Thesis (Ph.D.) - University of Glasgow, 2002. / Ph.D. thesis submitted to Environmental, Agricultural and Analytical Chemistry, Chemistry Department, University of Glasgow, 2002. Includes bibliographical references. Print version also available.

Thesis (M.Env.Sci.)--Memorial University of Newfoundland, 1997. / Bibliography: leaves 55-58.

Thesis (Ph. D.)--University of California, Santa Cruz, 1996. / Typescript. Includes bibliographical references (leaves 149-150).

Thesis (doctoral)--Technische Universiteit Delft, 2001. / Includes bibliographical references (p. 139-150).

Thesis (Ph. D.)--Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1980. / Photocopy of typescript. Bibliography: p. 225-239.

Thesis (Ph. D.)--Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1976. / Vita. "Joint Program in Oceanography, Massachusetts Institute of Technology - Woods Hole Oceanographic Institution, and Department of Earth and Planetary Sciences, Massachusetts Institute of Technology, April, 1976." "June, 1976."--Cover. Includes bibliographical references.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Sciences, 1981. / Supervised by John M. Edmond. Vita. Includes bibliographical references (leaves 225-239).

abstract: The present understanding of the formation and evolution of the earliest bodies in the Solar System is based in large part on geochemical and isotopic evidences contained within meteorites. The differentiated meteorites (meteorites originating from bodies that have experienced partial to complete melting) are particularly useful for deciphering magmatic processes occurring in the early Solar System. A rare group of differentiated meteorites, the angrites, are uniquely suited for such work. The angrites have ancient crystallization ages, lack secondary processing, and have been minimally affected by shock metamorphism, thus allowing them to retain their initial geochemical and isotopic characteristics at the time of formation. The scarcity of angrite samples made it difficult to conduct comprehensive investigations into the formation history of this unique meteorite group. However, a dramatic increase in the number of angrites recovered in recent years presents the opportunity to expand our understanding of their petrogenesis, as well as further refine our knowledge of the initial isotopic abundances in the early Solar System as recorded by their isotopic systematics. Using a combination of geochemical tools (radiogenic isotope chronometers and trace element chemistry), I have investigated the petrogenetic history of a group of four angrites that sample a range of formation conditions (cooling histories) and crystallization ages. Through isotope ratio measurements, I have examined a comprehensive set of long- and short-lived radiogenic isotope systems (26Al-26Mg, 87Rb-87Sr, 146Sm-142Nd, 147Sm-143Nd, and 176Lu-176Hf) within these four angrites. The results of these measurements provide information regarding crystallization ages, as well as revised estimates for the initial isotopic abundances of several key elements in the early Solar System. The determination of trace element concentrations in individual mineral phases, as well as bulk rock samples, provides important constraints on magmatic processes occurring on the angrite parent body. The measured trace element abundances are used to estimate the composition of the parent melts of individual angrites, examine crystallization conditions, and investigate possible geochemical affinities between various angrites. The new geochemical and isotopic measurements presented here significantly expand our understanding of the geochemical conditions found on the angrite parent body and the environment in which these meteorites formed. / Dissertation/Thesis / Ph.D. Geological Sciences 2012

No description available.

The accumulation of metal contaminants in the human environment has received a great deal of attention during the last several years as it has become apparent that their presence, in excess, represents a threat to human health. Biochemical assays to determine concentrations of metals in the human body have used such tissues as blood, bone, hair, nails and, more recently, teeth. The present study attempts to provide further evidence for the use of deciduous teeth as indicators of human exposure to concentrations of lead, copper and zinc as a result of ore smelting operations in Kamloops and Trail, British Columbia. Kamloops represents an area of minimum exposure to smelter operations in contrast to Trail where a lead/zinc smelter has been operating for many years. Concentrations of lead, copper and zinc in deciduous teeth from geographically-stable Kamloops children, aged 5 years to 12 years, were compared to concentrations found in a similar population of geographically-stable Trail children. Whole teeth were digested in nitric and perchloric acids and trace element concentrations were determined using inductively coupled plasma emission spectroscopy. Mean lead and zinc concentrations for Kamloops and Trail teeth, respectively, were: 31.6 ± 7.33 ppm and 48.2. ± 11.5 ppm for lead (p < 0.05) and 103.4 ± 23.6 ppm and 111.9 ± 15.4 ppm for zinc. Copper was undetectable at < 1 ppm in all teeth. Locally-grown foods from each area and foods grown elsewhere were also analyzed for lead, copper and zinc in an effort to establish the possible contribution of these elements from local food resources in Kamloops and Trail. Twenty-four hour diet composites were collected and analyzed for copper and zinc by atomic absorption spectroscopy. Mean copper and zinc concentrations for foods grown in Kamloops and Trail, respectively, were: 1.5 ± 0.4 ppm and 1.6 ± 0.9 ppm for copper and 3. 2 ± 1.3 ppm and 3.1 ± 0.9 ppm for zinc. Mean copper and zinc concentrations for non-locally grown foods collected from Kamloops and Trail, respectively, were: 1.1 ± 0.2 ppm and 1.6 ± 0.8 ppm for copper and 5.8 ± 1.9 ppm and 6.5 ± 0.3 ppm for zinc. Lead was determined by plasma emission spectroscopy, and was found to be undetectable at < 1 ppm in all food samples. To assess the extent of maximal consumption of locally-grown foods, selected home gardeners in the Brocklehurst district of Kamloops and the Genelle district of Trail were interviewed. Seasonal consumption and home food preservation practices were determined. In addition, 24-hour diet recalls were obtained from 177 Brocklehurst district children in September and April, 1977-78 to determine "typical" eating patterns of these children. . The amount of locally-grown foods consumed was dependent mainly on season of the year; however, choice of food by the children on the whole did not differ from fall to spring. The recalls also indicated that males consumed more food than females, particularly protein. Meals, especially breakfast, were frequently missed, and non-nutritious snacks were common to the diets of many of the children. Results from this study indicated that, although deciduous tooth lead concentrations were significantly (p<0.05) higher in Trail than in Kamloops, samples of locally-grown foods obtained in 1978 from these two communities were not excessively high in lead, zinc or copper. In fact, these elements in foods compared well to concentrations reported in other areas of North America. It would appear, then, that the higher concentrations of lead in Trail teeth are a result of increased intake from other environmental sources. Analyses of food consumption patterns of gardening families revealed that local foods comprised an important part of the diet. Measures should be taken to ensure the continued safety of foods in areas where mineral mining and smelting occur. / Land and Food Systems, Faculty of / Graduate