There are two types of sewer systems - storm sewers and sanitary sewers.  Sanitary sewers take water from showers, dishwashers, and washing machines – known as grey water - away for treatment, while storm sewers deal with rain water by returning it to natural waterways.

It’s a big problem when grey water finds its way into the ecosystem via broken pipes and bad plumbing.

Speaking to Newstalk, Professor David Lerner who published the study along with his student Dave Chandler told us how the idea came about.

“I’ve been seeing the problem of diffuse pollution a lot, which is basically lots of little bits and pieces of waste in the water system. Dave needed a way to identify optical brighteners in the water, and he came up with the idea of using tampons to do so – Tampons are untreated cotton, so they’re perfect”.

Optical brighteners are compounds used in detergents to make clothes as white as possible. They glow under UV light, and so tampons provide the perfect body for these compounds to latch on to.

The researchers tied tampons to the ends of bamboo and held then down into the water, before examining them under a UV light.  Using the technique, they tested 16 samples of surface water, identifying pollution in 9 of them.

There has never been a cheaper, easier way to test surface water and find the source of pollution. Once grey water is detected within a sample, testing continues up the sewer until the source of the pollution is found.

Professor Lerner told us that he will be using this technique within his own community.

“I chair a citizens group in Bradford. We’re going to use this method to find out the sources of pollution in our river as a citizens science project.”