Although a vast number of air quality investigations have been conducted on the Mpumalanga Highveld previously, there has been limited attempt to integrate available datasets from the different methods of air quality monitoring (satellite, insitu and ground-based observations) and modelling. This study compares modelled, satellite and measured data to determine the most accurate estimate of ground level sulphur dioxide (SO2) and nitrogen oxide (NOx) concentrations. The main value of the project comes from the ‘improvement’ of modelled concentration fields using measurements. Measurements only provide information on air quality at isolated places (for example monitoring stations) or at isolated times (aircraft measurements and satellite observations). Dispersion models predict concentrations continually over a wide area. However, models have inherent inaccuracies based on the assumptions made in developing the model and the variability in the input parameters supplied. These can be accounted for or are part of the inherent variability of the model results. This study assists in the refinement of modelled outputs as well as the verification of satellite data using ground-based measured data as a point of reference. In the wake of increasing governance on air pollution, industry has been compelled to account for their impacts on the environment. This study aids industry by proposing a method to quantify their impacts on the environment and possibly on human health. Three datasets from 2003 (modelled, measured and satellite) were integrated using a geographic information system in order to analyse and interrogate the data and produce an integrated set of data, maps of potentially sensitive ecosystems and maps of potential exposure to poor air quality of sensitive population groupings. The results of the study have shown that although the concentration value for the NO2 iv tropospheric column is greater than the values observed on the ground there is a good correlation between measured observations and SCIAMACHY retrievals. The sample size was too small to indicate a statistically significant bias. The results from the validation of the CALPUFF model indicate with respect to SO2 predictions that themodel is only reliable for 62% of the time within the United States Environmental Protection Agency’s model performance guideline of acceptance i.e. predictions within a factor of 2, and for NO2 the predictions are reliable for only 50% of the time. There is also no constant value by which the model under or over predicts. The cumulative distribution function graphs illustrate that the CALPUFF model predicts the highest values from the bulk of the distribution rather that the tail of the distribution where the extremes lie. This could possibly account for the large variance between measured and modelled outputs. The results of identifying areas of potential harm from SO2 emissions reveal that hotspots for high to very high risk to human health occur around all power stations. Generally the category of high risk around power stations seems to be located in areas with population agglomerations between 0-1 000 per km2 and 2001- 5000 per km2. Several high risk areas for potential harm to ecosystems from SO2 emissions can be seen on the Highveld with a large spatial extent around Kendal, Matla and Kriel power station. Approximately 871 wetlands fall within the high risk areas. The vegetation risk map indicates a high risk to several grassland and bushveld types. Model results for this study indicate no potential risk to human health from emissions of NO and subsequent conversion to NO2 in the atmosphere.

Lephalale Municipality is a predominantly rural Municipality with 38 villages, two townships (Marapong and Onverwacht) and one town, Lephalale. Lephalale, formerly known as Ellisras, is a town situated in the “heart of the Bushveld” in Limpopo province. The town is growing rapidly and more industries are becoming concentrated within this small town. The construction of Medupi power station which is underway and other projects such as the expansion of Grootegeluk mine (coal 3 and 4 projects), and road developments in the area; have led to concern about the ambient air quality of the area. Other possible future projects are the Coal to Liquid project by Sasol and the Coal Bed Methane project by Anglo American Thermal Coal. The purpose of this study is to determine the ambient air quality impact of the Matimba power station in the Lephalale area. The AERMOD model and ambient air quality data obtained from Eskom’s Grootstryd and Marapong monitoring stations were used to assess the ambient air quality of Lephalale. Sulphur dioxide and Nitrogen oxides were investigated. Both the model’s results and the ambient air quality monitoring data indicated that the power station contributes to high -ground level concentrations of Sulphur dioxide. AERMOD simulated the nitrogen oxides results as nitrogen dioxide. From the study it is concluded that the power station is not the only source of nitrogen oxides. Nitrogen oxides concentrations were associated with low-level sources. The relationship between the criteria pollutants in this study was assessed. The study found that there is no relationship between sulphur dioxide and nitrogen oxides. This finding was used to support the idea that sulphur dioxide and nitrogen oxides are from different sources. It was also established that seasonality has an influence on the ground level concentrations of pollutants in the area.

