The research has entailed the formulation and coding of computer models for the design of pressurized irrigation systems. Particular emphasis has been given to the provision of routines for the evaluation of the expected performance from a designed system. Two separate sets of models have been developed, one for the block or in-field system and one for file mainline netWork. The thesis is presented in three seelions asfollows : * Basic theory, in which the general background to the research is covered. * The models, which includes detailed descriptions of both the design models and the computer programs. * Applications, in which several test casesof both sets of models are reported.

Chlorine dioxide has been used in drinking water treatment for the reduction of trihalomethanes and tastes-and-odors. Recently, chlorine dioxide was implicated as the source of offensive "cat-urine-like" and "kerosene-like" odors in drinking water. The purpose of this project was to determine the cause of odors observed in customers homes at times when chlorine dioxide was being applied to drinking water. Data were obtained through a survey and field sampling at utilities experiencing odor events. Once the cause was determined, potential water-treatment procedures were evaluated in laboratory-scale studies. Results from a survey sent to water utilities throughout the United States showed that customers who recently had installed new carpeting complained of odors more than those who had not. The use of chlorine dioxide caused responses to intensity of certain tastes-and-odors to increase, two of these odors were cat urine and kerosene. Field sampling at two water companies during odor events resulted in the discovery of low-levels of residual chlorine dioxide (0.2-0.7 mg/L) at the tap's of customers. Both the cat-urine- and kerosene-like odors were detected by the research team. To verify a proposed mechanism of odor generation, chlorine dioxide was volatilized in a room with new carpeting. Both odors were produced in amounts great enough to be easily detected by the entire panel. The removal of residual chlorite from drinking water would block a mechanism by which chlorine dioxide may be reformed from reactions between residual chlorite and free chlorine added for distribution system residual maintenance. Chlorite was removed by powdered activated carbon (PAC) enmeshed in alum floc in laboratory-constituted water and Po River water. A high level of PAC (50 mg/L) was required to effect good removal. A simulated floc-blanket clarifier effectively removed high levels of chlorite (>5 mg/L) from drinking water for long periods (12 hours) when PAC in high concentration was enmeshed in the floc. Chlorine dioxide reformed in the distribution system of two water companies. When customers opened water faucets, chlorine dioxide volatilized into the room and reacted with organic compounds present in the household air (e.g. from new carpeting) producing the offensive cat-urine-like and kerosene-like odors. The reformation of chlorine dioxide could be effectively eliminated if residual chlorite could be removed by contact with high levels of PAC enmeshed in an alum floc such as one could produce in a floc-blanket clarifier. / Master of Science

