University of Minnesota researchers have found dioxins derived from a common additive to hand soap, in Mississippi River sediments.
Triclosan is added to soaps and other consumer products as an antibacterial agent. It breaks down in water and sunlight into forms of dioxin that are building up in the environment, even as other forms of dioxin are declining. Dioxins, compounds that act as pollutants, are one cause of fish consumption advisories in Minnesota.
The researchers showed in earlier studies that the antibacterial agent, triclosan, breaks down in the environment to form specific types of dioxins. Now they've found both triclosan and its breakdown products in the mud of Lake Pepin.
People can avoid using soap with triclosan added, said William Arnold, a civil engineering professor.
"It takes a persistent shopper because I think 75 percent of liquid hand soaps contain triclosan, so you've got to go through the aisles and read the labels," Arnold said. "It's not a compound we need, and I think very often people don't realize the chemicals they're using ... may wind up somewhere else."
The Food and Drug Administration is launching a study of triclosan, which has been linked to disruptions of hormonal function and may also contribute to the formation of antibiotic-resistant bacteria.
The study was published in the Journal Environmental Science and Technology.