The purpose of this paper is to use the consumption models from industrialized countries to analyze China¡¦s urban and rural consumers. Consumption models will be discussed by analyzing the model framework and through empirical studies. The objective of this research is to find whether consumption models from industrialized countries are suitable for China¡¦s consumer and whether they can analyze the essential factors affecting consumer behavior in different external environments. This paper has found that: (1) Some of the essential elements of the western consumption model are not compatible with China¡¦s situation due to fundamental systemic and economic differences, although there are still some elements of the model which can still be applicable to China. (2) The government¡¦s fiduciary loan policy, reform of the social security system, degree of income stability and gauge of liquidity constraints are the main factors causing different consumer behavior in urban and rural Chinese consumers.

Economic theories usually assume that the amount of work offered by individuals increase as wages and salaries increase. However, there are volunteers who present their work without payment for the production of goods and services, for the benefit of others. Volunteer work is of significance in a time when social safety nets are weak and there are ever increasing demands on welfare organisations. Volunteers can make a difference in their communities and entire society in general which means that if they are understood better, it may be possible to harness their power for the greater good. Therefore, this thesis analyses volunteers and volunteerism in South Africa and the factors that determine their efforts. The manuscript presents a critical discussion of economic theories of volunteering, major concepts and types of volunteers to arrive at a plausible set of models explaining volunteerism and the general motives of volunteers. The descriptive analysis of data sets from the Labour Force Survey was conducted. The data also allows for the estimation of a limited dependent variable regression model of the probability of volunteering as a function of individual-specific predictors. The results from Logit (Binary LogitRegression) regression showed that all estimated coefficients have the expected signs: Females are more likely to do volunteer work more than males; older people are more likely to participate more in volunteer activities than middle age and younger ones. The results also reveal that the higher your level of education, the more likely you will be to do volunteer work. This was the same with income: higher income individuals are more likely to do volunteer work. This study also used data from the Volunteer Activities Survey (VAS) to describe volunteers and estimate a model of the determinants of hours of volunteer work supplied. The results indicate a robust relationships between volunteered and determinant such as gender, age group; population group, level of education, income category, marital status and employment status, to mention few. Results from the regression model show that age is positively related to hours spend doing volunteer work. Even though the gender variable is found to be not statistically significant, the results indicated that women do volunteer work more than men. The further a person is educated the more he/she will participate in voluntary work. The evidence indicated that there is a positive relationship between income and hours of volunteering. The evidence provides a number of findings that are important to policymakers, non-profit organisations and all other stakeholders in volunteerism. This study could be used to devise more efficient and effective plans of how the number of volunteers and the hours that they volunteer could be retained and increased. / PhD (Economics), North-West University, Potchefstroom Campus, 2014

Economic theories usually assume that the amount of work offered by individuals increase as wages and salaries increase. However, there are volunteers who present their work without payment for the production of goods and services, for the benefit of others. Volunteer work is of significance in a time when social safety nets are weak and there are ever increasing demands on welfare organisations. Volunteers can make a difference in their communities and entire society in general which means that if they are understood better, it may be possible to harness their power for the greater good. Therefore, this thesis analyses volunteers and volunteerism in South Africa and the factors that determine their efforts. The manuscript presents a critical discussion of economic theories of volunteering, major concepts and types of volunteers to arrive at a plausible set of models explaining volunteerism and the general motives of volunteers. The descriptive analysis of data sets from the Labour Force Survey was conducted. The data also allows for the estimation of a limited dependent variable regression model of the probability of volunteering as a function of individual-specific predictors. The results from Logit (Binary LogitRegression) regression showed that all estimated coefficients have the expected signs: Females are more likely to do volunteer work more than males; older people are more likely to participate more in volunteer activities than middle age and younger ones. The results also reveal that the higher your level of education, the more likely you will be to do volunteer work. This was the same with income: higher income individuals are more likely to do volunteer work. This study also used data from the Volunteer Activities Survey (VAS) to describe volunteers and estimate a model of the determinants of hours of volunteer work supplied. The results indicate a robust relationships between volunteered and determinant such as gender, age group; population group, level of education, income category, marital status and employment status, to mention few. Results from the regression model show that age is positively related to hours spend doing volunteer work. Even though the gender variable is found to be not statistically significant, the results indicated that women do volunteer work more than men. The further a person is educated the more he/she will participate in voluntary work. The evidence indicated that there is a positive relationship between income and hours of volunteering. The evidence provides a number of findings that are important to policymakers, non-profit organisations and all other stakeholders in volunteerism. This study could be used to devise more efficient and effective plans of how the number of volunteers and the hours that they volunteer could be retained and increased. / PhD (Economics), North-West University, Potchefstroom Campus, 2014

