Dissertations / Theses on the topic 'And contaminants'
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Chałupniak, Andrzej. "Development of novel electrochemical and optical Lab-on-a-chip platforms for contaminants and biomarkers sensing." Doctoral thesis, Universitat Autònoma de Barcelona, 2017. http://hdl.handle.net/10803/457862.
Full textThe detection of hazardous contaminants requires special attention due to their possible toxicity, low concentration in real samples and, in most cases, an impossibility to perform detection by using such a specific approach as immunoassay. One of the approaches taking an important step towards easier detection of hazardous compounds is the use of Lab-on-a-chip platform. In Chapter 3, a novel, miniaturized microfluidic platform for the simultaneous detection and removal of polybrominated diphenyl ethers (PBDEs) was developed. The platform consists of a polydimethylsiloxane (PDMS) microfluidic chip for the immunoreaction step, a PDMS chip with an integrated screen-printed electrode (SPCE) for detection, and a PDMS-reduced graphene oxide (rGO) chip for physical adsorption and subsequent removal of PBDE residues. The detection was based on competitive immunoassay-linked binding between PBDE and PBDE modified with horseradish peroxidase (HRP-PBDE) followed by the monitoring of enzymatic oxidation of o-aminophenol (o-AP) by using square wave anodic stripping voltammetry (SW-ASV). PBDE was detected with good sensitivity and a limit of detection similar to that obtained with a commercial colorimetric test (0.018 ppb), but with the advantage of using lower reagent volumes and a reduced analysis time. In order to design a detection system suitable for toxic compounds such as PBDEs, a reduced graphene oxide–PDMS composite has been developed and optimized to obtain increased adsorption (based on both the hydrophobicity and π–π stacking between rGO and PBDE molecules) compared to those of non-modified PDMS. This system can be easily applied to detect any analyte by using the appropriate immunoassay and it supports operation in such complex matrices as seawater. In Chapter 4, a LOC device for the simultaneous preconcentration and detection of heavy metals was developed. This device consists of a screen-printed carbon electrode, a PDMS chip, and a GO-PDMS chip. The GO-PDMS chip was fabricated and the most crucial factors were optimized, including the concentration of GO and the concentration of the curing agent. It was found that the adsorption ability is inversely proportional to the PDMS catalyser (curing agent) concentration in the composite and proportional to the GO concentration. The mechanism of adsorption is based on surface complexation, where oxygen active groups of negative charge can bind with such bivalent metals as Pb. The highest adsorption was obtained in pH=7. The GO-PDMS has a relatively big large adsorption capacity, as even the samples >500 ppb are nearly fully adsorbed, taking into account that such a concentration is very high. The desorption process was optimized as well. Thanks to this, previously adsorbed metals can be released and detected in square wave anodic stripping voltammetry. The limit of detection of this technique (using screen-printed electrodes) was 0.5 ppb for Pb. This means that by using a preconcentration GO-PDMS platform, a lower amount of Pb can be quantified because preconcentrated samples showed a current up to 30 times higher than that of non-preconcentrated one. This platform can be used for improved heavy metal sensing and also for its removal.
Borrull, Callau Josep. "Presència de compostos orgànics prioritaris i emergents en aigües destinades al consum humà." Doctoral thesis, Universitat Rovira i Virgili, 2021. http://hdl.handle.net/10803/671552.
Full textLos contaminantes orgánicos son sustancias químicas con el potencial de causar efectos adversos al medio ambiente y / o la salud humana. Debido al uso cada vez más elevado de sustancias químicas y su emisión continuada al medio ambiente, estas se pueden considerar como pseudo-persistentes, convirtiendo en una prioridad el monitoreo de su presencia en el medio ambiente. Uno de los aspectos que está suscitando una mayor preocupación es el control de los contaminantes orgánicos en el medio acuático, ya que puede afectar de manera significativa a su calidad. En este sentido, el objetivo principal de esta Tesis es el desarrollo de metodología analítica basada en la cromatografía líquida acoplada a la espectrometría de masas en tándem, utilizando un analizador de triple cuadrupolo, para la determinación de ciertos contaminantes orgánicos, tanto prioritarios como emergentes, en muestras de agua. Una vez la metodología ha sido desarrollada y validada, ha sido aplicada al análisis de muestras de agua del río Ebro y en muestras recogidas en una ETAP. De esta manera se ha podido evaluar la presencia de estos contaminantes en estas aguas, así como la efectividad de los diferentes tratamientos aplicados en esta ETAP para la eliminación de estos contaminantes.
Organic pollutants are chemicals with the potential to cause adverse effects to the environment and / or human health. Due to the increasing use of chemical substances and their continuous release into the environment, these can be considered as pseudo-persistent, making monitoring their presence in the environment a priority. One of the aspects that is causing the greatest concern is the control of organic pollutants in the aquatic environment, as it can significantly affect its quality. In this sense, the main objective of this Thesis is the development of analytical methodology based on liquid chromatography coupled to tandem mass spectrometry, using a triple quadrupole analyzer, for the determination of certain organic pollutants, both priority and emerging, in water samples. Once the methodology has been developed and validated, it has been applied to the analysis of water samples from the Ebro river and in samples collected in an ETAP. In this way, the presence of these pollutants in these waters has been evaluated, as well as the effectiveness of the different treatments applied in this ETAP for the elimination of these pollutants.
Conrad, Anne. "Exposure of the oligochaete Lumbriculus variegatus to sediment associated contaminants : influence of contaminant properties." Thesis, University of Reading, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.269915.
Full textFujii, Reinaldo Keiji. "Avaliação da qualidade do ar em duas estações do metrô de São Paulo." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/6/6132/tde-15092011-112332/.
Full textObjective. Compare the air quality outdoors with the indoors environment at Clínicas and Praça da Sé Stations of the São Paulo Subway, measuring the quantity and quality of the existing microbiological and atmospheric contaminants. The purpose of this study is to promote the knowledge of factors related to the air quality and the health and hygiene conditions in these places, contributing to the improvement of the quality of life of employees and users of the system. Methods. The samples were taken from July to November 2005. The fungi were taken by one-stage Andersen impactor with aspiration volume of 28 l/min for a period of 10 minutes per sample, making use of Agar Sabouraud Dextrose at 4 per cent for the culture. The quantification and identification are done by the analysis of slides with the microbiological material in an optical microscope, colored with lactofenol blue. For the nitrogen dioxide, a passive diffuser was used with triethanolamine as absorbing substance and the analysis was done by spectrophotometry, the passive diffuser used to evaluate the concentration of benzene is the membrane type with activated carbon as absorbing substance making use of gas chromatography analysis. The exposure period for these samplers was 30 days. The PM10 was measured with a continuous monitor, with direct reading. This equipment uses fibreoptic sensors for the identification of the size and concentration of the particles which are sucked by a diaphragm pump, passing through a measuring chamber which also measures the temperature and the air humidity. Two pieces of this equipment were installed in each station for a period of seven days. Results. The studies indicate the presence of ordinary fungi with the prevalence of Cladosporium sp (52 per cent ), Alternaria sp (17 per cent ) and Penicillium sp (13 per cent ) in similar proportions both indoors and outdoors. The indoor average concentration of NO2 was 69,5g/m³. These values are similar to the outdoor x results obtained with the equipment for Differential Optical Absorption Spectroscopy (DOAS) and the values measured by CETESB control station, located at FSP/USP. The values found for benzene ranged from 3,8 to 6,2g/m³, indicating an average of 5,0g/m³. The PM10 indicated high values with an average, at Clínicas Station, of 312,4 g/m³ measured in the platform and 243,9 g/m³ in the mezzanine. At Praça da Sé Station the concentration on the platforms was 150,9 g/m³ for line 1 and 124,2 g/m³ for line 3. Conclusions. The present study permitted the assessment and comparison of the environmental pollution levels inside and outside the stations. The verification of the predominance of common fungi in the air doesn\'t indicate the absence of risks for the human health, because it impact depends on the exposed individuals\' susceptibility. The concentration of NO2 and benzene found in the internal and external atmosphere are of same order of greatness, what indicates that these pollutants have the same origin source. The high concentration of PM10 represents a larger concern. This pollutant it should be evaluated the composition of the found material and his toxicity degree
Falcão, Dantas Renato. "Ozonation of Emergent Contaminants." Doctoral thesis, Universitat de Barcelona, 2007. http://hdl.handle.net/10803/1534.
