The stable isotopes of the conservative element boron, 11B and 1°B, have been employed as co- migrating isotopic tracers to determine the origin of nitrate observed in groundwater from a large capacity (2500 gpm) irrigation well in the Avra Valley of southeastern Arizona. The isotopic ratios of the conservative element, boron, provided an identifying signature for various nitrate rich source waters. Additional chemical parameters were also examined to corroborate the isotopic indications. Findings of this investigation indicate that most of the nitrate observed in groundwater from well CMID 18 at the beginning of the 1993 irrigation season was due to municipal wastewater contamination. As the irrigation season progressed, an increasing proportion of nitrate was contributed by irrigation return flow from neighboring agricultural fields.

An experimental study of the low lying excited states of C¹¹ has been made using the B¹⁰(d ,nɣ )C¹¹ reaction at a deuteron bombarding energy of 0.8 Mev. Measurements were made of the n- ɣangular correlations of the ground state gamma transitions from the 6.49 and 4.32 Mev levels, and of the gamma ray branching ratios of the 6.49, 4.81 and 4.32 Mev levels. The apparatus used for the measurements was a combination of a NaI(T1) gamma ray spectrometer and an improved fast neutron time-of-flight spectrometer, developed by the author. Theoretical analysis of the n-ɣ angular correlations showed that the 6.49 Mev and 4.32 Mev levels are formed by the capture of p½ protons This restricts the Jπ values of these levels to (5/2)¯ or (7/2)¯. The parities of the states observed in this experiment are all known to be negative from the high energy stripping data of Cerineo and Maslin et al. A comparison of the experimental branching ratios with the theoretical branching ratios predicted by the intermediate coupling shell model is consistent with the following spin and parity assignments in C¹¹ : g.s. (3/2)¯, 2.00 Mev (1/2)¯, 4.32 Mev (5/2)¯, 4.81 Mev (3/2*)¯ and 6.49 Mev (7/2)¯. These assignments are in agreement with other recent results. The correspondence of these levels in C¹¹ with those of B¹¹ is consistent with the hypothesis of the charge independence of nuclear forces. The experimental results agree in some cases and disagree in others with the intermediate coupling shell model calculations of Kurath. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

This paper discusses the development of a microprocessor-based instrument to measure boron concentration in the cooling water of a pressurized water reactor. The technique used to develop the boronimeter is neutron transmission entailing the use of a neutron source and a bank of detectors to measure the absorbed neutrons in a sample of borated water. A unique feature of the boronimeter is the inclusion of a servo-operated absorber sleeve which is automatically positioned to compensate for changes in boron concentration. The sleeve is positioned to keep the count rate constant and the position of the sleeve is then used to determine the concentration of the sample. The null operation feature makes the boronimeter particularly adaptable to on-line operations owing to the improved counting statistics. Tests completed on the boronimeter demonstrate its usefulness for accurate, rapid analysis of boron concentration. The system was calibrated over the concentration range 0-2500 ppm boron. At a concentration of 1000 ppm the standard deviation was ± 2% for an analysis time of < 4 minutes. / Master of Science

The eastern margin of the Proterozoic Athabasca Basin in northern Saskatchewan is host to several of the highest-grade unconformity-related (U/C-related) uranium deposits in the world. Many researchers agree that uranium deposition occurred due to oxidized basinal brines transporting uranium mixing with reducing fluids or interacting with reduced rock causing uranium to precipitate, although the source of the uranium is still an unresolved and highly debated subject. Boron isotopic signatures, preserved in refractory minerals such as tourmaline, can aid in determining the source of fluids and P-T conditions during crystallization whereas lithium isotopic fractionation is indicative of weathering, hydrothermal alteration, and/or igneous and metamorphic processes. For this study a suite of fresh to strongly altered basement samples were selected from multiple sites below the eastern Athabasca Basin to measure the bulk delta7Li, delta11B and Pb-Pb isotopic signatures. Kinetic modelling of the Li and B isotopic systems suggest that both systems are slightly conservative of their original fluid reservoir, and by calculating the Damkohler numbers (ND) it is predicted that delta11B will be more indicative of the fluid source whereas lithium isotopes will equilibrate over shorter distance. However, both isotopic systems will fractionate with large concentration changes. Significant variations were observed for both delta7Li and delta11B, delta7Li values ranged from 0 to 14 ‰, the range in delta7Li was interpreted to be representative of both partial melting of metasediments to form granitic pegmatites and hydrothermal fluids. In comparison the range for delta11B was much larger from -16 to +17‰, within the dataset there appeared to be regional isotopic differences but unfortunately this dataset was too small to determine regional isotopic patterns. For each region the delta11B for the pegmatites was often heavier than the metasedimentary samples suggesting a metasedimentary source for the granitic pegmatites. Elevated U concentrations and decreasing 207Pb/206Pb ratios in both altered and unaltered samples suggest radiogenic Pb and U are present both in the basement and in fluids transporting U through the basement. Partial digestion 207Pb/206Pb ratios range from the common 207Pb/206Pb ratios of 0.7 to radiogenic 207Pb/206Pb ratios of 0.1. The radiogenic 207Pb/206Pb are indicative of either resetting of residual material during fluid migration or radiogenic fluids sources interacting with the rocks of this study.