Wireless access networks today consume 0.5 percent of the global energy. Rapidly growing demand for new services and ubiqutious connectivity, will further increase the energy consumption. This situation imposes a big challenge for mobile operators not only due to soaring cost of energy, but also increasing concern for global warming and sustainable development. This thesis focuses on the energy efficiency issue at the system level and studies how to incorporate energy-awareness into the design of future wireless access networks. The main contributions have been given in the areas of energy efficiency assessment, architectural and operational solutions, and total cost of investment analysis. The precise evaluation of energy efficiency is the first essential step to determine optimized solutions where metrics and models constitute the two key elements.We show that maximizing energy efficiency is not always equivalent to minimizing energy consumption which is one of the main reasons behind the presented contradictory and disputable conclusions in the literature. Further we indicate that in order to avoid the debatable directions, energy efficient network design problems should be formulated with well defined coverage and capacity requirements. Moreover, we propose novel backhaul power consumption models considering various technology and architectural options relevant for urban and rural environments and show that backhaul will potentially become a bottleneck in future ultra-high capacity wireless access networks. Second, we focus on clean-slate network deployment solutions satisfying different quality of service requirements in a more energy efficient manner. We identify that the ratio between idle- and transmit power dependent power consumption of a base station as well as the network capacity requirement are the two key parameters that affect the energy-optimum design.While results show that macro cellular systems are the most energy efficient solution for moderate average traffic density, Hetnet solutions prevail homogeneous deployment due to their ability to increase the capacity with a relatively lower energy consumption and thus enable significant energy savings in medium and high capacity demand regions. Moreover, we investigate the energy saving potential of short-term energy aware management approach, i.e., cell DTX, taking advantage of low resource utilization in the current networks arising from strict QoS requirements. With the help of developed novel quantitative method, we show that Cell DTX brings striking reduction in energy consumption and further savings are achievable if the networks are designed taking into account the fact that network deployment and operation are closely related. Finally, we develop a general framework for investigating the main cost elements and for evaluating the viability of energy efficient solutions.We first reveal the strong positive impact of spectrum on both energy and infrastructure cost and further indicate that applying sustainable solutions might also bring total cost reduction, but the viability highly depends on unit cost values as well as the indirect cost benefits of energy efficiency. Results obtained in this dissertation might provide guidelines for the network designers to achieve future high-capacity and sustainable wireless access networks. / <p>QC 20140505</p>

Listeriosis caused by Listeria monocytogenes (L. monocytogenes) has been of public concern since the 1980s. Among all the RTE food, deli meats are the major carrier for this pathogen. Eliminating or lowering the initial level of L. monocytogenes in RTE meat and poultry product in the plants is an important practice in reducing the risk of L. monocytogenes to the public due to the growth potential of L. monocytogenes in the RTE food product during storage. Research identifying the contamination at plants provided information for the Food Safety and Inspection Service (FSIS) to establish the Interim Final Rule, requiring the food processing plants that produce post-lethality exposed RTE meat and poultry product choose one of the three alternative plans to ensure good sanitation conditions during food processing or suppress the growth of L. monocytogenes during storage: post-processing treatment and use of growth inhibitor (Alternative1), post-processing alone (Alternative 2a) or use of growth inhibitor and sanitation program (Alternative 2b), and sanitation program alone (Alternative 3). This research developed a comprehensive model that simulated the entire processes of RTE food production, taking into account potential transfer and growth of L. monocytogenes in RTE meat and poultry products. This plant-to-consumption model analyzed the effectiveness of the three alternative processes on reducing the L. monocytogenes in the RTE food products and also investigated the optimal sampling and sanitizing program. Results showed that formulation of food products with growth inhibitor has the greatest impact on reducing the risk of L. monocytogenes, followed by the post-processing treatment and sanitation intervention. Risk can also be reduced depending on alternatives. For example, 70% reduction if all are switched to alternative 2b and 91% reduction if all are switched to Alternative 1, compared with the current alternative selection by food establishments. This study investigated several important factors in the sanitation program, analyzed the sensitivities of these factors, and proposed the reasonable improvement of the hold-and-test strategies by the plant-to-consumer mathematic model. Holding all the lots during the food contact surface (FCS) testing period instead of holding lots after finding the positive FCS would increase the detection rate of positive lots by three "times. These results may help the food establishments under Alternative 3 choosing the proper sampling and sanitation program or switching to Alternative 1 or 2. / Ph. D.

