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Deep row incorporation of biosolids is an alternative land application method that may allow higher than currently permitted mine land reclamation application rates. Biosolids treated by various processes possess characteristics that uniquely affect metal solubility and mobility due to their influence on metal speciation. The objectives of this research were to compare the effects of biosolids stabilization type and rate on heavy metal solubility, mobility, and speciation. Two rates each of Alexandria, (Virginia) anaerobically digested (213 and 426 dry Mg ha-1) and Blue Plains (Washington, DC) lime-stabilized (329 and 657 dry Mg ha-1) biosolids were placed in trenches at a mineral sands mine reclamation site in Dinwiddie County, Virginia in June and July 2006. Vertical and lateral transport of heavy metals from the biosolids seams were determined by analyzing leachate collected in zero tension lysimeters below the trenches and suction lysimeters adjacent to the trenches. Chloride (Cl-), sulfate (SO42-), nitrate (NO3-), phosphate (PO43-), dissolved organic carbon (DOC), and pH were also determined within the dissolved fractions (< 0.45 µm) collected on September 8, 2006, November 3, 2006, January 5, 2007, June 8, 2007, and September 7, 2007 as input for the speciation program MINTEQA2. Silver, Cd, Pb, and Sn did not move vertically or laterally to any significant extent. Lime-stabilized biosolids produced higher cumulative metal mass transport per sampling period for Cu (967 g ha-1), Ni (171 g ha-1), and Zn (1027 g ha-1) than the anaerobically digested biosolids and control during the 15-month period following entrenching. Barium mass loss was similar for both biosolids. All metals moved primarily with particulates. MINTEQA2 predicted the majority of the metals within the dissolved fraction were present as free ions. As pH decreased and time increased, the amount of association with fulvic acids decreased allowing more free ions and binding with inorganic ligands. Little movement into groundwater demonstrates that anaerobically digested and lime-stabilized biosolids can be land-applied at high rates with little concern of heavy metal contamination of groundwater under these conditions. / Master of Science

Divergence in the face of gene flow is perhaps the most wildly disputed subject among researchers through time. The debate is an old one and we find its origin as far back as the era of Darwin. The theories dealing with sympatric and parapatric speciation, its processes and ecological conditions, are numerous and the empirical data supporting the ideas is constantly growing. However, the reach of a consensus almost seem as distant as ever. Two fundamental prerequisites can be identified for the evolution of divergence with gene flow, the act of disruptive selection, and the development of assortative mating. A set of models in which speciation with gene flow seem particularly likely is when a shift occurs in host preference in phytophagous insects and mating takes place on the host. In the work behind this thesis, the role of assortative mating in the initial stages of sympatric and parapatric speciation has been studied, as has the interaction between assortative mating and inbreeding and how it effects speciation in small sympatric populations, an aspect not much attended to earlier in the literature. My results show that assortative mating based on resource preference, can evolve rapidly upon secondary contact, and even in parapatric populations with a migration rate of 8% (13-15 individuals) per generation. However for assortative mating to be maintained selection against hybrids is needed. My results also suggests that small inbred populations have a hard time coping with strong assortative mating an as a consequence tend to relax their mating preferences to avoid inbreeding depression. Based on these results, I advocate for the importance of considering not only assortative mating in itself, but also the joint effects of assortative mating and inbreeding when dealing with theories of speciation with gene flow.

