No description available.

No description available.

Four life stages of freshwater mussels were tested for their sensitivity to copper and a metal-containing effluent. This permitted an assessment of the variability in sensitivity among the life stages in order to identify those stages most threatened in the wild from copper exposure. Glochidia, while held within the marsupia of the adult, the released or isolated glochidia, the encysted glochidia, and the gravid mussel were tested. Little effect on glochidia was detected following 30- day artificial stream exposures of gravid adults to 19.1 ug Cu/L and an effluent containing an average of 23.9 ug Cu/L. Isolated glochidia were killed by copper concentrations ranging from 20-80 ug/L in 24-hour exposures, with sensitivity increasing with hardness and temperature. Encysted glochidia were resistant to exposures up to 400 ug Cu/L. No significant effect on metamorphosis to the stage was detected. This is likely due to the encapsulation of the glochidium by the host fish. Juvenile mussels reduced their activity during 24-hour exposures to copper concentrations as low as 17 to 24 ug/L and concentrations of 30 to 42 ug/L caused mortality. Juvenile mussels and glochidia within the marsupia are probably the two most sensitive stages in the life cycle of the freshwater mussel. Copper pollution will have its greatest impact in the summer, during periods of high water temperature and low flow. / Master of Science

Mercury (Hg) is a toxicant of global concern, but few strategies exist to evaluate its biological effects on the ecosystem. Piscivorous wildlife, such as mink (Mustela vison), are particularly at risk because they can bioaccumulate Hg to concentrations known to impair neurological systems. Given that biochemical changes in the brain precede functional and structural impairments, I evaluated the use of neurochemicals as early-warning biomarkers of Hg toxicity in mink. Initial studies demonstrated that neurochemical biomarkers could be measured from mink carcasses collected from the field, as long as factors such as storage temperature and freeze thaw cycles were accounted for. To determine if Hg could directly impair neurochemicals in mink, an in vitro study demonstrated that Hg (HgCl2 and MeHg) could inhibit radioligand binding to the muscarinic cholinergic (mACh) receptor in the cerebellum and cerebral cortex regions of the brain. By analyzing whole brains collected from wild mink, it was demonstrated that a significant positive correlation existed between concentrations of brain Hg and levels of mACh receptors. These field observations were confirmed by results from a controlled methyl Hg (MeHg) feeding trial in captive mink, whereby sub-chronic exposure of mink to 0.5 - 2 ppm MeHg (ecologically relevant levels) resulted in significant increases in acetylcholinesterase activity and mACh receptor levels in specific brain regions. Collectively, these results demonstrated that exposure of mink to environmentally realistic concentrations of Hg can be related to alterations in neurochemicals at multiple tiers of biological organization. Given the importance of a functional nervous system in wildlife health, the physiological and ecological significance of these findings need further exploration. The results demonstrate that neurochemical approaches may be novel biomarkers to assess the ecotoxicology of Hg, and by extension, other pollutants o

Les hôpitaux génèrent des effluents riches en résidus pharmaceutiques (RP), fonctions de leurs activités de soins et de diagnostic. Certains de ces RP sont aujourd’hui retrouvés de manière ubiquitaire dans les écosystèmes aquatiques, en raison de leurs propriétés persistantes et/ou de leur émission continue. La variété de ces RP est telle qu’il est nécessaire de les hiérarchiser, en fonction des risques qu’ils représentent pour l’Environnement, à des fins d’étude et de gestion. Un de ces risques est le transfert des RP bioaccumulables (i.e. Kow élevé et faible biodégradabilité) dans les chaînes alimentaires, via les processus de bioconcentration, de bioaccumulation et de bioamplification. L’objectif principal de cette thèse est de caractériser expérimentalement la bioconcentration et la bioaccumulation de molécules identifiées comme prioritaires dans des travaux précédents. Le composé modèle que nous avons choisi est le tamoxifen, molécule utilisée contre le cancer du sein et déjà retrouvé dans l’Environnement. Les organismes étudiés, issus des trois niveaux trophiques de la chaine alimentaire modèle, sont Pseudokirchneriella subcapitata, Daphnia magna et Danio rerio. Pour mesurer la teneur de cette molécule dans les organismes, nous avons développé une méthode d’analyse reposant sur l’utilisation d’une molécule marquée par un isotope stable, le 15N tamoxifen.Nous avons mesuré des facteurs de bioconcentration (BCF) allant de 12800 chez D. magna à 85600 dans le foie de D. rerio en passant par 21500 chez P. subcapitata. Chez ces derniers, nous avons également évalué la part du régime alimentaire dans la bioaccumulation du tamoxifen. Nous avons observé que plus la concentration dans le milieu d’exposition est faible, plus le régime alimentaire contribue à la bioaccumulation. Ces travaux de thèse présentent de nombreuses