Kontakt kommen bzw. sie inkorporieren. Es ist daher von enormer Wichtigkeit, das Verhalten dieser Elemente im menschlichen Körper aufzuklären. Während makroskopische Vorgänge wie Verteilung, Anreicherung und Ausscheidung bereits sehr gut untersucht sind, ist das Wissen hinsichtlich der chemischen Bindungsform (Speziation) von An(III) und Ln(III) in Körperflüssigkeiten noch sehr lückenhaft.
In der vorliegenden Arbeit wurde daher erstmals die chemische Bindungsform von Cm(III) und Eu(III) in natürlichem menschlichem Urin (in vitro) spektroskopisch aufgeklärt und die gebildeten Komplexe identifiziert. Hierzu wurden auch grundlegende Untersuchungen zur Komplexierung von Cm(III) und Eu(III) in synthetischem Modellurin sowie mit den urinrelevanten organischen Modellliganden Harnstoff, Alanin, Phenylalanin, Threonin und Citrat durchgeführt und die noch unbekannten Komplexbildungskonstanten bestimmt. Abschließend wurden alle experimentellen Ergebnisse mit Literaturdaten und Vorherberechnungen mittels thermodynamischer Modellierung verglichen. Auf Grund der hervorragenden Lumineszenzeigenschaften von Cm(III) und Eu(III) konnte insbesondere auch die Eignung der zeitaufgelösten laserinduzierten Fluoreszenzspektroskopie (TRLFS) als Methode zur Untersuchung dieser Metallionen in unbehandelten, komplexen biologischen Flüssigkeiten demonstriert werden.
Die Ergebnisse dieser Arbeit liefern damit neue Erkenntnisse zu den biochemischen Reaktionen von An(III) und Ln(III) in Körperflüssigkeiten auf molekularer Ebene und tragen zu einem besseren Verständnis der bekannten, makroskopischen Effekte dieser Elemente bei. Darüber hinaus sind sie die Grundlage weiterführender in-vivo-Untersuchungen.
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