Les nanoparticules de fer manufacturées (NPs-Fe) sont des matériaux de taille nanométrique dont l’utilisation s’est, depuis peu, étendue à des domaines environnementaux. Leur dispersion dans les milieux aqueux et solides, et leurs interactions avec le vivant soulèvent toutefois encore de nombreuses questions. Dans la première partie de cette étude, nous conduisons un travail approfondi de caractérisation des NPs-Fe et précisons comment ces propriétés sont impliquées dans les processus contrôlant la stabilité colloïdale puis la réactivité chimique (capacité d’adsorption du cuivre) des NPs-Fe en solution aqueuse. Des modifications à la fois surfaciques et cristallochimiques sont appliquées afin de mettre en évidence le rôle clés de la chimie de surface des NPs-Fe. Dans cette étude, il est montré que les acides humiques limitent l’agrégation des NPs-Fe et procurent des sites d’adsorption pour les métaux. Les conditions physico-chimiques du milieu s’avèrent également jouer un rôle crucial. Le pH modifie notamment la charge de surface des NPs-Fe et les forces d’interactions électrostatiques qui en résultent. Dans un deuxième temps, nous étudions les interactions entre les NPs-Fe et les végétaux, en solution puis dans un sol. Après 63 et 57 jours, les mesures de susceptibilité magnétique montrent que les NPs-Fe s’accumulent au niveau des racines avant d’être transloquées, en moindre quantité, dans les parties aériennes des plantes. La réponse des plantes à l’exposition aux NPs-Fe se traduit par une augmentation de la biomasse végétale et des teneurs en chlorophylles et une diminution de la peroxydation lipidique. / Engineered Iron Oxide Nanoparticles (IONPs) are specific nanoscale materials that have recently been used into wide environmental applications. The dispersion of IONPs into soils and waters, as well as their interactions with living organisms, raise many scientific issues. The first part of this work is intended to provide a thorough characterization of IONPs in aqueous solution, from their intrinsic physico-chemical properties to their colloidal behavior and chemical reactivity. Surface modifications are applied to evidence the key role of surface chemistry towards most interactions IONPs encounter. In particular, humic acid reduce NPs-Fe aggregation and display a high adsorption capacity for trace metals, especially copper (Cu).On the other hand, the pH of the solution play a critical role towards NPs-Fe interactions. Depending on the pH, the surface charge of the particles are modified and hence pH is involved in the electrostatic forces that drive the particles aggregation state and contribute to metal adsorption. The second part of the study is focused on the interactions occurring with IONPs in presence of plants. Several experiments are conducted in aqueous solution and in soil columns to precise the impacts of IONPs on the growth medium and to assess the effects of IONPs on plants. Results (magnetic susceptibility) show that IONPs manage to penetrate the roots of beans and sunflower plants (57 and 63 days-old) and that they are translocated to the aerial parts in low amounts. Plants respond to IONPs penetration by increasing the plant biomass and the chlorophyll contents and by decreasing the lipid peroxidation.

