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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Evaluation of Well Seal Integrity and Its Relative Importance in Assessing Groundwater Quality

St-Germain, Pascale L. January 2011 (has links)
Unlike municipal water supplies, provincial regulations do not require systematic testing of domestic well water, which may adversely impact local residents should contamination occur. Private wells are typically shallow relative to municipal wells, and thus, are particularly vulnerable to sources of surficial contamination if preferential recharge pathways such as natural fractures or faulty seals are present. In order to determine the relative importance of well seal integrity as a preferential pathway, a practical detection method was developed based on infiltrometry. This method successfully detected faulty well seals in a wide range of geological settings across Canada, including: Hobbema, Alberta; Lindsay, Ontario; and Chelsea, Québec. It was most successful in areas of minimal heterogeneity and where the surficial geology is composed of fine-grained sediments. The community of Chelsea (Québec) was also the primary study site to examine a range of factors affecting water quality including physical characteristics, faulty well seals, other anthropogenic activities and seasonality. Water samples were collected over a period of 14 months and analyzed for bacteria and major-ion chemistry. The results show that the consideration of physical features alone is not enough to predict vulnerability in the study area. Seasonal fluctuations in ionic concentrations (e.g. ionic strength, NO3-N and Cl-) and coliform bacteria are observed and result from disperse and rapid recharge events. Multivariate analysis techniques (e.g. principal components analysis and hierarchical cluster analysis) demonstrate that preferential recharge pathways and anthropogenic activities, such as domestic effluents affect the groundwater quality. The data and findings of this study were used to assist in the design of a probabilistic risk assessment model based on the Poisson distribution. This study demonstrates the complexity and the challenges related to bacterial contamination in drilled wells. In spite of these challenges, this analysis was useful as a baseline to assess the impact of anthropogenic activities, and may be used in future studies to assist municipalities in the evaluation and protection of groundwater supplies.
12