Full textIn this work, the ozonation of emergent contaminants represented by pharmaceuticals (Sulfamethoxazole and Bezafibrate) and surfactants (Quaternary Ammonium Compounds) was studied. Results in terms of target compound degradation and mineralization along with the biodegradability and toxicity assessment of formed intermediates are presented. Moreover, a previous study about the suitability of the combination ozonation-Sequencing Batch Biofilm Reactor (SBBR), using the model compound 4-chlorophenol, is shown.
The preliminary runs aimed to assess the mineralization of 100 and 200 mg L-1 4-chlorophenol (4-CP) solutions by ozonation and ozonation-biological treatment (SBBR). The experimental results showed that with an ozone flow rate of 5.44 and 7.57 g h-1, 4-CP was completely removed from the solution in 15 and 30 minutes of ozonation, respectively. By the other hand, at the 4-CP abatement time, on average only 26 % of total organic carbon (TOC) removal was achieved. The biodegradability (BOD5/COD) of the pre-ozonated solutions increased from 0 until a range between 0.2-0.37. The combination of ozonation and aerobic biological treatment in an aerobic sequencing batch biofilm reactor (SBBR) gave an abatement of more than 90 % of the initial TOC.
The Quaternary Ammonium Compounds (QACs) ozonation was carried out in order to assess the mineralization potential of ozonation processes for this class of compounds. To perform this study, the QACs 16-BAC (Benzyl-dimethyl-hexadecylammonium-chloride) and 18-BAC (Benzyl-dimethyl-stearylammonium-chloride) were treated by ozonation at different O3 dosage. According to experimental results, from an initial TOC concentration of 50 mg L-1, 90 minutes of ozonation reached at most 50% of mineralization at the used conditions (ozone flow rate 7.57 g h-1). In order to observe the mineralization of QACs by means of photo-Fenton, the runs were carried out with the same QAC concentration used in ozonation runs. Besides, two different lamps were used (UV and Xe). According to experimental results, after 90 minutes of treatment, the photo-Fenton process achieved up to 80% of mineralization when the UV lamp was used. The efficiency of the photo-Fenton with Xe lamp was lower.
To carry out the study of the sulfamethoxazole (SMX) ozonation, 200 mg L-1 SMX solutions were treated by ozonation at different pH. Results showed that ozonation was proved to be an efficient method to degrade sulfamethoxazole. After 15 minutes of ozonation (corresponding dose = 0.4 g of ozone L-1), the complete antibiotic abatement was almost achieved with just 10 % of mineralization. The biodegradability and toxicity of the ozonation intermediates were also studied. A biodegradability enhancement (increment of BOD5/COD ratio) from 0 to 0.28 was observed after 60 min of ozonation. The acute toxicity of the intermediates was followed by the Microtox® test and the toxicity profile showed a slight acute toxicity increment in the first stage of ozonation. The second order kinetic constants for the ozonation of the SMX in an order of magnitude of 105 L mol-1 s-1 were also determined for pH 5 and 7.
Concerning the Bezafibrate (BZF) ozonation, the results showed that ozonation is an efficient method to degrade BZF: after 10 minutes of treatment (corresponding to a dose of 0.73 mmoles L-1 of ozone), the complete BZF abatement is achieved, starting from an initial concentration of 0.5 mmoles L-1. However, only a small part of the substrate is mineralized. The identification of main intermediates, attempted by HPLC-MS technique, indicates that the oxidation of BZF develops through both the hydroxylation of the aromatic ring and the attack of ozone on the unchlorinated aromatic one. The assessment of by-products biodegradability and acute toxicity demonstrates that ozonation is a suitable technique to improve the biodegradability and reduce the toxicity of waters containing BZF.
Lu, Qian. "Contaminants in food stuffs." Thesis, Liverpool John Moores University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388586.
Full textRönn, Monika. "Environmental Contaminants and Obesity." Doctoral thesis, Uppsala universitet, Arbets- och miljömedicin, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-209807.
Full textLommatzsch, Martin. "Hydrocarbons as food contaminants:." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-233297.
Full textBressy, Fernanda Costa. "Determinação de micromutrientes em amostras de tomates por tecnicas espectroanaliticas." reponame:Repositório Institucional da UFBA, 2011. http://www.repositorio.ufba.br/ri/handle/ri/10810.
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FAPESB
A cultura do tomate tem ocupado lugar de destaque em todo mundo. O aumento na produtividade da hortaliça provocou um aumento na utilização de insumos agroquímicos, fazendo-se necessário o monitoramento de elementos essenciais e elementos potencialmente contaminantes. Neste trabalho foram determinadas as concentrações de elementos essenciais e elementos potencialmente contaminantes em tomates das espécies caqui, itália e cereja, em cultivos convencional e orgânico, em fase inicial e final de maturação. As amostras foram coletadas em vários estabelecimentos da cidade de Salvador, Bahia, Brasil visando avaliar as diferenças nas concentrações entre os estágios de maturação, tipo de cultivo e espécie, no fruto inteiro e em suas partes (casca, polpa e semente). Os elementos estudados foram Al, Ba, Cd, Cu, Co, Cr, Fe, Mn, Ni, Pb, Sb, Se, Sn, Sr, V e Zn. Após otimização do procedimento de preparo, as amostras foram submetidas à digestão em forno de micro-ondas com cavidade, usando a mistura de 3,5 mL de ácido nítrico concentrado destilado, 3,5 mL de água ultra pura e 1,0 mL de peróxido de hidrogênio. Para determinação dos elementos foram empregadas as técnicas espectrometria de emissão óptica com plasma indutivamente acoplado (ICP OES) e espectrometria de massas com plasma indutivamente acoplado (ICP-MS). Através dos resultados obtidos, foi possível comparar a concentração dos elementos estudados nos estágios de maturação, cultivo e espécies dos tomates analisados. Quanto ao estágio de maturação, os tomates em estágio final de maturação apresentaram maiores valores de concentração para a maioria dos elementos medidos, nas três espécies estudadas. Na comparação quanto ao tipo de cultivo, as amostras provenientes do manejo orgânico apresentaram maiores valores de micronutrientes e menores de elementos com potencial contaminante quando em comparação com as amostras de tomates oriundas de cultivo convencional. Em relação às diferentes espécies estudadas, observou-se que as amostras de tomate contribuem significativamente para a ingestão diária recomendada de Cr, Cu e Mn, sendo a espécie caqui a que mais contribui para a ingestão de Cu, a itália de Cr e a cereja de Mn. As concentrações dos elementos potencialmente tóxicos, encontradas para as amostras das três espécies de tomate, estão abaixo dos teores regulamentados pela ANVISA. Palavras-Chave: toma
Salvador
Núñez, Marcé Mireia. "Emerging organic contaminants in aquatic organisms." Doctoral thesis, Universitat Rovira i Virgili, 2017. http://hdl.handle.net/10803/456825.
Full textEsta tesis doctoral se centra en el desarrollo de nuevos métodos analíticos para determinar diferentes contaminantes orgánicos emergentes, como productos farmacéuticos de consumo generalizado, medios yodados de contraste para rayos-X (otro grupo de productos farmacéuticos empleados en medicina de diagnóstico) y un grupo de edulcorantes de alta intensidad en organismos acuáticos. Para ello se evaluaron dos técnicas de extracción (extracción con líquidos presurizados y QuEChERS) para extraer los compuestos seleccionados y también se ensayaron diferentes limpiezas. La determinación se realizó mediante cromatografía de líquidos acoplada a espectrometría de masas. Además, se realizó un estudio ecotoxicológico en la especie Gammarus pulex, donde se evaluó la toxicidad del triclosán para esta especie y, además, se estudiaron poblaciones procedentes de diferentes ambientes con diferentes grados de contaminación para determinar si su resistencia era similar o no.
