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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

An assessment of selected metal pollutants in Durban Harbour

Paul, Vimla January 2001 (has links)
Submitted in partial fulfillment of the requirements for the Degree of Master of Technology in Chemistry, M.L. Sultan Technikon, 2001. / The purpose of this study was to determine the concentration of selected metals in Durban Harbour water and sediments. Four sites were selected for the investigation. The water and sediment samples were collected from July 1998 to July 1999 to accommodate seasonal changes / M
32

Recommendations on land usage in La Mercy airport's simulated noise pollution zone

Goldschagg, Paul Louis 11 February 2014 (has links)
M.A. (Geography) / The development of a new airport usually brings with it the problem of aircraft noise pollution for land users located within about 15km of the airport boundaries. Excessive aircraft noise levels can cause health problems for residents and workers, and be responsible for a decrease in residential property values in the noise impacted areas. This dissertation reviews the problems associated with aircraft noise, examines the predicted noise impact of aircraft operations at the proposed airport at La Mercy in KwaZulu-Natal in South Africa, and concludes with recommendations for future land use around the airport. A number of relatively small urban settlements (Tongaat, Verulam, Waterloo, La Mercy, Umdloti Beach) are located around the La Mercy airport site. Almost all of the land not used for urban sett~ements is used for cultivation of sugar cane - very little land remains undeveloped. The agricultural land will probably eventually be converted to urban use, given the close proximity to Tongaat, Verulam and Durban. As such, comprehensive land use planning may still be done in order to avoid development of land for uses which will not be compatible with the anticipated aircraft noise levels. The Federal Aviation Administration's (FAA of the United States) computerised Integrated Noise Model (INM), designed to model aircraft noise impact was used to derive contours representing aircraft noise exposure around the airport. Taking factors such as airport elevation, mean temperature, runway usage, aircraft type, and flight routes into account, a set of contours unique to the airport at La Mercy were produced. By overlaying the noise contours on land use maps, land uses which would be incompatible with aircraft noise, should the airport be constructed were identified. Recommendations were then iii made on future developments in those non noise compatible areas. Much of Tongaat would be exposed to a moderate noise impact, whilst small portions receive a substantial impact. The whole settlement of Waterloo, and the southern portion of Verulam would be exposed to a severe noise impact. The central and northern portions of Verulam would receive substantial and moderate impacts respectively. Mount Edgecombe and Duffs Road would be exposed to a substantial impact, whilst the northern suburbs of Durban including Westville would encounter a moderate impact. An examination was then made of the general principles for land development - physical requirements of commercial, industrial and residential land use, and locational requirements of these land users in relation to one another. Thereafter, undeveloped land (undeveloped from an urban point of view ie. land used for sugar cane cultivation) was identified, and broad recommendations made for developing that land for urban use, taking general land use development principles into account
33

Die biologiese groeipotensiaal van die Jukskeirivier

Jansen, Estelle 10 April 2014 (has links)
M.Sc. (Botany) / Eight sampling points were selected on the Jukskei River so that the impact of inflows from various localities on the quality of the river water could be determined. Samples were taken every two weeks from the 4th April 1983 to 19th March 1984. The temperature, conductivity, dissolved oxygen and pH of the water were determined on site. Determinations of total phosphorus (as p-po1-), nitrate (NO), chloride (C11 and chlorophyll a were done. After filtration the water of each sample was inoculated with Euglena gracilis and incubated for four days under controlled conditions after which the Euglena chlorophyll-content, primary productivity and biological growth potential were measured...
34

Development of a sediment quality triad approach to evaluate sediments in marine and freshwater environments of South Africa

Shaddock, Bridget Florence 15 July 2014 (has links)
Ph.D. (Aquatic Health) / Please refer to full text to view abstract
35

Risk assessment of inhaled and ingested airborne particles in the vicinity of gold mine tailings : case study of the Witwatersrand Basin

