Increased releases of cadmium to the aquatic environment have raised concern over the potential for adverse impacts on freshwater organisms in affected aquatic bodies. This thesis explored the responses of a common freshwater amphipod, Gammarus pulex (G. pulex) to sublethal concentrations of cadmium under different environmental conditions and at various stages of the lifestyle. Endpoints studied encompassed molecular, cellular, physiological and behavioural changes, to enable a comprehensive analysis of the effects of the organism. Exposure to sublethal concentrations of cadmium (Cd) (0.001, 0.005 and 0.01 mg Cd L–1) for 7 and 14 days, influenced the percent survival, induced lipid peroxidation and damaged DNA in haemolymph cells of G. pulex. These concentrations also reduced feeding and ventilation rates as well as the motility, in particular of the females, with increasing Cd concentration and time of exposure. Furthermore, Cd accumulation from water in the body tissues of the amphipods was lower than in their food, with increasing Cd concentrations. These results illustrate how concentrations of Cd below the Environmental Quality Standard for European waters can cause sublethal molecular and cellular damage after relatively short periods of exposure. Histopathological effects of Cd on the gills and hepatopancreas (mid-gut gland) were examined using light, scanning and transmission electron microscopy. Multiple effects were observed on the tissues and cell organelles including external alternations in the muscular fibres of the hepatopancreas, lysis of microvilli and morphological changes in mitochondria. Exposure to 0.01 mg Cd L–1 altered the epithelial layer of the gill, causing vacuolation and lysis across the whole gill structure. Mitochondria showed damage to the inner membrane, shortened cristae and swelling, with an increase in apoptosis at concentrations of 0.005 and 0.01 mg Cd L–1. Collectively, these results document the adverse effects of Cd on target organs at concentrations within the range found in freshwater bodies. An investigation of the effects of water hardness on bioaccumulation and toxicity showed that hardness of water inhibited Cd toxicity and protected the juveniles during long term exposures, without affecting growth rate and food consumption. Soft water reduced the rate of survival, growth rate and food consumption during chronic exposure to low Cd concentrations, and facilitated Cd accumulation in the body parts compared with juveniles exposed in hard water. The results show that water quality plays a vital role in reducing or increasing detrimental effects of low Cd concentrations on the early life stage of amphipods which are a source of food for many species in aquatic environments. Exposure to Cd led to an increase in metallothionein concentrations in the amphipods in both hard and soft water. It also caused disruption to ion/osmoregulation, which may represent one mechanism of compensation for the ions lost in the amphipods exposed to Cd in soft water. In conclusion, these results add to the body of evidence describing the sublethal toxicity of Cd, a priority pollutant, to a common freshwater sentinel species. These results are of relevance for future environmental management and remediation approaches, because they provide scientific data to help in assessing, interpreting and understanding the effects of the heavy metal Cd in freshwater environments.

The work presented here is an experimental investigation of the effect of cylindrical geometry on electrical conductivity, in which single-crystal samples of cadmium at the temperature of liquid helium are used, with the diameter on the order of the electron mean free path.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