Emerging contaminants (EC) are unregulated substances that have entered the environment for as long as they have been produced through human activities. Within the ECs family, pharmaceuticals and personal-care products (PPCPs) is a class of the most common pollutants employed in everyday urban activities. Current regulatory approaches are inadequate to address these contaminants and the presence of such chemicals in the aquatic environment and their potential deleterious effects has received an increasing attention from the public and scientific community. Influent and effluent wastewater from Daspoort Waste Water Treatment Works (WWTW), which treats wastewater from the central Pretoria area, were sampled and analysed from January to December 2015 for pharmaceuticals and personal care products by gas chromatography time of flight mass spectrometry (GC/TOF-MS). Thirteen pharmaceuticals were selected for focused study in wastewater which include; (acetaminophen, bisphenol A, carbamazepine, diclofenac, 17α-estradiol, 17β-estradiol, estriol, famciclovir, fenoprofen, ibuprofen, primidone, progesterone and testosterone) based on the criteria of their prescription volumes in both private and public health sector in South Africa. The development of a sensitive and reliable analytical method for the simultaneous determination of PPCPs in aquatic samples was carried out; using a combined solid-phase extraction (SPE) isolation and clean-up, followed by derivatization prior to GC/TOFMS determination. A seven points concentration levels linear calibration curve with correlation coefficient (R2) ranged from 0.9988 to 0.9999 was obtained. The limits of detection (LOD) and the limit of quantification (LOQ) ranged from 0.01-0.27 μg L-1 and 0.03-0.91 μg L-1 respectively for target PPCPs. Repeatability studies gave % RSD within 3.41 – 11.72 % for peak area. The % RSD values for reproducibility studies were 2.88 – 9.91% for peak area over the three concentrations (ibuprofen: 0.4, 2 and 8 μg L-1) evaluated during 5 days. These results indicated that the proposed method has excellent precision as evidenced by very stable peak area for the analytes. The recovery testing carried out, exhibited recoveries ranging from at least 82-115% and 81-115 % in tap water and Milli-Q water respectively, with % RSD less than 12%, showing that the overall PPCPs determination method including the extraction procedure was a repeatable method.. The method was applied to target PPCPs from Daspoort influent and effluent wastewater in Pretoria (South Africa). Natural hormones and antiviral drug were not detected in all the samples analysed by this method. Bisphenol A, acetaminophen, carbamazepine, ibuprofen and diclofenac were detected at low concentrations, ranging from 0.052-135.42 μg L-1 in wastewater. The level of bisphenol A, primidone, carbamazepine, ibuprofen and diclofenac in effluent wastewater were found to be lower in comparison to the influent. Several other non-target compounds, such as benzophenone, caffeine, methocarbamol, efavirenz, atrazine, dioxaphetyl butyrate, nevirapine, androsta-1,4-diene-3,17-dione, cis-tramadol, batyl alcohol, paredrine, 7-acetyl-6-ethyl-1,1,4,4-tetramethyltetralin, propylparaben, eugenol, cholesterol, stigmasterol, guaifenesin, benzyl benzoate, 4-tert-octylphenol, diethyltoluamide, dicyclomine, terbuthylazine, spiroxamine, bis(2-ethylhexyl) phthalate, bumetrizole , were also detected in the wastewater sample using the developed method. / Chemistry / M. Sc. (Chemistry)

The ubiquitous presence of anthropogenic chemicals and their transformation products in surface water represents a toxicological concern from both an ecological standpoint and a human perspective as many of these chemicals are capable of altering hormonal function. Endocrine disrupting compounds can be traced back to numerous sources and may fall under the class of pesticide, industrial chemical, pharmaceutical, personal care product, and/or heavy metals. The adrenal gland is the most common target for endocrine disruptors, although in comparison to the sex steroids, this system has received much less attention in published research. Corticosteroids play a pivotal role in many physiological processes, including immunity, cognitive function, growth, metabolism, reproduction, mineral balance, and blood pressure. A primary cell culture of rainbow trout adrenocortical cells was used to investigate the endocrine disrupting activity of two commonly detected water-borne toxicants, a personal care product, triclosan (TCS), a pesticide, dichlorophenoxyacetic acid (2,4-D), and their transformation products, methyl-triclosan (M-TCS) and dichlorophenol (DCP). Previously, it has been shown that TCS, 2,4-D, and DCP exhibit a potential for endocrine disruption, although it is currently unknown if these chemicals are capable of affecting corticosteroid balance. In this study, all four chemicals showed significant inhibitory effects on corticosteroid synthesis, even though there were considerable differences in their activity. The chemical that exhibited the highest toxicity was 2,4-D, followed by TCS, DCP, and M-TCS. Both parent-compounds proved to be more toxic than their degradation products. More research with suitable test systems is needed to determine the mechanism(s) of action of these corticosteroid disruptors and the health risk that they may present. / ix, 139 leaves : ill. ; 29 cm

