151 |
Validação e aplicação de métodos para análise de amostras de fenol em urina de trabalhadores e no ar do ambiente de trabalho / Methods validation and aplication to quantify phenol in urine and air samples in the workplaceTiago Severo Peixe 04 August 2006 (has links)
O fenol é utilizado na indústria como agente desinfetante, no preparo de resinas fenólicas e pigmentos de tintas. Apresenta-se no estado sólido à temperatura ambiente, com coloração fracamente rósea, odor acre e é higroscópico. Na exposição ocupacional aguda o composto pode levar a lesões eritematosas e sensação de calor, cronicamente, afetar a maturação celular no compartimento medular ósseo devido à formação de 1,4-benzoquinona. Os monitoramentos ambiental e biológico possuem relevância nas situações de exposições ocupacionais. O objetivo do trabalho foi validar e aplicar métodos apropriados na determinação de fenol em amostras de ar do ambiente de trabalho e urinas provenientes de trabalhadores do setor de macharia de uma indústria de peças sanitárias. Amostras de urina e ar foram analisadas, permitindo-se verificar a aplicação dos métodos cromatográficos para determinação de fenol. / Phenol is used as an industrial disinfectant agent, in the preparation of phenolic resins and paint pigments. When in solid state, it shows a light pink color, ocre odor and is hygroscopic. In acute occupational exposure, the compound can produce erythemic injuries and burn sensation and, chronically, affect the cellular maturation of bone marrow due the 1,4-benzoquinone. Environmental and biological monitoring are important in occupational exposure situations. The aim of this work was to validate a method to be applied in the determination of phenol concentration in air samples originated from work environment and urines taken from molding area workers at a sanitary devices foundry. Urine and air samples were analyzed, showing application of chromatography methods in phenol quantification.
|
152 |
Implementação da técnica de PCR Quantitativa em Tempo Real (qPCR) para o monitoramento de Microcystis e genótipos potencialmente produtores de microcistinas / Implementation of Real Time Quantitative PCR technique (qPCR) for the monitoring of Microcystis and potentially microcystin-producing genotypesLorenzi, Adriana Sturion 15 May 2008 (has links)
Florações de cianobactérias tóxicas em corpos dágua doce usados como fonte para o consumo humano, recreação e irrigação são freqüentes nos dias de hoje devido à eutrofização destes ambientes. O monitoramento de linhagens tóxicas é importante para a prevenção dos efeitos adversos causados por suas toxinas na saúde de humanos e animais. Métodos rápidos e sensíveis para a detecção precoce das cianobactérias tóxicas em estações de tratamento de água e em programas de monitoramento de mananciais são de fundamental interesse para a prevenção desses efeitos. Atualmente, contagem de células, identificação de cianobactérias por microscopia óptica e análises químicas ou imunológicas das toxinas são usadas nos monitoramentos. Em anos recentes, métodos moleculares estão sendo desenvolvidos e propostos para o diagnóstico rápido e sensível da presença de cianobactérias tóxicas em diversos ambientes. Este estudo teve por objetivo implementar uma metodologia capaz de acessar e quantificar as cianobactérias do gênero Microcystis na Praia dos Namorados, no reservatório de Salto Grande, Americana, SP, local cujo uso recreacional é bastante intenso e florações de cianobactérias são freqüentemente observadas. Simultaneamente, buscou-se detectar o potencial de produção de microcistinas desses organismos. A técnica de PCR Quantitativa em Tempo Real (qPCR) foi empregada com essa finalidade e dois conjuntos de oligonucleotídeos LUX foram desenvolvidos tendo como alvo dois genes distintos. Seqüências de cpcBA-IGS do operon da ficocianina (PC) foram obtidas para sete linhagens de cianobactérias brasileiras, as quais foram alinhadas com outras seqüências existentes em banco de dados público, e permitiram o desenho dos iniciadores de qPCR QPCF/QPCR, capazes de amplificar fragmentos de 144 pb. Da mesma forma, outras 11 sequências inéditas foram obtidas para uma região do domínio da N-methyltransferase do gene da sintetase de microcistinas (mcyA) e permitiram o desenvolvimento dos iniciadores QmcyANMTF/ QmcyA-NMTR, capazes de amplificar fragmentos de 154 pb. Ambos os conjuntos foram marcados uma única vez com os fluoróforos FAM (QPCF/QPCR) ou JOE (QmcyA-NMTF/QmcyA-NMTR). Curvas de calibração para ambos os genes foram estabelecidas com regressão linear