Characterization of Coliform Bacteria in Drinking Water Treatment Plant

Westöö, Oskar January 2021 (has links)
Termen koliforma bakterier beskriver en grupp indikatororganismer som används för att bedöma renligheten och integriteten hos reningsverk samt distributionssystem som nyttjas vid dricksvattenproduktion. För närvarande ställer styrande förvaltningsmyndigheter endast krav på detektion av antalet koliforma bakterier i dricksvatten via odlingsbaserade metoder. Dessa odlingsbaserade metoder särskiljer och upptäcker koliforma bakterier, och Escherichia coli specifikt, baserat på deras tillväxt samt enzymatiska aktivitet på selektiva kromogena och fluorogena agarplattor. Den definition av koliforma bakterier som dessa lagstiftningar ger upphov till identifierar endast koliforma bakterier baserat på deras metabolism och enzymatiska aktivitet, vilket är otillräckligt för att taxonomiskt identifiera olika bakterier inom denna grupp. För att uppnå detta krävs en definition baserad på fylogenetik. Detta masterexamensarbete beskriver undersökandet av metoder för taxonomisk identifiering av koliforma bakterier baserade på en kombination av odlingsbaserade och molekylära metoder. Vattenprover från Mälaren och Lovös vattenverk i Stockholm användes för att isolera koliforma bakterier via membranfiltrering, följt av odling på selektiva medier. De isolerade kolonierna och membranfiltrerna användes för att extrahera genomiskt DNA, följt av amplifiering av specifika gener associerade med E. coli och koliforma bakterier via PCR. Dessa inkluderade lacZ-genen, uidA-genen, yaiO-genen och 16S rRNA-genen. Produkterna från lyckade genamplifieringar sekvenserades för att taxonomiskt klassificera sekvenserna och identifiera olika koliforma bakterier. Två vattenprover med inloppsvatten skickades även för metagenomisk analys av dess mikrobiom. Dessa resulta indikerade att ett odlingssteg var nödvändigt för att producera tillräckligt med biomassa och genomiskt DNA för att lyckas med genamplifieringar utan att behöva filtrera enorma mängder vattenprover. De utvalda primrarna uppvisade även varierande framgång i att amplifiera målgenerna hos koliforma bakterier. Bakteriekoloniernas fysiska utseende på de selektiva agarplattorna och resultaten från genamplifieringarna uppvisade inte sammanhängande resultat, vilket indikerar ett behov av att ytterligare undersöka och optimera de utförda PCR-protokollen. Trots detta visade metoden potential för taxonomisk identifiering av koliforma bakterier. 16S rRNA-gensekvenserna möjliggjorde identifieringen av potentiella kontaminanter som grampositiva bakterier (Micrococcus and Staphylococcus) och andra, icke-koliforma, gramnegativa bakterier (Pseudomonas and Aeromonas) på de selektiva agarplattorna. Denna information kombinerat med bakteriekoloniernas utseende på agarplattorna och resultaten från övriga genamplifieringar kan möjliggöra ett sätt att skilja på falska positiva, falska negativa, sanna positiva och sanna negativa resultat från nuvarande detektionsmetoder för koliforma bakterier. Ytterligare optimering av olika aspekter av metoderna och arbetsflödet kring identifiering av koliforma bakterier är nödvändig innan man kan införa ett liknande tillvägagångssätt i ett reningsverk. / The term coliform bacteria describes a group of indicator organisms used to measure the cleanliness and integrity of drinking water treatment plants and distribution systems. Currently, the only legal requirement set by government agencies pertains to the detection and enumeration of these bacteria via cultivation-based methods. These methods distinguish coliform bacteria and Escherichia coli based on their growth and enzymatic activity on selective chromogenic and fluorogenic agar plates. However, the legislative definition concerning their metabolism and enzymatic production is insufficient to identify bacteria within this group taxonomically. Instead, a definition based on phylogenetics is required. This master’s thesis describes the exploration of methods for the characterization and identification of coliform bacteria via a combination of cultivation-based and molecular methods. Water samples from Lake Mälaren and the Lovö drinking water treatment plant in Stockholm were used to isolate coliform bacteria via membrane filtration and cultivation on a selective agar medium. The isolated colonies and filtered membranes were subjected to DNA extraction, followed by gene amplification of target genes associated with E. coli and coliform bacteria via PCR. This included the lacZ gene, the uidA gene, the yaiO gene, and the 16S rRNA gene. Successful gene amplicons were sent for sequencing to assign taxonomic values to the sequences and identify coliform bacteria. Two inlet water samples were also sent for metagenomic analysis of the microbiome. An incubation step was necessary to gather enough biomass to extract sufficient genomic DNA for gene amplifications and avoid the need to filtrate large volumes of water. The selected primer pairs exhibited various degrees of success in amplifying the targeted genes of coliform bacteria. The physical appearance of coliform colonies on the selective chromogenic agar plates and the results from the gene amplifications displayed no discernable pattern, indicating the need to further investigate and optimize the PCR procedures. However, the method indicated a potential for coliform bacteria identification. 16S rRNA gene sequences allowed for the distinction of potential contaminants on the selective agar media in gram-positive bacteria (Micrococcus and Staphylococcus) and other non-coliform, gram-negative bacteria (Pseudomonas and Aeromonas). In conjunction with the physical appearance of bacterial colonies on selective media and successful gene amplicons of the targeted genes, this information could allow one to distinguish between false positive, false negative, true positive, and true negative results from current coliform detection and enumeration methods. Further optimization of various aspects of the coliform bacteria identification methods is necessary before introducing a similar approach to a water treatment plant context.
13

Associations between Fecal Indicator Bacteria Prevalence and Demographic Data in Private Water Supplies in Virginia