Consumption-based asset pricing models (CCAPMs) connect asset returns with consumption growth. The poor empirical performance of early consumption models has led to the development of a number of more sophisticated models. Nevertheless, most models focus on the US markets, and very few CCAPMs have been examined in the Australian context. Given the importance of CCAPMs, the purpose of this thesis is to examine the connections between asset returns in the Australian market and consumption variables. The thesis also extends the analysis to examine CCAPMs in an international setting. There are four essays in this thesis. The first essay undertakes a thorough investigation of the empirical support for consumption-based asset pricing models in the context of several major Australian asset classes. Using the generalised method of moments (GMM) econometric approach, my study begins with the classic CCAPM originally tested by Hansen and Singleton (1982, 1983). The empirical analysis is then extended to test more-recent specifications of the CCAPM, including the habit-formation models of Abel (1990) and Campbell and Cochrane (2000), and the time nonseparable model of Epstein and Zin (1991). For each of the models examined, the results provide cautious support for the CCAPM especially in relation to equity returns. Size-sorted portfolios (in particular, portfolios of small stocks) and fixed-income returns cause the CCAPM restriction to be rejected. It also presents results that raise questions over the benefits from extensions of the classic CCAPM, such as habit-persistence and recursive utility models. The second essay studies the empirical performance of a linearised version of the classic CCAPM in the Australian market. The studies of Faff and Oliver (1998) and Faff (1998) are extended by employing more recent data and examining 25 size/BM portfolios as well as industry portfolios. It is found that by using the lagged portfolio returns, the linearised CCAPM for both industry portfolios and 25 size/BM portfolios is generally not rejected. The third essay empirically examines conditional CCAPMs where the conditioning variables are consumption factors such as the consumption-wealth ratio proposed by Lettau and Ludvigson (2001a, 2001b), the surplus consumption ratio (Campbell and Cochrane, 1999), and the labour income to consumption ratio (Santos and Veronesi, 2006). Here long-horizon return predictability tests are conducted using these factors and cross-sectional tests on whether these factors are priced using both 25 Size/BM portfolios and industry portfolios. Utilising the Fama-MacBeth (1973) procedure, it is found that conditional models perform better than unconditional models. However, these conditional models do not outperform the Fama-French three-factor model. The fourth essay tests the world CCAPMs. Using data for 17 countries, the following are tested: the classic world CCAPM under the assumption of complete international markets integration, the heterogeneous world CCAPM under the framework of Constantinides and Duffie (1996) and the world habit models. The finding here is that a large risk aversion is needed to resolve the equity premium puzzle for the classic world CCAPM; however, adding a cross-country consumption dispersion factor into the model significantly lowers the coefficients of consumption risk aversion. Unconditional linear factor models are also studied where it is found that the world consumption growth and the dispersion of the cross-sectional consumption growth provide some explanatory basis for the variation in the cross section of excess stock returns. More sophisticated consumption models perform better than the classic world CCAPM. This thesis makes a worthwhile contribution to the research literature on CCAPMs in Australia which up to now has been limited. It performs out-of-sample tests of major CCAPMs utilising several Australian asset classes. It not only provides some insights into the return predictability of the aggregate market index in Australia, but also presents some evidence of the explanation of the cross section of stock returns using consumption variables. Further, this thesis adds to the understanding of the