Thesis (M.Sc. (Aquaculture)) -- University of Limpopo, 2020 / The aim of the study was to assess the extent to which biological indicators and biomarkers can be used to monitor the pollution status of the Sand and Blood Rivers. Physico-chemical parameters were assessed as a primary approach in assessing pollution status of the Sand and Blood Rivers. Temperature, pH, dissolved oxygen (DO), biological oxygen demand (BOD), turbidity, total dissolved solids (TDS), total nitrogen, phosphorus and ammonia were assessed during the rainy and dry seasons. Physico-chemical parameters showed spatial and temporal variation. The hierarchical average linkage cluster analysis grouped the reference sites (S1 and B1) into one group and sites after points of discharge (B2, S2, S3, S4 and S5) into another group. This grouping was due to the pollution status of each site, with the reference sites less polluted than the sites downstream of the wastewater treatment plant effluent points of discharge. The canadian council of ministers of the environment water quality index (CCME WQI) categorized reference sites as good, whilst sites after points of discharge were categorized as poor. This shows that the Sand and Blood Rivers are degrading. Heavy metal contamination in water, sediment and grass from the Sand and Blood Rivers was evaluated during the rainy season and dry season. All assessed heavy metals (Cadmium, Chromium, Copper, Iron, Lead, Manganese, Nickel, and Zinc) were below the detection limit in water, with an exception for Iron and Manganese. All metals assessed were also below the probable effect levels (PEL) according to the CCME. Geo-accumulation Index showed that the Sand and Blood Rivers were not contaminated with heavy metals. The enrichment factor (EF) further showed that only site B2 was enriched with manganese from anthropogenic activities. Heavy metal assessment in Cyperus exaltatus showed that this grass is a poor candidate for phytoremediation. Macroinvertebrates were used as biological indicators to assess pollution status of the Sand and Blood Rivers. Macroinvertebrates were sampled according to South African scoring system (SASS) and identified using aquatic invertebrates of South African rivers field guide. The SASS and average score per taxon (ASPT) categorized all sampling sites as critically modified. The family-level biotic index (FBI) also showed that the Sand and vi Blood Rivers are enriched with organic pollution. The reference sites recorded high macroinvertebrates diversity, compared to the sites after points of discharge. All indices used showed spatial and temporal variation in the water quality of the Sand and Blood Rivers. The relationship between macroinvertebrates and physico-chemical parameters were explored with the use of canonical correspondence analysis (CCA). The CCA triplots showed that the reference sites were associated with pollution sensitive taxa, whilst pollution tolerant taxa were associated with sites after points of discharge. Moreover, sites after points of discharge strongly correlated with phosphorus, nitrogen, ammonia, BOD and TDS. Clarias gariepinus gills and liver histology were used as biomarkers in assessing pollution status in the Sand and Blood Rivers. Gills and liver samples were qualitatively and semi-quantitatively assessed. Fish from the reference sites had less gill lesions than fish from sites downstream. Alterations such as hyperplasia of interlamellar, fusion of secondary lamellae, epithelial lifting and hyperplasia of secondary lamellae were observed in fish collected from downstream. Fish from downstream also showed more liver alterations than fish from the reference sites. Alterations such as melano-macrophage centers (MMC), macrovesicular steatosis, sinusoid congested with kupffer cells, nuclei pleomorphism and vacuolation were identified in liver of fish from sites S4 and S5. This was further confirmed by the high gill and liver indices of fish from downstream. Acetylcholinesterase enzyme (AChE) enzyme in brain and lactate dehydrogenase (LDH) in liver of Clarias gariepinus were used as biomarkers in assessing pollution status of the Sand and Blood Rivers. Both AChE and LDH enzymes were lower on fish from downstream compared to fish from the reference sites. This shows that AChE and LDH enzymes on fish from downstream were inhibited. This was attributed to the use of pesticides on farms surrounding the Sand and Blood Rivers and also the discharge of poorly treated sewage effluent from the Polokwane and Seshego wastewater treatment plants (WWTP’s). The Sand and Blood Rivers are surrounded by farms that utilize pesticides in their practice. This study showed that biological indicators and biomarkers can be used to assess pollution status of the Sand and Blood Rivers. However, biological vii indicators and biomarkers should be used in concurrence with physico-chemical parameters. / Department of Agriculture Forestry and Fisheries, Water Research Commission (WRC) and Aquaculture Research Unit.