perspectives que l’on peut regrouper autour de deux axes : connaissance de l’écotoxicité des RP et de l’écotoxicologie isotopique. / Hospitals generates effluents rich in pharmaceuticals compounds (PC), notably because of careand diagnostics activities. Some of these PCs are ubiquitous in aquatic ecosystems owing to itspersistent properties and/or because of continuous releasing in environment. The diversity of thesePCs is so strong that it is necessary to prioritize them, considering risks that PCs represents forthe Environment, in order to manage and study these compounds. One of these risks is the transferof bioaccumulatives PCs (i.e. PCs with high Kow and low biodegradability) along trophic webs,via bioconcentration, bioaccumulation and biomagnification processes. The main objective of thisthesis is to characterize bioconcentration and bioaccumulation of molecules identified as priorityin previous studies. The model compound choose in our work is the tamoxifen, a molecule usedin the treatment of breast cancer and already found in Environment. Organisms studied, typicalfrom three trophic levels of the model trophic chain, are Pseudokirchneriella subcapitata, Daphniamagna and Danio rerio. In order to measure content of tamoxifen in organisms, we developed aninnovative analytic method based on the use of stable isotopes labelled tamoxifen : 15N tamoxifen.We succeeded to measure bioconcentration factors (BCF) from 12800 in D. magna to 85600 in liverof D. rerio including BCF of 21500 in P. subcapitata. In this latter, we also assessed the contributionof dietary route to the total contamination of D. magna by tamoxifen. We observed that the morethe medium concentration was weak, the more the dietary route contribute to the contamination.These works shows numerous perspectives that we can gather inside two axes : ecotoxicity knowledgeof PCs an isotopic ecotoxicology.

Les éléments traces (ET) se trouvent naturellement dans l’environnement. Ces dernières années, des apports croissants en ET sont induits par des activités anthropiques, causant des problèmes environnementaux surtout dans le milieu marin. Certains ET sont toxiques et le besoin de méthodes fiables pour leur analyse dans des échantillons environnementaux est indéniable. À travers cette thèse, des méthodes analytiques ont été développées et validées pour l’analyse des ET dans les sédiments et les organismes marins par spectrométrie d’absorption atomique à source continu, haute résolution et introduction solide directe (SS-HR-CS-AAS). Des études environnementales basées sur l’utilisation de cette méthode et d’autres ont été réalisés. Une première étude a été réalisée sur des sédiments (de surface et carottes) collectés en Namibie. Cette thèse présente une série inédite de concentrations de base sur la côte namibienne. Une contamination importante en Pb, Cu, Zn et Cd a été démontrée autour des zones les plus peuplées. Les pollutions au Pb et leurs sources ont été étudiées grâce aux rapports isotopiques du Pb. Une deuxième étude a été réalisée sur différentes espèces d’éponges marines et des sédiments collectés en France et en Irlande. Il est montré que les éponges accumulent plus les ET que les sédiments et de façon différente selon les espèces. Des analyses de spéciation de l’arsenic ont été réalisées sur les éponges par chromatographie liquide haute performance couplée à un ICP-MS. Les résultats ont montré une bioaccumulation très importante de ce métalloïde dans les éponges et sa biotransformation des formes inorganiques en formes organiques beaucoup moins toxiques. / Trace elements (TE) naturally occur in the environment but their inputs have been increasing by anthropogenic activities in the last decades, causing environmental concerns, particularly in coastal ecosystems. TE are toxic and the need of reliable methods for their determination in environmental samples is undeniable. The first part of this PhD was focused on the development and full validation of methods for the analysis of TE in sediments and marine organisms by Solid Sampling High Resolution Continuum Source Atomic Absorption Spectrometry (SSHR-CS-AAS). Second, environmental studies based on these and others methodologies were then performed. A first monitoring survey was performed on sediments (surface and core samples) collected along the Namibian coast. This thesis provides the first baseline of TE contents and historical record of pollution in the area. Significant Pb, Cu, Cd and Zn enrichments were highlighted around the most populated areas, providing a needed baseline for present and future evaluation of the Namibian marine environment. Pb pollutions and their sources were also tracked through the use of Pb isotope ratios. A second monitoring survey was performed on different marine sponges and sediments collected in the French Mediterranean and in the Irish coasts. This work showed that sponges accumulate more TE than sediments in different extents according to species. Arsenic speciation analysis was performed in sponges by High Performance Liquid Chromatography (HPLC) coupled with ICP-MS. This special focus on arsenic highlighted the great bioaccumulation of this metalloid in sponges and its biotransformation from inorganic forms to less toxic organic forms.