simples usando os valores de Ct (número de ciclos da qPCR em que a fluorescência atinge um limiar fixo pré-determinado) e concentrações conhecidas de DNA gênomico (em número de células equivalente) da Microcystis sp. NPLJ-4 (produtora de microcistina). As diluições utilizadas para o estabelecimento dessas curvas variaram de 1:10 a 1:10-5 e as concentrações de DNA foram correlacionadas com o respectivo número de células na amostra, obtido pela técnica de Utermöhl em laboratório certificado, como metodologia independente. Para PC e mcyA, as equações de regressão foram y = 43,977 - 1,8097Ln(x) (R2 = 0,99, p<0,05) e y = 42,932 - 1,8449Ln(x) (R2 = 0,99, p<0,05), respectivamente, sendo y = Ct com limiar de fluorescência fixo avaliado em 0,03 e x = quantidade de DNA na amostra em concentrações conhecidas (dada como log do número de células equivalente). Para ambos os genes analisados, o limite de detecção foi de 100 células por reação. Eficiências de 79 e 76% foram alcançadas nas amplificações para PC e mcyA, respectivamente. Posteriormente, essa metodologia foi aplicada a duas outras linhagens isoladas de Microcystis e em amostras ambientais de água, que foram coletadas sempre no mesmo ponto (Praia dos Namorados), em quatro períodos distintos (dez 06, abr 07, set 07 e nov 07). Genótipos PC (em número de células mL-1) foram quantificados pela técnica de qPCR em todas as amostras analisadas. Porém, genótipos mcy puderam ser determinados apenas em M. aeruginosa NPJB1 (0,5%) e na amostra referente à primeira coleta (2,7%). Os resultados de número de células em todas as análises feitas usando a técnica de Utermöhl foram superiores aos obtidos pela qPCR. A comparação entre as médias dos valores de quantificações gerados por Utermöhl e qPCR (PC) mostrou diferença significativa (Teste t de Student, p <0,05). Nas amostras ambientais, com exceção da primeira coleta, a presença de outros gêneros de cianobactérias cocóides, como Radiocystis e Sphaerocavum, foi observada, e suas distinções não foram possíveis nas observações microscópicas após a disrupção das colônias. Estudos adicionais realizados com a região cpcBA-IGS desses outros gêneros mostraram 96% de identidade com Microcystis, e seqüências IGS bastante similares. Assim, existe a possibilidade de que os iniciadores desenhados neste estudo estejam também amplificando esses dois gêneros de cianobactérias. Em adição, a contagem em microscópio pode ter superestimado os resultados, enquanto que a técnica de qPCR mostrou baixa eficiência de amplificação. O ensaio imunológico ELISA (Enzyme-Linked Immunosorbent Assay) identificou a produção de microcistinas dos tipos LR, RR ou YR em todas as amostras com concentrações maiores que 0,1 g L-1, com exceção da M. aeruginosa NPCD1 (não produtora de microcistinas). Os resultados obtidos neste estudo indicam que o número de células de Microcystis, estimado pela técnica de qPCR pode ser usado para o monitoramento ambiental na Praia dos Namorados, em atendimento à Portaria MS 518. Além disso, demonstram que é possível inferir a proporção de genótipos mcyA a partir da determinação de genótipos PC. Contudo, a validação dessa técnica requer maiores estudos, incluindo a utilização de mais gêneros de cianobactérias e análises de outros reservatórios brasileiros, para melhor avaliar sua confiabilidade para uso no monitoramento ambiental. Para fins de monitoramento em larga escala, a técnica de qPCR mostrou-se mais viável economicamente em relação à contagem de células por microscopia, devido a sua maior capacidade de processamento (18 amostras dia-1) / Toxic cyanobacterial blooms in freshwater bodies used as a source for human consumption, recreation and irrigation are frequent nowadays due to the eutrofication of these environments. The monitoring of toxic strains is important for the prevention of the side effects caused by their toxins in human and animal health. Rapid and sensitive methods for early detection of toxic cyanobacteria in water treatment stations and aquatic monitoring programs are essential for the prevention of these effects. Currently, cells counting, cyanobacterial identification using optical microscopy and chemical or immunological analyses of the toxins are applied for monitoring purposes. In recent years, molecular approaches are being developed and proposed for rapid and sensitive diagnosis of the presence of toxic cyanobacteria in several environments.This study aimed to implement a methodology capable of access and quantify Microcystis cyanobacterial genus at the Praia dos Namorados, in the Salto Grande