This Doctoral Thesis focuses on the development of new analytical methods to determine different emerging organic contaminants such as pharmaceuticals of widespread consumption, iodinated X-ray contrast media (another group of pharmaceuticals employed in diagnostic medicine), and a group of high-intensity sweeteners, in aquatic organisms. To do so two extraction techniques (pressurised liquid extraction and QuEChERS) were evaluated to extract the selected compounds and different clean-ups were also tested. The determination was perfomed with liquid chromatography coupled with mass spectrometry. Moreover, another objective is to conduct an ecotoxicological study in the amphipod species Gammarus pulex, where the toxicity of triclosan to this species was evaluated. Moreover, populations that come from different environments with different degrees of pollution were evaluated in order to establish whether their resistance was similar or not.
Hom, Díaz Andrea. "Degradation of pharmaceutical compounds by microalgae: photobioreactor wastewater treatment, biomass harvesting and methanization." Doctoral thesis, Universitat Autònoma de Barcelona, 2016. http://hdl.handle.net/10803/390962.
Full textEmerging contaminants (ECs) are a wide range of organic compounds detected in many environmental compartments that have raised an increasing interest in the scientific community due to their ubiquitous presence in the environment and their difficult degradation. Even though their environmental concentration is usually in the range of ng/L to μg/L, they still represent a threat to human health and environment since they are excreted with urine and faeces either as active substances or metabolites, because they are not completely assimilated. Among emerging contaminants, endocrine disrupting compounds (EDCs) and pharmaceutical active compounds (PhACs) are of major concern. It is widely accepted that the main source to the environment are the effluents of wastewater treatment plants (WWTP), where conventional activated sludge treatments are not able to degrade most of them being able to reach surface, groundwater and subsequently, drinking water. Therefore, alternative treatments should be found. One of those alternatives might be the use of microalgae by taking advantage of their capacity for wastewater treatment removing the nutrients contained in the wastewater and further microalgal biomass conversion into biofuels. The present thesis assesses different factors related to microalgal degradation of emerging contaminants and wastewater treatment. As well as the study of one of the major bottlenecks on microalgal systems, the harvesting, which has the advantage to clarify the treated wastewater and concentrate the microalgal biomass for further biogas production. Pure microalgal cultures and real microalgal effluents have been considered. First of all, individual degradation of two estrogenic compounds has been studied. The two estrogenic compounds evaluated have been recently incorporated in the priority substances in the Water Framework Directive: 17α-ethinylestradiol (EE2) and 17β- estradiol (E2). Their degradation by Chlamydomonas reinhardtii and Pseudokirchneriella subcapitata pure cultures at laboratory scale conditions has been monitored. To obtain further insights in the mechanism of degradation the transformation products have been identified. Moreover, the removal of a mixture of 10 PhACs (9 antibiotics and an antidepressant) has also been assessed in pure microalgal cultures at laboratory scale conditions. Transformation products from three chosen PhACs have been identified. One of the antibiotics, ciprofloxacin, was further evaluated. The removal mechanisms have been studied in real algal ponds in both, laboratory and pilot scale reactors. On the other hand, an algal photobioreactor (PBR) treating urban wastewater has been designed and operated during 6 months. Its performance has been monitored and different operating conditions have been tested. Furthermore, PhACs removal has been evaluated during the steady state and microbial diversity has been identified. The estrogenic compound E2 removal in the PBR has been studied. The importance of microalgal harvesting has been highlighted in the thesis. Three different harvesting techniques (i.e., natural sedimentation, coagulation-flocculation and the novel technique of co-pelletization using Trametes versicolor fungus) have been evaluated using two real microalgal effluents and a pure Chlamydomonas reinhardtii suspension. Finally, methanization of exhausted biomass has been conducted. Prior the anaerobic digestion process microalgal biomass has been submitted to an enzymatic pretreatment for its cell wall solubilisation. Specific and non-specific enzymes have been tested as well as the synergistic effects between an enzymatic mixture. The study is completed valorising fungal biomass coming from the treatment of effluents.
Neale, Jennifer Carroll Carpenter. "Persistent organic contaminants and contaminant-induced immune and health alterations in the harbor seal, Phoca vitulina /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2004. http://uclibs.org/PID/11984.
Full textHwang, Haejo. "Contaminant body residues in Chironomus riparius to assess acute and chronic toxic effects of environmental contaminants /." The Ohio State University, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=osu1488202171194645.
Full textRoig, Montserrat Neus. "Aplicació de tècniques ecotoxicològiques en diferents matrius ambientals. Viabilitat i complementarietat." Doctoral thesis, Universitat Rovira i Virgili, 2012. http://hdl.handle.net/10803/96291.
Full textEl objetivo general de esta tesis ha sido evaluar la aplicación de bioensayos específicos y un bioensayo estandardizado genérico en distintas matrices ambientales. De este modo se pretende complementar la información obtenida con los análisis químicos para poder establecer un mejor diagnóstico ambiental. Se han analizado metales y compuestos orgánicos en muestras de distintos compartimentos ambientales. Para evaluar la ecotoxicidad de muestras de agua dulce se ha escogido el alga Pseudokirschneriella subcapitata, mientras que para muestras de suelos y residuos orgánicos se han escogido plantas de interés agrícola como son Allium cepa, Raphanus sativus y Lolium perenne. Por último, se han realizado tests in Vitro de toxicidad humana para evaluar la toxicidad de las partículas PM10 del aire, con cultivos de células pulmonares (línea A549). En todos los casos se ha realizado un ensayo ecotoxicológico con la bacteria luminescente Vibrio fischeri, para evaluar su idoneidad en las distintas matrices ambientales. Los resultados han demostrado que el uso de bioensayos específicos en distintas matrices ambientales puede suponer una buena herramienta de ‘’screening’’ para completar la información obtenida de los análisis químicos, que realizados de forma individual, pueden estimar erróneamente la toxicidad real de las muestras ambientales. Además, se ha observado que el bioensayo con Vibrio fischeri presenta buena complementariedad con otros ensayos más específicos de cada matriz ambiental, además de ser muy sensible a la presencia de contaminantes en aguas y sedimentos fluviales, lodos de depuradora y PM10 del aire.
Uhlman, Kristine, Channah Rock, and Janick Artiola. "Arizona Drinking Water Well Contaminants." College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2009. http://hdl.handle.net/10150/156930.
Full textThis short fact sheet is taken from "Arizona Well Owner's Guide to Water Supply" currently in print. We plan to complete part 2 of this fact sheet by the end of July, 2009. Please note that the text has already been incorporated into the eXtension Community of Practice web page - - I am the author for the COP/Drinking Water group text on chemistry of naturally occurring water contaminants.
Arizona well water is often contaminated with elevated concentrations of naturally occurring constituents that are a human health concern. This short fact sheet is the first in a two-part series about what naturally occurring contaminants may be found in your water supply well and includes a brief discussion on environmental pollutants that originate from land use activities. If you own a well in Arizona, you have the sole responsibility for checking to see if your drinking water is contaminated. Arizona state law does not require private well owners to test or treat their water for purity. The second part of this series outlines what to sample for and how to understand your analytical results.
Lampa, Erik. "Mixture Effects of Environmental Contaminants." Doctoral thesis, Uppsala universitet, Arbets- och miljömedicin, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-237690.
Full textLeifert, Carlo. "Contaminants of plant tissue cultures." Thesis, University of Nottingham, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.282645.
Full textMormede, Sophie. "Contaminants in deep water fish." Thesis, University of Glasgow, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.392611.
