U research finds antibacterial ingredient in Minnesota lakes

The federal gov’t is re-evaluating the effects of a common soap ingredient.

U research finds antibacterial ingredient in Minnesota lakes

Rebecca Harrington

A common ingredient used in antibacterial soaps is building up in Minnesota’s lakes.

In a study  publicly published Tuesday, University of Minnesota researchers reported that increased use of triclosan — a common antibacterial ingredient — has resulted in the buildup of the chemical and its derivatives since its debut in 1964.

The U.S. Food and Drug Administration and the Environmental Protection Agency are currently re-evaluating the chemical’s potential danger to humans, animals and the environment.

The ingredient can also be used in detergents, cosmetics, toys and other household products, according to the FDA, but University researchers looked at where triclosan builds up after it washes down the drain.

William Arnold, co-author of the study and civil engineering professor, said he doesn’t use any products containing triclosan.

“People … should look at the bottles of products that they’re using at home,” he said, “and decide whether they should continue to use it based on the fact that the compound they’re washing their hands with is getting out into the nearby waters.”

The FDA previously concluded that triclosan was not toxic to humans but that it could be harmful to animals and the environment, according to the agency’s website. But new research like the University’s study has prompted another review.

Other studies have found triclosan to increase bacterial antibiotic resistance, to affect hormone regulation in animals and to be toxic to algae.

While triclosan is effective in toothpaste to prevent gingivitis, the FDA determined that using antibacterial soaps with triclosan is no different from washing with soap and water.

Because of the few benefits and possible risks, the Minnesota Department of Health advises people to stop using products with triclosan.

Daniel Engstrom, study co-author and director of the St. Croix Watershed Research Station, said the ingredient will lose industry popularity as more research emerges.

“We have a product that’s been used for a long time, and we’ve discovered that it has some potentially large detrimental effects,” he said. “It has relatively little positive effect. It’s an easy thing to eliminate without much loss to anyone.”

Beyond Pesticides and 80 other environmental groups are currently campaigning to ban triclosan from products in the U.S.

In the environment

The University study was the first to look for triclosan levels in lakes.

Cale Anger, co-author of the study, said the biggest problem is that the researchers found triclosan so far down in the lakebed because it had seeped through the water and soil to get there.

“It was in the ecosystem before it got to the sediment,” Anger said. “Organisms that are within the water column like fish could potentially be exposed to triclosan.”

To measure how much triclosan accumulated over time, the team used a long tube to extract a column of sediment from each lake. Researchers at the SCWRS then dated each column of sediment, and the team measured how much triclosan was present over the last 40 years.

When the chemical goes through water treatment plants, it can combine with chlorine to form chlorinated triclosan derivatives. When the wastewater enters lakes and sunlight hits these derivatives, they can form dioxins, which are a “group of chemically related compounds that are persistent environmental pollutants,” according to the World Health Organization.

Arnold said the dioxins formed from triclosan aren’t as toxic as many other dioxins, but their toxicity can increase as they continue to build up in the environment.

In the smaller lakes the team studied, Arnold said the triclosan dioxins made up more than half of all the dioxins present.

In Lake Superior, he said they even found triclosan and its derivatives nine miles away from where treated wastewater entered the lake.

The only lake they studied that didn’t contain traces of triclosan, Arnold said, was a small lake in the middle of the Lake Superior forest, because it didn’t have any wastewater input.

Next, Arnold and his lab plans to study chemicals structurally similar to triclosan to see if they have the same prevalence in the environment.

But whether the federal government will ban the chemical is hard to predict, he said.

“In terms of regulation,” he said, “that’s going to be up to the legislators to decide.”