Thesis (Ph. D.)--University of Chicago, 1936. / Descriptive letterpress on versos facing the plates. Lithoprinted. "Private edition, distributed by the University of Chicago Libraries, Chicago, Illinois." "References cited": p. 50-53.

Published also as author's Habilitationsschrift. / Added t.-p.: Zoologica ... Hrsg. von C. Chun ... hft. 62. "Literatuverzeichnis": p. [129]-132.

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There is an increasing concern over the safety of engineered nanoparticles (ENPs) to humans and the environment. It is important that the environmental risks of these particles to be tested under research and regulatory schemes, e.g. Nano Risks to the environment & Human Health (NanoReTox) under Seventh Framework Programme (FP7) in EU. Due to their unique properties and the fact that their detection and characterization in complex matrices is challenging, classic analytical methods and test approaches for assessing environmental risk may not be appropriate for ENPs. In this paper I present the challenges associated with ENPs exposure to the estuarine environment and the testing of a chosen ENPs to generate data on ecotoxicity in the test estuarine organisms for further consideration of risk assessment of marine environment. Careful consideration was given to the selection of the test materials (benthic organisms Nereis diversicolor and Scrobicularia plana), the test system and the test exposure conditions (CdS ENPs and aqueous CdS added to filtered natural seawater with a concentration of 10 µg L-1). Evaluation of the exposure effects was carried out by behavioral tests (burrowing kinetics and feeding rate) and biochemical responses (quantification of biomarkers). Multispecies Freshwater Biomonitor®  (MFB) tests and GST analysis results show significant differences in between control group and CdS NPs exposure one, indicating that CdS NPs are potential to cause sublethal effects in test organisms. Our knowledge in environmental risk assessment of ENPs is still limited. Coordinated research is required to gain a better understanding of the factors and processes affecting ENP fate and effects in the environment as well as to develop more usable, robust and sensitive methods for characterization and detection of ENPs in environmental systems. / NanoReTox, FP7 NMP Work Programme

L’industrialisation de l’étang de Berre au cours du 20ème siècle s’est accompagnée d’importants rejets en éléments traces métalliques (ETM) qui ont été en partie accumulés dans les sédiments et sont aujourd’hui susceptibles d’être remobilisés vers la colonne d’eau ou d’être intégrés dans le réseau trophique et d’entrainer un risque écotoxicologique.La reconstitution de l’évolution temporelle et spatiale de la contamination des sédiments montre que les niveaux de contaminations actuels des sédiments de surface sont les plus bas depuis plusieurs décennies en lien avec l’efficacité des réglementations sur les rejets industriels mises en place dans les années 1970. Ces niveaux sont faibles à modérés en surface mais de très fortes contaminations existent quelques centimètres sous la surface des sédiments.Le rôle des oxy-hydroxydes de Fe ou de Mn et des sulfures dans le contrôle de la mobilité des ETM dans le sédiment et leurs flux à l’interface eau/sédiment a pu être démontré grâce à la modélisation du transport et des réactions des composés chimiques et des ETM dans les eaux interstitielles, de leurs profils de concentrations dans la fraction réactive de la phase particulaire et d’expérimentations en conditions contrôlées au laboratoire. L’oxygénation de la colonne d’eau constitue le principal paramètre influençant cette mobilité et ces flux, et l’influence d’une réoxygénation des fonds dans le Grand Etang est discutée.Enfin, la biodisponibilité des ETM et le stress (géno)toxicologique qu’ils peuvent constituer pour un organisme benthique cible, le polychète Nereis succinea, ont été évalués par l’estimation des fractions potentiellement biodisponibles dans les sédiments (extractions chimiques et Diffusive Gradient in Thin-films), par la mesure des concentrations bioaccumulées et par l’utilisation de biomarqueurs de défense (métallothionéines) et de dommages (tests de génotoxicité). Certains ETM qui sont fortement bioaccumulés représentent un risque potentiel et pourraient être impliqués dans la dégradation de la macrofaune benthique. / The industrialization of the Berre lagoon in the 20th century was accompanied by large releases trace metals, which were partially accumulated in sediments and are now likely to be remobilized to the water column or be integrated into the food chain and cause an ecotoxicological risk.The reconstruction of the temporal and spatial trends of sediment contamination shows that current levels of contamination of surface sediments have been the lowest for decades in agreement with the effectiveness of regulations on industrial releases set up in the years 1970. These levels are low to moderate in surface but very high contamination exist a few centimeters below the sediment surface.The role of Fe and Mn oxy-hydroxides and sulfides in controlling the mobility of ETM in the sediment and fluxes at the water/sediment interface has been demonstrated through the modeling of transport and reactions of chemical compounds and trace metals in the pore waters, their concentration profiles in the reactive fraction of the particulate phase and experiments under controlled laboratory conditions. The oxygenation of the water column is the main parameter influencing the mobility and fluxes and the influence of reoxygenation of bottom water column in the Grand Etang is discussed.Finally, the bioavailability of trace metals and adverse effects they may constitute for a target benthic organism, the polychaete Nereis succinea, were evaluated by estimating the potentially bioavailable fraction in sediments (chemical extractions and Diffusive Gradient in Thin-films), by measuring bioaccumulated concentrations and by the use of biomarkers (metallothioneins and genotoxicity assays). Some highly bioaccumulated trace metals pose a potential risk and might be involved in the degradation of the benthic macrofauna.