Cette thèse a porté sur la détermination et l’étude écodynamique d’éléments traces métalliques sur des technosols fortement contaminés en métaux et metalloïdes en contexte de revégétalisation naturelle ou de phytoremédiation. Deux schémas d'extractions séquentielles ont été utilisés conjointement à des extractions sélectives en parallèle avec la détermination de la concentration totale dans les sols, de la concentration totale dissoute dans les eaux porales, du pool labile (sondes DGT) et des tests de germination avec des haricots nains pour étudier la spéciation, la mobilité et la phytodisponibilité de métaux et métalloïdes (Zn, Pb, Cd, As et Sb) pour les technosols de deux sites post-minier (La Petite Faye) et industriel (Mortagne-du-Nord). De plus de jeunes plants de P. euramericana Dorskamp ont été cultivés en rhizobox sur les technosols de Mortagne-du-Nord pour étudier l’effet rhizosphèrique sur la mobilité des métaux. Enfin l’effet de l’addition d’azote sous forme de nitrate et d’ammonium sur le comportement de ces métaux a été également étudié pour P. euramericana Dorskamp sur ces mêmes sols. Malgré les fortes concentrations totales en métaux et métalloïdes dans les sols du site de La Petite Faye, la mobilité de ces éléments potentiellement toxiques est limitée car associés à la fraction résiduelle. La phytodisponibilité est également limitée et corrélée avec le pool labile des technosols. La culture de P. euramericana Dorskamp a généré un effet rhizosphèrique caractérisé par une augmentation de la valeur du pH et la concentration de carbone organique dissout (COD) de la solution de sol ainsi qu’une diminution des concentrations totale dissoute des métaux (Zn, Pb et Cd) dans la solution de sol. L’addition d’azote sous forme de nitrate et d’ammonium a respectivement augmenté et diminué le pH de la solution de sol et dans le cas de l’ammonium a augmenté également le COD et stabilisé les métaux dans la rhizosphère par rapport aux sols de contrôle. / This thesis dealt with the determination and study of the ecodynamics of trace metals in technosols highly contaminated in metals and metalloids in the context of natural revegetalisation or phytoremediation. Two sequential extraction schemes were used jointly with selective extractions in parallel with the determination of the total metals concentration in soils, the total dissolved metals concentration in the soil pore water, the metals labile pool (DGT) and germination tests with dwarf beans to investigate the speciation, mobility and phytoavailability of (Zn, Pb, Cd, As and Sb) for technosols of two post-mining (La Petite Faye) and industrial (Mortagne du Nord) sites. Additionally, young plants of P. euramericana Dorskamp were cultivated in rhizobox on Mortagne du Nord technosols to investigate the rhizospheric effect on the mobility of metals. Moreover, the effect of nitrogen addition under nitrate and ammonium on the behavior of these metals has been investigated for P. euramericana Dorskamp for the same soils. Despite the high total metals and metalloids concentration in the La Petite Faye soils, the mobility of these potentially toxic elements is limited because of their association with the residual fraction. The phytoavailability is also limited and correlated with the labile pool of technosols. The culture of P. euramericana Dorskamp generated a rhizospheric effect characterized by an increase of the pH and concentration of dissolved organic carbon (DOC) in the soil pore water and a decrease in the total dissolved concentration of metals (Zn, Pb et Cd) in the soil pore water. The addition of nitrogen under nitrate or ammonium respectively increased and decreased the soil pore water pH and in the case of ammonium the DOC also increased and stabilized metals in the rhizosphere in comparison to control soils.

O presente estudo analisou aspectos do ciclo de vida e níveis de metais em Atherinella brasiliensis da praia de Itamambuca, Ubatuba (SP). As coletas foram mensais, nos períodos diurno e noturno, de setembro de 2003 a fevereiro de 2005, em quatro estações na praia e uma no rio Itamambuca, utilizando-se picaré. Os indivíduos migram diariamente para dentro do rio no período noturno. O melhor ajuste ao modelo de von Bertalanffy (CT= 164,85*(1-e-2,16(t+0,0038))) e à longevidade (A0,95= 1,378 ano) foi obtido pelo método de Ford-Walford. O índice de performance de crescimento e a mortalidade variaram de 2,77 a 2,91 e 1,64 a 1,82 ano-1, respectivamente. O valor de L50 estimado para sexos agrupados foi 86,6 mm, e os de RGS, DK e a freqüência de desovantes sugerem desova durante todo o ano, com maior intensidade do final da primavera até início do outono. A desova é parcelada, com alta freqüência e em pequenos lotes. Altas concentrações de Cr, Fe e Zn foram detectadas na musculatura, sendo maiores em indivíduos jovens e na alta temporada turística. Pode-se concluir que o peixe-rei passa todo seu ciclo de vida na praia de Itamambuca, apresenta altas taxas de crescimento e mortalidade natural, e desova ao longo de todo o ano. / The present study analyzed the life history and metal levels of Atherinella brasiliensis from Itamambuca beach, Ubatuba (SP). Surveys were conducted monthly, in diurnal and nocturnal periods, between September 2003 and February 2005, in four stations at the beach and one at the Itamambuca river, using beach seine. Individuals showed daily migration into the river at nocturnal period. The better adjustment to von Bertalanffy?s model (Lt = 164.85*(1-e-2.16(t+0.0038))) and to longevity (A0.95= 1.378 year) was obtained through Ford-Walford method. The value of estimated L50 for grouped gender was 86.6 mm, and the GSR, the DK and the spawning frequency suggest spawning during all year around, with higher intensity in late spring until middle autumn. The high frequency of spawning and the low batch fecundity indicate that the species is a batch spawner. High concentrations of Cr, Fe and Zn were detected in musculature, being higher among young individuals, and during tourist high season. In conclusion, the Brazilian silverside spends its life cycle on the Itamambuca beach, shows high growth and natural mortality rates, and spawning throughout the year.

