<p>Measurements of radon (&sup2 / &sup2 / &sup2 / Rn) concentration in soil gas are routinely used to locate geological fault zones. This study was undertaken to investigate the systematic effects that influence radon soil-gas measurements, in preparation for the first such fault zone measurements in South Africa.</p>

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This study investigates key decision-makers' perceptions of sustainable sea fisheries in Namibia, and explores the possibilities for the future development of education programmes that focus on "sustainability" in the fisheries sector. The concept of "sustainability" and its application in the context of a biological resource, namely sea fisheries, was examined. A series of questions were raised concerning sustainable fisheries: intergenerational implications of patterns of resource use, equity concerns, time horizons, and the protection of marine biodiveristy, among others. Examples from the Namibian and the European Community Sea Fisheries Industries are used to illustrate these issues. In spite of divergent views on what "sustainability" means, the study leads to certain findings that have broader policy implications. Data was collected from semi-structured interviews undertaken with six (6) key decision-makers in the Sea Fisheries Industry of Namibia, then analysed and assessed. The perceptions of key decisionmakers were determined by qualitative analysis in the interpretive paradigm. The data indicated some agreement in terms of what the key decision-makers think about the sustainable utilisation of the fisherjes resources. It is almost impossible to have complete agreement, because the decision-makers are from different contextual backgrounds. Those who make the decisions are more concerned about "how to manage" and those who act on the decisions put more emphasis on economic self-interest. Although the interviewees' perceptions of sustainable fisheries was imperfect, there was broad support for its aims and principles. The study also revealed that the achievement of sustainable sea fisheries development in Wamibia will require broader educational and public awareness programmes to enhance participation in decision-making debates. Formal and informal marine environmental education, from the perspective of "Responsible Fishing" has been emphasised.

Thesis (MTech (Civil Engineering))--Cape Technikon, Cape Town, 2003 / South Africa is experiencing great movements of people from rural areas to towns mainly because of the need to find work. Accommodation is limited and expensive, forcing many to live in informal homes. The municipalities, in an attempt to accommodate as much as they can, provide small plots, which basically can only accommodate a house and a very small garden. This country like other countries of the world has also embarked on numerous low-cost housing schemes to accommodate the homeless. Because of economic realities and because high-rise options are not considered acceptable, the most practical solution has resulted in large-scale low-density urban and suburban housing developments. Low-pitched metal-sheet roofs are provided because they are the most cost-effective. Lack of space within the homes and tiny surround-gardens are major problems to residents seriously limiting lifestyle. Other problems associated with these developments concern environmentally intrusive effects, the need for better security and other social concerns, and storm water runoff. This thesis discusses a usable flat urban and suburban roofing for existing and new houses by means of a system known as 'C-beam'. A usable greened concrete flat roof replaces the traditional pitched metal-sheet. The new roof provides sitting space for family members and is used to grow plants in pots. A construction manual is to be developed by which the constructors will build the roofing without the use of cranes and other expensive sophisticated construction machinery. The house owner can construct their own flooring/roofing; that is, the process will provide additional jobs, and hence positively affect economy. The manual includes the means of effective control by municipal authorities to ensure adequate and safe standards. Greening of the roofs will not only provide the potential for growing food from the plants, but it will also improve the environment of the area, including the reduction of storm water run-off, by retaining some water in the soil on rooftops.

Thesis (MTech (Environmental Health))--Cape Peninsula University of Technology, 2011. / World wide urban rivers are the most utilised and degraded. A variety of everyday sources of metal pollution exist that is entrenched in the modern way of life. Lately there has been a tremendous growth in the establishment and development of human settlements, both formal and informal in the Cape Town area. The surroundings of the Kuils River are not excluded from this. There are various communities in close proximity to the Kuils River. Due to this, more industries are also being established. This has caused an increased production of potential environmental pollutants, including metals. The aim of the study was firstly, to identify potential sources of metal pollution along the entire length of the Kuils River, in order to identify sampling sites. Secondly, to identify the metals contaminating the water and sediment of the Kuils River. Thirdly, to determine the bioaccumulation of metals in freshwater snails (Physa ecuta). Four sampling sites were identified along the Kuils River. Freshwater snails (P. acuta), sediment and water were collected every 2 months for a period of one year. The following metals were investigated: Aluminium (AI), Cadmium (Cd) Cobalt (Co), Chromium (Cr), Copper (Cu), Iron (Fe), Lead (Pb), Manganese (Mn), Nickel (Ni.) and Zinc (Zn). Samples were digested with 55% nitric acid. The Inductively Coupled Plasma - Atomic Emission Spectrometer (ICP-AES) were used for metal analyses. The results were statistically analysed by means of ANOVA on ranks using the Sigmastat statistical package. Results revealed that most metals found in water, sediment and snails had significantly higher concentrations at site 1. This is possibly due to input from the surrounding urban area and nearly agricultural activities. Water concentrations of AI, Cu, Mn and Zn were higher than the DWAF (1996) guidelines. Sediment was mostly contaminated with AI, Fe, Pb and Zn, while the snails contained significant levels of Cu, Fe, Mn and Zn. Further investigations involving toxicity testing should be conducted to determine the toxicity of these metals to (Physa acuta).