reservoir, Americana, SP, where recreation is very intense and cyanobacterial blooms are frequently observed. Simultaneously, it was searched to detect the potential for microcystins production by these organisms. The Real Time Quantitative PCR (qPCR) technique was employed for these purpose and two sets of LUX primers were developed to target two distinct genes. Sequences of cpcBA-IGS of the phycocyanin operon (PC) were obtained for seven Brazilian cyanobacterial strains, which were aligned with other existing public database sequences, and allowed to design the qPCR QPCF/QPCR primers, able to amplify fragments of 144 bp. In the same way, 11 novel sequences were obtained from a region of the N-methyltransferase domain of the microcystin sinthetase gene (mcyA) and allowed the development of QmcyANMTF/ QmcyA-NMTR primers, able to amplify fragments of 154 bp. Both primer sets were labeled only once with FAM (QPCF/QPCR) or JOE (QmcyA-NMTF/QmcyA-NMTR) fluorophors. Standard curves for both genes were established with simple linear regression using the Ct values (the PCR cycle numbers at which the fluorescence reaches a predetermined threshold level) and known Microcystis sp. NPLJ-4 (microcystin producer) genomic DNA concentrations (in cell number equivalents). The dilutions used for the establishment of these curves ranged from 1:10 to 1:10-5 and the DNA concentrations were correlated with the respective cell numbers of the sample, obtained by Utermöhl technique in a certified laboratory, as an independent methodology. For PC and mcyA, the regression equations were y = 43.977 - 1.8097Ln(x) (R2 = 0.99, p<0,05) and y= 42.932 - 1.8449Ln(x) (R2 = 0.99, p<0,05), respectively, where y is the Ct at the set fluorescence threshold level (0.03) and x is the amount of known DNA concentrations in the sample (given as log cell number equivalents). For both analyzed genes, the detection limit was 100 cells per reaction. Efficiencies of 79 and 76% were achieved for PC and mcyA amplifications, respectively. Subsequently, this methodology was applied to two other isolated Microcystis strains and to environmental water samples, which were collected always in the same location (Praia dos Namorados), in four different periods (Dez 06, Apr 07, Set 07 and Nov 07). PC genotypes (in cell numbers mL-1) were quantified by the qPCR technique in all analyzed samples. However, mcy genotypes could be determined only in M. aeruginosa NPJB1 (0.5%) and in the first collected sample (2.7%). The results of cell numbers in all the analyses performed using Utermöhl technique were superior then those obtained by qPCR. The comparison between the average quantification values generated by Utermöhl and qPCR (PC) showed significant difference (Test t of Student, p<0,05). In the environmental samples, except for the first one collected, the presence of other cocoid cyanobacterial genera, such as Radiocystis and Sphaerocavum, was observed, and their distinctions were not possible by microscope observation after colonies disruption. Further studies carried out with the cpcBA-IGS region of these other genera showed 96% of identity with Microcystis, and very similar IGS sequences. Then, there is a possibility that the primers designed in this study are also amplifying these two cyanobacterial genera. In addition, microscopic cells counting may have overestimated the results, whereas qPCR technique showed low efficiency of amplification. The ELISA immunological assay (\"Enzyme-Linked Immunosorbent Assay\") identified the LR, RR or YR microcystins types in all samples analysed with concentrations higher than 0.1 mg L-1, with exception of M. aeruginosa NPCD1 (no microcystin producer). The results obtained in this study suggest that Microcystis cell numbers estimated by qPCR technique can be used for the environmental monitoring of the Praia dos Namorados, in attendance to the MS 518 regulation. Furthermore, they demonstrate that it is possible to infer the mcyA genotypes proportion from the PC genotypes determination. However, further studies are required for the validation of this technique, including the use of more cyanobacterial genera and other Brazilian reservoirs analyses, to better evaluate the reliability for its use in the environmental monitoring. For large scale monitoring, the qPCR technique is more economically viable when compared to the microscopic cells counting, due to its large processing capacity (18 samples day-1)
|
153 |
Improving Public Health through Reducing Fine Particulate Matter PollutionLi, Ying 01 March 2015 (has links)
No description available.