Smith, Tamara L. 12 June 2013 (has links)
Over 1.7 million Virginians rely on private water systems to supply household water. The heaviest reliance on these systems occurs in rural areas, which are often underserved in terms of financial resources and access to environmental health education. As the Safe Drinking Water Act (SDWA) does not regulate private water systems, it is the sole responsibility of the homeowner to maintain and monitor these systems. Previous limited studies indicate that microbial contamination of drinking water from private wells and springs is far from uncommon, ranging from 10% to 68%, depending on type of organism and geological region. With the exception of one thirty-year old government study on rural water supplies, there have been no documented investigations of links between private system water contamination and household demographic characteristics, making the design of effective public health interventions, very difficult. The goal of the present study is to identify potential associations between concentrations of fecal indicator bacteria (e.g. coliforms, E. coli) in 831 samples collected at the point-of-use in homes with private water supply systems and homeowner-provided demographic data (e.g. homeowner age, household income, education, water quality perception). Household income and the education of the perceived head of household were determined to have an association with bacteria concentrations. However, when a model was developed to evaluate strong associations between total coliform presence and potential predictors, no demographic parameters were deemed significant enough to be included in the final model. Of the 831 samples tested, 349 (42%) of samples tested positive for total coliform and 55 (6.6%) tested positive for E. coli contamination. Chemical and microbial source tracking efforts using fluorometry and qPCR suggested possible E. coli contamination from human septage in 21 cases.  The findings of this research can ultimately aid in determining effective strategies for public health intervention and gain a better understanding of interactions between demographic data and private system water quality. / Master of Science
14

Vliv aktivity vody na obsah mikroorganizmů ve vybraných masných výrobcích / The influence of water activity on the microbiological content in meat products

BURIANOVÁ, Michaela January 2019 (has links)
The aim of this thesis is to monitor how the amount of water (water activity) affects the amount of microorganisms is selected packaged meat products from the point of view standards, which specify their specific requirements for the health safety of these products. The first part of this work describes various types of packaging materials of meat products, the microorganisms that occur in them and the definition of water activity. The second part describes the actual measurement of water activity and the measurement of the occurrence of microorganisms and coliforms, from selection of suitable meat products, their types of packaging, sample preparation and evaluation of measured methods. The results showed, that the activity of water affects the occurrence of microorganisms and coliforms, in that the higher the activity of water, the higher microorganisms presence.
15

Avaliação da utilização de colifagos como indicadores virais a partir da análise de enterovírus e adenovírus em efluentes tratados por diferentes processos biológicos