In this project the link between species in solution and the solid state was considered. This is relevant due to the many applications in life where there is this interchange between solid and solution state, for example drug design, environmental metal speciation and the manufacture of materials that are in contact with solution (such as outdoor surface coatings, containers and so on). Complexation of two metal ions, namely cadmium(II) and bismuth(III), was studied. With bismuth showing so much promise in medicinal applications it was pertinent to investigate this interchange since the intake of medication is generally in the solid form which then converts to solution species as it dissolves in the body where it becomes active. For cadmium it is mainly the environmental concerns which we are faced with that call for the examination of speciation of complexes in solution, as well as their disposition upon precipitation or crystallization. A correlation was found between solution species and the complex that was isolated in the crystalline form with regards to pH for a number of metal-ligand species. We show how the results from solution experiments (achieved using direct current polarography) and those of crystalline complexes can complement each other when using species distribution diagrams as the intermediary. The distribution of species can be varied by changing the concentration and ligand-to-metal ratio at which the species distribution diagram is plotted. It is this characteristic which allows the solution and crystalline complexes – which are achieved using differing experimental conditions – to be correlated. The speciation diagram for a metal-ligand system, calculated using formation constants derived from solutions studies, was used in most instances to target specific species for their growth in the solid state. In some cases the solid state structure was used to confirm a suspected solution species, and in others the result was used to identify minor solution species which cannot be detected by the techniques used in determining formation constants. Further, we show that doing solution experiments at a range of temperatures can also aid in elucidating these minor species. The growth of crystalline species at low pH was important for this work because the pH titrations used for solution experiments were conducted from below pH 2 where the diffusion junction potential is large and changing. An in-situ witness ion was incorporated into the experiment to monitor the shifts due to the diffusion junction potential so that they could be compensated for. Additionally, for bismuth-ligand systems, hydrolysis and complexation with nitrates occurs in this same pH region. The formation constants and the species identified below pH 2 therefore do carry some uncertainty, so obtaining crystalline complexes of these species provides further confidence in their prediction in solution.

by Hon-ming Lam. / Thesis (M.Ph.)--Chinese University of Hong Kong, 1987. / Bibliography: leaves 193-217.

Philosophiae Doctor - PhD / The cadmium nuclei have traditionally been regarded as among the best examples of spherical vibrational nuclei. However, advances in nuclear spectroscopy have begun to detail the properties of these nuclei at the two and three vibrational phonon levels, casting doubts on the vibrational assumptions. In particular, the properties of the excited 0+n (for n 2) levels are key to any vibrational model. Excited 0+ states can arise in nuclei in association with the nucleon pairing degrees of freedom, and in model spaces with collective shape degrees of freedom. This thesis reports details of the excited 0+n levels in the even-even nuclei 110;112Cd and 116Sn, and the excited 9 2 + states in 117Sb, investigated using two-proton stripping reactions. The 108;110Pd(3He, n )110;112Cd, 114Cd(3He, n )116Sn and 115In(3He, n )117Sb reactions were investigated using AFRODITE spectrometer in conjunction with a wall of 12 plastic scintillator detectors placed 2 m away from the target chamber.

Extraction, production, utilization and disposal of material resources have been undertaken continuously for much of human histories. Unavoidably, all of these activities have disturbed our environment, and subsequently have been harmful to humans and ecosystems in this and future generations. Due to time lag associated with both environment impact and the effects of measures taken to reduce this impact, existing approaches (i.e. monitoring and reacting) do not give sufficiently rapid feedback for effective environmental management. With regard to the complexity and concern related to environment-health chain effects, there is currently no environmental tool or approach that can provide comprehensive information and indicators covering all major environment and health themes, to enable decision makers to make informed judgements about regional policies and plans, relating to the sustainable use and disposal of material resources. Consequently, there is a need for developing a new approach by taking account of a multidisciplinary concept used in this thesis. Substance Flow Analysis (SFA) has been mainly applied in order to provide input information for Health Risk Assessment (HRA). The SFA approach provides the quantity of the substance that is transported (flows) and stored in the system (stock), and of which sub-system, flow, and process is the greatest concern. The HRA approach provides estimates of human health risk associated with site, activity and facility. An environmental fate and transport model is another key knowledge area incorporated into the HRA process. An integrating method of SFA, environmental fate and transport, and HRA is developed and illustrated by a case study of cadmium in Australia. This thesis shows that this new integration of existing stand-alone methods can provide holistic information and useful indicators covering all significant economic activities, environment, flows, and health risk assessment for selected substances. This enables better decision making on the use and disposal of substances at a range of levels in the economy, from corporations to regions and nations.

Graduation date: 1996

Thesis (Ph. D.)--West Virginia University, 2007. / Title from document title page. Document formatted into pages; contains xi, 120 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 117-120).

Thesis (Ph.D.)--University of Delaware, 2006. / Principal faculty advisor: Robert G. Hunsperger, Dept. of Electrical and Computer Engineering. Includes bibliographical references.