Dans le circuit primaire des réacteurs nucléaires à eau pressurisée, le bore participe au contrôle des réactions de fission. Le traitement de cette solution génère des déchets aqueux contenant une forte concentration en bore (de 1 à 3 mol/L). Le conditionnement de ces déchets à l'aide d'un ciment silico-calcique est compliqué par le fort pouvoir retardateur des ions borate sur l'hydratation du liant. Un traitement des déchets à la chaux est nécessaire pour précipiter les ions borate sous forme d'hexahydroborite. Cette stratégie, si elle limite le retard d'hydratation, ne le supprime pas. Par ailleurs, l'hexahydroborite est instable en milieu cimentaire et se convertit dans le temps en boroaluminate de calcium. Une autre approche pourrait consister à utiliser un ciment sulfoalumineux bélitique à forte teneur en ye'elimite. Ce liant présente en effet l'avantage de former en quantité importante des phases de type AFm et/ou AFt lors de son hydratation, phases qui peuvent incorporer des ions borate dans leur structure.Au cours de ce travail, l'hydratation de ciments sulfoalumineux par des solutions de borate de sodium a été étudiée au jeune âge et à plus long terme (sur une durée de 2 ans) dans l'objectif de préciser l'influence d'un ensemble de paramètres (pH du déchet, concentration en bore, taux de gypse du ciment) sur la vitesse d'hydratation du liant, la nature des hydrates formés, et les propriétés du matériau obtenu (résistance mécanique, stabilité dimensionnelle). Pour ce faire, une démarche analytique, procédant par complexification progressive des systèmes étudiés, a été mise en œuvre. Ainsi ont été successivement abordées la spéciation du bore en solution alcaline, l'étude des phases précipitant au sein des systèmes {CaO, B2O3, Na2O, H2O}, {CaO, B2O3, Al2O3, H2O} et {CaO, Al2O3, B2O3, SO3, H2O}, puis celle des pâtes de ciment gâchées avec une solution boratée simulant le déchet. L'approche expérimentale a été complétée par des modélisations thermodynamiques s'appuyant sur une base de données spécialement développée pour les besoins de l'étude.Il apparaît que le gypse joue un rôle primordial dans le contrôle de la réactivité du ciment. L'ajout de gypse fixe, par un mécanisme indirect, le pH de la solution interstitielle à une valeur proche de 11, ce qui favorise la précipitation transitoire d'un composé boraté faiblement cristallisé, l'ulexite. La dissolution des phases anhydres du ciment est alors fortement ralentie jusqu'à l'épuisement du gypse, conduisant ainsi à des retards de prise considérables. En l'absence de gypse, le retard à l'hydratation est de plus faible amplitude. Dans ces conditions, le pH de la solution interstitielle atteint des valeurs plus élevées, ce qui permet de déstabiliser rapidement l'ulexite. A plus long terme, les ions borate sont incorporés au sein d'une phase de type AFt, en solution solide avec les ions sulfate. Les résultats obtenus permettent de conclure que ce sont les ciments sulfo-alumineux contenant une faible teneur en gypse qui sont les plus adaptés au conditionnement de solutions à forte concentration en bore. / In the primary circuit of pressurized water reactors, boron helps controlling the fission reactions. The treatment of this solution produces aqueous low-level or intermediate-level and short lived radioactive with a high boron concentration (up to 1 to 3 mol/L). Stabilization/solidification of such wastes with calcium silicate cement is complicated by the strong retarding effect of borate ions on cement hydration. A calcium hydroxide addition is required to precipitate borate ions into hexahydroborite. With this approach, the hydration delay is limited, but not suppressed. Besides, hexahydroborite is unstable in the cement paste and is progressively converted into a hydrated calcium boroaluminate phase. Another strategy may consist in using belite calcium sulfoaluminate cement with high ye'elimite content. During hydration, this binder forms indeed large amounts of AFm and/or AFt phases which can incorporate borate ions into their structure.In this work, hydration of calcium sulfoaluminate cement by borated solutions was investigated at early age, and over a 2-year period, in order to determine the influence of a set of parameters (boron concentration and pH of the waste, gypsum content of the cement) on the hydration rate of the binder, on the phase assemblage formed, and on the properties of the resulting material (mechanical strength, volume change). An analytical approach was adopted, based on a progressive increase in the complexity of the investigated systems. The focus was successively placed on the speciation of boron in alkaline solution, on the study of the phases formed within the {CaO, B2O3, Na2O, H2O}, {CaO, B2O3, Al2O3, H2O} and {CaO, Al2O3, B2O3, SO3, H2O} systems, and on the characterization of cement pastes prepared with a borate solution which mimicked the waste. The experimental approach was completed by thermodynamic modelling using a database specially developed for the needs of the study. Gypsum appears to play a key role in controlling the reactivity of cement. The gypsum addition sets, by an indirect mechanism, the interstitial solution pH at a value close to 11, which promotes the precipitation of a poorly crystallized borated compound, ulexite. Dissolution of the anhydrous phases is strongly slowed down until the exhaustion of gypsum, and major delays are observed. Without any gypsum, the hydration delay is shorter. Under these conditions, the pore solution pH reaches higher values after mixing. Ulexite is consequently quickly destabilized. Borate anions are then incorporated into a mixed borate/sulphate AFt type phase. It appears that calcium sulfoaluminate cements with low gypsum contents should be recommended to solidify borated solutions.