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Environmental toxicologists and public health officials are responsible for assisting in the identification, management, and mitigation of public health hazards. As a result, there is a continued need for robust analytical tools that can aid in the rapid quantification and characterization of chemical exposure. In the first research phase, we demonstrated that a current tool for estimating human organophosphate pesticide exposure, measuring dialkyl phosphate (DAPs) metabolites in urine as chemical biomarkers of pesticide exposure, could represent exposure to DAPs themselves and not to pesticides. We showed that DAPs are metabolically stable, have high oral bioavailability, and are rapidly excreted in the urine following oral exposure. Results suggest that DAP measurements may lead to overestimates of human organophosphate pesticide exposure. In the second phase of research, a quick, easy, cheap, effective, rugged, and safe (QuEChERS) based analytical method was developed and validated for quantifying polycyclic aromatic hydrocarbons (PAHs) in biotic matrices with fat contents that ranged from 3 to 11%. Our method improved PAH recoveries 50 to 200% compared to traditional QuEChERS methods, performed as well or better than state of the art Soxhlet and accelerated solvent extraction methods, had sensitivity useful for chemical exposure assessments, and reduced sample preparation costs by 10 fold. The validated QuEChERS method was subsequently employed in a human exposure assessment. Little is known about how traditional Native American fish smoke-preserving methods impact PAH loads in smoked foods, Tribal PAH exposure, or health risks. Differences in smoked salmon PAH loads were not observed between Tribal smoking methods, where smoking methods were controlled for smoking structure and smoke source. PAH loads in Tribally smoked fish were up to 430 times greater than those measured in commercially available smoked fish. It is not likely that dietary exposure to non-carcinogenic PAHs at heritage ingestion rates of 300 grams per day poses an appreciable risk to human health. However, levels of PAHs in traditionally smoked fish may pose and elevated of risk of cancer if consumed at high rates over a life time. Accurately estimating PAH exposure in cases where aquatic foods become contaminated is often hindered by sample availability. To overcome this challenge, we developed a novel analytical approach to predict PAH loads in resident crustacean tissues based on passive sampling device (PSD) PAH measurements and partial least squares regression. PSDs and crayfish collected from 9 sites within, and outside of, the Portland Harbor Superfund site captured a wide range of PAH concentrations in a matrix specific manner. Partial least squares regression of crayfish PAH concentrations on freely dissolved PAH concentrations measured by PSDs lead to predictions that generally differed by less than 12 parts per billion from measured values. Additionally, most predictions (> 90%) were within 3-fold of measured values, while state of the art bioaccumulation factor approaches typically differ by 5 to 15-fold compared to measured values. In order to accurately characterize chemical exposure, new analytical approaches are needed that can simulate chemical changes in bioavailable PAH mixtures resulting from natural and/or remediation processes. An approach based on environmental passive sampling and in-laboratory UVB irradiation was developed to meet this need. Standard PAH mixtures prepared in-lab and passive sampling device extracts collected from PAH contaminated environments were used as model test solutions. UV irradiation of solutions reduced PAH levels 20 to 100% and lead to the formation of several toxic oxygenated-PAHs that have been previously measured in the environment. Site specific differences in oxygenated-PAH formation were also observed. The research presented in this dissertation can be used to advance chemical exposure estimation techniques, rapidly and cost-effectively quantify a suite of PAHs in biotic tissues, and simulate the effect of abiotic transformation processes on the bioavailable fraction of environmental contaminants. / Graduation date: 2013 / Access restricted to the OSU Community at author's request from April 3, 2013 - April 3, 2014