Chemical synthesis is not complete without waste treatment. There is no chemical process that does not produce waste. The untreated effluent discharged by chemical industries poses a major environmental concern. This dissertation describes the results of an investigation carried out on the formation of by-products (impurities) during the synthesis of atrazine by neutralization of the reaction mixture during the actual synthesis procedure, and prior to disposal using carbon dioxide or hydrochloric acid. The main objectives for the said investigation were: {u100083} To optimise the reaction parameters to obtain a higher yield and purity of atrazine. {u100083} To evaluate the use of carbon dioxide and hydrochloric acid to neutralise the reaction mixture. {u100083} To study the solids present in the effluent. Synthetic reactions were carried out in the presence of an organic solvent, methyl isobutyl ketone (MIBK). The synthesis of atrazine was optimised in terms of addition sequence and rates of amine reagents and base (proton acceptor) additions by means of bench scale reactions. It was found that addition of a neutralising step (hydrochloric acid or carbon dioxide) to neutralise the basic reaction mixture prior to and after addition of the secondary amine and the base minimizes the formation of by-products. Of particular importance in ensuring high yields and selectivity to the atrazine product was temperature control, pH control, reagent ratios, addition rates and mixing. The latter was important in view of the rapid reaction of amine/NaOH with cyanuric chloride, as well as the possible reaction of mono-i, the reaction intermediate, with IPA in cases of excesses of reagent. Under optimum conditions, an atrazine composition of >97% was achieved where the resultant product was well within stipulated product specifications.

M.Sc. / The Johannesburg Metropolitan area drains sewage from approximately 1,3 million people which is treated at five different works. The Northern Works discharges approximately 50 Mt of effluent per day, which, together with 27 MX from Alexandria Works flows into the Jukskei River and hence to Hartebeespoort Dam ...

Magister Scientiae - MSc / Measurements of radon (222Rn) concentration in soil gas are routinely used to locate geological fault zones. This study was undertaken to investigate the systematic effects that influence radon soil-gas measurements, in preparation for the first such fault zone measurements in South Africa. The measurements were made at two zones (called A and B for ease of reference) on the iThemba LABS site, which is located in Faure, on the Cape Flats, Western Cape (South Africa). There are no known faults located in the vicinity (~ 10 km) of the site. The radon measurements were made using a RAD7 (Durridge) radon monitor, which makes use of alpha spectrometry. A steel soil probe, which is inserted into the soil, was used to transfer radon from a certain depth in the soil to the RAD7 monitor via a flexible tube. Measurements were made at five sampling areas (three in zone A (A1, A2 and A3) and two in zone B (B1 and B2)), on the site during the months of May, August and October 2006. The variation of soilgas radon concentration as a function of depth, time of day and meteorological data were studied. The depths at which measurements were made were generally 25, 50, 75 and 100 cm. (In August and October, some of the depths were not considered due to a high water table.) Atmospheric temperature, air humidity, wind speed and atmospheric pressure were measured using a portable weather tracker (Kestrel 4000). The highest radon concentrations recorded were 11000 ± 776 Bq.m-3 and 26900 ±1370 Bq.m-3 at a depth of 100 cm in zone A and B, respectively (May). Generally, the radon concentrations were significantly quenched during the August and October measurements relative to the May values. The May soil-gas radon concentration profiles as a function of depth were fitted using a chi-square minimization procedure in order to extract diffusion lengths. A functional form derived from a onedimensional diffusion model was used for the fitting. One the parameter of the fit function is the 226Ra activity concentration. This was determined by means of gammaray spectrometry (in-situ and laboratory-based). A MEDUSA-type detector system comprising a CsI(Na) scintillator crystal and a GPS signal receiver were used for the in-situ measurements. A high-purity germanium detector (2.6 keV FWHM resolution at 1.33 MeV, 45 % relative efficiency) was used for the laboratory measurements. Significant seasonal variations in soil-gas radon concentration were observed (concentrations were generally much lower during or after the rainy season due to the presence of a high water table, and possibly the presence of more lush vegetation causing more radon to escape to the atmosphere). Significant (up to a factor of 2) local variation in radon concentration was observed at a particular depth, in a particular zone during autumn (just after the dry season). The soil-gas radon concentrations (for depth > 25 cm) in zone B were ~ factor of 2 higher than in zone A. The difference is largely due to the fact that the 226Ra soil activity concentrations in zone B were higher than in zone A (by a factor of ~ 1.6). Significant correlations (with coefficients > 0.6) were found between soil-gas radon concentrations and soil 226Ra activity concentrations (using a combination of zone A and B data). No significant, robust correlations (with correlation coefficients > 0.6) were found between soil-gas radon concentrations and meteorological parameters. Often contradictory results (in terms of the sign of the coefficient) were found. From measurements made at two depths (25 and 50 cm) in zone A, over a 24 hour period, there is evidence of a statistically significant variation between night and day radon concentrations, with the former being higher. The one-dimensional diffusion model used to fit the measured radon concentration depth profiles failed to fit the data when the results for a depth of 25 cm were included. When the 25 cm data were excluded the fits yielded diffusion lengths that are more realistic, although significant variations in diffusion length were found in a particular zone. / South Africa

Please read the abstract in the section 00front of this document / Dissertation (MSc)--University of Pretoria, 2005. / Geography, Geoinformatics and Meteorology / Unrestricted