3. Electronic Theses and Dissertations (ETDs) - All submissions
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Item Inhalation human health risk assessment: case study of a South African international airport(2020) Dubazana, MakhosazanaThere has been an increase in public health concerns due to the impact of airport-related emissions on public and occupational health. Many studies have evaluated the potential health risk of a wide range of toxic pollutants within an airport. However, there has not been enough work done to analyse the potential human health impact of benzene, toluene, ethylbenzene, and xylene (BTEX), which occurs within airport environments in significant amounts. Besides, BTEX compounds are known to have a wide range of health impacts, where humans exposed to these compounds for an extended period or over their lifetime are known to develop symptoms such as wheezing and headaches, which are associated with the general effects of BTEX on the nervous system. Furthermore, benzene exposure is associated with the development of leukaemia. This study aimed to assess the human health risk of BTEX compounds on hypothetical subpopulations groups of residents living near a privately-owned South African airport chosen for this study as well as on-site employees. The study utilised the US EPA guidelines on Human Health Risk guide materials and methods. The results of the average ambient air emissions are 2.69, 7.43, 1.53, and 5.36 ug/m-3 for benzene, toluene, ethylbenzene, and xylene, respectively. The ambient emissions were higher during the winter sampling campaign, with total BTEX concentrations ranging from 13.93 to 44.36 ug/m-3. BTEX seasonal and spatial variations were evident: concentrations dispersed from the southwest (lowest concentrations) to the northeast (highest concentration) end in the autumn and winter. On the other hand, in spring and summer, there were emission hotspots on either side of the runway. The results of the final risk assessment displayed similar spatial distributions to benzene emission; the highest cancer risk is at the emissions hotspots at the airport drop-off area and parking. The cancer risk was above the US EPA guideline of 1 x 10-6 for all locations. The residential subpopulation groups have an average cancer risk of 6.44 x10-05, while on-site employees have an average cancer risk of 2.66 x 10-06. The results of the general health risk measured through the Hazard Quotient were below 1 for most subpopulation groups, excluding the subpopulation group younger than six months. With the prolific increase in air traffic transportation and the probable deterioration of air quality, the resultant associated health risk for populations in and around airports may intensify, which is a cause for concern and further investigationItem Assessment of BTEX concentrations on-board in-service public buses in Johannesburg, South Africa(2019-07) Mansoor, YusufExposures to BTEX compounds in indoor environments are of great concern as these compounds have been shown to negatively influence human health. For urban dwellers, a major part of the day is spent indoors within microenvironments such as offices, schools, homes and while commuting on-board vehicles. Of the different types of microenvironments, vehicle cabins have been shown to have the highest BTEX concentrations due to the vehicle being a source of emissions itself and due to its close proximity to other sources of emissions. This study specifically considers BTEX concentrations on-board public buses as these vehicles transport large numbers of people over various distances and that commuters frequently spend a considerable amounts of time commuting on-board these vehicles daily. The aim of this study was to determine the BTEX concentrations on-board in-service public buses travelling along major routes through Johannesburg during the off-peak and peak times and to determine the factors which might affect these concentrations. The factors which were specifically taken into consideration were on-board temperature and humidity, ventilation mode, passenger number and the characteristics of the travelled routes. Two sampling campaigns were conducted; one during the off-peak and another during the peak commute times. For each campaign, buses travelling along three different routes, representing major commuter routes, were sampled. A total of 21 and 42 samples were collected on-board the buses for the off-peak and peak campaign, respectively. An active sampling approach was taken using personal air sampling pumps attached to coconut charcoal sorbent tubes. iButtons were used to collect on-board temperature and humidity and a GPS was used to collect the route data. The charcoal tubes were prepared using solvent extraction and subsequently analysed using gas chromatography (time – of – flight) mass spectrometry. In addition, field blanks, lab and solvent blank samples were analysed as quality assurance measures during both campaigns. The mean BTEX concentrations measured during the off-peak and peak campaigns were Benzene - 24.39 μ/m3, Toluene - 85.88 μ/m3, Ethylbenzene - 4.80 μ/m3 and Xylene - 5.70 μ/m3 and Benzene- 28.19 μ/m3, Toluene - 9.85 μ/m3, Ethylbenzene - 2.94 μ/m3 and Xylene - 7.5 μ/m3, respectively. A significant difference (p > 0.05) was noted between the off-peak and peak toluene concentrations, while no significant differences were observed amongst the other BEX compounds between campaigns. The analysis of the BTEX concentrations along travelled routes returned a result indicating no significant differences (p < 0.05) between sampled routes for both campaigns; except for the ethylbenzene measured during the off-peak campaign which showed a significant difference (p < 0.05) between Routes A and C. With regards to the effects of ventilation mode, passenger number and on-board temperature and humidity, no discernible effects on BTEX concentrations could be observed from the data. Furthermore, the lab and field blank samples measured varied levels of BTEX concentration, which would suggest sample contamination, which introduced a level of uncertainty in deriving actual BTEX concentrations. In general, no definitive conclusions could be drawn from this study, regarding the BTEX concentrations on-board the buses during the off-peak and peak times, effects of travelled routes, passenger number and ventilation mode, potential sources of BTEX compounds and their interaction with the on-board temperature and humidity. However, given that a study of this nature has not been published in South Africa; the current study is of value in guiding future researchers as to the potential challenges and barriers that might be faced when conducting such a study. Furthermore, this study has the potential to stimulate interest in the field of in-vehicle emission testing with regards to not only buses and VOCs but other pollutants such as NOx, PM, and CO amongst a variety of vehicle types and across other microenvironments in general.Item Water management in the South African mining sector: the role of climate stress(2017) Lugalya, Marie MinayoWater including both abundance and scarcity are critical