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Each year, the urbanised population grows exponentially and due to this growth, cities are forced to expand beyond their manageable borders resulting in greater pressure on the surrounding urban environment. Many South African towns or cities are dependent on surface water for water supply. These resources are slowly being depleted and the dependence on groundwater resources is becoming increasingly important. Due to increased mining, industrial and agricultural activities in South Africa the surface water and groundwater environments have become vulnerable to contamination. This study aimed to develop a methodology in which the risks of urbanisation can be quantified. The conceptualisation and qualitative site impact and risk assessments focused on any environmental changes. The urban environment was sub-divided into three distinct areas and analysed separately in order to detect possible groundwater impacts of the water flowing through the urban area. Upstream river flow gauge chemistry by way of tri-linear grouping (piper diagram) of the major anions and cations showed already impacted water due to mining activities north of Potchefstroom. Uranium concentrations in the downstream surface water showed negligible impact as the concentrations remained within the relevant standards over time. Total coliform bacteria concentrations were found to be well above the acceptable levels and these high concentrations are an indicator of water purification inefficiency. Different qualitative risk assessment approaches i.e. the Environmental Risk Assessment method, Fuzzy Logic and the Depth to water, recharge, Aquifer media, Soil media, Topography, Impact of the vadose zone media and Conductivity of the aquifer (DRASTIC) approach risk assessments were compared and used to determine the most effective way to determine the most likely risks associated with urbanisation. Different modelling tools namely, analytical element modelling method (AEM) using the Visual AEM program, a finite difference numerical modelling method using Processing Modflow v.8 (PMWin) were evaluated, however due to insufficient data, an analytical approach had to be developed. This approach incorporated logical steps and associated processes to serve as a guide for future urban hydrogeological investigations. A case study (namely Potchefstroom) was used to test the developed methodology. The developed methodology provides a step by step approach to urban risk assessment, even in areas where there is insufficient data. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

Each year, the urbanised population grows exponentially and due to this growth, cities are forced to expand beyond their manageable borders resulting in greater pressure on the surrounding urban environment. Many South African towns or cities are dependent on surface water for water supply. These resources are slowly being depleted and the dependence on groundwater resources is becoming increasingly important. Due to increased mining, industrial and agricultural activities in South Africa the surface water and groundwater environments have become vulnerable to contamination. This study aimed to develop a methodology in which the risks of urbanisation can be quantified. The conceptualisation and qualitative site impact and risk assessments focused on any environmental changes. The urban environment was sub-divided into three distinct areas and analysed separately in order to detect possible groundwater impacts of the water flowing through the urban area. Upstream river flow gauge chemistry by way of tri-linear grouping (piper diagram) of the major anions and cations showed already impacted water due to mining activities north of Potchefstroom. Uranium concentrations in the downstream surface water showed negligible impact as the concentrations remained within the relevant standards over time. Total coliform bacteria concentrations were found to be well above the acceptable levels and these high concentrations are an indicator of water purification inefficiency. Different qualitative risk assessment approaches i.e. the Environmental Risk Assessment method, Fuzzy Logic and the Depth to water, recharge, Aquifer media, Soil media, Topography, Impact of the vadose zone media and Conductivity of the aquifer (DRASTIC) approach risk assessments were compared and used to determine the most effective way to determine the most likely risks associated with urbanisation. Different modelling tools namely, analytical element modelling method (AEM) using the Visual AEM program, a finite difference numerical modelling method using Processing Modflow v.8 (PMWin) were evaluated, however due to insufficient data, an analytical approach had to be developed. This approach incorporated logical steps and associated processes to serve as a guide for future urban hydrogeological investigations. A case study (namely Potchefstroom) was used to test the developed methodology. The developed methodology provides a step by step approach to urban risk assessment, even in areas where there is insufficient data. / MSc (Environmental Sciences), North-West University, Potchefstroom Campus, 2015

Master thesis. / Format: PDF. Bibl.

Spatial and temporal patterns of semi-volatile organic contaminant (SVOC) concentrations in air and precipitation were investigated at the urban scale in order to improve our understanding of emission sources and factors affecting intra-urban variability. Toronto, Canada was used as a case study. Advances were made in two methods used to examine intra-urban variability, namely passive air sampling and land use regression analysis. The study showed that these methods are useful for assessing local-scale variability, and that passive air sampler concentrations are most reliable when using homologue-specific sampling rates obtained from a co-located low volume sampler. The results of the spatially and temporally distributed sampling demonstrated that the highest atmospheric concentrations of SVOCs were associated with the highest density regions of the urban area. Temporal patterns of elevated concentrations of polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and polycyclic aromatic hydrocarbons (PAHs) in warm seasons were consistent with temperature-related emission processes such as volatilization and/or ventilation of indoor air. Spatial patterns in air concentrations were influenced by local sources on a scale of <5 km and were explained by factors related to human population activities such as building volume (PBDEs), population density (polycyclic musks, or PCMs), residential, commercial and transportation infrastructure (PAHs), and chemical inventory (PCBs). Industrial activities were not important factors. The link between elevated environmental concentrations and the in-use stock of banned chemicals, such as PCBs and PBDEs, suggest that efforts to control emissions and reduce environmental concentrations must address the removal of current use products, in addition to the bans on new uses of the SVOCs.