Magister Scientiae (Medical Bioscience) - MSc(MBS) / Exposure to endocrine-disrupting chemicals as bisphenol A (BPA) during gestation and early postnatal life is known to disrupt normal developmental processes and alter the body’s endocrine system leading to deleterious effects in the developing central nervous system (CNS). BPA is an industrial synthetic chemical commonly used in the production of a range of polymers and consumer products, despite concerns about its safety. There is therefore the need to protect the developing CNS from potential damage through the administration of neuroprotective agents. Most medicinal plants are reported to possess significant protective potential against tissue damage through different mechanisms that prevent cell death, oxidative stress, inflammation, immunodeficiency, etc. In this study, the protective effects of fermented rooibos (Aspalathus linearis) tea against the deleterious effects of BPA were investigated. Rooibos is a herbal beverage indigenous to South Africa with widely acclaimed health benefits often linked to the bioactivity of its polyphenolic compounds, especially aspalathin. The anti-allergic, cardiovascular, antioxidant and neuroprotective effects of this herb have been previously reported hence, the present study aims to investigate if regular consumption of rooibos tea during pregnancy and lactation could protect the developing brain from the deleterious effects of BPA in a Wistar rat model. A total of 40 three-month old adult female pregnant dams, with an average weight of 250g, were divided into four groups (n=10). Group 1 control rats received 9% normal saline ad libitum; group 2 rats received 400μg/kg/day BPA only; group 3 rats received 20% fermented rooibos tea as well as 400μg/kg/day BPA, while group 4 rats received ad libitum 20% fermented rooibos tea only. Offspring rats were housed in the same cages as the dams and only separated after weaning on postnatal day (PND) 21. Neurobehavioural assessment using the open field test was done on postnatal day (PND) 42 after which the final body masses were taken before the rats were decapitated under deep anaesthesia, and the desired CNS parts carefully dissected out and processed for histological, biochemical and immunohistochemical studies. The results obtained showed that there was significant impairment of neurobehavioural activity, decreased cerebral and cerebellar antioxidant enzyme activity, reduced hippocampal CA1 length, significant loss of cerebellar Purkinje cells and significant astrocyte activation demonstrated by increased glial fibrillary acidic protein (GFAP) activity in experimental rats exposed to BPA only. However, co-administration of rooibos tea significantly attenuated the BPA-induced distortions. Taken together, these findings suggest that rooibos could be a potent neuroprotective agent against BPA-induced structural, functional and biochemical alterations in the developing CNS.

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Endocrine disrupting chemicals (EDCs) are ubiquitous in the environment and have been detected in drinking water. Although various water treatment processes can remove EDCs, chemicals can migrate from pipes that transport water and contaminate drinking water. Globally bottled water consumption is steadily rising as an alternative to tap water, but EDCs have also been detected in bottled water. Sources of EDCs in bottled water include contamination of the water source, contamination through the production process or the migration of EDCs from the packaging material. There is limited information on EDCs in drinking water and bottled water from South Africa. The aim of this study was to determine the estrogenic activity, levels of selected EDCs and the potential health risks associated with the consumption of water from selected distribution points in Pretoria (City of Tshwane) and Cape Town as well as bottled water. The study consisted of 3 phases. Phase 1 included the analysis of drinking water samples from ten water distribution points in Pretoria and Cape Town collected over four sampling periods. In phase 2, ten brands of bottled water were analysed after exposure to different storage conditions (20°C, 40°C, light and dark) for 10 days. Samples were extracted using a C18 solid phase extraction method. Estrogenic activity was assessed using the recombinant yeast estrogen screen (YES) bioassay and the T47D-KBluc reporter gene bioassay. The extracts were analysed for di(2-ethylhexyl) adipate (DEHA), di(2-ethylhexyl) phthalate (DEHP), diisononylphthalate (DINP), dibutyl phthalate (DBP), bisphenol A (BPA), nonylphenol (NP), 17β-estradiol (E2), estrone (E1) and ethynylestradiol (EE2) using UPLC-MS. Phase 3 consisted of a scenario based health risk assessment to assess the carcinogenic and toxic human health risks associated with the consumption of distribution point and bottled water. All the samples were below the detection limit (dl) in the YES bioassay, but estrogenic activity was detected in bottled and distribution point water using the T47D-KBluc bioassay. All samples were below the 0.7 ng/L trigger value for estrogenic activity in drinking water. NP was below the dl for all the samples, E2 was detected in five distribution point samples and E1, EE2, DEHA, DEHP, DINP, DBP and BPA were detected in distribution point and bottled water samples. The estrogenic activity and levels of target chemicals were comparable to the levels found in other countries. Hazard quotients for BPA, DEHA and DINP were higher in bottled water compared to distribution point water. The greatest non-carcinogenic health risk was posed by E1 in distribution point water from Pretoria and the highest cancer risk by levels of DEHP in distribution point water from Cape Town. However, overall, health risk assessment revealed acceptable health and carcinogenic risks associated with the consumption of distribution point and bottled water. Although the potential health risks posed by the EDCs found in the water samples in this study were low, the fact that potential EDCs were found in the water samples are still of concern. A monitoring strategy that also includes water from other municipalities and other brands of bottled water are therefore recommended. / Thesis (PhD)--University of Pretoria, 2016. / School of Health Systems and Public Health (SHSPH) / PhD / Unrestricted