Made available in DSpace on 2015-04-22T22:02:12Z (GMT). No. of bitstreams: 1 Paulo Renan.pdf: 1587343 bytes, checksum: 5a08e797bff6ad2f7e370d3d94651720 (MD5) Previous issue date: 2012-08-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Fractionation of the metals Fe, Mn, Zn, Cu and Ni in sediments was performed for samples collected from ten locations from igarapé Educandos sub-basin, in Manaus AM, north Brazil. From air dried sediment particles was made a sequential extraction procedure proposed by the European Community Bureau of Reference (BCR). In general, the speciation study revealed that Mn, Zn, Cu and Ni have high mobility due to their high contents in the exchangeable/acid soluble fraction, while Fe is less mobile. Principal component analysis (PCA) clearly separated the metals in groups, due to different distributions of the metals in the various fractions, in sediments from different locations. The enrichment factor (EF) obtained for each metal showed the intense anthropogenic influence in the region. Based on the risk assessment code (RAC), Mn, Zn and Ni posed a very high risk to the ecosystem (RAC > 50%), Cu pose a high risk (RAC > 31%) and Fe a low risk (RAC < 10%). / O fracionamento dos metais Fe, Mn, Zn, Cu e Ni em sedimentos de fundo foi realizado para amostras coletadas de dez locais na sub-bacia do igarapé Educandos, na cidade de Manaus Brasil. Nas partículas de sedimento seco ao ar, foi feito um procedimento de extração sequencial proposto pela European Community Bureau of Reference (BCR). De maneira geral, o estudo de especiação revelou que Mn, Zn, Cu e Ni possuem alta mobilidade devido aos seus altos conteúdos na fração solúvel em ácido/trocável, enquanto que Fe é o menos móvel. A análise de componentes principais (PCA) aplicada para as diferentes frações do procedimento BCR claramente separou os metais dentro de grupos, devido as diferentes distribuições dos metais nas várias frações. O fator de enriquecimento (FE) obtido para cada metal mostrou a intensa influência antrópica na região. Baseado no código de avaliação de risco (RAC), Mn, Zn e Ni representam um risco muito alto para este ecossistema (RAC > 50%), Cu representa um risco alto (RAC > 31%) e Fe um risco baixo (RAC < 10%).

