Univ., Diss., 2004--Marburg

No description available.

This study utilizes new geochemical analyses of fluids (formation water and gas) collected predominately from Devonian organic-rich shales and reservoir sandstones from the northern Appalachian Basin margin to investigate basin scale hydrologic processes, water-rock reactions, microbial activity, and natural gas generation. Elemental and isotopic composition of co-produced formation waters and natural gas show that the majority of methane in Devonian organic-rich shales and reservoir sandstones is thermogenic in origin with localized accumulations of microbial gas. Microbial methanogenesis appears to be primarily limited by redox buffered conditions favoring microbial sulfate reduction. Thermal maturity (bioavailability) of shale organic matter and the paucity of formation waters may also explain the lack of extensive microbial methane accumulations. Iodine and strontium isotopes, coupled to elemental chemistry demonstrate basin scale fluid flow and clay mineral diagenesis. Evidence for this is based on anomalously high ¹²⁹I/I values sourced from uranium deposits (fissiogenic production of ¹²⁹I) at the structural front of the Appalachian Basin. Radiogenic ⁸⁷Sr/⁸⁶Sr (up to 0.7220), and depleted boron and potassium concentrations support smectite clay diagenesis at temperatures greater than 120 °C. The development of fissiogenic ¹²⁹I as a tracer of basin scale fluid flow is a novel application of iodine isotopes provided that the sources of cosmogenic and anthropogenic ¹²⁹I are reasonably well constrained. The anomalously high ¹²⁹I/I in Appalachian Basin brines may be alternatively explained by microbial fractionation based on a correlation with decreasing δ¹³C-DIC values and decreasing sulfate concentrations in the range of sulfate reduction. These results demonstrate that the microbial fractionation of iodine isotopes may be possible and an important consideration when interpreting ¹²⁹I/I, regardless of the source of ¹²⁹I. Results from this study have important implications for understanding the controls on and origins of natural gas production in sedimentary basins; tectonically and topographically driven basin scale fluid flow, including diagenetically induced waterrock reactions and mineral ore deposition related to orogenesis; and an improvement of the use of iodine isotopes for understanding large scale fluid flow, and possibly its use as a tracer of organic matter diagenesis and the distribution of radionuclides in the environment.

Techn. Universiẗat, Diss., 2005--München.

Universiẗat, Diss., 1999--Dortmund. / Dateiformat: PDF.

Universiẗat, Diss., 2000--Dortmund. / Dateiformat: PDF.

The geology, hydrogeology, and groundwater geochemistry are described for an interface aquifer in Eastern Ontario exhibiting anomalously high proportions of iodine (I) as iodide (I-) and dissolved methane (CH4). The studied area is unique in that it shows a significant marine influence, attributed to the most recent Champlain Sea incursion 10 – 12 ka BP, which has implications for I and CH4 enrichment. I and CH4 in groundwater are found in high proportions in reducing fossil seawaters, which are typically observed in depressions in the bedrock surface that are overlain by thick layers of glaciomarine muds. I is released via microbial decomposition of marine phytoplankton into mud porewaters, where it is then leached to underlying groundwaters. 129I and 14C isotopic signatures of I and C compounds highlight the importance of allochthonous I and C sources in the Champlain Sea basin derived from glacial abrasion of the surrounding terrain and imported via glacial meltwater. CH4 is microbial in origin, with marine phytoplankton from the Champlain Sea incursion and ancient terrestrial organic matter from an Early Wisconsinian interstadial period (60 – 75 ka BP) as the dominant substrates. A thermogenic CH4 component was observed for areas underlain by the Billings shale unit. Both I and CH4 originate at least partially from the same marine phytoplankton source within the muds, demonstrate similar controls on enrichment, and have a Spearman’s rank coefficient of 0.62, indicating that the correlation between I and CH4 in groundwater in the studied area is significant.

No description available.

