Microbial contamination of drinking water poses an important health risk which causes severe illnesses and epidemics. In order to improve surface and drinking water quality, the understanding of fecal pathogen contamination processes including their prevention and control needs to be enhanced. The watershed model soil water assessment tool (SWAT) is commonly used to simulate the complex hydrological, meteorological, erosion, land management and pollution processes within river basins. In recent years, it has been increasingly applied to simulate microbial contamination transport at the watershed scale. SWAT is used in this study to simulate Escherichia coli (E.coli) and fecal coliform densities for the agriculturally dominated Payne River Basin in Ontario, Canada. Unprecedented extensive monitoring data that consist of 30 years of daily hydrological data and 5 years of bi-weekly nutrient data have been used to calibrate and validate the presented model here. The calibration and validation of the streamflow and nutrients indicate that the model represent these processes well. The model performs well for periods of lower E. coli and fecal coliform loadings. On the other hand, frequency and magnitude of higher microbial loads are not always accurately represented by the model.

Microbial contamination of drinking water poses an important health risk which causes severe illnesses and epidemics. In order to improve surface and drinking water quality, the understanding of fecal pathogen contamination processes including their prevention and control needs to be enhanced. The watershed model soil water assessment tool (SWAT) is commonly used to simulate the complex hydrological, meteorological, erosion, land management and pollution processes within river basins. In recent years, it has been increasingly applied to simulate microbial contamination transport at the watershed scale. SWAT is used in this study to simulate Escherichia coli (E.coli) and fecal coliform densities for the agriculturally dominated Payne River Basin in Ontario, Canada. Unprecedented extensive monitoring data that consist of 30 years of daily hydrological data and 5 years of bi-weekly nutrient data have been used to calibrate and validate the presented model here. The calibration and validation of the streamflow and nutrients indicate that the model represent these processes well. The model performs well for periods of lower E. coli and fecal coliform loadings. On the other hand, frequency and magnitude of higher microbial loads are not always accurately represented by the model.

