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Artykuły w czasopismach na temat "And contaminants"
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Olson, Nathan D., Justin M. Zook, Jayne B. Morrow i Nancy J. Lin. "Challenging a bioinformatic tool’s ability to detect microbial contaminants usingin silicowhole genome sequencing data". PeerJ 5 (12.09.2017): e3729. http://dx.doi.org/10.7717/peerj.3729.
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High sensitivity methods such as next generation sequencing and polymerase chain reaction (PCR) are adversely impacted by organismal and DNA contaminants. Current methods for detecting contaminants in microbial materials (genomic DNA and cultures) are not sensitive enough and require either a known or culturable contaminant. Whole genome sequencing (WGS) is a promising approach for detecting contaminants due to its sensitivity and lack of need fora prioriassumptions about the contaminant. Prior to applying WGS, we must first understand its limitations for detecting contaminants and potential for false positives. Herein we demonstrate and characterize a WGS-based approach to detect organismal contaminants using an existing metagenomic taxonomic classification algorithm. Simulated WGS datasets from ten genera as individuals and binary mixtures of eight organisms at varying ratios were analyzed to evaluate the role of contaminant concentration and taxonomy on detection. For the individual genomes the false positive contaminants reported depended on the genus, withStaphylococcus,Escherichia, andShigellahaving the highest proportion of false positives. For nearly all binary mixtures the contaminant was detected in thein-silicodatasets at the equivalent of 1 in 1,000 cells, thoughF. tularensiswas not detected in any of the simulated contaminant mixtures andY. pestiswas only detected at the equivalent of one in 10 cells. Once a WGS method for detecting contaminants is characterized, it can be applied to evaluate microbial material purity, in efforts to ensure that contaminants are characterized in microbial materials used to validate pathogen detection assays, generate genome assemblies for database submission, and benchmark sequencing methods.
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Rouel, Melissa, Richard J. Stevenson i Evelyn Smith. "Examination of Responses Involved in Contamination Aversion Based on Threat Type". Journal of Social and Clinical Psychology 37, nr 2 (luty 2018): 83–106. http://dx.doi.org/10.1521/jscp.2018.37.2.83.
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There is evidence that different types of contaminants produce different responses and have different motivations for avoidance. Contaminants directly associated with disease (direct contaminants) are motivated by disgust avoidance, whereas contaminants indirectly associated with disease (indirect contaminants) and contaminants associated with harmful substances (harm contaminants) are motivated by harm avoidance and threat estimations. This study aims to confirm this distinction between contaminant types and examine the role of cognitive load, awareness and time on processing these threats. One hundred and four participants completed three chain of contagion tasks with direct, indirect, and harm contaminants. Cognitive load, awareness of contamination and time were manipulated during the tasks. Consistent with previous findings, direct contaminants produced stronger disgust responses, while harm and indirect contaminants produced stronger threat estimations. Increasing cognitive load did not impact processing of any type of contaminant. There was evidence that a time delay reduced the spread of contagion for all contaminants. This highlights the importance of time in altering the perception of contamination threat. Implications and future research directions are discussed.
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Gewurtz, Sarah B., i Miriam L. Diamond. "Distribution and burdens of bioaccumulative contaminants in the Lake Erie food web: A review". Environmental Reviews 11, nr 3 (1.09.2003): 141–60. http://dx.doi.org/10.1139/a03-014.
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The bioaccumulation of organic contaminants in the Lake Erie food web is reviewed in context of the numerous changes experienced by the system. In the late 1960s, internal lake processes, related to the eutrophic status of the lake, minimized contaminant bioaccumulation despite high contaminant loadings. From the 1970s to 1980s contaminant concentrations decreased at different rates in many species of different trophic levels, coincident with decreased loadings to the lake. Since the early 1980s contaminant concentrations in biota have not changed consistently. Several factors have been proposed to account for these patterns, including reduced nutrient loadings and productivity, and the invasion of several exotic species such as zebra mussels. These factors have altered the food web structure and the internal distribution of contaminants in the lake. Emerging and continuing issues, such as climate change, invasions of additional exotic species, new chemical contaminants of concern, and algal toxins will likely impact contaminant dynamics in the future.Key words: Lake Erie, bioaccumulative contaminants, food web.
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Montagna, Paul A., Stephen C. Jarvis i Mahlon C. Kennicutt, II. "Distinguishing between contaminant and reef effects on meiofauna near offshore hydrocarbon platforms in the Gulf of Mexico". Canadian Journal of Fisheries and Aquatic Sciences 59, nr 10 (1.10.2002): 1584–92. http://dx.doi.org/10.1139/f02-131.
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Offshore hydrocarbon production effects are localized in the Gulf of Mexico extending only 200 m from platforms. Effects are caused by the contaminant gradient or the fouling community on platform legs. To distinguish between contaminant and reef effects, meiofauna were sampled at production platforms (reef and contaminant effects), artificial reefs (reef, but no contaminant effects), platform removal sites (contaminant, but no reef effects), and controls (no contaminants or reef effects), and replicated in three blocks. The removal sites had higher concentrations of many contaminants than reef or control sites, but lower concentrations than platform sites. Reduced meiobenthic abundances and altered Harpacticoida community structure were primarily a function of reef effects, not contaminant effects. The habitat influence is likely a result of complex ecological interactions near platforms. The reef effect appears to be important in controlling meiofauna near platforms where contaminants are low because of drilling and production techniques used in the Gulf of Mexico. The finding that contaminants alone do not explain faunal patterns around offshore platforms indicates that future studies should include appropriate artificial reef control sites.
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MacDonald, Kristi, i Mara Tippett. "Reducing public exposure to common, harmful well water contaminants through targeted outreach to highly susceptible neighborhoods as a method of increasing the likelihood of testing and treatment of water from private wells". Journal of Water and Health 18, nr 4 (8.07.2020): 522–32. http://dx.doi.org/10.2166/wh.2020.059.