Thesis (M.Sc. (Zoology) -- University of Limpopo, 2019 / The Olifants River is one of the major river systems in South Africa, providing water for industries, mines, agricultural and domestic activities. Consequently, the river has turned out to be one of the most polluted rivers in South Africa. The Blyde River is an important tributary of the Olifants River, known for its continuous flow and good water quality. However, the recent increase in human activities such as, commercial agricultural and large-scale forestry practices in the catchment may have a negative impact on the quality of the water, which may consequently affect the aquatic biota community structure. The aim of the study was to assess the water and sediment quality of the Blyde River using aquatic macroinvertebrates as bioindicators and the South African Scoring System version 5 (SASS5) protocol was followed. Seven sampling sites were selected at Blyde River and five samples were collected per site. Collected macroinvertebrates were identified to family level and classified according to their tolerance levels to pollution at the University of Limpopo Biodiversity Laboratory. In addition, seasonal readings of the physico-chemical parameters such as, pH, dissolved oxygen (DO), temperature, salinity, total dissolved solutes (TDS) and electrical conductivity (EC) were recorded in situ using YSI Model 554 Datalogger with a 4 m multiprobe and a Mettler Toledo SevenGo™. Most of the physico-chemical parameters recorded at Blyde River were within the South African water quality guidelines for aquatic ecosystems. Metals such as, As, Al, Ba, B, Cd, Cr, Co, Cu, Fe, Pb, Mn, Ni, Se, Ag, Sr, Sn, Ti, V, and Zn were tested from the water column, sediments and macroinvertebrate tissue. Almost all the metals analysed from the water column and sediments were within the quality guidelines. Out of the twenty tested metals, As, Ag, Cu, and Zn exceeded the recommended quality guidelines in the water column at some sites. Only As, Cr and Cu exceeded the recommended quality guidelines in the sediments. The most abundant macroinvertebrates were from the orders Ephemeroptera, Diptera, and Trichoptera at all sites. There was a similar macroinvertebrate community structure across the sites, supported by the positive correlation analysis among the sites (r > 0.4). Wildlife Estate and Wildrivers Estate had the highest and lowest numbers of sensitive macroinvertebrates respectively. The highest percentage of iv sensitive macroinvertebrate taxa was recorded in winter and the highest percentage of tolerant species was recorded in summer. This was also supported by the SASS indices, the SASS score, number of taxa and average score per taxon (ASPT) were highest in winter, followed by autumn, spring and lowest in summer. The overall SASS indices showed that the water quality condition at most of the sites at Blyde River could be considered as good. All the seven sites on average fell under ecological band A and B, except for the Wildrivers Estate, thus, the water quality status of the river could be described as unmodified and largely natural with few modifications. / VLIR

A dissertation submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science June 2015 / Lephalale is the home of Matimba, one of Eskom’s coal-fired power stations. Matimba is the biggest power station with a dry cooling system in the world. There are other industries (including coal mines) currently in operation in close proximity to the station. This industrial area is expected to grow as more industrial activities are planned for the following years. These activities will aggravate the levels of air pollution and possibly result in it being a “hot spot” for air pollution. The impact of air quality on health is covered by the National Ambient Air Quality Standards (NAAQS), but the impact of air quality on the terrestrial and aquatic ecosystem is not known. Therefore, this study focuses on the deposition of nitrogen oxides (NOx) (as nitrogen dioxide (NO2)) and sulphur dioxide (SO2) within Lephalale in the Waterberg-Bojanala Priority Area. Additionally, inter-annual variability of NOx and SO2 ambient concentrations and back trajectories of air masses were analysed. The study obtained ambient air quality data and meteorological data from Eskom for the period 2008–2012, while additional meteorological data were obtained from the Agricultural Research Council (ARC) and the South African Weather Service (SAWS). An inferential model was used to estimate the dry deposition flux of SO2 and NOx (as NO2), and the Hybrid Single Particle Langrangian Integrated Trajectory (Hysplit) Model was used to cluster back trajectories of air masses. The results of the seasonal dry deposition velocities of SO2 (0.17 to 0.23 cm/s) and NOx (0.10 to 0.15 cm/s) (as NO2) were higher in summer and lower in winter. They were also within the magnitude of the deposition velocities found in previous studies in the Highveld. The high deposition velocities in summer were attributed to photosynthetically active vegetation, turbulence and solar radiation. However, seasonal dry deposition fluxes of SO2 and NOx were higher in winter across the years. The higher flux values in winter were attributed to higher ambient concentrations of the trace gases. Additionally, the annual dry deposition flux of SO2 ranged between 0.43 and 0.67 kg S ha-1 yr-1, while NOx (as NO2) ranged between 0.84 and 1.05 kg N ha-1 yr-1 over the period studied. The annual deposition flux values found in the current study are lower than those found in previous studies in the Highveld. This difference could be because of the lower ambient concentrations of SO2 and NOx observed in this study. There is an inter-annual variability of the ambient concentrations of SO2 and NOx during the period 2008–2012. However, the difference is not large or statistically significant. The dominant direction of the back trajectories of air masses is east and southeast across all seasons for the entire period of 2008–2012. This lack of seasonal pattern in back trajectories and source regions cannot explain the seasonal changes in ambient concentrations (SO2 and NOx). Hence, climatic factors (e.g. change in weather) or seasonal changes in combustion source intensity must be responsible.

