Tadpoles light the way to cleaner water

The tadpoles light up in contact with micropollutants. oliver.dodd via flickr

How to check for micropollutants in our drinking water? With fluorescent tadpoles, of course! The Swiss city of Lausanne is piloting a new method for testing its water supplies.

The tadpoles in question are genetically modified to light up luminously when they come in contact with endocrine disruptors present in water – the level of their brightness generally corresponding to the level of micropollutants present.

Following initial roll-outs in Brussels, the Swiss city of Lausanne is now using the technique to check up on its drinking water: concretely, by throwing a posse of 50 tadpoles into water samples from pumping and purification centres, before analysing their luminosity.

The results? So far, as expected. The larva light up like beacons when coming in contact with the dirty water arriving at the purification centre, while the supposedly clean water coming from Lake Geneva is backed-up by the weak light of the tadpoles.

Froggy style

The technique will contribute to better analysing the level of endocrine disruptors, micropollutants whose effects on health are not yet well understood, but which have been shown to contribute to various developmental disorders.

The tadpole indicators will allow engineers to strengthen filtration systems for dirty water heading back towards Lake Geneva.

“In terms of drinking water, this could help raise the alarm and thus allow us to cut off water supplies to investigate whether there is a problem of pollution in the source water or treated water,” said Christophe Méchouk of the water service of Lausanne to Swiss public broadcaster, RTS.

The city of Geneva, according to RTS, may be next in line to test this latest technique, developed by French start-up Watchfrog.

swissinfo.ch with agencies/dos