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Abstract While the Safe Drinking Water Act mandates testing of public water supplies in the USA, private well owners are responsible for testing and treating their own water. A small percentage of well owners perform annual testing as recommended and many never test at all for common and potentially harmful groundwater contaminants. Finding effective ways to inform residents of the risks associated with their private well drinking water and promote the testing and treatment for common contaminants is a challenge faced by federal, state, and local agencies concerned with public health. Targeting residents whose wells are most at risk for having levels of regulated contaminants above the drinking water standard is a potential way to efficiently reach individuals. Results of this study show that individuals who receive specific letters that a contaminant in a neighbor's well had exceeded the maximum contaminant levels for one of five common well water contaminants (arsenic, radon, Gross Alpha, Escherichia coli, and nitrates) were more likely to test their well than were individuals who received a general letter about common contaminants in the region. Outreach that reports more localized, specific information on contaminants in well water results in an increased chance of testing when compared with more regional and generalized contaminant information.
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Liu, Shuming, Han Che, Kate Smith i Tian Chang. "Contaminant classification using cosine distances based on multiple conventional sensors". Environmental Science: Processes & Impacts 17, nr 2 (2015): 343–50. http://dx.doi.org/10.1039/c4em00580e.
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This paper proposes a new contaminant classification method to discriminate contaminants in a real time manner, independent of the contaminant concentration. The proposed method quantifies the similarities or dissimilarities between sensors' responses to different types of contaminants. The performance of the proposed method was evaluated using data from injection experiments and compared with a Euclidean distance-based method.
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Callen, Cheryl, Jatinder Bhatia, Laura Czerkies, William Klish i George Gray. "Challenges and Considerations When Balancing the Risks of Contaminants with the Benefits of Fruits and Vegetables for Infants and Toddlers". Nutrients 10, nr 11 (24.10.2018): 1572. http://dx.doi.org/10.3390/nu10111572.
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Background: Fruits and vegetables are key to a healthy diet, particularly in children; however, parents may be concerned about contaminants found in fruits and vegetables. Making informed food choices for children requires understanding and balancing the risks of contaminant exposure with the importance of providing a healthy diet. The objective of this work is to identify fruits and vegetables commonly consumed by infants and toddlers; identify potential contaminants in fruits and vegetables; and outline considerations in assessing contaminant risks in food categories with a critical role in a healthy diet. Method: Commonly consumed fruits and vegetables were obtained from the Feeding Infants & Toddlers Study (FITS 2016). The US Food and Drug Administration Total Diet Study was reviewed for contaminant occurrence, and multiple experts were consulted on considerations in assessing risk of certain contaminants. Results: FITS data show eight fruits and nine vegetables account for over 80% of consumption in infants and toddlers. Several contaminants have been detected in fruits and vegetables. Questions to be addressed prior to establishing contaminant guidance were identified. Conclusion: Contaminant guidance for fruits and vegetables consumed by infants and toddlers raises several challenges. Expertise from multiple disciplines is required to find an approach that maximizes public health benefit.
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Kaag, N. H. B. M., E. M. Foekema i M. C. Th Scholten. "Ecotoxicity of contaminated sediments, a matter of bioavailability". Water Science and Technology 37, nr 6-7 (1.03.1998): 225–31. http://dx.doi.org/10.2166/wst.1998.0756.
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Marine and freshwater mesocosm-scale experiments with contaminated sediments have shown that there is a direct relationship between the accumulated contaminant levels and the feeding habits of the organisms used. The highest levels of PAHs and PCBs were found in the sediment feeding lugworm Arenicola marina and in Tubifex worms. The levels of contaminants in the suspension feeding mussels Mytilus edulis and the zebra mussels, Dreissena polymorpha, were not influenced by the contaminant content of the sediments, but were related instead to the level of contaminants in the sea water above. Intermediate levels were found in the baltic tellin, Macoma balthica, which is a filter feeder as well as a deposit feeder, depending on the availability of food. These results show that there is no simple relationship between contaminant concentration in the sediments and bioavailability. Higher levels of contaminants do not necessarily lead to higher levels of these contaminants in Arenicola, due to differences in the sediment structure and the ageing of the contamination. On the other hand, toxic effects are related to the internal concentrations of certain chemicals. The internal concentrations observed in Arenicola may provide a good estimation of the true bioavailability of sedimentary contaminants and can also be used as an indicator for potential environmental effects.
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Chappell-Campbell, Laura, Hayden T. Schwenk, Nicole Capdarest-Arest i Alan R. Schroeder. "Reporting and Categorization of Blood Culture Contaminants in Infants and Young Children: A Scoping Review". Journal of the Pediatric Infectious Diseases Society 9, nr 2 (13.12.2018): 110–17. http://dx.doi.org/10.1093/jpids/piy125.
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Abstract Background Blood cultures are obtained routinely for infants and young children for the evaluation for serious bacterial infection. Isolation of organisms that represent possible contaminants poses a management challenge. The prevalence of bacteremia reported in this population is potentially biased by inconsistent contaminant categorization reported in the literature. Our aim was to systematically review the definition and reporting of contaminants within the literature regarding infant bacteremia. Methods A search of studies published between 1986 and mid-September 2016 was conducted using Medline/PubMed. Included studies examined children aged 0 to 36 months for whom blood culture was performed as part of a serious bacterial infection evaluation. Studies that involved children in an intensive care unit, prematurely born children, and immunocompromised children or those with an indwelling catheter/device were excluded. Data extracted included contaminant designation methodology, organisms classified as contaminants and pathogens, and contamination and bacteremia rates. Discussion Our search yielded 1335 articles, and 69 of them met our inclusion criteria. The methodology used to define contaminants was described in 37 (54%) study reports, and 16 (23%) reported contamination rates, which ranged from 0.5% to 22.8%. Studies defined contaminants according to organism species (n = 22), according to the patient’s clinical management (n = 4), and using multifactorial approaches (n = 11). Many common organisms, particularly Gram-positive cocci, were inconsistently categorized as pathogens or contaminants. Conclusions Reporting and categorization of blood culture contamination are inconsistent within the pediatric bacteremia literature, which limits our ability to estimate the prevalence of bacteremia. Although contaminants are characterized most frequently according to organism, we found inconsistency regarding the classification of certain common organisms. A standardized approach to contaminant reporting is needed.
