M.Sc. / This study concentrates, not only on the physical origin of the pans, but also attempts to define certain guidelines which will contribute to an improved urban environment in the future. The series of pans on the East Rand form part of the greater Highveld pans, which extends in an easterly direction to eventually link up with the Lake Chrissie pan series. The study is however limited to those pans appearing on the 1: 50 000 topographical map 2628 AB Benoni ...

M.A. / Pan are naturally occurring depressions or closed basins and play a very important role in ecosystems. The East Rand is characterized by more than one hundred pans dotting its landscape. The impact of urbanisation on these pans is significant. To determine exactly how the characteristics of the pans on the East Rand has changed, a comparison was done between the characteristics and utilization of the pans in 1992, as then described by Le Grange (1992) and the current situation in 2003. Water samples were also collected over a period of three months and analysed in the laboratories of Rand Water. The current utilization of the pans leaves much to be desired. Informal settlements, industries, residential areas and mine dumps are all found on the pan floors. Large waste dumping sites are developing at five out of the 19 pans in the study area. This has severely negatively affected the water quality within the pans, and the quality of bird life at thee pans. Continuous research is needed from government and private organisations on the pans found on the East Rand to improve their current quality and condition. Responsibility and proper management strategies must be implemented to protect the pans from negative human impacts.

Master of Science / Despite Chrissie Lake being South Africa’s largest freshwater lake, the chemistry of this lake and the surrounding lakes and pans in the Mpumalanga Lake District has never been studied in detail. These closed systems show varying chemistry while being in very close proximity to one another, adding to the uniqueness of this area where pans, usually typical of arid regions, are found in a humid area. The factors affecting the water chemistry of these lakes needed to be identified and explained. In order to evaluate the water chemistry in this unique environment, water samples were taken at the end of the wet and dry seasons, in April and September 2007 respectively. The major pans were sampled, as were adjacent fountains or springs, indicative of the perched groundwater aquifers found in this area, as well as borehole water from the surrounding farms. Alkalinity was determined by manual titration upon returning from the field while pH and conductivity measurements were performed on site. Major cations and anions were analysed for using ICP-OES and Ion Chromatography respectively. Sediment samples were collected from the floor of each pan in the summer sampling and the mineralogy determined by X-ray diffraction (XRD). During September 2007 sampling, precipitates found on the floors and banks of the pans were also collected and analysed using XRD, to identify mineral species precipitating from solution. Results from the above analyses show that each pan in the MLD has a unique chemistry, which cannot be inferred from neighbouring pans. The inorganic chemistry differs from pan to pan as a result of these separate, closed systems being at different stages of the evaporation process. Throughout the path from groundwater to the pan, waters are subject to mineral dissolution and precipitation, adsorption and biological mechanisms, which continually add or remove solutes from solution. Although seemingly simple, there are certainly other factors that play a role in the evolution of the water chemistry. Key to the current inorganic chemistry is the balance between import and export of solutes. The groundwater, predominantly the perched aquifer water, brings solutes into the pans and blowouts of precipitates on the pan floor at the end of the dry season, when the wind is strongest, results in the export of solutes. This process is significant in maintaining the overall freshness of the pans in the MLD, contrasting to their western counter parts that evolve to highly saline saltpans. Other factors such as the periodicity of pans drying completely, the surface area to catchment area ratio (CA/SA), the formation and dissolution of efflorescent crusts and the presence or absence of reeds all have varying effects on the water chemistry of the lakes and pans. Significantly, the amount of evaporative concentration that a pan evolves through has been shown to be dependant on the CA/SA ratio with pans having larger ratios being lower in salinity compared to those with low ratios being the most saline pans. The reservoir available to the pans with the large catchment areas sustains these pans through the dry months and slows the progression of evaporation. It is clear that the factors affecting the hydrochemistry of the pan waters can not be simplified to a single process affecting a single dilute inflow of water to produce our final solution of evaporated pan water. Instead, water in the pans reflects a long-term evolution of solute species, with some memory effect remaining after each season of evaporation. The result is an accumulation of solutes as they are added continuously via dilute inflow and then removed from the waters at various times, particularly during dry periods when evaporite minerals are formed and transported out of the system.

