An improved understanding of the geochemical partitioning of trace metals and tributyltin (TBT) in sediments is of great importance in risk assessment and remedial investigation. The aim of this thesis was to examine the distribution and partitioning behaviour of trace metals and TBT in benthic, estuarine sediments. This was achieved by a series of field- and laboratory-based studies investigating factors controlling the geochemical behaviour of trace metals and TBT in sediments from south-east Queensland, Australia. The distribution and enrichment of selected trace metals in benthic sediments of the Southport Broadwater (a semi-enclosed coastal body of water adjacent to the Gold Coast city, south-eastern Queensland, Australia) was studied. Sediment contamination for Cd, Cr, Cu, Ni, Pb, Sn and Zn was assessed by (1) comparison with Australian sediment quality guidelines, (2) calculation of the index of geoaccumulation based on regional background values, and (3) geochemical noi-malisation against Al (i.e. the abundance of alumino-silicate clay minerals). Based on this approach, several sites were found to be strongly enriched with Cu, Pb, Sn and Zn, arising from sources related to either urban runoff or vessel maintenance activities. The geochemical partitioning of Cu, Pb and Zn was examined in sediments collected from three of these sites of sediment contamination. Total Cu, Pb and Zn concentrations in coarse-textured (65 to 90 % sand sized particles), sub-oxic sediments (Eh + 120 to +260 mV) ranged from 8.3 to 194 mg/kg for Cu, 16.3 to 74.8 mg/kg for Pb and 30.1 to 220 mg/kg for Zn, and were related to vertical trends in sediment texture. The association of Cu, Pb and Zn with amorphous oxides, crystalline oxides and organic matter was linearly dependent on the abundance of each phase. For retention by amorphous oxide minerals, the trace metal retention ranged from 5.2 to 23.7 mgcjgFe oxide as Fe for Cu, 1 2.8 to 21 .5 mgpb/gFe oxide as Fe for Pb, and 23. I to 85.7 mgm/gFe oxide as Fe for Zn. Corresponding values for association with crystalline oxides were an order of magnitude less than those for amorphous oxides, indicating a weaker affinity of trace metals for crystalline oxides. The relationships describing association with organic matter ranged from 17.6 to 54.0 mgcu/gorg c for Cu, 6.1 to 9.6 mgpb/gorg c for Pb and 6.4 to 16.4 mgzn/gorg c for Zn. The in-situ solid/pore-water partitioning of TBT and the degradation products, dibutyltin (DBT) and monobutyltin (MBT), was determined for an estuarine sediment profile with previously identified elevated Sn concentrations. Total butyltin levels were (depending on depth) 220 to 8750 jig/kg for TBT, 150 to 5450 jig/kg for DBT and 130 to 4250 jig/kg for MBT. Pore-water butyltin concentrations ranged from 0.05 to 2.35 jig/L for TBT, 0.07 to 3.25 jiglL for DBT, and 0.05 to 0.53 J.tgIL for MBT. The organic carbon normalised distribution ratios (Doc) were similar for TBT, DBT and MBT, and were io to 106 L/kg. Values for the Butyltin Degradation Index (BDI) were larger than I at depths greater than 10 cm below the sediment/water-column interface, indicating that substantial TBT degradation has occurred in the sediments. This suggests that natural attenuation may be a viable sediment remediation strategy. Factors controlling the partitioning behaviour of Cu, Pb and Zn in nonsulfidic, estuarine sediments were examined in controlled laboratory-based studies with the use of combined sorption curve - sequential extraction analysis. This allowed determination of sorption parameters for Cu, Pb and Zn partitioning to individual geochemical fractions. Partitioning behaviour in sulfidic sediments was also determined by sequentially extracting Cu, Pb and Zn from synthetic sulfide minerals, and from natural sediment and pure quartz sand after spiking with acid-volatile sulfide (AVS). Trace metal sorption to the 'carbonate' fraction (pH 5, NaOAc extraction) increased with metal loading due to saturation of sorption