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Wang, Rong Guang, Mitsuo Kido, Suketsuku Nakanishi i Takuji Okabe. "Observation and Removal of Atmospheric Micro-Contaminants on SUS304 Steel". Advanced Materials Research 189-193 (luty 2011): 876–80. http://dx.doi.org/10.4028/www.scientific.net/amr.189-193.876.
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Micro-contaminants on SUS304 stainless steel were observed and confirmed by atomic force microscope, and the micro-contaminant removal was carried out by ultraviolet (UV) illumination. The amount of micro-contaminants on the specimen surface decreased with an increase in the UV illumination time, with extensive removal of the organic substance in the contaminants but leaving part of the contained water in the contaminants. The surface for macro-droplets after the UV illumination became hydrophilic, while no large change of the wettability for micro-droplets on the same surface can be observed.
Rozprawy doktorskie na temat "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.
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La detección de contaminantes peligrosos requiere especial atención debido a su posible toxicidad, baja concentración en muestras reales y, en la mayoría de los casos, una imposibilidad de llevar a cabo la detección a través de un metodo tan específico como el inmunoensayo. Una de las estrategias orientadas a la fácil detección de compuestos nocivos es el uso de plataformas microfluídicas llamadas Lab-on-a-chip.
En el Capítulo 3, una innovadora plataforma microfluídica en miniatura es desarrollada para la detección simultánea y extracción de polibromodifenil éteres (PBDEs). La plataforma consiste en un chip microfluídico de polidimetilosiloxano (PDMS) para el paso de la inmunoreacción, un chip de PDMS con un electrodo serigrafiado de carbono (SPCE) integrado para la detección, y un chip de PDMS-óxido de grafeno reducido (rGO) para la adsorción física y posterior eliminación de residuos de PBDE. La detección se basó en un inmunoensayo competitivo entre PBDE y PBDE modificado con Peroxidasa de Rábano Silvestre (HRP-PBDE) seguido de un monitoreo de oxidación enzimática de o-aminofenol (o-AP), utilizando voltamperometría de onda cuadrada y resolución anódica (SW-ASV). PBDE fue detectado con una buena sensibilidad y un límite de detección similar al obtenido a través de una prueba colorimétrica comercial (0.018 ppb), pero con la ventaja de utilizar volúmenes reactivos más bajos y un tiempo de análisis reducido. Con el objetivo de diseñar un sistema de detección apropiado para compuestos tóxicos como PBDEs, un compósito de óxido de grafeno reducido y PDMS ha sido desarrollado y optimizado para obtener mayor adsorción (basados en hidropobicidad e interacción π–π entre moléculas de rGO y PBDE) comparado con los PDMS sin modificación. Este sistema se puede aplicar perfectamente para detectar cualquier análito utilizando el inmunoensayo apropiado y facilitar el funcionamiento en matrices tan complejas como el agua marina.
En el Capítulo 4 se desarrolla un dispositivo LOC para la preconcentración y la detección simultánea de metales pesados. Dicho dispositivo consta de un electrodo serigrafiado de carbono, un chip de PDMS y otro de GO-PDMS. El chip de GO-PDMS fue fabricado y los factores más esenciales fueron optimizados, incluidos la concentración de GO y aquella del curador de PDMS. Se descubrió que la habilidad de adsorción es inversamente proporcional a la concentración de curador de PDMS en el compósito y proporcional a la concentración de GO. El mecanismo de adsorción está basado en una reacción de complejación , donde grupos activos de oxígeno con cargas negativas se pueden enlazar con metales bivalentes como el Pb. La adsorción más alta fue obtenida en pH=7.
El GO-PDMS tiene una capacidad relativamente grande de adsorción, ya que incluso las muestras que contienen niveles más altas que 500 ppb (mayores a 500 ppb) son totalmente adsorbidas, teniendo en cuenta que tal concentración es muy alta.
El proceso de desorción ha sido también optimizado. Gracias a ello, metales que habían sido previamente adsorbidos se pueden liberar y detectar en voltamperometría de Onda Cuadrada y Resolución Anódica. El límite de detección de esta técnica (utilizando electrodos serigrafiados de carbono) fue de 0.5 ppb para el plomo (Pb). Esto significa que utilizando una plataforma de preconcentración GO-PDMS, se pueden cuantificar cantidades más bajas de Pb, ya que las muestras preconcentradas mostraron una corriente de hasta 30 veces más alta que las no preconcentradas.
Esta plataforma se puede utilizar para la detección mejorada de metales pesados y también para su eliminación.The 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.
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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.
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Els contaminants orgànics són substàncies químiques amb el potencial de causar efectes adversos al medi ambient i/o a la salut humana. Degut a l’ús cada cop més elevat de substàncies químiques i la seva emissió continuada al medi ambient, aquestes es poden considerar com a pseudo-persistents, convertint en una prioritat el monitoratge de la seva presència al medi ambient. Un dels aspectes que està suscitant una major preocupació es el control dels contaminants orgànics al medi aquàtic, ja que pot afectar de manera significativa a la seva qualitat.
En aquest sentit, l'objectiu principal d'aquesta Tesi es el desenvolupament de metodologia analítica basada en la cromatografía líquida acoblada a l'espectrometría de masses en tandem, utilitzant un analitzador de triple quadrupol, per a la determinació de certs contaminants orgànics, tant prioritàris com emergents, en mostres d'aigua.