Facile procedures based on hyphenated ion-exchange chromatography (IEC) and inductively coupled plasma mass spectrometry (ICP-MS) were developed to determine conditional stability constants, speciate chromium species and investigate the reduction of Cr(VI). 1. Improvements were made to a method previously developed to determine the conditional stability constant, Kf’, and chelation number, n, using IEC-ICP-MS. This method allowed the accurate determination of the conditional stability constant of a simple system. However, the corresponding chelation number was significantly different to the expected value because the principal assumption, i.e. that the ligand was in excess, was not realized in the experimentation. Furthermore, it neglected complexes other than that formed with EDTA4-. By taking into account these factors, accurate Kf’ and n were obtained for Co-EDTA and Zn-EDTA systems. 2. A simple method was developed for chromium speciation analysis at sub-µg L-1 level in potable water by IEC-ICP-MS. Cr(VI) and Cr(III) were separated on IonPac® AG-7 guard column within 7.5 minutes using gradient elution with 0.1 M ammonium nitrate and 0.8 M nitric acid. H2 collision/reaction interface gas eliminated chlorine-based and carbon-based polyatomic interferences on Cr detection. Water samples were analyzed directly, without any pretreatment. The accuracy of the method was verified through accurate analysis of riverine water certified reference material. Limits of detection of 0.02 and 0.04 µg L-1 for Cr(VI) and Cr(III), respectively, were obtained. 3. This speciation analysis method was then used for kinetics studies of Cr(VI) reduction in acidified riverine water. Water was spiked with Cr(VI), with or without Cr(III), and evolution of each Cr species with time was monitored by speciation analysis, showing that the reduction of Cr(VI) was a pseudo first order reaction. By plotting the logarithm of the peak area ratio of the instant Cr(VI) concentration over that of the original spiking versus time, the reaction rate constant was obtained as the slope. The reduction rate increased with decreasing pH and increasing temperature. The activation energy of the reaction at pH 1.3 was calculated using an Arrhenius plot. This method offers the advantages of small sample consumption, minimal sample manipulation, and easy data interpretation. / Thesis (Ph.D, Chemistry) -- Queen's University, 2010-09-30 08:05:27.342

L’écotoxicité des éléments traces vis-à-vis du vivant est contrôlée par leur bioaccessibilité, leur biodisponibilité et leurs interactions avec le(s) site(s) d’action à l’intérieur des organismes. Dans le cas des certains éléments, l’existence dans le milieu naturel de plusieurs formes redox ayant des propriétés différentes doit aussi être prise en considération. Dans le cas spécifique du Cr, le consensus général considère le Cr(III) comme moins écotoxique que le Cr(VI). Toutefois, plusieurs études récentes soulignent que ce consensus devrait être réexaminé. Plus particulièrement, une connaissance insuffisante de la spéciation du Cr(III) pendant les tests en laboratoire pourrait avoir conduit à une sous-estimation de sa biodisponibilité et écotoxicité. Ce travail de thèse s’intéresse donc aux relations entre spéciation, biodisponibilité et bioaccumulation du Cr(III) et Cr(VI) dans différents modèles biologiques pour mieux appréhender leur potentiel écotoxique ainsi que leurs mécanismes d’interaction avec le vivant. Des études ont été menées chez les algues Pseudokirchneriella subcapitata et Chlamydomonas reinhardtii, le bivalve Corbicula fluminea et des cultures de cellules d’ovaire d’hamster chinois (CHO). L’ensemble des résultats de ce travail suggère que la validité du paradigme ‘le Cr(VI) est plus écotoxique que le Cr(III)’ serait dépendante des conditions d’exposition et du modèle biologique utilisé. Ce paradigme, accepté tant par la communauté scientifique que par les gestionnaires environnementaux, nécessite donc un réexamen afin d’assurer une meilleure gestion des risques liés au Cr / The ecotoxicity of the trace elements to the living organisms is controlled by their bioaccessibility, their bioavailability and their interactions with the site(s) of action inside the organisms. In the case of