Researchers investigate soap chemical’s dirty secret

Triclosan is a bacteria-killing chemical found in 75 percent of hand soaps.

Alex Robinson

National Hand Washing Awareness Week started Monday, but University researchers have found there could be some nasty consequences for all the scrubbing.

Along with fellow researchers, civil engineering professor Bill Arnold is studying the effects of triclosan – a bacteria-killing chemical found in 75 percent of hand soaps – in several rivers and lakes throughout the state.

When chlorinated and exposed to sunlight, triclosan can become a dioxin: a toxic compound that can cause cancer.

Waste-water treatment plants don’t filter triclosan from water, but they do add chlorine to the water to kill bacteria. This practice can chlorinate triclosan, Arnold said, thus providing two of the three ingredients needed to produce a dioxin.

Certain types of dioxins accumulate in fish and sediment at the bottoms of lakes and rivers.

Arnold said the dioxin produced by triclosan is relatively low-powered, but it could still be harmful.

“We want to know the fate of this compound very well,” Arnold said. “If it is forming dioxins, that would be of real concern.”

As part of his research, Arnold will be taking samples of triclosan that have settled in the sediment of Wisconsin’s Lake Pepin and studying their reactions.

Jeff Buth, a graduate student helping Arnold with the project, is measuring the concentration of triclosan downstream from the water treatment plants in St. Paul.

He began the first test Monday.

There are hundreds of pharmaceutical chemicals like triclosan being put into rivers that many people aren’t aware of, Buth said.

“I think it’s just starting to grow in the public consciousness,” he said.

The Minnesota Pollution Control Agency and the U.S. Geological Survey found in 2000 there was triclosan in the state’s water.

Jennifer Groebner, MPCA spokeswoman, said although the agency found triclosan downstream from water treatment plants, it didn’t find any triclosan in the groundwater supply or in drinking water treatment plants.

The MPCA plans to do studies on triclosan in the future, but researchers don’t exactly know when, Groebner said.

“It is on our radar and we will be studying it at some point,” she said.

One of the problems with triclosan is that it is so popular in hand soaps, Arnold said.

“When we started doing this project I told my wife not to buy anything with triclosan in it,” Arnold said. “It turned out that she spent about 25 minutes wandering up and down the soap aisle trying to find a hand soap that didn’t have triclosan in it.”

Triclosan is the sixth-most common organic product found in waste water, according to MPCA statistics.

Deb Swackhamer, director of the Institute on the Environment, who is helping with the triclosan research, said pharmaceutical chemicals like triclosan could be indirectly harmful to people.

Because triclosan is found in low concentrations, bacteria living in the river could begin to fight off triclosan and eventually become immune to it, she said.

Swackhamer said because bacteria-killing chemicals are so popular, people’s immune systems are not prepared to fight off some diseases.

“Our society has moved more and more to make our environment cleaner,” Swackhamer said. “It could potentially cause disease outbreaks.”