Page 22 - University of Pretoria Research Review 2017

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... Water and health
(US). The researchers have identified a novel and previously undescribed hepatitis A virus and high titres of sapoviruses in water sources destined for irrigation use, while an emerging norovirus GII.17 was detected in wastewater discharged into a dam used for recreational purposes. This information contributes to a better understanding of the epidemiology, dissemination
and potential health of these viruses in the aquatic environment. In 2017, findings in the field of enteric viruses and water virology were published in Infection Genetics and Evolution; Epidemiology and Infection, and the Journal of Water and Health.
Another research focus has been on treated drinking water. South Africa is one of the few countries in the world where tap water is still regarded as relatively safe to drink, particularly in cities. However, the maintenance of water treatment facilities is expensive and is not always carried out effectively – especially in smaller municipal areas.
Irrespective of the water treatment process, South Africa’s national drinking water quality guidelines predominantly focus on the microbial quality of the water to ensure the safety of drinking water. However, chemicals, which are not effectively removed by water treatment processes, get into water systems by way of direct discharge into water, sewage and wastewater effluent, leaching from landfill sites, agricultural and stormwater runoff and accidental spills. Long-term chronic exposure to some of these chemicals, known as endocrine-disrupting chemicals or EDCs, can have serious effects on people’s health and even the health of their progeny. Disorders related to EDC exposure range from genital malformations, obesity, Type 2 Diabetes and endocrine-related cancers including testicular, prostate, breast, ovarian, endometrial and thyroid cancers.
Dr Catherina van Zijl, a senior medical scientist of the ECPH Research Unit, evaluated the levels of selected EDCs in tap and bottled water in South Africa as part of her PhD study, supervised by Professor Christiaan de Jager and Dr Natalie Aneck-Hahn. The study, funded by the Medical Research Council (MRC), compared the oestrogenic activity and levels of oestrogens, bisphenol A (BPA), nonylphenol, and phthalates in tap and bottled water.
Van Zijl evaluated 10 distribution points of tap water in Pretoria and 10 in Cape Town, and collected water samples seasonally, to account for seasonal variations on the quality of water. She analysed 10 of the most popular bottled water brands in South Africa, making sure the water came from a variety of sources such
as spring water, dolomite lakes, treated water from different areas, and including different treatment methods. Tests included bioassays to indicate the
total oestrogenic activity of each sample, as well as chemical analysis to determine the concentrations of specific EDCs. The results showed that oestrogenic activity was higher in tap water, which indicated that water treatment facilities were not able to remove all the activity. BPA, DINP (phthalate) and EE2 (synthetic hormone) were higher in bottled water, and oestrogenic activities were increased in some bottled water when exposed to temperatures of 40°C.
However, health risk assessments revealed acceptable health and carcinogenic risks associated with the consumption of the water and these results compared well to other countries, giving both tap water and bottled water the green light. Van Zijl notes, however, that this study only tested for oestrogenic activity and not other hazardous chemicals that might affect the thyroid and androgenic activities in the human body. The tests were also only conducted in two large cities and smaller municipalities’ treatment processes may not be of the same standard.
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