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Item Impact of increasing NaCl levels in livestock drinking water on the intake and utilization of low-quality forages by beef cattle(Montana State University - Bozeman, College of Agriculture, 2022) Nack, Makae Frances; Chairperson, Graduate Committee: Timothy DelCurto; This is a manuscript style paper that includes co-authored chapters.Water is one of the most important nutrients for livestock production (Petersen et al., 2015) but its quality is often overlooked in western range settings. The western United States and more specifically, Montana, are prone to variable precipitation and droughts, reducing the quantity and quality of livestock drinking water as well as limited forage quality/quantity. Dormant season grazing of rangeland forages often involves utilizing self-fed, salt limited supplements to meet cattle nutrition requirements and better utilize forage. Self-fed supplements commonly add salt as an intake limiter because it is effective, cheap and necessary in beef cattle diets (Cardon et al., 1951). The objective of this study was to evaluate the impacts of increasing NaCl levels in water on low quality forage intake, digestibility, and rumen fermentation of cattle consuming low quality forage. Eight, ruminally-cannulated, Angus crossbred cows were individually stalled and used in two 4 x 4 Latin squares design. One square was hand fed a non-salt supplement; the second square was fed a salt limiting supplement. Two cows (one from each square) were assigned to one of four water treatments per period: 1) control, no added NaCl; 2) 1000 mg NaCl/L; 3) 2000 mg NaCl/L; and 4) 3000 mg NaCl/L. A 14-day adaption period allowed cattle to acclimate to the water; followed by a 6-day total collection period. Rumen fluid samples were collected on day 22 at hours 0, 4, 8, 12, 18 and 24; and on day 23 a total rumen evacuation was conducted to determine total rumen volume and collect rumen content samples. Increasing levels of NaCl did not influence intake in either study (P > or = 0.36). Rumen pH was influenced by water NaCl in study 1 (P = 0.01), however, post hoc analysis revealed no differences. Volatile fatty acids in both studies were not affected by NaCl in either study (P > or = 0.39). Our results suggest the NaCl levels in our study may have little influence on intake, rumen fermentation and liquid kinetics suggesting NaCl levels up to 3,000 are safe for cattle.Item Investigating arsenic-microbiome interactions in the gut using murine models(Montana State University - Bozeman, College of Letters & Science, 2019) Coryell, Michael Philip; Chairperson, Graduate Committee: Seth Walk; B. A. Roggenbeck and Seth T. Walk were co-authors of the article, 'The human gut microbiome's influence on arsenic toxicity' submitted to the journal 'Current pharmacology reports' which is contained within this thesis.; M. McAlpine, N.V. Pinkham, T.R. McDermott and Seth T. Walk were co-authors of the article, 'The gut microbiome is required for full protection against acute arsenic toxicity in mouse models' in the journal 'Nature communications' which is contained within this thesis.; M. Yoshinaga, T.R. McDermott and Seth T. Walk were co-authors of the article, 'Speciation of excreted arsenicals from germ free and conventional AS3MT knockout mice exposed to inorganic arsenate' which is contained within this thesis.Drinking water contamination with arsenic is a wide-spread public health concern, potentially affecting over 140 million people across at least 40 different countries. Current understanding of biological and behavioral factors influencing clinical outcomes is insufficient to explain the variation observed in arsenic-related disease prevalence and severity. The intestinal microbiome in humans is a dynamic and active ecosystem with demonstrated potential to mediate arsenic metabolism in vitro and distinct variability between individuals. This dissertation investigates arsenic-microbiome interactions, with a focus on determining how microbiome activity influences host-response and toxicity from arsenic exposures. Chapter 2 overviews common exposure routes, important metabolic pathways, and current evidence of arsenic-microbiome interactions in humans or experimental animal models. Chapter 3, the initial approach was to experimentally perturb the microbiome of common laboratory mice during arsenic exposure, measuring arsenic excretion in the stool and accumulation in host tissues. Arsenic sensitive gene-knockout mice were used to determine the microbiome's influence on subacute arsenic-induced mortality. Disrupting microbiome function--first by antibiotic treatment, then by deriving mice germ free--dramatically reduced survival times during severe arsenic exposures. Transplantation of human fecal communities into germ free mice effectively complemented the loss of function from microbiome disruption in these mice. Chapter 4 examines microbiome's impact on arsenic metabolism in germ free and conventional mice from this same arsenic-sensitive genetic background. These mice are deficient for the primary metabolic pathway involved in arsenic detoxification in both humans and mice, facilitating a more complete experimental isolation of microbiome and host metabolisms. This study provides evidence of microbiome-dependent changes in the elimination routes and