The use of aluminium oxide is an effective and safe method for the removal of fluoride from natural mineral waters, an EU scientific body has concluded.
The evaluation of various methods to remove fluoride from such products paves the way for regulator approval of the process. This would provide companies with an EU-wide approved process to meet regulatory requirements on the mineral levels allowed for bottled natural mineral and spring waters.
The report was commissioned by the European Commission at the request of some member states. It will now go to the European Food Safety Authority (EFSA) for further scientific evaluation, before being approved EU-wide.
Under EU law, treatments of natural waters must not change the essential characteristic of the product.
The scientific panel concluded that activated alumina media provides an efficient process for defluoridation of natural mineral waters, even with high fluoride concentration, if appropriate media and operating conditions are used;
”The activated alumina treatment does not cause any significant change of the characteristic composition of NMW (natural mineral waters) when appropriate operating conditions are maintained,” the report stated.
The panel recommended that to avoid te release of substances into the water, activated alumina media, chemical reagents and materials should comply with the European standards and, where necessary, national drinking water treatment standards.
The panel found that some aluminium is released in the treated water, but this can be kept to a minimum under the right processes. Other substances used with the aluminium treatment did not show up significantly in the water, provided good operating conditions are maintained.
For each natural mineral water treatment, bottlers should examine if a pre-treatment for the removal of other substances — such as iron, manganese or arsenic — is required prior to defluoridation, the panel stated.
Only three treatments are eligible for fluoride natural mineral water defluoridation in the EU, including the use of activated alumina. In the past, bauxite, a mineral containing aluminium oxide, was used for fluoride removal.
However the treatment had the disadvantage in not being able to guarantee optimal fluoride reduction. There was also a risk of undesirable contaminants being released from the bauxite.
In the EU only synthetic alumina has been tested at large scale to remove fluoride from natural mineral water.
The use of apatite, another approved process, involves only synthetically manufactured hydroxyapatite. The process has been used on an experimental basis for about two years, and is still under development, the panel reported.
Its eligibility for EU authorisation will be assessed in the future when all necessary data are available, the panel stated.
The use of manganese oxide is also under development at the experimental level.
Natural mineral waters and spring waters may be treated at source to remove unstable elements and some undesirable ingredients in compliance with an EU directive.
Other fluoride removal methods, including precipitation through decantation treatments, membrane filtration and ion exchange treatments are not approved for use as they change the characteristic of the water.
Treatments other than filtration with possible oxygenation have to be assessed and authorised at the EU level prior to their use by industry. The Commission and EFSA have been working together to evaluation commonly used treatments for various minerals.
Natural mineral waters are one class of bottled waters sold under regulation in the EU. They are defined by their purity at source and their constant level of minerals. A Commission directive of 16 May 2003 established a list of approved sources, concentration limits and labelling requirements for the constituents of natural mineral waters.
It also established the conditions for using ozone-enriched air for the treatment of natural mineral waters and spring waters.
The lists of mineral waters officially recognised by the member states of the EU and by Iceland and Norway are published by the European Commission in an official journal.