Maseki, Joel 25 November 2013 (has links)
M.Sc. (Geography) / Severe Aeolian deposition of windblown dust from mine tailings storage facilities (TSFs) is a common phenomenon on the Witwatersrand, especially during the spring windy season. For communities around tailings storage facilities, this poses health and environmental challenges. This dissertation estimates the risk of adverse health effects resulting from human exposure to hazardous elements in particulate matter (sub 20 μm diameter) for selected tailings storage facilities: East Rand Gold and Uranium Company (ERGO); East Rand Proprietary Mine (ERPM); Crown Gold Recoveries (CGR) and Durban Roodepoort Deep (DRD). Samples of surface material from these TSFs were analysed for heavy metal content using the ICP-MS method. Other than the expected gold, five heavy metals (arsenic, cadmium, chromium, lead and uranium) exhibited enrichments in the tailings material significantly above average (greater than a factor of 2) crustal composition. These elements were selected for comprehensive risk assessment through airborne exposure routes. The mean ambient particulate concentration in air of 540 μg m-3 (used in the risk calculations) was based on a conservative worst-case exposure scenario. U.S. Environmental Protection Agency (US EPA) risk assessment methods were used to determine the inhalation and ingestion hazard quotient and hazard indices for adults and children. The sum of the hazard indices was below the non-cancer benchmark (hazard indices 1.0) considered to be acceptable for a lifetime exposure. The risk cancer included the excess life cancer risk for the inhalation and the ingestion risk. The total risk for both exposures was within the range of 1 in 1 000 000 to 100 in 1 000 000 - taken as “acceptable risk” by the U.S. Environmental Protection Agency for adults and children.
36

Pollution control investment decisions and policy preferences of senior managers of the Southern African fish processing industry

Lipschitz, Steven January 1990 (has links)
Bibliography: pages 134-147. / Pollution control regulations directed at the land-based factories of the Southern African fish processing industry do not appear to promote the required level of investment in pollution control systems. Two self-administered mail-questionnaires comprising undisguised fixed-alternative and open-ended questions were constructed to survey the opinions and viewpoints of a census consisting of twenty-seven senior managers responsible for making pollution control investments in the demersal and pelagic sectors of the fish processing industry. The first questionnaire was directed at establishing the relative importance of factors that influence waste and pollution control investment decisions as well as the perceptions and preferences of managers with regard to various pollution control policy options. Descriptive statistics such as the modal class were used to summarize the distribution of opinions and viewpoints within the research population. Rank ordered preference data was analyzed using a multidimensional unfolding computer algorithm. This structural multivariate statistical method is a special case of non-metric multidimensional scaling that generates perceptual maps which can aid in the discovery of the hidden structure underlying multidimensional decisions. Investments in waste and pollution control do not appear to have a high priority when compared to other strategic investments that the fish processing industry managers may make. The relative importance of factors that could influence the managers of the industry to invest in waste control equipment appear to be determined by the perceived financial returns that can be expected from such investments. Findings suggest that pollution control legislation is rendered ineffective due to inadequate enforcement. However, it appears that existing legislation needs to be rationalized in order to facilitate compliance. The most favoured pollution control instruments were those that lowered the cost of legally mandated expenses such as subsidies and income tax allowances. These were followed by permit systems which specified the allowable characteristics of discharges while allowing individual companies freedom of choice as to the method of achieving compliance. The second questionnaire was used to verify the researcher's interpretation of the findings and preliminary conclusions drawn from the replies to the first questionnaire.
37

Ambient air quality impacts of a coal-fired power station in Lephalale area

Muthige, Mavhungu Sydney 04 March 2014 (has links)
Lephalale Municipality is a predominantly rural Municipality with 38 villages, two townships (Marapong and Onverwacht) and one town, Lephalale. Lephalale, formerly known as Ellisras, is a town situated in the “heart of the Bushveld” in Limpopo province. The town is growing rapidly and more industries are becoming concentrated within this small town. The construction of Medupi power station which is underway and other projects such as the expansion of Grootegeluk mine (coal 3 and 4 projects), and road developments in the area; have led to concern about the ambient air quality of the area. Other possible future projects are the Coal to Liquid project by Sasol and the Coal Bed Methane project by Anglo American Thermal Coal. The purpose of this study is to determine the ambient air quality impact of the Matimba power station in the Lephalale area. The AERMOD model and ambient air quality data obtained from Eskom’s Grootstryd and Marapong monitoring stations were used to assess the ambient air quality of Lephalale. Sulphur dioxide and Nitrogen oxides were investigated. Both the model’s results and the ambient air quality monitoring data indicated that the power station contributes to high -ground level concentrations of Sulphur dioxide. AERMOD simulated the nitrogen oxides results as nitrogen dioxide. From the study it is concluded that the power station is not the only source of nitrogen oxides. Nitrogen oxides concentrations were associated with low-level sources. The relationship between the criteria pollutants in this study was assessed. The study found that there is no relationship between sulphur dioxide and nitrogen oxides. This finding was used to support the idea that sulphur dioxide and nitrogen oxides are from different sources. It was also established that seasonality has an influence on the ground level concentrations of pollutants in the area.
38

An assessment of the foliar heavy metal contamination in the Palabora Mining region

