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Antibacterial Products Pollute Freshwater Lakes

  • Jessica Berman

Lake Huron in the U.S. state of Michigan (file photo).

Lake Huron in the U.S. state of Michigan (file photo).

So-called “antibacterial” products are everywhere today - in stores, homes and classrooms around the world - to reduce the spread of colds and other infections. But a new study conducted in the United States has found that a chemical that gives soaps and hand creams their anti-germ properties is polluting freshwater lakes.

The anti-bacterial agent triclosan was approved for use in the U.S. in 1964 and was added to consumer products in the 1970s. Today, the disinfectant is in everything from soaps to laundry detergent, according to William Arnold, a civil engineering professor at the University of Minnesota in Minneapolis-St. Paul.

“We are using a chemical to wash our hands, brush our teeth and the like that isn’t actually necessary for the function of these products, that’s now accumulating in the environment and having potential effects out there," said Arnold.

Researchers pulled core samples from the bottom of eight Minnesota lakes, looking for evidence of triclosan in the sediment that had built up on the lakebeds.

“And so what we found is the concentration of triclosan was zero before 1964, and that it had increased over time, largely during the 1980s, when antibacterial hand soap came to the market," he said.

As the use of antibacterial soaps became widespread, more and more triclosan was washed down the drain with waste water, so the most recent sediments show the highest levels of the chemical.

Researchers say three chemical derivatives of triclosan are produced when the antibacterial agent is mixed with chlorine during the water purification process. And when triclosan and those derivatives are exposed to sunlight, they produce dioxin compounds. Arnold notes that dioxins harm the environment and get into the food chain, beginning with algae in lakes.

“People often think of algae on the lake - that’s bad - but algae are a very important component in the food chain," said Arnold. "And so if you disrupt that, that’s problematic. Triclosan is also known to make its way into fish via bioaccumulation, and so we expect these other compounds would do the same thing.”

Arnold says triclosan and its associated chemicals can build up in the ocean, as well as in freshwater lakes.

U.S. regulators have found no evidence that triclosan is any more effective than regular soap and water at killing germs, although as an ingredient in toothpaste it can reduce the risk of gum disease. The Canadian government, however, has started regulating the chemical.

An article by the University of Minnesota’s William Arnold and colleagues on the discovery of the antibacterial agent triclosan in U.S. lakes is published in the journal Environmental Science and Technology.