L’étude réalisée lors de ce travail de thèse porte sur l’évaluation de l'impact de l’agglomération Marseillaise sur le milieu côtier à travers la quantification des éléments traces métalliques (ETM) et du carbone organique. Sur le littoral méditerranéen français, Marseille représente la plus grande agglomération (~ 1.7M Ha) et possède la station d’épuration (STEP) enterrée la plus grande d’Europe (capacité de 1.62M équivalent-habitants), avec une façade directement ouverte sur la Méditerranée. L’impact de cette zone urbaine et industrialisée (flux brut) sur la zone côtière reste mal compris, de par la multiplicité des sources (apports directs(rivières/effluents) vs. apports diffus (friches industrielles côtières, aérosols, ...)) en partie contrôlée par le climat. Il en est de même des mécanismes de transfert des contaminants conditionnant leur devenir dans le milieu marin (flux nets vers le large). Dans ce contexte, différentes campagnes de prélèvements d’eau et de sédiments ont été mises en oeuvre sous des conditions climatiques contrastées (temps sec vs. pluie) dans les rivières ainsi qu'en mer, le long d’un transect allant de la côte à plus de 2 km au large des rejets. Les objectifs de cette étude visaient à déterminer les sources de contaminants au milieu côtier et à comprendre leurs mécanismes de transfert et leur devenir en mer. Par temps sec, les résultats obtenus ont montré que la dynamique du système est principalement contrôlée par les rejets de la STEP qui, par exemple, est responsable à plus de 75% des apports en Ag, Cu ou Pb au milieu côtier. Une fois en mer, les différents ETM analysés présentent un profil non conservatif, dû à un fractionnement dissous/particulaire hors équilibre dans les émissaires associé à un relargage rapide au début du gradient de salinité. Ces résultats ont été confirmés par une expérience de remobilisation réalisée au laboratoire permettant de mieux comprendre la cinétique de désorption des ETM. Dans ces conditions, il a été démontré qu'il était indispensable de filtrersur le terrain les échantillons pour ne pas sous-estimer la fraction dissoute des ETM. Par temps de pluie, le suivi des apports au cours d'une crue a montré la très grande réactivité du système, typique de rivières côtières. La majorité des ETM, transportés principalement sous forme particulaire, subissent une fois en mer des processus de désorption avec des cinétiques plus lentes et à des salinités plus importantes que par temps sec. Ces différences sont probablement liées à la nature des particules, urbaines et très organiques par temps sec, plutôt terrigène et inorganiques par temps de pluie. Enfin, une expérience de vitesse de chute des particules transitant dans le système par temps sec et de pluie a été développée au laboratoire. Elle a permis de caractériser les particules étudiées par des paramètres physico-chimiques intégrables au modèle hydro-sédimentaire de l'IFREMER, permettant de mieux évaluer le devenir des particules en zone côtière. / The aim of this PhD was to evaluate the impact from Marseille agglomeration on thecoastal area, using trace metals and organic carbon quantification. On the French Mediterraneancoast, Marseille is the largest agglomeration (~1.7M inhabitants), located directly on coast andhave the biggest European underground wastewater treatment plan (WWTP, 1.62M eq). Theimpact of this urbanized and industrialized area on the coastal zone (bulk fluxes) remainsmisunderstood, because of the multiplicity of contaminant sources (direct inputs(rivers/effluents) vs. diffusive ones (coastal industrial wasteland, aerosols, …)) partlycontrolled by climatic conditions. Similarly, the transfer mechanisms of contaminants thatcontrol their fate to the open sea (net fluxes) have to be studied. In such context, numerouswater and sediment sampling campaigns were performed during contrasted climatic conditions(baseflow vs. flood) in the tributaries and along a 2km coastal-offshore transect in front of theoutputs. The main objectives of this study were to determine contaminants sources, transfermechanisms and fate in the coastal zone. During baseflow conditions, results have shown thatthe system dynamic is mainly controlled by the WWTP inputs, that are for instance the maincontributor (>75%) of Ag, Cu or Pb inputs to the coastal area. When discharged to the sea, thestudied trace metals presented non-conservative behaviours, consecutive to adissolved/particulate fractionation out of equilibrium in the outlets associated to fastremobilization at the beginning of the salinity gradient. These results were confirmed by labremobilization experiments allowing to better understand the desorption kinetics of tracemetals. Under such conditions, it was demonstrated that on-field filtration is a prerequisite toavoid under-estimation of the dissolved fraction of trace metals. The monitoring of a flood eventduring a rainy period has shown the high reactivity of the studied system, a peculiarity ofMediterraneean coastal rivers. Most of the studied trace metals, mainly brought in theparticulate fraction, suffer desorption processes when discharged to the sea, a processcharacterized by kinetics slower and effective at higher salinity in comparison to baseflowinputs. These differences are most probably linked to the nature of particles being urban andorganic during baseflow, mostly terrigeneous and inorganic during flood. Finally, a settling rateexperiment was designed in the lab in order to evaluate the physical and chemical characteristicsof representative particles. The obtained parameters were integrated in the 3D hydrodynamicand sediment transport model of IFREMER allowing to better evaluate the fate of pollutedparticles in the coastal area.