issues worldwide. Concerns are escalating across the globe as many nations are struggling to secure sufficient water (CDP, 2013). Water shortages and periods of abundance could be triggered by several factors either due to physical conditions (rainfall patterns, evaporation, and temperature) or management capacities (policies, regulation, maintenance and monitoring) (Faramarzi et al., 2013). Furthermore the rate at which environmental, social, economic and political systems are continuously shifting has further complicated this issue. Factors, such as overpopulation, inadequate governance, rapid industrial development, intensive agricultural farming and extreme weather conditions all have the potential to adversely influence existing water scarcity (Faramarzi et al., 2013). Similar to many developing countries, South Africa faces the predicament of sustaining growing populations and industrial developments whilst preserving the ecosystem (DEA, 2013). The country is particularly vulnerable to periods of excess and water scarcity due to its distinctive climatic conditions. South Africa is characterised by exceedingly variable to low rainfall patterns, decreased humidity and high air temperatures (Ziervogel et al., 2014). The combination of these climatic conditions causes high levels of evaporation resulting in reduced water availability (Ziervogel et al., 2014). Climate alone does not influence water supply, as water conditions are impeded by various socioeconomic challenges. The severity of water scarcity, for example, is further compounded by rising water demands and declining water quality within the country (DEA, 2013). Water is essential for several processes across various industries (including health care, pharmaceuticals, energy, retail, construction agriculture, manufacturing, food and beverages) all of which contribute towards a thriving economy (DEA, 2013). Therefore the impacts of water scarcity and abundance (for example, extreme flooding) could likely threaten all water-dependent industries, the consequence of which would be devastating throughout the country. [No abstract provided. Information taken from introduction]Item Investigating residents' perceptions of environmental health in informal settlements of South Africa: the case of Makause, Ekurhuleni Municipality(2015-04-30) James, NtandokabawoThe relationship between humanity and environment influences the health and quality of the environment. In turn, the state of the environment determines the quality of life that inhabitants are bound to live. Urbanization and shortage of housing among the economically deprived groups coupled with lack of affordable housing has encouraged formation of informal settlements in cities throughout South Africa. Poor environmental health conditions are characteristic of such settlements, and these conditions can be attested to numerous factors such as politics, policies as well as failure by local municipalities to strategically improve living conditions of the economically disadvantaged. Twenty years into the new democratic South Africa, communities in these informal settlements are still faced with environmental uncertainties, poor service delivery and forced removals. Authorities are failing to come up with strategies that counter the ever growing urban poor populations that often result from migration of poverty. Communities of these settlements are not homogenous, and thus they perceive their prevailing environmental health conditions differently depending on their world view. Makause informal settlement in Ekurhuleni Metropolitan Municipality (EMM) lack basic services such as sanitation, water and electricity, which compromise the environmental health of the area. Residents of this settlement have a history of staging marches in a quest to obtain basic services. Their protests have been intercepted by the heavy arm of the law in the form of South African Police Services. This has been tailored into many other factors that can inform perceptions of their prevailing environmental health. The focus of this dissertation is to investigate local environmental health perceptions in Makause informal settlement with attention to factors that inform these perceptions. Semi-structured interviews formed the major research method employed for this research with a random selection of interviewees from the settlement. The sample generally expressed dissatisfaction with their prevailing environmental health and living conditions. This points to the fact that the government is faced with a task to improve living conditions in informal settlements around the country.Item The impact of a visit to Lesotho Water and Sewage Authority (WASA) on learner's knowledge about community health(2012-01-19) Molahloe, Maretsepile RelebohileThere is an increasing adoption of outdoor visits in high schools in Lesotho and this study was done to find out what students learn about community health as they visit Lesotho Water and Sewage Authority (WASA). Eighty Form D (equivalent to grade 11 in South Africa) learners were the participants in this study. In order to capture students‘ learning a qualitative study was designed. The study used observations, questionnaire (n=80) and semi-structured interviews (n=8) with learners. The data was analyzed inductively and deductively in order to answer questions about knowledge changes as a result of a visit to WASA, and about the aspects of the visit that influence learners‘ knowledge about community health. Analysis of the questionnaire and the interviews revealed that learners greatly gained knowledge as a result of the visit to WASA while others developed misconception and others did not change their conceptions at all. The forms of conceptual change identified from learners responses were enrichment and conceptual capture. Learners realized that water purification is not a minute-made activity since there are several steps involved in water purification and that taps are not the main water sources. Learners also became aware that boiling water is not the only effective way of treating water instead other purifying stations like WASA can purify water suitable for domestic use. However, some learners believed that water that has been treated by the sewage plant is not suitable to be purified and used for domestic purpose. The observation analysis indicated that the physical facilities, displays, prior knowledge and participation during the visit are some of the aspects that influence learners‘ knowledge about community health. The realism of concepts communicated during the visit enhanced learners‘ ability to acquire knowledge about community health. The physical facilities such as the machinery at WASA provided the concrete evidence that water is drawn from the rivers therefore rivers are the main water sources. Visual displays contributed much in learners‘ ability to gain knowledge during the visit to WASA. It has also been found that although manipulation of objects was minimal, learners still gained information communicated during the visit. With the stated findings above, a visit to WASA enhance learner‘s ability to acquire information about community health.