certain elements, the existence in the natural environment of several redox forms having different properties must also be taken into consideration. In the specific case of Cr, general consensus considers Cr(III) to be less ecotoxic than Cr(VI). However, several recent studies highlight that this consensus should be re-examined. In particular, insufficient knowledge of Cr(III) speciation during laboratory tests may have led to an underestimation of its bioavailability and ecotoxicity. This work focuses on the relationship between speciation, bioavailability and bioaccumulation of Cr(III) and Cr(VI) in different biological models in order to better understand their ecotoxic potential as well as their mechanisms of interaction with living organisms. Studies have been conducted on the algae Pseudokirchneriella subcapitata and Chlamydomonas reinhardtii, the bivalve Corbicula fluminea and cultures of Chinese hamster ovary cells (CHO). The results of this work suggest that the validity of the paradigm ‘Cr(VI) is more ecotoxic than Cr(III)’ would be dependent on the exposure conditions and the used biological model. This paradigm, accepted by both the scientific community and the environmental managers, requires a reassessment to ensure a better management of Cr risks

La synthèse de particules d'oxydes mixtes en solution aqueuse est souvent difficile à contrôler en raison de la réactivité potentiellement différente des espèces qui coprécipitent. L’objectif de la thèse est de tenter de comprendre et piloter la synthèse dans le cas du système de particules d’oxydes mixtes de titane et d'étain, choisi en raison de l'existence d'une solution solide sur toute la gamme de composition et de la possibilité de recourir à une précipitation homogène plus simple à modéliser que le mélange réactif. Les synthèses sont réalisées par thermohydrolyse avec chauffage micro-ondes de solutions acides, fournissant des particules directement cristallisées avec des temps de réaction réduits. Les résultats des synthèses, à savoir le rendement et la composition du solide, sont modélisés par un calcul de sursaturation nécessitant la connaissance de la spéciation des solutions préparées. Cette dernière est calculée par la détermination à la température de thermohydrolyse des constantes d’équilibres en solution à partir de données bibliographiques et de mesures de solubilité à basse température d'une part et d'autre part de modélisation de la dépendance thermique des grandeurs thermodynamiques. Enfin, des nanocomposites Anatase-Rutile ont été obtenus par coprécipitation de titane avec de petites quantité d’étain et les propriétés photocatalytiques de ces nanoparticules ont été testées. / The synthesis of mixed oxide particles in aqueous solution is often difficult to control because of the potentially different reactivity of coprecipitating species. The aim of the thesis is to try to understand and control the synthesis in the case of mixed titanium oxide particles and tin system, chosen because of the existence of a solid solution over the entire range composition and the possibility of using a simpler homogeneous precipitation to model the reactant mixture. The syntheses are carried out by thermal hydrolysis of acidic solutions with microwave heating, providing particles directly crystallized with reduced reaction times. The results of the synthesis, namely the yield and composition of the solid, are modeled by a calculation of the supersaturation requiring knowledge of the speciation of the prepared solutions. This is calculated by determining the temperature of thermal hydrolysis in solution equilibrium constants from bibliographic data and low-temperature solubility measurements on the one hand and on the other hand, modeling of the temperature dependence of the thermodynamic. Finally, Anatase-Rutile nanocomposites were obtained by coprecipitation of titanium with small amounts of tin and the photocatalytic properties of these nanoparticles were tested

