Bacteria are the major cause of surface water contamination in the United States. US Environmental Protection Agency (USEPA) uses the Total Maximum Daily Load (TMDL) process to regulate the E. coli loads from fecal sources in a watershed. Different point and non-point sources can contribute to the fecal contamination of a waterbody including municipal and on-site wastewater treatment plants, livestock, birds, and wildlife. Unfortunately, wildlife sources in many rural watersheds are poorly characterized. E. coli is also known to persist in waterbodies when no known fecal sources are present. In this study, E. coli from wildlife fecal material was enumerated. It was found that E. coli concentrations varied with the season the fecal samples were collected. When studying the fate of E. coli under different environmental factors, no growth was observed in soil at 4% moisture content and in water at 10 degrees C. The highest E. coli growth was recorded in water at 30 degrees C. It can be seen from these results that there was variation in the fate of E. coli under different environmental conditions. The fate of E. coli in the environment is a complex process and is influenced by many factors and their interactions, making it difficult to predict. The findings from this study along with additional studies can be used to improve the accuracy of model predictions to estimate the E. coli loads in watersheds.

When developing a Watershed Protection Plan (WPP) or a Total Maximum Daily Load (TMDL), it is often difficult to accurately assess the pollutant load for a watershed because not enough water quality monitoring data are available. According to the Texas Commission on Environmental Quality (TCEQ), there are 274 bacteria impairments in Texas water bodies out of 386 impaired water bodies. Bacteria water quality data are often more sparse than other types of water quality data, which hinders the development of WPPs or TMDLs. The Spatially Explicit Load Enrichment Calculation Tool (SELECT) was used to develop watershed protection plans for four rural watersheds in Texas that are impaired due to E. coli bacteria. SELECT is an automated Geographical Information System (GIS) tool that can assess pathogen loads in watersheds using spatial factors such as land use, population density, and soil type. WPPs were developed for four rural Texas watersheds: Buck Creek, Lampasas River, five sub watersheds of the Little Brazos River, and Geronimo Creek. A spatial watershed model was developed to simulate bacteria concentrations in streams resulting from non point sources using SELECT combined with a simple rainfall-runoff model and applied to the Geronimo Creek watershed. The watershed model applies a rainfall-driven loading function to the potential E. coli loads calculated by the output of SELECT. The simulated runoff volumes and E. coli concentrations from the model were compared to actual monthly E. coli data collected at two sampling sites near the outlet of a subwatershed. The results show how SELECT methodology was applied to each watershed and adapted based on stakeholder concerns and data availability. The highest potential contributors were identified and areas of concern were highlighted to more effectively apply best management practices (BMPs). The runoff volumes were predicted with very good agreement (E = 0.95, RSR = 0.21 to 0.22) for both sampling sites. The predicted E. coli concentrations did not agree with measured concentrations for both sites using eight different methods. The results indicate that the model does not include significant factors contributing to the transport of E. coli bacteria but can be modified to include these factors.