metabolic transformation of ingested arsenic and provides a new experimental model for studying arsenic metabolism in the gut.Item Structural controls and chemical characterization of brecciation and uranium vanadium mineralization in the northern Bighorn Basin(Montana State University - Bozeman, College of Letters & Science, 2016) Moore-Nall, Anita Louise; Chairperson, Graduate Committee: David R. Lageson; Margaret Eggers, John Doyle, Myra Lefthand, Sara Young, Ada Bends, Anne Camper and CEHSC were co-authors of the article, 'Potential health risks from uranium in home well water: an investigation by the Apsaalooke (Crow) Tribal Research Group' in the journal 'GeoSciences' which is contained within this thesis.; Ranalda Tsosie was a co-author of the article, 'Ree data support oil with a Permian phosphoria formation source as a source of metals for U and V mineralization in the northern Bighorn Basin' submitted to the journal 'Minerals' which is contained within this thesis.The goals of this research were to determine if the mode of mineralization and the geology of two abandoned uranium and vanadium mining districts that border the Crow Reservation might be a source for contaminants in the Bighorn River and a source of elevated uranium in home water wells on the Reservation. Surface and spring waters of the Crow Reservation have always been greatly respected by the Crow people, valued as a source of life and health and relied upon for drinking water. Upon learning that the Bighorn River has an EPA 303d impaired water listing due to elevated lead and mercury and that mercury has been detected in the fish from rivers of the Crow Reservation this study was implemented. Watersheds from both mining districts contribute to the Bighorn River that flows through the Crow Reservation. Initial research used the National Uranium Resource Evaluation database to analyze available geochemistry for the study areas using GIS. The data showed elevated concentrations of lead in drainages related to the mining areas. The data also showed elevated uranium in many of the surface waters and wells that were tested as a part of the study on the Crow Reservation. The author attended meetings and presented results of the National Uranium Resource Evaluation data analyses to the Crow Environmental Health Steering Committee. Thus, both uranium and lead were added to the list of elements that were being tested in home water wells as part of a community based participatory research project addressing many issues of water quality on the Crow Reservation. Results from home wells tested on the reservation did show elevated uranium. Rock samples were collected in the study areas and geochemically analyzed. The results of the analyses support a Permian Phosphoria Formation oil source of metals in the two mining districts. Structural data support fracturing accompanied by tectonic hydrothermal brecciation as a process that introduced oil and brines from the Bighorn Basin into the deposits where the uranium vanadium deposits later formed.Item The welfare impacts of Engineers Without Borders in western Kenya(Montana State University - Bozeman, College of Agriculture, 2015) Donavin, Kirkwood Paul; Chairperson, Graduate Committee: Sarah JanzenThe undergraduate chapter of Engineers Without Borders at Montana State University (EWB-MSU) work towards improvement of student welfare by providing bore hole wells and composting latrines to primary schools in Khwisero, Kenya. These projects seek to improve the safety of drinking water at the school, increase school attendance and performance and decrease time spent collecting water in these communities. Data were collected from 776 households in Khwisero in order to measure the organization's impact. Instrumental variable methods are used to analyze EWB-MSU's impact on health outcomes, while fixed effect analysis is used to investigate the impact on education and time-use outcomes. No impact is detected on student health or education due to EWB-MSU projects but households surrounding EWB-MSU water projects spend almost one minute fewer, on average, traveling to their primary water source relative to other households.Item Groundwater nitrate transport and residence time in a vulnerable aquifer under dryland cereal production(Montana State University - Bozeman, College of Agriculture, 2013) Miller, Christine Ross; Chairperson, Graduate Committee: Stephanie A. Ewing; Stephanie A. Ewing, W. Adam Sigler, E. N. J. Brookshire, Clain A. Jones, Douglas Jackson-Smith and Gary S. Weissmann were co-authors of the article, 'Groundwater nitrate transport and residence time in a vulnerable aquifer under dryland cereal production' submitted to the journal 'Journal of geophysical research - biogeosciences' which is contained within this thesis.Selection of agricultural management practices to reduce nitrate leaching from soils can only be successful if both nitrate loading rates from soils to shallow aquifers and groundwater residence times are quantified. Elevated nitrate concentrations in shallow unconfined aquifers are commonly observed in agricultural areas as a result of increased N inputs. In the Judith River Watershed (JRW) in central Montana, USA, notably high nitrate concentrations in groundwater and stream water have exceeded the U.S. EPA drinking water standard of 10 mg L -1 for at least two