Which is safer to drink: tap water or bottled water? Both, it turns out, according to recent research by Dr Catherina van Zijl, a senior medical natural scientist, of the environmental chemical pollution and health research unit at the University of Pretoria.
The focus of her research, conducted as part of her PhD study under the supervision of Professor Tiaan de Jager and Dr Natalie Aneck-Hahn, was a comparison of the estrogenic activity and levels of oestrogens, bisphenol A (BPA), nonylphenol (NP) and phthalates between tap and bottled water.
These endocrine disrupting chemicals (EDCs), which mimic natural hormones, have been reported in tap and bottled water from various countries, says the University of Pretoria, in an article on her work.
Van Zijl evaluated 10 distribution points of tap water in Pretoria and 10 in Cape Town. She collected 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, ensuring the water came from a variety of sources such as spring water and dolomite lakes and treated water from different areas.
Her results revealed that estrogenic activity was higher in tap water, which indicated water treatment facilities were not able to remove all the activity.
BPA, DINP (a phthalate) and EE2 (synthetic hormone) were higher in bottled water and estrogenic activities increased in some of the bottled water when exposed to increased temperature of 40°C.
Estrogenic activity and concentrations of EDCs found in bottled water were comparable to other countries.
“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,” says the university.
While bottled water consumption in SA stood at 8.3 litres per capita in 2012 compared to global average consumption of 35 litres per capita, “a dramatic 315% growth in consumption of bottled water in SA was seen from 1999 to 2012”, says Van Zijl.
She advises against the reuse of PET bottles because “this increases the chances for chemicals to leach into the water.
Make sure your bottle does not contain PVC (do not use bottles with no 3 recycling code on the bottle) And recycle.”