Why does my urine smell like fries

On the trail of the outdoor pool smell Chlorine smell? Pee in the swimming pool

When it comes to swimming pools, we can smell it straight away: the smell of summer, that unforgettable mix of chlorine, sun cream and red and white French fries. What we prefer not to think about is the pee in the water. Some people in the swimming pool save themselves the trip to the toilet and simply pee in the water, true to the motto "Nobody notices". Are you kidding me? Are you serious when you say that!

For a study in 2017, Canadian scientists examined 31 different swimming pools and thermal baths over a period of three weeks. They were able to detect the urine indirectly but clearly by looking for a specific molecule, acesulfame. It only gets into the water by peeing. Accordingly, urine is found in every public swimming pool, without exception.

Every swimming pool is peed - every day

For large 50-meter pools, the researchers were able to detect an average of 75 liters of urine. In smaller 25-meter pools, it was at least about 30 liters of pee. That is not much in itself, there is one liter of urine for every 11,000 liters of water. But the study results suggest that the pee content is refreshed daily. Nothing is known about the pool peeers themselves: the scientists did not provide any information on whether young, old, girls or boys tend to get stuck in the toilet once they are in the water.

The warmer the water, the higher the concentration

However, the concentration of the molecule in thermal baths was significantly higher. Warm water seems to encourage bathers to just let it run. The scientists found a concentration three times higher in a jacuzzi than in the dirtiest swimming pool. Urine is sterile, but it contains urea, ammonia and creatine, among other things. In interaction with disinfectants in swimming water, they form by-products such as dibutyl phthalate. This is an emollient that can cause eye irritation and asthma attacks - a common problem with frequent swimmers.

Chlorine is actually odorless

If there is a particularly strong smell of chlorine in the swimming pool, that does not mean that the water is particularly clean. On the contrary. The chemical that kills germs in bath water is odorless. Only together with another substance does the typical ode arise:

If there is a strong smell of chlorine, it means that a lot of urea has been added to the water,

says Alexander Kampf, head of department for swimming and bathing pool water at the Federal Environment Agency in Dessau.

Pee clouds in the water: a long-lived myth

With their work, the Canadian scientists wanted to make a contribution to swimming pool hygiene in order to be able to provide information. They also speculate that it will be possible in the future to make urine in swimming pools visible. Contrary to persistent rumors, it has not yet been possible to catch peeing swimmers by discoloring their urine and betraying them by a pee cloud.