Swimmers in an Olympic-sized pool could be surrounded by up to 50 gallons of urine, a new study has revealed. Scientists tested for an artificial sweetener called acesulfame potassium, which is consistently present in urine, making it easy to monitor pool levels. In the tests, they found that 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 filled with around 17 gallons. Although Olympic swimmers have admitted to urinating in pools regularly (along with the 19% of adults who say they've done it at least once), it is generally not an accepted practice. Despite urine itself being sterile, compounds can react with disinfectants such as chlorine -- causing them to become volatile and lead to eye and respiratory irritation.