The effects of boron supplementation on blood and urinary minerals were studied in 17 female college athletes and 11 sedentary college control subjects. The subjects were similar in age (19.8 ± 1.4 and 20.3 ± 1.1 years for athletes and sedentary groups, respectively) and weight (61.8 ± 9.1 and 59.6 ± 10.5 kgs for athletes and sedentary groups, respectively). The athletic subjects had lower percent body fat averages (20.6 ± 5.6 and 25.8 ± 6.5 %, respectively, (p < 0.05)) and higher aerobic capacities (2.9 ± 0.5 and 2.1 ± 0.4 L O₂*min₋₁, respectively, (p < 0.05) than sedentary controls. No differences in dietary intake were observed. Serum phosphorus levels were lower in boron supplemented subjects than in subjects receiving placebos (p < 0.05) and were lower during final analysis than during baseline analysis. A group-supplement interaction was noted with serum phosphorus also (p < 0.05). In the sedentary group, boron supplementation lowered serum phosphorus and placebo supplementation elevated serum phosphorus. In the athletic group, no changes in serum phosphorus were observed due to supplementation. Serum magnesium was greatest in the sedentary controls supplemented with boron and increased with time in all subjects (p < 0.05). Again, a group-supplement interaction was observed with serum magnesium; exercise in boron supplemented subjects lowered serum magnesium (p < 0.05). In all subjects, calcium excretion increased over time (p < 0.05) and in boron supplemented subjects boron excretion increased over time (p < 0.05). In conclusion, boron supplementation affected serum phosphorus and magnesium and the excretion of boron in the urine. The significance of these findings in relation to overall mineral status, bone mineral density, and exercise in college female athletes needs further investigation. It is possible that increasing the intake of foods high in boron may be found to be beneficial in the treatment and/or prevention of metabolic bone disorders such as those related to excessive exercise. / Ph. D.

