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Thesis (MSc (Environmental Sciences))--North-West University, Potchefstroom Campus, 2012. One of the major constrains in beekeeping is damage caused by the greater wax moth (Galleria mellonella). Due to problems and concerns regarding the use of chemical insecticides, biopesticides have been introduced to manage problematic insects. For the biological control of greater wax moth, Bacillus thuringiensis subsp. aizawai (B.t.a) has been widely researched and used. Large scale production of B.t.a as a biopesticide is expensive because of the high cost of commercial media formulations. In this study, three raw materials, horse manure, soy meal and maize chops, were selected for evaluation as raw materials for media production based on their economical feasibility and availability and compared to two commercial media (Tryptone soy broth and bactopeptone). Sixty three raw material formulations and two commercial media were evaluated in terms of spore yield and toxicity towards G. mellonella. For each formulation the spore and vegetative cell yield was determined using direct microscopy. From the results obtained from the 63 formulations, the 12 highest spore yielding formulations were selected and re–evaluated for confirmation of the results. Spores obtained from the 12 highest spore yielding formulations were used in a bioassay to determine their toxicity against G. mellonella larvae and the protein concentration were also determined. Spore morphology was investigated for the 12 highest spore yielding formulations. Formulations containing 3.75 g horse manure, 5 g maize chops and with soy meal ranging between 1.25 g and 3.75 g yielded the highest spore yields. In particular the combination of 3.75 g horse manure, 5 g maize chops and 1.25 g soy meal had the highest spore yields but also resulted in 100 % mortality against G. mellonella larvae within 3 days. The yields obtained were also significantly higher than those for the commercial media against which they were evaluated. As such it was concluded that the selected formulation represents a feasible alternative to commercial media for the production of B.t.a. Masters

Thesis (M. Environmental Science)--North-West University, Potchefstroom Campus, 2009. South Africa is one of the most important mining countries in the world, hosting the world's largest reserves of platinum group metals (PGMs). Even though mining is clearly an important activity in South Africa, contributing approximately US$ 7.4 billion annually to the countries' gross domestic product (GDP), the costs to the environment are not insignificant. One of the most severe environmental aspects associated with mining is the storage of mineral waste on tailings storage facilities due to their impacts on air quality, ground water quality, aesthetics and land use. It is also unknown whether the environmental effects of tailings storage facilities increase or decrease over time. The aim of this study was to determine the ecotoxicity of platinum tailings storage facilities of different ages by means of soil physical and chemical analysis, earthworm ecotoxicological studies, dehydrogenase activity and soil mesofauna studies. Samples were obtained from three platinum tailings storage facilities of different ages of which two were already rehabilitated while the third was still operational at the time this study was performed. The latter was used as a negative control for the purpose of the study. Soil samples were physically and chemically analysed. Earthworm ecotoxicological studies were conducted to determine changes in biomass, reproduction, mortality, neutral red retention times and tissue metal concentrations. Dehydrogenase activity was determined before the introduction of earthworms and manure, after introductions of manure and after introductions of earthworms and manure. Soil mesofauna were extracted and identified in order to determine species richness, diversity, abundance and functional grouping. Soil chemical analysis indicated that concentrations of certain heavy metals, especially chrome (Cr), present in platinum tailings materials could have a potential effect on microorganisms, microbial processes and earthworms. Earthworm ecotoxicological results indicated that earthworms that bioaccumulated higher levels of heavy metals showed poor hatchability of cocoons. Dehydrogenase activity indicated that earthworms play a significant role in increasing the number and biomass of soil microbes because significant increases in dehydrogenase activity were noticed after the addition of earthworms to platinum tailings materials. Results from the earthworm ecotoxicological studies, dehydrogenase activity, and soil mesofauna composition indicated that environmental impacts of tailings storage facilities did not increase with age, but is more likely to be an indication of the rehabilitation measures administered to the different tailings storage facilities. Masters