Les éléments chimiques métalliques tels que Fe, Cu ou Zn sont présents en quantité infime dans le cerveau. Le rôle de ces métaux traces dans les fonctions neuronales, telles que la transmission synaptique et les processus de mémorisation, reste encore largement à élucider. En outre, une dyshoméostasie des métaux est retrouvée dans de nombreuses neuropathologies, telles que maladie d’Alzheimer, de Parkinson ou sclérose latérale amyotrophique. Les mécanismes d’interaction des métaux traces au niveau neuronal sont difficiles à décrire faute de méthodes analytiques possédant une résolution et une sensibilité adaptées pour en déterminer la distribution à l’échelle synaptique. La spectrométrie de fluorescence-X synchrotron (SXRF) est une méthode d’analyse chimique multi-élémentaire permettant de décrire la distribution quantitative de ces éléments à l’échelle subcellulaire avec une résolution nanométrique (40 nm avec la ligne ID16A du synchrotron ESRF) et une très haute sensibilité. Afin d’interpréter avec précision les résultats d’imagerie chimique, nous avons développé un protocole pour corréler l’imagerie nano-SXRF avec la microscopie super résolutive de déplétion par émission stimulée (STED) permettant ainsi la corrélation des distributions des métaux avec celle de protéines cibles en super résolution. Nous avons marqué les microtubules et l’actine-F de neurones primaires d’hippocampe de rat puis imagé le cytosquelette par microscopie STED avant de déterminer par spectrométrie SXRF les distributions des éléments P, S, Fe, Cu et Zn. Nous avons ainsi mis en évidence la colocalisation du Zn et des microtubules au niveau dendritique ainsi qu’une localisation du Cu essentiellement dans le cou des épines dendritiques riches en F-actine, et une distribution du Fe sous forme de points très localisés dans les dendrites. Ces résultats ont révélé le rôle essentiel du Zn dans l’architecture du cytosquelette des neurones d’hippocampe et la méthode d’imagerie corrélative développée ouvre de nouvelles perspectives pour l’étude des dyshoméostasies des métaux dans les maladies neurodégénératives. / Metallic chemical elements such as Fe, Cu or Zn are present in minute quantities in the brain. The role of these trace metals in neuronal functions such as synaptic transmission and memory processes remains largely unclear. Moreover, metal dyshomeostasis is found in many neuropathologies, such as Alzheimer’s disease, Parkinson’s or amyotrophic lateral sclerosis. The interaction mechanisms of trace metals at the neuronal level are difficult to describe because of the lack of analytical methods with appropriate resolution and sensitivity to determine metal distribution at the synaptic level. Synchrotron X-ray fluorescence spectrometry (SXRF) is a multielemental chemical analysis method for describing the quantitative distribution of these elements at the sub-cellular scale with a nanometric resolution (40 nm at ESRF beamline ID16A ) and a very high sensitivity. In order to accurately interpret chemical imaging results, we have developed a protocol to correlate nano-SXRF imaging with stimulated emission depletion super resolution microscopy (STED), allowing the correlation of metal distribution and that of target proteins in super resolution. We labeled microtubules and F-actin of primary rat hippocampal neurons and imaged the cytoskeleton by STED microscopy before determining the distributions of P, S, Fe, Cu and Zn by SXRF spectrometry. We evidenced the colocalization of Zn and microtubules at the dendritic level and a localization of Cu mainly in the neck of dendritic spines rich in F-actin, and a distribution of Fe in the form of very localized points in the dendrites. These results highlight the crucial role of Zn in cytoskeleton architecture of hippocampal neurons and the developed correlative imaging method opens new perspectives for the study of metal dyshomeostasis in neurodegenerative diseases.

