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Study: Chemical in anti-bacterial soap turning up in freshwater lakes

When you use anti-bacterial soap, there’s a good chance there’s an ingredient called triclosan in it. It’s also added to things like body washes, some toothpastes, and dishwashing soap. You can find it listed as an ingredient on the label for many of those products.

But the Food and Drug Administration says there’s no evidence that using soap with triclosan in your home or office is any better at keeping you from getting sick than regular soap and water.  (Health experts say a good rule of thumb is to wash your hands with soap and water for 20 seconds: the length of time it takes to sing the "happy birthday" song twice.)

The FDA says triclosan is not known to be hazardous to humans. But the agency is re-evaluating the safety of triclosan in light of animal studies showing the chemical alters hormone regulation... and also because of studies suggesting that triclosan contributes to making bacteria resistant to antibiotics.

Credit FDA
Antibacterial soaps and body washes, and toothpastes are considered over-the-counter drugs by the FDA. So, if they contain triclosan, it'll be listed on the label.

A new study in the journal Environmental Science and Technology finds triclosan is showing up in freshwater lakes, including Lake Superior.

Bill Arnold is a professor of civil engineering at the University of Minnesota and an author of the study. He and his team took core samples from the sediment of eight lakes of different sizes in Minnesota.

"We found that in all the lakes there’s triclosan in the sediment, and in general, the concentration increased from when triclosan was invented in 1964 to present day. And we also found there are seven other compounds that are derivatives or degradation products of triclosan that are also in the sediment and also increasing in concentration with time."

All of these lakes have inputs from wastewater treatment systems.

"Triclosan goes through the wastewater treatment system, and the wastewater treatment plant actually does a pretty darn good job of removing it. 90 to 95 percent of it is taken out, but we use so much triclosan that the rest of it gets through, and three of the compounds we found are chlorinated triclosan derivatives, and they’re formed in the last step of wastewater treatment, when the wastewater is disinfected before it’s discharged and the disinfectant is chlorine. So that creates these three new compounds. And then triclosan and these three new compounds, when they’re exposed to sunlight, each of them undergoes a reaction that forms a dioxin, so that’s where the other four compounds come from."

Arnold says in some cases, the levels of triclosan they measured in the sediment were approaching levels that could be of concern.

"Because it’s known to be toxic to algae. So, we didn’t look at the levels in the water, but in the sediment, but in some cases they’re rather high in the sediment. For the other compounds we’re not sure, because the toxicity of them really hasn’t been studied."

The American Cleaning Institute, the trade group for the cleaning products industry, continues to maintain the safety of triclosan.  (The group released this statement yesterday).  But at the same time, both the FDA and the Environmental Protection Agency are re-evaluating the effects of triclosan on human health and the environment.

Bill Arnold says toxicologists and human health experts continue to study the potential effects of triclosan.

"I think this is a case where consumers can certainly put pressure on the market. So if consumers look at their products and don’t buy things with triclosan, they’re making their voice heard. Or they can also talk to the retailers and the manufacturers and tell them they don’t want this product if that’s the choice they make, if they don’t like the fact that it’s going beyond their sink and into the environment."

Arnold notes that while U.S. federal agencies continue to evaluate triclosan, Canadian officials declared it an environmental toxin last year, and are taking steps to regulate the chemical.

Rebecca Williams is senior editor in the newsroom, where she edits stories and helps guide news coverage.