Philosophiae Doctor - PhD / Cape Town includes two vegetable farming areas within the city limits, the Joostenbergvlakte/Kraaifontein area and the Philippi area. Both areas supply produce to local markets and further afield. Sporadically, high levels of cadmium, copper, lead and zinc have been found to occur in some of the soils, irrigation water resources and crops. To find the sources of specifically Cd, Pb and Zn to these agricultural systems, extensive analysis of several heavy metals in inputs such as fertilizers, agrochemicals and supplementary water resources to these farming areas was undertaken. Heavy metal concentrations in soils, irrigation water resources and crops were also determined. Two mitigation techniques that could be used to remediate Cd, Pb and Zn contamination were investigated. The first mitigation method included immobilization of heavy metals as phosphate complexes by using a triple super phosphate fertilizer, while the second method involved mobilisation and thus leaching of heavy metals away from plant roots using EDTA. These mitigation methods were tested in a pot experiment using cabbage as the experimental crop and soil from these areas as growth medium. A survey of common farming practices in these two areas and farmers willingness to use remediation methods was conducted. / South Africa

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Thesis (MA)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Since Burundi gained independence in 1962, this country has experienced periods of mass communal violence. Extensive scholarly research has focused on exploring the factors behind, and the nature of, the conflicts in Burundi from a socio-ethnic perspective. There has, however, been a persistent lack of attention paid to the inextricable relationship between environmental factors; particularly the scarcity of resources, coupled with rapid population growth; and Burundi‘s recent history of internal conflict. Noteworthy explanatory factors, which are often ignored in literature on the environment and conflict, have thus motivated this study. Burundi is an example of this reality because of a highly dependent agricultural economy and a constant growing population. This study used a descriptive analysis, as methodological tool; in order to gain an understanding of Burundi‘s land question - that is, how limited access to land and the constantly increasing population have led to environmental degradation, that served as motivational trigger factors for the violent political conflicts that occurred at various periods between 1965 and 1993 in this country. This study addresses this epistemological gap. In order to explore the nexus between environmental factors, land access, population growth and the political conflicts in Burundi, this study draws and builds upon Jared Diamond‘s (2005) five point framework of potential trigger factors to environmental collapse. Moreover, Diamond‘s (2005) ecocide theory argues that there are eight specific indicators to demonstrate how societies undermine themselves by damaging their own environment; thus resulting in an ecocide. This theory was applied to the two main environmental variables examined in this study. More specifically, this theoretical perspective provided a base for exploring how land issues, population growth, environmental degradation and political change can be understood as important precursors to the violent conflicts in Burundi. What may be surmised by this study; is that there is indeed a positive correlation between these forces, where the values of the independent variables (land access and population growth) are associated with the values of the dependent variable (violent conflict). This correlation, therefore, calls for an acknowledgement of the complexity of the Burundian conflicts and that ethnicity which has dominated contemporary conflict analysis is but one of several social rifts. / AFRIKAANSE OPSOMMING: Sedert Burundi in 1962 onafhanklikheid verkry het, het hierdie land periodes van massa gewelddadige politieke konflik ervaar. Uitgebreide wetenskaplike navorsing het daarop gefokus om die faktore agter die gebeure, sowel as die aard van die konflik in Burundi vanuit ‘n sosio-etniese perspektief, te ondersoek. Tog word daar steeds gebrekkige aandag geskenk aan die onlosmaaklike verhouding tussen omgewingsfaktore, veral gebrek aan hulpbronne, gepaardgaande met die voortgesette bevolkingsaanwas; asook Burundi se onlangse geskiedenis van interne konflik. Noemenswaardige gapings, wat dikwels in die verklarende literatuur geïgnoreer word, het dus hierdie studie gemotiveer. Burundi is ‘n voorbeeld van hierdie werklikheid omdat die land baie afhanklik van landbou is; as gevolg van die kontstante bevolkingsaanwas in die land. Hierdie navorsing het beskrywende analise as ‘n metodologiese instrument gebruik om insig te kry oor Burundi se grondkwessie – met ander woorde hoe die beperkte toegang tot grond en ‘n toenemende bevolkingsaanwas gelei het tot die agteruitgang van die omgewing. Bostaande faktore het as motiverende sneller faktore gedien, wat aanleiding gegee het tot die gewelddadige politieke konflik, wat gedurende verskillende periodes tussen 1965 en 1993 in hierdie land ontstaan het. Hierdie studie poog dus om hierdie epistomologiese gaping aan te spreek. Ten einde die verband (nexus) tussen omgewingsfaktore, grondbesit, bevolkingsaanwas en die politieke konflikte in Burundi te ondersoek, steun en bou hierdie studie voort op Jared Diamond (2005) se vyfpunt raamwerk van potensiële sneller faktore, wat lei tot omgewings ineenstorting. Verder beweer Diamond (2005) se omgewings uitwissing (ecocide) teorie dat daar agt spesifieke aanduidings is om te demonstreer hoe gemeenskappe hulself ondermyn deur hul eie omgewing te beskadig/vernietig: wat uitloop op omgewings uitwissing (ecocide). Hierdie teorie is aangewend in die twee hoof omgewings veranderlikes, wat in die studie/ navorsing ondersoek is. Hierdie teoretiese perspektief het ook spesifiek ‘n basis voorsien om te ondersoek hoe grondkwessies, bevolkingsaanwas, omgewings agteruitgang en politieke verandering verstaan kan word as belangrike aanwysers van die geweldadige konflik in Burundi. Deur middel van hierdie studie kan ‘n duidelike opsomming gemaak word dat daar inderdaad ‘n positiewe korrelasie tussen hierdie magte voorkom, waar die waardes van die onafhanklike veranderlike (toegang tot grond en bevolkingsgroei) geassosieer word met die waardes van die afhanklike veranderlike (geweldadige konflik). Hierdie korrelasie verg dus ‘n beroep om erkenning te gee aan die kompleksiteit van konflik in Burundi. Hierdie etniese debat, wat tans die oorheersende konflik aanvuur, is maar net een van die verskeie interpretasies van sosiale breekpunte in Burundi is.