This thesis concerned with iodine status, sources in human body, and measurements especially here in Canada, where iodine status for the Canadian population is not well known. With the recent re-emergence of iodine deficiency among individuals in other industrial countries, understanding the main sources of iodine to the Canadian population is necessary to ensure fortification strategies are justified and effective. Uncertinaty has arisen to the importance of iodized salt recently, along with medical warnings to reduce salt consumbtion. This conflicts give rise to improve scientific research and hone thier methods with new applications. The research question here is that: Can we benefit from the existence of long-lived radioiodine-129 in the environment and explore its potential as a tracer? To answer this question, the study was divided into an introductory chapter contains a review about the topic, then three research chapters. The second chapter was devoted to study the possibility of extracting 129I from human urine. As for third chapter of the thesis, it was about refining a method that already established, and use it to extract 129I from breastmilk using combustion, then determine the radiological dose of 129I in infants’ thyroid. While the fourth chapter was devoted to investigate the main sources of 127I and 129I in the Canadian diet based on daily food consumption and modelling the urinary iodine concentration for adults and infants through the novel application of a well-established compartment model implemented in AMBER. The path of this thesis was crowned with a set of results, which are detailed in the end of each chapter as follow: 1- The advantage of accelerator mass spectrometry (AMS) helps to measure 129I in human urine for the first time. The result for 25 participants from Ottawa ranged from 3.3 x 106 atoms/L to 884 x 106 atoms/L with a median of 108.7 x 106 atoms/L, and the 129I/127I ratio ranged from 7.38 x 10-12 to 3.97 x 10-10 with a mean of 1.3 x 10-10. 2- The concentration of 127I and 129I in Ottawa urine samples were significantly correlated and generally similar to the 129I concentrations and 129I/127I ratios from environmental samples collected around Ottawa. 3- This correlation suggests that 129I could be a potential nutritional tracer of dietary iodine. 4- In chapter 3, the 129I in breastmilk ranged from 1.26x108 atoms/L to 6.64x108 atoms/L with a median of 2.10 x108 atoms/L, and the 129I/127I ratio ranged from 1.27x10-10 to 9.9x10-10 with a median of 2.13x10-10. 5- A correlation was also observed between 127I and 129I concentrations in breastmilk. 6- The isotopic ratios in breastmilk were similar to Canadian cow’s’ milk, indicating that the milk of both cows and humans is a reflection of the 129I concentration of their local environment and the food ingested. 7- Result from chapter 3 confirms that humans are exposed to the 129I from birth through their mother breastmilk, giving them an average dose of 1.10 x10-4 Bq/year and thyroid dose rate equal to 5.92 x10-10 Sv/year. 8- In fourth chapter, the daily milk consumption was measured for 78 mother-infants’ pairs, and ranged from 275 -1202 g/day, with a mean of 731 g/day. This value agrees well with global infant milk intake which estimated at 730g/day. 9- The daily iodine intake from breastmilk ranged from 11.2 µg/day to 476.2 µg/day with a median of 127.9 µg/day. 10- The urinary iodine concentrations were estimated without urine collection using iodine biokinetic model, giving a median urinary iodine concentration (n=78) at 304.7 µg/L. The result was compared to those measured by Health Canada (median= 398.7 µg/L), showing a moderate correlation (r= 0.496). 11- A further comparison of the results was made based on gender shows that the difference between UIC in male and female infants measured by Health Canada and those estimated by AMBER is non-significant. 12- Through AMBER software, the influence of seven common diets on UICs was assessed to determine which foods play an important role in ensuring iodine adequacy. We observed that the main source of iodine in a vegan diet is grain products providing up to 70%, while in remaining diets the main source of iodine was dairy products (50-69%) when they are consumed. 13- The contribution of iodized salt to all Canadian diets was ranked second, after dairy, unless the diet is vegan or ovo-vegetarian, where dairy is not consumed, iodized salt was ranked first. 14- Among 23 scenarios for seven different diets, the urinary iodine-129 concentrations ranged from 1.4 x10-7 to 3.3 x10-7 µg/L with a median of 3.1 x10-7 µg/L, and the isotopic 129I/127I ratio ranged from 1.1 x10-9 to 1.2 x10-8 with a median of 2.8 x10-9. 15- In contrast to stable iodine, the highest isotopic ratio was observed in vegan diet, while the lowest was observed in ketogenic diet. This suggests that grain products are the main contributor of 129I to humans. 16- Despite being the primary contributors of stable iodine (127I), salt and dairy show a lower contribution of 129I. Based on this we can qualitatively predict the source of iodine 127 using isotopic ratio 129I/127I. For example, in cases where the isotopic ratio was between 10-8 and 10-9, therefore, the main sources of iodine in this person may be from grains products, vegetables, and fruits; and in cases where the isotopic ratio was between 10-10 and 10-11, therefore, the main sources of iodine in this person may be from dairy products and some contribution from salt. This study has shown the capability of 129I to be used in biomedical fields. In this thesis 129I used as a nutritional tracer where it helps to detect the sources of stable iodine in human body based on isotopic ratio. The extraction method invented in Chapter 2 can be used to evaluate 129I exposure directly in the human body for those who live nearby nuclear fuel reprocessing plants. An additional application for this method can be in assessing 129I in human to investigate 131I uptake in the event of a nuclear emergency using 129I in urine as a proxy. Moreover, the extraction technique used Chapter 3, can be extended to other biological samples such as thyroid or brain. Furthermore, Chapter 4 shows that with the right estimation of daily iodine intake and urine volume, a biokinetic model of iodine, built in the AMBER software, can predict urinary iodine concentration with a high degree of accuracy without collecting urine samples.