Subduction zones, such as the Andean convergent margin, are the sites at which new continental crust is generated, and where subducting material is either recycled to the crust via arc magmatism or transferred to the deep mantle. The composition of arc magmas and associated new continental crust reflects variable contributions from mantle, crustal and subducted reservoirs. Insights into crustal growth and recycling processes in the southern Central Andes, specifically in the Pampean flat-slab segment, have been gained by utilising a range of petrological, geochronological and geochemical techniques. These techniques have been applied to a suite of Late Cretaceous (~73 Ma) to Late Miocene (~6 Ma) intrusive (granitoids) and extrusive (basalts to rhyolites) arc rocks collected from an east - west transect across the Andean Cordillera. The oxygen and hafnium isotopic composition of the accessory mineral zircon allows mantle-derived melts contaminated with older, upper continental crustal to be identified. Boron isotopic compositions of melt inclusions, combined with concentrations of certain incompatible trace elements, can be used to assess the source and influence of fluids derived from subducting material on the melt source region. The southern Central Andes provides a particularly interesting area to study these processes as the thickness of the continental crust has increased significantly over the course of the Cenozoic (from ~35 km to >50 km) and the angle of the subducting Nazca plate has shallowed since ~18 Ma, causing the position of the volcanic arc to migrate to the east. In order to unravel the complexities involved with constraining the contributions to arc magmas at an active continental margin, a range of geochronological, geochemical, and geothermobarometric techniques, including high resolution, micro-analysis of mineral phases and melt inclusions, have been applied. High resolution, U-Pb dating of magmatic zircon has improved regional stratigraphy in the Pampean flat-slab segment (between ~29 and 32 °S) and provided an accurate temporal constraint for geochemical and geothermobarometric data. The results of in-situ O and Lu-Hf isotope analysis of zircon show both distinct temporal and spatial variations across the Andean arc. The observed isotopic variability is attributed to variable contamination of mantle-derived melts with distinct Andean basement terranes, which vary east – west in composition and age. ‘Mantle-like’ δ18O(zircon) values, juvenile initial ƐHf(zircon) values and a lack of inherited, xenocrystic zircon cores, suggests the Late Cretaceous (~73 Ma) to Eocene (~39 Ma) plutons located in the Principal Cordillera of Chile, experienced very little interaction with the upper continental crust. Amphibole – plagioclase geothermobarometry indicates these calc-alkaline granitoids, which form extensive north – south trending belts, were emplaced at shallow depths in the crust (~4 – 5 km). Therefore the Late Cretaceous to Late Eocene is interpreted as a period of significant upper crustal growth. The isotopic variability in the Late Oligocene (~26 Ma) to Late Miocene (~6 Ma) arc magmatic rocks demonstrates that during thickening of the continental crust and migration of the Andean arc to the east, arc magmas assimilated Late Paleozoic to Early Mesozoic basement. In addition, arc magmas erupted/emplaced in the Argentinean Precordillera (i.e. farthest east from the trench) assimilated a Grenville-aged (~ 1330 – 1030 Ma) basement. The youngest arc magmas (~6 Ma) erupted in the Frontal Cordillera also show evidence for the assimilation of this ancient basement terrane, potentially signalling under-thrusting beneath the Frontal Cordillera. Overall, the later part of the Cenozoic represents a period of crustal reworking. Boron concentrations and isotope ratios measured in pyroxene hosted melt inclusions and for the first time in zircon hosted melt inclusions, are higher than the values expected for the mantle wedge and show significant variations with time. The source of the Paleocene (~61 Ma) arc magmas were influenced by fluids primarily derived from altered oceanic crust. Lower δ11B values and boron concentrations obtained for Oligocene (25 – 23 Ma) arc magmatic rocks reflects a diminished influence of slab-derived fluids reflecting a greater depth to the top of the slab. Fluids derived from serpentinite influenced the source of the arc magmas after ~19.5 Ma. This has been linked with the intersection of the Juan Fernández Ridge, a volcanic seamount chain associated with hydrated and serpentinised oceanic lithosphere.

M.Sc. / The origin of a wine plays a key role in establishing the quality and the price the consumer is prepared to pay. Fingerprinting techniques based on multi-element data combined with multivariate statistical analysis as well as isotope ratio data for certain elements such as boron (11B/10B) and strontium (87Sr/86Sr) are being developed and have been used for provenance determination of wine with varying degrees of success. The aim of this study was to develop a method to determine boron isotope ratios (11B/10B) with the required precision using ICP-MS (inductively coupled plasma mass spectrometry) in soil and wine samples and applying this method to establish the origin of South African wines. Analytical difficulties such as the boron memory effect, dead time, mass bias drift and matrix effects were investigated. Although the memory effect, dead time and mass bias drift were satisfactorily resolved, it was not possible to determine what the cause of all the observed matrix effects was during this study. The method was used to categorise wines from the Robertson, Swartland and Stellenbosch regions and an attempt was made to link the measured boron isotope ratios with that obtained from the corresponding provenance soils. The 11B/10B isotope ratios for the wine samples (Robertson: 4.202 ± 0.014, Swartland: 4.173 ± 0.013 and Stellenbosch: 4.174 ± 0.028) were, however, higher than the ratios obtained for the soil samples (Robertson: 4.108 ± 0.020, Swartland: 4.070 ± 0.023 and Stellenbosch: 4.124 ± 0.039). It was possible to distinguish, using the boron isotope ratios (wine and soil samples), between the Robertson area (Breede River region) and the Swartland area (Coastal region). The wine and soil 11B/10B isotope ratios obtained for the Stellenbosch area (Coastal region) overlapped with the 11B/10B isotope ratios of the Robertson and Swartland regions making it impossible to differentiate it from these two regions.