The risk of waterborne infections acquired from the consumption of contaminated water is related to changes in source water fecal contamination, which is often influenced by land-use and hydro-meteorological conditions in the surrounding watershed. The impact of land-use composition on surface water contamination was explored in order to determine the risk of surface water contamination associated with land-use change. Highest contamination was observed in watersheds characterized by more than 12.5% agricultural and more than 1.6% urban land (mean fecal coliform (FC) concentration of these 5 sites = 135 CFU 100ml-1 while the British Columbia (BC) raw water quality guideline = 100 CFU 100ml-1). Contamination increased exponentially, and violated BC raw water quality guidelines with greater frequency, in relation to greater agricultural land in the upstream watershed. Additional factors, such as sewage treatment plants, low dilution in smaller streams, and higher temperatures were also associated with greater contamination. These results indicate the high level of risk posed by agricultural and urban development and the need for source water protection. Fecal contamination levels in source water are also influenced by rainfall and snowmelt-induced surface runoff that transport diffuse fecal contaminants into surface water. Seasonal levels of fecal contamination in surface water was related to the watershed hydro-climatic regime for around half of the watersheds examined. Watersheds with snowmelt-dominant (SD) runoff regimes showed stronger evidence of hydro-meteorological variability driving seasonal contamination levels than those with rainfall and snowmelt-influenced (RSI) and rainfall-dominant (RD) runoff regimes, and thus are more prone to experiencing changes to seasonal variability resulting from climate change. Projected increases in mean annual temperatures of between 1.70C and 4.00C towards the end of the 21st century will alter existing runoff regimes within watersheds. For SD watersheds that remain below freezing and continue to accumulate snowpack during the cold season, transport of fecal contamination will likely occur earlier in the year with greater intensity. Fecal coliform transport in summer is likely to decrease, especially in SD watersheds in which fecal contamination is driven by summer rainfall events. Snowmelt-dominant watersheds transitioning toward a RD runoff regime will experience less contamination during spring but increased contamination during late fall and winter. The extent to which these changes in runoff regime will influence surface water fecal contamination will vary among watersheds. Further investigation is required to identify factors that enhance or mitigate the association of surface water fecal contamination with rainfall and snowmelt-induced runoff in order to identify specific site vulnerability to changing seasonal contamination levels. Total precipitation within BC is projected to increase by 20-30% towards the end of the 21st century. The association of annual FC variability with snowmelt and rainfall variability was examined in order to assess the capacity of such increases to raise the level of surface water fecal contamination. Greater total annual and seasonal rainfall and/or river discharge increased surface water fecal contamination for 58% (11/19) of the sites examined. Hydro-meteorological variability influenced FC concentration during winter, the season of greatest precipitation, and spring, the season of greatest snowmelt, but not during summer or fall. Reduced contamination levels during the El Niño event in 2002/03 were associated with a mean reduction in river discharge during spring and summer. These associations suggest that the risk of increased surface water fecal contamination in response to higher precipitation is likely to be greatest in winter for RD watersheds and spring for SD watersheds, although the magnitude of impact will vary among sites. Climate change and land-use activities within watersheds have the capacity to alter the timing and amount of surface water fecal contamination. These factors are likely to act synergistically by increasing the presence and transport of fecal contaminants within watersheds. Such relationships should be carefully considered to aid the assessment and mitigation of the risk of source water contamination associated with land-use and climate change. / Graduate

Poor sanitation infrastructure in rural areas can often lead to high levels of fecal contamination in local waterbodies and subsequent exposure to waterborne disease can occur. Although standard water quality measures such as quantification of E. coli can reveal relative concentrations of fecal contamination, they do not pinpoint the sources of such contamination. Source assessment in rural areas affected by untreated household waste might be improved with the human-specific, microbial source tracking marker HF183. This study attempted to quantify HF183 in two particular Appalachia streams with known discharges of untreated household waste. Water samples were taken above and at multiple points below these discharges on 29 occasions between August 2012 and April 2016, and tested for both HF183 and E. coli. HF183 was detected consistently in one of the study streams, though the concentrations were generally much lower than those previously reported in raw sewage; in the other watershed, HF183 was never detected. Further analysis via a multiple linear regression model showed a positive correlation between the level of E. coli and the proximity and number of known waste discharge points upstream from each sampling site. Primary conclusions of this study include: 1) HF183 is not always detected, even in watersheds with known sources of human fecal contamination, 2) it may be a useful water quality assessment tool where such contamination is suspected, particularly in cases where contaminant source allocation is necessary for setting mitigation priorities. / Master of Science