Full textAranha, Taise Suéllen de Castro Porto 1987. "Desenvolvimento e validação de método para determinação de cádmio e chumbo em carnes de caprinos, ovinos e avestruz." [s.n.], 2015. http://repositorio.unicamp.br/jspui/handle/REPOSIP/249400.
Full textDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química
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Resumo: O objetivo principal deste projeto de pesquisa consistiu em desenvolver e validar um método para a determinação de cádmio e chumbo, pela técnica de Espectrometria de Absorção Atômica com Forno de Grafite (GF AAS), nas matrizes rim e fígado de caprinos, ovinos e avestruz. Este trabalho justifica-se pela importância do monitoramento do teor de contaminantes inorgânicos em produtos alimentícios, uma vez que a exposição a estes pode afetar os seres humanos e os animais, devido ao seu potencial tóxico e seus efeitos cumulativos. Além disso, o controle de resíduos em alimentos também é relevante devido às exigências do mercado, como o atendimento às legislações vigentes para a comercialização interna e exportação de produtos. Para o preparo de amostra adotou-se a amostragem em suspensão, um método particularmente atrativo, uma vez que não requer um pré-tratamento químico agressivo, é menos susceptível a contaminação e perda do analito, além de que padrões aquosos podem ser usados para a calibração, facilitando as análises de rotina. Os fatores envolvidos nesta etapa, bem como os parâmetros instrumentais foram otimizados através de planejamentos experimentais. Desta forma, o preparo das amostras de carne foi conduzido à temperatura ambiente, a partir da hidratação de 500 mg da amostra (in natura ou liofilizada), seguida de solubilização com 500 ?L de TMAH 25% (m/v), e avolumando-se para 10,0 mL com água desionizada. As análises foram realizadas por Espectrometria de Absorção Atômica com Forno de Grafite, adotando-se temperaturas de pirólise e de atomização iguais a 500 e 1500 ºC, associadas ao uso de uma combinação de 5 ?g Pg(NO3)2 e 3 ?g de Mg(NO3)2 como modificador químico, para a determinação de Cd. Por sua vez, para a quantificação de Pb, empregaram-se temperaturas de pirólise e de atomização de 1000 e 2000 ºC, com 10 ?g Pg(NO3)2 + 6 ?g de Mg(NO3)2 como modificador químico combinado. Visando atender às legislações nacionais e internacionais, a validação do método foi conduzida em níveis de concentrações específicos, relacionados ao teor máximo de contaminantes (TMC), e os critérios de aceitabilidade das figuras de mérito seguiram as recomendações da comunidade européia (CE/657, CE/333) e do Mercosul (Mercosul/GMC/RES n. 57/94)
Abstract: The main objective of this project was to develop and validate a method for the determination of cadmium and lead, by Graphite Furnace Atomic Absorption Spectrometry (GF AAS), in caprines, ovines and ostrich kidney and liver. This work is justified by the importance of monitoring the content of inorganic contaminants in food products, since exposure to them can affect humans and animals due to their toxic potential and their cumulative effects. In addition, the residue control in food is also relevant for commercial reasons, such as attending the existing laws for internal commerce and for exportation. For sample preparation was adopted slurry sampling, a particularly attractive method because it does not require an aggressive chemical pretreatment, is less susceptible to contamination and loss of analyte, and aqueous standards can be used to calibration, facilitating the routine analysis. The factors involved in this treatment, as well as the instrumental parameters, were optimized using experimental designs. In the proposed method, 500 mg meat sample (fresh or lyophilized) was previously hydrated and treated using 500 ?L of tetramethylammonium hydroxide solution (TMAH) which provided stable and homogeneous slurry at room temperature in less than 10 min. The volume was brought up to 10 mL with deionized water. Analyses were performed by GF AAS, adopting pyrolysis and atomization temperatures equal to 500 and 1500 ° C, respectively, associated with the use of 5 ?g Pg(NO3)2 and 3 ?g de Mg(NO3)2 as a chemical modifier for the determination of cadmium. In turn, for the lead quantification, pyrolysis and atomization temperatures equal to 1000 and 2000 °C were employed, respectively, and as chemical modifier 10 ?g Pg(NO3)2 and 6 ?g de Mg(NO3)2, containing triton X-100, was used. In order to comply with national and international legislation, the method validation was conducted on specific concentrations levels, related to the maximum contaminants levels (ML), and the criteria of acceptability of figures of merits followed the European Community and MERCOSUL recommendations
Mestrado
Quimica Analitica
Mestra em Química
Nieto, Cebrián Antonio. "Emerging organic contaminants in sewage sludge." Doctoral thesis, Universitat Rovira i Virgili, 2010. http://hdl.handle.net/10803/9048.
Full textLos métodos desarrollados se basan en la extracción presurizada con solventes (PLE) y, debido a la polaridad de estos contaminantes, la cromatografia de líquidos. Como técnicas de detección se han utilizado la espectrometría de masas (con quadrupolo y tiempo de vuelo como analizadores) y la espectrometría de masas en tandem (con triple quadrupolo como analizador) utilizando la interfase de electrospray.
A parte del desarrollo de los métodos para la determinación de fármacos, hormonas y compuestos de cuidado personal, se han analizado muestras de dos plantas de tratamiento de aguas residuales de la zona de Tarragona. Se han obtenido resultados de la presencia de estos compuestos en lodos de depuradora que hasta la fecha no existían sobre las muestras de esta zona.
The scope of this thesis is to develop analytical methods to determine a group of pharmaceuticals and personal care products included in the list of so called "emerging organic contaminants".
The methods are based on pressurized liquid extraction as extraction technique and due to the polarities of these contaminants, liquid chromatography was the selected separation technique. Because the low concentration of these contaminants in sewage sludge, sensitive and selective detection technique have to be used such as mass spectrometry (with quadruople or time of flight analyzers) and tandem mass spectrometry (with triple quadrupole analyzer) using in all cases the electrospray interface.
The methods developed have been used to monitor several groups of pharmaceuticals and personal care products from sewage sludge from two different sewage treatment plants. The samples have been collected in Tarragona, where no studies related to the control of these compounds have been done.
Bergua, Canudo José Francisco. "Nanobiosensors for contaminants detection in water." Doctoral thesis, TDX (Tesis Doctorals en Xarxa), 2020. http://hdl.handle.net/10803/670394.
Full textEsta tesis tiene como objetivo desarrollar biosensores para el monitoreo ambiental. Primero, se ha desarrollado un biosensor colorimétrico basado en lateral flow strips (LFS) para la detección y cuantificación de Escherichia coli como indicador fecal universal. En este caso, nanopartículas de oro (AuNP) se utilizan como transductores ópticos y anticuerpos policlonales como elementos de bioreconocimiento para capturar, marcar e indicar la presencia de la bacteria. Paralelamente, se ha desarrollado un sistema de filtración para mejorar la sensibilidad de las LFS. La optimización del flujo de la muestra a través de los diferentes materiales ha realizado mediante una técnica innovadora basada en el seguimiento del flujo de la bacteria bioluminiscente Aliivibrio fischeri, similar en tamaño y forma a E. coli. Finalmente, estos LFB se han probado con muestras de agua de ríos y aguas residuales, mostrando una sensibilidad similar y buena reproducibilidad y selectividad en todos los casos. En segundo lugar, se ha desarrollado un biosensor de toxicidad bioluminiscente para la detección y cuantificación de pesticidas en muestras de agua. En particular, Aliivibrio fischeri, una bacteria bioluminiscente, se ha utilizado como elemento de bioreconocimiento y transductor porque aumenta y disminuye la bioluminiscencia de acuerdo con la concentración de compuestos tóxicos en las muestras de agua. Además, el óxido de grafeno (GO) se ha utilizado como un potenciador del crecimiento no específico para promover el crecimiento bacteriano y aumentar la sensibilidad del sistema al detectar parcialmente la bioluminiscencia emitida por A. fischeri. La detección y cuantificación de la bioluminiscencia se realizó con un teléfono móvil que permite una evaluación de la toxicidad del agua de forma portátil, más barata, y más fácil de usar que los estándares en los laboratorios. En tercer lugar, se ha desarrollado una plataforma portátil basada en un teléfono móvil para realizar ensayos que requieren una detección óptica, incluyendo ensayos colorimétricos, fluorescentes y bioluminiscentes. Esta plataforma se ha utilizado para llevar a cabo y analizar pruebas ELISA estándar basadas en resultados colorimétricos para la detección de la inmunoglobulina humana y una proteína del coronavirus. Además, el sistema permite realizar un seguimiento de la agregación de AuNPs en función del color de la solución. Por otro lado, la plataforma se ha utilizado para detectar y cuantificar quantum dots (QD) y otros indicadores fluorescentes (por ejemplo, fluoresceína), así como para realizar pruebas ELISA fluorescentes basadas en estos transductores. Además, la plataforma permite realizar lecturas bioluminiscentes con aplicaciones como el análisis de la toxicidad del agua. Finalmente, la plataforma es útil para el cultivo de bacterias, mediciones de turbidez y detección de resistencia a antibióticos.