Silva, Maria Cristina de Almeida January 2010 (has links)
Os esgotos domésticos contêm uma alta quantidade de bactérias e outros organismos patogênicos e não patogênicos que são descarregados em corpos hídricos. A contaminação da água, pela presença de bactérias e vírus patogênicos, traz conseqüências indesejáveis, principalmente de saúde pública. O objetivo deste trabalho foi avaliar a possibilidade de emprego da análise de colifagos, como indicador viral. Para isso, amostras de esgoto bruto, efluente tratado por reator UASB e efluente de lodo ativado, da Estação de Tratamento de Esgotos São João Navegantes, Porto Alegre, foram coletadas durante o período de junho/2006 a junho/2007. As análises físicas, químicas e microbiológicas, DBO5, turbidez, sólidos totais, quantificação de coliformes totais, fecais e de colifagos foram realizadas em 99 amostras, conforme APHA, 2005. Na determinação da presença de adenovírus e enterovírus foram testadas 36 amostras, utilizando-se a técnica de concentração por filtração-eluição e ultracentrifugação. Posteriormente, purificação e avaliação da infectividade. Por fim, as amostras foram submetidas a teste de nested PCR e RT-PCR, a fim de verificar a presença de adenovírus e enterovírus, respectivamente. Nas 36 amostras testadas, a presença de enterovírus foi confirmada em apenas 5,56% das amostras e, adenovírus, em 16,67% das amostras. Não foram encontradas correlações significativas entre colifagos e bactérias coliformes totais e fecais, bem como entre colifagos e os parâmetros físicos e químicos. Desta independência encontrada entre vírus e bactérias se destaca a necessidade de monitoramento conjunto de ambos os microrganismos. Verificou-se uma similaridade em relação à sazonalidade referente ao comportamento de colifagos e o descrito na literatura referente a vírus entéricos. Observou-se, também, a baixa eficiência do tratamento para remoção de microrganismos, ressaltando-se a importância de realização de um tratamento terciário para assegurar a qualidade microbiológica do efluente. As relações entre colifagos e vírus entéricos não foram possíveis de serem analisadas, devido aos dados inconclusivos obtidos no presente trabalho. / Domestic sewage contains a high amount of bacteria and other pathogens and non pathogens that are discharged into water bodies. Contamination of water by the presence of pathogenic bacteria and viruses, brings undesirable consequences, especially for public health. The objective of this work was to evaluate the possibility of using analysis of coliphages as viral indicator. Samples of raw sewage, treated effluent by UASB reactor and by activated sludge, from Wastewater Treatment Systems São João Navegantes, Porto Alegre, were collected during the period of june/2006 to june/2007. Physical, chemical and microbiological analyzes, namely BOD5, turbidity, total solids, quantification of total coliforms, fecal coliforms and coliphages were performed in 99 samples, following the techniques described in APHA 2005. The presence of enteric viruses was tested on 36 samples. The technique of concentration by filtration-elution and ultra-centrifugation was used for this purpose. Subsequently, purification and infectivity test was performed. The samples were tested to nested PCR and RT-PCR to verify the presence of adenovirus and enterovirus, respectively. In 36 samples tested, the presence of enteroviruses was confirmed in only 5.56% of the samples, and adenovirus, in 16.67% of the samples. No significant correlation was found among coliform bacteria and coliphages, and also between the presence of coliphages and physical and chemical parameters. The independence found between viruses and bacteria indicates the need for joint monitoring of both microrganisms. The behavior of coliphages was observed to follow the path described in the literature about enteric viruses in relation to seasonality. There was observed a low efficiency in terms of microorganisms removal, emphasizing the need for a tertiary treatment to ensure the microbiological quality of the effluents tested. Relations between coliphages and enteric viruses were not able to be analyzed, due to inconclusive data obtained in this work.
16

Avaliação da utilização de colifagos como indicadores virais a partir da análise de enterovírus e adenovírus em efluentes tratados por diferentes processos biológicos