Les rejets d’argent (Ag) dans l’environnement liés à l’exploitation minière aux diverses applications industrielles (e.g. bijouterie, médecine, photographie, électronique et plus récemment les nanotechnologies) font de Ag un polluant historique et émergent, dont les transferts et les effets dans les milieux aquatiques sont largement sous-documentés. Ce travail présente un premier bilan des sources, du transfert et de la bioaccumulation de Ag dans le système fluvio-estuarien de la Gironde. Le continuum Lot-Garonne-Gironde, connu pour une pollution polymétallique (e.g. Cd, Zn) provenant du bassin de Decazeville, est un système modèle pour l’étude des transferts métalliques du continent à l’océan. Les enregistrements des signaux historiques (~50 ans) de Ag dans les sédiments du Lot en amont (Ag : 0,3 mg/kg) et en aval (Ag : jusqu’à 7 mg/kg) du bassin de Decazeville sont similaires à ceux de Cd, indiquant des sources et des processus de transport/dépôt communs liés à l’histoire minière et industrielle jusqu’en 1986. Le lessivage et l’érosion actuels des terrils provoquent localement des concentrations en Ag particulaire (AgP : 260 mg/kg) et dissous (AgD : 1260 ng/l) dans la rivière Riou-Mort qui sont 2 à 3 ordres de grandeur supérieures aux valeurs typiques. Malgré ces fortes concentrations, la contribution du Riou-Mort aux flux de Ag de la Garonne (AgD : 0,008 à 0,041 t/an ; AgP : 0,306 à 2,44 t/an ; 1999-2009) reste faible (AgP : <11% ; AgD : <6%). La Garonne transporte l’essentiel (63-83%) des apports en Ag à l’estuaire principalement sous forme particulaire (96±2%). La détermination du bruit de fond géochimique régional (AgP/ThP=0,026) a permis d’évaluer (i) la contribution naturelle (20% à 65%) aux flux totaux en AgP et (ii) les flux anthropiques spécifiques de AgP (15±10 g/km²/an et 0,24±0,16 g/hab/an) à l’échelle du bassin versant de la Garonne (La Réole). Dans l’estuaire salin, la désorption par les ions chlorures libère ~60% de AgP vers la colonne d’eau (addition), provoquant des concentrations maximales en AgD (6-8 ng/l) à salinité 15-25. La fraction en Ag désorbé correspond à la fraction potentiellement biodisponible ou réactive (i.e. extractible par HCl 1 M). Ainsi, les premières estimations des flux nets indiquent que l’export annuel de Ag vers le domaine côtier est à 50-80% lié à la phase dissoute (0,64 à 0,89 t/an en 2008 et 0,56 à 0,77 t/an en 2009). Bien que plus biodisponible sous forme ionique Ag+ (dominante en eau douce), l’accumulation de Ag dans les organismes estuariens (huîtres, crevettes et anguilles) reflète la pression d’exposition supérieure en eau saumâtre. L’exposition in situ d’anguilles européennes, espèce recommandée pour la biosurveillance du milieu dans le cadre de la Directive Cadre sur l’Eau, dans des cages à différents sites clé de l’estuaire pendant 3 mois, a mis en évidence les voies directes et trophiques de la contamination en Ag à des niveaux de contamination environnementaux. L’enregistrement historique de la contamination en Ag des huîtres de la Gironde (1979-2007, RNO, Ifremer) indique que le bassin de Decazeville a été la source majoritaire en Ag jusqu’en ~1988. Cependant, l’accumulation maximale de Ag dans ces bivalves après 1993 (de ~40 à plus de 100 mg/kg, poids sec) révèle une contribution croissante de sources additionnelles et contemporaines en Ag comme la photographie, l’ensemencement des nuages (30 à 63 kg/an) ou encore les rejets des eaux usées urbaines de Toulouse et de Bordeaux (42 et 57 kg/an). Ce travail constitue une base nécessaire à l’étude des rejets du cycle de Ag (y compris les nanoparticules) dans le milieu aquatique (quantification, transfert et toxicité) et des risques associés. / Silver (Ag) emissions into the environment from former mining activities and various industrial applications (e.g. jewellery, medicine, photography, electronic products and more recently nanotechnology) make Ag both a historic and an emergent pollutant for which information on its transfer and toxicity in aquatic system are scarce. This work provides a first assessment of Ag sources, transfer and bioaccumulation in the Gironde fluvial-estuarine system. The Lot-Garonne-Gironde River continuum, known for its polymetallic pollution (e.g. Cd, Zn) derived from the Decazeville basin, is a model system for studies on metal transfer from watersheds to the ocean. The relationship between historical records (~50 years) of Ag concentrations in sediment cores from the Lot River, upstream (Ag: 0.3 mg/kg) and downstream (Ag: up to 7 mg/kg) of the Decazeville basin and those of Cd constitutes evidence of a common source and transport/settlement processes due to industrial activities until 1986. High particulate Ag (AgP: 260 mg/kg) and dissolved Ag (AgD: 1,260 ng/l) concentrations in the Riou-Mort River were attributed to current leaching and erosion of slag heaps by rainwater. Those concentrations were 2 to 3 orders of magnitude greater than typical values