Bakgrund: Konsumtionen av alkohol har i stort minskat i hela västvärlden, denna nedåtgående trend är extra tydlig bland ungdomar. Fler och fler ungdomar konsumerar mindre och många väljer att helt avstå från att konsumera alkohol. Denna trend är förstås positiv på många sätt men väcker även frågor om hur och varför denna trend uppkommit. Samtidigt som konsumtionen av alkohol har minskat har studier visats att vissa former av narkotika blir vanligare och har därmed skapat teorin om ett eventuellt samband. Syfte: Syftet med denna studie är att analysera ungdomars minskade alkoholkonsumtion och koppla detta till eventuell ökning eller minskning i brukandet av narkotika bland de som inte konsumerar, konsumerar måttligt samt de som konsumerar mycket alkohol. Metod: Studiepopulationen består av 71 852 ungdomar i åldern 15-16 år från hela Sverige. Studien är en upprepad tvärsnittsstudie med data från åren 2001 till 2014. Den insamlade data analyseras med hjälp av flera logistiska regressioner. Resultat: Resultatet visar att de ungdomar som inte konsumerar alkohol inte använder narkotika eller cannabis i större utsträckning, de som konsumerar måttligt och konsumerar mycket använder dock narkotika och cannabis i större utsträckning. Slutsats: Sambandet mellan narkotika- och cannabisanvändandet och de ungdomar som konsumerar måttligt och mycket kan stärkas. Normalitetsprincipens hypotes att vid tider med låg totalkonsumtion av alkohol är det de som konsumerar mycket som använder narkotika och cannabis stärks av resultatet. / Background: Consumption of alcohol has declined substantially throughout the western world, this downward trend is extra clear among adolescents. More and more adolescents drink less and many choose to completely refrain from consuming alcohol. This trend is of course positive in many ways but also raises questions about how and why this trend has arisen. While alcohol consumption has decreased, studies have shown that certain forms of drugs are common and have thus created the theory of a possible connection. Aims: The purpose of this study is to analyze adolescents reduced alcohol consumption and link this to any increase or decrease in the use of narcotics among those who do not drink, drink moderately, and those who drink a lot. Methods: The study population consists of 71 852 adolescents aged 15-16 years from all over Sweden. The study is a repeated cross-sectional study with data from 2001 to 2014. The collected data is analyzed using multiple logistic regressions as well as an interaction regression. Results: The results show that the non-drinking adolescents do not use drugs or cannabis to a greater extent, but those who drink moderately and drink a lot, use narcotics as well as cannabis in greater extent. Conclusions: The relationship between narcotics/cannabis use and the adolescents who drink moderately and heavy can be strengthened. The results are consistent with the principle of normality which shows that at times with low total consumption of alcohol the heavy consumers of alcohol use more narcotics and cannabis.

The need for energy efficiency in wireless communication is prevalent in all areas, but to an even greater extent in low-power and lossy networks that rely on resource-constrained devices. This degree project seeks to address the problem of modelling the battery lifetime of a duty-cycled node, participating in a wireless sensor network that is typically used in smart home and building applications. Modelling in MATLAB combined with experimentation are employed to predict the life expectancy and to validate using a hardware implementation. Various scenarios including sleepy end devices in a wireless sensor network are modelled and validated; these range from variable wake-up frequency and packet payload transmission to increasing network contention with the addition of network load. A comprehensive analysis of the main factors contributing to wasteful energy usage is provided in this thesis project, and it can be concluded that the model can estimate the battery lifetime under different testing scenarios with an error less than 5 %. / Det finns ett stort behov av energieffektivitet inom trådlös kommunikation, särskilt inom nätverk med bortfall och låg strömförbrukning där resursbegränsade enheter nyttjas. Det här examensarbetet eftersträvar att lösa problemet med att modellera batterilivslängden hos en sensoranordning med en låg driftcykel, som en del av ett trådlöst sensornätverk avsett för att tillämpas i smarta hus och byggnader. Modellering i MATLAB kombinerat med experimentering används för att förutsäga den förväntade livslängden samt för att validera en hårdvaruimplementering. Flertalet scenarier med sovande noder modelleras och valideras, med allt från variabel uppvakningsfrekvens och paketöverföring till ökande resurskonflikter med ytterligare belastning på nätverket. I detta examensprojekt inkluderas en heltäckande analys av huvudorsakerna till energislöseriet hos enheterna och slutsatsen kan dras att modellen kan beräkna batterilivslängden för olika testscenarier med mindre än 5 % fel.