The recently developed technique of diffusive gradients in thin films (DGT) for speciation measurement of analytes in the environment was further developed through the development of series of new binding phases including poly(acrylamide-co-acrylic acid) copolymer hydrogel (PAM-PAA), poly(acrylamidoglycolic acid-co-acrylamide) (PAAGA-PAM) hydrogel, the Whatman P81 cellulose phosphate ion exchange membrane (P81) and a liquid binding phase of poly(4-styrenesulfonate) (PSS). A new diffusion layer, cellulose dialysis membrane, was also employed for the liquid binding phase DGT. PAM-PAA copolymer hydrogel was prepared by the controlled hydrolysis of polyacrylamide (PAM) in an alkaline solution of 10% sodium hydroxide. The capacity of the copolymer hydrogel to bind various metal ions was tested under a range of uptake conditions. Ions such as Cu2+ and Cd2+ were bound more strongly to the copolymer hydrogel than the competing ions such as Na+, K+, Ca2+ and Mg2+. Metals bound to the copolymer hydrogel can be efficiently eluted in 2 M HNO3 solution (>94%). Application of this new binding material to DGT technique was validated in a synthetic lake water (Windermere, Lake District, UK) with a recovery of 99.0% for Cu2+. PAAGA-PAM hydrogel was prepared by copolymerising 2-acrylamidoglycolic acid with acrylamide. The metal ion binding properties of the hydrogel were characterised for Cu2+, Cd2+ and competing ions under various experimental conditions. The hydrogel was shown to bind Cu2+ and Cd2+ strongly under non-competitive binding conditions, with binding capacities of 5.3 and 5.1 micromol cm-2, respectively. The binding capacity of each metal decreased, under competitive binding conditions (with a range of metal ions present at 17.8 mN), to 1.3 and 0.17 micromol cm-2, respectively, indicating a strong selective binding towards Cu2+. The metal ions were readily recovered (>94%) by eluting with 2 M HNO3. Finally, the copolymer hydrogel was tested as a binding phase with the DGT technique. A linear mass vs. time relationship was observed for Cu2+ in Windermere water with a recovery of close to 100%. The use of a commercially available solid ion exchange membrane (P81) as the binding phase in DGT analysis was demonstrated. P81 is a strong cation exchange membrane. Its performance characteristics as a new binding phase in DGT measurement of Cu2+ and Cd2+ were systematically investigated. Several advantages over the conventional ion exchange resin-embedded hydrogel based binding phases used in DGT were observed. These include: simple preparation, ease of handling, and reusability. The binding phase preferentially binds to transition metal ions rather than competing ions. Within the optimum pH range (pH 4.0 - 9.0), the maximum non-competitive binding capacities of the membrane for Cu2+ and Cd2+ were 3.22 and 3.07 micromol cm-2, respectively. The suitability of the new membrane-based binding phase for DGT applications was validated experimentally. The results demonstrated excellent agreement with theoretically predicted trends. The reusability of this binding phase was also investigated. Application of a liquid binding phase and a dialysis membrane diffusive layer were proposed for the first time. The binding phase was a 0.020 M solution of poly(4-styrenesulfonate) (PSS) polyelectrolyte using a specially designed DGT device. The binding properties of Cd2+, Cu2+, and a range of alkali and alkaline earth metal ions to the PSS solution were characterised. The PSS behaved like a cation exchanger with preferential binding to Cd2+ (6.0 micromole ml-1, log K = 9.0) and Cu2+ (2.5 micromole ml-1, log K = 8.1) under competitive binding conditions. The DGT devices were successfully validated for Cd2+ and Cu2+ in Windermere water. The speciation performance of the solid and liquid binding phases developed in this study was investigated in solutions containing ethylenediaminetetraacetic acid disodium salt (EDTA), humic acid (HA), glucose (GL), dodecylbenzenesulfonic acid (DBS) and tannic acid (TA) with Cu2+ and Cd2+. The ratios of labile metals over total metals were at good agreement with calculated theoretical values using Stability Constants Database. The results indicated that the DGT-labile concentration measured by DGT with these binding phases is essentially free metal ion concentration in the sample. All newly developed DGT binding phases were successfully applied for environmental speciation. The field deployments were carried out in both freshwater and salt-water test sites.