Thesis (M. Environmental Science)--North-West University, Potchefstroom Campus, 2006. The disposal of solid waste material produced by mining activities can have vastly negative environmental impacts with regards to soil ecosystems. Global and South African legislation requires the mining company to rehabilitate the disturbed area in such a manner that sustainable ecosystem stability is achieved. Rehabilitation of co-disposed diamond tailings at Finsch mine (De Beers) entails the application of organic matter in the form of vermi-compost, organic and inorganic fertilizers, as well as different grass seed mixtures. Optimal amounts of chemical ameliorants were determined in a previous experimental trial prior to the current field study at the mine. The aim of this study was to evaluate the rehabilitation progress by analysis of soil microbial communities as biological indicators of sustainability. Soil quality can be determined by the analysis of physical, chemical and biological soil properties. Chemical analysis of the tailings material was done by 1 :2 water extract, as well as ammonium acetate extraction techniques. Enzymatic analysis (dehydrogenase, acid and alkaline phosphatase, f3-glucosidase and urease) as well as substrate induced respiration (SIR) was used to determine the soil microbial community function. Soil microbial community structure was evaluated by the analysis of specific microbial lipid biomarkers. The vegetation response towards the rehabilitation effort was evaluated by determination of subjective ratings for plant species frequency and density, and plant biomass. Plant vitality was determined by analysis of photosynthetic activity, which is known to be extremely sensitive towards environmental disturbance. In terms of overall enzymatic activity (dehydrogenase), the application of 90-tonlha vermi-compost in the experimental plots showed the best results. No statistically significant differences in SIR results were noted in the experimental plots. However, the plots treated with 60-tonslha vermi-compost showed the best results in terms of plant vitality and plant biomass. The determination of soil microbial community structure showed that fungal to bacterial ratios were increasing over time although actual ratio values are much less than one, and that overall bacterial population dominance is evident in the experimental plots. Masters

Thesis (M. Environmental Science)--North-West University, Potchefstroom Campus, 2006. Platinum mining activities contribute substantially to South Africa's economy since it exceeded gold as economical contributor in 2001. Mining activities contribute to large amounts of waste production in the form of tailings and rock waste, deposited in the surrounding environment of the mine premises. Mining companies are held responsible for damages caused to the surrounding environment. These companies are required to introduce the cost of ecological rehabilitation in their operation costs as well as compile an environmental management plan. Numerous attempts to rehabilitate mine waste have proven unsuccessful. New and improved rehabilitation techniques are required to facilitate in the rehabilitation of these mine spoils. Woodchip-vermicompost produced from platinum mining wastes (woodchips and sewage sludge) was used as an alternative amendment to inorganic fertilisers during the rehabilitation of platinum mine tailings. The effectiveness of the woodchip-vermicompost as an alternative amendment during the platinum mine tailings rehabilitation were monitored using different ecosystem components. A natural veldt in the vicinity of the mine area was randomly selected to serve as a reference site. These ecosystem components selected have previously been shown to be effective as indicators of ecosystem quality. The components selected for this study includes the use of microbial enzymatic activity, microbial community structure, nematode trophic structures, and other mesofaunal groups such as micro-arthropods. The physical and chemical properties of the platinum mine tailings and reference area as well as the vegetation cover of the platinum mine tailings were determined. Statistical and multivariate analyses were use to determine the correlation between the dependent microbial components and dominate independent chemical properties. Nematode trophic structure, Maturity Index, and Plant-Parasitic nematode Index were used to compare the two rehabilitation techniques in terms of nematodes as indicators. Microarthropods family structures were used to compare the two amendments in terms of diversity and abundance. Enzymatic activity was positively affected by the addition of woodchip-vermicompost, than in the sites treated with inorganic fertilisers. The microbial community structure showed no statistically significant (p < 0.05) differences between the two amendments. A higher abundance of nematodes especially plant-parasitic nematodes and bacterivorous nematodes were observed in the woodchip-vermicompost sites than in the inorganic fertilised sites. According to the Maturity Index, both amendments became more enriched during the study period, while the Plant-Parasitic nematode Index showed that the carrying capacity for plantparasitic nematodes on the woodchip-vermicompost sites increased while it decreased in the inorganic fertilised sites, which can be related to the decrease in vegetation cover on the inorganic fertilised sites. Both coloniser (Prostigmata) and persister (Cryptostigmata and Mesostigmata) groups of the micro-arthropods, as well as a higher diversity of micro-arthropods, were present on the woodchip-vermicompost sites whereas the inorganic fertilised sites showed only the presence of colonisers, with a decrease in diversity and abundance of micro-arthropods over the study. The colonisation of micro-arthropods may have been affected by the addition of woodchip-vermicompost and vegetation cover, which contribute to the establishment of suitable microhabitats for these soil biota. By intercorrelating the results, it may be concluded that the addition of woodchip-vermicompost may be an essential part of the rehabilitation process, by contributing to soil organic material to the ecosystem system, which may improve the recolonisation of soil biota and ecosystem processes. However further studies need to be conducted in order to determine the long-term sustainability of the woodchip-vermicompost in providing organic material and sustaining the ecosystem processes. The study also showed the necessity to integrate various ecosystem components when evaluating ecosystem development due to the unique role each component plays and the impact it may have on other components. Masters