This thesis aims to develop biosensing tools for environmental monitoring. First, a colorimetric lateral flow biosensor (LFB) has been developed for the detection and quantification of Escherichia coli as a universal fecal indicator. Gold nanoparticles (AuNPs) are used as optical transducers and polyclonal antibodies as the biorecognition elements to capture, tag and indicate the presence of the bacteria. In parallel, a filtration system has been developed to improve the sensitivity of the LFBs. The optimization of the flow properties of the different lateral flow materials has been done by an innovative technique based on the tracking of the flow of the bioluminescent bacteria Aliivibrio fischeri, similar in size and shape to E. coli. Eventually, these LFBs have been tested with river and sewage waters, showing similar sensitivity and good reproducibility and selectivity in all the cases. Second, a bioluminescent toxicity biosensor has been developed for the detection and quantification of pesticides in water samples. In particular, Aliivibrio fischeri, a bioluminescent bacteria, has been used as the biorecognition element and the transducer because it turns up and down bioluminescence according to the concentration of toxic compounds within the water samples. Besides, graphene-oxide (GO) has been used as a non-specific growth enhancer to promote bacterial growth and increase the sensitivity of the system by partially screening the bioluminescence emitted by A. fischeri. The detection and quantification of the bioluminescence has been performed by a smartphone that allows for a cheaper, more user friendly, and portable water toxicity assessment. Third, a smartphone-based portable platform has been developed for the performance of optical sensing, including colorimetric, fluorescent, and bioluminescent assays. This platform has been used to perform and read standard ELISA tests based on colorimetric outputs for human IgG and coronavirus detection. In addition, the system allows for tracking AuNPs aggregation based on the color output of the solution. On the other hand, the platform has been used to detect and quantify quantum dots (QDs) and other fluorescent reporters (i.e. fluorescein), as well as performing fluorescent ELISA tests based on these transducers. Next, the platform allows for bioluminescent readouts with applications in toxicity analysis. Eventually, the platform is suitable for bacteria culture, turbidity measurements, and drug screening for antibiotic resistances assessment.
Hassinger, Elaine, and Jack Watson. "Health Effect of Drinking Water Contaminants." College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 1998. http://hdl.handle.net/10150/146310.
Full textChemical contaminants occur in drinking water supplies throughout the United States, ranging from barely detectable amounts to levels that could possibly threaten human health. Determining the health effects of these contaminants is difficult, especially since researchers are still learning how chemicals react to the damaged cells. This publication addresses the issue of chemical contaminants in drinking water, topics include; acute and chronic health effects, setting standards, and treatment techniques.
Yates, Kyari. "Bioavailability of organic contaminants in sediments." Thesis, Robert Gordon University, 2008. http://hdl.handle.net/10059/588.
Full textOesterling, Elizabeth Grace. "ENDOTHELIAL CELL DYSFUNCTION BY ENVIRONMENTAL CONTAMINANTS." UKnowledge, 2008. http://uknowledge.uky.edu/gradschool_diss/642.
Full textSu, Jia S. M. Massachusetts Institute of Technology. "Biological and particulate contaminants in interfaces." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/120444.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (pages 63-70).
The transport of biological, chemical, or particulate contaminants shapes disease transmission, chemical spills, climate, ecology, and bio-hazard risks. Yet, little is understood on the mechanisms controlling droplet formation and selection of droplet sizes and contamination levels from a contaminated water bulk. Bubbles play a critical role in shaping this transfer of chemicals, particulates, and biological organisms from water to air. They surface, and eventually burst, emitting myriads of droplets into the air. Despite recent progress in our understanding of bubble formation and bursting at the air-water interface, the factors selecting the loads that they carry and emit into the air remain unknown in part due to limitation in direct measurements. In this thesis, we discuss a method of direct visualization and quantification of particulates contained in contaminated bubble films at interfaces. The calibration of this method is key to progress in our understanding of particulate transport from water to air. In particular, although our method allows to reveal contaminants within films via the appearance of spots, the exact link between the size of such spots and the size of the original particles or organisms, their shape, wetting, and the size of the film remain unexplored. In this thesis, we performed a series of systematic measurements and calibrations using bacteria, particles, and rods of various sizes and wetting properties to calibrate the spot sizes observed on contaminated bubbles and films. We rationalized the dependencies observed using a combination of optical ray-tracing and modelling of film distortion in the presence of contaminant. Our results have important implications for in situ study of particles and bacterial communities within large scale complex interfaces.
by Jia Su.
S.M.
Vilo, Muñoz Claudia Andrea. "Understanding Microbial Biodegradation of Environmental Contaminants." Thesis, University of North Texas, 2015. https://digital.library.unt.edu/ark:/67531/metadc801956/.
Full textCoelho, Sónia Dias. "Human exposure pathways to environmental contaminants." Doctoral thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/17787.