This thesis focussed on the effects of a range of trace metals on various stages of Haliotis rubra development. The trace metals assessed in this thesis were the essential metals Cu, Zn and Fe; and, the non-essential metals Hg, Cd and Pb. Copper and Hg proved to be the two most toxic metals to the life stages of H. rubra studied. The concentrations affecting normal development of the fertilised egg exposed for 48h showed a decreasing order of toxicity with 48hEC50 recorded at 7µg Cu/L, 20µg Hg/L, 42µg Zn/L, 4,102µg Fe/L, 4,515µg Cd/L, and 5,111µg Pb/L. Settlement and metamorphosis occur in normal larvae when aged 5 days, and exposure of the 5 day old larvae to the metals for 48h resulted in impaired crawling success at 128µg/L Cu and Hg, and 1250µg Cd/L. Settlement was inhibited after exposure to 128µg Cu/L, 32µg Hg/L, and 1250 Cd/L. Metamorphosis of larvae 96h after exposure was inhibited by 32µg Cu/L, 512µg Zn/L, 32µg Hg/L and 625µg Cd/L. The rate of meta morphosis was enhanced after exposure to Cu and Hg at 0.5µg/L and 64 - 256µg Zn/L. Exposure to Zn at concentrations 64, 128 and 256 µg Zn/L caused an increased rate of settlement and metamorphosis. Juvenile H. rubra exposed to the six metals for 96h were most sensitive to Cu, which produced a 96hLC50 of 87µg Cu/L compared to Hg with a 96hLC50 of 173µg Hg/L. Juvenile H. rubra were relatively insensitive to Zn and Cd with the 96h LC50 of 1730µg Zn/L and 3700µg Cd/L, respectively. Exposure to individual solutions of Cu, Zn, and Cd for 28 days resulted in juvenile H. rubra bioaccumulating significant concentrations of metals in the visceramantleedible foot muscle. Accumulation of Hg was greater in the mantle-viscera-edible foot muscle. Following exposure, depuration in clean seawater for 28 days produced varying decreases in metal concentrations for each tissue compartment. Sodium-potassium activated ATPase (Na+,K+-ATPase) activity in the gills of juvenile H. rubra was significantly affected following expos ure to the trace metals for 28 days, with a decreasing order of effect on enzyme activity of Hg-Cu-Cd-Zn. Depuration of H. rubra in clean seawater for 28 days resulted in the recovery of Na+,K+-ATPase activity to varying degrees. The recovery of ATPase activity was more efficient following exposure to Cd-Zn-Cu-Hg. The overall results of this thesis provide initial baseline information to evaluate the sensitivity of H. rubra to trace metal toxicants, and these results may be utilised by regulators for establishing marine water quality guidelines to protect H. rubra and other abalone species in their natural habitats.

Volatile heavy metals are liberated from magmas during eruptive and passively degassing volcanic activity. Volcanic emanations have been estimated to contribute 20-40% of volatile elements such as Bi, Pb, As or Sb, and up to 40-50 % of Cd and Hg annually (Nriagu, 1989). Some workers, however, believe these ranges are too high (Hinkley, 1999) or too low (Zreda-Gostynska and Kyle, 1997) leading to considerable differences in global inventory budgets of these metals and the degree to which they load the atmosphere. The objective of this work is to investigate the behavior of volatile heavy metals such as Au, Tl, As, Pb etc. in subaerially erupted magmas and experimentally in silicate melts. Analysis of natural pumice samples confirm the futile, sporadic nature of Hg and associated heavy metals, suggesting these metals are fully degassed prior to deposition. Diffusion experiments were conducted in natural basalt, dacite and synthetic rhyolite (Ab-Or-Qz minimum eutectic) over a range of temperatures (1200 – 1430 °C) at 0.1 MPa. Starting compositions were doped with a heavy metal cocktail (Bi, Pb, Tl, Au, Re, Sb, Sn, Cd, Mo, As, Cu) and loaded into open top Pt capsules. One set of experiments examined the effect of melt composition (polymerization) on element diffusion, and the second investigated the effects of ligands on diffusion by adding known concentrations of Cl and S. During experiments of varying duration, concentration gradients arose in the volatile trace metals due to their varying volatility, as measured (normal to the melt/gas interface) by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) in quenched glasses. Diffusion profiles followed an