Un cop la metodologia ha estat desenvolupada i validada, ha estat aplicada a l'analisi de mostres d'aigua del riu Ebre i a mostres recollides en una ETAP. D'aquesta manera s'ha pogut avaluar la presència d'aquests contaminants en aquestes aigües, així com l'efectivitat dels diferents tractaments aplicats en aquesta ETAP per a l'eliminació d'aquests contaminants.Los 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.
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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.
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Fujii, 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/.
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Objetivo. Comparar a qualidade do ar externo com o ambiente interno das estações Clínicas e Praça da Sé do Metrô de São Paulo, quantificando e qualificando os contaminantes microbiológicos e atmosféricos. Propõe-se com este estudo promover o conhecimento de fatores sobre a qualidade do ar e das condições de higiene e saúde destes locais, contribuindo para a melhoria da qualidade de vida dos trabalhadores e usuários do sistema. Métodos. As amostras foram realizadas no período de Julho a Novembro de 2005. Os fungos foram coletados com o impactador de Andersen de um estágio com volume de aspiração de 28 l/min por um tempo de 10 minutos por amostra, e como meio de cultivo Agar Sabouraud Dextrose a 4 por cento . A quantificação e identificação foram feitas por meio de análises de lâminas do material microbiológico em microscópio óptico, coradas com azul de lactofenol. Para o dióxido de nitrogênio utilizou-se difusor passivo com trietanolamina como substância adsorvente e as análises foram realizadas por espectrofotometria. O difusor passivo para avaliação da concentração de benzeno é do tipo membrana, com carvão ativado como substância adsorvente e a análise por cromatografia gasosa. O tempo de exposição para estes amostradores foi de 30 dias. O PM10 foi medido com um monitor contínuo, com leitura direta. Foram instalados dois equipamentos em cada estação por um período de 7 dias. Resultados. Os estudos indicam a presença de fungos comuns com predominância para o Cladosporium sp (52 por cento ), Alternaria sp (17 por cento ) e Penicillium sp (13 por cento ) e em proporções semelhantes interna e externamente às estações. A concentração média de NO2 no interior das estações, foi de 73,9JPñ (VWHV YDORUHV Vão semelhantes às medições externas realizadas com o equipamento de Espectroscópia de Absorção por Diferencial Óptico (DOAS) e os valores medidos pela estação de monitoramento da CETESB, instalado na FSP/USP. Os valores viii máximos encontrados para o benzeno foram de 5,7JPñ QR LQWHULRU GDV estações e 6,2JPñQRDPELHQWHH[WHUQR230LQGLFRXYDORUHVHOHYDGRV sendo o valor médio, para a estação Clínicas de 312,4JPñ PHGLGRV QD SODWDIRUPDHJ/m³ no mezanino, na estação Praça da Sé verificamos a concentração de 150,9JPñ QD SODWDIRUPD GD OLQKD H JPñ QD plataforma da linha 3. Conclusões. O presente estudo possibilitou a avaliação e comparação dos níveis de poluição ambiental interno e externo às estações. A constatação da predominância de fungos comuns no ar não indica a ausência de riscos para a saúde humana, pois o seu impacto depende da suscetibilidade dos indivíduos expostos. A concentração de NO2 e benzeno encontradas no ambiente interno e externo são de mesma ordem de grandeza, o que indica que estes contaminantes têm a mesma fonte de origem. A alta concentração de PM10 representa uma maior preocupação. Para este contaminante deve-se avaliar a composição do material encontrado e seu grau de toxicidadeObjective. 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
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Falcão, Dantas Renato. "Ozonation of Emergent Contaminants". Doctoral thesis, Universitat de Barcelona, 2007. http://hdl.handle.net/10803/1534.
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ENGLISH SUMMARY:In 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.
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Lu, Qian. "Contaminants in food stuffs". Thesis, Liverpool John Moores University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388586.
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Rönn, 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.
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Obesity is a worldwide problem affecting both children and adults. Genetic, physiological, environmental, psychological, social and economic factors interact in varying degrees, influencing body weight and fat distribution and the progress of obesity. Moreover, some anthropogenic chemicals have proven to be endocrine disrupting chemicals (EDCs) with the potential to interfere with different actions of hormones in the body. EDCs may thereby disrupt homeostasis, modifying developmental, behavioral and immune functions in humans and animals, and also promoting adiposity. Because hormones generally act at low concentrations, small changes in the endocrine system may lead to extensive effects. Based on data from experimental and epidemiological studies this thesis elucidates the relationship between a large number of environmental contaminants and obesity. The experimental studies demonstrated that fructose supplementation in the drinking water resulted in unfavorable metabolic alterations such as a higher liver somatic index (LSI), an increase in plasma triglycerides and increased plasma levels of apo A-I. Fructose in combination with exposure to bisphenol A (BPA) increased liver fat content and plasma levels of apo A-I in juvenile female Fischer 344 rats. The experimental studies also showed that the retro-peritoneal fat, which in rats is a distinct fat depot easy to distinguish and dissect, correlated well with the measurements of total fat mass analyzed with MRI, and could therefore be used as a substitute for total fat mass in rats. The epidemiological studies showed that circulating levels of persistent organic pollutants (POPs) were related to fat mass measured by DXA. OCDD, HCB, TNC, DDE and the less chlorinated PCBs were positively related to fat mass, while the more highly chlorinated PCBs showed a negative association. Further, circulating levels of BPA were positively associated with levels of the hormones adiponectin and leptin, but negatively related with ghrelin, hormones which are involved in the regulation of hunger and satiety. However, serum BPA levels were not related to measures of fat mass in the elderly individuals in the PIVUS cohort. This thesis concludes that environmental contaminants such as BPA and POPs most likely are contributors, along with genetic, social and behavioral factors, to the development of obesity.
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Lommatzsch, 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.