M.Sc. / Mpumalanga, “the place where the sun rises”, sets the scene for one of the rarest wetland types in South Africa. They are formed on one of the last remnants of the ancient African land surface, contain peat and together with a variety of other pan types make up the Mpumalanga Lakes District. Of these approximately 320 pans, only ±2.3% are reed pans. These endorheic wetlands are unique from other pan types and peatlands in South Africa and support an abundant biodiversity. They perform vital functions such as water storage, filtering out impurities and carbon fixation, which prevents an excess release of CO2 into the atmosphere. There is very little known about these endorheic wetlands and thus they are constantly being threatened by various activities such as agriculture, livestock and mining. The objectives of this study were to determine the spatial and temporal variation of macroinvertebrate community structures of reed pans and the environmental factors, such as water quality, responsible for the maintenance of these structures; to determine the best method for sampling aquatic invertebrates in reed pans; as well as to determine the relationship between aquatic invertebrates and the water, sediment and habitat quality of a reed pan. Together with this the amphibian diversity as well as the occurrence of other biotic components was determined. Four reed pans were assessed during four different seasons over a one year period to account for the different hydrological extremes. Sub-surface water samples were analyzed for their suspended solid content, nutrient levels, metals and chlorophyll-a concentrations as well as in situ water quality parameters. Sediment samples were analyzed for metal concentrations, organic carbon and water content, as well as sediment size distribution. Invertebrates were collected using the following sampling techniques: aquatic light trap, terrestrial light trap, emergent trap, sweep net, plankton net, as well as benthic sampling using an Eckman grab.

M.Sc. (Geology) / Despite Chrissie Lake being South Africa's largest freshwater lake, the chemistry of this lake and the surrounding lakes and pans in the Mpumalanga Lake District has never been studied in detail. These closed systems show varying chemistry while being in very close proximity to one another, adding to the uniqueness of this area where pans, usually typical of arid regions, are found in a humid area. The factors affecting the water chemistry of these lakes needed to be identified and explained. In order to evaluate the water chemistry in this unique environment, water samples were taken at the end ofthe wet and dry seasons, in April and September 2007 respectively. The major pans were sampled, as were adjacent fountains or springs, indicative of the perched groundwater aquifers found in this area, as well as borehole water from the surrounding farms. Alkalinity was determined by manual titration upon returning from the field while pH and conductivity measurements were performed on site. Major cations and anions were analysed for using ICP-OES and Ion Chromatography respectively. Sediment samples were collected from the floor of each pan in the summer sampling and the mineralogy determined by X-ray diffraction (XRD). During September 2007 sampling, precipitates found on the floors and banks of the pans were also collected and analysed using XRD, to identify mineral species precipitating from solution. Initial results show pH values ranging from 7.0-10.5 for the lakes and pans and from 6.0-8.0 for the borehole water and springs. Values as low as 100 mglL Total Dissolved Solids (TDS) were measured for the pans, with maximum values set at 10 giL for the most saline of these bodies of water in the wet season and as much as 90glL for a pan almost completely dried out in the dry season. The water in the closed pan systems are dominated by Na-CI- HCO~ and have varying concentrations of major cations. The dilute spring waters have TDS values ranging from 20-200 mg/L, indicating the excellent quality of the groundwater, while some boreholes reach values of I 000 mg/L TDS showing possible linkage to pans or leaking of the pan water into the surrounding strata. To understand the main processes affecting the inorganic chemistry of the surface and shallow groundwater of this area, major ions were plotted against chloride. The latter behaves conservatively and can thus be used to monitor the behaviour of solutes in the pan waters. These plots illustrate that the dominant process in the evolution of the waters in the MLD is evaporative concentration. Removal of species through mineral precipitation is clearly seen; carbonate species...