sites associated with the 'Fe-oxide' (NH2OH.HCI extraction) and 'organic' (H202 extraction) fractions in non-sulfidic sediments. Freundlich isotherm parameters describing sorption to the 'Fe-oxide' and 'organic' fractions were dependent on the sediment Fe-oxide and organic carbon content, respectively. Sequential extraction of Cu from pure CuS, AVS-spiked sediment and AVS-spiked quartz sand showed that AVS-bound Cu was quantitatively recovered in association with the 'organic' fraction. However, some AVS-bound Pb and Zn were recovered by the NH2OH.HCI step (which has been previously interpreted as 'Fe-oxide' bound metals) in the sequential extraction procedure used in this study. This indicates that the sequential extraction of Pb and Zn in sulfidic sediments may lead to AVS-bound metals being mistaken as Fe-oxide bound species. Caution should therefore be exercised when interpreting sequential extraction results for Pb and Zn in anoxic sediments. Tributyltin (TBT) sorption to four natural sediment samples in artificial seawater was also examined under a range of modified pH and salinity conditions in controlled laboratory-based studies. Three of the sediment samples were relatively pristine with regard to TBT contamination, but the fourth was a TBT-contaminated sediment from a commercial marina. Sorption of TBT was described well by linear sorption isotherms, with distribution coefficients ranging from 6.1 to 5210 L/kg depending on pH and salinity. Sediment organic C content and particle size distribution were important determinants of sorption behaviour. The presence of resident TBT in the contaminated marina sediment caused a substantial reduction in TBT sorption due to satuaration of high selectivity sites. Desorption of TBT from the marina sediment was described by relatively large observed distribution coefficients ranging from 5100 to 9400 L/kg, suggesting that aging effects may reduce sorption reversibility. Increased artificial seawater salinity generally reduced TBT sorption at pH 4 and pH 6, but enhanced TBT sorption at pH 8. Regardless of salinity, maximum sorption of TBT was observed at pH 6, which is attributed to an optimal balance between abundance of the cationic TBT species and deprotonated surface ligands. Consideration of aqueous TBT speciation along with octanol-water partitioning behaviour suggest that hydrophobic partitioning of TBTCI to non-polar organic matter was important for pH (up to) 6, whilst partitioning of TBTOH was important at higher pH. The effect of aging on the solid/pore-water partitioning and desorption behaviour of TBT in sediments was examined. Three sediment samples with contrasting physical and chemical properties were spiked with 10 mg/kg TBT and aged under sterile conditions for periods of time ranging from I to 84 days. Aging had a negligible effect in a sandy sample with very low organic carbon content (0.2 % w/w). In contrast, for samples with larger amounts of organic carbon (2.6 and 4.8 % w/w), the effect of aging on the solid/pore-water partitioning behaviour was significant. For these samples, the apparent distribution coefficients (Ks) obtained from sequential two hour desorption experiments exhibited a two-fold increase between spiked sediments subjected to aging for 1 day and 84 days. This study demonstrates that aging effects may be an important aspect of TBT fate in contaminated sediments. Overall, the results described in this thesis demonstrate that environmental factors (i.e. pH, salinity, Eh, aging) and sediment composition (i.e. abundance of fine alumino-silicate minerals, organic matter, Fe-oxides, reactive sulfides) exert substantial effects on trace metal and TBT partitioning. The current reliance on measurement of total trace metal and TBT concentrations in contaminated sediment management may consequently lead to inaccurate estimates of environmental risk and inappropriate remediation measures if other factors regulating contaminant distribution and partitioning are ignored.

