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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.
1

Environmental risk assessment of inorganic and organic pollutants in raw and cooked food in African countries

Nuapia, Yannick Belo 19 September 2016 (has links)
A dissertation submitted to the Faculty of Science, University of the Witwatersrand in fulfilment of the requirements for the degree of Master of Science. Johannesburg 2015 / Exposure to inorganic and organic pollutants residues causes negative effects to human health. They can cause damage to the living organism as well as to the environment. Humans take up these pollutants through skin absorption, respiration and ingestion of contaminated food and also the drinking water as a potential contaminants exposure route for inorganic and organic pollutants to humans. Studies have shown that inorganic and organic pollutants can be retained in food crops at higher than the permissible levels, thus posing some health risks to consumers. This study sought to assess the potential risk posed by inorganic and organic pollutants to human health as a result of consuming raw food and processed food cooked in traditional utensils. The food samples and the traditional utensils were collected in Kinshasa and Johannesburg markets. In total ninety- two food samples were assessed. The food crops included: cabbage, cassava, beans, beef meat and fish (tilapia). Ten trace elements, namely: Al, As, Cd, Cr, Cu, Hg, Mn, Pb, Se and Zn were analysed in raw food samples using ICP-OES, ICP-MS and mercury analyser. These metals were also analysed in food cooked with the traditional utensils. The health risk indices calculated were: Daily Intake of Metal (DIM) and Hazard Index (HI). The results obtained reveal that the raw food collected in Johannesburg markets contained a significant (p ˂ 0.05) higher concentration in all elements than the food samples collected in Kinshasa markets. Hg was detected only in fish samples. It was observed that cooking utensils can leach some significant quantities of trace elements into food during processing, hence resulting increase the concentration of these metals in processed foods. The DIM exceeded the oral reference dose (Rfd) and the HI were ˃ 1 in all the food cooked. The results of metal found in this current investigation were above the standard permissible limit set by FAO/WHO. On the other hand, the levels of 17 organochlorine pesticides were assessed in uncooked and cooked beans, cabbage, cassava, fish and beef meat collected in Kinshasa and Johannesburg markets. It was noticed from the results recorder that the mean concentration of organochlorine pesticides in uncooked food collected in Johannesburg market were significantly high (p ˂ 0.05) than the uncooked food from Kinshasa markets. DDE recorded its highest mean level (253.58±4.78 μg kg-1) in beef meat samples collected in Johannesburg markets. The results from the current study revealed that after cooking the amounts of organochlorines were significantly reduce than the uncooked food. Residue amounts of organochlorine pesticides found in this study are considerably lower than the recommended amount of organochlorines set by WHO/FAO (300 μg kg-1). / MT2016
2

Multi-Dimensional Drought Risk Assessment Based on Socio-Economic Vulnerabilities and Hydro-Climatological Factors

Ahmadalipour, Ali 30 November 2017 (has links)
Drought is among the costliest natural hazards developing slowly and affecting large areas, which imposes severe consequences on society and economy. Anthropogenic climate change is expected to exacerbate drought in various regions of the globe, making its associated socioeconomic impacts more severe. Such impacts are of higher concern in Africa, which is mainly characterized by arid climate and lacking infrastructure as well as social development. Furthermore, the continent is expected to experience vast population growth, which will make it more vulnerable to the adverse effects of drought. This study provides the first comprehensive multi-dimensional assessment of drought risk across the African continent as a function of hazard, vulnerability, and exposure. A multi-model and multi-scenario approach is employed to quantify drought hazard using the most recent ensemble of regional climate models and a multi-scalar drought index. Moreover, a rigorous framework is proposed and applied to assess drought vulnerability based on various sectors of economy, energy and infrastructure, health, land use, society, and water resources. Drought risk is then projected for different population scenarios and the changes of drought risk and the role of each component are investigated. In addition, the impacts of climate change on heat-stress mortality risk is assessed across the Middle East and North Africa. The results indicate vast increase for the projected drought risk with varied spatiotemporal patterns. Population growth and climate change will significantly escalate drought risk, especially in distant future. Therefore, climate change mitigation and adaptation planning as well as social development strategies should be carried out immediately in order to reduce the projected adverse risks on human life and society.
3