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The contamination of foods with hydrocarbon mixtures migrating from food contact materials (FCM) was first observed for jute and sisal bags treated with batching oil in the 1990s. Since the millennium, the focus has shifted to printing inks and recycled cardboard packaging as most recognized sources for hydrocarbon contamination from FCM. Mineral oil containing printing inks can either release hydrocarbons directly from the printing of folding boxes into food or indirectly entering the recycling chain of cardboard material by printed products, such as newspapers.
The contamination of dry foods with mineral oil hydrocarbons (MOH) from recycled fiber packaging has been reported to reach up to 100 mg/kg [1]. Using LC-GC-FID technique the MOH were categorized into mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH). The molecular mass, which is assumed to be toxicological relevant, is derived from the GC retention times of accumulated MOSH in human tissues and is limited to n C16 to n-C35 [2]. MOSH is the most significant contaminant of the human body reaching 1-10 g per person, which is of particular concern since a formation of microgranulomas (causing inflammatory reactions) in the liver was observed in rats fed with saturated hydrocarbons [3]. Furthermore, some MOAH are assumed to be genotoxic analogous to polycyclic aromatic hydrocarbons [3]. In the latest draft of a German ‘Mineral Oil Regulation’ the following limits for the migration of MOH from recycled fiber are proposed: for MOSH C16-20 4.0 mg/kg, MOSH C21-35 2.0 mg/kg and for MOAH 0.5 mg per kg food [4].
Functional barriers reducing the migration of undesirable compounds from recycled cardboards (such as MOH and other contaminants) could be a part of the solution for this issue. Supporting that approach in this study, the boxes of recycled cardboard featuring a barrier layer on the internal surface or an integrated adsorbent available early in 2014 were investigated for their efficiency in reducing migration of mineral oil hydrocarbons into dry food. A practice-oriented one-year storage test was performed with wheat flakes in seven configurations: a box of virgin fibers, two boxes of unprotected recycled cardboard, three cardboards with barrier layers (a flexo-printed polyacrylate layer, a polyvinyl alcohol coating and a multilayer involving polyester) and a cardboard containing activated carbon. The highest migration of MOH (C16-24) was observed in the boxes of unprotected recycled cardboard (MOSH: 11.4 mg/kg, MOAH: 2.4 mg/kg). Of the three investigated barrier layers only two reduced migration of MOH into food below the limits of the 3rd draft of the German mineral oil ordinance (2014) until the end of shelf life. The cardboard box involving active carbon as adsorbent prevented detectable migration of mineral oil hydrocarbons (<0.1 mg/kg). In the case of virgin fiber, which was virtually free of MOH (<1 mg/kg), migration close to the proposed limits was detected (C16-24, MOSH: 1.5 mg/kg, MOAH: 0.4 mg/kg). Therefore, it has been proven that the transport box (corrugated board) substantially contributed to the transfer of MOH into food.
Plastic FCM can also release hydrocarbons, such as polyolefin oligomeric hydrocarbons (POH), into food. These POH are of synthetic nature and are formed during the polymerization process of polyolefins (150 – 3000 mg/kg in granulates of homo/hetero polymers involving ethylene and propylene). This group of synthetic contaminants contain also saturated hydrocarbons (POSH) analogous to mineral oils, but contrary no aromatic hydrocarbons. Further, a significant amount (10 – 50%) of monounsaturated hydrocarbons (POMH) was determined in the oligomeric fraction of polyolefins, which are not detectable in mineral oil products. Therefore, these POMH can be used as a marker for POH migration. A method based on two-dimensional high performance liquid chromatography on-line coupled to gas chromatography (on-line HPLC-HPLC-GC) was developed to enable the separate analysis of saturated, monounsaturated and aromatic hydrocarbons in extracts of packaging materials like polyolefins or paperboard and foods, repectively. It is an extension of the HPLC-GC method for MOSH and MOAH [1] using an additional argentation HPLC column, since normal-phase HPLC on silica gel did not preseparate saturated from monounsaturated hydrocarbons. Further, this method and comprehensive two-dimensional GC (GCxGC) was used to investigate the concentration of different oligomer types in polypropylene (PP) and polyethylene (PE) based sealing layers as well as their corresponding granulates. The analyzed sealing layers contained 180-995 mg/kg POSH and 90-435 mg/kg POMH (C16-35). Only in sealing layers involving low-density PE, oxidized polyolefin oligomers as well as cyclic oligomers (alkylated cyclopentanes and hexanes) have been detected. The transfer of POH (C16-35) from the investigated sealing layers into food can be substantial (>50%) and can reach more than 2 mg per kg food. The level of contamination depends on the oligomer content of the sealing layer, the fat content of the food, the processing temperature and the surface-volume ratio.
Hot melt adhesives are widely utilized to glue cardboard boxes used as food packaging material. The analysed raw materials of hot melts mainly consisted of paraffinic waxes, hydrocarbon resins and polyolefins. The hydrocarbon resins, functioning as tackifiers, were the predominant source of hydrocarbons of sufficient volatility to migrate via gaseous phase into dry foods. The 18 hydrocarbon resins analyzed contained 8.2-118 g/kg saturated and up to 59 g/kg aromatic hydrocarbons (C16-24). These synthetic tackfier resins, especially the oligomers ≤C24, have been characterized structurally and migration into food was estimated using a food simulant and by the analysis of real food samples. About 0.5-1.5 % of the potentially migrating substances (C16 24) of a hot melt were found to be transferred into food under storage conditions, which can result in a food contamination of approximately 1 mg/kg food in this case. The order of magnitude depends on the absolute amount of potentially migrating substances from the hot melt, the hot melt surface, contact time, amount and type of foods.
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Bressy, 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
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Núñez, Marcé Mireia. "Emerging organic contaminants in aquatic organisms". Doctoral thesis, Universitat Rovira i Virgili, 2017. http://hdl.handle.net/10803/456825.
