Graduation date: 1974

Graduation date: 1971

Graduation date: 1979

Thesis (MSc)--Macquarie University, Graduate School of the Environment, 1998. / Bibliography: leaves 102-116. / Introduction -- "Being" in environmental and planning theory -- "Knowing" in environmental and planning theory -- "Acting" in planning and environmental theory -- Philosophy in environmental and planning theory -- Conclusion. / This thesis documents and examines seven histories of environmental and planning thought over the last century, drawing on Yiftachel's (1989) classification of planning theories. It provides evidence that environmental and planning theory over time is moving: away from the understanding of nature as an object; away from the notion of a unitary public interest in planning theory; toward an increasing recognition of uncertainty in environmental decisionmaking; away from instrumental rationality in planning decisionmaking; away from hard determinism in urban design and planning control theory; away from direct pollution controls in environmental policy theory.-- This thesis argues that these changes can be understood in the context of broader philosophical shifts around the issues of being, knowing and acting, involving a reevaluation of the relationships between: subject and object; value and fact; cause and effect.-- It suggests that the changes indicate a shift away from philosophical rationalism in policy theory over time. The thesis concludes that neither the extremes of rationalism or relativism provide a sound theoretical foundation for environmental planning. It suggests that future theoretical development is likely to come from the interaction of theoretical approaches influenced by non-Western cultures, and innovations produced by local cultures adapting existing theories to meet their specific needs. / Mode of access: World Wide Web. / 116 leaves

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M.Comm. (Industrial Psychology) / Please refer to full text to view abstract

Magister Scientiae - MSc / Radon has been identified as an important factor that could result in a health hazard by studies all around the world. The health risks can be minimised by preventive measures where radon is highly concentrated as in some mines and homes. Measuring and modelling the radon concentrations in the mine dump soil, can help to deduce the radon flux to identify the problem areas for rehabilitation especially in the cases of gold and uranium mine tailings. Rehabilitation in those cases usually consists of a multilayer cover of solids like crushed rock or clay. A passive method incorporating electret technology was used in this study to determine the radon emanation coefficient of the soil. This investigation also describes the modelling of a depth profile with respect to the radon activity concentration to understand from how deep radon might be migrating, as well as the effect of different diffusion lengths. / South Africa

Field studies were conducted at Lincoln University of Missouri (USA) and Hokkaido University (Japan) to: (i) study the relationships between greenhouse gases emissions and soil properties, (ii) assess the influence of agricultural practices on greenhouse gas fluxes and soil properties and (iii) improve the quantification of greenhouse gases from soil in agricultural fields using geospatial technologies. Results showed that besides soil temperature (T), soil thermal properties such as thermal conductivity (K), resistivity (R) and diffusivity (D) and soil pore spaces indices such as the pore tortuosity factor and the relative gas diffusion coefficient (Ds/Do) are controlling factors for greenhouse gases emissions. Soil thermal properties correlated with greenhouse gases emissions when soil temperature could not. The study has found that predicted Ds/Do and correlate with greenhouse gas fluxes even when the air-filled porosity and the total porosity from which they are predicted did not. We have also showed that Ds/Do and can be predicted quickly from routine measurements of soil water and air and existing diffusivity models found in the literature. Agricultural practices do seriously impact greenhouse gases emissions as showed by the effect of mechanized tillage operations on soil physical properties and greenhouse gas fluxes in a corn and soybean fields. In fact, our results showed that tractor compaction increased soil resistance to penetration, water, bulk density and pore tortuosity while reducing air-filled porosity, total pore space and the soil gas diffusion coefficient. Changes in soil properties resulted in increased CO2, NO and N2O emissions. Finally, our results also confirmed that greenhouse gas fluxes vary tremendously in space and time. As estimates of greenhouse gas emissions are influenced by the data processing approach, differences between the different calculation approaches leads to uncertainty. Thus, techniques for developing better estimates are needed. We have showed that Geographic Information Systems (GIS), Global Positioning System (GPS), computer mapping and geo-statistics are technologies that can be used to better understand systems containing large amounts of spatial and temporal variability. Our GIS-based approach for quantifying CO2, CH4 and N2O fluxes from soil in agricultural fields showed that estimating (extrapolating) total greenhouse gas fluxes using the “standard” approach – multiplying the average flux value by the total field area – results in biased predictions of field total greenhouse gases emissions. In contrast, the GIS-based approach we developed produces an interpolated map portraying the spatial distribution of gas fluxes across the field from point measurements and later process the interpolated map produced to determine flux zones. Furthermore, processing, classification and modeling enables the computation of field total fluxes as the sum of fluxes in different zones, therefore taking into account the spatial variability of greenhouse gas fluxes.