Indiana University-Purdue University Indianapolis (IUPUI) / 17-β estradiol (E2) exerts protective effects in hypoxia-induced pulmonary hypertension (HPH) via endothelial cell estrogen receptor (ER)-dependent mechanisms. However, the effects of hypoxia on ER expression in the pulmonary-right ventricle (RV) axis remain unknown. Based on previous data suggesting a role of ER-β in mediating E2 protection, we hypothesized that hypoxia selectively up-regulates ER-β in the lung and pulmonary endothelial cells. In our Male Sprague-Dawley rat model, chronic hypoxia exposure (10% FiO2) resulted in a robust HPH phenotype associated with significant increases in ER- β but not ER-α protein in the lung via western blotting. More importantly, this hypoxia-induced ER-β increase was not replicated in the RV, left ventricle (LV) or in the liver. Hence, hypoxia-induced ER-β up-regulation appears to be lung-specific. Ex vivo, hypoxia exposure time-dependently up-regulated ER-β but not ER-α in cultured primary rat pulmonary artery endothelial cells (RPAECs) exposed to hypoxia (1% O2) for 4, 24 or 72h. Furthermore, the hypoxia induced ER-β protein abundance, while not accompanied by increases in its own transcript, was associated with ER-β nuclear translocation, suggesting increase in activity as well as post-transcriptional up-regulation of ER-β. Indeed, the requirement for ER-β activation was indicated in hypoxic ER-βKO mice where administration of E2 failed to inhibit hypoxia-induced pro-proliferative ERK1/2 signaling. Interestingly, HIF-1α accumulation was noted in lung tissue of hypoxic ER-βKO mice; consistent with previously reported negative feedback of ER-β on HIF-1α protein and transcriptional activation. In RAPECs, HIF-1 stabilization and overexpression did not replicate the effects of ER- β up-regulation seen in gas hypoxia; suggestive that HIF-1α is not sufficient for ER-β up- regulation. Similarly, HIF-1 inhibition with chetomin did not result in ER-β down-regulation. HIF-1α knockdown in RPAECs in hypoxic conditions is currently being investigated. Hypoxia increases ER- β, but not ER-α in the lung and lung vascular cells. Interpreted in context of beneficial effects of E2 on hypoxic PA and RV remodeling, our data suggest a protective role for ER-β in HPH. The mechanisms by which hypoxia increases ER-β appears to be post-transcriptional and HIF-1α independent. Elucidating hypoxia-related ER-β signaling pathways in PAECs may reveal novel therapeutic targets in HPH.

This study is non-empirical and is based on the conceptualisations and theoretical foundations that gave rise to the global issue of sustainable development. It also traces the evolution and meaning of sustainable development in the South African socio-cultural context, and shows how the legacies of colonialism and apartheid contributed towards the national policy of sustainable development. This study explains the reasons for the presence (or lack) of sustainable development paradigms in apartheid and post-apartheid South Africa, as well as their implications for the future development of the country as a whole. There is also an analysis of the effects of the liberalisation of the water sector on the citizenry, and how this can disempower millions of poor South Africans. Finally, this study offers solutions for the lack of sustainable use of water in South Africa. Amongst the findings and conclusions are the deleterious effects of employment equity, cut-backs in municipal funding that resulted in the outsourcing of critical services such as water provision, and the deployment of party cadres to local councils. / Human Resources / M.A. (Development Studies)

This study is non-empirical and is based on the conceptualisations and theoretical foundations that gave rise to the global issue of sustainable development. It also traces the evolution and meaning of sustainable development in the South African socio-cultural context, and shows how the legacies of colonialism and apartheid contributed towards the national policy of sustainable development. This study explains the reasons for the presence (or lack) of sustainable development paradigms in apartheid and post-apartheid South Africa, as well as their implications for the future development of the country as a whole. There is also an analysis of the effects of the liberalisation of the water sector on the citizenry, and how this can disempower millions of poor South Africans. Finally, this study offers solutions for the lack of sustainable use of water in South Africa. Amongst the findings and conclusions are the deleterious effects of employment equity, cut-backs in municipal funding that resulted in the outsourcing of critical services such as water provision, and the deployment of party cadres to local councils. / Human Resources / M.A. (Development Studies)