Arrhenius relationship from which diffusion coefficients (D) and activation energies (Ea) were obtained for Au, Tl, As, Cd, Re, Pb and Bi (in decreasing order of volatility). Results show Au and Tl are the most volatile in dacite and rhyolite yielding LogDDac Au = -10.7 ± 0.1 m2/s and LogDDac Tl = -10.9 ± 0.1 m2/s in dacite, and LogDRhy Au = -10.9 ± 0.1 m2/s and LogDRhy Tl = -11.3 ± 0.3 m2/s in rhyolite respectively. The D for Au could not be measured in basalt but Tl was the fastest diffusing species LogDBas Tl = -10.8 ± 0.2 m2/s. Ligands Cl and S were shown to increase the volatilities of all metals, with S having a more profound effect. Diffusivities were applied to a simple 1D bubble growth model (Smith 1955). Model results indicate diffusion coefficients play a major role in metal fractionation processes occurring at depths that ultimately dictate what metal ratios are measured at the surface of volcanoes.

Here we report vertical profiles of dissolved (0.2 um filtered) Aluminum (Al) for eight stations in the Beaufort Sea in the Canadian Arctic, six of which are along a transect extending from the coastal shelf northeast of the Mackenzie River delta out to the Beaufort Sea. Sampling was performed aboard the CCGS Sir Wilfrid Laurier in September 2007 and all analyses were performed in a Class 100 clean space at the University of Victoria. Vertical profiles of dissolved Al in the water column displayed surface maxima, subsurface minima and a general increase in concentration with depth as is characteristic of a “scavenged” trace element in seawater. Concentrations of dissolved Al for the upper 1000 m were generally low ranging from the < 1 nmol kg-1 observed in the sub-surface minimum corresponding to the Pacific inflow layer and increasing to ~6-10 nmol kg-1 with depth. The surface maxima at stations for Al was associated with relatively fresh surface water (26-30 PSS) that is believed to be the result of seasonal sea-ice melt. This correlation suggests that the melting of sea-ice with entrained sediments may be an important mechanism for the delivery of Al and associated trace metals to the water column of the Beaufort Sea. We also report measurements of “total Al” (unfiltered and acidified to pH 1.7 for two year prior to analysis) for the Arctic Ocean which indicate that a significant proportion of Al in the water column is present in the > 0.2 um fraction. These measurements and the hydrographic data along the transect indicate the transport of a cold, saline, metal enriched water mass off of the continental shelf into the Canada Basin. This water mass appears to reflect the return of cold, high salinity slope water originally emplaced on the shelf by upwelling favourable winds. Alternatively, this water mass may be the product of brine exclusion from sea-ice formation during the previous winter that was unable to vacate the shelf due to the persistent upwelling observed throughout 2007. This finding suggests that the convection of cold, dense shelf water may be a mechanism for supplying the deep waters of the Arctic with an injection of water containing a significant Al content. In addition, a low volume sequential injection analysis (SIA) method is proposed for determination of elevated concentrations of Al, like those typically observed in coastal and river waters. A thorough optimization of the chemistry and instrumental parameters was performed along with an extensive investigation into potential interferents. The method was found to be largely free of interferents at environmentally relevant concentrations and was determined to have a detection limit of 24 nM. The precision of the method was reported to be 2% at 75 nmol kg-1 and analysis of the SLRS-4 certified reference material validated the accuracy of the method. Analysis of several samples that were previously analyzed via flow injection analysis (FIA) and standardized with consensus values of an open ocean reference material indicated the method returned comparable values for the Al concentration in the samples. Development and optimization of the SIA has resulted in an accurate and precise low-cost method of analysis that is both sensitive and relatively free from interference for the detection of nano-molar levels of Al in coastal and natural waters.