Thesis (M. Sc.(Chemistry)) -- University of Limpopo, 2017. / Great Letaba and Mokolo Rivers are major sources of water for domestic use, agriculture and recreational activities in Limpopo Province, South Africa. These Rivers are predisposed to pollution sources from atmospheric deposition of mine dust, emissions from power stations and burning fuel, return flows from agriculture and municipal wastewater discharges and sewage effluents, which may potentially affect the quality of water and the inhabiting biota. Arsenic (As) is an element of prime concern in aquatic systems exposed to such pollution sources due to its toxicity to humans and aquatic life. The quantification and speciation of As in Mokolo and Great Letaba Rivers is important to assess the current levels and predict future trends in the quality of the two rivers. Speciation of As in water and sediments is crucial since the toxicity depends on its chemical forms. In this study, various analytical approaches were explored to precisely identify and quantify different As species in water and sediment samples collected from Great Letaba and Mokolo Rivers. Sample preparation was carried out with an intensive care to efficiently identify and quantify As species. Identification of each species in the samples was based on matching standard peaks with retention times by simple injection of standards of As species into Hamilton PRP X100 column. The chromatographic separation and determination of As3+, dimethylarsinic acid (DMA), monomethylarsonic acid (MMA) and As5+ in water and sediment samples were achieved by on-line coupling of high performance liquid chromatography (HPLC) to inductively coupled plasma-mass spectrometry (ICP-MS). A novel extraction method for As species in sediments based on 0.3 M (NH4)2HPO4 and 50 mM EDTA showed no species interconversion during extraction. Baseline separation of four As species was achieved in 12 minutes using gradient elution with 10 mM and 60 mM of NH4NO3 at pH 8.7 as mobile phases. The analytical figures of merits and validation of analytical procedures were assessed and adequate performance and percentage recoveries ranging from 81.1 – 102% for water sample and 73.0 – 92.0% for sediments were achieved. The As species concentration in water and sediment samples were found in the range 0.224 – 7.70 μg/L and 74.0 – 92.0 ng/g, respectively. The DMA was not detected in both water and sediment samples. viii The As content in sediments depends on the solid phase partitioning between inorganic As species and trace elements such as iron (Fe), manganese (Mn) and aluminium (Al). Knowledge of the extent of this partitioning is important to evaluate the distribution and pathways of As in water, aquatic organisms and possible exposure of animals and human beings. Therefore, total concentrations of As, Fe, Mn and Al in water and sediment samples were determined using ICP-MS and inductively coupled plasma–optical emission spectrometry (ICP-OES). The analytical procedures were validated using standard reference materials (SRMs) with percentage recoveries of trace elements ranging 84.0 – 95.6% for water samples and 75.0 – 120% for sediments. The As, Fe, Mn and Al concentrations obtained were further assessed for safe drinking water, irrigation water and for sediments quality about standard guidelines. Moreover, As species concentrations correlated with Fe, Mn and Al and the observed interactions depend on the adsorption capacities between As species and these trace elements. The inorganic species in water samples were also determined by employing off-line mode of solid phase extraction (SPE) procedure using multi-walled carbon nanotubes (MWCNTs) impregnated branched polyethyleneimine (BPEI) as an adsorbent material. The MWCNTs-BPEI characterised with X-ray powder diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and Thermogravimetric analysis (TGA) techniques indicated successful modification of the nanomaterial. The MWCNTs-BPEI exhibited selective retention of As5+ in the presence of As3+ in water samples with the achieved pre-concentration factor of 23.3. The retained As5+ was then eluted and detected using ICP-MS. A limit of detection (LOD) of 0.0537 μg/L and limit of quantification (LOQ) of 0.179 μg/L were achieved. The obtained percentage recovery of 81.0% validated the SPE procedure for selective retention of As5+. The As5+ concentrations determined after the SPE procedure were found in the range of 0.204 – 7.52 μg/L, which are in good agreement with As5+ results obtained using HPLC-ICP-MS.

