Sweetener can track pee in the pool

Researchers estimate that swimming pools contain 30 to 80 mL of urine for each person who’s jumped in. The problem—aside from the ick factor—is that urine reacts with chemical disinfectants in the water to form potentially harmful by-products. To track the safety of pools and hot tubs, scientists would like to find a chemical marker of how much pee is actually in the water. Xing-Fang Li and coworkers at the University of Alberta propose that the artificial sweetener acesulfame K—used in products such as beverages and baked goods, often in combination with other sweeteners—could be that marker. Humans don’t metabolize it, so it’s excreted intact in urine. Li and coworkers used liquid chromatography and tandem mass spectrometry to measure acesulfame K in 250 samples from 31 pools and hot tubs in two Canadian cities. They also measured the corresponding input tap water (Environ. Sci. Technol. Lett. 2017, DOI: 10.1021/acs.estlett.7b00043). The team found the sweetener in all pool and tub samples at concentrations that ranged from 30 ng/L to 7,110 ng/L, compared with 15 ng/L or less in tap water samples. Using the average amount of acesulfame K in a human urine sample, the researchers then estimated that urine can make up 30 of the liters in a standard 420,000-L, 25-m-long community pool. The ubiquity of acesulfame K suggests that it could indeed be used as a urinary marker for tracking water quality in pools and hot tubs, the researchers note.