A model for evaluating risk in Africa : a mining perspective

Erasmus, Lourens J. 12 1900 (has links)
Thesis (MBA (Business Management))--Stellenbosch University, 2008. / AFRIKAANSE OPSOMMING: Suksesvolle eksplorasieprojekte en die daaropvolgende mynboubedrywighede kan as die stimulus dien vir ekonomiese groei in Suider Afrika deur middel van werkskepping, beter lewensomstandighede, en uiteindelik ekonomiese en polilieke stabilileit. Mynbou het die vermoe om dit te bewerkstellig. Die doel is om uiteindelik 'n langtermyn, veilige, vredevolle en vooruitstrewende oplossing vir die streek te vind, wat volgehoue groei gebaseer op 'n ekonomiese opbloei veroorsaak deur die implementering van suksesvolle mynbouprojekte en vooruitstrrewendheid tot gevolg het. Om dit reg te kry, is 'n deeglike en volledige studie betreffende alle moontlike risiko's, polities, ekonomies en sosiaal, wat sulke bedrywighede kan beinvloed, noodsaaklik. Ongelukkig ly die streek aan 'n gebrek aan buitelandse vaste investering as gevolg van burokrasie, politieke onstabiliteit en 'n onsekere veiligheidsituasie. Die hoof doel van hierdie studie is om 'n model daar te stel wat gebruik kan word om 'n voorlopige ontleding van 'n land se risikofaklore aangaande die algemene besigheids- en beleggingsklimaat te doen, soos gesien uit die oogpunt van beleggers in eksplorasie en mynbouprojekte. Angola en Zimbabwe, waar mynbou 'n groot rol kan speel, is geidentifiseer op die basis van die kwalitiet van hul mineraalafsettings en mynboupotensiaal. Deur gebruik te maak van die model wat in hierdie studie ontwikkel is waar gradering berus op 'Politieke', 'Finansiele', 'Sosiale Risiko', asook 'Eienaarsrisiko' onderskeidelik, gradeer Angola as 'n CBCB land met 'n matig stabiele omgewing om eksplorasie en mynbouprojekte van stapel te stuur. Dit is 'n land met uitgebreide minerale moontlikhede en alhoewel die infrastruktuur op hierdie stadium te kort skiet, het die land drie groot hawens. Geen groot bedreigings of destabiliserende faktore bestaan op die kort- tot medium termyn nie. Dit het die vermoe om tot 'n BBCB status oor die medium- tot lang termyn te beweeg. Zimbabwe verwerf 'n gradering van DDC+C, wat dui op 'n hoogs riskante omgewing om eksplorasie en mynbouprojekle van stapel te stuur. Niemand is seker wat die huidige verkiesing en die toekomstige politieke bedeling sal voortbring nie. Die huidige situasie kan amper net verbeter vir die land en sy mense met die moontlikheid van 'n regering van nasionale eenheid. Alhoewel die land dalk nog nie sy onderste draaipunt bereik het nie, kan 'n gradering van CC+C+C+ 'n moontlikheid oor die medium termyn wees, en selfs beter op die langtermyn. In 'n land met enorme minerale moontlikhede het die tyd aangebreek om te begin soek na geskikte gebiede vir eksplorasie doeleindes. Zimbabwe het die potensiaal om weer Afrika se kosmandjie te word met ondersteuning van die mynboukant. 'n Regverdige demokratiesverkose regering en baie harde werk, toewyding en deursettingsvermoe is nodig om uiteidelik te seevier. Laastens, die belangrikste deel van die risikobepaling van 'n land kom in die vorm van politieke risiko, en meer spesifiek, "leiersrisiko". Ongelukkig is die grootste struikelblok in langtermyn-vooruitskatting die feit dat die status quo vir die volgende dekade geldig kan bly, of amper oornag omvergegooi kan word. Dit kan weer lei tot 'n kettingreaksie reg deur al die sfere van die politieke en sosioekonomiese orde, binne en soms selfs buite die land in die vorm van binnelandse oproerigheid en buitelandse sanksies of ondersteuning. 'n Gevoel van dringendheid om te verander tot voordeel van almal, moet egter nog posvat. Die son wag nie vir Afrika nie. / ENGLISH ABSTRACT: Successful exploration projects and subsequent mining ventures can provide the stimulus for economic growth in Southern Africa through job creation, improved living conditions, and eventually economic and political stability. The aim is to ultimately ensure a long- term, safe, peaceful and prosperous solution for the region consisting of continuous growth and prosperity based upon an economic kickoff sparked by the implementation of successful mining projects. To achieve this, a thorough and comprehensive study of all possible risks, political, economic and social affecting such ventures is of the utmost importance. Unfortunately, the region suffers from a lack of foreign direct investment to make this happen largely as a result of bureaucracy, political instability and an uncertain security situation. The main aim of this study is to create a model for an initial risk analysis by analysing a country's risk factors relevant to the overall business and investment climate as perceived by investors in exploration and mining projects. Two countries, Angola and Zimbabwe, where mining can play a large role have been identified based on the quality of their mineral deposits and mining potential. Using the model developed in this research study where grading is based on 'Political', 'Financial (Transfer)', 'Social', and 'Ownership Risk' respectively, Angola rates a CBCB country with a moderately stable environment in which to launch exploration and mining ventures. It is a country with a vast mineral potential and although the support infrastructure is lacking at this stage, have three major ports. No major threats or destabilising factors exist in the near to medium terms. It has the ability to change to a BBCB status over the medium to long term. Zimbabwe receives a rating of DDC+C with a highly risky environment to launch exploration and mining ventures. No one is sure what the last election and the future political framework will bring. The current status can almost only improve for the country and its people with the possibility of a government of national unity. Although the country might not have reached the bottom turning point yet, a CC+C+C+ rating could be a possibility over the medium term and even better over the long term. In a country with enormous mineral potential, it is time to start scouting for promising regions for exploration purposes. Zimbabwe has the potential to again become the bread basket of Africa with backup from the mining industry. A proper democratically elected government and much hard work, commitment and dedication are necessary to be successful eventually. Finally, the most important/crucial part of measuring the risk associated with a country comes in the form of political risk and more precisely, sovereign risk. Unfortunately, and this is the main stumbling block in long-term forecasting, the status quo can continue for the next decade, or be turned upside down almost overnight. This in turn can lead to a chain reaction throughout all spheres of the political and socioeconomic standing, inside and outside the country in the form of domestic upheaval and foreign sanctions or support. A sense of urgency to change for the better still has to emerge though. The sun doesn't wait for Africa.
4

