Your Diet Soda is Freaking Out Fish

Researchers are scrutinizing the environmental effects of artificial sweeteners after detecting them in rivers and lakes.

January 2, 2014


Think about this the next time you reach for a diet soda: The artificial sweeteners diet drinks contain are so unnatural, they can survive your digestive tract, wastewater-treatment plants, sunlight, oxygen, and all of the microbes in nature, and live indefinitely in waterways.


Canadian researchers have just published a study in the journal PLoS One finding that sucralose (sold as Splenda) and acesulfame K (which isn't sold in packets but is common in diet drinks, usually in combination with another artificial sweetener) are very prevalent in rivers and lakes, and can make their ways into municipal water supplies.

The researchers, working for Environment Canada (equivalent to our Environmental Protection Agency), pulled samples from 23 different sites along the Grand River, a large river in Southern Ontario that receives treated wastewater from cities. They also took samples from household taps that get their water from municipal systems that draw from the Grand River watershed.

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At least one of the four sweeteners they tested for—cyclamate, saccharin, sucralose, and acesulfame—was present in every sample. Acesulfame was detected most frequently, at 21 of the 23 outdoor test sites, and was found more than 180 miles from the closest discharge point. But sucralose was found in the greatest concentrations. In fact, all four sweeteners were found at the highest reported concentrations in surface waters to date anywhere in the world.

It's not entirely clear what the presence of these sweeteners in waterways means from an environmental standpoint, says the study's lead author, John Spoelstra, PhD, a research scientist at Environment Canada and an adjunct assistant professor in the department of earth and environmental sciences at Ontario's University of Waterloo. In fact, he says, that isn't even their main concern. Artificial sweeteners, hearty as they are, are resistant to breaking down, he says, making them great tools in tracking the flow of wastewater, which is useful in researching other contaminants that might bypass wastewater-treatment plants.

"These compounds are designed not to break down in the body so they don't contribute calories" to foods and drinks (or your waistline), he says. Not only that, but they're popular, he adds. Sucralose is the most popular artificial sweetener sold in packets, and its presence in a growing number of processed foods (not to mention those little yellow packets) makes it a good tool for detecting contaminants in wastewater.

But if the sweetener's not breaking down in the environment, what's it doing to you? The Centers for Science in the Public Interest recommend avoiding both sucralose and acesulfame (which are sometimes used together) because both have been found to cause cancer in mice and rats. And the fact that they're unintentionally sweetening your next fish dinner doesn't help their sketchy reputations.

For more reasons to avoid artificial sweeteners, check out these 7 Hidden Dangers of Artificial Sweeteners.

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