Hikers in French Pyrenees hospitalised after drinking mountain water
Why water from a mountain stream is not always safe to drink from and how to avoid dehydration
Published
Several hikers fell ill in the Hautes-Pyrénées and had to be evacuated by mountain rescue teams after drinking water collected from mountain streams and lakes. The hikers were using filtering bottles.
Nine hikers were evacuated on July 14, after developing symptoms including nausea, vomiting and diarrhoea following the consumption of the untreated water, according to La Dépêche du Midi.
The hikers were in two separate groups. A group of five was rescued near the Refuge de la Glère, close to Barèges in the Néouvielle massif. The other group of four hikers was assisted near Lac de Bastan, close to Aragnouet in the Aure valley. Both groups were flown by helicopter to Tarbes hospital.
Clear mountain water is not always safe
Mountain streams and lakes can appear clean but they may contain microorganisms that can cause illnesses. Water can be contaminated with bacteria, viruses, or parasites from wildlife, grazing animals, human activity, or pollution.
This is why the water quality cannot be assessed only by appearance.
The prefecture des Hautes-Pyrénées has also warned that water from mountain streams and torrents can contain contaminants that may cause illness.
“Do not drink water from mountain streams and torrents, even with filtered water bottles!” it said in a Facebook post.
The prefecture recommended that hikers carry enough drinking water before setting out and use reliable sources, such as water points at refuges, when they need to refill. “In hot weather, allow 1/2 litre of water per hour of walking,” it said.
How to stay hydrated during a mountain hike
During hot weather, dehydration can become a serious risk, particularly during long or demanding walks.
The French Hiking Federation’s (FFRandonnée) recommendations include:
Carry enough drinking water for the planned route
Drink regularly throughout the walk
Plan refill points before setting out, using reliable sources such as refuges
Avoid the hottest parts of the day and take regular breaks in the shade
If there is no other option, the only way to make the water drinkable is to boil it, at least for a minute and at least for three minutes at an altitude above 2,000m. But for this, hikers must carry a camping stove.
As for water bottles, they should be used with caution when no other drinking water source is available, as their effectiveness depends on the type of contamination present.
What to do if you become ill after drinking mountain water
Symptoms after drinking untreated mountain water can include nausea, vomiting and diarrhoea. These symptoms can lead quickly to dehydration, especially during a mountain walk in hot weather.
If a hiker’s condition deteriorates and they are no longer able to continue, emergency services should be contacted promptly. In France, hikers can call 15 or 112, the European emergency number for emergency assistance.
Mountain rescue services may also use location systems such as GendLoc to help identify a caller’s position.