[ES] El Reino de Arabia Saudí está experimentando un importante crecimiento económico, industrial, comercial y demográfico. Este crecimiento, a su vez, provoca un aumento de la demanda de agua en la región. Además del crecimiento demográfico, también la industrialización y la modernización han ejercido una presión cada vez mayor sobre las infraestructuras hídricas del país. Urge aumentar la disponibilidad de agua para satisfacer la demanda prevista y mantener la seguridad y fiabilidad de los sistemas hídricos. Por lo tanto, es imperativo encontrar soluciones que mejoren la eficiencia del sistema hídrico del país. Un elemento clave en este esfuerzo es comprender y clasificar cómo se consume el agua con sus microcomponentes dentro de varios segmentos. La tesis recopila conocimientos precisos sobre las pautas y tendencias del consumo municipal de agua para comprender mejor los patrones de consumo y los comportamientos de los consumidores, así como desarrollar estimaciones e hipótesis preliminares. De este modo, se impulsará el modelo de demanda de agua municipal en el país para que sea capaz de hacer frente a diferentes escenarios y limitaciones. El desarrollo del modelo municipal de demanda de agua ha mostrado la necesidad de disponer de datos estadísticos y de facturación del agua fiables. Éstos constituyen el punto de partida de la previsión y deben estar disponibles con una resolución suficientemente alta. El modelo aquí presentado proporciona un marco para que nuevos desarrollos futuros. Los resultados del análisis también determinarán los factores y categorías utilizados en el modelo. El modelo se centra en la demanda de agua no residencial. No obstante, se incluyen previsiones separadas para la categoría residencial a fin de permitir la extrapolación de los resultados y el análisis top-down para un enfoque más preciso de las previsiones y, también, para una mejor comprensión general de los comportamientos de consumo de agua de la población. / [CA] El Regne de l'Aràbia Saudita està experimentant un important creixement econòmic, industrial, comercial i demogràfic. Aquest creixement, al seu torn, provoca un augment de la demanda d'aigua a la regió. A més del creixement demogràfic, també la industrialització i la modernització han exercit una pressió cada vegada major sobre les infraestructures hídriques del país. Urgeix augmentar la disponibilitat d'aigua per a satisfer la demanda prevista i mantindre la seguretat i fiabilitat dels sistemes hídrics. Per tant, és imperatiu trobar solucions que milloren l'eficiència del sistema hídric del país. Un element clau en aquest esforç és comprendre i classificar com es consumeix l'aigua amb els seus microcomponents dins de diversos segments. La tesi recopila coneixements precisos sobre les pautes i tendències del consum municipal d'aigua per a comprendre millor els patrons de consum i els comportaments dels consumidors, així com desenvolupar estimacions i hipòtesis preliminars. D'aquesta manera, s'impulsarà el model de demanda d'aigua municipal al país perquè siga capaç de fer front a diferents escenaris i limitacions. El desenvolupament del model municipal de demanda d'aigua ha mostrat la necessitat de disposar de dades estadístiques i de facturació de l'aigua fiables. Aquests constitueixen el punt de partida de la previsió i han d'estar disponibles amb una resolució prou alta. El model ací presentat proporciona un marc perquè nous desenvolupaments futurs. Els resultats de l'anàlisi també determinaran els factors i categories utilitzats en el model. El model se centra en la demanda d'aigua no residencial. No obstant això, s'inclouen previsions separades per a la categoria residencial a fi de permetre l'extrapolació dels resultats i l'anàlisi *top-*down per a un enfocament més precís de les previsions i, també, per a una millor comprensió general dels comportaments de consum d'aigua de la població. / [EN] The Kingdom of Saudi Arabia is undergoing substantial economic, industrial, commercial, and population growth. This growth, in turn, leads to increased water demand in the region. In addition to population growth, industrialization and modernization have placed increasing pressure on KSA's water infrastructure. There is an urgent need to increase the water capacity to meet the projected demand and maintain the water systems' security and reliability. Therefore, it is imperative to find solutions that improve the efficiency of the Kingdom's water system. A key element in this effort is understanding and classifying how water is consumed with its micro-components within various segments. The thesis aims to collect precise knowledge about municipal water consumption patterns and trends to understand water consumption patterns and consumer behaviours better and develop preliminary estimates and assumptions. This will drive the municipal water demand model in KSA to be capable of dealing with different scenarios and constraints. The development of the municipal water demand model highlighted the need for reliable statistical and water billing data. These form the starting point of the forecast and need to be available at a high enough resolution. The model provides a framework for the required data to be built on further. The analysis results will also determine the drivers and categories used in the model. The model focuses on the non-Residential water demand. Still, separate forecasts are included for the residential category to enable the extrapolation of the results and downward analysis for a more accurate and cost-effective bottom-up approach to forecasting and an overall better understanding of the population's water consumption behaviours. / Alhudaithi, M. (2023). A Sectorial Analysis of Municipal Water Consumption and Management in Saudi Arabia [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/201553