Urea finds common use at most airports in Canada where it is used as an anti-icer or de-icer. Urea contains up to 46% nitrogen which finds its way to the environment around the airport. Of the potential environmental problems, eutro-phication of lakes is of the most concern in British Columbia. Several methods for minimizing the impact of urea de-icer were considered. Urea can be hydrolyzed to ammonia by the common soil enzyme urease on an airport runway and this ammonia can volatilize to the atmosphere. The natural enzymatic activity on runway test sections was found to cause less than 0.5% of the applied urea to hydrolyze with no volatilization after 90 minutes, at room temperature. Supplemental urease was added to pyrex models to test the effect of various conditions on hydrolysis and volatilization. Thirty-two tests were performed at various temperatures (-4, 0, 4, 120C), urease additions (100, 200, 500, 750 mg/model), ice thicknesses (3, 5, 8 mm), urea applications (0.45, 0.9, 1.8 kg/70m2), urea types (Cominco Industrial and Forestry Grade, Sherritt Gordon Mines Industrial Grade) and solar radiations (50 and 100 BTU/h-ft2). An addition of 500 mg urease to the model cuased hydrolysis of 65% of the applied urea and volatilization of 1% at 12°C. Lower temperatures produced poorer results. Relative to the high costs and low efficiency, control of urea through hydrolysis and volatilization on an airport runway is impractical. Biological nitrification-dentrification, breakpoint chiorination, selective ion exchange, and air stripping have high nitrogen removal efficiencies under normal conditions, but are not suitable for winter airport operation. Passage of urea through soil can be an effective method for removal of this de-icing agent if the quantity of nitrate and urea leached to surface waters is low. Published data indicates that soil could be 75-90% efficient in controlling nitrogen loss to surface and ground waters. A reduction in the quantity of urea used on a runway would decrease the environmental impact. The yellow aura produced by the urea-Ehrlich reagent reaction, was used to monitor the movement of urea in 5 mm thick ice at -4°C. After 90 minutes from placement on the ice, the Cominco Forestry Grade aura covered the largest area. On a weight basis, however, the Sherritt Gordon Mines covered the largest area. This greater aura coverage is due to the smaller particle size of the Sherritt Gordon Mines pellets. If the size of the aura can be correlated with the ease of removal of ice from an airport runway, then the Sherritt Gordon Mines-Industrial Grade urea is more effective as a de-icer than either of the two Cominco grades under the conditions tested. Further research is recommended in optimizing the use of urea and soil treatment. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

This study evaluates the toxicity, accumulation, chronic effects and mode of action of methylmercury on the reproduction of the teleost fish, Oryzias latipes. The median lethal concentration, 96h-LC50, for adult Oryzias was + 88+9.8 μg CH₃Hg⁺/1 as determined in a static system. Residue analysis by gas chromatography showed that fish exposed to 43 to 1000 μg CH₃Hg⁺/1 had tissue levels below 40 μg CH₃Hg⁺/g while fish exposed to more than 1000 μg CH₃Hg⁺/1 accumulated methylmercury steadily and reached levels as high as 408.1 μg CH₃Hg⁺/g. Death seems to occur when tissue level reaches 25 μg CH₃Hg⁺/g. Studies on long-term exposure to 0.0, 4,3, 10.7 and 21.5 μg of methylmercury in a flow-through system confirmed this observation. Four-hour exposure of 8.5 and 42.9 μg/1 of methylmercury on alternate days during the fish's normal oviposition period resulted in inhibition of oviposition. This observation occurred only oh days when fish were exposed to methylmercury but not on days when fish were returned to clean water. However, at a concentration of 85 μg CH₃Hg⁺/1, complete inhibition was observed even on days when fish were returned to clean water. High rates of accumulation with low rates of excretion of methylmercury were suggested explanations for these observations. Six-week exposure to 4.3, 10.7 and 21.5 μg/1 of methylmercury resulted in inhibition of spawning. This inhibition was directly related to the log of exposure concentrations. At the end of six weeks, both male and female gonads showed reduction in size; the females were more sensitive. However, hatchability of the spawned eggs was not affected by the exposure. Juvenile fish were very sensitive to methylmercury. After two weeks of exposure, one-week old juvenile exposed to 0.0, 4.3, 10.7 and 21.5 μg CH₃Hg⁺/1 had mortality rate of 2.2%, 54.3%, 64.9% and 99.4% respectively. Synthetic LH-RH, at concentrations of 100 and 1000 ng/g body weight, was effective in stimulating ovarian development in Oryzias. This shows that the LH-RH (synthesis based on structure of porcine LH-RH) has biological activity in Oryzias. When exposed to methylmercury, spawning activities were inhibited. LH injections were able to restore the spawning activities inhibited by the methylmercury treatment, but not LH-RH. However, histology of the pituitary gland showed stimulation of gonadotropic cells by LH-RH injection with no restoration of spawning activities. This suggests that methylmercury- may be blocking the release of gonadotropin. In vitro ovulation was affected by previous exposure to methylmercury. Addition of methylmercury directly to the incubation medium further reduced the percentage of in vitro ovulation in the previously treated fish. Using oocytes from untreated donor fish, the percent inhibition of in vitro ovulation by methylmercury was directly related to the log of doses used. A possible bioassay with in vitro ovulation was suggested. Among the various steroids used (progesterone, cortisone, estradiol and testosterone), cortisone was the only steroid effective in restoring in vitro ovulation blocked by the presence of methylmercury in the incubation medium. Ecological implications of these findings are discussed. / Science, Faculty of / Zoology, Department of / Graduate