Aquesta Tesi Doctoral té com objectius principals l’estudi d’Helicobacter pylori en mostres aquàtiques de Catalunya, en aigües procedents de sistemes dentals de consultes de dentistes, en saliva i en femtes de pacients amb símptomes gastrointestinals mitjançant el mètode de la PCR. També es va estudiar la supervivència d’Helicobacter pylori en aigua dolça usant un model de laboratori aplicant diferents tècniques d’anàlisi i es va interpretar el canvi de morfologia, la viabilitat i la culturabilitat de la bactèria així com la detecció i quantificació del seu ADN durant un període de temps concret. Per aconseguir aquests objectius, primer es va escollir la llet descremada al 40% v/v com a millor crioprotector i el medi agar Columbia suplementat amb 5% de sang desfibrinada de cavall com a medi de cultiu. Durant el desenvolupament de la tesi es va millorar la tècnica de PCR escollida inicialment basada amb l’estudi de Clayton i col•laboradors (1992) on s’usaven els iniciadors HPU1 i HPU2 en la PCR pel gen ureA, gen estructural de l’enzim ureasa. La tècnica de la hibridació seguida per aquests investigadors es va substituir per una segona PCR ja que aquesta permetria obtenir resultats més ràpidament. En aquesta PCR semiimbricada es va introduir un tercer iniciador intern, HPUI1, i mantenint HPU2 com a extern. Pel gen 16S rRNA, gen usat per a la detecció del gènere Helicobacter, es van usar els iniciadors 1F i 1R per a la primera PCR i els 1F i 2R per a la PCR semiimbricada. El mètode d’extracció escollit en aquest treball basat en partícules de sílice i tiocianat de guanidina descrit per Boom i col., (1990) i l’optimització de les barreges de reacció de les PCR semiimbricades pel gen ureA i 16S rRNA van permetre detectar 50 UPF/mL i 2-20UFC/mL, respectivament. Es va determinar la presència de H.pylori en mostres fecals humanes aplicant dos mètodes: mètode antigènic HpSA i l’amplificació del gen ureA. Amb el mètode molecular es va detectar la presència de ADN de H. pylori en 12 mostres i va mostrar un 75% de coincidència amb els resultats obtinguts amb el mètode antigènic HpSA. També es va determinar la presència de H. pylori a aigües amb diferent de nivell de contaminació fecal. Es va amplificar ADN d’aquesta espècie en un 30% de les mostres d’aigua residual, un 8,34% de les mostres d’aigua de riu de Catalunya i no es va detectar en aigua de font. L’estudi de supervivència de H. pylori a l’aigua en la foscor i a 7ºC es va demostrar que el recompte de bacteris i el número de genomes es manté constant durant tot el període d’estudi, 21 dies. La detecció per PCR també va ser positiva i constant durant aquest període. No obstant això, les cèl•lules només es van mantenir cultivables fins al sisè dia d’emmagatzematge. També es va observar una conversió morfològica de les cèl•lules bacterianes passant de la forma espiral a cocal amb el pas del temps. L’estudi de la morfologia cel•lular en un tall vertical d’una colònia d’H. pylori de 4 dies va mostrar la coexistència de cèl•lules amb morfologia bacil•lar i coccal. L’anàlisi de la saliva de 31 persones sanes va evidenciar la presència d’aquest bacteri en la boca de 6% de la població analitzada. La anàlisi feta amb la PCR semiimbricada per al gen 16S rRNA va identificar la presència d’aquest gen en 19 persones però la seqüenciació dels amplicons del gen ureA només va confirmar la presència de H. pylori en tres mostres. L’anàlisi de 31 mostres d’aigua procedents de les corresponents cadires no va mostra la presència del patogen. / This thesis has as main objectives the study of Helicobacter pylori in water samples from Catalonia, saliva and human feces using the PCR method. Also studied survival, morpholgy, viability and culturability of Helicobacter pylori in water. We first chose skim milk at 40% v / v as cryoprotectant and Columbia agar supplemented with 5% horse blood desfibrinada as a medium. We used a seminested PCR for ureA gene with HPU1 and HPU2 primers for the first PCR and HPUI1 and HPU2 for the second PCR. By gene 16S rRNA, we used the 1F and 1R primers for the first PCR and 1F and 2R for the second PCR. Using a silica and guanidine extraction method and optimization of the seminested PCR reaction mixtures for urea and 16S rRNA genes were detected 50 UPF / mL and 2-20UFC/mL respectively. H.pylori was detected in 12 human fecal samples. DNA of H.pylori was amplified in 30% of samples of wastewater, a 8.34% of the samples of river water in Catalonia and was not detected in spring water. The bacterial count and the number of H.pylori genomes remains constant throughout the study period, 21 days water in the dark at 7 ° C. The detection by PCR was also positive and constant during this period. The cells remained culturable only until the sixth day of storage. We observed morphological conversion of bacterial cells through the spiral to cocal over time. The study of cell morphology in a vertical section of a colony of H.pylori showed the coexistence of cells with bacillary and coccal morphology. The analysis of saliva from 31 healthy individuals showed the presence of this bacterium in the mouth of 6% of the analyzed population but we urea only confirmed the presence of H.pylori in three samples by sequencing.

No description available.

A study was conducted to examine the impact of diet and cold weather on the excretion of nitrogen (N) and phosphorus (P) from beef cows, and the potential for these nutrients to be lost to waterways or as greenhouse gases (GHG). Feces and urine were collected from mature cows fed low-quality forage supplemented with DDGS to 0%, 10%, and 20% ww-1 in the fall of 2008 and winter of 2009. A detailed nutrient analysis was performed to determine forms of N and fractions of P in excreta. Feces, urine, and a simulated bedding pack were then applied to grassland to determine soil GHG emission. Cattle receiving DDGS supplementation excreted greater proportions of labile P in feces and greater concentrations of P in urine. The 20% DDGS diets had greater nitrous oxide emission from urine patches and greater proportions of available N in urine and feces.