M.Sc. (Environmental Management) / Wetlands play a significant role in our environment as they provide a variety of goods, services and benefits to living species ranging from humans, animals and plants to microorganisms. Despite their importance, wetlands have somewhat been neglected over the past few years which has led to a rapid deterioration of wetland conditions and functions. Wetlands provide unique functions that cannot be provided by any other ecosystem; their value was recognised in the 1960s. Prior to this realisation the value of wetlands had been seriously underestimated to the extent where they were even previously labelled as “wastelands”. The reality is that to date minimal measures have been put in place to assist in the rehabilitation and future conservation of wetlands. The lack of wetland management and monitoring can be attributed to the fact that very little is known about the functioning of some of the wetland systems. Endorheic wetlands have recently been emerging as ecosystems of importance. Very little is known about endorheic wetlands and their ecological functioning. To date a fair amount of studies have been conducted on the pans in Mpumalanga and in the Free State but minimal information exists on the pans in the North West Province. The objectives of this study were therefore to compare the abiotic and biotic composition of pans in Mpumalanga and North West Provinces, in order to contribute to the knowledge which will eventually assist in devising rehabilitation measures and future conservation of pans in the area. Three different water ecosystem components were studied; these included aquatic invertebrate communities, water quality and sediment characteristics. The collected water samples were taken to an accredited laboratory to be analysed. When compared between the two provinces, the water-quality results indicated differences between provinces as well as among individual pans. However, most of the pans in both provinces show characteristics of being dystrophic alkaline systems. The invertebrates were collected using sweep nets and stored in jars containing 5% neutrally buffered formalin and a staining agent (Rose Bengal). The sediment characteristics were determined by using standard techniques and results showed that there were no obvious similarities between the different pans in the different provinces. Water-quality analyses were performed on samples taken during both winter- and summer-sampling surveys and these samples were analysed by a reputable laboratory. Based on the analyses of the invertebrate community samples, 25 taxa were identified; results show similarities in the structure of communities in both provinces with the exception of one or two different species. Sampling was conducted over a period of two seasons at all sampling points and several species were found belonging to different families. Invertebrates sampled in Mpumalanga pans were similar to those reported in previous studies done in the area and most of the invertebrates sampled in Mpumalanga and the North West are known to be commonly found in temporary habitats. Spatial and temporal variations in invertebrate assemblages were determined; this analysis displayed differences in the different variables (biotic, physical and chemical) tested over the two seasons. The pans in Mpumalanga were dominated by coarse sand. Large amounts of coarse sand accompanied by poor water quality were observed in MP Pan A in Mpumalanga Province; this could be an indication of somewhat poor catchment management. The results of the abiotic and biotic comparison show that there are minor similarities and differences among the selected pans studied in each province. The knowledge acquired can now be utilised to enhance the available literature on these pans. Long-term studies have to be done to better understand the ecological functioning of the pans in the North West Province in order to devise mitigation measures as well as appropriate rehabilitation strategies and conservation measures.

M.Sc. (Aquatic Health) / Wetlands play an extremely important role in the hydrological cycle as well as biodiversity. Until recently, however, wetlands in South Africa have been neglected both in terms of research and monitoring. The lack of knowledge is even greater for the inward draining wetlands, which is better known as pans. Pans are isolated aquatic systems, which are quite shallow and do not have an outlet. Pans receive water from precipitation and surface runoff, and lose water mainly through evaporation. Some pans can be ephemeral (dry up often) and other perennial (dry up only during drought). The little ecological knowledge available is mainly focused on these ephemeral pans. In this present study conducted in the Western Free-State province, study was only focused on the perennial pans in this area. Due to the fact that this province are one of the biggest areas for gold mining in the country, the pans suffer under the impacts, and this results in the alteration of community structures in and around the pan, simplifying food chains which can lead to the collapse of an ecosystem. The aim of the study was to assess the water quality, bioaccumulation of toxicants (metals and pesticides) in sediment and aquatic invertebrate community of perennial pans in the Western Free State Province, mainly because of the lack of literature on pans in these areas. Seventeen pans were selected for the study of which eight were classified as saline eutrophic and nine as alkaline dystrophic. Various physico-chemical and sediment characteristics were assessed in addition to the characterization of the aquatic invertebrate communities. It became clear that there is great difference in the physical-chemical characteristics of the selected pans. The difference in the trophic state was the most clear, with differences in water colour, nutrient concentration and vegetation growth, classifying pans as either saline eutrophic or alkaline dystrophic. These trophic states influence the distribution and richness of aquatic invertebrates in certain pans. Mining activity, urbanization, agricultural activities and sewage runoff into the pan, all affects the pans negatively, there is sighs of water quality degradation as well as changes in the community structure of invertebrates when compared to the reference pans.