Investigating past changes in Earth's climate can provide useful information for assessing future climate change scenarios. Planktic foraminifera preserved in marine sediment are commonly used as a tool to reconstruct past environmental change. Here I present a combination of modern census and multinet data from the North Pacific, a new compilation of global census data, a new global calibration for Mg/Ca ratios in Neogloboquadrina pachyderma, and foraminifera assemblage, trace element, and boron isotope data from the North Pacific spanning the last deglaciation. New modern census data from the North Pacific shows that two key sub-polar proxy carrying species, N. pachyderma and Globigerina bulloides, predominantly live between 0-50 m in the water column. Global planktic foraminifera diversity is observed to be driven primarily by sea surface temperature, with upwelling and ocean productivity providing key secondary roles. In the North Pacific, a preservation bias of N. pachyderma over G. bulloides is observed when comparing multinet and core-top samples, highlighting the importance of tracking dissolution during downcore studies. To improve the use of Mg/Ca ratios in N. pachyderma downcore, I produced a new global calibration with a temperature sensitivity of 6 % per °C. This calibration was combined with boron isotope and Mg/Ca data from sediment core MD02-2489 to investigate changes in North Pacific circulation, productivity, and CO₂ during the last deglaciation. Two intervals of high surface CO₂ were observed, the first during Heinrich Stadial 1, where deep ventilation mixed CO₂ and nutrients throughout the water column. The second occurred during the Bølling-Allerød, where stratification pooled nutrients and CO₂ in surface waters, leading to enhanced productivity and CO₂ outgassing. Overall, this thesis improves the use of planktic foraminifera as tools for investigating past climate change and highlights the role of the North Pacific in deglacial CO₂ release.

<p>Coal fired power plants are ubiquitous in the United States and most developed countries around the world, providing affordable electricity to consumers. In the US, approximately six hundred power plants generate 136 million tons of Coal Combustion Residuals (CCRs) annually, encompassing fly ash, bottom ash, and flue gas desulfurization materials. The range and blends of CCRs varies substantially across coal-fired plants and depends on a unique set of circumstances for each plant and coal source. Current U.S. regulations mandate the installation of advanced capture technologies to reduce atmospheric pollution, but do not address the transfer and storage, or the potential impacts to water resources. Thus improved air quality is traded for significant enrichments of contaminants in the solid waste and effluent discharged from power plants. </p><p>This work examines the geochemical and isotopic characteristics of CCRs, as well as potential environmental impacts from CCRs. This investigation looks at several different aspects of CCR and environmental interactions from 1) the immediate impacts of the 2008 TVA coal ash spill in Kingston, TN, 2) the long-term (18-month) exposure of the spilled ash in the Emory and Clinch rivers, 3) impacts on waterways in North Carolina that receive CCR effluent from coal fired power plants, and 4) examination of boron and strontium isotopes of CCRs from leaching experiments and their application as tracers in the environment of the TVA spill and NC waterways. These investigations have illuminated several conclusions, including contact of surface water with CCRs leach high concentrations of leachable CCR contaminants, such as As, Se, B, Sr, Mo, and V in the surface waters; the dilution effect is critical in determining the concentration of contaminants from the CCRs in surface water (both at the spill and in waterways receiving CCR effluent); recycling of trace elements (such as As) through adsorption/desorption can impact water quality; and elevated boron and strontium concentrations, in addition to their isotopes, can trace CCR effluent in the environment. Combining the geochemical behavior and isotopic characteristics provides a novel tool for the identification CCR effluents in the environment.</p> / Dissertation

M.Sc. / The 11B/10B stable isotope ratio in wine- and provenance soil samples of four South African wine regions was determined by means of quadrupole inductively coupled plasma mass spectrometry (ICP-MS). The data obtained was combined with multi-element results for the same samples. Discriminant analysis and ANOVA statistics were utilized to create a footprint of wines compared to their provenance soil. The results showed that the stable boron isotope ratio was a distinguishable characteristic in wine and soil samples for the Stellenbosch, Robertson, Swartland, and Walker Bay wine regions. The potential improvement of precision and accuracy was investigated specifically for ICP-QMS (quadrupole mass spectrometry) analysis of boron isotope ratios. Sample preparation methods for the matrices used in this work were developed and applied. The influence of the matrix components was investigated. Ion exchange separation procedures were developed for the separation of total B from the wine and soil matrices. Results were treated mathematically to minimize mass bias effects. It was found that combined matrix effects and TDS (total dissolved solids) deposition did have a pronounced effect on the 11B/10B isotope ratios of the samples. The possibility of boron isotope fractionation was investigated in vine plants. Hydroponic experiments were set up with test plants of two cultivars. A 10B enriched nutrient solution or growth solution with natural 11B/10B ratio was supplied to the plants during alternating periods of 5 weeks each. New growth leaves were harvested once every week during each of these time periods. All samples were carefully prepared and analyzed to determine the relationship of the 11B/10B ratio in the leaves compared to that of the supplied nutrient solution. It was observed that the 11B/10B isotope ratio of the growth solution had an influence on the 11B/10B stable isotope ratio in new growth leaves of vine plants.