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Aquesta Tesi Doctoral se centra en el desenvolupament de nous mètodes analítics per determinar diferents contaminants orgànics emergents, com ara productes farmacèutics de consum generalitzat, els medis iodat de contrast per a raigs-X (un altre grup de productes farmacèutics emprats en la medicina de diagnòstic), i un grup d'edulcorants d'alta intensitat en organismes aquàtics. Dues tècniques d'extracció (extracció mitjançant líquids pressuritzats i QuEChERS) van ser avaluades per extreure els compostos seleccionats i diferents neteges també van ser provades. La determinació es va realitzar mitjançant cromatografia de líquids acoblada a espectrometria de masses.D'altra banda, també es va dur a terme un estudi ecotoxicològic en l'espècie Gammarus pulex, on s' avaluà la toxicitat del triclosan en aquesta espècie i, a més a més, es van estudiar poblacions procedents de diferents ambients amb diferents graus de contaminació per determinar si la seva resistència era similar o no.Esta 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.
Książki na temat "And contaminants"
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Blais, Jules M., Michael R. Rosen i John P. Smol, red. Environmental Contaminants. Dordrecht: Springer Netherlands, 2015. http://dx.doi.org/10.1007/978-94-017-9541-8.
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Siantar, Darsa P., Mary W. Trucksess, Peter M. Scott i Eliot M. Herman, red. Food Contaminants. Washington, DC: American Chemical Society, 2008. http://dx.doi.org/10.1021/bk-2008-1001.
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Gupta, Tarun, Avinash Kumar Agarwal, Rashmi Avinash Agarwal i Nitin K. Labhsetwar, red. Environmental Contaminants. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-7332-8.
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New Jersey Drinking Water Quality Institute. Maximum contaminant level recommendations for hazardous contaminants in drinking water. [Trenton, N.J.]: The Institute, 1987.
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New Jersey Drinking Water Quality Institute. Maximum contaminant level recommendations for hazardous contaminants in drinking water. [Trenton, N.J.]: The Institute, 1995.
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Bell, Caitlin H., Margaret Gentile, Erica Kalve, Ian Ross, John Horst i Suthan Suthersan, red. Emerging Contaminants Handbook. Boca Raton : Taylor & Francis, a CRC title, part of the Taylor & Francis imprint, a member of the Taylor & Francis Group, the academic division of T&F Informa, plc, 2018.: CRC Press, 2019. http://dx.doi.org/10.1201/b22226.
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Naeem, M., Abid Ali Ansari i Sarvajeet Singh Gill, red. Contaminants in Agriculture. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-41552-5.
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Aga, Diana, i Randolph Singh. Contaminants in Water. Washington, DC, USA: American Chemical Society, 2022. http://dx.doi.org/10.1021/acsinfocus.7e5008.
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Tolerance to environmental contaminants. Boca Raton: CRC Press, 2011.
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Noble, David G. Contaminants in Canadian seabirds. [Ottawa, Ont.]: Minister of Supply and Services Canada, 1990.
Znajdź pełny tekst źródłaCzęści książek na temat "And contaminants"
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Lavado, Raul S., i Virginia Aparicio. "Contaminants". W World Soils Book Series, 251–59. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-76853-3_18.
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Heeschen, W., i F. Harding. "Contaminants". W Milk Quality, 133–50. Boston, MA: Springer US, 1995. http://dx.doi.org/10.1007/978-1-4615-2195-2_10.
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Förstner, Ulrich. "Contaminants". W Integrated Pollution Control, 81–130. Berlin, Heidelberg: Springer Berlin Heidelberg, 1998. http://dx.doi.org/10.1007/978-3-642-80311-6_3.
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Moser, Thomas J., Jerry R. Barker i David T. Tingey. "Anthropogenic Contaminants". W ACS Symposium Series, 134–48. Washington, DC: American Chemical Society, 1992. http://dx.doi.org/10.1021/bk-1992-0483.ch006.
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Sethi, Rajandrea, i Antonio Di Molfetta. "Groundwater Contaminants". W Groundwater Engineering, 169–92. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-20516-4_9.
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D'Mello, J. P. F. "Biogenic contaminants." W Introduction to environmental toxicology, 16–29. Wallingford: CABI, 2020. http://dx.doi.org/10.1079/9781789245189.0016.
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Favaro, Gabriella, i Sara Bogialli. "Environmental Contaminants". W Handbook of Dairy Foods Analysis, 881–909. Wyd. 2. Second edition. | Boca Raton : CRC Press, 2021.: CRC Press, 2021. http://dx.doi.org/10.1201/9780429342967-47.
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Rosen, Michael R. "The Influence of Hydrology on Lacustrine Sediment Contaminant Records". W Environmental Contaminants, 5–33. Dordrecht: Springer Netherlands, 2015. http://dx.doi.org/10.1007/978-94-017-9541-8_2.
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Janssen, M. "Contaminants". W Food Safety and Toxicity. CRC Press, 1996. http://dx.doi.org/10.1201/9781439821954.ch4.
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Slorach, S. "Contaminants". W EU Food Law. CRC Press, 2001. http://dx.doi.org/10.1201/9781439822982.ch5.
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Eleftherakis, John G. "Determining Valve Contaminant Sensitivity Effect Using Two Contaminants". W Earthmoving Industry Conference & Exposition. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 1991. http://dx.doi.org/10.4271/910960.
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Liu, Yanghe, Chenguang Sheng i George Agbai Nnanna. "Detection of Selected Pharmaceutical Contaminants and Removal Efficiency of Emerging Contaminants by Application of Membrane Filtration Technology". W ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-36906.