During the 1980’s millions of households in Bangladesh switched from drinking surface water to private groundwater wells to reduce their exposure to fecal microorganisms. Sadly, this switch to shallow groundwater resulted in the largest example of drinking water poisoning in history, with approximately 100 million people exposed to high concentrations of naturally occurring Arsenic in the groundwater. Spatial distribution of Arsenic in the shallow aquifers tends to be patchy, so the most economical mitigation option has been lateral switching from high Arsenic wells to nearby low Arsenic wells. The recently developed Arsenic flushing conceptual model, which explains the spatial distribution of Arsenic throughout the shallow aquifers in Bangladesh, suggests however, that low Arsenic zones are recharged via coarse-grained, rapid flow pathways and therefore represent a higher risk for waterborne pathogens. The objectives of this dissertation are to evaluate new methods for sampling and detection of waterborne pathogens, while also identifying sources of fecal contamination and transport pathway(s) to private wells emplaced within the shallow aquifers. It was demonstrated that private wells are broadly contaminated with E. coli, with prevalence ranging from 30 to 70%. The fact that E. coli was detected more frequently in private wells than sealed monitoring wells (p<0.05) suggests that well construction and/or daily pumping contribute to fecal contamination of the private wells. Using DNA-based molecular fecal source tracking, contamination was demonstrated to originate from human fecal waste. Unsanitary latrines, which spill effluent onto the open ground, were demonstrated to cause elevated levels of fecal bacteria in ponds, found in every village. These ponds were demonstrated to have an influence on concentrations of fecal bacteria to at least distances of 12m into the adjacent aquifer. In a culture where latrines, private wells and ponds are frequently clustered closely together, these findings suggest that improvements in the management of human fecal waste changes in placement and construction of private wells could substantially reduce exposure of people to fecal pathogens. Fecal contamination was found to be pervasive in low Arsenic, unconfined, shallow aquifers, and therefore gains from well switching to avoid Arsenic need to be balanced with the risk of consuming waterborne pathogens.

Orientador: Luiz Augusto do Amaral / Banca: Elma Pereira dos Santos Polegato / Banca: Maria da Gloria Buzinaro / Resumo: Realizou-se o presente estudo objetivando-se conhecer a dinâmica da contaminação fecal e uso do cloro na desinfecção da água oferecida a bezerras em propriedade leiteira, pela determinação do número mais provável - NMP de enterococos e Escherichia coli, do número de microrganismos mesófilos, concentração de cloro, pH e temperatura. O manejo das bezerras era realizado em locais coberto e não coberto. Cada manejo utilizou dez bebedouros: cinco com água não clorada e cinco com clorada. No local não coberto a água sofria uma troca diária, estando 24 horas à disposição das bezerras, e era amostrada após sua colocação (T0), após 17 horas (T1) e 24 horas (T2). No local coberto ocorriam duas trocas diárias da água, estando 17 horas, na 1ª troca e 7 horas na 2ª troca à disposição das bezerras e as colheitas eram feitas após a colocação da água na 1ª troca (T0), após 17 horas (T1), após a colocação na 2ª troca (T0) e após 7 horas (T1). Na estação de chuva realizaram-se três amostragens com cinco repetições cada, na seca, três amostragens, as duas primeiras com cinco repetições e a última com três. A cloração reduziu significativamente os NMP de enterococos e E. coli e os números de microrganismos mesófilos em todas amostras de águas cloradas. O melhor manejo da água de consumo das bezerras foi em local coberto, com cloração (5,0 mg.L-1) e troca da água três vezes ao dia. / Abstract: The objective of the study was to evaluate fecal contamination dynamic and use of chlorine on the disinfection of the offered water for calves in a dairy farm, through the most probably number determination (MPN) of enterococcus, Escherichia coli and determination of the mesophilic microorganisms, chlorine demand, pH and temperature. The calves’ management was at no covered and covered place. Ten watering though, five with chlorinated water and five with no chlorinated water were used in each one of the managements. At the no covered place, water was changed once a day, staying for 24 hours for calves use. Water was assessment immediately after water place (T0), after 17 hours (T1) and after 24 hours (T2). At the covered place, water was changed twice a day, staying for 17 hours (first water change) and for 7 hours (second water change) for calves use. Water was assessment immediately after water place of first water change (T0), after 17 hours (T1), immediately after water place of second water change (T0) and after 7 hours (T1). In rain season were analyzed three water sample with five repetitions each one. In dry season were analyzed three water sample (first and second with five repetitions and third with three repetitions). Water chlorination decreases the MPN of the enterococcus and E. coli and number of mesophilic microorganisms in all chlorination water samples. The best management to calves drinking water in dairy farm to guarantee water’s quality is the management at covered place, with chlorination (5,0 mg.L-1) and three time water change a day. / Mestre