|
154 |
Indirect Greenhouse Gas Dynamics in Karst Groundwater Systems under Agricultural Land UseAntle, Stacy Wayne 01 October 2018 (has links)
Greenhouse gases (GHGs) are a major global environmental concern, because their concentrations have continuously increased over the past few centuries, due to global population growth, fossil fuel dependency, and the Industrial Revolution. Since these gases are naturally occurring phenomena, they will never be completely eliminated. Efforts to reduce them span numerous scientific attempts, with minimal improvements in reducing their atmospheric concentrations. In agricultural land practices, greenhouse gases are common byproducts that affect the atmosphere and, potentially, the groundwater where livestock and fertilizers are key contributors. Little is known about the fate of such greenhouse gases in dissolved form, known as indirect greenhouse gases, especially (CH4 and N2O) in karst landscapes. At Crumps Cave, indirect greenhouse gases were analyzed for seasonal changes along with other geochemistry parameters to identify if anthropogenic land use effected greenhouse gases production in the epikarst and bedrock. This study revealed that CO2 flux is mainly controlled by natural vegetation and seasonal influences. In contrast, CH4 is produced and consumed continuously in the epikarst and bedrock, where decay of organic matter is the primary driver for seasonal change and temperature has little effect on methanogens and methanotrophs survival, because of their ability of adaptation to the environment. N2O, via the nitrogen cycle in which nitrification/denitrification occurs, is directly affected by land use during fertilizer
application and crop rotation. Nitrates from the surface provide a nitrogen source for denitrification to occur and produce elevated N2O in the groundwater system, because residence time is decreased and dissolved oxygen is elevated. Indirect greenhouse gases are linked to karst groundwater systems, where they may be transported and stored in karst aquifers under agricultural land use practices through complex interactions of groundwater recharge, microbial activity, and seasonal land use variability.
|
155 |
EVALUATION OF A FILTRATION SORBENT FOR REMEDIATION OF ARSENIC IN GROUNDWATERDo, Clement 01 June 2017 (has links)
A commercially available product, PURA PhosLock, was identified and evaluated for use as a sorbent to remove dissolved arsenic (As) from drinking water. Although marketed as a product to remove phosphate in aquaria, it is composed of iron oxide hydroxide (i.e., FeO(OH)), which is also known to adsorb dissolved As species from water. Arsenic was measured using standard methods and Graphite Furnace Atomic Absorption Spectroscopy. A first rough filtration test was performed to see if the PhosLock adsorbed As well. About 50 g of PhosLock was used to filter 10 L of tap water containing 100 ppb As. No detectable As was observed in the filtrate. A sorption study was then performed to determine the time required to reach equilibrium, which was attained after seven hours. A second set of sorption studies were performed using different As concentrations and the data was evaluated using the Langmuir adsorption model. The model predicted a maximum adsorption capacity of 457 to 636 mg/g. A final flowing water column breakthrough experiment was performed. Tap water spiked with 50 ppb was filtered through 0.5 grams of sorbent in a glass chromatography column. The results showed that seven liters of water were filtered before any As was detected. Over 10 L were filtered before the maximum contaminant level ( MCL) of 10 ppb was exceeded. The flow through study results showed that the PhosLock has an As adsorption capacity of 700 mg/g. This is consistent with the highest sorption capacity predicted by the Langmuir model. The results of this study show that PhosLock is a very effective and economical sorbent for the removal of As from drinking water.