abstract: Endocrine disruptors are chemicals that interact with the hormone system to negative effect. They ‘disrupt’ normal processes to cause diseases like vaginal cancer and obesity, reproductive issues like t-shaped uteri and infertility, and developmental abnormalities like spina bifida and cleft palate. These chemicals are ubiquitous in our daily lives, components in everything from toothpaste to microwave popcorn to plastic water bottles. My dissertation looks at the history, science, and regulation of these impactful substances in order to answer the question of how endocrine disruptors appeared, got interpreted by different groups, and what role science played in the process. My analysis reveals that endocrine disruptors followed a unique science policy trajectory in the US, rapidly going from their proposal in 1991 to their federal regulation in 1996, even amid intense and majority scientific disagreement over whether the substances existed at all. That trajectory resulted from the work of a small number of scientist-activists who constructed a concept and category as scientific, social, and regulatory. By playing actors from each sphere against each other and advancing a very specific scientific narrative that fit into a regulatory and social window of opportunity in the 1990s, those scientist-activists made endocrine disruptors a national issue that few could ignore. Those actions resulted in the Endocrine Disruptor Screening Program, a heavily-criticized and ineffective regulatory program. My dissertation tells a story of the past that informs the present. In 2018, the work of researchers, public media, and policymakers in the 1990s continues to play out, evident in the deep scientific division over endocrine disrupting effects and the inability of the European Union to settle on even a definition of endocrine disruptors for regulation purposes. / Dissertation/Thesis / Doctoral Dissertation Biology 2018

Today, assessment of the health of coastal waters is recognized as being important for both the conservation of nature and well-being of humans. Anthropogenic pollution has been the focus of extensive research for some time and a variety of programs for the monitoring and assessment of environmental pollution have been developed. Determination of the levels of pollution in sensitive ‘sentinels’ such as mussels, allows monitoring of these levels in a given area over a prolonged period of time. Furthermore, the biological effects of pollution are reflected in a series of biomarkers, none of which provides a general picture of the sentinel’s state of health and all of which are individually specific for certain pollutants and influenced by both biotic and abiotic factors. In an attempt to improve biomonitoring of marine pollution, we have developed two proteomic approaches here. In the first portion of the thesis, a proteomic analysis was performed on peroxisomes isolated from mussels exposed either to one of three model anthropogenic pollutants, or two different types of crude oil, or from mussels exposed to the Prestige oil spill. Application of two-dimensional electrophoresis (2-DE) provided protein expression signatures (PES) for exposure to these different pollutants.Furthermore, several individual protein components of these PES could be putatively identified. In the second portion of this work, such analysis of subproteomes was developed further in order to improve the applicability of this approach to biomonitoring. A simple fractionation procedure in combination with liquid chromatography and 2-DE provided samples from mussels residing in different regions of a pollution gradient around the harbor of Gothenburg, as well as from mussels exposed to two types of fuel oil similar to that of the Prestige that were suitable for environmental proteomics. In addition, we constructed a model for this approach that can be cross-validated in the future and applied to assess sources of fuel oil pollution in connection with biomonitoring programs.

Magister Scientiae - MSc (Chemistry) / Pollutants such as polycyclic aromatic hydrocarbons (PAHs) are known for their toxic effects which may lead to the cause of degenerative diseases in both humans and animals. PAHs are widespread in the environment, and may be found in water, food, automotive industry and petrochemical industries to name but a few sources. Literature reports have highlighted industrial workplace exposure to PAHs as a leading cause for development of cancer in workers. Particularly, workers in the petrochemical industry are adversely affected and the incidence of skin and lung cancer in this population group is high. The United States of America in its guidelines developed by environmental protection agency (EPA) has identified 18 PAHs as priority pollutants. Among these are anthracene, benzo[a]pyrene and pyrene which have been selected as the focal point of this study due to their significance in the petrochemical industry. Due to the carcinogenic and mutagenic properties reported in literature for certain PAHs, there have been monitoring procedures taken in most countries around the world. The commonly used analytical methods for the detection of PAHs from industrial samples are high performance liquid chromatography (HPLC) coupled to fluorescence detection, membrane filtration, ozonation and reverse osmosis. Analysis of PAHs from the petrochemical industry is typically performed by HPLC method as well as sono-degredation in the presence of oxygen and hydrogen peroxide.

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