MPH / Department of Public Health

MESMEG / Department of Mining and Environmental Geology / The increase in the demand and market price of gold has led to reprocessing of gold tailings in many parts of the world. Mines are recently closing down due to depletion of resources and increasing mining costs leading to the reprocessing of old tailings dams. The cost of rehabilitation is high, and therefore a more convenient way of rehabilitation is required. The most convenient strategy identified here was to reprocess tailings for gold and use waste rocks as construction materials. The tailings residues (waste remaining after reprocessing) will be relocated to a more convenient place to avoid pollution. Gold reprocessing from tailings dams has gained momentum in South Africa especially in the Witwatersrand Basin where there are large volumes of tailings. Gold is being reprocessed from tailings in this area using hydraulic monitors. This study focused on the evaluation of gold and heavy metals within the tailings at Consolidated Murchison Mine tailings in Gravelotte, Limpopo province. Augering was conducted over the tailings up to a depth of 8 m along four sampling Profiles. The first profile had two sampling points, the second profile with three sampling points, the third and fourth profiles consisted of four and five sampling points respectively. Samples were collected at 1 m interval, therefore a total of 112 samples were collected and analysed for heavy metals using X-Ray Fluorescence spectrometry and 84 samples were analysed for gold using fire assaying. Tailings sampling was accompanied with tailings logging, taking note of colour, texture and moisture content. Based on this, the oxidation status of the tailings dam was determined. Oxidation zone of this tailings dam was mainly from top down to a depth of 3 m. The transitional zone was not identified, hence after the oxidation zone, the rest was unoxidized zone. This study established that gold was erratically distributed within the tailings dam with the lowest and highest values of 200 mg/kg and 1880 mg/kg respectively and the average was 670 mg/kg. The tonnage of tailings within the dam was found to be 13 280 310 tons with a total gold amount of 8 897. 81 kg. At the current world market, this interprets to US$ 306 932 396.00 (R 4 281 706 924.20). It was concluded that this tailings dam is economically viable for reprocessing, although previous studies have indicated that it is not possible to extract gold from tailings dams completely. The heavy metal content of Pb, Ni and Cr were found to be high with average values of (ppm); 5631.5, 2062.6 and 1345 v respectively. The metals with the lowest values were Cd, Co and Cu, averaging (ppm); 0.01 ppm, 19.8 ppm and 42.1 ppm respectively. Heavy metal content in soil around the tailings dam was gradually decreasing with distance from the tailings dam. Waste rocks have been used in some parts of the world as sub-base material for engineering construction, hence in this study, a total of 6 waste rock samples were collected using grab sampling method for geostatistical investigation. Such samples were subjected to various geotechnical tests which included particle size distribution analysis (sieve analysis), Atterberg limit tests and laboratory compaction test to determine their suitability for construction. The waste rock material was found to be suitable for road construction as it was classified under Group A-1-a using the AASHTO classification system. The material consisted mainly of rock fragments, gravel and sand material with minor silt/clay. In general, Consolidated Murchison mine waste was found to be suitable for road construction. / NRF

Department of Hydrology and Water Resources / PhDH

MPH / Department of Public Health / See the attached abstract below

MSc (Zoology) / Department of Zoology / Many chemicals released into the environment are believed to disrupt normal endocrine functions in humans and animals. These endocrine disrupting chemicals (EDCs) affect reproductive health and development. A major group of EDCs that could be responsible for reproductive effects are those that mimic natural oestrogens, known as xeno-oestrogens. A number of in vivo and in vitro screening strategies are being developed to identify and classify xeno-oestrogens, in order to determine whether they pose a health risk to humans and animals. It is also important to be able to apply the assays to environmental samples for monitoring purposes. Oestrogens and androgens mediate their activity via intracellular receptors – directly in muscular tissue as well as indirectly via stimulation of growth hormones from the pituitary glands and other growth factors from liver plus several other organs. Mancozeb is a metal ethylenebisdithiocarbamate (EBDC) fungicide used to protect many fruits and vegetables and field crops against pathogenic fungal. It causes a variety of defects on the female reproductive system in experimental animals and is therefore considered a suspected EDC. This fungicide can also induce toxic effects in cells of the immune system and other non-immune cells leading to genotoxicity and apoptosis. The mechanisms of EDCs involve divergent pathways including (but not limited to) oestrogenic, antiandrogenic, thyroid receptors; that are highly conserved in wildlife and humans, and which can be modelled in laboratory in vitro and in vivo models. The endocrine disrupting properties of Mancozeb are not known as of yet and therefore the T47D-KBluc reporter gene assay, GH3.TRE-Luc and MDA-kb2 reporter gene assay were used determine the possible endocrine disrupting activity/potential there-of. No activity was detected in any of the assays and no mancozeb was detected in any of the dams either. Oestrogenic activity was detected in Albasini Dam, Nandoni Dam and Xikundu weir but all values were below 0.7 ng/ℓ trigger value for oestrogenic activity in drinking water. / NRF