in the Gironde watershed. However, the Riou-Mort River contribution to the Garonne River Ag fluxes (AgD: 0.008-0.041 t/a; AgP: 0.306-2.44 t/an; 1999-2009) remained low (AgP: <11%; AgD: <6%). The Garonne River provided the quasi totality (63-83%) of Ag inputs to the estuary, mainly in its particulate form (96±2%). The regional geochemical background (AgP/ThP=0.026) was useful to estimate (i) the natural contribution (20-65%) to total AgP fluxes and (ii) the anthropogenic specific fluxes of AgP (15±10 g/km²/a and 0.24±0.16 g/hab/a) in the Garonne watershed (La Réole). In the estuarine salinity, chloro-complexation desorbed ~60% of AgP, causing maximalum AgD concentrations (6-8 ng/l) at salinity 15-25 (addition to the dissolved phase). This quantity was similar to the potentially bioavailable or reactive fraction (i.e. extracted by HCl 1 M). The first estimations of net fluxes suggested that 50-80% of the Ag annual export to the coast occurred in the dissolved phase (0.64-0.89 t/a in 2008 and 0.56-0.77 t/a in 2009). Even if the ionic form Ag+ (the main form in freshwater) is considered as the most bioavailable form, Ag accumulation in estuarine organisms (oysters, shrimps and eels) reflected the higher exposition pressure in brackish water. In-situ caging of European Eels (recommended species for the biosurvey of aquatic systems; European Water Framework Directive) in key sites of the Gironde Estuary during 3 months, highlighted the direct and trophic pathways of Ag contamination at the environmental level. The historical record of Ag contamination of the Gironde Estuary oysters (1979-2007, French Mussel Watch, RNO) indicated that the Decazeville basin was a major Ag source until ~1988. However, the maximum Ag accumulation in oysters after 1993 (from ~40 to more than 100 mg/kg, dry weight) suggested an increasing contribution of additional and contemporary Ag sources like photography, cloud seeding (30-63 kg/a) or Toulouse and Bordeaux wastewater effluents (42-57 kg/a). This work is a basis for future work on Ag (including nanoparticles) cycles and related risks in aquatic systems (quantification, transfer and toxicity).

L'étude sur le potentiel de bioaccumulation des mollusques comme bioindicateur est un effort important à appliquer rigoureusement dans les régions tropicales. Cette thèse présente les résultats de notre enquête pendant deux ans (2012-2013) dans 4 sites côtiers de la baie de Nha Trang de la province de Khanh Hoa (Viet Nam). L'étude a utilise des méthodes d'analyse appropriées pour déterminer la pollution en métaux lourds des sédiments et interpréter la capacité de bioaccumulation de ces métaux lourds dans plusieurs types de mollusques pour la proposer des bioindicateur et évaluer les risques lies a la consommation de ces mollusques provient des substances toxiques. Les résultats de cette étude ont démontré que la concentration de métaux lourds comme Cr, Cd, Cu et Zn ne présent pas les effets biologiques. Un traitement des résultats sur le choix d'une espece comme bioindicateurs, y compris Laternula anatine, Glauconome virens, Katelysia hiantina et Geloina coaxans en terme de bioaccumulation BSAF de métal dans leurs tissus. Les facteurs de bioaccumulation conduisant au choix d'un espèce particulière, la quelle K.hiantina pourrait être le meilleur indicateur de la pollution par les métaux. / The study on the potential bioaccumulation of mollusks as bioindicator is an important effort that contributes to the findings of method in monitoring pollution in an environment of tropical regions. This thesis reports the results of our investigation of heavy metals in mollusks and sediment samples collected from four coastal sites of different environmentally background in Nha Trang bay and adjacent areas, Khanh Hoa province, Viet Nam during 2 years from 2012 to 2013. The study used suitable analyzing methods update to find the bioaccumulation capacity of trace metals in marine ecosystems, evaluation of the bioavailability of potentially toxic substances on human health risks and available for predicting the environmental fat and effects of pollutions. Results from this study demonstrated that the 5 metals As, Cr, Cd, Cu and Zn concentrations of sediments were acceptable or moderate biological effects. These studied mollusk species including Laternula anatine, Glauconome virens, Katelysia hiantina and Geloina coaxans have high potential factors in term of metal BSAF in their tissues. They have served as good bioindicator organisms, in which K.hiantina might be the best indicator of metal pollution as it is high presence, abundance and wide geographical distribution in the study area.