The Wonderfonteinspruit (WFS) flows through the richest gold mining region in the world and has subsequently been exposed to the related pollution for more than a century. In order to determine the extent of mining related pollution in the WFS, sediment, water, soil, grass and cattle tissue samples were collected, analysed and compared from an experimental group and a control group. This study identified cobalt, nickel, zinc, selenium, cadmium, gold, lead and uranium as elements of interest by comparing sediment samples from the WFS and the Mooi River (MR) (which served as a control or background site). The cobalt concentration was found to be 16.37 times higher, the nickel concentration was 30.4 times higher, the copper concentration was 3.59 times higher, the zinc concentration was 103.49 times higher, the selenium concentration was 7.14 times higher, the cadmium concentration was 17.88 times higher, the gold concentration was 4.78 times higher, the lead concentration was 1.32 times higher and the uranium concentration was 375.78 times higher in the initial comparison with sediments from the MR. These results were all found to be significant. All these elements are by products of non-ferrous mining activities as was described in the literature review. The elevated concentrations of these elements, which were found in the streambed sediment of a site in the Lower-Wonderfonteinspruit, suggest that they could have resulted due to upstream gold mining activities. These gold mining activities were initiated more than a century ago and continue to this day. Analysis of the different particle size fractions (sand, silt and clay fractions) revealed that the highest elemental concentrations were found in the clay sized fractions. The clay sized fraction usually contains secondary soil minerals which have the ability to adsorb dissolved cations onto their surface areas. Further analysis revealed that the sand fraction of the WFS sediment contained a substantial concentration of cobalt, nickel, copper, zinc, lead and uranium which, upon initial inspection could not be explained. X-Ray Diffraction (XRD) analysis revealed that more than 90 % of the WFS sand, silt and clay fractions consisted of quartz, which was much higher than that of the MR. Due to the particle size of quartz, it generally dominates the sand and silt fractions, and finding it at levels above 90 % in the clay sized fraction is thought to be highly irregular. This could be explained by the extraction and processing of gold reefs from the goldfields in the catchment. The gold reefs consisted of quartz veins that were milled to a fine dust and pumped onto slime and sand dumps after the gold was extracted. The most abundant ore minerals found within these dumps were uraninite(UO2), brannerite (UO3Ti2O4), arsenopyrite (FeAsS), cobaltite (CoAsS), galena (PbS), pyrrhotite (FeS), gersdofite (NiAsS) and chromite (FeCr2O4), which contain some of the elements of interest. These dumps are either located in close proximity to the WFS or connected to the WFs via canals or pipelines. Erosion of these dumps would then introduce this finely milled quartz into the stream system. Therefore, the elements found in the sediment of the WFS were not only introduced to the system in the dissolved form, but also in the particulate form. The water samples that were collected from the experimental site (WFS) were found to exceed the cobalt, nickel, copper, zinc, selenium and cadmium concentrations ranges which are normally found in natural waters. In addition to this, the cadmium, lead and nickel concentration in the WFS water samples were found to occasionally exceed the target water quality ranges for livestock water as set by DWAF (1996). Water samples that were collected from the control group were found to exceed only the selenium concentration found in natural water sources as found by Crittenden et al., (2005). Cattle in the experimental group drink directly from the WFS and may stir up the sediment and thereby increasing the elemental concentrations within the water prior to ingestion. The target water quality ranges (TWQR) for livestock watering, as set by DWAF 1996, were exceeded by the average nickel and lead concentrations found in the disturbed WFS water samples. Although the elemental concentrations in the respective water samples were fairly low there was a definite practical significant difference between the WFS water and the MR