Kendall, Louise 07 February 2014 (has links)
This study was conducted in order to ascertain the levels of elemental concentrations in tree leaf and leaf litter samples collected in two areas at the Rio Tinto Palabora Mining Company. The elemental content in leaves from trees growing in the smelter plume deposition area and in the area around the main copper tailings was determined. The study will provide further insight into the extent of the contamination in these areas exhibiting high visible contamination and potentially high impacts. Sampling was carried out in November 2008, April 2011 and November 2011. A total of 135 leaf samples from three tree species (Lonchocarpus capassa, Colophospermum mopane and Euclea divinorum) were analysed, of which 74 samples were from the smelter plume deposition area, 51 samples were from the main copper tailings seepage area and 10 were leaf litter samples. Elemental concentrations in the leaves were measured and total percentages of C, H, N and S were determined. The highest concentrations of elements were found in the leaf litter samples from the smelter plume deposition area in 2008, with the average concentrations being: 1.57 ug/g of Ni, 9.44 ug/g of Bi, 16.3 ug/g of Pb, 110 ug/g of Mn, 122 ug/g of Ti, 483 ug/g of Al, 1463 ug/g of Cu, 2812 ug/g of S and 5611 ug/g of Fe. Element concentrations in trees varied with the tree species, higher levels were found in L. capassa and E. divinorum leaves than in C. mopane leaves. In the leaves analysed from the smelter plume deposition area the element concentrations decreased in the order S > Fe > Al > Cu > Mn > Ti > Pb > Ni > Bi. In the leaves from the Cu tailings seepage area the element concentrations decreased in the order S > Fe > Mn > Cu > Al > Ti > Ni > Bi > Pb. Significant differences were observed for the concentrations of certain metals and elements in the leaves between the three years (2008 to 2011) and between seasons (April to November). The concentrations generally decreased from 2008 to 2011and from April to November 2011. The findings from this study indicate that both of the high impact areas investigated are contaminated by the mining activities, with trees growing in the smelter plume deposition area showing higher contamination than trees in the Cu tailings seepage area. The leaves and leaf litter sampled in this study can be used as bioindicators of the contamination in this region.
39

Mopane worms (Imbrasia belina) as indicators of elemental concentrations in a trophic system

Pillay, Sumeshni 20 January 2016 (has links)
A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, South Africa, in fulfilment of the requirements for the degree of Master of Science. August 2015 / The impacts of mining on the environment continue to pose a risk in many regions. Palabora Mining Company (PMC) situated in Limpopo Province, South Africa is of environmental interest because of its shared border with South Africa’s Kruger National Park. PMC generates both gaseous (emitted from the reverberator (Rev; also known as a smokestack)) and solid (stored in the tailings storage facility (TSF)) waste products. To assess possible pollution to the environment from PMC’s activities, two study species were chosen, the Anomalous Emperor Moth (Imbrasia belina [Westwood 1849] (Lepidoptera: Saturniidae)) and its primary host the mopane tree (Colophospermum mopane [Kirk ex Benth.]). In addition to these two species being abundant on and around PMC, the mopane moth and all stages of its lifecycle are a source of food to many animals, and mopane caterpillars are a valuable source of food and income to many people in this region. Mopane caterpillars and mopane leaves were collected from on and around PMC at varying distances from the reverberator and TSF, as well as from several control sites. The elemental contents of these samples were analysed for 25 elements, focusing on copper, iron, aluminium, silicon, arsenic, zinc, nickel, lead, mercury, chromium and cadmium. In addition to these elemental analyses, the carbon and nitrogen isotopic compositions of these samples as well as caterpillar headwidth, body mass and mandible wear were also measured to assess the impacts of elemental concentrations on caterpillar growth. No mopane caterpillars were found at the two reverberator sites closest to the reverberator itself. Overall these two reverberator sites appear to be most contaminated, as concentrations of 14 of the 25 elements measured were highest in the mopane leaves from these two sites. The copper concentrations at these two sites, 42 ppm and 29 ppm respectively, were at levels that are considered toxic to plants. Assuming that 10 mopane caterpillars (each weighing 5g) are consumed a day, copper concentrations in the mopane caterpillar bodies across sites (between 8 ppm and 12 ppm) would equate to a maximum of 0.56 mg.day-1, which is less than the recommended maximum intake level of 10 mg.day-1 suggested for humans. As there was little difference between sites in terms of leaf carbon and nitrogen composition, elemental concentrations do not appear to be affecting the nutritional content of the leaves. This would suggest that caterpillar growth is not affected by elemental concentrations at sites where they can survive. Similarly, caterpillar headwidths did not vary greatly between sites for each instar, suggesting that elemental concentrations are not affecting mopane caterpillar growth. Headwidths and mandible wear were found to be useful tools to age mopane caterpillars within an instar, and can be used in future to ascertain if mopane caterpillars are bioaccumulating elements or eliminating excess elements when they moult.
40