Full textOs humanos estão permanentemente expostos a vários contaminantes ambientais que têm sido produzidos pela indústria química ao longo das últimas décadas. Para além do contacto direto com produtos onde estes contaminantes são aplicados, a exposição ocorre principalmente porque estes químicos se libertam destes materiais e acumulam-se no ambiente, tornando-se desta forma disponíveis para serem consumidos involuntariamente pelos humanos. Durante muito tempo a alimentação foi considerada como a principal via da exposição dos humanos a diversas classes de contaminantes, incluindo os poluentes orgânicos persistentes (POPs) e metais tóxicos. No entanto, a exposição através do pó em ambientes interiores surgiu como uma importante via de exposição, principalmente porque estes contaminantes se acumulam no pó e devido ao facto das pessoas passarem grande parte do seu tempo em ambientes interiores. Na presente tese, foi estudada a presença de várias classes de contaminantes ambientais em amostras de duplicados de dieta e amostras de pó doméstico, de forma a caracterizar a exposição dos humanos através da ingestão de alimentos e pó doméstico em Portugal, e a avaliar os riscos associados a esta exposição. Os contaminantes estudados incluem: retardantes de chama bromados (BFRs); retardantes de chama fosforados (PFRs); bifenilos policlorados (PCBs); pesticidas organoclorados (OCs); e os metais tóxicos chumbo (Pb) e cádmio (Cd). Os níveis de BFRs, PCBs, OCs, Pb e Cd foram determinados em amostras de duplicados de dieta fornecidas por voluntários da comunidade académica da Universidade de Aveiro. No que diz respeito aos compostos orgânicos, as concentrações obtidas foram baixas. Os BFRs foram detetados em poucas amostras de dieta, sendo que o mais detetado foi o congénere BDE 209 (67%), enquanto os BFRs emergentes – 1,2-bis (2,4,6-tribromofenoxi) etano (BTBPE), decabromodifenill etano (DBDPE) – não foram detetados. Os PCBs e os OCs apresentaram as concentrações mais elevadas e foram detetados na maioria das amostras de duplicados de dieta analisadas, sendo que os diclorodifeniltricloroetanos (DDTs) e os hexaclorociclohexanos (HCHs) foram detetados em 100% das amostras. Os valores estimados das ingestões diárias foram baixos e abaixo dos valores de referência estabelecidos para a avaliação de risco em humanos. O Pb foi detetado em todas as amostras de duplicado de dieta e o seu consumo através da ingestão de alimentos foi associado a efeitos adversos para a saúde. Para 33% dos participantes a ingestão diária estimada (EDI) foi superior à dose de referência (bench mark dose level – BMDL) associada à doença renal crónica, e para um dos participantes a EDI foi 50% mais elevado do que a BMDL associada à pressão arterial sistólica elevada. A abordagem da margem de exposição (MOE - margin of exposure) foi aplicada e indicou que em pelo menos 3,3 e 26,7% dos participantes poderão surgir efeitos cardiovasculares e nefrotóxicos, respetivamente. As concentrações de Cd foram avaliadas em amostras de duplicados de dieta fornecidas por mulheres a trabalhar ou a estudar na Universidade de Aveiro. Este metal foi também detetado em todas as amostras analisadas e 35% das participantes apresentaram ingestões semanais estimadas (EWIs) mais elevadas do que a dose semanal tolerável estabelecida, sugerindo riscos de saúde elevados. No geral, os resultados obtidos através das análises feitas em amostra de duplicados de dieta demonstraram que a ingestão de alimentos é uma importante via de exposição aos contaminantes ambientais estudados. Os níveis de PFRs, BFRs and PCBs foram monitorizados em amostras de pó doméstico de casas de Aveiro e Coimbra. Estes compostos e os seus respetivos congéneres/isómeros foram detetados num grande número de amostras, sendo que os PFRs apresentaram as concentrações mais elevadas, seguidos dos BFRs e PCBs. Apesar das frequências de deteção elevadas, os EDIs foram inferiores às doses de referência (RfDs) estabelecidas. Os BFRs, PCBs, OCs foram também analisados em amostras de pó doméstico da Covilhã. Neste estudo, as amostras de pó foram recolhidas em casas de voluntários com asma e em casa de participantes sem asma. Os congéneres/isómeros dos contaminantes avaliados foram detetados na maioria das amostras, e o grupo de BFRs apresentou as concentrações mais altas, seguido de PCBs e DDTs. No entanto, para todos os contaminantes, as ingestões diárias foram inferiores às RfDs. Estes resultados confirmam que os PFRs, BFRs, PCBs e OCs estão omnipresentes nas casas Portuguesas, no entanto, o consumo diário dos contaminantes orgânicos através da ingestão de pó doméstico é baixo. Os resultados obtidos no âmbito desta tese permitiram descrever, pela primeira vez em Portugal, os níveis dos contaminantes selecionados em amostras de duplicados de dieta e pó doméstico. Estes resultados revelaram que o risco associado à ingestão de contaminantes orgânicos através da alimentação e do pó doméstico foram baixos, ao contrário do elevado risco associado à ingestão de Pb e Cd presentes nos alimentos.
Humans are permanently exposed to environmental contaminants which have been produced for decades and with numerous applications. Besides the direct contact with the consumer products in which these contaminants are applied, the exposure occurs mainly because these chemicals are released from those materials and accumulate in the environment being available for involuntary consumption. For a long time, diet has been considered the major human exposure route for several contaminants, including persistent organic pollutants (POPs) and toxic metals. However, the indoor exposure through dust emerged as important exposure route, mainly motivated by the fact that these contaminants accumulate in dust and because people in modern society spend much of their time indoors. In this thesis, several classes of environmental contaminants were analysed in duplicate diet samples and house dust in order to characterize the human exposure through the ingestion of food and the ingestion of house dust in Portugal and to access the associated risks. The contaminants studied include: brominated flame retardants (BFRs), phosphorus flame retardants (PFRs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCs), and also the toxic metals lead (Pb) and cadmium (Cd). The levels of BFRs, PCBs, OCs, Pb and Cd were assessed in duplicate diet samples obtained from volunteers from the University of Aveiro community. Regarding the organic compounds the obtained levels were low. BFRs were detected in few duplicate diet samples, with the congener BDE 209 exhibiting the higher detection frequency (67%) while the emerging BFRs – 1,2-bis (2,4,6-tribromophenoxy) ethane (BTBPE), decabromodiphenyl ethane (DBDPE) – were not detected. PCBs and OCs exhibited higher levels and were detected in most analysed duplicate diet samples, with dichlorodiphenyltrichloroethanes (DDTs) and hexachlorocyclohexanes (HCHs) being detected in 100% of the samples. The daily dietary intakes were estimated, being low and under the established guidance values for human risk assessment. Pb was detected in all duplicate diet samples and its dietary ingestion was associated with adverse health effects. For 33% of the participants, the estimated daily intakes (EDIs) were higher than the dietary intakes related to the bench mark dose level (BMDL) derived from chronic kidney disease, and for one participant the EDI was 50% higher than the BMDL derived from elevated systolic blood pressure. The margin of exposure approach (MOE) was applied and indicated that cardiovascular and nephrotoxic effects might likely occur in at least 3.3 and 26.7% of the participants, respectively. The concentrations of Cd were assessed in duplicate diet samples provided by women working or studying in University of Aveiro. This metal was also detected in all analysed samples and 35% of the participants exhibited estimated weekly intakes (EWIs) higher than the established tolerable weekly intake (TWI), suggesting increased health risks. Overall the results from the duplicate diet study demonstrate that the ingestion of food is an important pathway of exposure to these environmental contaminants. PFRs, BFRs and PCBs were monitored in house dust samples from two cities in central Portugal (Aveiro and Coimbra). These compounds and respective congeners/isomers were detected in a large number of samples, with PFRs exhibiting the highest concentrations followed by BFRs and PCBs. Despite their high detection frequencies, the EDIs were much lower than the established reference doses (RfDs). BFRs, PCBs and OCs were also analysed in house dust samples from Covilhã, Portugal. In this study, dust samples were collected from the houses of asthmatics and non-asthmatics participants. The contaminants congeners/isomers were detected in the majority of the dust samples, and the group of BFRs exhibited the higher concentrations, followed by PCBs and DDTs, however, the daily intakes were lower than the RfDs for all contaminants. These results confirm that PFRs, BFRs, PCBs and OCs are ubiquitously present in Portuguese households, however the daily intakes of these organic contaminants through house dust ingestion is low. The results obtained under the framework of this thesis allowed describing for the first time in Portugal the levels of the selected contaminants in duplicate diet samples and in house dust samples. The results disclosed that the risk associated with the ingestion of the organic contaminants through diet and house dust was low, which contrasts with the risk associated with the ingestion of Pb and Cd through diet.
McGinley, Susan. "Evaluating Contaminants in Colorado River Water." College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2010. http://hdl.handle.net/10150/622078.
Full textAttanayake, Chammi. "Bioavailability of contaminants in urban soils." Diss., Kansas State University, 2014. http://hdl.handle.net/2097/17601.