water samples, as well as the disturbed WFS water and the MR water samples. The WFS water quality seemed to have a very large standard deviation which could serve as an indication that the elemental concentrations are highly variable over time. The elemental concentrations that were found in soil samples from the respective sites were compared to elemental concentrations found in normal agricultural soil as presented by Bergman (1992), which revealed the following results. The cobalt concentrations in the soil samples from the soil along WFS site, soil along MR site and irrigation MR site exceeded the agricultural threshold value. The nickel concentrations in the soil samples from the soil along WFS site, soil along MR site, wetland WFS and irrigation MR site exceeded the agricultural threshold value. The zinc concentrations in the soil samples from the soil along WFS site exceeded the agricultural threshold value. Copper, selenium, cadmium and lead concentrations did not exceed the agricultural threshold values in any of the respective sites. The agricultural threshold value for uranium concentrations was exceeded in the soil samples from the soil along the WFS site and the wetland WFS site. The comparison between the elemental concentrations that were found in the soil samples from the irrigated soil WFS site and the irrigated soil MR site revealed a practically significant difference for the copper, zinc and uranium concentrations. The comparison between the elemental concentrations found in soil samples from the soil along the WFS site and the soil along the MR site revealed a practically significant difference for all elements of interest. The analysis of the elemental concentration in the different particle size fractions of soil samples from all the sites (excluding the irrigated pastures) displayed highest elemental concentrations in the clay sized fraction. The elemental concentrations that were found in this fraction are generally considered to be available for plant uptake, as most of them are usually bound to the surface of secondary soil minerals. The sites with the highest concentration of plant available elements were found to be the soil along WFS site and the wetland WFS site. The elemental concentrations found in the grass samples from the respective sampling sites were compared to elemental concentrations that are normally found in grass pastures (Underwood & Suttle, 2001). The cobalt, nickel, copper and concentrations that were found in the grass samples from most of the sites in both the control and experimental groups were all found to exceed the concentration ranges found in natural pastures. The cadmium and zinc concentrations in the grass samples from the soil along WFS site were found to exceed the respective concentration ranges found in natural pastures. The normal uranium concentration found in irrigated or natural grasses could not be found in an extensive search. Dreesen et al. (1982) reported 0.16 mg/kg uranium in grasses and 1.8 mg/kg uranium in shrubs that grew on soil-covered tailings material. All the sites in the experimental group, including the control WFS site, drastically exceeded these concentrations, which may suggest that the grasses in the experimental sites have been exposed to elevated uranium concentrations. The grass samples with the highest average elemental concentrations were found in the soil along WFS site and irrigated soil WFS site. Lead was to be the only element of interest to have the highest concentration in grass samples from the irrigated soil WFS site. The irrigated soil WFS site portrayed significant transfer factors for nickel, copper, zinc, lead and uranium. This could serve as an indication that the grasses under irrigation in the WFS site absorb and accumulate the highest concentration of elements in respect to the soil concentrations found in the various sites. Therefore, the irrigation from the WFS has a profound effect on the nickel, copper, zinc, lead and uranium concentration in the grass samples under irrigation. The results obtained from the comparative analysis of the elemental concentration in grass samples from the irrigation WFS and irrigation MR sites revealed that all elemental concentrations except for that of zinc had a difference that was practically significant, with the uranium concentration having the largest effect size. The results obtained from the comparative analysis of the elemental concentration in grass samples from the soil along WFS and soil along MR sites revealed that all elemental concentrations had a difference that was practically significant uranium, nickel and zinc concentrations having the largest effect sizes. Considering that a large effect size is achieved at a value equal to or greater than 0.8, the uranium concentration therefore had a massive difference in both comparisons. The results obtained from the comparative analysis of the elemental concentration in grass samples from the wetland WFS and control WFS sites revealed that only the cobalt, nickel and uranium concentrations had differences that were practically significant, with the cobalt concentration