Thesis (M. Environmental Science)--North-West University, Potchefstroom Campus, 2005 Increased amounts of pesticide production and application of pesticides for agriculture, plant protection and animal health has resulted in soil, water and air pollution, consequently relating a serious risk to the environment and also to human health. Pesticides include several groups of compounds, herbicides, insecticides, rodenticides and fumigants consisting of several hundred individual chemicals. Herbicides are an integral pan of modem agriculture and for industries requiring total vegetation control. Most herbicides are soil applied and more and more concern is raised that herbicides not only affect target organisms but also the microbial community present in soil. The ESKOM sub-station Zeus, in Mpumalanga (South Africa) used to apply an industrial weed control program for the eradication of vegetation, which led to the contamination of soil by several herbicides. These herbicides consisted of Bromacil, Tebuthiuron and Ethidimuron which are all photosynthesis inhibitors, more specifically, they disrupt the plastoquinone protein during electron transport at photosystem ll (PSII). In this study the effect of biostimulation and bio-augmentation of a specific bioremediation agent (B350) as prescribed by ESKOM, on residual herbicides, Bromacil, Tebuthiuron and Ethidimuron was evaluated by monitoring the soil physical and chemical properties, microbial attributes, including potential microbial activity and community structure, as well as the physiological effect experienced by plants (Cynodoh dactylon and Zea mays). Results from soil physical and chemical analyses were correlated with results obtained for the functional and structural diversity of microbial communities. All results were investigated through statistical and multivariate analysis and the most prominent soil physical and chemical parameters that influence the biological and biochemical properties of the soil were identified. Results obtained from this study indicated that there were no significant difference (p < 0.05) between the treatments, with bioremediation agent, irradiated agent and without the agent based on results obtained from soil microbial properties and plant physiology. Before the trial started the uncontaminated soil showed an active microbial function, characterised by dehydrogenase, urease and arylsulphatase activity, but community structure was not very diverse. The contaminated soil, irradiated contaminated soil and silica sand showed less enzymatic function and was characterised by phospholipid fatty acid groups, mid-branched saturated fatty acids, terminally branched saturated fatty acids, normal saturated fatty acids and monosaturated fatty acids which are indicative of microorganisms that survive better in harsh environments. Three weeks after the addition of the specific bioremediation took place, the uncontaminated soil showed an increase in P-glucosidase activity and percentage organic carbon (%C), which could be a result of the presence of available plant material. Furthermore, an increase in major PLFA groups were seen, suggesting that an increase in diversity within the soil community occurred. The contaminated soil, irradiated contaminated soil and silica sand once again was characterised by a low microbial function and diversity, showing no improvement. Fluorescence data clearly show a decline in PS ll function that result in the decline of the rate of photosynthesis, which was seen from COz gas exchange rates. Furthermore, the decrease in photosynthetic activity after three weeks was too severe to supply additional information about the mechanism within photosynthesis or the photoprotective mechanisms. A detailed study was conducted in which a 3: 1 dilution of contaminated soil with silica sand, was also monitored for changes within plant physiology. Results revealed that inhibition of PS ll function already takes place within a few days time and the decline in photosynthesis is as a result of electron transport that does not supply adenosine triphosphate (ATP) and P-nicotinamide adenine dinucleotide (NADPH) to the Calvin cycle (or Reductive Pentose Phosphate pathway). It does not appear that rubulose-1,5-bisphosphate carboxylase-oxygenase (Rubisco) is affected within the Calvin cycle. As a result of PS II function failure, reaction centres are damaged by the production of harmful singlet oxygen and photoprotective mechanisms (xanthophyll cycle) can not be activated. Thus, except for dealing with ineffective electron transport, additional damage is caused to physiological functions. After six weeks a decrease in the estimated viable biomass for all growth mediums was found. Results of the of trans- to cis- monoenoic fatty acids and cyclopropyl fatty acids to their monoenoic precursors ratios indicated that the soil microbial community for the contaminated growth mediums, all experienced nutritional stress throughout this trail. The specific bioremediation agent (B350) used, seemed to have no effect on the microbial function and community structure within soil and as agent had no effect on the residual herbicides or the plant physiology which experienced an extreme decline in major metabolic functions. Masters