Made available in DSpace on 2014-06-11T19:27:17Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-02-26Bitstream added on 2014-06-13T20:35:34Z : No. of bitstreams: 1 pinto_fr_me_jabo.pdf: 471521 bytes, checksum: 29f86a542fac384caf6026a29762bf8a (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Realizou-se o presente estudo objetivando-se conhecer a dinâmica da contaminação fecal e uso do cloro na desinfecção da água oferecida a bezerras em propriedade leiteira, pela determinação do número mais provável - NMP de enterococos e Escherichia coli, do número de microrganismos mesófilos, concentração de cloro, pH e temperatura. O manejo das bezerras era realizado em locais coberto e não coberto. Cada manejo utilizou dez bebedouros: cinco com água não clorada e cinco com clorada. No local não coberto a água sofria uma troca diária, estando 24 horas à disposição das bezerras, e era amostrada após sua colocação (T0), após 17 horas (T1) e 24 horas (T2). No local coberto ocorriam duas trocas diárias da água, estando 17 horas, na 1ª troca e 7 horas na 2ª troca à disposição das bezerras e as colheitas eram feitas após a colocação da água na 1ª troca (T0), após 17 horas (T1), após a colocação na 2ª troca (T0) e após 7 horas (T1). Na estação de chuva realizaram-se três amostragens com cinco repetições cada, na seca, três amostragens, as duas primeiras com cinco repetições e a última com três. A cloração reduziu significativamente os NMP de enterococos e E. coli e os números de microrganismos mesófilos em todas amostras de águas cloradas. O melhor manejo da água de consumo das bezerras foi em local coberto, com cloração (5,0 mg.L-1) e troca da água três vezes ao dia. / The objective of the study was to evaluate fecal contamination dynamic and use of chlorine on the disinfection of the offered water for calves in a dairy farm, through the most probably number determination (MPN) of enterococcus, Escherichia coli and determination of the mesophilic microorganisms, chlorine demand, pH and temperature. The calves management was at no covered and covered place. Ten watering though, five with chlorinated water and five with no chlorinated water were used in each one of the managements. At the no covered place, water was changed once a day, staying for 24 hours for calves use. Water was assessment immediately after water place (T0), after 17 hours (T1) and after 24 hours (T2). At the covered place, water was changed twice a day, staying for 17 hours (first water change) and for 7 hours (second water change) for calves use. Water was assessment immediately after water place of first water change (T0), after 17 hours (T1), immediately after water place of second water change (T0) and after 7 hours (T1). In rain season were analyzed three water sample with five repetitions each one. In dry season were analyzed three water sample (first and second with five repetitions and third with three repetitions). Water chlorination decreases the MPN of the enterococcus and E. coli and number of mesophilic microorganisms in all chlorination water samples. The best management to calves drinking water in dairy farm to guarantee water s quality is the management at covered place, with chlorination (5,0 mg.L-1) and three time water change a day.

No description available.