|
156 |
Remediation of Soil Hydrophobicity on a Coastal USGA Sand-Based Golf GreenThompson, Troy David 01 June 2010 (has links)
Managing soil hydrophobicity caused by localized dry spots (LDS) on sand based golf greens has become one of the greatest challenges for golf course superintendents and managers, especially as water restrictions intensify. The purpose of this study was to evaluate the effectiveness of thirteen soil surfactants in eliminating LDS and in maximizing root zone soil moisture on a sand based USGA golf green located on the California Central Coast. Potential water repellency of air dried cores (measured utilizing the water droplet penetration time (WDPT) method), phytotoxicity, and climate were analyzed during two experimental trials. Phytotoxicity data was collected for Trial I using visual quality ratings and for Trial II using a chlorophyll meter. Phytotoxicity decreased during Trial I. Differences in phytotoxicity as measured using chlorophyll index were not at all significant during Trial II (p = 1). Ten of the thirteen wetting agent treatments significantly (p < 0.001) decreased soil hydrophobicity compared with the other wetting agent treated plots and the non-treated control. More frequent application of Cascade Plus resulted in a more significant reduction in soil hydrophobicity. Increasing the application rates also resulted in the reduction of soil hydrophobicity. Wetting agent treatment 6-CP(10day) maintained the highest volumetric water content (VWC) but treatment 13-2079337 maintained the highest levels for wetting agents treated monthly.
|
157 |
Engaging communities to reduce toxic exposures with a field kit for mapping soil lead in Peru and New YorkLandes, Franziska Christine January 2019 (has links)
Lead is a global health hazard and reducing environmental exposures to lead is becoming increasingly important as negative health impacts are documented at lower levels of exposure. Soils, an important source of lead exposure in children, represent a largely untested reservoir of accumulated past and present lead contamination retained in the surface. Concentrations of soil lead are very spatially heterogeneous, however, and testing is required to identify whether site-specific soils present a hazard. In this dissertation I outline the several ways to increase testing and awareness about soil-lead contamination to provide individuals with the information needed to prevent exposure to soil lead. Chapter one presents a new field procedure for use by the general public to screen soils for hazardous levels of lead that is based on determining bioaccessible lead. Chapter two describes the delineation of soil-lead hotspots in four mining-impacted towns in Peru and reveals that parents using the field procedure identified a hotspot missed by previous testing. In this study, we find child blood lead information is associated with parent cleanliness, which may represent a pathway for child exposure to dust and soil lead, although no associations are seen directly with soil lead concentrations. In chapter three, Peruvian high school students use the field procedure in their science classes to identify hotspots of soil lead and share this information with their community. Finally, chapter four highlights that extremely elevated concentrations of soil lead are not limited to far-off mining communities but are also present locally in New York City. Soil core data collected does not reveal a single source or blanket atmospheric inputs, but rather highlights the variability of deposition that requires widespread testing.
|
158 |
Enhancing analytical capability of piezoelectric quartz crystal and capillary electrophoresis in environmental analysis using polymerase chain reaction, molecularly imprinted polymers and nanotechnologySun, Hui, January 2006 (has links)
Thesis (Ph. D.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.
