By CHERYL HOGUE
The germ-killing ingredient in an array of drug store items is already a target of advocates because of fears that it could breed a resistant superbug or harm development of frogs.
But now, this chemical, triclosan, is showing up in dolphins. This finding could generate closer regulatory scrutiny.
Triclosan is the active ingredient in many antibacterial soaps, deodorants, and toothpastes. This synthetic compound is also incorporated into plastic items such as baby-changing stations in public restrooms and in anti-odor cloth, such as shoe linings. And it's been detected in rivers, farm fields where sewage sludge is applied, and in people's bodies and breast milk.
For the past several years, triclosan has popped up in the news regularly. Many stories, pegged to cold and flu season, focus on the germ-killing abilities of plain soap versus antibacterial soap. Health experts say both types are efficient at getting germs off hands — and that there's no scientific benefit from using antimi- crobial soap as opposed to regular soap. Consumers keep buying antibacterial soap.
There is a concern that widespread use of antibacterial soaps will give rise to superbugs, just as injudicious use of prescription antibiotics can lead to the evolution of resistant germs. Some advocates are calling for a ban of the chemical in hand soaps used outside of hospitals and other medical settings.
But concerns about triclosan are bigger than just fears of resistant bacteria. The chemical is an endocrine disrupter. Scientists have found that triclosan can interfere with thyroid functioning. Exposure to the chemical can cause frogs to mature too quickly because of thyroid perturbations.
Since triclosan-containing hygiene products get washed off the body and down the drain, they end up at the local sewage treat- ment plant. The Soap and Detergent Association, an industry trade group, cites studies showing that processes in wastewater plants remove 90 to 98% of the chemical from the treated effluent that gets discharged into waterways. A lot of the chemical ends up adsorbed to bits of sludge.
Now, for the first time, scientists have found triclosan in marine mammals. Researchers from the National Oceanic & Atmospheric Administration, Environment Canada, and Florida Atlantic University discovered triclosan had bioaccumulated in dolphins off South Carolina and Florida. They reported their findings in the August-September 2009 issue of the journal Environmental Pollution.
Scientists say they aren't overly surprised by this new find- ing, since consumers buy and use so many triclosan-containing toiletries. These products are considered the main source of triclosan in water. According to the Environmental Protection Agency, plastic and cloth articles containing triclosan, often sold under the names of Biofresh and Microban, "are unlikely to contribute significant quantities of triclosan … to surface water."
Researchers haven't yet determined whether the small amount of triclosan found in dolphins could affect the animals' thyroid function — though there is some speculation it could.
The Soap and Detergent Association dismisses the detection of "minute traces" of triclosan found in dolphins. "The research basically tells us that the analytical science available today is amazing. You can find just about anything you want to just about anywhere if you're looking for it," says Paul DeLeo, the group's director of environmental safety.
As more data emerge on triclosan, the Food & Drug Administration and EPA will have to determine whether the chemical warrants further regulation.
EPA registers triclosan as a pesticide when it's used in objects like antimicrobial cutting boards or mildew-resistant mattress covers. In late 2008, the agency allowed pesticide uses of triclosan to continue, but the agency said it will revisit its decision in 2013 because of emerging science about the compound.
The environmental agency does not currently regulate triclosan as a water pollutant.
Meanwhile, FDA registers uses of triclosan for use in toiletries such as hand soaps, toothpaste, facial tissues, and antiseptics. It last updated its regulations on triclosan in 1994. Consumer and environmental groups are pressuring FDA to ban triclosan for uses outside of medical settings such as hospitals. Consumer advocates Food & Water Watch and Beyond Pesticides, an environmental group formerly known as the National Coalition Against the Misuse of Pesticides, primarily cite concern about antimicrobial resistance.
Keep your eyes open for more studies about this compound and whether it can affect mammals.
- Article in Environmental Pollution on triclosan in dolphins
- EPA 2008 decision on triclosan
- Soap and Detergent Association
- Beyond Pesticides backgrounder on triclosan
Cheryl Hogue covers national and international environmental policy for Chemical & Engineering News in Washington, D.C.
**From the quarterly newsletter SEJournal Fall 2009 issue.