Les intégrons sont des plateformes génétiques bactériennes de capture et d'expression de gènes. Les intégrons cliniques sont les principaux responsables de la forte augmentation récente des bactéries multirésistantes aux antibiotiques. Cependant, dans l’environnement, ils ne représentent qu’une part minime de l’importante diversité des intégrons. Ainsi, les objectifs de cette thèse étaient (i) d’évaluer l’étendue de la diversité des intégrons dans l’environnement, (ii) de comprendre les phénomènes responsables de la structuration du pool d’intégrons dans le compartiment sédimentaire d’un milieu estuarien anthropisé et (iii) de rechercher l’existence potentielle d’intégrons indicateurs du niveau de contamination chimique.Le suivi des intégrons de classes 1, 2 et 3 et des populations d’E. coli dans des sédiments du bassin versant de la Risle impactés par des sources de contamination fécale bien caractérisées ont montré qu’en étiage, les souches d’E. coli d’origine humaine se disséminaient sur de courtes distances. Les intégrons de classe 1 se disséminent sur des distances un peu plus importantes et se maintiennent dans les 12 premiers centimètres du compartiment sédimentaire au moins.Une méthode a été développée permettant, pour la première fois, l’analyse de la diversité des intégrons via séquençage haut-débit. L’application de cette méthode sur une carotte sédimentaire de 4,8 m de profondeur prélevée dans l’estuaire fluvial de la Seine a permis de mettre en évidence plusieurs milliers de classes d’intégrons dont de nombreuses intégrases encore jamais répertoriées. La diversité des intégrons chute fortement avec la profondeur. Les intégrons de classe 1, majoritaires dans les sédiments de surface, ont une abondance qui chute fortement avec la profondeur cependant ils répondent plutôt positivement à la contamination chimique renforçant l’idée de leur utilisation comme proxy de pollutions anthropiques récentes. Trois classes d’intégrons dominent dans la vase consolidée représentant 38% des séquences obtenues dans la carotte sédimentaire mais répondant plutôt négativement à la contamination chimique. Enfin, la structure du pool d’intégrons est fortement corrélée à celle de la communauté bactérienne mais semble en partie indépendante de la communauté bactérienne dans deux des fractions sédimentaires profondes avec la dominance d’une nouvelle classe d’intégrons qui semble sélectionnée par les HAP. / Integrons are bacterial genetic platforms allowing acquisition and expression of genes. Clinical integrons play a major role in the strong increase of antibiotic multi-resistant bacteria recently observed. However, in the environment, they represent only a tiny fraction of the large integron diversity. Therefore, the aims of this thesis were (i) estimating the extent of the integron diversity in the environment, (ii) understanding phenomena responsible for integron pool structure in anthropized estuarine sediments and (iii) looking for integrons potentially proxy of chemical pollution level. The research of class 1, 2 and 3 integrons and the analysis of E. coli populations in sediments from the Risle drainage basin impacted by well-characterized fecal contamination sources show that E. coli strains with human origins were spread on short distances during low water level periods. However, class 1 integrons are spread on slightly longer distances and remain present in the 12 first centimeters of sediments at least. A methodology was developed allowing, for the first time, the analysis of integron diversity by high-throughput sequencing. In this way, the analysis of a 4.8 meter core sediment from the fluvial Seine estuary highlighted several thousands integron classes including many new integrases absent from data bases. Integron diversity decreases along with depth. Class 1 integrons are the majority integrons in surface sediments but their abundance strongly decreases in deep sediments. Class 1 integron abundance rather responds positively to chemical pollutions accentuating the idea that class 1 integrons could be used as proxy of recent anthropogenic pollutions. In the sediment core, three integron classes outshine the whole dataset: they represent 38% of all the sequences from the sediment core. However, abundances of these three majority integron classes rather respond negatively to chemical pollution levels. Integron pool structure is highly correlated to bacterial community diversity but seems to be partially independent to bacterial community diversity within two deep fractions from the sediment core: in these two sediment fractions, a new integron class outshines the rest of integron classes and seems to be specific to these two sediment fractions. Furthermore, this new integron class seems to be selected by PAH.

This study assessed the chemical substances that can be used to investigate fecal contamination of surface waters and how they can be used to indicate and trace fecal contamination in oligotrophic rivers of Northern Sweden. It was found that, from previous studies, several chemicals can be used to trace fecal contamination of surface water, and these include pharmaceuticals, personal care products, sterols, stanols and bile acids. Pharmaceuticals have been successfully used to indicate fecal contamination in many tropical countries and some countries in the cold regions and thus can also be applied to oligotrophic rivers. Sterols, stanols and bile acids make it possible to accurately indicate and trace the different sources of fecal contamination and can also be used to distinguish between the different organisms from which those sterols and bile acids emanate. For these groups of chemicals analytical methods such as chromatography and mass spectrometry are used to decipher the different chemicals in the test samples of water or sediment. Overall, these methods can be used concurrently but the sterols and bile acids have more specificity compared to the pharmaceuticals and personal care products / <p>2021-07-06</p>