3. Electronic Theses and Dissertations (ETDs) - All submissions
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Item The baseline assessment of radiological levels of water in the West Rand Region, Gauteng(2022) Nkopo, Zandile OdessaGold mining is one of South Africa’s economic injectors. Given South Africa’s unique geology, acid mine drainage (AMD) formed by mining activities allows for the dissolution and leaching of radionuclides into groundwater and potentially other drinking water sources under the right conditions. The aim of this study was to establish the baseline radiological levels of drinking water in the West Rand region of the Gauteng Province, South Africa. 23 water samples were collected from 9 towns within the study area and a liquid scintillation counter and Liquid Water Isotopes Analyzer (LIWA) model 45-EP were used for the analysis of tritium and stable isotopes respectively. Moreover, alpha spectrometry was employed for radionuclide analysis. Gross-α and gross-β activity concentrations were measured to determine the composition of radionuclides and identify the dominant radionuclides. The lowest activity concentration results reported were 15.3 mBq/L, 0.218 mBq/L, 4.73 mBq/L for uranium isotopes (234U, 235U, 238U); 2.28 mBq/L, 4.73 mBq/L, 18 mBq/L, 2.71 mBq/L for thorium isotopes (227Th, 228Th, 230Th, 232Th); -9.8 mBq/L, -34 mBq/L, -6.4 mBq/L for radium isotopes ( 223Ra, 224Ra, 226Ra); 1.2 mBq/L 210Pb, -16 mBq/L and -1100 mBq/L gross-α and gross-β respectively.. The highest activity concentrations reported were 210 mBq/L, 2.85 mBq/L, 62.0 for uranium isotopes (234U, 235U, 238U); 50.5 mBq/L, 33 mBq/L, 86.4 mBq/L and 23.5 mBq/L for thorium isotopes (227Th, 228Th, 230Th, 232Th); 13 mBq/L, 25 mBq/L and 19.5 mBq/L for radium isotopes (223Ra, 224Ra, 226Ra); 135 mBq/L 210Pb; 341 mBq/L and 13500 mBq/L for gross-α and gross-β respectively. The effective dose calculated from activity concentrations of all samples was within the allowed range (1 mSv/L to 3 mSv/L) of the WHO, UNSCEAR and DWAF drinking water guidelines. The low activity concentrations measured from the radionuclides suggest that the consumption of groundwater within the study area poses very little threat to human health but may cause severe health effects if it accumulates in the human body. The environmental isotopes results showed multiple moisture sources from global circulation, depleted δ 18O and δ 2H (-6.9‰ and -32.2‰, respectively) indicating that the recharging water underwent evaporation prior to recharge. Tritium was used to estimate the groundwater residence times and its activity concentration ranged from 9.44 to 28.32 mBq/L. Low 3H activity concentrations are indicative of new to relatively young waters.Item Facing the challenge of learning and teaching gold mining grade 11 in the new curriculum : a self-study.(2012-08-31) Ndhlovu, MajabulileThe South African government that was elected in 1994 made tremendous changes in the Education system. The new government came up with the new curriculum for Basic Education (grade R- 12). The new curriculum had new topics in physical science. This made me as a teacher doubt whether I would be able to teach new topics. During my time as a student, I was not taught mining at school or college. As a result, I decided to do a self study in order to investigate how I would learn gold mining as a topic in order for me to be able to teach it to my learners. My study involved studying my own teaching practice while learning and also finding out the key things that made me understand the content knowledge involved in the topic of gold mining. The self study was done in order to ensure that I understood the content knowledge and how best to teach it to the learners. I used a collaboration team, reflective journal, group interviews classroom observation and learners’ responses to collect data. The participants were my grade 11 learners and myself. My data was analysed using a PCK model, CoRes and PaPeRs. I had to learn the content knowledge and transform it to make it understandable to learners. I designed lessons using the prior knowledge of learners and integrating Physical Science and Geography. Lessons did not go as smoothly as I had expected. Learners wanted some of their existing knowledge to be included. The classroom activities depended entirely on the relationship between the teacher and learners. I carried out my study bearing in mind that implementation of the new curriculum depends not only on classroom interactions (DoE, 2002) but most importantly on the content knowledge that the teacher has and how it is transformed. Learners taught me to understand gold mining from the geographical point of view as well from the scientific point of view. From the beginning of the study they were really excited and were looking forward to new things. Using the learners’ science prior knowledge helped me design lessons that allowed me to learn to be a facilitator.