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Removal of emerging contaminants is considered to be one of the most important processes within advanced Waste Water Treatment Plants (WWTPs) system. Pharmaceutical contaminants in drinking water could potentially lead to human’s increasing risks of heart attacks, organ damage, mental health and even cancer. This paper investigates the emerging contaminant removal efficiencies of technologies employed by local WWTPs. After determining the presence of selected emerging contaminants (17β-estradiol, Acetaminophen, Carbamazepine, Diclofenac, Erythromycin, Estrone, Bezafibrate, Fluoxetine, Gemfibrozil, Ibuprofen, Lincomycin, Metoprolol, Naproxen, Ofloxacin, Sulfamethoxazole and Triclosan) in the waterbodies within the watershed of Lake Michigan in Northwest Indiana (NWI). Three of the contaminants above are chosen for lab experiments by considering their effects on human’s health and environment. A membrane filtration experiment is conducted in Purdue Water Institute (PWI) as preliminary studies on the removal of selected emerging contaminants. Meanwhile, application of Powdered Activated Carbon (PAC) and simulation of coagulation/flocculation are designed as combined experiment with membrane filtration for evaluation of feasibility of using these techniques.
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Aggarwal, S., G. Charters i D. Thacker. "Characterization and Decontamination of Contaminated Structures Using a Profiling Technology". W ASME 2003 9th International Conference on Radioactive Waste Management and Environmental Remediation. ASMEDC, 2003. http://dx.doi.org/10.1115/icem2003-4974.
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Certain radioisotopes (tritium, radium, cobalt, plutonium, and cesium) can penetrate porous concrete and contaminate the concrete well below the easily measured surface. Certain radioisotopes can penetrate concrete and contaminate the concrete well below the surface. The challenge is to determine the extent of the contamination problem and the magnitude of the problem in a real-time. Currently, concrete core bores are shipped to certified laboratories where the concrete residue is run through a battery of tests to determine the contaminants. The existing core boring operation volatilizes some of the contaminants (like tritium) and oftentimes cross-contaminates the area around the core bore site. The volatilization of the contaminants can lead to airborne problems in the immediate vicinity of the core bore. Cross-contamination can increase the contamination area and thereby increase the amount of waste generated. The goal is to avoid those field activities that could cause this type of release. The concrete profiling technology, TRUPROSM in conjunction with portable radiometric instrumentation produces a profile of radiological or chemical contamination through the material being studied. The data quality, quantity, and representativeness may be used to produce an activity profile from the hot spot surface into the material being sampled. This activity profile may then be expanded to ultimately characterize the facility and expedite waste segregation and facility closure at a reduced cost and risk. Performing a volumetric concrete or metal characterization safer and faster (without lab intervention) is the objective of this characterization technology. This way of determining contamination can save considerable time and money.
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Thome, Wendy E. R., Anne C. Basso i Sukhvinder K. Dhol. "Identification and Assessment of Trace Contaminants Associated With Oil and Gas Pipeline Abandoned in Place". W 1996 1st International Pipeline Conference. American Society of Mechanical Engineers, 1996. http://dx.doi.org/10.1115/ipc1996-1940.
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As more Alberta oil and gas fields become depleted, attention is being given to development of economically and environmentally sound abandonment procedures. The objective of this study was to identify and assess residual internal and external contaminants associated with abandoned pipelines, particularly those to be abandoned in place. Circumstances which might increase the risk of contaminant release, and other issues relating to residual pipeline contaminants, were also identified. It was found that there are thousands of different substances which could potentially be associated with abandoned pipelines. A wide range in the potential quantities of residual contaminants was also found. Of the issues identified, the effectiveness of pipeline pigging and cleaning procedures prior to abandonment was the most critical determinant of the potential quantities of residual contaminants. However, a number of trace contaminants, such as PCBs (Polychlorinated Biphenyls) and NORMs (Naturally Occurring Radioactive Materials) may remain after thorough cleaning. A brief review of the legislation and regulations from a number of jurisdictions shows that pipeline abandonment has only recently become an issue of concern. Regulations specific to abandonment are lacking, and more genera] regulations and guidelines are being applied on a contaminant-specific basis, or in terms of waste disposal requirements.
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Younan, Hua, Lo Keng Foo, N. Ramesh Rao i Z. Q. Mo. "Studies on Fingerprints of EDX, FTIR, XPS and TOF-SIMS Techniques and Applications in Failure Analysis of Wafer Fabrication". W ISTFA 2004. ASM International, 2004. http://dx.doi.org/10.31399/asm.cp.istfa2004p0474.
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Abstract In failure analysis of wafer fabrication it is difficult to identify possible sources of carbon-related contaminants as most of them are from polymers, organic and complex compounds. In this paper, the fingerprints of EDX, FTIR, XPS and TOFSIMS techniques will be introduced so as to identify sources of carbon-related contaminants. For example, Si peak (1.740 keV) can be used as a fingerprint of EDX technique to identify the ink-related contaminant from the other carbon-related contaminants. FTIR spectra of more than 10 possible materials from wafer fab and assembly processes are discussed, which may be used as the fingerprints of FTIR technique to identify carbon-related contaminants. The C=O functional group and the PDMS (PolyDimethylSiloxane) are recommended as the fingerprints of XPS and TOF-SIMS techniques to identify source of carbon-related contaminants, respectively. In this paper, some application cases will be also discussed.
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Aldi, Nicola, Nicola Casari, Mirko Morini, Michele Pinelli, Pier Ruggero Spina i Alessio Suman. "Gas Turbine Fouling: A Comparison Among One Hundred Heavy-Duty Frames". W ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/gt2018-76947.