Includes 25 papers previously published in Journals / 114, 16 leaves : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (D.Sc.)--University of Adelaide, Dept. of Biochemistry, 1975

Pour quantifier l'influence des activités humaines sur le climat et en particulier sur la compositionchimique de l'atmosphère, il est primordial de disposer de mesures continues et homogènes. C'estpourquoi l'objet de ce travail de thèse a consisté, dans un premier temps, à installer une nouvellestation d'observation (OASIS pour Observations Atmosphériques par Spectrométrie InfrarougeSolaire) sur le toit de l'Université Paris-Est à Créteil, pour mesurer des spectres d'absorption solairedans l'infrarouge, en vue d'analyser les concentrations de gaz traces et leurs différentes variabilitéstemporelles. Cette étude est centrée sur deux molécules clés de l'atmosphère impliquées, à diverseséchelles, dans les problèmes environnementaux actuels : l'ozone (O3) et le monoxyde de carbone(CO). Le développement de la méthode expérimentale et l'adaptation du code d'inversion (PROFFIT)a permis de restituer les colonnes totales et partielles de ces deux espèces. Pour valider lesperformances de cet instrument et de la méthode employée, les résultats des analyses de OASIS ontété comparés avec diverses données corrélatives provenant de mesures au sol (SAOZ pour l'O3), desatellites (IASI, GOME-2, OMI, pour l'O3, et MOPITT et IASI pour le CO) et de modèles globaux(REPROBUS pour l'O3 et MOCAGE pour le CO). Les résultats ont montré de très bons accords etprouvent la qualité du spectromètre à moyenne résolution spectrale, de la station OASIS, pour mesurerles concentrations de l'O3 et du CO atmosphérique.Une partie de ce travail a également concerné la validation des performances des instruments spatiauxactuels de détection de l'ozone atmosphérique, grâce à la campagne de mesures (avril-mai 2009) quej'ai réalisée à Izaña (Ténérife). Cette station, située en région sub-tropicale, à 2370 m d'altitude et enmilieu non pollué, est intégrée dans le réseau NDACC, et possède un spectromètre à haute résolutionspectrale. Les concentrations d'ozone issues des inversions des spectres mesurés ont été comparéesaux données fournies par un instrument au sol (Brewer, situé sur le même site) et par plusieursinstruments satellitaires (IASI, OMI, GOME-2). Les résultats ont présenté d'excellents accords.Les diverses variabilités temporelles observées à Izaña et à Créteil (saisonnière, inter-journalière,diurne et événements extrêmes) ont été interprétées et les capacités respectives

Thurston montre comment munir le complémentaire du noeud de huit dans S³ d'une structure hyperbolique réelle complète en identifiant cet espace au recollement de deux tétraèdres. Falbel prolonge cette méthode dans le cadre CR-sphérique. Il obtient ainsi une géométrisation CR branchée pour le complémentaire du noeud. Cette approche passe par la résolution d'équations polynomiales dont les inconnues sont des invariants caractérisant les tétraèdres. La résolution de ces équations nous a permis de construire des représentations de groupes fondamentaux à valeur dans PU(2,1) pour des variétés non compactes. Dans le cas réel, la rigidité des structures hyperboliques complètes est assurée par le théorème de Mostow, tandis qu'il existe des représentations de variétés CR-sphériques compactes admettant des déformations. Le calcul du rang des équations précédemment évoquées permet de conclure à la rigidité d'une structure CR-sphérique triangulée dès qu'elle existe. Pour les représentations que nous avons construites, le rang des équations est systématiquement maximal. Dans le cas général, nous donnons des minorations du rang. Dans une partie indépendante, nous étudions le corps de trace de sous-groupes de SU(n,1). Nous établissons que pour un groupe G dans SU(2,1) Zariski dense qui contient une transformation parabolique, quitte à conjuguer G, son corps de trace est exactement le corps engendré par les coefficients de ses matrices.

The atmospheric transport of various substances from the continents to the oceans plays an important role in biogeochemical processes. Trace metals, iron in particular is of great interest as its availability regulates the growth of phytoplankton over large areas of the ocean. This dissertation focuses on examining and characterizing the factors that affect the solubility of trace metals in Miami and Barbados aerosols and precipitation, in particular species that could play a role in surface seawater biogeochemistry (Fe and trace metals such as Al, V, Cr, Mn, Cu, Co, Ni, Zn, As, Tl, Ba, Cd, Pb, Th, Ti, Zr, and REE's). To enable this study existing methods of colorimetric spectroscopic and inductively coupled plasma mass spectrometry analysis were improved and modified. This dissertation examines several issues related to source inputs: 1.) Are single spot sources within the North African dust source distinguishable after long transport by their bulk metal composition and thus important in the characteristics of individual mineral dust samples? 2.) What is the temporal variability and controlling factors in trace metal solubility in trade wind aerosols collected over Barbados? 3.) Which factors control the observed trend of speciation and increasing iron solubility in decreasing aerosol loading? Additionally a kinetic model of species specific iron (II) to iron(III) oxidation kinetics in NaCl Brines was conducted at nano-molar levels. This study greatly expands the ability to predict rates of iron oxidation at concentrations closer to those observed in natural systems.

