Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings. Although Olympic swimmers have admitted doing it and 19 per cent of adults have admitted to urinating in a pool at least once, it is not a condoned practice.The average urine excretion per swimmer in pools is approximately 70ml.Despite urine itself being sterile, compounds can react with disinfectants such as chlorine causing them to become volatile – after which exposure can lead to eye and respiratory irritation and has been linked to occupational asthma. Dr Xing-Fang Li, from the University of Alberta, Canada, say this evidence has highlighted the need for improved understanding of pool chemistry to raise awareness and educate the public on the importance of swimming hygiene practices.The researchers tested more than 250 water samples from 31 actively used pools and hot tubs in two Canadian cities and more than 90 samples of clean tap water used to initially fill the basins.The concentration of ACE in the pools and hot tubs ranged from 30 to 7,110 nanograms per liter of water – up to 570 times more than the levels found in the tap water samples. “The high concentration of ACE with 100 per cent occurrence in pools and hot tubs demonstrates the human impact on recreational water quality.”The association of occupational asthma in swimmers with volatile disinfection byproducts (DBP) highlights the need to control the water quality of swimming pools.”Several studies have reported that increased dissolved organic in swimming pools results in enhancement of DBP formation.”To reduce exposure to N-DBPs and their negative health impacts in swimming pools, we should monitor and control water quality.”The findings were published in the journal Environmental Science and Technology Letters. Swimmers in an Olympic-sized pool could be surrounded by up to 50 gallons of urine, a new study has revealed.Scientists used an artificial sweetener found in urine to measure how much pee is in swimming pool water.They discovered the sweetener acesulfame potassium (ACE), is consistently present in urine, making it easy to monitor pool levels.In tests they found a 91,500 gallon pool contained 5.8 gallons of urine and a 183,000 gallon pool, a third the size of an Olympic pool, was awash with around 17 gallons. Many olympic swimmers admit to peeing in the poolCredit:AP Photo/Lee Jin-man Dr Xing-Fang Li said: “This is the first reported occurrence study of ACE in swimming pools and hot tubs.