decades. This large (24,400 ha) watershed drains immediately into the Missouri River, a tributary of the Mississippi River. Over an eleven month period in 2012, we measured groundwater and surface water nitrate concentrations across a hydrologically isolated strath terrace. We use the resulting data to constrain nitrate accumulation dynamics in the shallow aquifer. Nitrate is relatively conservative in this location, as it is high in groundwater (17.57 +/- 4.29 mg L -1; all groundwater samples pooled together), and remains high in streams and springs that drain the landform (15.67 +/- 9.45 mg L -1; all surface water and spring samples pooled together). We use a numerical model to simulate the character of nitrate accumulation in the aquifer as a whole, in order to evaluate how the entire period of cultivation has contributed to current nitrate concentrations, and begin to predict response times for effects of land use change. We consider the effect of groundwater residence time and travel time on nitrate loading using particle tracking in a three dimensional model aquifer. We find no correlation with nitrate concentrations in groundwater and emerging surface waters, and suggest approaches for improving both the geometry of the model and the selection of sites in future work. Overall, our results imply that groundwater residence times are several decades at most, suggesting that similar timeframes will be needed to reduce overall nitrate concentrations in groundwater and emergent streams to below drinking water standards. Preliminary evaluation of several management scenarios suggests that both increased fertilizer use efficiency and rotational strategies may be needed to prevent the loss of soil N to groundwater.Item Chromatographic, spectroscopic and microscopic analyses reveal the impact of iron oxides and electron shuttles on the degradation pathway of 2,4,6- trinitrotoluene (TNT) by a fermenting bacterium(Montana State University - Bozeman, College of Agriculture, 2003) Borch, Thomas; Chairperson, Graduate Committee: William P. Inskeep and Robin Gerlach (co-chair)Contamination of surface and subsurface environments with explosives such as 2,4,6-trinitrotoluene (TNT) is a worldwide problem. The fate and analysis of TNT were investigated in numerous artificially contaminated model systems. We developed a unique high performance liquid chromatography gradient elution method for the analysis of commonly observed TNT metabolites and EPA explosives. Column temperature was identified as the key parameter for optimal separation. Iron (hydr)oxides play an important role in the reduction, sorption and fate of TNT in soil and sediment. Consequently, characterization of the nature and properties of natural and synthetic Fe (hydr)oxides is important for determining reaction mechanisms and surface-associated chemical processes. This work thus summarizes the potential applicability of imaging and spectroscopic techniques for eliciting chemical and physical properties of iron (hydr)oxides. TNT is persistent in soils due to its low redox potential and sorption. Batch and column studies revealed some of the first results on TNT desorption behavior in two well-defined model soil systems. Biosurfactants were found to be the most promising technique for enhanced TNT desorption. Batch studies with a Cellulomonas sp. in the presence of ferrihydrite and the electron shuttle anthraquinone-2,6-disulfonate (AQDS) were conducted to reveal biotic and abiotic mechanisms contributing to the degradation of TNT. Strain ES6 was found to reduce TNT and ferrihydrite with enhanced reduction in the presence of AQDS. Ferrihydrite stimulated the formation of more reduced TNT metabolites such as 2,4-diamino-6-nitrotoluene. Interestingly, a completely different degradation pathway was observed in AQDS-amended iron-free cell suspensions, showing a rapid transformation of TNT to 2,4-dihydroxylamino-6-nitrotoluene, which transformed into unidentified polar products. The influence of iron phases (i.e. hematite, magnetite, and ferrihydrite) and secondary Fe mineral formation on the degradation of TNT was also evaluated. The initial reduction of TNT was fastest in the presence of hematite; however, the further reduction of hydroxylamino-dinitrotoluenes was fastest, in the presence of magnetite and ferrihydrite (no AQDS). The impact of AQDS was predominant in the presence of hematite resulting in the formation of 2,4,6-triaminotoluene. Ferrihydrite underwent reductive dissolution with the formation of secondary hematite. The enhanced TNT reduction in ferfihydrite-amended systems was therefore most likely due to redox-active Fe(II) rather than secondary Fe phases.Item The influence of distribution system infrastructure on bacterial regrowth(Montana State University - Bozeman, College of Engineering, 2001) Van Andel, KristinItem Kinetics of biofilm growth and substrate uptake in model drinking water systems(Montana State University - Bozeman, College of Engineering, 1998) Butterfield, Phillip WesleyItem Pathogens in model distribution system biofilms(Montana State University - Bozeman, College of Agriculture, 1996) Warnecke, Malcolm RobertItem Modeling chlorine concentrations in municipal water systems(Montana State University - Bozeman, College of Engineering, 1985) Murphy, Scott Brian
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