Natürliche Biofilme von zwei urankontaminierten Standorten, dem ehemaligen Uranbergwerk in Königstein (Sachsen) und dem Gebiet der ehemaligen Aufstandsfläche der Gessenhalde (Thüringen), wurden in dieser Arbeit näher untersucht. An beiden Standorten konnte in den Minenwässern die hochmobile, gelöste Uranspezies Uranylsulfat (UO2SO4) als dominierend nachgewiesen werden. Aufgrund der Instabilität vieler kommerzieller Fluoreszenzfarbstoffe bei niedrigen pH-Werten war eine gezielte Anfärbung der Mikroorganismen in den sauren Biofilmen nicht möglich, ohne den pH-Wert der Biofilmproben anzuheben, was die Probenchemie maßgeblich verändert. In Kooperation mit der Firma DYOMICS (Jena, Deutschland) wurden neue, kommerziell nicht erhältliche, säurestabile Farbstoffe erstmals hinsichtlich ihrer Eignung zur Anfärbung von Mikroorganismen in sauren Biofilmen ohne Veränderung des pH-Wertes sowie der sonstigen Probenchemie getestet. Die neuen Farbstoffe DY-601XL, V07-04118, V07-04146 und DY-613 zeigten eine Eignung für solche Färbungen, da sie eine intensive Anfärbung der Mikroorganismen bei niedrigen pH-Werten unter pH 3 – 4 herbeiführen und außerhalb des Emissionsbereiches von Uran fluoreszieren. In dieser Arbeit wurde die Fähigkeit von Euglena Mutabilis-Zellen zur Bioakkumulation des Urans im pH-Wertbereich 3 – 6 in den Hintergrundmedien Natriumperchlorat (9 g/l) oder Natriumsulfat (3,48 g/l) an lebenden Zellen untersucht. Unabhängig vom Medium konnte bei sauren pH-Werten um pH 3 – 4 über 90 % des vorgelegten Urans aus den Probelösungen abgetrennt werden. Die Speziation des an den Euglena-Zellen akkumulierten Urans, wurde mittels laserinduzierter Fluoreszenzspektroskopie (LIFS) untersucht. Es zeigte sich, dass unabhängig vom Hintergrundmedium, Lebenszustand und pH-Wert eine vergleichbare neue Uranspezies an den Zellen gebildet wird. Durch den Vergleich der Daten aus den LIFS-Messungen mit Referenzwerten, konnte die gebildete Uranspezies auf eine Anbindung durch (organo)phosphatische und/oder carboxylische funktionelle Gruppen eingegrenzt werden. Mit Hilfe der zeitaufgelösten FT-IR-Spektroskopie konnte die carboxylische Anbindung des Urans an toten Zellen nachgewiesen werden. Ein Ausschluss der (organo)phosphatischen Komplexierung konnte jedoch mit dieser Methode nicht geführt werden. Untersuchungen zur Lokalisation des Urans an bzw. in den Zellen, mittels der gekoppelten CLSM/LIFS-Technik zeigten erstmals ein Indiz für die intrazelluläre Akkumulation von Uran in den lebenden Zellen. Ergänzende TEM/EDX-Messungen bestätigten die intrazelluläre Aufnahme und belegen eine Akkumulation in runden bis ovalen Zellorganellen, bei denen es sich vermutlich um Vakuolen oder Vakuolen-ähnliche Vesikel handelt. An den toten Zellen konnte mit diesen Methoden kein Uran detektiert werden. Dies lässt auf eine passive, homogen verteilte Biosorption des Urans an die verfügbaren Bindungsplätze an der Zelloberfläche der toten Biomasse schließen.

In an attempt to correlate genetic data with possible species delineation, this study investigates the presence of chromosomal variants between the North Atlantic bottle nose dolphin, Tursiops truncatus, and the North Pacific bottle nose dolphin, T. gilli. Blood samples were obtained from oceanaria in the United States. Location of capture was correlated with karyotype to compare chromosome morphology with geographic range.