The South African National Bottled Water Association (SANBWA) has challenged the accuracy – and therefore the validity – of ‘Tests find toxic bottled water in Pretoria’ research.
It tasked respected hydrogeologist (MSc University of Free State) John Weaver, and the ex-head of one of the CSRI’s top analytical laboratories in South Africa, Calie Adlem, to review the results published in December last year.
Weaver’s review, which was supported by Adlem, found numerous errors and probable incorrect data, including:
- Use of incorrect units of measure – for example, in Table 1 the units used for EC should be µS/cm (microSiemens/centimetre) – definitely not mS/m
- Lack of understanding of water chemistry or a ‘feel’ for water – for example, the authors state that ‘EC determines the ability of the water to conduct electricity and is a function of the levels of Ca and Mg in water. The TDS on the other hand, determines the taste of the water if the concentrations are above the recommended limit of 1500 mg/L.’ This is incorrect: EC is a function of all the dissolved salts (ions) in the water, not just Ca and Mg.
- Lack of clarity about what was being tested/reported – for example, in the method statement the authors state that they ‘digested’ the samples by adding Nitric Acid. This means they analysed for Total Iron, and not just Dissolved Iron. This should have been stated.
- Lack of interrogation of the results – for example, in the discussion about FE or Total Iron, for sample #8, the EC is 3 µS/cm and the TDS is 2 mg/l. With these very low levels of TDS this cannot be a Natural Water (as claimed by the authors), but must be water that has been subjected to reverse osmosis. Given that Fe is a relatively large molecule, and would have been totally removed by reverse osmosis, the authors should not have found Fe in sample #8. This anomaly should have been stated and interrogated. Furthermore, at the levels of FE stated in Table 2, the waters would have presented a very ‘irony’, ‘rusty tin can flavour’. The authors did not query why such ‘unpleasant tasting waters’ – all 12 of them – would have found favour with the consumers in Pretoria.
- Analytical errors – for example, table 2 shows values ranging from 142.53 µg/L to 164.70 µg/L, with one outlier at 190.26 µg/L. This very tight range of excessively high values is extremely suspicious, and most likely an analytical error.
- Misunderstanding of testing protocols – for example, Chrome occurs in three forms: Cr or Cr-0 (chromed metal and stainless steel), Cr3+ or Cr-3 (the common dissolved chrome), and Cr6+ or Cr-6 (toxic, and therefore the only ion of concern). The analysis for Cr-6 is specialised and water samples must be analysed within 24 hours of collection. Buying bottles off the shelf does not qualify for this testing. Further, the samples tested by the authors were kept for periods longer than 24 hours.
- Comparison against outdated guidelines – for example, the authors reference WHO 2007, when there is a 2017 (4th) version available online, and free of charge.
“Perhaps the most irritating error made by the authors is a conceptual one,” said Weaver. “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.”
Metcalf added: “The data from this collation and our own routine inspections shows a radically different scenario to ‘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.”