The use of biological indicators in assessing pollution status in selected rivers in Limpopo Province, South Africa

Nephale, Livhuwani Eva January 2020 (has links)
Thesis (M.Sc. (Aquaculture)) -- University of Limpopo, 2020 / The aim of the study was to assess the extent to which biological indicators and biomarkers can be used to monitor the pollution status of the Sand and Blood Rivers. Physico-chemical parameters were assessed as a primary approach in assessing pollution status of the Sand and Blood Rivers. Temperature, pH, dissolved oxygen (DO), biological oxygen demand (BOD), turbidity, total dissolved solids (TDS), total nitrogen, phosphorus and ammonia were assessed during the rainy and dry seasons. Physico-chemical parameters showed spatial and temporal variation. The hierarchical average linkage cluster analysis grouped the reference sites (S1 and B1) into one group and sites after points of discharge (B2, S2, S3, S4 and S5) into another group. This grouping was due to the pollution status of each site, with the reference sites less polluted than the sites downstream of the wastewater treatment plant effluent points of discharge. The canadian council of ministers of the environment water quality index (CCME WQI) categorized reference sites as good, whilst sites after points of discharge were categorized as poor. This shows that the Sand and Blood Rivers are degrading. Heavy metal contamination in water, sediment and grass from the Sand and Blood Rivers was evaluated during the rainy season and dry season. All assessed heavy metals (Cadmium, Chromium, Copper, Iron, Lead, Manganese, Nickel, and Zinc) were below the detection limit in water, with an exception for Iron and Manganese. All metals assessed were also below the probable effect levels (PEL) according to the CCME. Geo-accumulation Index showed that the Sand and Blood Rivers were not contaminated with heavy metals. The enrichment factor (EF) further showed that only site B2 was enriched with manganese from anthropogenic activities. Heavy metal assessment in Cyperus exaltatus showed that this grass is a poor candidate for phytoremediation. Macroinvertebrates were used as biological indicators to assess pollution status of the Sand and Blood Rivers. Macroinvertebrates were sampled according to South African scoring system (SASS) and identified using aquatic invertebrates of South African rivers field guide. The SASS and average score per taxon (ASPT) categorized all sampling sites as critically modified. The family-level biotic index (FBI) also showed that the Sand and vi Blood Rivers are enriched with organic pollution. The reference sites recorded high macroinvertebrates diversity, compared to the sites after points of discharge. All indices used showed spatial and temporal variation in the water quality of the Sand and Blood Rivers. The relationship between macroinvertebrates and physico-chemical parameters were explored with the use of canonical correspondence analysis (CCA). The CCA triplots showed that the reference sites were associated with pollution sensitive taxa, whilst pollution tolerant taxa were associated with sites after points of discharge. Moreover, sites after points of discharge strongly correlated with phosphorus, nitrogen, ammonia, BOD and TDS. Clarias gariepinus gills and liver histology were used as biomarkers in assessing pollution status in the Sand and Blood Rivers. Gills and liver samples were qualitatively and semi-quantitatively assessed. Fish from the reference sites had less gill lesions than fish from sites downstream. Alterations such as hyperplasia of interlamellar, fusion of secondary lamellae, epithelial lifting and hyperplasia of secondary lamellae were observed in fish collected from downstream. Fish from downstream also showed more liver alterations than fish from the reference sites. Alterations such as melano-macrophage centers (MMC), macrovesicular steatosis, sinusoid congested with kupffer cells, nuclei pleomorphism and vacuolation were identified in liver of fish from sites S4 and S5. This was further confirmed by the high gill and liver indices of fish from downstream. Acetylcholinesterase enzyme (AChE) enzyme in brain and lactate dehydrogenase (LDH) in liver of Clarias gariepinus were used as biomarkers in assessing pollution status of the Sand and Blood Rivers. Both AChE and LDH enzymes were lower on fish from downstream compared to fish from the reference sites. This shows that AChE and LDH enzymes on fish from downstream were inhibited. This was attributed to the use of pesticides on farms surrounding the Sand and Blood Rivers and also the discharge of poorly treated sewage effluent from the Polokwane and Seshego wastewater treatment plants (WWTP’s). The Sand and Blood Rivers are surrounded by farms that utilize pesticides in their practice. This study showed that biological indicators and biomarkers can be used to assess pollution status of the Sand and Blood Rivers. However, biological vii indicators and biomarkers should be used in concurrence with physico-chemical parameters. / Department of Agriculture Forestry and Fisheries, Water Research Commission (WRC) and Aquaculture Research Unit.

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