having the largest effect size. The results obtained from the comparative analysis of the elemental concentration in the grass samples from the soil along WFS and control WFS sites revealed that all the elemental concentrations except for the lead concentration had a difference that was practically significant. The cobalt, nickel and zinc had the largest effect sizes. The elemental concentrations that were found in cattle liver, kidney and muscle tissue samples from both the experimental and control groups were compared to elemental concentrations normally found in cattle samples as found in Pulse (1994), ATSDR (2004), and ATSDR (2011). This comparison revealed the following results: The nickel, cadmium and lead concentration that were found in the cattle liver, kidney and muscle tissue samples from both the experimental and control groups were found to be within the ranges normally found in cattle. Cobalt concentrations found in the liver and muscle tissue samples of cattle from both the experimental and control groups exceeded the normal ranges, and the cobalt concentrations found in the kidney samples from the experimental group exceeded the normal range. The copper concentration found in the kidney samples from the cattle in the experimental group exceeded that of the normal concentration range. The zinc concentration found in the liver and kidney samples in the cattle from the experimental group, and the kidney samples from the cattle in the control group exceeded the normal range. The selenium concentration found in the liver, kidney and muscle tissue samples in the cattle from the experimental group, and the kidney samples from the cattle in the control group exceeded the normal range. The uranium concentration found in the liver, kidney and muscle tissue samples in the cattle from the experimental group exceeded the normal range. The comparison between cattle tissue samples from the experimental and control group revealed that nickel, zinc, selenium, lead and uranium concentrations all reveal a practically significant difference. Uranium, nickel and lead portrayed the largest differences between the two groups. The uranium concentration in the cattle samples from the experimental group was 126.75 times higher in the liver, 4350 times higher in the kidney, 47.75 times higher in the spleen, 31.6 times higher in the muscle tissue, 60 times higher in the bone and 129 times higher in the hair than that of the cattle samples from the control group. In addition to this, the uranium did not only accumulate in the predicted tissue samples (bone, liver and kidney), but also in the muscle tissue samples. The nickel concentrations in the cattle samples were all found to be higher in the experimental group, with liver 1.4 times higher, kidney 387.5 times higher, spleen 2.1 times higher, muscle tissue 2.8 times higher, bone 167.5 times higher and hair 76.5 times higher than that of the cattle samples from the control group. The lead concentrations found in the cattle samples from the experimental group were found to be 3.8 times higher in the liver, 17.3 times higher in the kidney, 3.3 times higher in the spleen, 3.2 times higher in the muscle tissue, 9 times higher in the bone and 12.2 times higher in the hair than the cattle samples from the control group. Furthermore, the study revealed that the major route of ingestion for all the elements of interest, excluding nickel and cobalt was via the ingestion of grass. The major route for nickel and cobalt ingestion was via soil ingestion. The elemental concentrations from water ingestion were found to be a less significant. It was shown that a predictive cattle consumption model was developed and calibrated from data gathered from a control and experimental group. Animal matter analysed for both groups were related to the cattle age of six years. Although good correlation between observed and simulated values was achieved, the exiting model fit is non-unique. To obtain a more precise model fit a similar dataset is required for both groups, but at a different age. The predictive model also showed that if only grass were to be used as input, there were no significant changes in the correlation between observed and simulated values. This has a huge advantage in terms of costs associated with laboratory analyses as the analysis of grass will be sufficient for using the model. A human health risk assessment was performed based on the results of the cattle consumption model. It was shown that no toxic risk exits for both the control and experimental groups if an intake rate of 0.13 kg of meat per day was assumed. Furthermore, Figure 6-11 clearly indicates that an intake rate of up to 0.38 kg of meat per day also has no toxic risk for both groups, which strongly suggests that there is no risk to the human food chain. The cattle grazing in the WFS appear to be in a good physical condition and according to the farmer; the reproduction rate is at desirable levels. Good farming practices would have also played a significant role to achieve this. / Thesis (MSc (Environmental Sciences))--North-West University, Potchefstroom Campus, 2012.