Generations of walkers and backpackers have used iodine to treat water taken from mountain streams

Iodine, for many years used by walkers and mountaineers to disinfect water, will be banned in the European Union from autumn.

The ban means that, from 25 October retailers will no longer be allowed to sell or supply for use the substance. Some equipment manufacturers will also need to modify their gear in response to the ban. Chlorine tablets will still be available for the purpose.

The ban affects all 27 EU countries and was taken in response to US Center for Disease Control advice which says iodine should only be consumed in controlled doses for no more than a few weeks.

Pregnant women and those with thyroid problems were always advised against using the substance.

Generations of outdoors enthusiasts, military personnel and travellers have used iodine, producing its telltale yellow colouring, to kill bugs in drinking water. Alternatives include, as mentioned, chlorine tablets, though these produce a strong ‘swimming bath’ taste in treated water; boiling and devices using ultra-violet light and filtering.

The main risks from drinking untreated water come from bacteria, viruses and parasites such as giardia and cryptosporidium. There may also be chemicals present in water, though this is less likely in high mountain streams.

Industry insiders said the move could be followed by the United States and other countries.