Mineral water producers are up in arms over a report claiming that tests had found bottled water to be potentially toxic and loaded with heavy metals, firing back with their own research.

The latest report, published in Food Review, is in response to results published by the Sefako Makgatho Health Sciences University in Pretoria towards the end of 2022.

That report, issued on 16 November, noted bottled water was one of the fastest-growing commercial products in both developing and developed countries owing to the belief that it was safe and pure. And yet it said the water tested was anything but safe and pure.

In South Africa, the authors of the Sefako report wrote, sales of bottled water were driven by the perception that water supplied by the government might not be safe for human consumption. The study investigated concentrations of trace metals and the physico-chemical properties of bottled water bought from various supermarkets in Pretoria to determine health risks.

Twelve commonly available brands of water were purchased and analysed for trace-metal content. Three of the samples had pH values in the acidic region below the permissible standard of 6.8–8.0 set by the International Bottled Water Association, meaning they were not fit for human consumption. The target hazard quotient calculated for the water samples showed a minimum risk for lead, chromium and nickel.

Chromium is harmful to the skin, eyes, blood and respiratory system. Nickel exposure can harm the lungs, stomach and kidneys, and can lead to cancer.

Lead exposure can have serious consequences, especially for children. At high levels of exposure, lead attacks the brain and central nervous system, causing coma, convulsions and even death. The WHO says children who survive severe lead poisoning may be left with intellectual disability and behavioural disorders.

Analysed brands

The brands analysed at the Sefako Makgatho Health Sciences University in Pretoria North, were labelled “natural spring water”, “prepared water” or “mineral water”. The samples were kept under cool conditions and transported to the laboratory, where it was stored at 4°C until the chemical analysis.

Information on the labels of some of the bottles did not match the chemical makeup of the water they contained, said the research team led by Professor Joshua Olowoyo.

Citing research by Gerassimidou et al, published in May 2022, the Pretoria researchers relied on evidence that in certain temperatures, chemicals have the potential to migrate from polyethylene terephthalate (PET) plastic bottles into the water as well as during recycling. It is also possible for the water to be contaminated from the source owing to variations in geological and geographical factors. 

Globally, because freshwater quality is deteriorating because of human activities such as mining effluent and accidental spills, freshwater systems in most developing countries are under pressure from harmful chemicals. Municipal water treatment facilities cannot remove these chemicals or other impurities completely from the water because it’s expensive, technology is dated and there has been an increase in demand for potable water supplies.

The study mapped food-contact chemicals that migrate from PET drink bottles to identify difficulties in closing the plastic packaging loop. 

The researchers have called for producers to be monitored for compliance with WHO limits and that suppliers should make analytical reports on water safety available to consumers.

‘Numerous errors’

The subsequent review by Calie Adlem, a former CSRI quality manager, and John Weaver, who has a master’s degree in hydrology, claims to have found “numerous errors and probable incorrect data”, including the use of incorrect units of measure; a lack of clarity about what was being tested/reported; and a lack of interrogation of the results. 

Weaver and Adlem have raised objections to the study, saying it errs on three fundamental levels.

They say the authors lack understanding of water chemistry; that they failed to interrogate the results; and that they misunderstood the testing protocols. They have also compared outdated water guidelines, referencing WHO 2007, when there is a 2017 (4th) version available for free online. “Perhaps the most irritating error made by the authors is a conceptual one,” Weaver said. “The WHO guidelines are for drinking water, whereas the waters analysed are bottled water. Bottled water is defined as a foodstuff, thus has separate regulations and standards being, in South Africa, R.718 of 28 July 2006: Regulations relating to all packaged water and SANBWA Packaged Water Standard: Requirements for Source Water, Processing and Packaging 2019. These have been based upon CODEX standards.”

Charlotte Metcalf, the CEO of the South African Bottled Water Association (SANBWA), added: “The data from this coalition and our own routine inspections shows a radically different scenario to [the] ‘Toxic in Pretoria’ findings. 

“Our members’ results for toxins and heavy metals are historically below the level of detection or very far below the maximum allowable limits. This is due to the diligent process of investigation and protection efforts prior to starting up a water-bottling plant. Unsafe sources are not allowed to be bottled in the SANBWA fold.

“We are confident that SANBWA members’ water conforms to all relevant legislation and is safe for human consumption. The best way for consumers to protect themselves from unscrupulous bottlers is to look for the SANBWA logo on a bottle of water.”

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In Spain, scientists at the Barcelona Institute for Global Health found the impact of bottled water on ecosystems to be 1,400 times higher than tap water and if the city’s population were all to drink bottled water, this would result in a 3,500 times higher cost of resource extraction than if they all drank tap water, at £60.3-million (R1.3-billion) a year.

In Spain, bottled water is becoming increasingly popular, despite improvements to the quality of tap water in recent years.

Lead author of the Spanish study, the ISGlobal researcher Cristina Villanueva, said: “Health reasons don’t justify the wide use of bottled water. Yes, strictly speaking, drinking tap water is worse for local health, but when you weigh both, what you gain from drinking bottled water is minimal. It’s quite obvious that the environmental impacts of bottled water are higher compared to tap water…

“People trust bottled water because advertisers have done a good job of convincing people it’s a good option, so we need the effort on the other side.”

Harvard University in the US reports that 17 million barrels of oil are needed to produce the plastic to meet the annual demand for bottled water and that bottled water is about 3,000% more expensive per gallon (3.8 litres) than tap water.

In the UK, bottled water is at least 500 times more expensive than tap water.

South Africa’s bottled water segment is expected to reach volumes of about 2.5 million litres by 2027. BM/DM