Artificial Sweeteners Are Water Pollution Whistleblowers

When you drink sugar-free sodas or pour the lukewarm remnants of one down the drain, you probably don’t dwell on the journey those liquids then take to your local wastewater treatment plant. That journey, however, holds a lot of clues for researchers looking to track water pollution — all thanks to one substance that refuses to break down: sucralose.

Sucralose makes for an effective artificial sweetener because, despite tasting like sugar, your body doesn’t process it like other nutrients. In fact, it passes straight through your digestive system unscathed. As Florida International University professor Piero Gardinali explained it to Scientific American, “The whole purpose of having an artificial sweetener is that the body doesn’t recognize it as fuel, so you don’t use it for energy. We have seen that if you put it in a wastewater treatment plant, nothing happens to it because the microorganisms don’t recognize it as food, either.”

That’s why researchers like to call it a “tracer,” an abundant compound that doesn’t degrade very easily. For this reason, water quality specialists are able to tell whether wastewater has made its way into natural rivers and lakes by measuring levels of sucralose. It’s easier than, say, sampling the water for a host of possible contaminants. If they detect sucralose, they know whether to pursue a more thorough investigation into the source and extent of the pollution.

Water treatment specialists have so far used this method across the U.S. and in Europe. The U.S. National Oceanic and Atmospheric Administration plan to trace sucralose to study how Hurricane Irma affected water supplies. Luckily, early research shows sucralose poses little to no threat to wildlife exposed to trace amounts. Though there’s plenty left to learn about sucralose’s long-term impact on humans and natural habitats, for the time being, it’s a relatively safe tool for researchers.