Brominated flame retardants (BFRs) have been used in a variety of consumer products to enhance their fire safety. This has resulted in exposure of the environment, wildlife and humans causing risks of endocrine disruption. The use restrictions of many BFRs have resulted in the introduction of other brominated chemicals (emerging BFRs) on the market. Humans are exposed to BFRs primarily via diet and dust ingestion, but the importance of the different exposure pathways has scarcely been studied. Children in particular have not been studied well due to lack of biomonitoring data. In this thesis, a mother-toddler cohort (n=24) from Uppsala was studied for their exposure to tri-decabrominated diphenyl ethers (tri-decaBDEs), isomer-specific hexabromocyclododecanes (HBCDs) and emerging BFRs (EBFRs). A clean-up and fractionation method was developed for determination of the above-mentioned BFRs in the same sample without dividing the sample. Measures of external exposure from dietary intake and dust ingestion were estimated. These were compared to internal concentrations (serum, feces) to determine which exposure pathways were most important for explaining the different BFR concentrations and patterns found in mothers and toddlers. Taking all the results into account, the toddlers’ higher serum levels of tetra-pentaBDEs seem to be the result of previous breastfeeding and those of octa-decaBDEs from exposure to house dust. For mothers, diet was estimated to be the main exposure route of tri-hexaBDEs and HBCDs. Dust ingestion was estimated to be the main route for BDE-209 exposure in mothers. Significant correlations were found between the tetra-decaBDE concentrations in matched serum and feces samples indicating that feces could be used as a non-invasive sample matrix for biomonitoring of PBDEs in toddlers. EBFRs were detected in the feces of toddlers and in a few serum samples from both mothers and toddlers indicating that exposure to these replacement chemicals occurs. / <p><strong> </strong>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Submitted. Paper 4: Manuscript.</p>

Microbial contamination of drinking water poses an important health risk which causes severe illnesses and epidemics. In order to improve surface and drinking water quality, the understanding of fecal pathogen contamination processes including their prevention and control needs to be enhanced. The watershed model soil water assessment tool (SWAT) is commonly used to simulate the complex hydrological, meteorological, erosion, land management and pollution processes within river basins. In recent years, it has been increasingly applied to simulate microbial contamination transport at the watershed scale. SWAT is used in this study to simulate Escherichia coli (E.coli) and fecal coliform densities for the agriculturally dominated Payne River Basin in Ontario, Canada. Unprecedented extensive monitoring data that consist of 30 years of daily hydrological data and 5 years of bi-weekly nutrient data have been used to calibrate and validate the presented model here. The calibration and validation of the streamflow and nutrients indicate that the model represent these processes well. The model performs well for periods of lower E. coli and fecal coliform loadings. On the other hand, frequency and magnitude of higher microbial loads are not always accurately represented by the model.

A study was conducted to examine the impact of diet and cold weather on the excretion of nitrogen (N) and phosphorus (P) from beef cows, and the potential for these nutrients to be lost to waterways or as greenhouse gases (GHG). Feces and urine were collected from mature cows fed low-quality forage supplemented with DDGS to 0%, 10%, and 20% ww-1 in the fall of 2008 and winter of 2009. A detailed nutrient analysis was performed to determine forms of N and fractions of P in excreta. Feces, urine, and a simulated bedding pack were then applied to grassland to determine soil GHG emission. Cattle receiving DDGS supplementation excreted greater proportions of labile P in feces and greater concentrations of P in urine. The 20% DDGS diets had greater nitrous oxide emission from urine patches and greater proportions of available N in urine and feces.

Thesis (PhD.(Medical Virology)--Faculty of Health Sciences)-University of Pretoria, 2007. / Includes bibliographical references.

Diss. (sammanfattning) Stockholm : Karol. inst., 2005. / Härtill 5 uppsatser.