Silva, Maria Cristina de Almeida January 2010 (has links)
Os esgotos domésticos contêm uma alta quantidade de bactérias e outros organismos patogênicos e não patogênicos que são descarregados em corpos hídricos. A contaminação da água, pela presença de bactérias e vírus patogênicos, traz conseqüências indesejáveis, principalmente de saúde pública. O objetivo deste trabalho foi avaliar a possibilidade de emprego da análise de colifagos, como indicador viral. Para isso, amostras de esgoto bruto, efluente tratado por reator UASB e efluente de lodo ativado, da Estação de Tratamento de Esgotos São João Navegantes, Porto Alegre, foram coletadas durante o período de junho/2006 a junho/2007. As análises físicas, químicas e microbiológicas, DBO5, turbidez, sólidos totais, quantificação de coliformes totais, fecais e de colifagos foram realizadas em 99 amostras, conforme APHA, 2005. Na determinação da presença de adenovírus e enterovírus foram testadas 36 amostras, utilizando-se a técnica de concentração por filtração-eluição e ultracentrifugação. Posteriormente, purificação e avaliação da infectividade. Por fim, as amostras foram submetidas a teste de nested PCR e RT-PCR, a fim de verificar a presença de adenovírus e enterovírus, respectivamente. Nas 36 amostras testadas, a presença de enterovírus foi confirmada em apenas 5,56% das amostras e, adenovírus, em 16,67% das amostras. Não foram encontradas correlações significativas entre colifagos e bactérias coliformes totais e fecais, bem como entre colifagos e os parâmetros físicos e químicos. Desta independência encontrada entre vírus e bactérias se destaca a necessidade de monitoramento conjunto de ambos os microrganismos. Verificou-se uma similaridade em relação à sazonalidade referente ao comportamento de colifagos e o descrito na literatura referente a vírus entéricos. Observou-se, também, a baixa eficiência do tratamento para remoção de microrganismos, ressaltando-se a importância de realização de um tratamento terciário para assegurar a qualidade microbiológica do efluente. As relações entre colifagos e vírus entéricos não foram possíveis de serem analisadas, devido aos dados inconclusivos obtidos no presente trabalho. / Domestic sewage contains a high amount of bacteria and other pathogens and non pathogens that are discharged into water bodies. Contamination of water by the presence of pathogenic bacteria and viruses, brings undesirable consequences, especially for public health. The objective of this work was to evaluate the possibility of using analysis of coliphages as viral indicator. Samples of raw sewage, treated effluent by UASB reactor and by activated sludge, from Wastewater Treatment Systems São João Navegantes, Porto Alegre, were collected during the period of june/2006 to june/2007. Physical, chemical and microbiological analyzes, namely BOD5, turbidity, total solids, quantification of total coliforms, fecal coliforms and coliphages were performed in 99 samples, following the techniques described in APHA 2005. The presence of enteric viruses was tested on 36 samples. The technique of concentration by filtration-elution and ultra-centrifugation was used for this purpose. Subsequently, purification and infectivity test was performed. The samples were tested to nested PCR and RT-PCR to verify the presence of adenovirus and enterovirus, respectively. In 36 samples tested, the presence of enteroviruses was confirmed in only 5.56% of the samples, and adenovirus, in 16.67% of the samples. No significant correlation was found among coliform bacteria and coliphages, and also between the presence of coliphages and physical and chemical parameters. The independence found between viruses and bacteria indicates the need for joint monitoring of both microrganisms. The behavior of coliphages was observed to follow the path described in the literature about enteric viruses in relation to seasonality. There was observed a low efficiency in terms of microorganisms removal, emphasizing the need for a tertiary treatment to ensure the microbiological quality of the effluents tested. Relations between coliphages and enteric viruses were not able to be analyzed, due to inconclusive data obtained in this work.
17

Avaliação da utilização de colifagos como indicadores virais a partir da análise de enterovírus e adenovírus em efluentes tratados por diferentes processos biológicos