La lithiase rénale touche environ 10% de la population dans les pays industrialisés. 75% des calculs sont composés majoritairement d'oxalate de calcium; 10% sont composés de phosphate de calcium, 9% d'acide urique, 5% de struvite et moins de 1% de cystine. La composition des calculs dépend des espèces sursaturées dans les urines. Dans la première partie de ma thèse, je décris un modèle murin de cystinurie de type A lié à une mutation spontanée apparue dans la souche de souris 129S2/SvPasCrl. La cystinurie est une maladie autosomique récessive responsable de 7% des lithiases de l'enfant. Les calculs de cystine récidivent fréquemment et la cystinurie est caractérisée par un risque élevé de développer une insuffisance rénale chronique. Le modèle que nous proposons permet de tester de nouvelles thérapeutiques. Il met aussi en évidence une atteinte parenchymateuse avec un infiltrat inflammatoire associée aux calculs de cystine. Dans la deuxième partie de ma thèse, j'évalue le rôle des Escherichia coli dans la genèse des calculs phospho-calciques. J'ai étudié en microscopie électronique à balayage des calculs phosphocalciques issus de patients et analysé les propriétés calcifiantes de différentes souches bactériennes sauvages et mutées dans des milieux spécifiques et dans de l'urine. En milieu synthétique le rôle des phosphatases est déterminant mais le type de source de carbone influence l'activité des phosphatases. Dans les urines, certains E. coli induisent la précipitation de phosphate de calcium aussi rapidement que les Klebsiella sans moduler le pH. Le type de source de carbone dans les urines semble déterminant pour moduler la biominéralisation. / Urolithiasis is a disease that corresponds to the presence of kidney stones in the urinary tract. It affects about 10% of the population in industrialized countries. About 75% of the stones are made of calcium oxalate. Less than 10% are made of calcium phosphate, 9% are made of uric acid, 5% are made of struvite and less than 1% are made of cystine. The composition depends on the species that are supersaturated in urine. In the first part of my thesis I will present a mouse model of cystinuria type A. Cystinuria is an autosomal recessive disease caused by the mutation of either SLC3A1 gene encoding for rBAT (type A cystinuria) or SLC7A9 gene encoding for b0,+AT (type B cystinuria). In 129S2/SvPasCrl strain, we evidenced cystine crystals, as well as cystine stones. We observed an heterogenous inflammatory infiltrate and cystine tubular casts in the parenchyma. We identified a single mutation and a defect of the heavy subunit rBAT. This mouse model could allow for further pathophysiological studies and may be useful to analyse the crystal/tissue interaction in cystinuria. In the second part of my thesis I will test the pathogenesis of E. coli in calcium phosphate stones. In this part, I observed calcium phosphate stones by scanning electron microscopy. I also analysed calcifying properties of wild type bacteria and mutant bacteria in urine or in specific calcifying medium. In synthetic medium phosphatases play a role in calcification but carbohydrate source seems to play a major part in the phosphatase activity. In urine some E. coli induce phosphate calcium precipitation as quickly as Klebsiella does.