Full textDepartment of Agronomy
Ganga M. Hettiarachchi
Urban soils may contain harmful levels of potentially toxic contaminants. These contaminants transfer to humans via two exposure pathways: direct transfer (soil-humans by soil ingestion, dermal exposure and inhalation) and food chain transfer (soil-plant-humans). Soil amendments alter the speciation of the contaminants in soils and thereby modify their bioavailability. The objectives of this research were to access the plant availability of lead (Pb), arsenic (As), and polycyclic aromatic hydrocarbons (PAHs); bioaccessibility and speciation of soil Pb, and As; and dermal absorption of soil PAHs in contaminated urban soils; and effectiveness of soil organic amendments on reducing contaminant bioavailability. Two field experiments were conducted in Kansas City, MO and Indianapolis, IN. Both sites had elevated concentrations of Pb in soils (Kansas City site: 30-380 mg kg⁻¹ and Indianapolis site: 200-700 mg kg⁻¹) . Indianapolis site’s soils also had elevated concentrations of As (40-100 mg kg⁻¹) and PAHs (benzo[a]pyrene: 1-10 mg kg⁻¹) . A control treatment (no-compost) and compost-types (leaf compost and/or composted biosolids, non-composted biosolids, mushroom compost) were used as treatments. A leafy vegetable, a fruiting vegetable and a root crop were grown for two growing seasons. The treatments were arranged in split-plot design (main plot factor: compost; sub-plot factor plant-type). An in vitro steady fluid experiment was conducted using human skins to examine the dermal transfer of soil PAHs. The concentrations of Pb, As, and PAHs in the vegetables were low, except Pb in root crops. Compost reduced the bioaccessibility of Pb, but did not change the bioaccessibility of As. Selected soil samples were analyzed for speciation of Pb using extended x-ray absorption fine structure spectroscopy. The predominant Pb species were Pb sorbed to Fe oxy(hydr)oxide and to organic C. Stable Pb phosphates (pyromorphite) was formed during the in vitro extraction. Dermal transfer experiments showed PAHs in the contaminated soils did not transfer through the skin. Stratum conium of the skin acted as a barrier for dermal transfer of soil PAHs. In general, the risk of food chain transfer of soil Pb, As, and PAHs were low in the studied sites and can be further reduced by compost addition. Bioaccessibility of Pb and As in urban soils were low. Dermal absorption of soil PAHs was insignificant.
Onogbosele, Cyril Oziegbe. "Bioavailability of organic contaminants in rivers." Thesis, Brunel University, 2015. http://bura.brunel.ac.uk/handle/2438/11050.
Full textAndaluri, Gangadhar. "Ultrasound induced destruction of emerging contaminants." Diss., Temple University Libraries, 2011. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/111771.
Full textPh.D.
There are many reports indicating the presence of emerging contaminants such as: estrogen hormones, 1,4-dioxane and perfluoro-octanoic acids in the natural environment. Estrogen hormones are considered important emerging class of contaminants due to their endocrine disrupting effects. These compounds are invariably found in the environment originating mostly from natural sources. Trace concentrations of estrogen hormones (low µg/L concentrations) have been detected in municipal wastewater treatment plants and observed in receiving water bodies. 1,4-Dioxane (C4H8O2) is used as an organic solvent and solvent stabilizer numerous in chemical processes. The United States Environmental Protection Agency (US-EPA) has recognized 1,4-dioxane as a toxic chemical and a possible human carcinogen. 1,4-dioxane has been detected as a contaminant in the natural environment, drinking water supplies, superfund sites, public groundwater sources in the United States, Canada and Japan at concentrations greater than the permissible standards. Perfluorinated chemicals such as perfluoro-octanoic acid (PFOA) and perfluorooctane-sulfonate (PFOS) have been manufactured for use in a variety of industrial and consumer applications. Due to their environmental persistence, PFOAs have been detected in surface waters at a number of locations at concentrations ranging from pg/L to ng/L. Elevated concentrations of PFOAs have been measured in surface and ground waters near specific point sources. Through this project, successful attempts have been made for the destruction of emerging contaminants using ultrasound. This study deals with the optimization of various process parameters for the destruction of estrogen hormones. The influence of process parameters such as power density, reactor geometry, power intensity, ultrasound amplitude, and external mixing was investigated. Artificial neural network (ANN) approach was used to describe the interactions between optimized parameters. The important findings obtained in the present work for the optimized estrogen degradation can help tackle the challenges of scale up such as operational optimization and energy consumption. The effect of process conditions such as pH and presence of oxidizing agents on the ultrasonic destruction of 1,4-dioxane and PFOA was studied. Acidic conditions favored the destruction of both the compounds. The presence of activated sulfate radicals enhanced the reaction rate kinetics. An innovative technology using electric potential and ultrasound for the removal organic contaminants was developed. The existence of organic contaminants in ionic form under certain process conditions has led to the development of this technology. Applying a low electric potential across the probe enhances the mass transfer of the contaminants into effective reaction zone, thereby enhancing the total destruction. A two-fold increase in the reaction rates was observed. This study shows ultrasound as an efficient and effective treatment technology for the destruction of emerging contaminants.
Temple University--Theses
Ridgway, Kathy. "Determination of trace contaminants in foods." Thesis, Loughborough University, 2008. https://dspace.lboro.ac.uk/2134/20861.
Full textRibeiro, Alyson Rogério 1986. "Potencial do uso de planárias na avaliação de contaminantes ambientais=Potential use of planarians for environmental contaminants evaluation." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/267776.
Full textDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Tecnologia
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Resumo: As planarias de água doce possuem vasta distribuição geográfica, plasticidade biologica, facilidade de cultivo em laboratório, sensibilidade a contaminantes diversos e capacidade regenerativa, por isso vem sendo utilizadas como organismos-teste em ensaios ecotoxicologicos. Porem, ainda não ha normatização internacional ou nacional que padronize esses ensaios. O objetivo deste trabalho foi verificar o potencial do uso de planarias de agua doce (Girardia tigrina) na avaliação de alguns contaminantes e amostras ambientais utilizando protocolos padronizados avaliando-se mortalidade e atraso na regeneração encefálica. Foram empregados 15 organismos por concentração-teste nos ensaios de mortalidade de filhotes (96h) e 20 planarias adultas regenerantes por concentração-teste nos ensaios de regeneração encefálica (120h). Avaliou-se cromo e zinco como substancias de referencia e empregou-se cobre, azo corante têxtil Disperse Red 1, herbicida atrazina, nanotubos de carbono de parede múltipla, alem de amostras da ETE Carioba e do Ribeirão dos Cristais. Carta controle com substancia de referencia foi realizada, sendo estabelecido um protocolo para o monitoramento da sensibilidade das culturas de G. trigrina. O zinco foi a substancia mais apropriada que o cromo, com a vantagem do ensaio de sensibilidade poder ser finalizado em 24h. Os métodos utilizados para realização do ensaio de regeneração encefálica e de mortalidade de filhotes foram eficazes para a observação de efeitos adversos das substancias analisadas. Todas as amostras testadas apresentaram toxicidade as planarias, exceto os nanotubos de carbono. Atraso na regeneração encefálica foi o endpoint mais sensível para os contaminantes avaliados. Os protocolos utilizados neste estudo podem ser utilizados como subsídios na elaboração futura de normas técnicas de testes ecotoxicologicos com planarias de agua doce
Abstract: Freshwater planarians are worldwide distributed, have biological plasticity and a unique body regenerative capacity. They are easily maintained under laboratorial conditions and are sensitive for several compounds. For these reasons they have been used in ecotoxicological testing although the lack of national or international guidelines. This research aimed to verify the potential use of freshwater planarians (Girardia tigrina) in mortality and regeneration delay endpoints to assess the toxicity of environmental contaminants using standardized protocols. The culture sensitivity of G. tigrina was monitored with zinc, which was the most suitable substance for this purpose, providing responses in only 24h. The adopted protocols for regeneration and mortality tests were efficient to assess the adverse effects of the chemical agents (copper, an azo textile dye, atrazine), carbon nanotubes and wastewater and water samples from Carioba WWTP and Cristais River. The regeneration test was the most sensitive endpoint and all analyzed substances showed toxicity for planarians, except carbon nanotubes. The methods adopted in this research can be used as basis for the development of a testing guideline using freshwater planarians
Mestrado
Tecnologia e Inovação
Mestre em Tecnologia
Vesely, William C. "Emerging Contaminants: Occurrence of ECs in Two Virginia Counties Private Well Water Supplies and Their Removal from Secondary Wastewater Effluent." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/83829.