|
159 |
A Gill Filament EROD Assay : Development and Application in Environmental MonitoringJönsson, Maria January 2003 (has links)
<p>A gill filament-based assay for the cytochrome P450 1A (CYP1A)-catalysed activity ethoxyresorufin <i>O</i>-deethylase (EROD) was developed in rainbow trout (<i>Oncorhynchus mykiss</i>) and applied to Atlantic salmon (<i>Salmo salar</i>), Arctic charr (<i>Salvelinus alpinus</i>), Atlantic cod (<i>Gadus morhua</i>), saithe (<i>Pollachius virens</i>), and spotted wolffish (<i>Anarhichas minor</i>). Exposure to waterborne β-naphthoflavone (βNF; 10<sup>-6</sup> M) induced branchial EROD activity in all species but the spotted wolffish. In rainbow trout exposed to low concentrations of benzo[a]pyrene (BaP; 10<sup>-9</sup> M) and the textile dye indigo (10<sup>-8</sup> M) the gills responded more rapidly than the liver to BaP, and indigo induced branchial but not hepatic EROD activity.</p><p>A CYP1A-dependent BaP adduct formation was shown in gills of fish exposed to waterborne <sup>3</sup>H-BaP, i.e. the adduct formation was enhanced by βNF and blocked by ellipticine (CYP1A inhibitor). The predominant location for BaP adducts was the secondary lamellae (most exposed part of the gill filament), whereas the CYP1A enzyme was also present in the primary lamellae of the gill filament. Hence, in addition to the cell-specific expression of CYP1A an important determinant for the localisation of adducts seemed to be the bioavailability of BaP. This idea is supported by the fact that the CYP1A enzyme was induced only in secondary lamellae by BaP (10<sup>-7</sup> M) and indigo (10<sup>-6</sup> M), whereas it was induced in both primary and secondary lamellae by 3,3´,4,4´,5-pentachlorobiphenyl (10<sup>-8</sup> M). Apparently, readily metabolised inducers (BaP and indigo) are biotransformed in the secondary lamellae.</p><p>My results show that gill filament EROD activity is a sensitive biomarker of exposure to waterborne dioxin-like pollutants, and that the assay has potential for use in monitoring. Furthermore, the results suggest that readily metabolised dioxin-like compounds absorbed via the gills may undergo first-pass metabolism in the gill cells and therefore remain undetected by monitoring of EROD activity in the liver.</p>
|
160 |
Fecal Bacteroidetes host distributions and environmental source trackingDick, Linda K. 16 November 2004 (has links)
Contamination of recreational and shellfish waters with fecal pollution is a
major water quality issue with associated economic impacts and human health risks.
Reliable fecal source identification and rapid, quantitative analyses are essential
components of risk assessment. Enteric bacteria that are endemic to specific hosts
have a potential role as public health indicators of fecal pollution. Building on
previous work to discriminate ruminant and human fecal contamination, we cloned
class Bacteroidetes 16S rRNA genes from pig, elk, dog, cat, and seagull fecal DNAs.
Unique restriction patterns were identified among clones from each of the host species
using Terminal Restriction Fragment Length Polymorphisms (T-RFLP). Clones
exhibiting unique patterns were sequenced and analyzed phylogenetically, along with
human, horse, and cattle sequences recovered from previous work. The analysis
revealed both endemic and cosmopolitan (global) host distributions. The sequence
data were used to identify host-specific genetic markers for pig and horse feces, and
to design PCR primers that identify these sources of fecal pollution in water. There
was a high degree of sequence overlap among the fecal Bacteroidetes of wild and
domestic ruminants, and among human, domestic pet, and seagull Bacteroidetes. We
compared fecal Bacteroidetes rRNA genes from these hosts using subtractive
hybridization, a method that identifies differences between closely related genomes or
gene sequences. A Bacteroidetes rDNA marker that distinguishes elk and cow feces
was identified, as well as a host-specific marker for dog fecal Bacteroidetes. The four
newly designed PCR primers were tested for specificity and sensitivity, and the dog
primer was successfully used, along with the human and ruminant-specific primers, in
a collaborative study comparing fecal source tracking methods. We also developed a
real time Taq nuclease assay for quantification of fecal Bacteroidetes 16S rDNA, and
compared it with an EPA-approved enumeration method for the current standard
public health indicator, Escherichia coli, in serial dilutions of sewage primary influent.
There was a strong, positive correlation between the methods, and the Taq nuclease
assay was sensitive and much more rapid than the E. coli assay. PCR source
identification and enumeration of fecal Bacteroidetes 16S rDNA show promise for
application in a health risk-based analysis of fecal pollution. / Graduation date: 2005
|
Page generated in 0.158 seconds