We give an explicit construction of the trace on the algebra of quantum observables on a symplectic orbifold and propose an index formula.

On démontre dans le cas de caractéristique positive un lemme fondamental conjecturé par Jacquet et Mao pour le groupe métaplectique. On utilise les arguments de B.C. Ngo pour le lemme fondamental de Jacquet-Ye (B.C. Ngo, 1999) [[6]] et une étude géométrique de lʼextension métaplectique.

Graduation date: 1991

Around 1990, Arthur proved a local (ordinary) trace formula for real or p-adic connected reductive groups. The local trace formula is a powerful tool in the local harmonic analysis of reductive groups. One of the aims of this thesis is to establish a local twisted trace formula for certain non-connected reductive groups, which is a twisted version of Arthur’s local trace formula. As an application of the local twisted trace formula, we will prove some twisted orthogonality relations, which are generalizations of Arthur’s results about orthogonality relations for tempered elliptic characters. To establish these relations, we will also give a classification of twisted elliptic representations.

Provenance in the lower Belt-Purcell Supergroup is constrained based on geochemical systematics and chemical monazite ages of argillites and sandstones. Rare earth element (REE), Cr-Ni, and Th/Sc-Sc systematics is equivalent for both facies and consistent with a dominantly post-Archean source area. Detrital monazite chemical ages restrict major provenance for the Appekunny and Grinnell sandstones and argillites to Paleoproterozoic terranes at ~1800-1600 Ma, minor contributions at ~1600-1500 Ma, and marginal contributions from Archean terranes at ~2600, likely in Laurentia. Similar detrital age spectra for monazites of argillites and sandstones of the Appekunny Formation are consistent with a common provenance for the two facies.</p> <p>The Belt-Purcell sequence records three major diagenetic stages displayed in argillites and sandstones: (1) K-addition and rare earth element post-Archean upper continental crust (PA-UCC)-like pattern; (2) a stage characterized by heavy REE enrichment relative to light REE and HFSE fractionation, and U and Ce mobility; and (3) local dolomitization with REE and high field strenght elements (HFSE) mobility. REE and HFSE mobility are interpreted as the result of oxidized alkaline brines developed by dissolution of evaporites. Monazites from the Appekunny and Grinnell formations differ compositionally and texturally in two groups. Rounded or inclusions with ages >~1400 Ma, interpreted as detrital, have higher Th2O, Y2O3 and lower LREE/HREE contents than euhedral individual monazite grains with chemical ages <~1400 Ma that posses opposed compositional characteristics, and viewed as diagenetic. Monazites that span <~1400 to 300 Ma could be the result of basinal brine activity during stages (2) and (3). </p> <p>Chemical index of alteration (CIA) for argillites and sandstones, corrected for a diagenetic K-addition average 73 and 66 respectively. These results, coupled with correlation of CIA with Eu/Eu*, low K/Cs ratios, and low Sr, Ca, and Na relative to PA-UCC, could be interpreted as the result of an moderate weathered provenance in a hot, wet climate being drained by a large-scale river system. Presence of minor pristine feldspars lowers the CIA values, and may signify minor contributions from proximal source with short-river transport under the arid to semi-arid climate in the depositional setting. Moderate to intense weathering of the larger provenance may be associated with elevated levels of atmospheric CO2 degassed from a mantle plume implicated in the rifting of the supercontinent Columbia at ~1500 Ma.