Silva, Maria Cristina de Almeida January 2010 (has links)
Os esgotos domésticos contêm uma alta quantidade de bactérias e outros organismos patogênicos e não patogênicos que são descarregados em corpos hídricos. A contaminação da água, pela presença de bactérias e vírus patogênicos, traz conseqüências indesejáveis, principalmente de saúde pública. O objetivo deste trabalho foi avaliar a possibilidade de emprego da análise de colifagos, como indicador viral. Para isso, amostras de esgoto bruto, efluente tratado por reator UASB e efluente de lodo ativado, da Estação de Tratamento de Esgotos São João Navegantes, Porto Alegre, foram coletadas durante o período de junho/2006 a junho/2007. As análises físicas, químicas e microbiológicas, DBO5, turbidez, sólidos totais, quantificação de coliformes totais, fecais e de colifagos foram realizadas em 99 amostras, conforme APHA, 2005. Na determinação da presença de adenovírus e enterovírus foram testadas 36 amostras, utilizando-se a técnica de concentração por filtração-eluição e ultracentrifugação. Posteriormente, purificação e avaliação da infectividade. Por fim, as amostras foram submetidas a teste de nested PCR e RT-PCR, a fim de verificar a presença de adenovírus e enterovírus, respectivamente. Nas 36 amostras testadas, a presença de enterovírus foi confirmada em apenas 5,56% das amostras e, adenovírus, em 16,67% das amostras. Não foram encontradas correlações significativas entre colifagos e bactérias coliformes totais e fecais, bem como entre colifagos e os parâmetros físicos e químicos. Desta independência encontrada entre vírus e bactérias se destaca a necessidade de monitoramento conjunto de ambos os microrganismos. Verificou-se uma similaridade em relação à sazonalidade referente ao comportamento de colifagos e o descrito na literatura referente a vírus entéricos. Observou-se, também, a baixa eficiência do tratamento para remoção de microrganismos, ressaltando-se a importância de realização de um tratamento terciário para assegurar a qualidade microbiológica do efluente. As relações entre colifagos e vírus entéricos não foram possíveis de serem analisadas, devido aos dados inconclusivos obtidos no presente trabalho. / Domestic sewage contains a high amount of bacteria and other pathogens and non pathogens that are discharged into water bodies. Contamination of water by the presence of pathogenic bacteria and viruses, brings undesirable consequences, especially for public health. The objective of this work was to evaluate the possibility of using analysis of coliphages as viral indicator. Samples of raw sewage, treated effluent by UASB reactor and by activated sludge, from Wastewater Treatment Systems São João Navegantes, Porto Alegre, were collected during the period of june/2006 to june/2007. Physical, chemical and microbiological analyzes, namely BOD5, turbidity, total solids, quantification of total coliforms, fecal coliforms and coliphages were performed in 99 samples, following the techniques described in APHA 2005. The presence of enteric viruses was tested on 36 samples. The technique of concentration by filtration-elution and ultra-centrifugation was used for this purpose. Subsequently, purification and infectivity test was performed. The samples were tested to nested PCR and RT-PCR to verify the presence of adenovirus and enterovirus, respectively. In 36 samples tested, the presence of enteroviruses was confirmed in only 5.56% of the samples, and adenovirus, in 16.67% of the samples. No significant correlation was found among coliform bacteria and coliphages, and also between the presence of coliphages and physical and chemical parameters. The independence found between viruses and bacteria indicates the need for joint monitoring of both microrganisms. The behavior of coliphages was observed to follow the path described in the literature about enteric viruses in relation to seasonality. There was observed a low efficiency in terms of microorganisms removal, emphasizing the need for a tertiary treatment to ensure the microbiological quality of the effluents tested. Relations between coliphages and enteric viruses were not able to be analyzed, due to inconclusive data obtained in this work.
18

Impact of Manure Land Management Practices on Manure Borne Antibiotic Resistant Elements (AREs) in Agroecosystems

