Browsing by Author "Hendricks, Rahzia"

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    The effectiveness of sewage treatment processes to remove faecal pathogens and antibiotic residues
    (TAYLOR & FRANCIS INC, 2013) Hendricks, Rahzia; Pool, Edmund John
    Pathogens and antibiotics enter the aquatic environment via sewage effluents and may pose a health risk to wild life and humans.The aim of this study was to determine the levels of faecal bacteria, and selected antibiotic residues in raw wastewater and treatedsewage effluents from three different sewage treatment plants in the Western Cape, South Africa. Sewage treatment plant 1 and 2 useolder technologies, while sewage treatment plant 3 has been upgraded and membrane technologies were incorporated in the treatmentprocesses. Coliforms andEscherichia coli(E. coli) were used as bioindicators for faecal bacteria. A chromogenic test was used toscreen for coliforms andE. coli. Fluoroquinolones and sulfamethoxazole are commonly used antibiotics and were selected to monitorthe efficiency of sewage treatment processes for antibiotic removal. Enzyme Linked Immunosorbent Assays (ELISAs) were used toquantitate antibiotic residues in raw and treated sewage. Raw intake water at all treatment plants contained total coliforms andE. coli.High removal ofE. coliby treatment processes was evident for treatment plant 2 and 3 only. Fluoroquinolones and sulfamethoxazolewere detected in raw wastewater from all sewage treatment plants. Treatment processes at plant 1 did not reduce the fluoroquinoloneconcentration in treated sewage effluents. Treatment processes at plant 2 and 3 reduced the fluoroquinolone concentration by 21%and 31%, respectively. Treatment processes at plant 1 did not reduce the sulfamethoxazole concentration in treated sewage effluents. Treatment processes at plant 2 and 3 reduced sulfamethoxazole by 34% and 56%, respectively. This study showed that bacteria and antibiotic residues are still discharged into the environment. Further research needs to be undertaken to improve sewage treatmenttechnologies, thereby producing a better quality treated sewage effluent.
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    The use of in vitro assays to screen for endocrine modulation
    (University of the Western Cape, 2008) Hendricks, Rahzia; Pool, Edmund J.; Faculty of Science
    Aspalathus linearis (A. linearis), commonly known as Rooibos tea or Red bush tea and Camellia sinensis (C. sinensis) or Black tea are beverages that are consumed throughout the world. These teas possess antioxidant, immunomodulating and anti-cancer actions. The aim of this study was to use in vitro assays to screen Rooibos and Black tea for endocrine modulation. The immune modulating effects of Rooibos and Black tea were investigated using an in vitro whole blood culture (WBC) assay. Unstimulated WBCs treated with Rooibos tea secreted higher levels of IL-6, IL-10 and IFNγ than cultures treated with DMSO control. Rooibos treatment of stimulated WBCs resulted in higher IL-6, lower IL-10 and no effect on IFNγ secretion compared to DMSO treated stimulated WBC. Black tea treatment of stimulated WBC resulted in decreased IL-6, IL-10 and IFNγ secretion compared to the DMSO treated stimulated WBC. Extracts of Rooibos and Black tea were assessed for phytoestrogens using quantitative estrogen ELISAs. Both teas contain phytoestrogens. The quantitative ELISAs showed that Rooibos tea contained significantly lower estrone (E1), estradiol (E2) and estriol (E3) levels than Black tea. The effects of Rooibos and Black tea on proliferation of the estrogen dependant MCF-7 cell line was determined to further characterise the phytoestrogenic properties of the teas. Both Rooibos and Black tea extracts caused a significant inhibition of MCF-7 proliferation. This study shows that Rooibos tea and Black tea are beverages that can either stimulate or suppress the immune system. Also, both teas contain significant levels of phytoestrogens as determined by quantitative ELISAs. The current study confirms previous reports showing inhibition of growth in breast cancer cell lines by phytoestrogens. The findings extend related observations on the anti-carcinogenic potential of the two teas.