Full textMaster of Science
Strid, Anna. "Organohalogen contaminants in Greenland shark (Somniosus microcephalus)." Doctoral thesis, Stockholms universitet, Institutionen för material- och miljökemi (MMK), 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-45828.
Full textAt the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.
Ramírez, González Noelia. "Organic contaminants in environmental atmospheres and waters." Doctoral thesis, Universitat Rovira i Virgili, 2011. http://hdl.handle.net/10803/38880.
Full textThis Doctoral Thesis focuses on the development of efficient and highly sensitive analytical methods for determining organic contaminants in atmospheric, aquatic and house dust samples. The proposed analytical methods are based on single and comprehensive gas chromatography followed by different detectors (including mass spectrometry and nitrogen chemiluminiscence detection) and different sample preparation methods that have the aim of minimising the consumption of organic solvents in the whole analytical process. The organic contaminants selected in this Thesis include several families of volatile organic compounds, polycyclic aromatic hydrocarbons and some emerging contaminants, such as personal care products, nicotine and N-nitrosamines. This Thesis also characterises the air and water quality of the Tarragona area through the analysis of several environmental samples and estimates the risk by inhalation of organic contaminants in people living around the largest chemical site of the Mediterranean.
Tolar, Stephen Douglas. "Adsorption of Water Contaminants Onto Kenaf Fibers." MSSTATE, 2006. http://sun.library.msstate.edu/ETD-db/theses/available/etd-07132006-135916/.
Full textHeim, Sabine. "Geochronology of anthropogenic contaminants in fluvial sediments /." Aachen : Shaker, 2005. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=014779100&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.
Full textWang, Jiankang. "Understanding electrochemical inactivation of contaminants in water." Diss., The University of Arizona, 2004. http://etd.library.arizona.edu/etd/GetFileServlet?file=file:///data1/pdf/etd/azu_e9791_2004_163_sip1_w.pdf&type=application/pdf.
Full textKerns, David L. "Common Insect Contaminants Found in Arizona Lettuce." College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2000. http://hdl.handle.net/10150/144795.
Full textThis publication describes the common insects found in Arizona lettuce through the use of pictures. The insects include; lepidopterous larva, striped flea beetle, leafminer fly, leafminer mine, adult western flower thrips, winged adult aphid, false chinch bug, lygus bug, potato leafhopper, and threecornered alfalfa hopper.
Taylor, Jackie V. "Migration of contaminants associated with pavement construction." Thesis, University of Nottingham, 2004. http://eprints.nottingham.ac.uk/11908/.
Full textChen, Hung-Yu. "Azaarenes as contaminants of the urban atmosphere." Thesis, University of Liverpool, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320497.
Full textShapiro, Andrew P. "Electroosmotic purging of contaminants from saturated soils." Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/13674.
Full textBrooker, Michael R. "Water Contaminants of the Lake Erie Watershed." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1513950758388254.
Full textPatterson, Andrea. "Sorption of Anionic Organic Contaminants to Goethite." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1543427642730863.
Full textJiang, Yanan. "Emerging contaminants : environmental fate of artifical sweeteners." HKBU Institutional Repository, 2013. http://repository.hkbu.edu.hk/etd_ra/1508.
Full textGoh, Sher Leen. "Removal of organic contaminants from aqueous systems." Thesis, University of Strathclyde, 2015. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=24743.
Full textDempster, Helen Stephanie. "Isotopic applications to contaminant hydrogeology, using [delta]¹³C analysis to investigate the origin and fate of dissolved organic contaminants." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq29251.pdf.
Full textSitzlar, Megan Annette. "P450 aromatase alterations and DNA damage as avian pollution biomarkers in cliff and cave swallow breeding near the Rio Grande region, Texas." Texas A&M University, 2005. http://hdl.handle.net/1969.1/3223.
Full textSantos, Maria Carla Barreto. "Avaliação da contaminação por metais em solos impactados pela disposição de rejeitos industriais: estudo de caso – CENTRES (Queimados, RJ)." Niterói, 2017. https://app.uff.br/riuff/handle/1/4595.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Universidade Federal Fluminense. Instituto de Química. Programa de Pós-Graduação em Geoquímica, Niterói, RJ
O Centro Tecnológico de Resíduos (CENTRES) é um exemplo de passivo ambiental localizado no município de Queimados, RJ. Neste local, toneladas de resíduos industriais foram armazenadas sem nenhum critério ou fiscalização. Os recipientes contendo rejeitos químicos sofreram vazamentos e ocasionaram o contato de metais tóxicos com o solo. Metais tóxicos no solo associam-se a diversos componentes orgânicos e inorgânicos, apresentando-se em diversas formas químicas que podem interferir na mobilidade destes metais no solo Este estudo visa observar a presença e a mobilidade dos metais Cádmio, Cromo, Cobre, Níquel, Chumbo e Zinco no solo do CENTRES. Para tal foram realizadas análises de caracterização do solo e extrações pseudototais e sequenciais em amostras de sete diferentes pontos da localidade mencionada. As análises físicas do solo foram realizadas segundo a metodologia da EMBRAPA (1997). As análises químicas para avaliação da concentração dos metais no solo e para fracionamento geoquímico foram realizadas com os métodos US EPA3051 e BCR, respectivamente. No método BCR as frações solúveis em ácido, redutível e oxidável, e residual são obtidas através de ataques químicos sucessivos. As análises de caracterização física mostraram um solo predominantemente franco-argiloarenoso, com pH variando entre 4,2 e 6,9 e baixa capacidade de troca de cátions. As análises de concentração de contaminantes mostraram solos com valores acima da recomendação sugerida pela Companhia de Tecnologia de Saneamento Ambiental (CETESB, 2005) e pela Resolução CONAMA (2009), com destaque para os pontos P5 e P6, que apresentaram altas concentrações de contaminantes. Dos sete pontos analisados, quatro estavam classificados como solos Classe 3 ou Classe 4 de acordo com CONAMA (2009), o que demonstra a gravidade da contaminação da área. O Fracionamento Geoquímico das amostras mostrou que em P1, P2, P5 e P6 os metais que apresentam maiores concentrações, encontram-se também na Fração Trocável do solo, ou seja, a Fração mais disponível ao ambiente. Em contrapartida, Zinco e Chumbo apresentaram altas concentrações na Fase Residual do solo.
Centro de Tecnológico de Resíduos (CENTRES) is an example of environmental liabilities in the town of Queimados, RJ. In this place, tons of industrial waste were stored without any discretion or supervision. The containers of chemical waste have suffered and caused leaks of toxic metals contact with the ground. Toxic metals in soil are associated with various organic and inorganic components, performing in various chemical forms that can interfere with the mobility of these metals in the soil. This study aims to observe the presence and mobility of metals Cadmium, Chromium, Copper, Nickel, Lead and zinc in soil from the center. For this analysis were performed to characterize the soil and pseudototais extractions and sequential samples from seven different points in the locality mentioned. The physical analysis of soil were performed using the methodology of EMBRAPA (1997). The chemical analysis to assess the concentration of metals in soil and geochemical fractionation methods were performed with the US EPA3051 and BCR, respectively. In BCR fractions soluble in acid, reducible and oxidizable, and residual are obtained by successive chemical attacks. The analysis of physical characterization showed a sandy-clay loam, with pH ranging between 4.2 and 6.9 and low cation exchange capacity. The analysis showed the concentration of contaminants in soil above the recommended values suggested by the Companhia de Tecnologia de Saneamento Ambiental (CETESB, 2005) and by CONAMA (2009), highlighting the points P5 and P6, which showed high concentrations of contaminants in area. Of the seven points analyzed, four were classified as Class 3 soils or Class 4 according to CONAMA (2009). The Geochemical fractionation of samples showed that in P1, P2, P5 and P6, the metals that have higher concentrations are also found in the exchangeable fraction of soil, the fraction most available to the environment. In contrast, zinc and lead concentrations were high in Residual Phase soil.