School of Earth Sciences - Theses
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ItemLeachate chemistry of two modern municipal waste landfills in Melbourne, VictoriaStrudwick, Darryl Grant ( 1999-11)This study investigates the occurrence and chemical composition of leachate at Clayton South and Brooklyn Municipal waste landfills in Melbourne, Victoria. Both are ‘modern’ municipal waste landfills, being engineered and managed consistent with current regulatory requirements. These landfills accept only putrescible and solid inert waste, but not soluble chemical, hazardous, liquid or prescribed industrial waste. (For complete abstract open document) Analyses of an extensive range of chemical parameters reveals a complex mixture of inorganic and organic compounds, similar to those of international authors researching leachate chemistry. Dominant ions in these leachates are NH4+, Na+, HC03- and Cl-. Except for Fe, heavy metals are not present in significant concentrations (mostly
ItemDetection of uranium(VI) in groundwater using a field electroanalytical techniqueDwyer, Athene Tracy ( 1999)In this thesis electroanalytical methods are investigated and a new method developed to determine uranium(VI) in groundwater samples. Differential pulse polarography, differential pulse voltammetry and adsorptive stripping voltammetry methods, with appropriate mercury drop electrodes, were optimised using the adsorptive chelate 2,5-dichloro-3,6-dihydroxy-l,4-benzoquinone (chloranilic acid). An alternative adsorptive stripping voltammetry method, with a hanging mercury drop electrode, was optimised using the chelate 8-hydroxyquinoline (oxine). The liquid mercury requirements of these techniques limit their use in the field. Therefore, mercury film electrode methods that are potentially better suited to field conditions are investigated. Chloranilic acid was found to be a suitable chelating agent for uranium determination in combination with a hanging mercury drop electrode, but the reduction of chloranilic acid was a concern. A new mercury film electrode determination method using chloranilic acid was developed but was found to result in the deterioration of the MFE to the extent of rendering the method unsuitable for uranium determination. An adsorptive stripping voltammetry, MFE method with oxine was investigated. The inability to remove the uranyl-oxine reaction products from the MFE created a memory effect that contributed to a lack of accuracy and precision when performing standard addition determinations. This interference was a significant factor in the inability to reliably measure a uranium response using an adsorptive stripping potentiometry method with oxine. The technique of square wave adsorptive stripping voltammetry with oxine in combination with a hanging mercury drop electrode was found to be the most appropriate method for uranium determination. The method was fast, sensitive, precise and accurate when analysing standard solutions. A low detection limit of 2.7 µg/L was achieved. Groundwater and surface water samples were analysed by the AdSV, HMDE method with oxine. The mineral spring water samples from Daylesford, Victoria, were high in ionic content and contained interfering ions. The unacidified samples contained high concentrations of dissolved C02 that needed to be removed prior to sample analysis to prevent pH changes during analysis. Of six unacidified samples uranium was found in only one sample, the Tipperary Spring sample at 4.9 µg/L U(VI). Interference prevented confirmation of this concentration in the acidified Tipperary Spring sample. The construction of a linear standard addition plot with a positive x-intercept was a common outcome for both the unacidified and the acidified spring samples. The uranium concentration was determined in three surface water samples collected from the Ranger Uranium Mine in the Northern Territory. Matrix interference in these surface water samples resulted in non-linearity for two standard addition determinations. A third sample was successfully analysed to give a concentration of 23 µg/L U(VI), which is in good agreement with an independent determination. The unselective nature of oxine was found to result in significant interference when analysing environmental samples by the AdSV, HMDE method with oxine. This method was found to be inappropriate for field analysis of environmental samples. However, in a laboratory environment the AdSV, HMDE method with oxine was the best performing method when determining uranium in standard solutions.
ItemTectonic geomorphology of the Bogong and Dargo High Plains region, east Victorian highlands, AustraliaOrr, Meredith Lee ( 1999)The Australian Alps, a sub-region of the Australian Eastern Highlands, have enigmatically high elevations of relief for a highland belt renowned for its ancient origins and landscapes. In debates over the Eastern Highlands history, the development and significance of the Alps have been under-represented. This study defines the morphological extent of the Australian Alps and investigates their tectonic and erosional development. The focus of investigation is the Bogong and Dargo High Plains area and the broader surrounding highlands region. The Cainozoic history of this area has not been investigated in detail since last century. The geological record of the region has substantial gaps, and the erosional history is the main indicator of tectonic change. A methodological structure different to traditional approaches is devised for this study. Cause and response are compared on a process geomorphology basis. Causes investigated are (1) intra-highland tectonics and (2) basin tectonics and sea level change. Denudational relief change is the main response investigated. Spinal and temporal comparison of quantitative results enables relationships to be determined. Peak height distribution and relief observations are used to define the morphological context of the Australian Alps. Within the Alps, the high plains area is used as a case study. Tectonic constructional morphology is investigated using peak height distributions, lineament analysis, tectonic landforms and lava offsets. A Cainozoic fault block is identified, and reactivated fault displacements are determined for bounding and intra-block faults. The erosional development of the area is determined and compared with the constructional morphology results. The sub-volcanic relief of the Bogong Volcanic Province is mapped and compared with post-volcanic stream incision. Guidelines are established for interpreting strath terraces and strath terrace long profiles are used to reconstruct the post-volcanic stream erosion development. Sources and magnitudes of oversteepened stream reaches in the present rivers are identified. Spatial and temporal relationships between fault reactivation and stream incision are determined, and the relative roles of active and passive tectonics are assessed. The tectonic and erosional development of the fault block is reconstructed in cross-sectional form. Finally, the proportion and nature of highland margin-derived stream incision is identified. This study finds that the Australian Alps were substantially affected by fault block uplift during Oligocene, with more minor phases in the Miocene and Pliocene. Broader highland margin warping accompanied fault block uplift. Uplift amounts varied between 150m and over 1000m according to proximity to major faults. Stream incision was upstream-increasing and periodic, with three incision phases during the Oligocene and Pliocene. The later phases include a possible isostatic rebound component. An additional incision phase unrelated to uplift occurred in the Gippsland Basin catchment during the Quaternary. The Australian Alps is delineated here as a separate entity within the Eastern Highlands, with its own tectonic history. Cainozoic uplift created the higher elevations and greater relief of the Alps. This history is not representative of the Eastern Highlands generally, and it should not be used as a guide to a ‘united’ Eastern Highlands uplift. The highlands consist of a ‘patchwork’ of landscape evolution scenarios, rather than a single tectonic province. More definable tectonic histories can be derived from erosional regions of geologically unrecorded time using a process geomorphology perspective. This study provides a suggested step towards redressing interpretation problems recognised in landscape evolution studies generally.