Hiliare, Sheldon 03 February 2021 (has links)
Rising global antibiotic resistance has caused concerns over sources and pathways for the spread of contributing factors. Majority of the antimicrobials used in the U.S. are involved in veterinary medicine, primarily with livestock rearing. Animal manure land application integrates livestock farming and agroecosystems. This manure contains antibiotic resistant elements (AREs) (resistant bacteria, resistance genes, and veterinary antibiotics) that contribute towards antimicrobial resistance. Altering manure application techniques can reduce surface runoff of other contaminants such as excess N and P, pesticides, and hormones, that can impact water quality. Conventional tillage practices in the U.S. has reduced or stopped, making subsurface injection of manure a promising option when compared to surface application. Our research compared manure application methods, manure application seasons, cropping system, and manure-rainfall time gaps to gauge the impact on AREs in the environment. Two field-scale rainfall simulation studies were conducted along with one laboratory study. Using the injection method lowered concentrations of manure associated AREs entering surface runoff. When manure was surface applied and rainfall occurred 7 d after application, 9-30 times less resistant fecal coliform bacteria (FCB) entered surface runoff when compared to 1 d time gap for that broadcast method. Within a day of manure application, antibiotic resistance gene (ARG) profiles in soil began to differ from each other based on manure application and soil ARG richness in all manure-amended soil increased compared to the background. Runoff from injection plots contained 52 ARGs with higher abundance compared to runoff from surface applied plots. ARGs in the former were more correlated to soil and more correlated to manure in the latter. The highest antibiotic concentrations were in the injection slit soil of those plots. Antibiotic concentrations in samples corresponded positively to concentrations of resistant FCB and ARGs, and there was a positive correlation between resistant FCB and their associated ARGs (Spearman's ρ = 0.43-0.63). A CRIISPR-Cas12a assay for quantification of ARGs in environmental samples was just as precise as conventional methods. There is also potential for in-situ detection. These combined results can hopefully help farmers improve manure management practices that mitigate spread of AREs to surrounding water, crops, and soil. / Doctor of Philosophy / Rising global antibiotic resistance cause concerns over sources and pathways for the spread of contributing factors. Most of the antimicrobials used in the U.S. are involved in veterinary medicine, especially with livestock rearing. Overuse of antibiotics that are medically important to human medicine compromises the effectiveness of our medicines. Animal manure contains antibiotic resistant elements (AREs) such as resistant bacteria, resistance genes, and antibiotics) that contribute towards resistance issues. Once these AREs enter the environment, they can be taken up by crops, runoff into surface water or leached into ground water, or even reside within the animal products we consume. Altering manure application techniques is beneficial for nutrient conservation but also potentially for reducing ARE spread. With our research, we compared manure application methods, manure application seasons, cropping systems, and manure-rainfall time gaps to find ways to balance the need for manure application and the spread of resistance. We used two field-scale rainfall simulation studies along with one laboratory study. Overall, using the injection method resulted in significantly lower concentrations of manure associated AREs entering surface runoff. When manure was surface applied and rainfall occurred 7 d after application, less resistant fecal coliform bacteria (FCB) entered surface runoff when compared to the 1 d time gap for broadcast methods. Within a day of manure application, antibiotic resistance gene (ARG) profiles in soil began to differ from each other and soil ARG totals in all manure applied soil increased compared to the background. Runoff from injection plots contained more soil ARGs and runoff from surface applied plots containing more manure associated ARGs. The subsurface injection method also caused highest antibiotic concentrations in the injection slit soil of those plots. High antibiotic concentrations in samples generally meant high concentrations of resistant FCB and ARGs, and resistant FCB were also found with their associated ARGs as well. A CRISPR-Cas12a assay for quantification of ARGs in environmental samples was just as precise as conventional methods. There is also potential for onsite detection. These combined results can hopefully help farmers improve manure management practices that mitigate spread of AREs to surrounding water, crops, and soil.
19

Analýza kvality pitné vody v jižních Čechách

VRÁNEK, Ivo January 2016 (has links)
The goal of diploma thesis was a comparison of potable water indicators in representative areas of the south Bohemia. Monitored period had been from January 2012 till December 2014. Monitored parameters were microbiological indicators (Escherichia coli, coliform microbes, number of colonies at 22°C, number of colonies at 36°C, organoleptic indicators (color, turbidity, smell, taste). Physical and chemical indicators (ammonium ions, nitrates, nitrites, chemical consumption of oxygen, chlorides, conductivity, manganese, pH, sulphates, calcium and magnesium, iron). From the total complex of 1165 data, there were 23 values over the limit (1,97%) of evaluation of all monitored quality indicators (microbiological, organoleptic, physical and chemical). In evaluation of microbiological indicators, there were 6 values (1,97%) over the limit, from total 304 data. In organoleptic indicators, there was 1 value (0,44%) over the limit, from total 227 data. In evaluation of physical and chemical indicators, there were 16 values (2,52%) over the limit, from total 634 data. In total, there are 23 values which don´t meet determined limits from The Regulation No. 252/2004 and EU directives. There are these values of limits - number of colonies at 22°C, number of colonies at 36°C, turbidity, manganese, calcium and iron.
20

Analýza vybraných ukazatelů kvality vody / The analysis of selected parameters of water quality

KŘÍŽOVÁ, Iveta January 2013 (has links)
Cílem této diplomové práce je provést analýzu vybraných ukazatelů kvality pitné vody a posouzení faktorů, které ji ovlivňují. V první části jsou zachyceny vybrané mikrobiologické ukazatele, tak jak je popisuje literatura, včetně platných norem a vyhlášek. Druhá část popisuje průběh provádění vlastní analýzy, z poskytnutých materiálů akreditovanou laboratoří společnosti AGRO-LA, spol. s r. o., až po vyhodnocení získaných výsledků.

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