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Over recent decades, the variability and high costs of the traditional gas turbine fuels (e.g. natural gas), have pushed operators to consider low-grade fuels for running heavy-duty frames. Synfuels, obtained from coal, petroleum or biomass gasification, could represent valid alternatives in this sense. Although these alternatives match the reduction of costs and, in the case of biomass sources, would potentially provide a CO2 emission benefit (reduction of the CO2 capture and sequestration costs), these low-grade fuels have a higher content of contaminants. Synfuels are filtered before the combustor stage, but the contaminants are not removed completely. This fact leads to a considerable amount of deposition on the nozzle vanes due to the high temperature value. In addition to this, the continuous demand for increasing gas turbine efficiency, determines a higher combustor outlet temperature. Current advanced gas turbine engines operate at a turbine inlet temperature of (1400–1500) °C which is high enough to melt a high proportion of the contaminants introduced by low-grade fuels. Particle deposition can increase surface roughness, modify the airfoil shape and clog the coolant passages. At the same time, land based power units experience compressor fouling, due to the air contaminants able to pass through the filtration barriers. Hot sections and compressor fouling work together to determine performance degradation. This paper proposes an analysis of the contaminant deposition on hot gas turbine sections based on machine nameplate data. Hot section and compressor fouling are estimated using a fouling susceptibility criterion. The combination of gas turbine net power, efficiency and turbine inlet temperature (TIT) with different types of synfuel contaminants highlights how each gas turbine is subjected to particle deposition. The simulation of particle deposition on one hundred (100) gas turbines ranging from 1.2 MW to 420 MW was conducted following the fouling susceptibility criterion. Using a simplified particle deposition calculation based on TIT and contaminant viscosity estimation, the analysis shows how the correlation between type of contaminant and gas turbine performance plays a key role. The results allow the choice of the best heavy-duty frame as a function of the fuel. Low-efficiency frames (characterized by lower values of TIT) show the best compromise in order to reduce the effects of particle deposition in the presence of high-temperature melting contaminants. A high-efficiency frame is suitable when the contaminants are characterized by a low-melting point thanks to their lower fuel consumption.
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Zlotopolsky, V. M., i T. Y. Volkova. "Ozonocatalytic Oxydation of Contaminants". W International Conference On Environmental Systems. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 1994. http://dx.doi.org/10.4271/941496.
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Boris, Jay P., i Gopal Patnaik. "Neutralization of Airborne Contaminants". W 46th AIAA Fluid Dynamics Conference. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2016. http://dx.doi.org/10.2514/6.2016-3196.
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Saparin, Norliza, Syed Mohd Hadi Syed Hilmi i Rahmat Ngteni. "Contaminants in Vegetable Oils". W Virtual 2021 AOCS Annual Meeting & Expo. American Oil Chemists’ Society (AOCS), 2021. http://dx.doi.org/10.21748/am21.557.
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Kasai, Paul H., i Vedantham Raman. "Hydrocarbon Transfer in Disk Drives". W ASME 2014 Conference on Information Storage and Processing Systems. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/isps2014-6903.
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In hard disk drives, oils used in the spindle motor or the actuator assembly are likely to be potential sources of hydrocarbon contaminants. Transfer to, and accumulation of such contaminants on the head would adversely affect its flyability. It was reported earlier that such transfer occurs more readily, the lower the vapor pressure of the contaminant is, and the lower the temperature of the ambiance is. The present study confirmed these findings. It is shown that the transfer is mediated by the disk surface area of high surface energy (openings of the carbon overcoat). Via an airflow transport process, droplets of the contaminant hydrocarbon are formed at such sites, and evolve in size till they are collected by the slider of the head.
Raporty organizacyjne na temat "And contaminants"
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Chen, Kuo-Fu. Critical contaminant/critical pathway analysis - surface water transport for nonradioactive contaminants. Office of Scientific and Technical Information (OSTI), listopad 1996. http://dx.doi.org/10.2172/477704.
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Pugh, Rebecca S., i Paul R. Becker. Sea turtle contaminants:. Gaithersburg, MD: National Institute of Standards and Technology, 2001. http://dx.doi.org/10.6028/nist.ir.6700.
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Rautman, C. A., P. G. Kaplan, M. A. McGraw, J. D. Istok i J. M. Sigda. Probability mapping of contaminants. Office of Scientific and Technical Information (OSTI), kwiecień 1994. http://dx.doi.org/10.2172/10136156.
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Riley, R. G., i J. M. Zachara. Chemical contaminants on DOE lands and selection of contaminant mixtures for subsurface science research. Office of Scientific and Technical Information (OSTI), kwiecień 1992. http://dx.doi.org/10.2172/10147081.
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Riley, R. G., i J. M. Zachara. Chemical contaminants on DOE lands and selection of contaminant mixtures for subsurface science research. Office of Scientific and Technical Information (OSTI), kwiecień 1992. http://dx.doi.org/10.2172/5202264.
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Ahn, J., C. L. Kim, P. L. Chambre, T. H. Pigford i W. W. L. Lee. Intermediate-field transport of contaminants. Office of Scientific and Technical Information (OSTI), czerwiec 1989. http://dx.doi.org/10.2172/7260188.
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Marina, Olga A., Greg W. Coffey, Christopher A. Coyle, Carolyn D. Nguyen, Edwin C. Thomsen i Larry R. Pederson. Anode Interactions with Coal Gas Contaminants. Office of Scientific and Technical Information (OSTI), sierpień 2008. http://dx.doi.org/10.2172/963244.
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Turk, B. S., T. Merkel, A. Lopez-Ortiz, R. P. Gupta, J. W. Portzer, G. N. Krishnan, B. D. Freeman i G. K. Fleming. NOVEL TECHNOLOGIES FOR GASEOUS CONTAMINANTS CONTROL. Office of Scientific and Technical Information (OSTI), wrzesień 2001. http://dx.doi.org/10.2172/793531.
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Papa, Rebecca S., i Paul R. Becker. Alaska Harbor Seal (Phoca vitulina) contaminants:. Gaithersburg, MD: National Institute of Standards and Technology, 1998. http://dx.doi.org/10.6028/nist.ir.6211.
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B. S. Turk, R. P. Gupta, S. Gangwal, L. G. Toy, J. R. Albritton, G. Henningsen, P. Presler-Jur i J. Trembly. NOVEL TECHNOLOGIES FOR GASEOUS CONTAMINANTS CONTROL. Office of Scientific and Technical Information (OSTI), kwiecień 2008. http://dx.doi.org/10.2172/1027121.
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