Measuring household resilience in developing countries : evidence from six African countries.

Browne, Michelle. January 2011 (has links)
In this study, a household resilience score was developed as a measure of rural household resilience to identify households with low resilience and to measure progress towards improved household resilience. Resilience is the ability of households to cope with risk. The motivation for the study originated from the first objective of the Framework of African Food Security (FAFS) of improved household risk management, and the indicator of progress towards this objective – proposed by the FAFS - a resilience score. A review of the literature indicated that the assets owned by a household could be used as a proxy for resilience. The household component of the Demographic and Health Surveys for six African countries was used to develop and apply the resilience score. The score was estimated using an index of assets owned by the household and information regarding household access to certain services and characteristics of the dwelling. There is disagreement in the literature concerning the best method of constructing an asset index in terms of how to weight the variables included in the index. As a result, four methods of constructing an index of socio-economic status (SES) were selected for comparison in this study: two linear principal component analysis (PCA) techniques; a non-linear or categorical principal component analysis (CATPCA) method; and a simple sum of assets technique. The results from the application of each of the four indices to the country data and the resulting classification of households into quintiles of SES were compared across several assessment criteria. No single method out-performed the others across all the assessment criteria. However, the CATPCA method performed better in terms of the proportion of variance explained by the first principal component and the stability of the solution. The results showed that for all methods, SES was not evenly distributed across the sample populations for the countries analysed. This violates the assumption of uniformity implied when using quintiles as classification cut-off points. As an alternate to the quintile split cluster analysis was applied to the SES scores derived for each country. The classification of households into SES groups was repeated using k-means cluster analysis of the household SES scores estimated by the CATPCA method for each country. The results showed that a greater proportion of households fell into relatively lower levels of SES, which is in contrast to the assumption of uniformity of SES made when using the quintile cut-off approach. Cluster analysis better reflected the clustered nature of the household data analysed in this study, compared to the quintile cut-off method. In a final analysis, the index of SES along with k-means cluster analysis was applied to household data from two different time periods for five African countries to determine whether the resilience measure was able to detect changes in household SES between the two periods and, therefore, whether the tool could be used to monitor changes in household resilience over time. The results showed evidence of adjustments in SES over time: there were differences in the per cent of households allocated to the clusters of SES between the two periods. Using the CATPCA index and k-means cluster analysis, Egypt, Uganda and Mali showed an increase in the per cent of 'poor' households, while for Kenya and Tanzania there was a reduction in the per cent of households allocated to the first cluster between time periods: the decrease for Kenya from 2003 to 2008 was as much as 13 percentage points. The observed changes in SES were then compared to changes in national poverty estimates reported in the literature. The resilience score developed in the study displayed an ability to track changes in household SES over time and could be used as a measure of progress towards improved household resilience. As such, the resilience measure could be valuable to policy-makers for monitoring the impacts of policies aimed at improving household resilience. Future research is recommended before the reliability of the resilience measure developed here can be fully ascertained. / Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2011.

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